BradyXplore: Bradykinesia Feature Extraction System

Period of Performance: 09/30/2009 - 08/31/2010


Phase 1 SBIR

Recipient Firm

Cleveland Medical Devices, Inc.
Principal Investigator


DESCRIPTION (provided by applicant): The objective is to design, implement, and clinically assess a portable, user worn, bradykinesia feature extraction system, BradyXplore", for easy integration with CleveMed's existing ParkinSense" technology platform. Idiopathic Parkinson's disease (PD) and other parkinsonian disorders affect millions of people. Three major symptoms responsible for functional disability and reduced quality of life include tremor, bradykinesia, and rigidity. The current standard in evaluating symptoms is the Unified Parkinson's Disease Rating Scale (UPDRS), a subjective, qualitative ranking system. While tremor is often the most visible symptom, bradykinesia can be the most impairing to the patient. Objectively quantifying bradykinesia would aid in evaluating treatment protocol efficacy. More specifically, UPDRS scoring instructions for bradykinesia integrates multiple features into a single score that may cause increased inter-rater variability in scores as well as limit the opportunity to explore if particular bradykinesia features are influenced by specific treatment protocols. CleveMed has previously developed a compact wireless system to quantify movement disorder symptoms called ParkinSense". This previously existing technology will serve as the hardware platform for this proposed program. In a clinical study, this system successfully demonstrated objective quantification of PD motor symptoms. Quantitative variables were processed and applied to algorithms to assess symptom severity. Algorithm outputs were highly correlated with clinicians'qualitative UPDRS scores for rest, postural, and kinetic tremor. While moderate results were also achieved for bradykinesia, this application addresses optimization of bradykinesia feature extraction including speed, amplitude, and rhythm. The UPDRS uses three tasks to evaluate bradykinesia severity on a 0-4 scale: finger taps;hand opening- closing;and pronation-supination. Patients are instructed to repetitively complete each task as fast and with as wide an excursion as they can. Clinician scorers are instructed to account for speed, amplitude, fatiguing, hesitations, arrests in movement, and how these variables change over time. Accounting for all of these variables is challenging, even for the most experienced movement disorder specialist. It is difficult to gauge weights specific clinicians place on different bradykinesia manifestations. Also, it is unclear if underlying neural mechanisms for different manifestations are the same. Objectively quantifying specific bradykinesia features should aid in the development of novel DBS therapies for targeting specific bradykinesia manifestations. Furthermore, a portable platform for more continuous monitoring will allow a clinician to capture complex fluctuation patterns in treatment response. PUBLIC HEALTH RELEVANCE: Parkinson's disease affects more than 1,000,000 people in the United States causing motor symptoms of which one of the most debilitating is bradykinesia (slowed movements). Bradykinesia is currently evaluated using a subjective rating scale that gives a single score taking into account speed, amplitude, fatiguing, hesitations, arrests in movement, and how these variables change over time. The proposed BradyXplore bradykinesia feature extraction system will separately quantify specific features of bradykinesia (speed, amplitude, and rhythm), which should aid in the development of novel therapies to target a patient's specific bradykinesia manifestations.