**3. Prospects for VR in motor rehabilitation**

Understanding the importance of ensuring the formation of proprioceptive sensations, when solving a range of physical rehabilitation tasks, is also based on a

**135**

stroke [17].

*Proprioception in Immersive Virtual Reality DOI: http://dx.doi.org/10.5772/intechopen.96316*

of various origins.

with VR [14].

further exercises [16].

more intense activation of neuroplasticity processes when performing motor tasks with multisensory and, first of all, proprioceptive reinforcement, demonstrated in a number of experiments both on biological models and in patients with different pathology. The formation of biofeedback stimulates the processes of neurogenesis and neuroplasticity, due to the formation of new interneuronal connections, initially of a functional nature, but subsequently fixed at the structural level due to the activation of latent connections between individual functional structures of the CNS. That is why VR is an ideal immersive environment that makes it possible to maximally activate the processes of neuroplasticity for more effective recovery of not only motor, but also cognitive impairments in patients with damage to the CNS

Learning how to perform new skills within the framework of solving motor tasks modeled in VR is of decisive importance for inducing neuroplasticity processes, and as a result, contributes to a more effective restoration of impaired functions due to various injuries of the CNS or the musculoskeletal system. The immersive environment created in VR is a particularly effective tool for carrying out tasks of interacting with objects in three-dimensional space. The restoration of this level of motor function is especially important in increasing the independence of patients with motor defects of varying severity, which is one of the ultimate goals of motor rehabilitation or habilitation. Additional technical capabilities in the form of using various sensors, telemetry during training in VR allow a detailed analysis of the motor activity of the rehabilitated person, which can serve as initial data for the formation of a recommendation system to increase the effectiveness of the rehabilitation process, or to adapt exercises during the rehabilitation process, for example, by gradually complicating them. Implementation, not allowing the

For example, today there is many studies that formed the basis of several publications demonstrating the effectiveness of restoration of upper limb functions in patients after acute cerebrovascular accident when using exercises

However, these studies were based only on clinical data carried out in patients in the late rehabilitation period after suffering acute cerebrovascular accident. At the same time, the high safety and effectiveness of such exercises in VR suggests that the use of virtual reality will also be effective in patients in the acute period, after acute cerebrovascular accident. Such results regarding the use of implicit multimodal VR with visual and proprioceptive confirmation of walking have been demonstrated in a study on the restoration of lower limb function in patients in the

One of the reasons underlying the effectiveness of using VR as a method for restoring motor function is the ability to model new motor tasks that make the rehabilitation process more interesting, increasing the motivation of patients for

VR can be used for multimodal sensory impact on the rehabilitated person. The addition of multimodal sensory reinforcements after performing the required interactions with virtual objects made it possible to use VR in a wide variety of areas, and it also significantly increases the potential for using this immersive environment in motor rehabilitation. Solving the problems of motor rehabilitation, using personalized, motor training, has a more significant impact on the processes of neuroplasticity than implicit or extra-contextual interaction with objects of the VR environment. For example, according to fMRI data, this method demonstrates a higher degree of activation of the motor cortex when performing specific motor tasks and when solving the problem of restoring motor disorders in patients after a

rehabilitated person to lose interest and motivation to practice.

acute period of stroke **Figures 1** and **2** [15].

#### *Proprioception in Immersive Virtual Reality DOI: http://dx.doi.org/10.5772/intechopen.96316*

*Proprioception*

conditions and tasks, thus achieving a personalized approach to solving rehabilitation problems [10]. In addition to restoring motor skills, VR can be considered as a tool in the treatment of cognitive impairments of various origins, in the treatment of post-traumatic stress disorder, as well as various pain syndromes. One of the promising options for the use of VR is its use in the study of the ontogeny of the nervous system, which will be extremely necessary for understanding the formation of a pathological process, since any pathology in the context of ontogeny can be considered as regressive development, i.e. return to earlier stages of the existence and functioning of the CNS as a whole or its individual components [11]. In this regard, it is extremely important to provide neuro-feedback, preferably multisensory, primarily through the visual and proprioceptive sensory channels, because the formation of motor skills without these sensory systems is not possible. In several studies on the adaptation of the motor system after the demonstrated visual inconsistency of movements in VR to movements in the real physical world, it was found that the activity of the visual-motor connection in children is higher than in adolescents and adults, since such adaptation to motor activity in real in the physical world, after such a demonstration in children, it was much slower [12, 13]. Over time, as they grow older, this connection weakens, but obviously, only because of functional restructuring, and not anatomical, therefore, in a saturated immersive environment, you can get the results of visual-motor interaction, which are not always achievable in the physical world. Thus, a separate study of the motor system, as well as its functioning in health and disease, without connection with sensory systems, is inappropriate and incorrect from a physiological point of view.

VR technology can be used to provide a meaningful and effective impact on various human sensory systems; it also provides significant opportunities for modeling their functioning to compensate for lost sensory and motor functions. Now, the most technically simple VR systems are with implicit interaction with VR objects. These VR environments allow the person to be rehabilitated to act as a passive observer of the displayed content, while interaction occurs through the visual and auditory channel. Some expansion of the application of this technology occurs due to the use of various manipulators or joysticks, while the interaction with VR objects acquires the features of explicit interaction, however, the manipulation of VR objects with the use of these VR devices by objects is surrogate in nature, not

The main problem in this interaction is the absence of physical sensations provided

by the proprioceptive system, namely, the feeling of weight, density of an object, position in space. The importance of these sensations in the process of rehabilitation or habilitation lies in the fact that most of the movements performed by a person are the result of the functioning of the proprioceptive system, which ensures all their diversity and successful performance, regardless of external and internal factors. Thus, locomotor activity, devoid of fine tuning, provided by biofeedback based on the proprioceptive system, becomes less effective, and in some situations it is simply impossible, for example, walking at night or interacting with an object in threedimensional space in the absence of visual control in patients with afferent paresis in the hand. An exception is interaction with objects in three-dimensional space, which is provided by cortical motor centers and the corresponding centers of praxis, in the implementation of which the visual analyzer has an equal or more significant role.

Understanding the importance of ensuring the formation of proprioceptive sensations, when solving a range of physical rehabilitation tasks, is also based on a

giving the fullness of physical sensations.

**3. Prospects for VR in motor rehabilitation**

**134**

more intense activation of neuroplasticity processes when performing motor tasks with multisensory and, first of all, proprioceptive reinforcement, demonstrated in a number of experiments both on biological models and in patients with different pathology. The formation of biofeedback stimulates the processes of neurogenesis and neuroplasticity, due to the formation of new interneuronal connections, initially of a functional nature, but subsequently fixed at the structural level due to the activation of latent connections between individual functional structures of the CNS. That is why VR is an ideal immersive environment that makes it possible to maximally activate the processes of neuroplasticity for more effective recovery of not only motor, but also cognitive impairments in patients with damage to the CNS of various origins.

Learning how to perform new skills within the framework of solving motor tasks modeled in VR is of decisive importance for inducing neuroplasticity processes, and as a result, contributes to a more effective restoration of impaired functions due to various injuries of the CNS or the musculoskeletal system. The immersive environment created in VR is a particularly effective tool for carrying out tasks of interacting with objects in three-dimensional space. The restoration of this level of motor function is especially important in increasing the independence of patients with motor defects of varying severity, which is one of the ultimate goals of motor rehabilitation or habilitation. Additional technical capabilities in the form of using various sensors, telemetry during training in VR allow a detailed analysis of the motor activity of the rehabilitated person, which can serve as initial data for the formation of a recommendation system to increase the effectiveness of the rehabilitation process, or to adapt exercises during the rehabilitation process, for example, by gradually complicating them. Implementation, not allowing the rehabilitated person to lose interest and motivation to practice.

For example, today there is many studies that formed the basis of several publications demonstrating the effectiveness of restoration of upper limb functions in patients after acute cerebrovascular accident when using exercises with VR [14].

However, these studies were based only on clinical data carried out in patients in the late rehabilitation period after suffering acute cerebrovascular accident. At the same time, the high safety and effectiveness of such exercises in VR suggests that the use of virtual reality will also be effective in patients in the acute period, after acute cerebrovascular accident. Such results regarding the use of implicit multimodal VR with visual and proprioceptive confirmation of walking have been demonstrated in a study on the restoration of lower limb function in patients in the acute period of stroke **Figures 1** and **2** [15].

One of the reasons underlying the effectiveness of using VR as a method for restoring motor function is the ability to model new motor tasks that make the rehabilitation process more interesting, increasing the motivation of patients for further exercises [16].

VR can be used for multimodal sensory impact on the rehabilitated person. The addition of multimodal sensory reinforcements after performing the required interactions with virtual objects made it possible to use VR in a wide variety of areas, and it also significantly increases the potential for using this immersive environment in motor rehabilitation. Solving the problems of motor rehabilitation, using personalized, motor training, has a more significant impact on the processes of neuroplasticity than implicit or extra-contextual interaction with objects of the VR environment. For example, according to fMRI data, this method demonstrates a higher degree of activation of the motor cortex when performing specific motor tasks and when solving the problem of restoring motor disorders in patients after a stroke [17].

