The goal of this grant is to create a miniature, solid state device that can monitor, on a continuous, long-term basis, the motor activity of Parkinson's disease. Having a physiology monitoring system to quantify tremor and possibly other movements would be a needed contribution. The monitoring of motor activity continuously for 6 days will provide information regarding the patients activity levels; the duration and effectiveness of various treatment regimen, note and display frequency, duration and time of occurrence of on/off episodes describe the sleep patterns and awakenings; and correlate the recording with the patient's diary. We propose to develop the criteria for a solid state device and assemble a prototype and test it for clinical usefulness. To achieve these aims, reference methods in clinical use and multi-channel, ambulatory cassette tape recorders (Holter type) will be equipped with high fidelity tri-axial accelerometer to establish a standard. The data will be analyzed with FFT program and displayed and compared with data obtained from a wrist actigraph. The actigraph will be optimized with transducer and filter selection to meet the clinical criteria. Patients and normal, matched controls will be recorded and studied. In Phase II we will produce a number of motor activity actigraphs, test them on a large patient population and develop the software for a clinical report summarizing the data collected.