Hand Lab Grants

Whitaker Foundation

“Neural Control and Mechanics of Impaired Hand Function in Stroke”—Impairment of finger and hand function is a common problem following stroke, often resulting in chronic functional deficits.  Extension, abduction, and adduction of the fingers are particularly impaired, leaving the fingers in a flexed finger posture.  A number of different mechanisms could promote these deficits, with each suggesting a different modality of treatment. Knowledge of the underlying sources of impairment would provide great benefit in guiding rational treatment. Our first aim entails the development of a three-dimensional dynamic model of the index finger, in which this digit is used as a prototype for the other four fingers. The second aim of this proposal is to quantify the functional workspace of the hand and fingers in hemiparetic individuals in relation to the level of clinical impairment using the index finger as a representative case.

Department of Veteran's Affairs Grant

“Origins of Exaggerated Finger Flexion in Stroke”—Following acute hemispheric stroke, there is usually weakness of the contra lateral limbs (hemiparesis), which preferentially affects the upper extremity, especially the muscles acting around the wrist and in the hand.  While there is typically progressive improvement in muscle strength and motor function of proximal muscles over the ensuing weeks, hand impairment routinely persists, sometimes permanently.  These impairments are quite disabling, and may severely limit the stroke survivor’s capacity to function independently, to dress him/herself, or to return to work.  Our objective is to quantify the mechanical characteristics of hand impairment in stroke, and to address the origins of abnormal hand posture and of the impaired motor coordination.  This includes: quantifying spasticity in the long finger and hand muscles, examining the effects of muscle shortening and other changes in intrinsic muscle properties on postural deformity of the hand and wrist, and evaluating the role of weakness in the forearm and intrinsic muscles in promoting motor incoordination.

Rehabilitation Engineering Research Center

“Rehabilitation of Finger Extension in Chronic Hemiplegia”— Arm function is acutely impaired in a large majority of those diagnosed with stroke, with approximately one-third of all patients experiencing chronic hemiparesis.  These chronic deficits are especially prevalent in the distal upper extremities.  This distal limb impairment is especially problematic, because proper hand function is crucial to manual exploration and manipulation of the environment.  In addition, loss of hand function is a major source of disability in stroke, preventing effective self-care by the stroke survivor and limiting return to work. The goal of this research is to develop rehabilitative devices to therapeutically facilitate finger extension in individuals with chronic hemiplegia subsequent to stroke.  Two devices, one body-powered and one externally powered, will be produced and their efficacy tested.  The devices will supplement finger extension when necessary so that the desired hand motion can be achieved. 

Rehabilitation Research and Training Center

The overall project develops and evaluates a sequence of robotic training and assistive devices that are designed with the idea of promoting efficient function in the workplace or at home. Furthermore, this project will form a basis for the development of appropriate technologies to allow people with disabilities ready access to existing facilities. The goal of this portion of the project is to develop an orthotic system to facilitate reaching and grasping in individuals with hemiplegia subsequent to stroke.  The arm orthosis will provide compensation for gravitational loading of the arm, thereby reducing the force necessary to move the arm.  The hand orthosis will bias the hand toward an extended posture to compensate for excessive active flexor tone.  A fixed wrist orthosis will maintain a constant wrist angle.  The system will be comprised of entirely passive components, so that it can readily be used in home, community, or work environments.  Efficacy testing will be performed first in a laboratory setting, where changes in reaching and grasping performance resulting from use of the orthotic system can be rigorously quantified.  If warranted, further studies will then be conducted to assess the effects on function and daily living.