**Figure 1.** *ReviVR rehabilitation walk simulator.*

**Figure 2.** *First-person view in ReviVR rehabilitation walk simulator.*

The data of objective methods for assessing changes in the activity of the cerebral cortex demonstrate the relationship between the specificity of the performed motor task and the degree of activation of neuroplastic changes.

Visual-motor and proprioceptive feedback, implemented in VR, provides realistic, up-to-date information during the rehabilitation exercise. It is realism and maximum proximity to physical sensations that are the most important factors that activate neuroplastic processes in the central nervous system (CNS).

Visual information, which is the most powerful sensory signal that is activated in the immersive environment, is a modeling factor for the reorganization of sensorimotor connections. For example, errors demonstrated during visual accompaniment of motor tasks performed in VR affect the motor and premotor cortex during motor learning, changing the activity of these zones [18–22].

**137**

*Proprioception in Immersive Virtual Reality DOI: http://dx.doi.org/10.5772/intechopen.96316*

activity of the visual cortex of the brain [35–39].

being rehabilitated [40].

rehabilitation exercises.

complexity [42–44].

brain [23].

Active and rewarding exercises (by demonstrating the progress of the performed exercise or another method) within the framework of the performed rehabilitation tasks can significantly enhance biofeedback, leading to a significant decrease in the number of errors in the restored movements, i.e. making them more energy efficient and accurate. According to fMRI data, at this moment there is a significant activation of the motor and premotor regions of the frontal cortex of the

The very observation and subsequent ideomotor presentation of this movement leads to a significant facilitation of the formation of motor evoked potential and increases intercortical interactions in the motor and premotor regions [24–27]. It should be noted that the implementation of all this activation of the motor areas through exposure, for example, on the visual analyzer, becomes possible due to the proven numerous intrahemispheric corticocortical connections [28, 29]. These connections combine the visual cortex with the motor, premotor, parietal, and frontal lobes into a single functional system [30–34]. At the same time, there is a large number of experimental studies that demonstrate that a significant number of neurons in the motor, premotor and parietal regions can be modulated by the

Moreover, in contrast to proprioception, the activation of which in the physical world is necessarily associated with active or passive movements of the limbs, visual neurofeedback in VR can be provided independently of the fact of movement, for example, by simply demonstrating it. Also, it is interesting that the demonstration of this movement can be significantly changed and, most importantly, it can be completed to its full volume, regardless of the initial motor activity of the person

Thus, visual biofeedback allows modulation of the motor system, without the need for active or passive movements. The visual system has a high degree of reliability and specificity in the implementation of this biofeedback, because visual afferentation predominates over other sensory modalities, such as proprioceptive or

An additional, but important rationale for the advisability of using the visual cortex as a sensory input for modulating motor function is that during an acute cerebrovascular accident, it is not damaged simultaneously with the motor or premotor cortex, due to their location in different blood supply basins of the brain, but namely carotid and vertebrobasilar. For acute cerebrovascular accident, in the first episode, the defeat of two pools is not a common manifestation of the disease. The defeat of the cortical representation of the visual analyzer in the form of hemianopsia and contralateral hemiplegia is observed only in the villous artery syndrome, but the preservation of the opposite visual fields allows using the VR environment for

Thus, VR allows the user to receive multimodal sensory information, which can cause a real sense of presence and provide cognitive, sensory and emotional immersion in the formed rehabilitation task, which has varying degrees of

The use of VR makes it possible to implement various modifications of the displayed object or its movement, highlighting it against the general background, for example, by changing the color, brightness or its shape. This opportunity allows the patient to focus on the target elements of the rehabilitation exercise, enhancing his motivation. With the help of VR, it is possible to achieve modeling of the conditions that in traditional therapy are carried out by limiting the movement of a hand that does not have motor impairments due to stroke, through its fixation to the trunk. To implement this type of therapy in VR, one can ignore the activity of a healthy limb (recorded by telemetry or contact sensors: electromyography, accelerometers,

auditory, and is used by a person more effectively in everyday activities [41].

#### *Proprioception in Immersive Virtual Reality DOI: http://dx.doi.org/10.5772/intechopen.96316*

*Proprioception*

**Figure 1.**

*ReviVR rehabilitation walk simulator.*

**136**

**Figure 2.**

The data of objective methods for assessing changes in the activity of the cerebral cortex demonstrate the relationship between the specificity of the performed

Visual information, which is the most powerful sensory signal that is activated in the immersive environment, is a modeling factor for the reorganization of sensorimotor connections. For example, errors demonstrated during visual accompaniment of motor tasks performed in VR affect the motor and premotor cortex during

Visual-motor and proprioceptive feedback, implemented in VR, provides realistic, up-to-date information during the rehabilitation exercise. It is realism and maximum proximity to physical sensations that are the most important factors that

motor task and the degree of activation of neuroplastic changes.

*First-person view in ReviVR rehabilitation walk simulator.*

activate neuroplastic processes in the central nervous system (CNS).

motor learning, changing the activity of these zones [18–22].

Active and rewarding exercises (by demonstrating the progress of the performed exercise or another method) within the framework of the performed rehabilitation tasks can significantly enhance biofeedback, leading to a significant decrease in the number of errors in the restored movements, i.e. making them more energy efficient and accurate. According to fMRI data, at this moment there is a significant activation of the motor and premotor regions of the frontal cortex of the brain [23].

The very observation and subsequent ideomotor presentation of this movement leads to a significant facilitation of the formation of motor evoked potential and increases intercortical interactions in the motor and premotor regions [24–27].

It should be noted that the implementation of all this activation of the motor areas through exposure, for example, on the visual analyzer, becomes possible due to the proven numerous intrahemispheric corticocortical connections [28, 29]. These connections combine the visual cortex with the motor, premotor, parietal, and frontal lobes into a single functional system [30–34]. At the same time, there is a large number of experimental studies that demonstrate that a significant number of neurons in the motor, premotor and parietal regions can be modulated by the activity of the visual cortex of the brain [35–39].

Moreover, in contrast to proprioception, the activation of which in the physical world is necessarily associated with active or passive movements of the limbs, visual neurofeedback in VR can be provided independently of the fact of movement, for example, by simply demonstrating it. Also, it is interesting that the demonstration of this movement can be significantly changed and, most importantly, it can be completed to its full volume, regardless of the initial motor activity of the person being rehabilitated [40].

Thus, visual biofeedback allows modulation of the motor system, without the need for active or passive movements. The visual system has a high degree of reliability and specificity in the implementation of this biofeedback, because visual afferentation predominates over other sensory modalities, such as proprioceptive or auditory, and is used by a person more effectively in everyday activities [41].

An additional, but important rationale for the advisability of using the visual cortex as a sensory input for modulating motor function is that during an acute cerebrovascular accident, it is not damaged simultaneously with the motor or premotor cortex, due to their location in different blood supply basins of the brain, but namely carotid and vertebrobasilar. For acute cerebrovascular accident, in the first episode, the defeat of two pools is not a common manifestation of the disease. The defeat of the cortical representation of the visual analyzer in the form of hemianopsia and contralateral hemiplegia is observed only in the villous artery syndrome, but the preservation of the opposite visual fields allows using the VR environment for rehabilitation exercises.

Thus, VR allows the user to receive multimodal sensory information, which can cause a real sense of presence and provide cognitive, sensory and emotional immersion in the formed rehabilitation task, which has varying degrees of complexity [42–44].

The use of VR makes it possible to implement various modifications of the displayed object or its movement, highlighting it against the general background, for example, by changing the color, brightness or its shape. This opportunity allows the patient to focus on the target elements of the rehabilitation exercise, enhancing his motivation. With the help of VR, it is possible to achieve modeling of the conditions that in traditional therapy are carried out by limiting the movement of a hand that does not have motor impairments due to stroke, through its fixation to the trunk. To implement this type of therapy in VR, one can ignore the activity of a healthy limb (recorded by telemetry or contact sensors: electromyography, accelerometers,

etc.) and not provide visual information regarding its movement [4, 14, 45–47]. Additional opportunities are provided by the use of the "brain-computer" interface based on the motor imagery paradigm and the P300, the use of which allows visualizing the movement of a limb with motor impairments when activity appears according to electroencephalography or functional near-infrared spectroscopy data recorded globally, with all scalp surface of the head, or only in specified areas, which are a projection onto the scalp surface of the head of the motor or premotor areas of the cerebral cortex. For example, the target signal can be used for classification within the brain-computer interface in the contralateral motor or premotor cortex, which may slow down the rate of onset of the "rehabilitation plateau" and increase the rehabilitation potential in patients with CNS pathology.

