Six-minute walk distance in persons with Parkinson disease: a hierarchical regression model.
OBJECTIVE
To determine the six-minute walk distance (6MWD) in subjects with Parkinson disease (PD) and to determine the impairments that contribute to walking capacity.


METHODS
Descriptive cross-sectional study of subjects with PD.


METHODS
University laboratory.


METHODS
Subjects with PD (N=75; 65.0+/-9.5y) of mild to moderate severity, as defined by an average Hoehn and Yahr (HY) rating of 2.0+/-0.4 and Unified Parkinson Disease Rating Scale (UPDRS) motor score of 27+/-8.9, were tested on medication.


METHODS
Not applicable.


METHODS
Subjects were administered the motor subsection of the UPDRS and completed the following tests: Berg Balance Scale (BBS), Timed Up & Go (TUG), and six-minute walk test. In addition, they also provided self-reports of freezing of gait and number of falls in the past 6 months.


RESULTS
The average 6MWD was 391.6+/-99.9 m. All of the aforementioned tests, with the exception of fall number (P=.07), correlated significantly with 6MWD (r range, -.64 to .55). By using a hierarchical regression model, we entered age, HY, and UPDRS motor score into the first block (ie, set of independent variables) to represent parkinsonian characteristics, which explained a significant amount of variability in 6MWD (R2=.196, P<.001). The second block entered (eg, functional measures scores, self-reports) explained a significant amount of additional variability (R2 change=.355, P<.001). The TUG, BBS, and number of falls contributed independently in the presence of all independent variables.


CONCLUSIONS
The 6MWD in subjects with PD is explained in part by disease-specific characteristics and perhaps to a greater extent by impaired balance and predisposition to falling. Training targeted at improving balance and reducing falling risk factors may increase 6MWD (ie, walking capacity) in subjects with PD.
Falvo
Michael J
MJ
Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO 63108, USA.
Earhart
Gammon M
GM
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D012044:Regression Analysis; D012720:Severity of Illness Index; D016138:Walking