Mobility Therapy for Parkinsonism using Accelerometric Motion Analysis

Investigators: Eric E. Sabelman, PhD and Jonathan Katz, MD

Project Staff: Betty S. Troy, MS; Deborah E. Kenney, MS OTR; Douglas F. Schwandt, MS; Melinda Piper, MPT; Thomas Reiss, DPM; S.J. Weghorst, PhD; James Tetrud, MD; William J. Marks, MD; and Marsha Melnick, PhD, PT

Project Category: Other - 2000

Objective: In a series of Merit Review projects, we have created a Wearable Accelerometric Motion Analysis System ("WAMAS") able to quantify hitherto qualitative measures of human movement, with the goal of promoting independence and reducing risk of falls. In this proposal, we will use this instrument for correction of mobility impairments common to Parkinson's disease (PD) patients. We will measure motion patterns of individual PD patients performing tasks typical of activities of daily living, identify a customized combination of visual, auditory and/or tactile cues for informing the patient when his/her motion pattern deviates from the intended trajectory, conduct training sessions using real-time analysis of body acceleration to generate stimuli to promote successful completion of the task (i.e.: "unlock" freezing episodes), and finally, re-test subjects to determine residual effects of training. For example, we will attempt to correct abnormal gait cadence by flashing lights on the sides of eyeglass frames next to the accelerometer assemblies; with the WAMAS, flash frequency can be proportional to the wearer's stride and vary on left and right sides if the wearer attempts to turn a corner, unlike fixed-frequency visual stimulation. We hypothesize that synchronizing the frequency of stimuli with the motion pattern will improve function compared to random or unsynchronized stimuli. The subject population will include PD patients of varying degrees of severity, with and without medication (e.g.: L-DOPA), and pre- and post-surgery (e.g.: pallidotomy), as well as age- and gender-matched controls.

Research Plan:

1. Construct stimulation modules for the WAMAS - The sensory cues will include: Audible output of tones similar to a metronome and spoken phrases, Visible light patterns from light-emitting diodes (adapted from visual stimulation devices originated by Thomas Riess, who has Parkinson's himself, and further developed by Suzanne J. Weghorst of the University of Washington), Tactile stimulation devices consisting of motor-driven vibrators over tendons involved in the particular tasks.

2. Enroll human subjects - 50 subjects will be tested at VA Palo Alto HCS by Drs. Katz and Sabelman, primarily to refine the protocol for matching stimuli to individual motion patterns. Twenty subjects will be re-tested to establish transient effects of medication while they are participating in the experiment (James Tetrud, MD). A cohort of 20 post-pallidotomy patients will be included (William J. Marks, Jr., MD, & Marsha Melnick, PhD PT).

3. Perform subject testing with and without stimulation - The present battery of standing, walking and reaching activities will be expanded to include combined tasks involving transitional movements commonly inciting motor block in PD patients. Initial trials analyzed to deduce acceleration patterns for start and timing of stimuli from modules plugged into the WAMAS. In later training sessions, tasks will be repeated with an individualized combination of sensory stimuli.

4. Evaluate effect of therapeutic feedback during repeat training sessions and a follow-up session 2 to 4 weeks after end of training, using stimuli (a) synchronized with the intended motion, (b) desynchronized but cyclic, (c) randomly generated or (d) absent. Evaluation criteria will be reduction in reaction time, smoother motion, number of freezing episodes, waste motion and transition time between tasks. This test will study the extent of learned improvement in movement smoothness vs. continued input of WAMAS cues.

Funding Source: VA RR&D Merit Review

Funding Status: In Review