In the detected functional improvements obtained as a result of motor rehabilitation, sensorimotor activation was observed not only in the contralateral hemisphere, but also in the ipsilateral hemisphere, which indicated the activation of latent connections that were not active before the start of the rehabilitation measures [48–50]. The ongoing rehabilitation in VR and the progress obtained with it in the restoration of motor function are primarily associated not with the compensation of movements, which is the result of maladaptation, but with the restoration of motor function due to the activation of neuroplasticity processes in the motor and premotor cortex of the brain [51].


**Paper-Based Detection Device for Alzheimer's Disease—Detecting** β**-amyloid Peptides (1–42) in Human Plasma**

#### **Wei-Hsuan Sung 1,2, Jung-Tung Hung 3, Yu-Jen Lu 2,4,\* and Chao-Min Cheng 5,\***

Received: 12 April 2020; Accepted: 28 April 2020; Published: 30 April 2020

**Abstract:** The diagnosis of Alzheimer's disease (AD) is frequently missed or delayed in clinical practice. To remedy this situation, we developed a screening, paper-based (P-ELISA) platform to detect β-amyloid peptide 1–42 (Aβ42) and provide rapid results using a small volume, easily accessible plasma sample instead of cerebrospinal fluid. The protocol outlined herein only requires 3 μL of sample per well and a short operating time (i.e., only 90 min). The detection limit of Aβ42 is 63.04 pg/mL in a buffer system. This P-ELISA-based approach can be used for early, preclinical stage AD screening, including screening for amnestic mild cognitive impairment (MCI) due to AD. It may also be used for treatment and stage monitoring purposes. The implementation of this approach may provide tremendous impact for an afflicted population and may well prompt additional and expanded efforts in both academic and commercial communities.

**Keywords:** Alzheimer's disease; β-amyloid peptide; paper-based ELISA; P-ELISA, point of care testing

Alzheimer's disease (AD) is one the most common irreversible neurodegenerative diseases across the globe. The massive number of people affected worldwide totals nearly 44 million [1]. AD results in drastically impaired cognitive function and a reduced capacity to perform even daily routines and activities. Currently, AD diagnosis relies heavily on symptomology with symptom-dependent tools including guidance from the following: (a) National Institute of Neurological and Communicative Disorders and Stroke AD and Related Disorders Association (NINCDS-ADRDA, UK) and (b) Diagnostic and Statistical Manual of the American Psychiatric Association (DSM-IV/DSM-5) [2]. As a result, AD diagnosis is frequently missed or delayed in clinical practice [3]. More recent criteria such as those provided by the National Institute on Aging and the Alzheimer's Association (NIA-AA) include the use of biomarkers (e.g., β-amyloid and tau) for diagnostic support [4]. As a result, focus has rightly begun to shift toward developing early-stage methods for the detection of possibly potent AD biomarkers.

Most existing diagnostic methods, e.g., neuroimaging, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR), are not suitable for point-of-care (POC) testing in their current state because they rely on highly sophisticated machinery and equipment, complicated operating procedures, and invasive or destructive sampling methods. Several newer studies have demonstrated greater creativity and have overcome problems by developing new POC testing devices to detect AD-related biomarkers. For example, an electrochemical immuno-sensing approach has been demonstrated for the detection of β-amyloid peptide 1–42 (Aβ42) at pM levels in a relatively shorter period of time than can be accomplished with an ELISA [5]. Stravalaci et al. described a novel immunoassay based on surface plasmon resonance (SPR) that specifically recognizes biologically active oligomers of the β-amyloid peptide (Aβ) [6]. Despite these advances, there is still an urgent need for rapid, e ffective, and easily used POC devices for early AD screening. The above-mentioned biosensors are not currently practical enough for clinical validation because they may be costly, involve a relatively time-consuming processes (e.g., immunoassay based on SPR requires a 5 h incubation period to produce a maximal signal), or they may require sophisticated signal readers. On the other hand, our paper-based POC device for the detection of Aβ42 is rapid, e ffective, inexpensive, and requires no sophisticated laboratory equipment. This process relies on an easily accessible body fluid, plasma, that facilitates minimally invasive first-step screening within one and a half hours.

A paper-based ELISA (P-ELISA) has previously been used to successfully detect proteins such as vascular endothelial growth factor (VEGF), as well as noncollagenous 16A (NC16A) autoimmune antibody toward diagnosis of various diseases such as age-related macular degeneration, bullous pemphigoid and *Escherichia coli* O157:H7 infection [7–10]. We have now demonstrated a P-ELISA system to detect Aβ42 in plasma. The aim of our study was twofold: (1) to expand the field of biomarker-dependent AD screening, as the use of biomarkers to support diagnosis has gained value and momentum, and, (2) to develop a specific POC tool using a P-ELISA to detect Aβ42 in both bu ffer and plasma systems. Based on its appropriate limit of detection (LOD), shorter operation duration, and lower cost, this method might set an example for the development of other approaches employing AD-related biomarkers for early stage screening, pre-treatment monitoring, in-treatment monitoring, and post-treatment follow-up. To our knowledge, our study is the first to apply a P-ELISA to detect plasma Aβ42.

Several studies have supported the important role of Aβ42 in the development of AD and have indicated that Aβ42 level dysregulation is responsible for the abnormal accumulation of Aβ42 plaques in the hippocampus and cortex [11,12]. For this reason, Aβ42 has been identified as a diagnostic biomarker, and anti-Aβ-directed therapies have been developed to combat AD [13]. With reliable detection at the core of any diagnostic approach, we first developed a bu ffer system-based P-ELISA tool to detect Aβ42 in 10-fold dilutions from 1 ng/mL to 1 pg/mL. An outline of our process is provided in Scheme 1 (below). After completing our P-ELISA process (as shown in the supporting movie), we visually interpreted the colorimetric output signal and used a smartphone camera (Apple, 1 Infinite Loop Cupertino, CA 95014, USA) to record the results. This process eliminates the need for any other specialized detector device. Colorimetric assays are particularly well-suited for use in resource-poor settings where plate readers and fluorescence scanners are rare but smartphones are relatively common. We converted our P-ELISA colorimetric results to eight-bit grayscale with ImageJ software using the formula: gray = (red + green + blue)/3. The color intensity was measured from min to max and defined as [experiment zone intensity] − [blank zone intensity]. The Mann–Whitney U test was used to compare the median mean intensity of di fferent Aβ42 concentrations. The LOD was calculated as 63.04 pg/mL, as determined by nonlinear regression fits. Figure 1 displays the significant di fference (*p* < 0.001) found between the group with concentrations at 1 ng/mL and our negative control group. The grayscale color intensity values at Aβ42 concentrations of 100, 10, and 1 pg/mL were significantly di fferent (*p* < 0.01) compared to the grayscale color intensity value of the control group.

**Scheme 1.** Schematic of our paper-based ELISA (P-ELISA) device development and test procedure for the detection of β-amyloid peptide 1-42 (Aβ42) concentrations in both buffer and plasma systems.

**Figure 1.** Colorimetric results (intensity) from our paper-based ELISA (P-ELISA) test for β-amyloid peptide 1-42 (Aβ42) concentrations in a buffer system. The color intensity difference between our 1 pg/mL Aβ42 concentration and our control was very significant. (\*\* *p* < 0.01; \*\*\* *p* < 0.001).

