Use of Visual Force Feedback to Improve Digit Force Direction During Pinch Grip in Persons With Stroke: A Pilot Study
By Seo, Na Jin; Fischer, Heidi W.; Bogey, Ross A.; Rymer, William Z.; Kamper, Derek G.; Archives of Physical Medicine and Rehabilitation, Vol. 92, No. 1, pp. 24-30Publication Date: January 2011
Study investigated whether visual feedback of digit force directions for the index fingertip and thumb tip during repeated practice of grip force production can correct the digit force directions for persons with stroke during grip assessments. The study was conducted in light of the observation that following stroke, the paretic fingers generate digit forces with a higher than normal proportion of shear force to compression force during grip, leading to failure to grasp an object securely. Participants were 11 persons aged 38 to 69 years with chronic hemiparesis subsequent to stroke. Interventions comprised 4 training sessions and 2 evaluation sessions. Training consisted of controlling forces applied by the paretic thumb and index finger to an instrumented object composed of 2 independent plates, each connected to a miniature load cell. The load cells measured the 3-dimensional forces applied by the thumb and index finger separately. Visual feedback in the form of 2 glasses of water was displayed on a computer screen. Shear forces were mapped to the glass location and normal shear force was represented as the water level in the glass. Digit force direction during pinch and clinical hand function scores were measured before and immediately after training. Participants were able to redirect the digit force closer to the direction perpendicular to the object surface and increase their hand function scores after training. The mean ratio of the shear force to the normal force decreased from 58 percent to 41 percent, the mean Box and Block test score increased from 1.4 to 3.4, and the mean Action Research Arm Test score increased from 10.8 to 12.1.
Published by: W.B. Saunders Company, a division of Elsevier Health Sciences (Website:http://us.elsevierhealth.com)
American Academy of Physical Medicine and Rehabilitation (Web Site: http://www.aapmr.org/ )
American Congress of Rehabilitation Medicine (Web Site: http://www.acrm.org )
This publication is included in the library of the National Rehabilitation Information Center (NARIC), accession number J60532
