Continuous motion sensor assessment of Parkinson's disease during activities of daily living

OBJECTIVE: To use motion sensors to capture tremor, mobility, and dyskinesia in patients with Parkinson’s disease (PD) and motor fluctuations during activities of daily living. BACKGROUND: Tremor, bradykinesia, mobility, and dyskinesia have been measured previously using body worn motion sensors. However, quantification during unconstrained activities poses a unique challenge since dyskinesias can be difficult to distinguish from voluntary movement. DESIGN/METHODS: Eight subjects with PD and a history of levodopa-induced dyskinesias were instrumented with six degree-of-freedom motion sensors on the wrist and ankle. Data were recorded as subjects completed a series of activities of daily living (ADL) at stations set up in a simulated home environment for approximately two hours. Subjects first performed the activities in the OFF medication state and then took their usual prescribed dose of medication and continued to rotate through the ADL stations. Data recording sessions were videotaped for subsequent blinded clinical scoring. Time and frequency domain algorithms based on previous data were applied to generate severity scores for tremor and dyskinesia every 12 seconds. Moving average filters were applied to identify transitions in medication state. Dyskinetic periods were those for which dyskinesia score exceeded an empirically-determined threshold. RESULTS: Algorithm scores for tremor and dyskinesia showed a high level of agreement with annotations based on visual inspection of the video recordings and changed in concert with medication state. Tremor and dyskinesia scores were predictive of the presence or absence of tremor and dyskinesia, with average sensitivity and specificity greater than 90[percnt]. CONCLUSIONS: A system with two motion sensors can provide accurate measures of overall tremor and dyskinesia as patients complete complex movements associated with typical activities. Such a system could provide valuable insight on motor fluctuations in the context of daily life and aid in the development and evaluation of new therapies. Study Supported by: NIH/NIA 5R44AG044293-04 Disclosure: Dr. Pulliam has received personal compensation for activities with Great Lakes NeuroTechnologies. Dr. Heldman has received personal compensation for activities with Great Lakes NeuroTechnologies as an employee. Dr. Brokaw has received personal compensation for activities with Great Lakes NeuroTechnologies as an employee. Dr. Burack has received research support from Cleveland Medical Devices Inc. Dr. Mera has received personal compensation for activities with Great Lakes NeuroTechnologies as an employee.