Patient 3 was a 19-year old female with a complicated history. Her TBI was not diagnosed at the time of her first hospitalization at age 14. According to her mother, she had vomited and had a severe occipital headache before falling asleep. She was unarousable in the morning and was taken to the hospital. A CT scan showed posterior fossa hematoma. She underwent occipital craniotomy with evacuation of a fourth intraventricular hemorrhage and inter-parenchymal hemorrhage. She developed hydrocephalus post-operation which required an external ventricular drain. She was unconscious for 3 days following the craniotomy. It took several days until she was able to remember the incident resulting in her TBI and communicated that she had received a hard blow with a soccer ball to the back of her head after school. At the time she felt dizzy. After she became medically stable, she began speech therapy. She also complained of diplopia and was given an eye patch. After all vascular investigations were negative; she was referred for comprehensive rehabilitation for mobility, activities of daily living, balance and vision. She also reported a second head trauma 4 years after the first accident. At this time, she suffered a blow to the head as a result of falling downstairs. She had headache, double vision and ataxia following this incident. Her medical report recorded a GCS score of 15 and no other systemic abnormalities. A CT scan and magnetic resonance imaging (MRI) revealed stable postoperative changes from occipital craniotomy associated with cerebral encephalomalacia and gliosis. At the time of participation in this study, she was attending University and living independently in dormitory accommodation.
Self-paced saccades were recorded using a SensoMotoric Instruments (SMI) monocular infrared video-based eye tracker (SensoMotoric Instruments, Berlin, Germany), that recorded left eye at 200 Hz with a spatial resolution of less than 1 . Stimuli were presented on a 20 inch LCD monitor (SAMSUNG, 2043BW, with a refresh rate 60 Hz and resolution of 1050x680 pixels) with patient sitting 67 cm from it with head stabilized using a chinrest. A 5-point calibration was conducted before recording eye movements and if the x-coordinate spatial accuracy was < 1 , eye movement recording (left eye) began. A fixation cross was presented in the center of the monitor. While recording, the fixation cross was substituted with two 1o black dots at 10o to the left and right side of the center for 30 seconds. Patient was asked to make volitional saccades between the two dots as fast and accurately as possible. The number of primary saccades was counted.
Eye movements throughout the abstract conjunctive search were recorded using an Eyelink II head-mounted eye tracker (SR Research). Viewing was binocular, but the left eye only was tracked as there was no disconjucacy of the eyes in any subject. Eye position was sampled at 500 Hz with spatial accuracy of 0.5 . The search task was presented using a short-throw projector (NEC, WT610) on a screen at a viewing distance of 130 cm, resolution of 1024 x 768 and subtended 62.8  x 38.2  of visual angle on the screen. Task presentation and eye tracking were controlled with SR Research Experiment Builder software. The task trials were created by R statistical software (A language and environment for statistical computing, R Foundation for Statistical Computing, Vienna, Austria, http://www.R-project.org). Each trial contained 59 red and green letter "d"s with green "b"s as distractors and one red letter "b" as the target, randomly positioned on a white background (Figure 1). Each letter subtended approximately 0.6  x 1  degrees of visual angle.
A 9-point calibration and validation were performed before starting the task and calibration was repeated if the spatial accuracy fell above 0.5 . Patient was required to locate a red letter "b" and press the button box as fast and accurately as possible. Each trial stayed on the screen until the subject reached his/her decision, indicated by pressing a button on a gamepad to end the trial or until an automatic time-out of 20 seconds. Ten trials were shown to the participant in every day of testing and training.
Eligible participants read the study information sheet and signed the consent form. They were reimbursed $10 per session for their participation as well as their public travel costs and parking fees. The study was approved by the University of Melbourne Human Research Ethics Committee (approval number: 1238522.1). Participants had normal or corrected-to-normal visual acuity as tested with a LogMAR chart at 3 meters and normal color vision as tested by the Ishihara test. Each participant was tested five times on five consecutive days on the self-paced and abstract search task to record baseline data. They subsequently began training, using the game Call of Duty, Modern Warfare II (Infinity Ward) for a total of 10 hours (1 hour per day for ten days), over a two-week period. Before each training session, participants were tested on the saccade and the abstract search tasks. Each session took 1 hour and 20 minutes to complete. Participants were also tested on the saccade and the abstract search tasks on two other occasions during the training period, once after 5 hours of training and once after finishing the training. Overall, the study included at least 17 sessions: 5 baseline testing sessions, 10 testing plus training sessions, 1 mid-training testing session, and 1 post-training testing session). These took at least 4 weeks for each participant to complete and did not include weekends.
On the first day of testing, tasks were explained to the patient and the experimenter ensured that the patient had learned the task by performing practice trials (five in each test) before recording. The testing procedure commenced with the self-paced saccade task. Following a variable rest period, the visual search task was presented to the patient.
Game training was performed using a 15.5-inch laptop (Dell, Latitude E6520) with 1920 x 1080 resolution. The monitor subtended 35.3  x 19.6  visual angle, when the participant sat 55 cm from the laptop. In the first training session, the content and aim of the game, different movements and weapons were explained to the trainee, who started playing the game by completing the first level or 'mission', which served as a tutorial. The participants subsequently played the game for 1 hour, taking breaks when required. The experimenter sat in the testing room and was available to assist and give feedback if needed. Participants played the single-player mode of the game, which comprised 17 missions. If a participant finished the single player mode, they played the advanced Special Ops section which consisted of five new levels with new objectives. After finishing the daily training, the participant's achieved level (mission) was recorded. If a mission was not completed, the participant started from that uncompleted mission the following day.
To investigate the influence of training on self-paced saccade rate and duration of fixation and visual search time in abstract search task, we used a procedure called percentage of non-overlapping data (PND) . PND is used in single-case analysis studies as one of the alternatives to visual trend analysis . For this technique, the percentage of data points during the treatment period which exceeds the best performance data within the baseline phase is used to index the effectiveness of an intervention. Here, effect size is based on the percentage of non-overlapping data between baseline and treatment phases of the single-case intervention trial: highly effective >= 90%, moderately effective 70-90%, minimally effective 50-70%, ineffective < 50% .