Stapedial Reflexes in Neonates
Berlin, Hood, and colleagues (2005) reported that when otoacoustic emissions are present and acoustic reflexes are absent a “strong suspicion” of auditory neuropathy spectrum disorder (ANSD) should be raised. Further, given the earlier scenario, the authors recommended auditory brainstem response (ABR) testing test with positive and negative polarity clicks should be acquired.
Recently, Kei (2012) evaluated 68 full-term neonates who passed automated-ABR tests, transient-evoked otoacoustic emission (TEOAE) and high-frequency tympanometry tests at 1000 Hz, with regard to establishing normative acoustic stapedial reflex threshold (ASRT) measurements and test-retest reliability. The average age of the 68 subjects (at time of test) was 2.5 days. Kei defines ASRT as the “lowest stimulus intensity that produces a detectable change in acoustic admittance…” Kei reports the ASRT has not previously been widely used in 0 to 6 month olds. However, 30 times more babies are identified (via newborn hearing screening programs) with conductive hearing loss than sensorineural hearing loss. Therefore, high-frequency tympanometry and ASRT used in tandem with OAEs can offer important information with regard to the early diagnosis and management of children with ANSD.
In brief, for 500 Hz the mean ASRT was 82 dBHL, at 2000 Hz the mean ASRT was 71 dB, at 4000 Hz the mean ASRT was 65 dB and given a Broad Band Noise (BBN) stimulus, the mean ASRT was 57 dB. Of note, the normative data demonstrated a statistically significant frequency effect with no main effects for ear or gender. The authors report a moderate-to-high correlation (in general) with regard to test-retest for tones and the BBN conditions. Kei suggests “The ASR test can be included in a test battery for diagnosing hearing loss in the neonatal population.”
For More Information, References, and Recommendations
Berlin CI, Hood LJ, Morlet T, Wilensky D, St. John P, Montgomery E, Thibodaux M. (2005) 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. Journal of the American Academy of Audiology 16:546–553.
Kei J. (2012) Acoustic Stapedial Reflexes in Healthy Neonates- Normative Date and Test-Retest Reliability. Journal of the American Academy of Audiology 23(1):46–56.