Our case series involves a subpopulation of hearing-impaired children with significant discrepancies between the results of their ABR and ASSR tests.
21,22) ASSR thresholds can be used to predict the configuration of pure-tone audiometry, (23,24) which would contribute to an appropriate bilateral hearing aid fitting in hard-of-hearing infants.
To achieve this, especially in children with difficult or unreliable behavioral audiometry, ASSR threshold-based bilateral hearing aid fitting is necessary to provide frequency-specific amplification of hearing and appropriate propulsion in the prelinguistic vocalizations of monitored infants.
The ASSR revisited: A clinical comparison of two stimuli.
General and audiologic characteristics of children presenting with significant discrepancies between ABR and ASSR test results kHz ABRs, ASSRs, right dBHL Pt.
The patient was seen for follow-up impedance audiometry and ASSR measurements 6 months later.
ASSR testing in the right ear found no predicted behavioral responses at equipment limits.
At follow-up 10 months later, ASSR audiometry yielded type A tympanograms bilaterally (figure 2,B).
Prior to the availability of ASSR audiometry, the setting of target gains in the "no response by ABR" child was problematic at best, and gain targets were only educated guesses.
The 2 cases described here illustrate the importance that middle ear function has on ASSR testing:
Previous ASSR testing had yielded a measurable response only at 8,000 Hz.
It is not surprising that middle ear dysfunction appears to affect the ASSR threshold response.