Trial Outcomes & Findings for Neuroplasticity in TBI and Schizophrenia (NCT NCT03995368)

Neuroplasticity in TBI and Schizophrenia

Electroencephalography (EEG) measures the brain's activity while viewing simple visual stimuli or listening to simple auditory tones. MMN is measured while listening to a series of auditory tones, and is derived as the difference in responses to common stimuli minus rare stimuli (e.g., stimuli presented 90% of the time minus stimuli presented 10% of the time). A more negative value indicates stronger MMN, a more positive value indicates a stronger Repetition Positivity (RP) to the Standard stimuli, and a more negative value indicates a stronger Deviant Negativity (DN) to the Deviant stimuli. The investigators examined the deviant negativity, repetition positivity, and the MMN (which is defined as the difference between the standard-deviant), at three different standard tone repetition sequences (2, 6, or 36). In each case, the RP, DN, and MMN get stronger (i.e., larger amplitude) as the number of standard repetitions (2, 6, 36) increase.

This LTP task compares visual evoked potentials (VEPs) derived from the EEG before and after a period of extended visual stimulation (tetanization). We measured VEP amplitudes to two different checkerboard patterns before (pre-) and at three time points after (post-) a 10-minute prolonged tetanization checkerboard. VEPs were measured to tetanized (i.e., the same stimuli used in the 10-minute tetanization) or not tetanized (a different checkerboard pattern than the one used in tetanization) stimuli, prior to baseline (pre-), and at 5- (Post 1), 10- (Post 2), and 15- (Post 3) minutes after tetanization. This resulted in 4 VEP measurements for each tetanized and non-tetanized checkerboard. We focused on relative changes from baseline for evidence of plasticity and input specificity (i.e., tetanized vs. non-tetanized stimuli) at each of the 3 post-tetanization time points.

The MATRICS Consensus Cognitive Battery (MCCB) measures cognition in seven different domains (speed of processing, attention/vigilance, working memory, verbal learning, visual learning, reasoning and problem solving, and social cognition) and provides a SINGLE summary t-score (age and gender corrected) of overall cognitive functioning. The range of T-scores for a normal control population is between 0 to 100 with a mean of 50 and standard deviation of 10. Higher scores indicate better overall cognitive functioning.

Participants watch 9, short video clips of a person recounting a personal story. The participant must continuously rate how the person in the video is feeling while telling the story. The participant's ratings are then correlated with the ratings of the person who was in the video rating how they felt recounting their story. The average correlation for the 9 videos is the dependent variable, with higher positive correlations indicating higher empathic accuracy.

Community integration will be assessed by administering the Community Integration Questionnaire, which has 3 sub-scores (home, social, and activities). A higher score indicates better community integration.

Participants view a series of 56 faces depicting one of seven different emotions (happy, sad, surprised, angry, afraid, disgusted, and neutral). The total number correctly identified faces is the outcome measure, with higher scores indicating better performance. Scores range from 0-56, with 56 indicating 100% accurate facial affect identification.