Test-retest reliability of prepulse inhibition paradigm using auditory evoked potentials

Abstract

Prepulse inhibition (PPI) is a neurological phenomenon in which a weak initial stimulus reduces the level of responses to a subsequent stronger stimulus. Although acoustic startle reflexes are usually used for PPI examinations, recent studies have observed similar phenomena with event-related cortical potentials. In the present study, test-retest reliability of PPI measured using auditory change-related cortical responses was assessed in 35 healthy adults. Four sound stimuli were randomly presented at an even probability; Standard, Test alone, Prepulse alone, and Test + Prepulse. The Standard stimulus was a train of 25-ms tone pulses at 70 dB for 650 ms, while for Test alone and Prepulse alone, the sound pressure was increased to 80 dB at 350 ms and 73 dB at 300 ms, respectively. Measurements were performed twice with at least 7 days separation, and validity was evaluated using intra-class correlation (ICC) for latency, amplitude, and suppression rate of the P50, N100, and P200 components. The results showed high ICC values for the latency and amplitude of nearly all components, except for response to Prepulse alone (0.3–0.6). Furthermore, ICC for suppression rate was greater than 0.5 for the peak-to-peak amplitude. Good reproducibility for N100 and P200 components was obtained with this method. The present results support the PPI paradigm as a reliable tool for clinical measurements of inhibitory functions.