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

TLDR

The study urges clinicians to include ipsilateral middle ear muscle reflex testing at 1 kHz and 2 kHz in perinatal hearing screenings that rely solely on otoacoustic emissions. Researchers selected 136 auditory neuropathy/dys‑synchrony patients from a 257‑subject database for whom middle ear muscle reflexes had been measured. All 136 patients exhibited either absent or elevated reflexes—none had normal reflexes at any frequency, and only three showed reflexes at ≤95 dB HL but never simultaneously at 1 kHz and 2 kHz in both ears—making the reflex findings incongruous with their normal otoacoustic emissions and suggesting that an ABR may be necessary.

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.