title: The effect of moderate Parkinson's disease on compensatory backwards stepping.
abstract: Postural instability is a major unmet need in the treatment of Parkinson's disease (PD) and its progression is not well understood. This study examined compensatory stepping taken in response to a backwards waist pull in participants with moderate PD (H&Y III) compared to age-range matched healthy controls (HC). The first step in the response was quantified in terms of strategy, temporal, kinematic, and center of pressure (COP) parameters previously observed to be significantly different in mild PD (H&Y II) compared to HC. Patients with moderate PD, compared to HC, utilized more steps to regain balance, had a longer weight-shift-time, and utilized a base-width neutral step to regain balance. However, there were no differences in ankle angle or COP location at landing as observed in mild PD, possibly due to the use of the base-width neutral step. These results suggest that moderate PD significantly impairs the compensatory response to a backwards pull. Further study should examine the progression of impairment in compensatory responses across PD severity levels, and the correlation with fall risk.
authors.affiliation: The University of Kansas, 1530 West 15th Street, Room 3138, Lawrence, KS, 66045, United States.
authors.forename: Molly A
authors.initials: MA
authors.lastname: McVey
authors.forename: Sommer
authors.initials: S
authors.lastname: Amundsen
authors.forename: Annaria
authors.initials: A
authors.lastname: Barnds
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Lyons
authors.forename: Rajesh
authors.initials: R
authors.lastname: Pahwa
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Mahnken
authors.forename: Carl W
authors.initials: CW
authors.lastname: Luchies
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time
keywords: Balance; Balance recovery; Compensatory Stepping; Falls; Parkinson's disease