Static postural stability as a new objective measure to understand how exercise rehabilitation programs improve Parkinson's disease

Abstract

The Sensory Attention Focused Exercise (PD SAFEx) program has previously been shown to be an effective intervention for reducing the motor symptoms (UPDRS III scores) of Parkinson’s disease (PD).  Although the UPDRS III is considered to be the gold standard for the assessment of disease severity in PD, exercise interventions may provide benefits that the clinician-based subjective UPDRS III cannot detect.   The aim of this study was to use objective measures to determine if a 12 week, 36 session PD SAFEx program improved postural stability in PD patients.  Subjects (n=36) stood with feet shoulder width apart, in quiet stance, under two conditions (i) eyes open, and (ii) eyes closed.  Total path length and mean velocity of a centre of mass estimate (COMe) were used as outcome measures.  In addition to the anticipated UPDRS III improvements, subjects significantly reduced their total COMe path length in both the eyes open [f(1,35)=8.67, p<.01], and eyes closed [f(1,35)=4.82, p<.05] conditions at post test.  Mean velocity of the COMe was also significantly reduced in both eyes open [f(1,35)=8.44, p<.01], and eyes closed [f(1,35)=5.30, p<.05] conditions.  These improvements indicate a greater ability to maintain stable posture in quiet stance as a result of the intervention.