Journal of Rehabilitation Research & Development (JRRD)

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Volume 48 Number 5, 2011
   Pages 577 — 586

Abstract —  Evaluations of neuromuscular dynamics of hyperactive reflexes poststroke

Jie Liu, BS;1-3 Dali Xu, PhD;1,4 Yupeng Ren, MS;1 Li-Qun Zhang, PhD1-2,5*

1Rehabilitation Institute of Chicago, Chicago, IL; 2Department of Biomedical Engineering, Northwestern University, Evanston, IL; 3College of Engineering, Huazhong Agricultural University, Wuhan, China; 4Department of Kinesiology, Western Illinois University, Macomb, IL; 5Departments of Physical Medicine and Rehabilitation and Orthopaedic Surgery, Northwestern University, Evanston, IL

Abstract — Tendon reflexes are widely used in clinics to conveniently evaluate various neurological disorders. This study characterized neuromuscular dynamics of tendon reflexes at the elbow with multiple quantitative measures in both patients with stroke and nondisabled controls. We employed a handheld instrumented hammer to tap the triceps muscle tendon at various elbow flexion angles and measured the tapping force, triceps electromyography, and elbow extension torque to characterize neuromuscular dynamics of tendon reflexes quantitatively in terms of the tendon reflex gain, contraction rate, half relaxation rate, reflex loop delay, and reflex threshold in tapping force. We found that the tendon reflex gain, contraction rate, and half relaxation rate were significantly higher while the reflex threshold was significantly lower across different joint angles in patients with stroke than in nondisabled controls (p < 0.05), indicating hyperactive neurological state and muscle contraction dynamics poststroke. This study presents a convenient and quantitative method to evaluate reflex excitability and muscle contraction dynamics.

Key words: contraction rate, half relaxation rate, neurological disorder, reflex gain, reflex loop delay, reflex threshold, rehabilitation, spasticity, stroke, tendon reflex.

View HTML  ¦  View PDF  ¦  Contents Vol. 48, No. 5
This article and any supplementary material should be cited as follows:
Liu J, Xu D, Ren Y, Zhang LQ. Evaluations of neuromuscular dynamics of hyperactive reflexes poststroke.
J Rehabil Res Dev. 2011;48(5):577-86.

Last Reviewed or Updated  Wednesday, May 25, 2011 11:24 AM

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