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 the flexor carpi radialis H-reflex (FCR H-R) is not commonly studied yet. The FCR H-R study was performed in 40 normal individuals (80 nerves) and the 8 patients with C6 or 7 radiculopathy to establish the normal values and evaluate the significance of the FCR H-R study in cervical root lestion.

The result are as follow:

1) The mean value of the FCR H-R latency was 14.72±1.11msec. There was no significant differences between Rt. and Lt. side.

2) The side-to-side difference greater than 0.72msec was observed as abnormal value in FCR H-R latency.

3) The mean value of interlatency time (ILT) was 12.78±1.03msec. There was no significant differences between Rt. and Lt. side.

4) The side-to-side difference greater than 0.65msec was observed as abnormal value in ILT.

5) There is a significant correlation between FCR H-R latency and arm length.

6) A study of FCR H-R in 8 patients with C6 or 7 radiculopathy revealed prolonged latency in 2 patients, decreased amplitude in 2 patients, absent H-R in 1 patient.