Effects of transcutaneous electrical nerve stimulation and aspirin on late somatosensory evoked potentials in normal subjects

The effects on late somatosensory evoked potentials (SEPs) of transcutaneous nerve stimulation (TENS) and aspirin (600 mg), compared with placebo, were studied in 32 young, healthy male and female volunteers. SEPs were produced by electrical stimulation of the median nerve at moderate, non-painful, intensities. There was a reduction in the peak-to-peak amplitude of the late components N 1P 2 (N 1 latency: 100–160 msec; P 2 latency: 160–260 msec) of the SEP in all groups over time. TENS but not aspirin produced further significant changes compared with placebo, including a fall in N 1P 2 amplitude, an increase in N 1 latency, and a decrease in the total excursion of the SEP between 25 and 450 msec after stimulus onset.