Relations between on-off phenomena and cognitive functions in Parkinson disease.

10 patients with Parkinson disease on long term levodopa therapy and with fluctuations in motor performance unrelated to drug administration (on-off phenomena) were assessed on the following neuropsychological tests during the on and off phases: tests of attention (Toulouse-Pieron), memory (Digit Span, Rey forms 1 and 2), psychomotor capacity (maze test, single and multiple choice reaction times) and mood (Maudley Adjective Check List). The extrapyramidal symptoms were assessed on the Webster Rating Scale. We found no significant differences in attention, cognitive performance or mood between the on and off phases despite large fluctuations in motor performance.