Clinically, biomarkers have been used to screen for AD, but these approaches have required semi-invasive cerebrospinal fluid (CSF) sampling via lumbar puncture and/or the use of costly neuroimaging techniques [14]. Transitioning the use of these biomarkers to portable and reliable POC diagnostic devices has been challenging. Cerebrospinal fluid Aβ42 assays may be a more accurate reflection of the central amyloid pathology associated with AD, but there has been some reluctance to employ this approach for routine analysis because of the risk associated with external drains and severe disturbances in CSF [15]. For this reason and others, there have been increased interest and research into the use of more easily accessible sample sources, such as plasma, that contain measurable quantities of Aβ42 suitable for clinical assessment [16]. Previous studies have reported that intra-cerebroventricular injection of Aβ42 is correlated with plasma Aβ42 levels in a mouse model, thus confirming the in vivo mixing of CSF and plasma Aβ42 pools [17]. In humans, a weak positive correlation was also observed between plasma and CSF Aβ42 levels [18]. Moreover, increasing evidence had indicated that plasma Aβ42 concentration may be a risk predictor for AD [19], though some studies have produced controversial results [20]. Kim et al. outlined a filtration-based approach for distinguishing between normal plasma Aβ42 levels and those of patients with AD [21]. Mayeux et al. found mean plasma Aβ42 levels of 82.4 6 ± 8.6 pg/mL among patients with AD and subsequently found baseline mean plasma Aβ42 levels of 68.7 pg/mL and follow-up levels of 76.5 pg/mL in individuals with AD in a later study [22,23]. Using variable capture antibodies and analytical platforms, a wide range of mean plasma Aβ42 levels, from 36 to 140 pg/mL, have been reported in patients suffering from AD [24]. We elected to examine plasma Aβ42 concentration using our own unique P-ELISA approach, employing the same process and equipment employed in our buffer system analysis. We used four sets of plasma samples containing four different concentrations of Aβ42; 0 (control), 10 pg/mL, 100 pg/mL, and 1 ng/mL. For our secondary antibody, we used horseradish peroxidase (HRP) conjugated anti-rabbit antibody (Cat. No.: 7074, Cell Signaling Technology, 3 Trask Lane, Danvers, MA01923, USA) on plasma samples 1 and 2, and we used HRP-conjugated anti-rabbit antibody (Cat. No.: Ab6702, Abcam, Discovery Drive Cambridge Biomedical Campus, Cambridge CB2 0AX, UK) on plasma samples 3 and 4. A comparison between the two secondary antibodies is shown in Table 1. In Figure 2, plasma samples 1 and 2 displayed significant differences (*p* < 0.05) compared to the control for spiked Aβ42 concentrations of 100 pg/mL and 1 ng/mL, respectively. Plasma samples 3 and 4, however, displayed significant differences (*p* < 0.05) compared to the control for spiked Aβ42 concentrations of 10 and 100 pg/mL. From these results, we gathered that secondary antibody selection does appear to affect the performance of our P-ELISA platform. Our plasma system results were also approximately 10 times less sensitive than those from our buffer system. This may be explained by the fact that Aβ42 has to be measured in the matrix as a derivative of blood, which contains very high levels of plasma proteins such as albumin, clotting factor, and immunoglobulin G (IgG), all of which interfere with the application and interpretation of biochemical marker assay results [25,26]. There is room for improvement in the sensitivity and reliability for a plasma-based P-ELISA. Despite these difficulties, a plasma-based P-ELISA system may be used for early AD screening, as suggested by Blennow et al. [27]. Furthermore, repeated longitudinal measurements of plasma Aβ42 level may be useful for routine follow-up to determine disease progression and monitor therapy.

**Figure 2.** Colorimetric results (intensity) from a paper-based ELISA (P-ELISA) test for β-amyloid peptide 1–42 (Aβ42) concentration in a plasma system. The secondary antibody used in plasma 1 and 2 was from Cell Signaling Technology, while that used in plasma 3 and 4 was from Abcam. The limit of detection (LOD) for tests using plasma 1 and 2 was approximately 100 pg/mL, while the LOD for tests using plasma 3 and 4 was about 10 pg/mL. (\* *p* < 0.05).

Clinical AD is thought to be preceded by a long asymptomatic or mildly symptomatic period that may be initiated 15–20 years Fprior to the onset of clinical signs [28]. This pre-dementia period is primarily composed of two parts: (1) preclinical AD and (2) amnestic mild cognitive impairment (MCI) due to AD development (Figure 3). Preclinical AD consists of the following three stages: (1) stage 1, which is manifested by the evidence of amyloidosis; (2) stage 2, which is characterized by not only amyloidosis but also evidence of neurodegeneration; an, (3) stage 3, a combination of amyloidosis, neurodegeneration, and subtle cognitive decline not meeting the criteria for MCI [29]. Compared to preclinical AD, amnestic MCI due to AD is defined as noticeable cognitive impairment resulting from underlying AD pathology. Because the development of AD is irreversible and progressive, there is an increasing need for biomarker-based screening tools to identify patients in preclinical or early clinical stages of AD. These patients would be greatly benefited by early intervention before more severe and irreversible damage occurs to the brain. In the past decade, a number of studies have made great efforts to develop biomarker-based screening tools and POC testing platforms to diagnose AD. Nakamura et al. validated the clinical utility of a blood-based Aβ assay using immunoprecipitation and mass spectrometry to predict brain Aβ burden [30]. Garyfallou et al. demonstrated an electrochemical immunosensor that can be easily integrated into portable devices to diagnose AD using plasma immunoglobulins [31]. Tonello et al. developed a POC testing system based on screen-printed electrochemical sensors (SPES) [32]. This study, however, is the first to demonstrate a P-ELISA system for Aβ42 detection in human plasma. It is challenging to measure Aβ42 due to antibody masking, Ab oligomerization, and Ab complex formation [33]. Plasma Aβ42 is also hard to use for diagnosing late-onset AD as a single time-point measure due to the considerable overlap with changes in the normal, aging population and the onset of vascular diseases [18,34]. We hope to promote the use of a P-ELISA for early screening, routine follow-up analyses, as well as AD monitoring in living patients as an adjunct to care. If detected at concentrations associated with risk, Aβ42 levels can be modified, as demonstrated by Boada et al., who describe a process for modifying Aβ42 concentration in plasma using plasma exchange (PE) and albumin replacement that improved cognition in patients with mild-to-moderate AD [35]. Our P-ELISA platform can help optimize therapeutics and improve disease

progression prediction [36]. P-ELISA methods provide several advantages compared to conventional ELISA methods (Table 2). First, the entire P-ELISA process, from antigen immobilization to colorimetric reaction, can be completed within one and half hours; by contrast, a conventional ELISA requires at least six-to-eight hours to complete. Second, a P-ELISA requires only 3 μL of sample per test zone, while conventional ELISA requires more than twenty-five times that. Finally, P-ELISA results can be quantified with simple devices, such as smartphone cameras, which increases their usability and broadens their impact. Further research could result in the production of a paper-based multiplexed assay incorporating peptide-detecting ELISA to create a multi-step, all-in-one diagnostic device [37,38]. We have accomplished the first step toward this goal, creating a paper-based device for peptide detection, with this study.

**Figure 3.** The role of point-of-care (POC) β-amyloid peptide 1–42 (Aβ42) testing for patients with preclinical Alzheimer's disease (AD), amnestic mild cognitive impairment (MCI) due to AD, and AD dementia.

**Table 2.** Comparison between the paper-based ELISA (P-ELISA) and conventional enzyme-linked immunosorbent assay (ELISA) systems for the detection of β-amyloid peptide 1–42 (Aβ42) using plasma and cerebrospinal fluid (CSF) samples.

This study outlines our development of the first P-ELISA tool for Aβ42 detection with demonstrated potential for testing human plasma. Our findings underscore the potential for employing a P-ELISA for both pre-clinical AD screening and post-diagnosis treatment monitoring. Compared to commonly-used Aβ42 detection methods, the P-ELISA offers five principal advantages: (1) rapidity, (2) small sample and reagent volume requirements, (3) cost-effectiveness, (4) readily available equipment and materials, and (5) improved clinical safety due to the fact that required samples involve the appropriation of plasma as opposed to CSF via lumbar puncture. P-ELISA techniques require some improvement in accuracy, precision, and long-term stability to render them more commercially viable. However, we found our approach to be highly sensitive, as evidenced by the 63.04 pg/mL LOD value attained in our buffer system experiments. In conclusion, our P-ELISA system is a promising candidate for the early screening of AD pre-dementia period and the post-diagnostic monitoring of AD, especially in small laboratories and in developing countries where cost and convenience are more critical.

**Author Contributions:** Conceptualization, Y.-J.L. and C.-M.C.; methodology, C.-M.C.; validation, J.-T.H.; formal analysis, W.-H.S.; investigation, W.-H.S.; resources, C.-M.C.; data curation, Y.-J.L.; writing—original draft preparation, W.-H.S.; writing—review and editing, W.-H.S.; visualization, W.-H.S.; supervision, Y.-J.L. and C.-M.C.; project administration, Y.-J.L. and C.-M.C.; funding acquisition, Y.-J.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** The study was supported by the project 'CMRPG3F0883- of Linkou Chang Gung Memorial Hospital, Taiwan and the project 'MOST 107-2628-E-007-001-MY3- as well as the project 'MOST-107-2314-B-182-020- of Ministry of Science and Technology, Taiwan.

**Conflicts of Interest:** The authors declare no conflict of interest.


**1. Introduction**

The neurohormone melatonin (MEL) (N-acetyl-5-methoxytyramine) is produced in the pineal gland and can be also found as metabolite in plants. Moreover, the synthesis of MEL derives from the aminoacid tryptophan, leading to 5-hydroxytryptophan, serotonin, and finally, N-acetylserotonin. Moreover, MEL can also be produced by *O*-serotonin methylation followed by N-methoxytryptamine acetylation by the action of yeast [1, 2].

MEL content has been reported in seeds, for example, rice or corn and roots, leaves, or fruits of a significant range of plants. The occurrence of MEL has also been reported in olive oil, especially in extra virgin olive oil, and in sunflower oil [3]. Moreover, the content of MEL has also been reported in grapes and wines [4]. Scientific literature has revealed that MEL is formed after fermentation with wine yeast, mainly due to *Saccharomyces cerevisiae* [5].

