title: Pressurized Wideband Acoustic Stapedial Reflex Thresholds: Normal Development and Relationships to Auditory Function in Infants.
abstract: This study analyzed effects of pressurization on wideband acoustic stapedial-muscle reflex (ASR) tests in infants cared for in normal newborn (NN) and neonatal intensive care units (NICU). Effects of hearing-screening outcomes on ASR threshold measurements were also evaluated, and a subsequent longitudinal study established normative threshold ranges over the first year after birth. An initial experiment compared thresholds in newborns measured at ambient pressure in the ear canal and at the tympanometric peak pressure. ASR thresholds for broadband noise were higher for ears that did not pass newborn hearing screening and ASR threshold was 14 dB higher for real-ear compared to coupler conditions. Effects of pressurization were significant for ears that passed screening; thus, ASR testing in infants should be conducted at tympanometric peak pressure. ASR threshold was significantly higher for ears that referred on transient evoked otoacoustic emissions and Auditory Brainstem Response (ABR) screening tests and also for ears with conductive and sensorineural hearing loss diagnosed by ABR. Developmental ASR changes were significant over the first year for both normal and NICU infants. Wideband pressurized ASR thresholds are a clinically relevant measure of newborn hearing screening and diagnostic outcomes.
authors.affiliation: Division of Audiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45213, USA. lisa.hunter@cchmc.org.
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Hunter
authors.affiliation: Boys Town National Research Hospital, 555 N. 30th St., Omaha, NE, 68131, USA.
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Keefe
authors.affiliation: National Center for Rehabilitative Auditory Research, Portland VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, OR, 97239, USA.|Department of Otolaryngology Head and Neck Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA.
authors.forename: M Patrick
authors.initials: MP
authors.lastname: Feeney
authors.affiliation: Boys Town National Research Hospital, 555 N. 30th St., Omaha, NE, 68131, USA.
authors.forename: Denis F
authors.initials: DF
authors.lastname: Fitzpatrick
mesh_terms: D000158:Acoustic Impedance Tests; D001309:Auditory Threshold; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D006309:Hearing; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D012022:Reflex, Acoustic / Q000502:physiology*
keywords: acoustic stapedial reflex; development; middle ear; middle ear muscle reflexes