A QUANTITATIVE STUDY OF LEVODOPA-INDUCED DYSKINESIA IN PARKINSONS-DISEASE

The present study addressed the question of whether the emergence and severity of levodopa-induced dyskinesia was related to the therapeutic benefits derived from levodopa. Eight PD patients with clinically obs erved levodopa-induced dyskinesia were studied prior to and for two ho urs following a single dose of Sinemet (carbidopa/levodopa). Quantitat ive instrumental procedures were used to assess upper extremity dyskin esia, rigidity and bradykinesia. Results indicated that all patients e xhibited significant reduction in their parkinsonism within 45 minutes following treatment. Reduction in bradykinesia, but not rigidity appe ared to coincide with the emergence of dyskinesia. There was a signifi cant relationship between severity of dyskinesia and the degree of imp rovement in movement velocity but not rigidity. Further analyses revea led that this relationship depended largely on the age of the patient. These findings are discussed as they pertain to a unified model of ba sal ganglia movement disorders which places dyskinesia and bradykinesi a at opposite extremes along a continuum.