MEL is a key modulator of human health, showing antioxidant, anticarcinogenic, or neuroprotective capacity between others [6]. The biological capacity of their main metabolites as N-1-acetyl-N-2-formyl-5-methoxyquinuramine (AFMK) and N-1 acetyl-5-methoxyquinuramine (AMK) is also significant. AFMK is considered a potent antioxidant compound, and AMK is also a potent antioxidant being able to inhibit the biosynthesis of prostaglandins related to diazepam receptors [7]. As other secondary metabolites, MEL can promote antioxidant enzymes and/or neutralize free radicals [1]. In vivo studies have also reported the antioxidant capacity of MEL, which decreases chronic oxidative stress related to aging [8] and reduces blood pressure in men with chronic hypertension [9]. MEL has been successfully used for sleep disorders restoring circadian rhythm and is especially effective in population with neurodegenerative illnesses.

The amphipathic property of MEL allows it to cross some physiological barriers, being present in the cytosol, mitochondria, and different biological membranes [10]. Therefore, MEL provides biological properties where it is needed.


**2. Literature review**

### **2.1 The significance of case-based learning as a teaching methodology**

Case-based learning is highly recognised because of the positive impact it has on learning and teaching, and it promotes interactive learning [1]. It is a method that focuses on solving problems in the classroom and in real-life situations [1, 2]. Literature highlights that case study is the method that allows interdisciplinary learning and deals with solving societal issues [9, 10]. The method encourages creativity and prepares a well-rounded student who can also make decisions in the future. Furthermore, it enhances presentation skills when giving feedback to the audience; hence, students need to work very hard to provide constructive feedback. Teachers also need to quickly give positive feedback about the tasks to motivate students to work harder.

### **2.2 Case-based learning promotes deep learning**

Case-based learning promotes deep learning unlike surface learning since students can take control of their learning and gain new knowledge in the process. Deep learning is described as the understanding of content knowledge by students [11, 12]. Brookhart [13] explains that when students acquire knowledge, they need to apply it in and outside the school. Consequently, Shulman [14] proposes that teachers need to be well-equipped in content knowledge and to deliver it using the relevant pedagogies. Literature indicates that when using a case study, higher-order thinking

### *Enhance Learning among Natural Science Learners in a South African Rural District Using… DOI: http://dx.doi.org/10.5772/intechopen.113352*

develops, and students are able to operate at higher levels of Bloom's taxonomy of cognitive learning [10, 15]. Moreover, the same authors state that Bloom's taxonomy [16] came with a framework that emphasises the following aspects: recalling knowledge, analysing and evaluating, rather than just teaching students to remember facts (rote learning). To us, it means the scenarios given in class need to promote higher levels on Bloom's taxonomy of cognitive learning.

Bloom [16] states that learning is divided into three domains: (a) cognitive: mental skills (knowledge), (b) affective: growth in feelings or emotional areas (attitude or self) and (c) psychomotor: manual or physical skills (skills). The three domains are very important, and teachers need to apply them in the lesson. One of the three domains, the affective domain, encourages teachers to use relevant instructional methodologies that would allow educational activities, for instance, paying attention when the teacher starts the lesson as well as during the lesson. In the affective domain, five characteristics are very important [5], and they relate to each other for a lesson to be successful. Receiving, responding, valuing, organisation and classification by value or value complex are among these traits. The domain urged teachers to implement effective instructional techniques that would enable learning activities, addressing the following: Paying attention both when the teacher begins the lesson and when it is being taught.

If students receive the newly learned knowledge positively [6], then the learning and teaching becomes effective. When learners receive the lesson enthusiastically, they will respond constructively by participating in the lesson actively either working as individuals or working as groups. Hence, it is important for teachers to constructively align the learning outcomes with the assessment criteria, moreover, to use the relevant method that will encourage the students to be actively engaged. Participating in the lesson means the value of the lesson is treasured by learners, and they demonstrate their appreciation by asking questions, discussing, and seeking clarity when necessary.

### **2.3 Case-based learning enhances problem-solving skills**

Problem-solving is referred to as a problem-based learning strategy (PBLS; [17]). There is a connection between case-based learning and problem-based learning. When students are conducting case study tasks, they need to apply problem-solving skills of which they need to critically engage in research on the topic and give positive feedback. Five stages need to be performed when solving a problem, and these are investigating, developing, presenting work, analysing and evaluating the problemsolving process [17]. The stages will assist the teachers to guide the students before they can follow.

### **2.4 Challenges and benefits of case-based learning**

The literature recognises that case study is one of the top methods that can be used in the classroom as it prepares students in applying higher-order thinking [1]. Sunbul [2] and Cakmak [18] state that when the case study is used correctly, teamwork is promoted, communication becomes significantly enhanced and students are able to find real solutions to problems. Moreover, the author also highlights that the scenarios given to students can be examined by all students in class or as groups before teachers can do their evaluation. Bilen [19], Nas [20] and Gozutok [21] state that critical thinking becomes more advanced when students are involved in case discussions.

Preparing case studies takes a long time and can be difficult to conduct in overcrowded classrooms [2, 22, 23]. Therefore, teachers need to be mentored and guided in using the case-study method. Moreover, the above authors also mentioned that good preparation before the application is needed to avoid disappointments when conducting the session [2, 22, 23]. Thus, teachers need to get enough learner materials and training from the school management committee and the department officials. Current studies claim that support is the key to implementing curriculum effectively [24]. Furthermore, Phasha, et al. [25] highlights that the quality of education can be upgraded only if challenges encountered by teachers are positively addressed and all the stakeholders play an instrumental role in supporting the teachers.

### **2.5 Problem statement**

The study was triggered by challenges faced by teachers in the science field. Some of the teachers confirmed that science is not an easy subject, they struggle immensely when implementing the curriculum in class. They follow CAPS documents, which they struggle to analyse. In addition, they complained about being allocated a subject to teach without having a background in science or due to a shortage of teachers in that field. The study was conducted in one rural education district in South Africa's Eastern Cape Province. Findings revealed that educators in South Africa encounter challenges in terms of science resources, content knowledge and infrastructure [26]. The three aspects mentioned above are the focus areas that need to be prioritised before implementing the science curriculum. Thus, it is the researchers' responsibility to go deep and find out if teachers use the case-based learning method to enhance science learning.

### **2.6 Theoretical and conceptual background**

The study is underpinned by two theories, Vygotsky's [27] (1896–1934) social constructivism and Shulman's [14] pedagogical content knowledge. The two theories align with the study as they emphasise that the students need to be engaged and guided by a knowledgeable person to reach the academic level that is expected. The second theory posits that the knowledgeable person needs to master the content first before involving the student and using the relevant approach to drive the lesson. Since the two theories complement each other, the implication is that, before teachers make use of the case study approach, they should be familiar and knowledgeable with the content, understand the type of student and their environment before they can assign tasks. This implies that teachers must understand individual learners' needs so that they can prepare relevant tasks for them.

### **2.7 Research objective**

The paper sought to explore teachers' acknowledgement of the case study as a teaching method that promotes critical thinking in science learning.

### **2.8 Research question**

How do teachers use case-based learning as a teaching method that promotes natural science learning?

*Enhance Learning among Natural Science Learners in a South African Rural District Using… DOI: http://dx.doi.org/10.5772/intechopen.113352*

### **2.9 Research and methodology**

A mixed-method approach was employed in the study. The data were analysed using both qualitative and quantitative approaches. Descriptive statistics were used for quantitative data and themes were used to analyse qualitative data. To examine case-based learning used by teachers when teaching Natural Sciences (NS), this study employed a descriptive and survey design. A questionnaire was used to collect data. The study used purposeful sampling to select schools based on proximity to the researchers. Thirty out of sixty-seven schools are in six out of the eight circuits in the selected education district. The population was made up of 15 female and 15 male teachers.

### **2.10 Ethical considerations**

Ethical considerations such as informed consent, voluntary participation and withdrawal, confidentiality and for anonymity codes like Teacher 1 (T1), Teacher 2 (T2)…up to Teacher 9 (T9). The researchers also guaranteed that no participant would be put exposed or subjected to risk or harm as a result of their participation in the study.

### **3. Results**

Educators identified 44 responses on the strengths of the case study method. The responses are presented in descending order: simplifying otherwise complex activities/scenarios (13, 30%), promoting research skills/integrating and synthesising basic knowledge in real-life cases (10, 23%), exposing learners to real-life scenarios (9, 21%), fostering critical thinking and enhancing communication (7, 16%) and allowing discussions and cooperative learning (5, 11%).

The shortcomings of the case study method amassed 27 responses with the most commonly identified weakness being that the method was relatively more timeconsuming compared to other teaching strategies (15, 56%). The second common disadvantage identified was that case studies were difficult to utilise if learners were disinterested (8, 30%). The less common disadvantages were stated as promoting little in-depth learning and requiring specific skills on the part of the teacher (3, 11%) and learners (1, 4%) respectively.

