THE ASSOCIATION BETWEEN CLINICAL AND QUANTITATIVE INDEXES OF PARKINSONIAN SYMPTOMATOLOGY

Motor impairments in Parkinson's disease (PD) have been characterized with clinical as well as experimental instruments. However, the degree of association between the two types of tasks has not been investigat ed directly. The diagnostic power and relevance of the clinical tools may be enhanced by knowing the degree to which they are sensitive to t he deficits in movement initiation, preparation, and execution charact erized in experimental tasks. We have developed a sequential button-pr essing task that is sensitive to PD patients' ability to initiate and execute individual movements as well as movement sequences, It has als o been used to assess patients' reliance on sensory cues and their abi lity to use advance information to facilitate movement. In the present study, 12 patients with PD were tested on the cued sequential button- pressing task. Performance measures were correlated with scores on thr ee widely used clinical rating scales (Webster, Hoehn and Yahr, Northw estern University Disability scales) and three standard clinical tests (Purdue pegboard, hand-tapping, walking). Results indicated that the standard clinical tests are sensitive to bradykinesia, while the ratin g scales were sensitive to deficits in movement initiation and executi on and the ability to use advance information in order to facilitate m ovement. Thus, it is suggested that a subset of clinical measures is s ensitive to underlying deficits in planning, initiation, and execution of movement.