Extensor digitorum brevis reflex in normals and patients with radiculopathies

This prospective study evaluated the extensor digitorum brevis deep tendon reflex (EDBR) in a normal population and in patients with L‐5 and S‐1 radiculopathies. There were 88 subjects: 53 normals, 17 L‐5, and 18 S‐1 radiculopathy subjects. The clinical EDBR revealed a 91% specificity, with 18% sensitivity for L‐5, and 11% for S‐1. The electrodiagnostic EDBR yielded increased sensitivities of 35% for L‐5 ( P = 0.07) and 39% for S‐1 ( P = 0.04), with 87% specificity. H‐reflexes showed 50% sensitivity for the S‐1 group ( P = 0.0006) and 91% specificity. EDBR latencies were significantly related to age and leg length ( r 2 = 0.46, P < 0.0001). Age alone explained 26% ( P < 0.0001) of the EDBR variability and leg length 20% ( P < 0.0001). EDBR clinical and electrodiagnostic reflexes have low sensitivities, high specificities, and do not discriminate L‐5 from S‐1 root involvement.© 1995 John Wiley &Sons, Inc.