MODALITY DEPENDENT CHANGES IN EVENT-RELATED POTENTIALS CORRELATE WITHSPECIFIC COGNITIVE FUNCTIONS IN NONDEMENTED PATIENTS WITH PARKINSONS-DISEASE

The relationship between event-related potentials (ERPs) and cognitive functioning was studied in patients with Parkinson's Disease (PD) but without dementia. Auditory and visual stimuli were used; 30 subjects participated in the auditory study and 20 in the visual study. Patient groups did not differ with respect to gender, age, education, illness duration, and level of cognitive functioning. Visual stimuli were 2.3 cpd sinusoidal grating patterns randomly presented in an oddball para digm (oblique vs. vertical spatial orientation). Auditory stimuli were tones presented at 70 dB SPL at a rate of 1.1/second, also using the oddball paradigm (1.5K vs. 1K tones). All patients were given neuropsy chological tests to measure verbal fluency, memory, visual spatial per ception, and abstract reasoning. P300 and N200 abnormalities correlate d with a number of these measures, such that longer ERP latencies were related to lower scores on tests of cognitive functioning. Patterns o f results suggest that auditory and visual ERPs correlate with differe nt subsets of neuropsychological functions in nondemented PD patients and that N200 may provide a new metric for clinical use.