Handgrip Strength Related to Long-Term Electromyography: Application for Assessing Functional Decline in Parkinson Disease.
OBJECTIVE
To determine which clinical measures of physical function (ie, gait, balance, and grip strength) best represent long-term electromyography in persons with Parkinson disease (PD) compared with those without PD.


METHODS
Cross-sectional study.


METHODS
Local community.


METHODS
A sample (N=37) of men and women with PD (n=23) and those without PD (n=14), living independently at home, older than 50 years of age, from the local community.


METHODS
Not applicable.


METHODS
Measures of gait, balance, and grip strength were completed, and electromyography was examined in biceps brachii, triceps brachii, vastus lateralis, and biceps femoris during a 6.5-hour day. Muscle activity was quantified through burst in electromyography (>2% of the normalized maximum voluntary exertion with a continuous activity period of >0.1s). Stepwise multiple regression models were used to determine the proportion of variance in burst characteristics explained by clinical measures of physical function in PD.


RESULTS
Grip strength was the best predictor of muscle activity in persons with PD (R2=.17-.33; P<.04), whereas gait characteristics explained muscle activity in healthy controls (R2=.40-.82; P<.04).


CONCLUSIONS
Grip strength could serve as an effective clinical assessment tool to determine changes in muscle activity, which is a precursor to functional loss in persons with PD.
School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada. Electronic address: gareth.jones@ubc.ca.
Gareth R
GR
Jones
Centre on Aging, University of Victoria, Victoria, British Columbia, Canada.
Kaitlyn P
KP
Roland
Department of Occupational Therapy, University of Alberta, Edmonton, Alberta, Canada.
Noelannah A
NA
Neubauer
School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada.
Jennifer M
JM
Jakobi
D000368:Aged; D003430:Cross-Sectional Studies; D004576:Electromyography / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology*; D026741:Physical Therapy Modalities; D004856:Postural Balance / Q000502:physiology; D012044:Regression Analysis
Activities of daily living; Clinical medicine; Independent living; Muscle relaxation; Muscle strength dynamometer; Rehabilitation