Muscle tone: objective evaluation of the static component at the wrist.

A device measuring the flexion of the hand from an extended position was evaluated as a technique for assessing the passive component of muscle tone. Wrist measurements of 23 individuals, ten able-bodied, eight with spastic and five with flaccid wrists, were collected for three days of each week for three weeks, to determine the interrater, test-retest reliability, and construct validity of the device. Findings demonstrated high interrater reliability, inadequate test-retest reliability for single daily score comparisons, but an acceptable level of test-retest reliability for composite weekly score comparisons. Construct validity was supported since measurements of the involved limbs of individuals with spastic and flaccid wrists and the able-bodied group were significantly different from each other. This technique may provide useful objective information for therapists.