Dermatomal Somatosensory Evoked Potentials in Lumbosacral Radiculopathy

ABSTRACT

This study was conducted to get normal data of derrnatomal somatosensory evoked potentials (DSEP) from the lumbosacral dermatome and to evaluate the efficacy of DSEP in the diagnosis of lumbosacral radiculopathy. We examined scalp-recorded DSEP from stimulation of L4. L5 and Sl derrnatomes. DSEP was tested on 26 healthy adult volunteers (11 men and 15 women), age ranging from 22 to 66 years and 12 patients (7 men and 5 women) with lumbosacral radiculopathies. Norrnal values of P latenc! Of DSEP from stimulation of L4. L5 and S1 derrnatomes were 41.3+24.9 msec. 46.4+3.30 msec and 46.8+3.04 msec and the interside differences of the P, latency uere 1.57+1.06 msec, 1.06+0.93 msec and 1.38+0.89 msec, respectively. The latencies of DSEP were significantly influenced by age and height. But the amplitudes were not. In the seven of the twelve patients with lumbosacral radiculopathies the DSEP findings concurred with clinical, CT and/or MRI findings. In 5 cases DSEP gave different information, indicating no abnormality in three patients, more extended radiculopathy in one, and more reduced radiculopathy in one, compared with clinical and radiological findings. Above observations suggest that DSEP test is a simple. Noninvasive. Economic and useful alternative test for the diagnosis of lumboscral radiculopathy.