Muscle weakness in Parkinson's disease: a follow-up study

We compared isokinetic muscle strength between initial and subsequent measu rements in 10 patients who could repeat the same testing later among 23 pre viously described patients with Parkinson's disease. Patients were divided into two groups according to changes in clinical condition between the time s of the first and the subsequent measurements. For patients who had improv ed, both extension and flexion on the more affected side showed significant ly greater torque at 15 rpm in the later than the earlier measurement. For patients who had worsened, both extension and flexion on the more affected side showed significantly less torque at 5 and 15 rpm in the later than the earlier measurement. Although isokinetic muscle strength is likely to depe nd on movement velocity in the early stages of Parkinson's disease, it may be influenced by bradykinesia, as the disease progresses. Speed-force corre lation seen in these patients may give clues to the understanding of the pa thophysiology of bradykinesia. (C) 2001 Elsevier Science Ltd. All rights re served.