Auditory event-related potentials, auditory digit span, and clinical symptoms in chronic schizophrenic men on neuroleptic medication.

The aim of this study was to test predictions based on Grossberg's theories of overarousal in neural networks as related to schizophrenic symptomatology. We predicted that symptoms of blunted affect and volition would be associated with reduced P300 amplitude, while impaired attention and short-term memory and symptoms of disorganization would be associated with increased N200 and P300 latency. Event-related potentials, elicited by auditory stimuli, were recorded in 20 chronic schizophrenic men on neuroleptic medication and an age- and sex-matched control group of 20 normal volunteers. The amplitude and latency values of the N200 and P300 waves at the vertex (Cz) were compared with clinical ratings (the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms) and with neuropsychological test scores by means of Spearman rank correlation coefficient. The patients showed a reduced P300 amplitude and an increased N200 latency. No correlation was found between the P300 amplitude and the symptom scores. The N200 latency was negatively correlated with auditory digit span and positively correlated with high global scores for attentional impairment, alogia, and positive formal thought disorder. Our initial predictions are partly confirmed by the apparent association between increased N200 latency and symptoms of disorganization.

A progression in the neuropsychological decline of Icelandic patients with probable or possible dementia of the Alzheimer's type: a longitudinal study.

To investigate the nature and rate of cognitive decline in dementia of the Alzheimer's type (DAT), 44 patients with probable or possible DAT (mean age 73.9, range 59-87 years) were given a comprehensive neuropsychological assessment. Twenty-five patients were retested 6 months later, and 11 were tested for the third time another 6 months later. Some tests of mental flexibility and double conceptual tracking ability were beyond the capabilities of the patients, and were left out of the statistical analysis because of floor effect. Poor initial performance on tests of attention, concentration, response speed, general cognitive ability, verbal memory, constructional skills, and perceptual closure ability resulted in nonsignificant changes over time (paired t tests). Tests of expressive speech, visuoperceptual functions and nonverbal memory, on the other hand, showed a significant deterioration over time. These findings indicate that when patients with DAT first receive medical attention, many neuropsychological functions are so severe impaired that there is little room for further decline. To describe the longitudinal course of cognitive decline in DAT, tests should be limited to those that assess the more resistant cerebral functions, and are more sensitive to progressive changes.

[Epidemiological study on cognitive abilities in the elderly in two separate rural areas in Iceland.].

OBJECTIVES: This study was undertaken to estimate the cognitive abilities in an elderly population in rural areas in Iceland and to get an idea of the prevalence of dementia. By examining inhabitants in two different areas it was further possible to detect any possible difference in these areas. MATERIAL AND METHODS: All persons aged 70 and over, living independently in the community and in institutions in two geographically separate areas were contacted. The areas were an agricultural (area A) and a fishing (area F) one. Four simple neuropsychological tests where used, the MMSE (Mini Mental State Examination), WAIS (Wechsler Adult Intelligence Scale)-Similarities, Trail making test A and Trail making test B. Two students in psychology and a teacher were trained in applying the tests but the results were scored and interpreted by the authors. RESULTS: In area A, 280 of 353 (79.3%) participated and in area F, 190 of 238 (79.8%). Participation was thus similar in both areas. There was a highly significant difference in all the tests with p<0.01 in Trail making test B but p<0.001 in the other three tests. In all the tests the results were better among the population in area A. The prevalence of dementia as estimated by the MMSE showed a prevalence of 14.4% in area A and 35.7% in area F. CONCLUSION: A significant difference in cognitive abilities was found between the elderly inhabitants of two separate rural areas in Iceland. There is substantial evidence to suggest that this difference is real but it is however not clear if the prevalence of dementia is higher in this study than in others. It is postulated that the difference found is due to cultural differences.