Test-retest reliability of the somatosensory blink reflex and its inhibition.

Prepulse inhibition (PPI) involves inhibition of the blink reflex by a weak stimulus or prepulse presented immediately prior to the blink reflex-eliciting stimulus. Ten subjects were tested for PPI two times each day with a 60 min pause between tests, for 4 days spaced 1 week apart. Both the somatosensory blink reflex and its inhibition by an acoustic prepulse, presented 50, 100, 200, 400 and 800 ms prior to the reflex-eliciting stimulus, were investigated. The results showed very high reliability for the blink reflex across all eight tests (Chronbach's alpha=0.98). Inhibition of the reflex by a prepulse displayed alphas of >0.94, and percentage of PPI also displayed significant reliability. Blink latency also displayed high reliability. In sum, the reliability of the somatosensory blink reflex and its inhibition is very high.