title: Aural Acoustic Stapedius-Muscle Reflex Threshold Procedures to Test Human Infants and Adults.
abstract: Power-based procedures are described to measure acoustic stapedius-muscle reflex threshold and supra-threshold responses in human adult and infant ears at frequencies from 0.2 to 8 kHz. The stimulus set included five clicks in which four pulsed activators were placed between each pair of clicks, with each stimulus set separated from the next by 0.79 s to allow for reflex decay. Each click response was used to detect the presence of reflex effects across frequency that were elicited by a pulsed broadband-noise or tonal activator in the ipsilateral or contralateral test ear. Acoustic reflex shifts were quantified in terms of the difference in absorbed sound power between the initial baseline click and the later four clicks in each set. Acoustic reflex shifts were measured over a 40-dB range of pulsed activators, and the acoustic reflex threshold was objectively calculated using a maximum 10 likelihood procedure. To illustrate the principles underlying these new reflex tests, reflex shifts in absorbed sound power and absorbance are presented for data acquired in an adult ear with normal hearing and in two infant ears in the initial and follow-up newborn hearing screening exams, one with normal hearing and the other with a conductive hearing loss. The use of absorbed sound power was helpful in classifying an acoustic reflex shift as present or absent. The resulting reflex tests are in use in a large study of wideband clinical diagnosis and monitoring of middle-ear and cochlear function in infant and adult ears.
authors.affiliation: Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE, 68131, USA. Douglas.Keefe@boystown.org.
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Keefe
authors.affiliation: National Center for Rehabilitative Auditory Research, VA Portland Health Care System, 3710 SW US Veterans Hospital Road, Mail Stop NCRAR, Portland, OR, 97239, USA.|Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., NRC04, Portland, OR, 97239, USA.
authors.forename: M Patrick
authors.initials: MP
authors.lastname: Feeney
authors.affiliation: Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Hunter
authors.affiliation: Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE, 68131, USA.
authors.forename: Denis F
authors.initials: DF
authors.lastname: Fitzpatrick
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001309:Auditory Threshold; D006309:Hearing; D006314:Hearing Loss, Conductive / Q000503:physiopathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012022:Reflex, Acoustic / Q000502:physiology*
keywords: absorbed sound power; acoustic stapedius reflex threshold; newborn hearing; wideband