Emily Spitzer1, Travis White-Schwoch1, Kali Woodruff Carr1, Erika Skoe2, Nina Kraus3. 1. Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL. 2. Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL; Current address: Department of Speech, Language, and Hearing Sciences, Department of Psychology Affiliate, Cognitive Science Program Affiliate, University of Connecticut, Storrs, CT. 3. Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL; Department of Neurobiology and Physiology, Department of Otolaryngology, Institute for Neuroscience, Northwestern University, Evanston, IL.
Abstract
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. American Academy of Audiology.
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. American Academy of Audiology.