### **3.1 Discussion**

### *3.1.1 Strengths*

Case study as a strategy that simplifies otherwise complex activities and scenarios was among the strengths identified by educators. Cakmak et al. [18] caution that the language used should not be too complicated to allow students to understand the scenario and be able to unpack it. Exposing learners to real-life scenarios is very important, Keller [1] explains that a case study is the best method to use in the classroom as it prepares students for post-secondary achievement. Sunbul [2] indicates that the case study method assists students to find operative solutions to problems that they encounter in similar real-life situations in a shorter time. Benefits identified by educators were promoting critical and analytical thinking,

improving communication, contributing positively to the development of critical thinking, problem-solving and decision-making skills. Previous studies [19–21] report that critical thinking is developed when students are engaged in case discussions. Moreover, for discussions and cooperative learning, students could learn through engaging in discussions, therefore, they enjoy the method [22]. Teamwork is significantly important and cooperative learning is the key for this method as students work in groups to find solutions.

Promotion of research skills, as well as integration and synthesis of basic knowledge in real-life cases, are other strengths mentioned by respondents. Respondents also mentioned that research skills are sharpened when using case-based learning. Hence, it is important for teachers to guide the student during the process.

### *3.1.2 Weaknesses*

Weaknesses mentioned by respondents included the consumption of relatively more time compared to other methods. Literature highlights that case studies consume large stretches of time and can be difficult to implement in congested classrooms [2, 22, 23]. Another weakness mentioned was that little in-depth learning was achieved and that specific skills on the part of the educator might be needed. Other studies have also demonstrated that case studies require educators to make good preparations before application [2, 22, 23]. Regarding the difficulty to implement the case study method if learners are disinterested due to the need for deep and critical thinking to solve the problem, several researchers have faced similar challenges. For example, Sunbul [2] reports that due to different challenges, it is often hard to implement the method.

Themes were drawn from the participants' responses on exploring case-based learning as a teaching method that enhances natural science learning. Themes were organised to connect with research questions to cater to NS teachers. The themes are as follows:

## *3.1.3 Qualitative findings*

Teachers agreed that there are methods that promote higher-order thinking concerning the case study. Their verbatim quotes are as follows:

*The case study involves investigations, and they promote higher-order thinking. An example, when giving learners a question, it needs a conclusion at the end. So the learner will critically think about what happened up to the last stage. It is not easy, sometimes since it requires specific skills on the part of the teacher, I still need support (T1) (T2).*

*Case study promotes higher thinking, e.g., When I give them questions like "What are stem cells? How do you get them? How are they harvested?" Then learners will do*  *Enhance Learning among Natural Science Learners in a South African Rural District Using… DOI: http://dx.doi.org/10.5772/intechopen.113352*

*a lot of thinking (T3). Problem-solving and investigation are part of the case study, they encourage higher order thinking and learners can voice out whatever they know and also ask questions (T9).*

*Working as groups assists the students to brainstorm and come up with facts. Activities need to be aligned with the content specified in the CAPS policy document and allow students to think outside the box, however, consume relatively more time as compared to other methods and students delay with the feedback (T4). The following approaches that will increase thinking skills are investigations, problem-solving (T7).*

*A case study is not easy for me, I need support. I am used in the lecture and textbook method. Lack of support is a challenge. When I attend the workshop, it does not work for me because they are too theoretical than practical, we need the practical part of NS (T6) (T8).*

### **4. Discussion**

To promote higher-order thinking, the participants revealed that investigations enhanced higher-order thinking. Previous studies such as Keller [1], Grassberger, Wilder [3] and Nkhoma [4] indicate that case study encourages students to learn more and apply critical thinking. Moreover, Winn et al. [6] encourages the use of cognitive learning strategies so that students can apply deep learning and actively participate in the lesson. The present researcher concurs with the authors above, teachers with the teaching and lecturing background profess the practicality of the method. It gives students the freedom to look for different learning materials that will assist them in compiling or demonstrating the task given.

Some of the science teachers confirmed that case study requires specific skills. Literature revealed that, to master the required skills concerning the case study, one needs to have good problem-solving skills and be able to understand the investigation skills [17]. Subsequently, Akbulut and Hill [5] notes that authentic learning activities motivates student teachers to be prepared for the 21st century classrooms. The participants mentioned that group work promotes learning and teaching when implementing a curriculum using a case study. Cakmak [18] and Sunbul [2] state that case study promotes teamwork, good communication skills among the group and students find constructive solutions to problems. Teamwork is immensely important; students divide the tasks and allocate duties to everyone in the group. However, group work can disadvantage shy students by further alienating them while those who are significantly confident seize the opportunity to dominate in the group.

Some of the participants complained that case study consumes relatively more time, and literature avers that case-based learning takes a long time and can be difficult to conduct [2, 22, 23]. The present researchers are of the view that exposing students to real-life scenarios or projects that demand critical thinking is particularly crucial. Therefore, it is important to prepare students to be able to apply their minds, evaluate the problem and emerge with good decisions.

There is an existing need for support, as revealed by some of the science teachers. Getting support in the core business of the school is very significant, so the school managers need to monitor and implement positive interventions that will support

teachers. Literature notes that support is the key to the successful implementation of the curriculum [24]. While Phasha et al. [25] mentions that challenges encountered by teachers need to be addressed immediately to avoid unnecessary delays in the curriculum implementation.

### **4.1 Summary of findings**

The findings revealed that case-based learning exposes learners to real-life scenarios and promotes critical and analytical thinking; however, the challenges are compounded in congested classrooms and lessons take a long time when implemented in overcrowded classrooms. Case-based learning prepares students to apply problem-solving, investigation and decision-making skills. However, there are some metacognition challenges experienced such as time-constraints and need for thorough preparation before conducting science sessions as lack of preparation negatively affects learners with learning barriers.


Contents

### **Preface XI**

#### Chapter 8 **Techno-Economic Analysis of a Peltier Heating Unit System Integrated into Ventilated Façade 123** Lizbeth Salgado-Conrado, César Martín-Gómez, María Ibáñez Puy and José Antonio Sacristán Fernández

Preface

discharging concrete bed storage system.

In this book, various aspects of heating, ventilation, and air-conditioning (HVAC) systems are investigated. HVAC systems are milestones of building mechanical systems that provide thermal comfort for occupants accompanied with indoor air quality. HVAC systems can be classified into central and local systems according to multiple zones, location, and distribu‐ tion. Primary HVAC equipment includes heating equipment, ventilation equipment, and cooling or air-conditioning equipment. Central HVAC systems are located away from build‐ ings in a central equipment room and deliver the conditioned air by a delivery ductwork system. Central HVAC systems contain all-air, air-water, or all-water systems. These two systems are presented in Chapter 1. In Chapter 2, two methods for sizing the network for the transport of the air, from the air handling unit to the terminal units, are explained. Chap‐ ter 3 deals with a methodology of energy management intended to analyze, evaluate, and suggest actions to save and encourage the efficient use of electric energy of HVAC systems during stages of planning, design, construction, or audit existing systems applied to regions with hot and dry climates such as desert or semidesert locations. Chapter 4 focuses on HVAC systems for modern animal housing systems. The advanced simulation tools for transient energy simulation of existing buildings are studied in Chapter 5. The relevance of the topic due to the decision of problems of the economy of resources in heating systems of buildings is presented in Chapter 6. Chapter 7 discusses the use of the vehicular combined thermal development system with phase-transitional thermal accumulators. A techno-eco‐ nomic analysis of a thermoelectric heating unit (THU) prototype is reported on in Chapter 8. This chapter shows a technical description, which includes design, improvements, operating conditions, and mathematical model of THU system. In Chapter 9, authors analyze theoreti‐ cally the temperature distribution and energy storage ability of a simultaneous charging and

**Mohsen Sheikholeslami Kandelousi (M. Sheikholeslami)**

Department of Mechanical Engineering Babol Noshirvani University of Technology

Babol, Islamic Republic of Iran


*Article* **Teaching HCI Skills in Higher Education through Game Design: A Study of Students' Perceptions**

#### **Pedro C. Santana-Mancilla 1,\*, Miguel A. Rodriguez-Ortiz 1, Miguel A. Garcia-Ruiz 2, Laura S. Gaytan-Lugo 3, Silvia B. Fajardo-Flores 1 and Juan Contreras-Castillo 1**

Received: 22 March 2019; Accepted: 10 May 2019; Published: 14 May 2019

**Abstract:** Human-computer interaction (HCI) is an area with a wide range of concepts and knowledge. Therefore, a need to innovate in the teaching-learning processes to achieve an effective education arises. This article describes a proposal for teaching HCI through the development of projects that allow students to acquire higher education competencies through the design and evaluation of computer games. Finally, an empirical validation (questionnaires and case study) with 40 undergraduate students (studying their fifth semester of software engineering) was applied at the end of the semester. The results indicated that this teaching method provides the students with the HCI skills (psychology of everyday things, involving users, task-centered system design, models of human behavior, creativity and metaphors, and graphical screen design) and, more importantly, they have a positive perception on the efficacy of the use of videogame design in a higher education course.

