Paretic upper-limb strength best explains arm activity in people with stroke.

BACKGROUND AND
PURPOSE: The purpose of this study was to determine the relationship among variables of upper-limb impairment, upper-limb performance in activities of daily living (activity), and engagement in life events and roles (participation) in people with chronic stroke.
SUBJECTS: The subjects were 93 community-dwelling individuals with stroke (> or =1 year).
METHODS: This study, which was conducted in a tertiary rehabilitation center, used a cross-sectional design. The main measures of impairment were the Modified Ashworth Scale, handheld dynamometry, sensory testing (monofilaments), and the Brief Pain Inventory. The main measures of activity were the Chedoke Arm and Hand Activity Inventory (CAHAI) and the Motor Activity Log (MAL). The main measure of participation was the Reintegration to Normal Living (RNL) Index.
RESULTS: Paretic upper-limb strength (force-generating capacity) (r=.89, P<.01), grip strength (r=.69, P<.01), and tone (resistance to passive movement) (r=-.80, P<.01) were the impairment variables that were most strongly related to activity. Tone (r=-.23, P<.05) and CAHAI scores (r=.22, P<.05) had a significant, but weak, relationship to participation. Upper-limb strength accounted for 87% of the variance of the CAHAI scores and 78% of the variance of the MAL scores. In the participation models, tone and CAHAI scores accounted for 5% of the variance of the RNL Index scores. DISCUSSION AND
CONCLUSION: Paretic upper-limb strength had the strongest relationship with variables of activity and best explained upper-limb performance in activities of daily living. Grip strength, tone, and sensation also were factors of upper-limb performance in activities of daily living. Increased tone and upper-limb performance in activities of daily living had a weak relationship with participation.