H-reflex is a kind of late response which can be used in the proximal nerve conduction study, especially in the diagnosis of S1 radiculopathy of the lower extremity. H-reflex is also noted in the flexor carpi radialis muscle of the upper extremity and can be used in the diagnosis of cervical radiculopathy. But H-reflex in other muscles of upper extremity is not commonly studied yet. The FCR, ECR and ADQ H-reflex study was performed in 20 normal adults (40 cases) and the 20 patients with cervical radiculopathy to establish the normal values and evaluate the significance of the upper extremity H-reflex study in cervical radiculopathy.

The mean values of H-reflex latency in normal control group were 17.45±3.11 msec in FCR, 18.57±5.22 msec in ECR and 26.23±1.55 msec in ADQ. And the mean value of the side-to-side difference were 0.74±0.44 msec in FCR, 0.51±0.37 msec in ECR and 0.51±0.37 msec in ADQ. The mean value of interlatency time (ILT) were 14.95±3.08 msec in FCR, 14.72±5.75 msec in ECR and 23.35±1.77 msec in ADQ. And the mean value of the side-toside difference were 0.52±0.37 msec in FCR, 0.45±0.42 msec in ECR and 0.56±0.40 msec in ADQ.

A study of the upper extremity H-reflex in 20 patients with cervical radiculopathy revealed abnormal H-reflex findings in 9 patients among 12 patients, which showed abnormal spontaneous activity in only the paracervical muscles and in 8 patients among 8 patients, which showed abnormal spontaneous activity in the paracervical and the upper extremity muscles.

H-reflex study in the upper extremity would be helpful to diagnose cervical radiculopathy.