[H reflex in the diagnosis of lumbosacral nerve root entrapment].

This article was to obtain the normal values of H reflex and verify its reliability. The normal values for the H reflex were obtained from 103 healthy subjects. Statistical analysis was performed using stepwise regression. If the practical time interval H-M in ms was higher 1.8ms than the estimate, this S1 root was considered as abnormality. According to this normal value, we obtained 89% accuracy in 28 S1 roots compression when compared with operative findings. For this group patients, the myelography achieved an accuracy of 86%, the accuracy of CT was 72%. The diagnostic index of this diagnostic method was 176. Our investigation suggests that H reflex latency testing is a valuable tool in helping to diagnosing S1 root entrapment.