title: Absent or elevated middle ear muscle reflexes in the presence of normal otoacoustic emissions: a universal finding in 136 cases of auditory neuropathy/dys-synchrony.
abstract: We extracted a subpopulation of 136 patients (from our database of 257 AN/AD subjects) in whom middle ear muscle reflexes had been measured. None showed normal reflexes at all frequencies tested. Only three subjects showed any reflexes at 95 dB HL or below, but never at both 1 and 2 kHz in both ears whether ipsilaterally or contralaterally elicited. All the other reflex measures in these remaining 133 patients were either absent or observed above 100 dB HL, which is incongruous with their normal otoacoustic emissions throughout the frequency bands. Therefore, we urge colleagues to test ipsilateral middle ear muscle reflex at least at 1 kHz and 2 kHz in any perinatal hearing screening that depends solely on otoacoustic emissions. If the emissions are present and the reflexes are absent or elevated, an ABR may be required to properly intervene, because the management of AN/AD patients often differs drastically from what the behavioral audiogram or the ABR suggest.
authors.affiliation: Kresge Hearing Research Laboratory, Louisiana State University Health Sciences Center, New Orleans 70112, USA. cberli@lsuhsc.edu
authors.forename: Charles I
authors.initials: CI
authors.lastname: Berlin
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Hood
authors.forename: Thierry
authors.initials: T
authors.lastname: Morlet
authors.forename: Diane
authors.initials: D
authors.lastname: Wilensky
authors.forename: Patti
authors.initials: P
authors.lastname: St John
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Montgomery
authors.forename: Melanie
authors.initials: M
authors.lastname: Thibodaux
mesh_terms: D000158:Acoustic Impedance Tests; D000293:Adolescent; D000328:Adult; D000368:Aged; D001302:Audiometry, Speech; D001309:Auditory Threshold; D002648:Child; D002675:Child, Preschool; D003056:Cochlear Nerve / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012022:Reflex, Acoustic / Q000502:physiology*; D012189:Retrospective Studies; D000160:Vestibulocochlear Nerve Diseases / Q000503:physiopathology*