T. K. Parthasarathy
Dept. of Speech Pathol. and Audiol., Southern Illinois Univ., Edwardsville, IL 62026
Cardinal Glennon Children's Hospital, St. Louis, MO 63104-1095
St. Mary's Health Ctr., St. Louis, MO 63117
Effects of repetition rate, phase, and frequency on wave V latency of the auditory brain-stem response (ABR) were evaluated and compared in ten normal newborn neonates and adult subjects. Single cycle sinusoids at 0.25 and 2.0 kHz were presented monaurally via an insert earphone at 75 dB nHL, using either a condensation (C) or a rarefaction (R) stimuli at two rates, 11.1 and 55.5/s. The stimulus phase by frequency interaction was significant. In both neonates and adult subjects, the ABR wave V latency for R stimuli was significantly shorter compared to C stimuli at 0.25 kHz. However, the effect of phase on wave V latency was insignificant at 2.0 kHz. Furthermore, the stimulus rate by age interaction was significant. The ABR wave V latency shift with an increase in repetition rate was significantly greater in the newborn neonates than in the adult subjects.