Support-specific modulation of grip force in individuals with hemiparesis.

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.