Support-specific modulation of grip force in individuals with hemiparesis

Abstract

Objective: To investigate whether use of auxiliary sensory input will result in modulated grip force.

Design: Case-control study.

Setting: Free-standing acute inpatient rehabilitation hospital.

Participants: Six people with unilateral hemiparesis due to unilateral stroke and 6 control subjects without neurologic disorders.

Interventions: Seated subjects lifted and transported the same object under 3 different conditions: with no support, with the target arm positioned on a freely moving skateboard, and with a finger from the subject's contralateral hand lightly touching the wrist of the target arm.

Main outcome measures: Peak grip force and temporal coupling between the grip force and lift-off of the object.

Results: All subjects were able to better regulate grip force when provided with additional sensory input. Light finger touch resulted in decreased grip force, as did skateboard use ( P <.05). Subjects with hemiparesis showed 2 times longer latency between grip-force application and lift-off of the object ( P <.05).

Conclusions: Statistically significant grip-force reduction was noted with both support aids. These findings could have implications in clinical and rehabilitative areas.