'Short-Latency' Somatosensory Evoked Potentials during Experimentally Induced Biodynamic Stress in Humans.

摘要

Averaged evoked potentials (EPS) were employed to monitor the structural and functional integrity of human somatosensory pathways before and after experimentally controlled exposures to impact acceleration. Somatosensory EPS were obtained from five research volunteers using recording electrodes placed on the scalp and neck and over ERB's point. The median nerve of the left arm was stimulated percutaneously at the wrist with 5/s, .2ms, rectanular pulses. Current levels (range 2.5 to 7.0 mA) were equal to the sum of sensation plus thumb movement thresholds. The magnitude of the thumb movement was monitored throughout an experiment. Telemetered electrophysiological data were stored on magnetic tape and analyzed off-line. In the analysis of these data, particular attention was paid to relative conduction times along the pathway from brachial plexus to hand-somatosensory cortex. The amplitude of the earlier cortical components N2 and P2 (with peak latencies 19 and 22 ms, respectively) and the absolute latencies of all EP peaks were also measured and analyzed. The results from impact acceleration events up to m/sq.second (sled accelerated from zero to 39 miles per hour in 5 feet 2 inches) revealed no clinically significant alterations of short-latency somatosensory EPS.