engleski

A single case examination of a distinct subtype of schizophrenia

Aims/Background Hallmayer et al. (2005) recently identified a homogeneous subtype of schizophrenia characterized by pervasive cognitive deficit (CD), which appears to have a distinct genetic basis. The aim of this report is to present a single case approach to further characterize the cognitive performance of individuals identified as belonging to the CD subtype. Methods Individual performance variability was examined across a battery of cognitive tests in terms of: 1) the percentage of individuals classified with abnormally low scores, 2) the number of individuals with multiple, single or no cognitive deficits and 3) scatterplots of individual scores on immediate memory. Results All CD patients, except one, were impaired in their immediate recall of words, gaining an average of only 2.8 words across trials, compared with 4.9 words in healthy controls with lower verbal memory ability. Over 90% showed impaired current intelligence ; all CD patients had at least 3 cognitive deficits and approximately one third had deficits on all seven cognitive tests. In contrast only 76% were classified with abnormal performance on verbal fluency. Conclusions In the CD subtype verbal memory impairment is the most consistently observed cognitive deficit. Multiple (3+) cognitive deficits were exhibited by all CD cases and estimated current IQ was also low in the majority of these patients. Consequently, generalized cognitive deficiency appears to be a valid term to describe the cognitive characteristics of this subtype. However, executive dysfunction may not be essential to the CD subtype since approximately one quarter of patients were unimpaired in this domain.

schizophrenia; cognition; verbal memory

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