Impaired error monitoring contributes to face recognition deficit in schizophrenia patients.

BACKGROUND: It has been proposed that social and cognitive deficits in schizophrenia may result from impaired error monitoring. OBJECTIVE: We tested the hypothesis that among schizophrenia patients, impaired error monitoring contributes to poor face recognition, an important social skill. METHODS: 79 schizophrenia patients and 57 healthy individuals were administered a computerized face recognition test which allowed collection of accuracy and latency performance parameters. Error monitoring was assessed by analyzing reaction times for correct (RTC) and incorrect (RTI) responses. Tests of working memory (WM) and processing speed were also administered. RESULTS: RTI was longer than RTC in patients and controls and did not differ between the groups. RTC was significantly longer in patients than controls. Error monitoring effort, calculated by dividing the difference between RTI and RTC by the sum of RTC and RTI, was significantly smaller in patients than controls. A regression model with face recognition performance as dependent variable showed independent contributions of error monitoring effort, spatial working memory and group (patient/healthy) to test performance and explained 26.1% of the variance. CONCLUSION: Error monitoring function influences face recognition accuracy and is impaired in schizophrenia. Impairments in error monitoring, and spatial WM contribute to face recognition deficits in schizophrenia.

Evidence for sustained attention and working memory in schizophrenia sharing a common mechanism.

Sustained attention and working memory (WM) are closely related functions that may share common mechanisms. The authors assessed sustained attention in schizophrenia patients and healthy comparison subjects using visuomotor tracking tasks under varying distractor loads. The attentional effort expended to deal with distractors was lower in patients and showed significant association with WM, executive function and negative symptoms in that group. It is proposed that the anterior attention system of sustained attention models and the executive function of the WM model describe the same or a closely related mechanism that is located in the prefrontal cortex (PFC) and is impaired in schizophrenia.

Animal-assisted therapy ameliorates anhedonia in schizophrenia patients. A controlled pilot study.

BACKGROUND: Anhedonia, a component of the negative symptom dimension and a core phenomenon in schizophrenia, is associated with poor social functioning and is resistant to treatment. We tested the hypothesis that animal-assisted therapy (AAT) may improve anhedonia. OBJECTIVE: To compare the effect of psychosocial treatment sessions in which a dog was an active participant (AAT) with comparable sessions without a dog, using a controlled protocol. METHOD: The hedonic tone of 10 chronic schizophrenia patients who participated in 10 weekly interactive sessions of AAT was compared to a control group treated without animal assistance. The hedonic tone was measured with the Snaith-Hamilton Pleasure Scale. Subjective quality of life variables and clinical symptoms were also assessed. RESULTS: The AAT group showed a significant improvement in the hedonic tone compared to controls. They also showed an improvement in the use of leisure time and a trend towards improvement in motivation. CONCLUSION: AAT may contribute to the psychosocial rehabilitation and quality of life of chronic schizophrenia patients.

Working memory deficit as a core neuropsychological dysfunction in schizophrenia.

OBJECTIVE: This study tested the hypothesis that impaired working memory is a core deficit underlying multiple neuropsychological deficits in schizophrenia patients. METHOD: The subjects were 27 men with stable chronic schizophrenia treated with atypical antipsychotics and 38 normal participants. They were assessed with a battery of neuropsychological tests. Verbal working memory was measured with the WAIS digit span tests, and the Dot Test was used to test spatial working memory. RESULTS: In the patients, verbal working memory showed significant correlations with visual retention, visual orientation, simple motor function, visuomotor coordination, and executive function but not with memory for objects, memory for faces, recognition of facial emotions, or attention. Spatial working memory showed significant correlations with visual retention, visual orientation, memory for objects, memory for faces, and simple motor function but not attention, executive function, or visuomotor coordination. In the comparison group, no correlations between working memory and other neuropsychological functions were found. CONCLUSIONS: These findings support the hypothesis that working memory is a core deficit in schizophrenia. The authors postulate that the lower capacity for verbal and spatial "on-line storage" is rate limiting in the performance of other cognitive functions. Executive functions rely critically on the phonetic loop, complex visual functions such as object and face memory rely on the spatial on-line storage system (visuospatial scratch pad), while other functions such as visual orientation depend critically on both capacities.