**Keywords:** learning by doing; serious games; game design; human computer-interaction; HCI education

#### **1. Introduction**

Human-computer interaction (HCI) courses often use the curriculum of the Association for Computing Machinery Special Interest Group on Computer-Human Interaction (ACM SIGCHI) as a foundation [1]. As reported by Greenberg [2], this curriculum should not be used directly when it comes to an individual course within a career, rather as a complete curriculum to train HCI specialists.

In the software engineering program in the School of Telematics at the University of Colima, HCI is an individual course taught in a project-based approach to engage students in research of real problems [3], thus providing students with the basic knowledge of HCI and the different areas that converge in this field is ideal. Computer games (also called video games) are a rich opportunity to bring this approach into a traditional HCI course.

In this paper we present two main contributions: first, we present a proposal for using the design and evaluation of computer games as a learning tool to teach HCI to undergraduate students, and, second, we provide an empirical validation of this proposal to explore students' attitudes to understand if the students believe that using video games allow them to learn higher education skills. The objective of this research was to explore HCI students' perceptions regarding the use of game design to acquire the needed skills in the subject, and the research question that we aimed to answer was: does the use of videogame design improve the students' perception of their learning?

#### **2. Teaching Human-Computer Interaction**

A report published by Hewett et al. [1], in addition to giving a formal definition of human-computer interaction, proposed a syllabus and contents for HCI courses in which students could understand the multidisciplinary nature of the field, leaving an open range of topics that interact in the academic training in HCI.

Many years have passed since the publication of that report and the research in the area has grown a lot. However, until recent years, the conclusions were the same. As Churchill et al. [4] states, there is still no agreement on the range of topics that integrate the area and on how to teach HCI courses, how much fundamental theory must be presented, and how much practice students should perform; there are divided opinions about it, and they are investigating the philosophies and best practices to update the ACM 1992 curriculum proposal and support the present and future of HCI education [1].

Despite the lack of agreement on the percentages of theory versus practice, there is a point where most converge since that first report [1]: the development of human-computer interfaces is a matter of engineering and design, and, the subsequent learning of theoretical content, is enriched with the cooperative experience and can advance to a more mature level when students are required to solve the problems of real-life projects. Hartfield et al. [5] also mentioned that a combination of readings, classes, and written assignments is appropriate for teaching topics such as solutions to typical design problems and theories of human skills that are related to HCI; however, they also considered that these activities do not help HCI students to acquire practical skills in the design of technological solutions, and recommended hands-on exercises be carried out with real projects so students can learn by doing, as suggested by Pastel [6]. His work also mentioned that learning through real projects in collaborative groups is becoming the standard for the teaching of the HCI, and he made the observation that the students prefer this method of teaching since they can learn by doing and carrying out a meaningful project with their projects designs. Pastel [6] also made an essential contribution by adding research techniques to work, this was because, as he mentioned, there is a significant similarity between the scientific research process and the software development process. In addition to being research projects, students can use unique HCI devices or implementations.

Lorés et al., Koppelman et al., Reimer et al., Solano, and Urquiza-Fuentes et al. [7–11] also used a combination of theory and projects with real-life applications using user-centered design methodologies. In fact, Lorés et al. [7] combined the teaching of formal content with the development of a real-life project in a compulsory course within the HCI curricula at the University of Lleida (Spain). The work of Koppelman et al. [8] consisted of providing projects with a realistic context, inviting people from industry to serve as clients for the student projects and allowing teams to evaluate their designs with real users. Reimer et al. [9] used the studio-based approach to teach competencies in designing interactive objects in an HCI design studio course. Solano [10] presented an analysis of the teaching experience in an HCI course at the Universidad Autónoma de Occidente of Colombia and identified that problem-based learning is a good way to construct knowledge in real scenarios that can be improved. Urquiza-Fuentes et al. [11] presented a study to test the effect of using practical exercises in a human-computer interaction course, and they found that realistic projects are a viable approach to teach HCI and that students involved in this approach are significantly more motivated.

On the other hand, as mentioned by Serrano-Cámara et al. [12], it is essential to keep the students motivated, especially in generating intrinsic motivation [13] (which refers to doing something because it is inherently interesting or pleasant) because motivation is a central factor in learning and, as mentioned by the authors, improves results in knowledge and creativity. Urquiza-Fuentes et al. [11] suggested that collaborative learning encourages the use of high-level cognitive strategies, critical thinking, deep learning, deep understanding, and positive attitudes towards education and teamwork, according to the research that real-life project development combined with collaborative learning approaches keeps the students motivated; therefore, it turns out to be a positive strategy for teaching the HCI.

#### **3. Learning with Games**

The last report from the Entertainment Software Association [14], showed that the videogame industry has maintained a steady growth and a prominent place in the market, being one of the most successful application domains in the history of interactive systems [15].

Video games have not only been used for entertainment but also as an educational tool since the design of games for education provides valuable help in skills acquisition [16]. The design of video games with and educational purpose is known as serious games, a relatively new discipline that combines learning design with game mechanics and logic [17].

Williamson et al. [18] argued that video games are a compelling context for learning because it is possible to create and interact with virtual worlds to develop situated and contextualized understandings. Robertson and Howells [19] mentioned that there is research that argue to give players a mental exercise that generates a series of cognitive abilities, such as the planning of strategies for the resolution of problems, and also mentioned that not only the use of games contributes to learning, rather, they suggested the benefits of designing and building games as part of learning strategies since it involves students and education, and thus becomes an active experience.

In addition, Skrzyszewski et al. [20] remarked on the benefits of including the design and construction of video games as a learning strategy: this activity creates the opportunity to develop and increase creativity, technical skills, and the ability to work as a team. In addition, students can acquire an update on state-of-the-art technologies and techniques used in the process, and gain practical experience in different areas of computing. Although there exist arguments against learning with games, centered upon the lack of empirical evidence to support their effectiveness [17], we found that according to [21–23], there is pedagogical support for learning through the development of video games and that, in addition to the aforementioned, it increases motivation and makes the courses more attractive for students.

There are also examples of the application of video game design and development activities as part of HCI courses, such as the case of Dyck et al. [15] who mentioned that these environments do not put restrictions on how things should look or how the interaction should be, but reward innovation and performance that often leads to novel interaction, which have led to the production of many ideas for future work. Bernhaupt et al. [24] agreed that the design of video games, as part of an HCI course, allows for exploring new interaction techniques and experiences, allowing faster adoption of novel technologies, and, as an example, they mention the creation of Oculus Rift and the Kinect, of which Villaroman et al. [25] have proposed the latter as projects for HCI courses.

In addition, as mentioned by Covaci et al. [26], modern educational theories describe effective learning as active, experiential, situated, problem-based, and providing immediate feedback. The development of games can be the balance between play and learning activities, including this type of events in HCI courses, which is consistent with the theories of effective learning since, with the design and development of games and real-world situations, that allows students to develop skills for solving problems in a way that they also stay motivated [27,28].

#### **4. Experimental Study**

This study was implemented in a fifth semester mandatory human-computer interaction course, taught at the University of Colima in Mexico for the software engineering major. This course has been taught since 2009 and, during these years, the learning has been mixed, using projects with video games and learning with utility projects or administrative software.

The experiment was between subjects [29], in which students were taking the course when video games were used. This evaluation approach is a study design in which each group is only exposed to a single setup (i.e., learning with utility software or learning with video games). At the time of the study, the student population of the fifth semester in software engineering were 40:29 (72.5%) were male, 11 (27.5%) were female, and none of them had taken an HCI course before. In this

stage of their education, they already had skills in programming, data structures, and software development processes.

The study was designed to explore students' perceptions of the efficacy of video game design to acquire the required HCI competencies: knowing the importance of the correct design, application and evaluation of human computer interfaces, identifying paradigms, and state-of-the-art in the design of technological developments with the purpose of producing efficient, easy to use software interfaces to solve computing problems.

#### **5. The Games**

In this section we describe two examples of computer game projects that were designed and developed during the course. These games were selected because they were success cases since the students published their results in research conferences [30,31].

#### *5.1. Fallbox: Game Controlled by Head Tracking*

Fallbox is a 2D game (see Figure 1) played from the first-person perspective. It is based on head tracking using infrared led and the infrared camera of the Nintendo Wii Remote. The aim of this game is that players move their heads to control the game avatar (called Chilo) on the X axis. Chilo has to move to dodge the boxes that are falling down.

**Figure 1.** The computer game Fallbox. The avatar must dodge the falling boxes.

The game has 5 levels, with increasing difficulty in each level, because the boxes are falling faster. The player has a limited life (a 100% bar at start) that decreases each time Chilo is hit by a falling box.

