use of alpha-theta biofeedback. in research designed to identify the subjective states associated with eeg rhythms, she trained subjects to increase the abundance of alpha, beta, and theta activity using visual feedback and recorded their subjective experiences when the amplitude of these frequency bands increased. she also helped popularize biofeedback by publishing a series of books, including new mind, new body (1974) and stress and the art of biofeedback (1977). mulholland and peper (1971) showed that occipital alpha increases with eyes open and not focused, and is disrupted by visual focusing; a rediscovery of alpha blocking. green and green (1986) investigated voluntary control of internal states by individuals like swami rama and american indian medicine man rolling thunder both in india and at the menninger foundation. they brought portable biofeedback equipment to india and monitored practitioners as they demonstrated self-regulation. a film containing footage from their investigations was released as biofeedback: the yoga of the west (1974). they developed alpha-theta training at the menninger foundation from the 1960s to the 1990s. they hypothesized that theta states allow access to unconscious memories and increase the impact of prepared images or suggestions. their alpha-theta research fostered peniston's development of an alpha-theta addiction protocol. sterman (1972) showed that cats and human subjects could be operantly trained to increase the amplitude of the sensorimotor rhythm (smr) recorded from the sensorimotor cortex. he demonstrated that smr production protects cats against drug-induced generalized seizures (tonic-clonic seizures involving loss of consciousness) and reduces the frequency of seizures in humans diagnosed with epilepsy. he found that his smr protocol, which uses visual and auditory eeg biofeedback, normalizes their eegs (smr increases while theta and beta decrease toward normal values) even during sleep. sterman also co-developed the sterman-kaiser (skil) qeeg database. birbaumer and colleagues (1981) have studied feedback of slow cortical potentials since the late 1970s. they have demonstrated that subjects can learn to control these dc potentials and have studied the efficacy of slow cortical potential biofeedback in treating adhd, epilepsy, migraine, and schizophrenia. lubar (1989) studied smr biofeedback to treat attention disorders and epilepsy in collaboration with sterman. he demonstrated that smr training can improve attention and academic performance in children diagnosed with attention deficit disorder with hyperactivity (adhd). he documented the importance of theta-to-beta ratios in adhd and developed theta suppression-beta enhancement protocols to decrease these ratios and improve student performance. the neuropsychiatric eeg-based assessment aid (neba) system a device used to measure the theta-to-beta ratio was approved as a tool to assist in diagnosis of adhd on july 15, 2013. however, the field has recently moved away from the measure. this move has been caused by the general change in the population norms in the past 20 years (most likely due to the change in the average amount of sleep in young people). electrodermal system feré demonstrated the exosomatic method of recording of skin electrical activity by passing a small current through the skin in 1888. tarchanoff used the endosomatic method by recording the difference in skin electrical potential from points on the skin surface in 1889; no external current was applied. jung employed the galvanometer, which used the exosomatic method, in 1907 to study unconscious emotions in word-association experiments. marjorie and hershel toomim (1975) published a landmark article about the use of gsr biofeedback in psychotherapy. meyer and reich discussed similar material in a british publication. musculoskeletal system jacobson (1930) developed hardware to measure emg voltages over time, showed that cognitive activity (like imagery) affects emg levels, introduced the deep relaxation method progressive relaxation, and wrote progressive relaxation (1929) and you must relax (1934). he prescribed daily progressive relaxation practice to treat diverse psychophysiological disorders like hypertension. several researchers showed that human subjects could learn precise control of individual motor units (motor neurons and the muscle fibers they control). lindsley (1935) found that relaxed subjects could suppress motor unit firing without biofeedback training. harrison and mortensen (1962) trained subjects using visual and auditory emg biofeedback to control individual motor units in the tibialis anterior muscle of the leg. basmajian (1963) instructed subjects using unfiltered auditory emg biofeedback to control separate motor units in the abductor pollicis muscle of the thumb in his single motor unit training (smut) studies. his best subjects coordinated several motor units to produce drum rolls. basmajian demonstrated practical applications for neuromuscular rehabilitation, pain management, and headache treatment. marinacci (1960) applied emg biofeedback to neuromuscular disorders (where proprioception is disrupted) including bell palsy (one-sided facial paralysis), polio, and stroke. "while marinacci used emg to treat neuromuscular disorders, his colleagues used the emg only for diagnosis. they were unable to recognize its potential as a teaching tool even when the evidence stared them in the face! many electromyographers who performed nerve conduction studies used visual and auditory feedback to reduce interference when a patient recruited too many motor units. even though they used emg biofeedback to guide the patient to relax so that clean diagnostic emg tests could be recorded, they were unable to envision emg biofeedback treatment of motor disorders." whatmore and kohli (1968) introduced the concept of dysponesis (misplaced effort) to explain how functional disorders (where body activity is disturbed) develop. bracing your shoulders when you hear a loud sound illustrates dysponesis, since this action does not protect against injury. these clinicians applied emg biofeedback to diverse functional problems like headache and hypertension. they reported case follow-ups ranging from 6 to 21 years. this was long compared with typical 0–24 month follow-ups in the clinical literature. their data showed that skill in controlling misplaced efforts was positively related to clinical improvement. last, they wrote the pathophysiology and treatment of functional disorders (1974) that outlined their treatment of functional disorders. wolf (1983) integrated emg biofeedback into physical therapy to treat stroke patients and conducted landmark stroke outcome studies. peper (1997) applied semg to the workplace, studied the ergonomics of computer use, and promoted "healthy computing." taub (1999, 2006) demonstrated the clinical efficacy of constraint-induced movement therapy (cimt) for the treatment of spinal cord-injured and stroke patients. cardiovascular system shearn (1962) operantly trained human subjects to increase their heart rates by 5 beats-per-minute to avoid electric