The effect of shoulder subluxation on the electrophysiological characteristics of the peripheral nerves in the upper limbs of stroke survivors: A self-controlled study / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of shoulder subluxation on the peripheral nerves in the hemiplegic upper limbs of stroke survivors.Methods:Twenty stroke survivors with shoulder subluxation were enrolled. Conduction in their suprascapular, axillary, musculocutaneous, radial, median and ulnar nerves was monitored and needle electromyography was used to monitor activity in the supraspinatus, deltoid, biceps brachii, extensor digitorum, abductor pollicis brevis and abductor digiti minimi muscles of their affected upper limbs at rest. Upper limb and hand function were assessed using the Brunnstrom scale. The rate of change in the amplitude of the compound muscle action potentials (CMAPs) was correlated with the patient′s disease duration, age, and upper limb and hand Brunnstrom stages.Results:Compared with the healthy side, a significant decrease was observed in the CMAP amplitudes of the suprascapular, axillary, musculocutaneous, radial, median and ulnar nerves of the hemiplegic arm, and the latency of the suprascapular and axillary nerves was significantly prolonged. There was no inter-arm difference in the conduction velocity of the musculocutaneous, radial, median and ulnar nerves. The rates of change in the CMAP amplitudes of the suprascapular, axillary and musculocutaneous nerves were significantly higher than those of the radial, median and ulnar nerves. The sensory nerve action potential (SNAP) amplitudes of the median, ulnar and radial nerves on the hemiplegic side were significantly lower than on the healthy side, but there was no significant difference in the sensory conduction velocity between the two sides. On the hemiplegic side, the median nerve had the highest rate of change rate in the SNAP amplitude, followed by the radial and ulnar nerves, but there was no significant difference among them. Nor was there any significant difference in the rate of change in sensory nerve conduction velocity. The muscles of the affected upper limbs had higher potentials in the proximal than that in the distal nerves after shoulder subluxation. The rate of change in the CMAPs was not significantly correlated with a patient′s disease duration, age, or upper limb or hand Brunnstrom stage on the hemiplegic side.Conclusions:Shoulder subluxation after a stroke can cause greater damage to the peripheral nerves in the shoulder and upper arm than to those in the forearm and hand, possibly affecting the recovery of upper limb function.