The effect of acupuncture on spinal motor neuron excitability in stroke patients

Spasticity is a common symptom in stroke patients, and its management constitutes a major problem in their rehabilitation. Acupuncture has been applied with moderate effect; their has been clinical experience but little objective evidence to support its use. H-reflex recovery time and H recovery curve were quantitative methods applied to measure spinal motor neuron excitability. Acupuncture for stroke patients as treatment to spastic hemiparesis was studied to see the acupuncture effect on increased spinal motor neuron excitability in spasticity.

Sixteen stroke patients with spastic hemiparesis were collected to evaluate the therapeutic effect of acupuncture on their spinal motor neuron excitability. H-reflex recovery time and H recovery curve were applied as quantitative evaluations of spinal motor neuron excitability. Eleven age-matched normal volunteers were used as a control group.

The mean H-reflex recovery time of normal controls was 73.3 +/- 18.3 mesc; that of the sound-side limbs of stroke patients was 67.1 +/- 21.5msec. The difference was not significant statistically (p = 0.2). However, the mean H-reflex recovery time of the paretic limbs of stroke patients was 52.3 +/- 16.8 msec, significantly shorter than for the normal controls (p = 0.003). The mean H-reflex recovery time of the paretic limbs of stroke patients became 57.6 +/- 19.9 msec after acupuncture, significantly prolonged as compared with that before acupuncture (p = 0.03). The H recovery curve of the paretic limbs after acupuncture also approximated that of the normal controls.

This result provides positive evidence of increased spinal motor neuron excitability in paretic limbs of stroke patients and also of the acupuncture effect which decreased that excitability. The study also presents a simple and practical technique for measuring the effects of various types of treatments, including acupuncture, on other types of central nervous system disorders.