shock. in contrast to shearn's slight heart rate increases, swami rama used yoga to produce atrial flutter at an average 306 beats per minute before a menninger foundation audience. this briefly stopped his heart's pumping of blood and silenced his pulse. engel and chism (1967) operantly trained subjects to decrease, increase, and then decrease their heart rates (this was analogous to on-off-on eeg training). he then used this approach to teach patients to control their rate of premature ventricular contractions (pvcs), where the ventricles contract too soon. engel conceptualized this training protocol as illness onset training, since patients were taught to produce and then suppress a symptom. peper has similarly taught asthmatics who wheeze to better control their breathing. schwartz (1971, 1972) examined whether specific patterns of cardiovascular activity are easier to learn than others due to biological constraints. he examined the constraints on learning integrated (two autonomic responses change in the same direction) and differentiated (two autonomic responses change inversely) patterns of blood pressure and heart rate change. schultz and luthe (1969) developed autogenic training, which is a deep relaxation exercise derived from hypnosis. this procedure combines passive volition with imagery in a series of three treatment procedures (standard autogenic exercises, autogenic neutralization, and autogenic meditation). clinicians at the menninger foundation coupled an abbreviated list of standard exercises with thermal biofeedback to create autogenic biofeedback. luthe (1973) also published a series of six volumes titled autogenic therapy. fahrion and colleagues (1986) reported on an 18–26 session treatment program for hypertensive patients. the menninger program combined breathing modification, autogenic biofeedback for the hands and feet, and frontal emg training. the authors reported that 89% of their medication patients discontinued or reduced medication by one-half while significantly lowering blood pressure. while this study did not include a double-blind control, the outcome rate was impressive. freedman and colleagues (1991) demonstrated that hand-warming and hand-cooling are produced by different mechanisms. the primary hand-warming mechanism is beta-adrenergic (hormonal), while the main hand-cooling mechanism is alpha-adrenergic and involves sympathetic c-fibers. this contradicts the traditional view that finger blood flow is controlled exclusively by sympathetic c-fibers. the traditional model asserts that, when firing is slow, hands warm; when firing is rapid, hands cool. freedman and colleagues' studies support the view that hand-warming and hand-cooling represent entirely different skills. vaschillo and colleagues (1983) published the first studies of heart rate variability (hrv) biofeedback with cosmonauts and treated patients diagnosed with psychiatric and psychophysiological disorders. lehrer collaborated with smetankin and potapova in treating pediatric asthma patients and published influential articles on hrv asthma treatment in the medical journal chest. the most direct effect of hrv biofeedback is on the baroreflex, a homeostatic reflex that helps control blood pressure fluctuations. when blood pressure goes up, the baroreflex makes heart rate go down. the opposite happens when blood pressure goes down. because it takes about 5 seconds for blood pressure to change after changes in heart rate (think of different amounts of blood flowing through the same sized tube), the baroreflex produces a rhythm in heart rate with a period of about 10 seconds. another rhythm in heart rate is caused by respiration (respiratory sinus arrhythmia), such that heart rate rises during inhalation and falls during exhalation. during hrv biofeedback, these two reflexes stimulate each other, stimulating resonance properties of the cardiovascular system caused by the inherent rhythm in the baroreflex, and thus causing very big oscillations in heart rate and large-amplitude stimulation of the baroreflex. thus hrv biofeedback exercises the baroreflex, and strengthens it. this apparently has the effect of modulating autonomic reactivity to stimulation. because the baroreflex is controlled through brain stem mechanisms that communicate directly with the insula and amygdala, which control emotion, hrv biofeedback also appears to modulate emotional reactivity, and to help people with anxiety, stress, and depression emotions are intimately linked to heart health, which is linked to physical and mental health. in general, good mental and physical health are correlated with positive emotions and high heart rate variability (hrv) modulated by mostly high frequencies. high hrv has been correlated with increased executive functioning skills such as memory and reaction time. biofeedback that increased hrv and shifted power toward hf (high-frequencies) has been shown to lower blood pressure. on the other hand, lf (low-frequency) power in the heart is associated with sympathetic vagal activity, which is known to increase the risk of heart attack. lf-dominated hrv power spectra are also directly associated with higher mortality rates in healthy individuals, and among individuals with mood disorders. anger and frustration increase the lf range of hrv. other studies have shown anger to increase the risk of heart attack, so researchers at the heartmath institute have made the connection between emotions and physical health via hrv. because emotions have such an impact on cardiac function, which cascades to numerous other biological processes, emotional regulation techniques are able to effect practical, psychophysiological change. mccraty et al. discovered that feelings of gratitude increased hrv and moved its power spectrum toward the mf (mid-frequency) and hf (high-frequency) ranges, while decreasing lf (low-frequency) power. the heartmath institute's patented techniques involve engendering feelings of gratitude and happiness, focusing on the physical location of the heart, and breathing in 10-second cycles. other techniques have been shown to improve hrv, such as strenuous aerobic exercise, and meditation. pain in 2021, the national institute for health and care excellence recommended against the use of biofeedback in managing chronic pain in adults. chronic back pain newton-john, spense, and schotte (1994) compared the effectiveness of cognitive behavior therapy (cbt) and electromyographic biofeedback (emg-biofeedback) for 44 participants with chronic low back pain. newton-john et al. (1994) split the participants into two groups, then measured the intensity of pain, the participants' perceived disability, and depression before treatment, after treatment and again six months later. newton-john et al.(1994) found no significant differences between the group which received cbt and the group which received emg-biofeedback. this seems to indicate that biofeedback is as effective as cbt in chronic low back pain. comparing the results of the groups before treatment and after treatment, indicates that emg-biofeedback reduced pain, disability, and depression as much as by half.