Background: Click-evoked auditory brainstem responses (ABRs) are a valuable tool for probing
auditory system function and development. Although it has long been thought that the
human auditory brainstem is fully mature by age 2 yr, recent evidence indicates a
prolonged developmental trajectory.
Purpose: The purpose of this study was to determine the time course of ABR maturation in a
preschool population and fill a gap in the knowledge of development.
Research Design: Using a cross-sectional design, we investigated the effect of age on absolute latencies,
interwave latencies, and amplitudes (waves I, III, V) of the click-evoked ABR.
Study Sample: A total of 71 preschoolers (ages 3.12–4.99 yr) participated in the study. All had
normal peripheral auditory function and IQ.
Data Collection and Analysis: ABRs to a rarefaction click stimulus presented at 31/sec and 80 dB SPL (73 dB nHL)
were recorded monaurally using clinically-standard recording and filtering procedures
while the participant sat watching a movie. Absolute latencies, interwave latencies,
and amplitudes were then correlated to age.
Results: Developmental changes were restricted to absolute latencies. Wave V latency decreased
significantly with age, whereas wave I and III latencies remained stable, even in
this restricted age range.
Conclusions: The ABR does not remain static after age 2 yr, as seen by a systematic decrease in
wave V latency between ages 3 and 5 yr. This finding suggests that the human brainstem
has a continued developmental time course during the preschool years. Latency changes
in the age 3–5 yr range should be considered when using ABRs as a metric of hearing
health.
Key Words
Auditory brainstem response - child - preschool - development
