Study: NCT03655782

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: PATH neurotraining
Description: Improve visual timing and sensitivity in the dorsal stream. The mTBI subject will sit 57 cm in front of a computer monitor. During the presentation, the bars in the 'fish-shaped' window in the center of the screen formed by a sinusoidal grating, move left or right very briefly. When the screen goes blank, the subject reports which way the center pattern moved by pushing the left or right arrow key. A brief tone is presented after incorrect responses. The program adaptively changes the contrast of the test pattern so that the subject detects motion at lowest contrast possible. A sequence of patterns in each training cycle that are designed to optimally activate magnocellular neurons are shown to the subject. There are two programs, the first measures the contrast needed to see one direction of movement, and the second program measures the contrast needed to see two directions of movement, requiring memory.

Intervention type: BEHAVIORAL
Group type: SHAM_COMPARATOR
Intervention: Orientation Discrimination
Description: The sham intervention will be Orientation Discrimination training that is identical to PATH training except instead of low contrast sinewave gratings moving left or right, 100% contrast stationary test and background sinewave gratings are used, both red, green, and black and white gratings. These patterns are randomly oriented left or right, at decreasing tilt angles as the test grating's orientation is identified correctly. These patterns only activate parvocells in ventral pathways (Ungerleider \& Mishkin, 1982; Kaplan \& Shapley, 1986) instead of activating dorsal pathways, the key components of PATH neurotraining. Therefore, this task does not speed up the brain's visual timing, which is a function of the dorsal stream. For the Orientation Discrimination task, the subject pushes the left arrow key when the test pattern is tilted left and the right arrow key when pattern is tilted right. Otherwise the two training tasks use the same paradigm.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: N-Back Working Memory Training
Description: Participants are required to compare each item on a computer screen to the item that they saw n-items back in the sequence. The participant plays a simple game where they control the movement of an astronaut that needs to collect correct gems, avoid incorrect gems, and also obstacles, to succeed at the game. If the participants performs well then they can be advanced to the 2-back, 3-back, 4-back, etc where they make similar matches but to earlier items in the sequence. This gamified task consists of a color n-back with 6 colors (a new color every 3 seconds, requiring subjects respond to targets by tapping the screen and navigating the astronaut to the targets, and avoiding the distractors) with 30% targets, and where the n-level will change every 2 minutes depending on performance (increase if performance is \>85% and decrease if \<75%). Sessions consist of 10 \~2 minute blocks, each with n-level as determined by the adaptive procedure and with user paced breaks between blocks.