The effect of paired stimuli on blink reflex latencies in normal subjects

Abstract

In this study we assessed the effect of paired stimuli on the latencies and amplitudes of the blink reflex. Blink reflexes were performed with single and paired (5-ms interstimulus interval) stimuli in 47 patients. The changes in latencies between paired and single stimuli were calculated. Paired stimulation produced two types of R1 waveform morphologies: single- and double-peaked waveforms. Increases in R1 and contralateral R2 latencies with paired stimulation were significantly higher in those with single-peaked R1 responses compared to those with double-peaked R1 responses. Interpreting the blink reflex latencies using paired stimulation requires visualization of the R1 waveform morphology. A double-peaked R1 response requires no change in normal latency values, but the latency of a single-peaked R1 should be interpreted from the second shock artifact. The effect on the R2 latency is variable.