Visual function in Huntington's disease patients and presymptomatic gene carriers.

Disturbances of visual cognition, visuomotor performance, and visual memory have been described frequently in Huntington's disease (HD). Early stage visual abnormalities could contribute to these deficits. We evaluated visual processing in 20 control subjects who were non-gene carriers at risk for HD, nine presymptomatic gene-positive subjects, and eight subjects with a recent diagnosis of Huntington's disease. Visual perceptual tests of contrast sensitivity and motion discrimination were used to probe early stage visual processing. Extraocular movements were evaluated in a neurologic examination, and the Digit Symbol test was used to test visual motor performance. Contrast sensitivity did not differ among the three groups. Motion discrimination was impaired in HD subjects but not in the presymptomatic gene carriers when compared to gene noncarriers. Among gene carriers, impaired motion discrimination performance was associated with poorer Digit Symbol performance and extraocular abnormalities. These findings suggest that the early stages of HD are associated with disturbances of motion perception as well as disruptions of visual motor and ocular motor performance.

Psychometrically matched visual-processing tasks in schizophrenia spectrum disorders.

Patients with schizophrenia show deficits in visual perception and working memory, but the relationship between these deficits has not been characterized with psychometrically matched tasks. The authors administered 2 visual discrimination and 6 recognition tasks to 43 schizophrenia spectrum patients and 22 nonpsychiatric subjects. When performing difficulty-matched tasks, spectrum subjects showed more severe impairments for motion compared with form processing. When tasks were matched on true score variance, spectrum subjects exhibited worse performance on both form and motion discrimination, and a differential deficit in motion recognition with a short display duration and long interstimulus interval. These results provide evidence of differential deficits in visual processing in schizophrenia that appear to be dependent on the temporal characteristics of the tasks.

Personality dimensions in schizophrenia: associations with symptoms and coping.

While individual differences in personality exist among persons with schizophrenia and predate the onset of illness, less is known about their relationship to outcome. This study examined whether levels of three personality dimensions-neuroticism, extraversion, and agreeableness-are associated with symptomatology and coping in persons with schizophrenia. Symptom, personality, and coping measures were obtained for 59 participants with schizophrenia. Personality and coping measures were obtained for 17 persons in a community comparison group. Relative to the community comparison groups, participants with schizophrenia had higher levels of neuroticism, lower levels of extraversion and agreeableness, and tended to employ more avoidant styles of coping. Participants with schizophrenia who had higher levels of neuroticism had greater positive and emotional discomfort symptoms and greater preferences for avoidant coping strategies. Participants with schizophrenia who had higher levels of agreeableness had lower levels of positive and excitement symptoms. No links were found between extraversion and outcome measures. Implications for understanding how personality may affect outcome are discussed.

Visual processing and neuropsychological function in schizophrenia and schizoaffective disorder.

Persons with schizophrenia and schizoaffective disorder exhibit deficits in both visual processing and neuropsychological tasks. Little is known, however, about whether these deficits are related to one another. We administered psychophysical tests of visual discrimination and recognition, and neuropsychological tests of abstract flexibility, verbal learning, visual memory, working memory and attention to 42 outpatients with stable but chronic schizophrenia or schizoaffective disorder. Multiple regression analyses were performed to determine the relationship between these measures of neuropsychological function and visual psychophysical performance. Results indicated that motion perception was associated with working memory, and that the addition of a memory component to motion perception (motion recognition) was associated with both working memory and visual memory. Visual performance was not associated with symptom severity as measured by the PANSS. These results suggest that psychophysical tests of visual processing may contribute to deficits on neuropsychological tests of visual cognition, and may also reflect cross-modal disturbances of working memory function.