An examination of the moderating effects of neurophysiology on treatment outcomes from cognitive training in schizophrenia-spectrum disorders.

BACKGROUND: Impairments in neurocognition and community functioning are core features of schizophrenia and cognitive training techniques have been developed with the aim of improving these impairments. While cognitive training has produced reliable improvements in neurocognition and functioning, little is known about factors that moderate treatment response. Electroencephalographic (EEG) measures provide a neurophysiological indicator of cognitive functions that may moderate treatment outcomes from cognitive training. METHODS: Data from a clinical trial comparing two cognitive training approaches in schizophrenia-spectrum disorders were utilized in the current report. Cluster analysis was conducted to identify participant clusters based on baseline P300, mismatch negativity (MMN), and theta power during an n-back task, and the EEG measures were also examined as continuous predictors of treatment response. RESULTS: Three clusters were identified based on the baseline EEG variables; however, there were no significant differences in treatment response across the three clusters. Higher P300 amplitude and theta power during the n-back at baseline were significantly associated with greater improvements in a cognitive composite score post-treatment. None of the EEG measures were significantly associated with treatment outcomes in specific cognitive domains or community functioning. Change in EEG measures from baseline to post-treatment was not significantly associated with durability of cognitive or functional change at 12-week follow-up. CONCLUSIONS: Clusters derived from the EEG measures were not significantly associated with either neurocognitive or functional outcomes. P300 and n-back theta power may be associated with learning-related processes, which are important for acquisition and retention of skills during cognitive training programs. Future research should aim to identify at an individual level who is likely to respond to specific forms of cognitive enhancement.

Brief executive function training for individuals with severe mental illness: Effects on EEG synchronization and executive functioning.

BACKGROUND: Executive Functioning (EF) is an important factor for community functioning for people with severe mental illness. Cognitive remediation programs often improve EF, but do so by using multiple therapeutic techniques. Little is known regarding how individual treatment elements promote cognitive improvement. Oscillatory brain activity is a potential neurophysiological mechanism that may change as a result of targeted training on computerized exercises. The current study aimed to examine the effects of a brief EF training program on EEG and neurocognitive measures. METHODS: 25 people with severe mental illness were randomized to either 2weeks of computerized EF training or control training. Training consisted of 1h training sessions 3 times per week and 40min of daily home training. Assessments examined EEG theta and alpha band oscillatory power during EF tasks and neurocognitive measures of EF. RESULTS: EF training resulted in greater frontal theta power and reduced posterior alpha power during computerized EF tasks than control training. Power in the alpha frequency band over frontal electrode sites did not significantly differ between the two groups as a result of training. Additionally, participants in the EF training experienced significantly greater improvement in EF ability as measured by neurocognitive tests than the control condition. CONCLUSIONS: Two weeks of EF training is sufficient to produce neurophysiological and neurocognitive change. Frontal theta power and posterior alpha power may be important neurophysiological markers to consider in cognitive remediation studies, and the addition of a brief executive function training procedure to other psychosocial interventions is worth examining.

The score distribution and factor structure of the Community Assessment of Psychic Experiences-Positive Scale (CAPE-P15) in a Canadian sample.

AIM: Psychotic-like experiences (PLEs) share several risk factors with psychotic disorders and confer greater risk of developing a psychotic disorder. Thus, individuals with PLEs not only comprise a valuable population in which to study the aetiology and premorbid changes associated with psychosis, but also represent a high-risk population that could benefit from clinical monitoring or early intervention efforts. METHOD: We examined the score distribution and factor structure of the current 15-item Community Assessment of Psychic Experiences-Positive Scale (CAPE-P15) in a Canadian sample. The CAPE-P15, which measures current PLEs in the general population, was completed by 1741 university students. RESULTS: The distribution of total scores was positively skewed, and confirmatory factor analysis indicated that a 3-factor structure produced the best fit. CONCLUSION: The CAPE-P15 has a similar score distribution and consistently measures three types of positive PLEs: persecutory ideation, bizarre experiences and perceptual abnormalities when administered in Canada vs Australia.