Jamar hydraulic hand and pinch dynamometers

Motor function was assessed using multicomponent performance evaluations, which included composite measures of dexterity, gait, and hand strength.⁽²⁵, ²⁶⁾ The motor dexterity score was determined from the composite score of four trials, two trials per hand, using the Purdue pegboard and an electronic tapper (Western Psychological Services, Los Angeles, CA, USA). Motor gait was determined from the time and distance required to walk a distance of 8 feet and to turn 360 degrees twice. Motor hand strength was determined from grip and pinch strength assessments using the Jamar hydraulic hand and pinch dynamometers (Lafayette Instruments, Lafayette, IN, USA). Composite scores for each performance component were obtained by dividing by the sex‐specific median value at baseline, and a global composite was obtained by averaging across the performance evaluations.

We quantified ten motor tasks. (I&II) The Jamar hydraulic hand and pinch dynamometers (Lafayette Instruments, Lafayette) were employed to test bilateral grip and pinch strength. (III) Dexterity of the arms was based on the number of pegs placed in the Purdue Pegboard in thirty seconds. Two trials for each hand were averaged to provide a Purdue Pegboard score. (IV) An electronic tapper (Western Psychological Services, Los Angeles, CA) was employed to determine how quickly participants were able to tap with their index finger for ten seconds. Two trials for each hand were averaged to yield a tapping score. (V-VIII) We measured the time and number of steps taken to walk eight feet and turn 360°. (IX) Participant’s stood on each leg for ten seconds to assess lower extremity strength and balance. (X) Then they were requested to stand on their toes for ten seconds and the time standing was recorded^{37 (link),38 (link)}.
Composite measures reduce floor and ceiling effects and are suitable for modeling change over time. A summary global motor score was constructed by scaling and averaging all ten tests. In prior studies, a low score of this measure was associated with diverse adverse health outcomes including survival, incident disabilities and incident cognitive impairment^{38 (link),39 (link)}.