QUANTIFYING RIGIDITY WITH A NEW COMPUTERIZED ELBOW DEVICE

A new computerized method is described for measuring parkinsonian rigi dity with an elbow device. We present data from 127 subjects (103 cont rols and 24 parkinsonian patients) to show the clinical utility of the method. The instrumental quantification of rigidity correlates highly with clinical ratings of parkinsonian rigidity. The test-retest repea tability was excellent. In parkinsonian patients versus normal control s, significantly higher values of measured rigidity were observed. Mor eover, activation procedure significantly increases rigidity only in p arkinsonian patients. Activated rigidity in control subjects is lower than basal values. The procedure was sensitive to increased rigidity i n parkinsonian patients during 3 days' drug holiday. Contrary to previ ous reports, levodopa therapy reduced both basal and activated rigidit y in parkinsonian patients. This method is relatively simple and takes only 15 min to complete.