Neurophysiologic Biomarkers for Cognitive Rehabilitation

Cognitive symptoms of schizophrenia interfere with daily life-from managing self-care, to more complex tasks like taking medications and living independently. Unfortunately, these cognitive symptoms are not corrected by 'standard of care' treatments (antipsychotic medications), although some schizophrenia patients may experience modest clinical and cognitive benefits from cognitive remediation. To enhance the clinical impact of cognitive remediation and other rehabilitative interventions for Veterans living with chronic psychosis, this study will develop novel brain-based tools to help identify those Veterans who are most likely to benefit from pro-cognitive therapies. These studies may advance predictive algorithms that improve functional outcomes and life quality in Veterans with schizophrenia.

This is an observational study recruiting Veterans with a diagnosis of Schizophrenia (SZ) and other Chronic Psychotic Disorders and Veterans in good general health (HS) who are enrolled in and/or receiving care at the VA San Diego Healthcare System. Eighty Veterans will undergo comprehensive neurophysiological, clinical, cognitive, and functional assessments in two "phases" (Phase 1: 30 SZ, 20 HS; Phase 2: 30 SZ).

In Phase 1 (Biomarker Optimization; Aims 1 & 2), Veterans will undergo systematic neurophysiologic testing designed to elicit spectral biomarkers linked to cortical excitation and inhibition ("E/I balance") during passive and stimulated conditions on two separate test visits (1-2 weeks apart). Experimental conditions will then be optimized for internal consistency and test-retest reliability using Generalizability Theory. The optimized biomarkers will be carried forward into Phase 2 (Biomarker Validation; Aim 3), where these neurophysiologic measures will be assessed before and after Veterans with SZ undergo 1 hour of cognitive training as a demonstration of neural system target engagement.

This proposal has 3 specific aims:

Aim 1. Identify the experimental conditions that optimize the psychometric properties (i.e., sensitivity to detect individual differences) of the spectral biomarkers linked to E/I balance.

Aim 2. Characterize the relationships of spectral biomarkers with rehabilitation-relevant outcomes.

Aim 3. Evaluate the sensitivity of the optimized E/I measures in predicting performance during an acute, 1-hour exposure to computerized cognitive training.