Comparison of prefrontal hemodynamic responses and cognitive deficits between adult patients with autism spectrum disorder and schizophrenia.

Autism spectrum disorder (ASD) and schizophrenia share many phenotypic characteristics, but their association with prefrontal function have not been directly compared. The aim of this study is to compare cognitive profiles and their association with the prefrontal function between the two groups. We explored prefrontal dysfunction among adult individuals with ASD (n = 32), schizophrenia (n = 87), and healthy controls (HCs; n = 50). We assessed cognitive function in all participants using the Brief Assessment of Cognition in Schizophrenia (BACS). The BACS data of patients with schizophrenia were entered into hierarchical cluster analyses to assign subjects to a specific subgroup based on individual profiles. Using near-infrared spectroscopy, we measured hemodynamic responses in the fronto-temporal regions during a working memory task. Among the patients with schizophrenia, we defined 4 neurocognitive subgroups, including a global impairment, a mild impairment, and 2 selective impairment groups. Compared to the HCs, the ASD and schizophrenia groups had much weaker hemodynamic responses in the left DLPFC, left frontopolar cortex (FPC), and left inferior frontal gyrus. The ASD group showed a similar level of cognitive impairment with the mild level subgroup of schizophrenia. Additionally, the two groups shared reduced activity in the left DLPFC and left FPC during the task compared to HCs. Moreover, the BACS composite scores correlated positively with hemodynamic responses in a broad area involving fronto-temporal regions in the total patient sample. This research indicates considerable similarity in the left PFC dysfunction and its association with cognitive deficits between the disorders. These findings may guide future studies that investigate pathophysiological similarities between ASD and schizophrenia.

Right Frontotemporal Cortex Mediates the Relationship between Cognitive Insight and Subjective Quality of Life in Patients with Schizophrenia.

Although prior studies identified a relationship between cognitive insight and subjective quality of life (QOL) in patients with schizophrenia, the brain regions mediating this relationship remain unknown. Recent studies have shown that the ventrolateral prefrontal cortex may be particularly important for cognitive insight in individuals with schizophrenia. Here, we examined whether frontotemporal function mediates the relationship between cognitive insight and QOL in 64 participants, including 32 patients with schizophrenia and 32 healthy controls. Cognitive insight was measured using the Beck Cognitive Insight Scale (BCIS), while participants' subjective QOL was assessed using the Medical Outcomes Study 36-item Short-form Health Survey. Frontotemporal function was evaluated during a verbal fluency task using multichannel near-infrared spectroscopy. Consistent with previous findings, we found that frontotemporal function was impaired in patients with schizophrenia. Interestingly, our data also revealed that the right ventrolateral PFC and the right anterior part of the temporal cortex significantly mediated the relationship between the self-reflectiveness (SR) subscale of the BCIS and subjective QOL. These findings suggest that cognitive insight, particularly SR, is associated with subjective QOL in patients with schizophrenia via right frontotemporal function. The findings of this study provide important insight into a QOL model of schizophrenia, which may guide the development of cost-effective interventions that target frontotemporal function in patients with schizophrenia.