[Cognitive function and its evaluation methods in Parkinson's disease--a study including RCPM and ERP].

In order to investigate features of cognitive impairment in idiopathic Parkinson's disease (PD) and suitable methods for the cognitive evaluation of patients with PD, 23 PD patients and 15 normal control subjects were studied using neuropsychological tests and auditory event-related potential (ERP). The two groups did not differ from each other in age or education. Clinical severity of the patients based on Hoehn & Yahr's staging ranged from stage I to IV: 7 patients at stage I, 8 at stage II, 7 at stage III and 1 at stage IV. All patients achieved the Mini-Mental State test (MMS) scores of 24 or greater, and none of the patients showed middle or serious grade of dementia based on the Diagnostic and Statistical Manual of Mental Disorders-Third edition-Revised (DSM-III-R). All patients and controls underwent MMS, the Hasegawa's Dementia Screening Scale (HDS), the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Raven's coloured progressive matrices (RCPM), The Wisconsin Card Sorting Test (WCST) and the Benton Visual Retention Test (BVRT). Auditory ERPs by standard oddball paradigm (two-choice reaction time task) were elicited (band-pass 0.1-50 Hz) from Cz electrode sites on all subjects with a random series of binaural 1,000 (standard; 80%) or 2,000 (target; 20%) Hz tones presented every 2 sec at 70 dB SPL. In RCPM, N100 peak latencies of ERP (target and standard), performance-IQ of WAIS-R (especially block design and digit symbol subtests) and in error scores of BVRT there were striking differences between the two groups (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)