BS in Physical Therapy and Rehabilitation Medicine, Vrije Universiteit Brussel, Brussels, Belgium
MS in Neurophysiology and Rehabilitation Medicine, Vrije Universiteit Brussel, Brussels, Belgium
PhD in Neurophysiology, Loma Linda University, Loma Linda, CA

Physiology and Neuroscience

Research in this lab is focused on understanding discoordination of the upper limb after stroke, in learning the involvement of brain plasticity in recovery, and in developing novel neurotherapeutic training programs to enhance motor control of the upper limb even years after a stroke.
Using multi-channel EMG and a 6 degree-of-freedom load cell, we can quantify discoordination in the impaired arm and begin to investigate the mechanisms underlying this reduction in muscle and torque combinations between the elbow and shoulder joints. One main objective is in understanding the relationship between the reduction in movement capabilities and brain reorganization. Determination of the nature of reorganization of motor cortices during controlled mechanical experiments in hemiparetic stroke subjects is expected to answer fundamental questions regarding brain plasticity and its effects on motor recovery.
Additional research interests involve the development of novel neurotherapeutic training programs using quantitative computer driven feedback that seek to improve the ability to produce necessary muscle and torque combinations for reaching and retrieval motions with the impaired arm. I am also planning some future work on pharmacological interventions that seek to alter spinal interneuronal bias. Abnormal interneuronal excitability is believed to be the source of altered spinal reflex activity following brain lesions and may very well be an important contributor to movement discoordination.

Basic mechanisms underlying discoordination following brain injury and the application to rehabilitiation following injury.

Dewald, JPA, Rymer, WZ, Schmit, BD. Reflex torque responses to multiple movement velocities in the spastic elbow: Evidence for changes in reflex threshold and gain. Submitted t Muscle & Nerve 2003.

Ricamato, AL, Dhaher, YY, and Dewald, JPA. Electrical cortical activity associated with joint torque direction in the human arm. Submitted to the Journal of Neurophysiology 2002.

Dewald, JPA, Beer, RF. Evidence for abnormal joint torque patterns in the paretic upper limb of subjects with hemiparesis. Muscle & Nerve 24 (2): 273-283, 2001.

Dewald, JPA, Sheshadri, V, Dawson, ML, Beer, RF. Upper limb discoordination in hemiparetic stroke: Implications for neurorehabilitation. Topics in Stroke Rehabilitation 8(1) 1-12, 2001.

Beer RF, Dewald JPA and Rymer WZ. Deficits in the coordination of multijoint arm movements in hemiparetic subjects. Evidence for disturbed control of limb dynamics. Experimental Brain Research 131 (3): 305-319, 2000.

Dewald, JPA, Beer, RF, Given JD, McGuire, J.R., and Rymer, WZ. Reorganization of flexion reflexes in the upper extremity of hemiparetic subjects. Muscle & Nerve. 22 1209-1221, 1999.

Beer, R.F, Dewald, J.P.A, Rymer, WZ. Disturbances of Voluntary Movement in Stroke: Problems of Planning or Execution? Progress in Brain Research 123: 455-60, 1999.

Beer, RF, Given, JD, Dewald, JPA. Task-Dependent weakness at the elbow in patients with hemiparesis. Archives of Physical Medicine and Rehabilitation. 80(7) 766-72, 1999.