H-reflexes in the Flexor Carpi Radialis with Facilitation and with Facilitation & Averaging: Normative Data

OBJECTIVE: To determine the normal values of flexor carpi radialis (FCR) H-reflex without facilitation, with facilitation and with facilitation & averaging. And to compare the three methods. METHOD: The FCR H-reflex was tested in 60 healthy people. 1) H-reflexes was recorded in the FCR muscle without facilitation. 2) H-reflexes was recorded in the FCR muscle with facilitation and facilitation was carried out by contracting the FCR muscle with 1 kg of weight. 3) FCR H-reflex was tested by repetitive stimulation with facilitation and the multiple responses were averaged. RESULTS: Without facilitation, FCR H-reflexes were elicited only in 24 people out of 60 people and with facilitation, FCR H-reflexes were elicited in all 60 people. The mean latencies and amplitudes of the three methods were measured and normal limits of latency difference and amplitude ratio were calculated. In the FCR H-reflex without facilitation, with facilitation and with facilitation & averaging, the normal limits of latency difference were 1.0 msec, 1.0 msec, 1.1 msec and normal limits of amplitude ration were 0.37, 0.22, 0.57. CONCLUSION: FCR H-reflex with facilitation and with facilitation & averaging might be useful in the clinical diagnosis.

The Utility of 6 cm Segmental NCS in Ulnar Neuropathy at the Elbow

OBJECTIVE: To verify the efficacy of 6cm segmental nerve conduction study in ulnar neuropathy at the elbow (UNE). METHOD: Ulnar nerve conduction studies were performed unilaterally in twenty five asymptomatic healthy adult volunteers and twenty five symptomatic patients with UNE. Twenty five symptomatic patients with UNE were diagnosed by standard ulnar nerve conduction studies, and needle EMG study. In the same healthy controls and patients groups, 6 cm and 10 cm segmental study were then performed at the elbow. The sensitivity and specificity of 6 cm segmental study were compared with those of 10 cm segmental study in these patients. RESULTS: The sensitivity and specificity came out to be 76% and 92% for the 6 cm segmental study and, 52% and 96% for the 10 cm segmental study. CONCLUSION: The sensitivity of 6 cm segmental NCS was much higher compared with 10 cm segmental NCS, whereas the specificity was similar in both tests. For screening of the UNE, 6 cm segmental NCS seems to be a more efficacious test.

Clinical Utility of Flexor Carpi Radialis H-Reflex in the 7th Cervical Radiculopathy

OBJECTIVE: To determine the clinical utility of flexor carpi radialis (FCR) H-reflex with and without facilitation in the diagnosis of 7th cervical radiculopathy. METHOD: Thirty-four subjects (27 men, 7 women) participated in this study showed symptoms and signs suggesitive of cervical radiculopathy and every subject had single herniated cervical disc on MRI study. All participants underwent electrophysiologic study including routine nerve conduction study (NCS), electromyography (EMG), FCR H-reflexes with and without facilitation in both arms. Abnormal parameters for FCR H-reflex were 1) side to side latency difference more than 1.0 msec, 2) absence of FCR H-reflex in one side, 3) side to side amplitude ratio below 33% for without facilitation and 22% for facilitation. If the subjects had at least one of the three abnormal parameters, we concluded as having abnormal FCR H-reflex. RESULTS: In the FCR H-reflex without facilitation group, we were not able to elicit FCR H-reflex in both arms in 17 subjects. Among the 17 subjects with elicited FCR H-reflex, 7 had abnormal FCR H-reflex (C7 root; 4, other roots; 3). In the FCR H-reflex with facilitation group, FCR H-reflex was obtained in 32 subjects, 13 out of the 32 showed abnormal FCR H-reflex (C7 root; 6, other roots; 7). The sensitivity and specificity of FCR H-reflex without facilitation in the diagnosis of 7th cervical radiculopathy were 67%, 73%, with facilitation it were 50%, 65%. CONCLUSION: Even though FCR H-reflex without facilitation is superior in its sensitivity and specificity, low elicitabiliy is the factor that limits its clinical utility. FCR H-reflex with facilitation with its good elicitability, seems to be a useful adjunctive method to routine NCS and EMG examination in the diagnosis of 7th cervical radiculopathy.