#### *5.2. Shooter: Game with Multimodal Interaction*

This game is a 2D with a first-person perspective. The characteristics and goals of the game are simple: the user has to go through different scenarios in which he has to eliminate every enemy that appears within a time frame. The game integrated three different types of tangible multimodal interactions (see Figure 2):

**Figure 2.** The students create the interacting devices. The image illustrates a gesture interaction.

#### **6. HCI Teaching Process**

The course has been oriented to teaching through the design and evaluation of computer games and their interaction devices. This way students learn not only basic game design principles, but also acquire skills from the different areas that converge in the HCI area.

The course follows the proposal of Greenberg [2] that presented the teaching of HCI as a usability engineering process (see Figure 3), which has the purpose for students to acquire sufficient skills to make a reasonable design, develop, and evaluate of human-computer interfaces. Upon completion of the course, students must understand what a good design means, and have experience designing systems that are usable for people, which must be achieved by implementing interfaces through prototypes and practicing methods of evaluating the quality of the product.

**Figure 3.** Human-computer interaction (HCI) as a usability engineering process.

#### *6.1. Process of Design*

The design process in HCI is fundamental and designing includes learning and acquiring important knowledge by the students [2]: psychology of everyday things, involving users, task-centered system design, models of human behavior, creativity and metaphors, and graphical screen design.

The design of a game starts with a plan. It will help define the game story and its elements. The game plan contains the designs of characters and scenarios, in addition to the types and levels of interaction that the player will have with the game. To achieve this, the sketching technique proposed by Buxton [35] was used. This technique has proved to be an excellent means for people to start thinking about the process of product design in a simple way [36].

To evaluate the students' success during this stage of the course, students must generate the sketches with the initial design of the game and the interaction mechanisms (for examples, see Figures 4 and 5).

**Figure 4.** Design of the game mechanism.

**Figure 5.** Design of the interaction with the game control device.

#### *6.2. Process of Implementation*

The emphasis of the development process is on the behavioral domain: the tasks are concerned with the user interaction with the application and the view of the user. A variation of the user-centered methodology is used based on user-task analysis, where task-oriented methodologies ask that users attempt to complete a task in the system [37]. The first stage in the process is to identify a complete description of tasks, subtasks, and methods required to use a system, in addition to having a complete understanding of the user. With this process, designers have a clear understanding of the user requirements, and, therefore, could design better functionality according to the user. After gathering the users' task analysis, the constructional domain starts, which involves modelling, source code generation, and integration.

For the Fallbox game, in this stage the students identified the scenario of the game as a complete description of the user task:

"*Chilo is the youngest kid in the family. For this reason, his brothers throw boxes to stop him inside their house. The player must help Chilo avoid these boxes by moving his head and show his brothers that he can beat them.*"

Once the tasks were defined, the subtasks were defined: the avatar will interact only with falling boxes, the boxes will fall with increased speed, the scenarios will include non-playable objects (i.e., tables, chairs, beds, frets, stove, refrigerator), and the avatar will be controlled by the users' head movements.

At this point, the students have a clear understanding of the requirements, and they can start to build the game and the interaction devices. For the aforementioned game, they envisioned a device that should be placed on the player's head for head tracking that consisted of an infrared LED (see Figure 6) that points to a Wii Remote and is the responsible for indicating the position of the player to the avatar in the game. So, the player has to move her head to control the game and dodge the boxes that are falling down.

**Figure 6.** Head-tracking interaction device.

#### *6.3. Process of Evaluation*

To learn the competencies for the usability assessment, the students used a summative evaluation following the methodology proposed by Santana-Mancilla [38], called "IHCLab Usability Test for Serious Games".

The evaluation included the followings phases:

	- (1) Game heuristics questionnaire: an adapted and generalized game heuristics instrument based on previous applications reported by the literature [39,40].
	- (2) Game experience questionnaire (GEQ): The GEQ is divided in two dimensions: (1) four questions, where the learners had to give a score from 1 to 10, where 10 is the most significant, and (2) seven questions that measured some important indicators with a 5-point Likert scale.

#### **7. Case Study**

To validate the effectiveness of computer games use in the learning of HCI, as mentioned in Section 4, a between-subjects study was conducted with the two groups of students who followed the HCI course at the School of Telematics of the University of Colima in Mexico.

#### *7.1. Subjects*

Participants were 40 undergraduates studying their third year (fifth semester) with a software developer background (programming, algorithms, and data structures) and a basic hardware knowledge background (embedded systems and digital electronics). The school gave the informed consent for inclusion before the students were included in the study.

#### *7.2. Questionnaire*

A questionnaire (designed by our research group) to know the opinion of the students about their perception of the use of video games in HCI teaching was applied.

To validate the questionnaire contents, a group of experts in the area of HCI (expert judgment) used item analysis. The validity of content is essential when making inferences or generalizations from the results of the evaluation [41].

For this evaluation, four criteria were established:

To evaluate each criterion, the following response options were established:

A total of five teachers, working in different HCI areas, validated the questionnaire. From the evaluation, a set of changes were introduced in the structure of the questionnaire (language used, closing items, rearrangement of some questions), developing the version that was used in this study, which consists of six questions and is shown in Appendix A. It is important to mention that this questionnaire had already been applied in other studies by our research team [42], but is still in the process of further validation using the Cronbach's Alpha coefficient to validate the internal consistency of the instrument since it is calculated from the covariance between the elements analyzed. The results obtained in this study will contribute to the validation process of the questionnaire.

Each of the students in the intervention groups filled out the questionnaire and, since all students accomplished the instrument, the sample includes all the perceptions of the subjects under study and, thus, meets the requirement for saturation.

#### *7.3. Results*

95% of the students participating in the course thought that they learned the required HCI skills using the design and development of video games (see Figure 7). The remaining 5% considered that it was necessary to integrate additional content so that learning was more complete. The topics most commonly proposed for improvement were evaluation of video games, novel interaction devices, and graphic design.

This result showed a largely positive perception of the efficacy of use video games for skills development in higher education.

When asked how they thought their learning would have been if the teaching process were not with video game design, 100% said that the knowledge acquired would have been lower. Very related, the 85% percent mentioned that they would attend other courses that use video games as a learning tool.

**Figure 7.** Number of students' responses about acquiring the required HCI skills by gender.

Regarding if they enjoyed learning using computer games, 100% of the students enjoyed the course, and the following is some representative feedback:

Regarding the problems, difficulties or frustrations they could have during the project, they said the following:

Finally, the students made some suggestions to improve the experience.

#### **8. Conclusions**

Forty students who had participated in the HCI course were interviewed with an instrument following the conclusion of the semester. Participants were drawn from the human-computer interaction course of their undergraduate degree.

The use of computer games applied to HCI education has given us, in addition to learning, a motivating way of transmitting knowledge to students. The findings contribute to the learning-by-games literature by showing that students perceived value in learning by game design at the university level.

The approach of learning HCI through the design and evaluation of computer games has given results outside the course. To date we have nine undergraduate students who have created a computer game as a final project of their engineering studies based on the HCI course they attended. In addition, students and professors have published more than 15 research works (book chapters, journals, and conferences) in the field of video games and serious games with these projects and the lessons learned from the HCI course in the years that it has been offered.

By its nature, games offer constant challenges that students must be overcome to acquire the required skills, and these challenges allow the students to perceive that games can improve their required skills.

The evaluation has shown a broadly positive student attitude on how this game approach was perceived, demonstrating that, according to the perception of the students, games can have a positive effect on higher education.

The students' perceptions described here appear to require further investigation. These results have motivated a long-term randomized controlled trial where participants will be assigned to either an intervention or a control group to offer compelling evidence for the potential of designing video games to aid in the development of higher education competencies on HCI.

**Author Contributions:** Conceptualization, P.C.S.-M. and M.A.R.-O.; Formal analysis, P.C.S.-M., M.A.R.-O., M.A.G.-R., L.S.G.-L., S.B.F.-F., and J.C.-C.; Investigation, P.C.S.-M.; Writing—original draft, P.C.S.-M. and M.A.R.-O.; Writing—review & editing, M.A.G.-R., L.S.G.-L., S.B.F.-F. and J.C.-C.

**Funding:** This research received no external funding.

**Acknowledgments:** We thank all the students who participated in the case study during their HCI course.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Appendix A**

(1) Do you think you learned enough about HCI through the design and evaluation of a videogame? ( ) Yes ( ) No

(2) Do you think your knowledge of HCI would have been the same, smaller, or greater without having used the design and evaluation of videogames?

( ) Smaller ( ) The same ( ) Grater

(3) I would attend other courses that use video games as a learning tool.

( ) Agree ( ) Neutral ( ) Disagree

(4) In general, did you enjoy learning using video games? Explain

( ) Yes ( ) No

(5) Did you find any problem, difficulty, or frustration, in general, when using the design and evaluation of video games as a learning tool? If you had them, list the problems.

( ) Yes ( ) No

(6) If you could improve the experience of using video games in learning HCI, what would you change or add?

#### **References**

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