NECK RETRACTION INCREASED CERVICAL H-REFLEX AND DECREASED NECK PAIN.

Abstract

1392 Neck exercises are the central treatment protocol for patients with neck pain. Extension, flexion or retraction movements have been prescribed based on patients self report of pain. The purpose of this study was to evaluate the use of the flexor carpi radialis (FCR) H-reflex in determining cervical root compression and decompression during neck retraction and correlate the finding with neck pain. Twelve subjects (20-40y) with confirmed symptoms of neck pain for more than 6 months volunteered for the study. The FCR H-reflex was elicited by electrical stimulation of the median nerve at the cubital fossa(0.5 ms., 0.2 pps at H-max) using bipolar surface electrodes. Signal was recorded from the FCR muscle using 500-2000 gain and 10-10,000 Hz bandpass. Pain intensity of the neck (evaluated by visual analog scale) and the H-reflex were recorded before and after A-upright sitting, B- 20min of reading and C- 20 repetitions of neck retractions. The peak to peak amplitude and the deflection latency were measured and averaged for 4 reflex representations. One way ANOVA and Spearman correlation were used for statistics. Results showed significant decrease in the H-reflex amplitude after reading and significant increase after neck retractions (p<0.001). No measurable changes were recorded in the H-reflex latency (p<0.34). Neck pain intensity was significantly increased after reading and decreased after neck retraction(p<0.001). Changes in the H-reflex amplitude and pain intensity during different testing conditions were strongly correlated (r=0.85- -0.82). These results imply a cervical root decompression during neck retractions and suggest it for effective therapy. They also confirm the objective utility of the FCR H-reflex for on line evaluation of patients with neck pain.