Motoneuron pool excitability of hemiplegic patients: assessing recovery stages by using H-reflex and M response

Abstract

Objectives: To compare the excitability of the motoneuron pools of both the spastic and the unimpaired sides of patients with hemiplegia with a new method by using H-reflexes and M responses. The method determines the ratio of the developmental slope of the H-reflex (Hslp) to the slope of the M response (Mslp). We also examined the relation between the Brunnstrom stages and the Hslp/Mslp.

Design: Experiment.

Setting: Electrophysiologic experimental laboratory in a Japanese medical school.

Patients: Fifteen hemiplegic patients (9 men, 6 women; age range, 48-71yr; mean, 60yr) with spasticity caused by a stroke.

Interventions: The subject was instructed to relax while seated in a reclining chair with his foot fixed on an immobile pedal. After the soleus H-reflex and M responses on one side were recorded, the same experimental procedures were carried out on the other side.

Main outcome measures: Hslp/Mslp Brunnstrom stages.

Results: Hslp/Mslp had better predictive value than conventional indicators of motoneuron pool excitability. Hslp/Mslp appeared to be a better match for the bell-shaped pattern of the Brunnstrom stages.

Conclusion: Hslp/Mslp is the preferred index for evaluating the motoneuron pool excitability of the spastic side of hemiplegic patients.