auditory neuropathy spectrum disorder in adults

It was quite a relief to her to have her experiences validated.

ANSD was not diagnosed until she reached the age of 18 when an ABR revealed absent responses. Despite her complaints of difficulty hearing, her symptoms were repeatedly dismissed because of normal audiograms. 6 The etiology of the patient with ANSD is unknown. The individual with cortical deafness may report being “deaf.” The middle latency response is expected to be absent 5.Ī recently published case study contrasted two patients, one patient diagnosed with ANSD and the other with cortical deafness. The individual's responses may be inconsistent for pure-tone testing, yet otoacoustic emissions and auditory brainstem responses are normal. If you see a patient that has suffered a stroke, cortical deafness is one possible complication. Cortical deafness is much rarer than ANSD and occurs when there are bilateral lesions in the primary auditory cortex. The second type of disorder, cortical deafness, may be confused with nonorganic hearing loss. Summing the two polarities cancels these components, demonstrating the lack of a true neural response. Auditory brainstem response waveforms obtained to clicks presented with condensation and rarefaction polarities demonstrate the reversal of polarity that is characteristic of auditory neuropathy spectrum disorder. The auditory brainstem response, recorded with both rarefaction and condensation polarities, should show an extended cochlear microphonic in individuals with ANSD (Figure 1).įigure 1. Scores on hearing-in-noise tests that are considerably worse than would be predicted from the audiogram are an indicator of the need to perform follow-up testing that can assess deficits beyond the cochlea. 3, 4 Therefore, it is important to include tests of word or sentence recognition in noise in the clinical protocol, especially when the patient expresses this particular complaint. A key feature of ANSD is a disruption of neural synchrony, 1, 2 and previous studies have demonstrated the disruptions in neural synchrony are associated with hearing difficulties in noise. The chief complaint of individuals with ANSD and a normal audiogram would be difficulty hearing in noise. Because some individuals with ANSD have completely normal audiograms, this disorder can go undiagnosed well into childhood or adulthood. But, ANSD can occur in infants who have no risk factors, and it will not be detected by programs that use otoacoustic emissions (OAE) screening for healthy low-risk infants. One disorder, auditory neuropathy spectrum disorder (ANSD), should ordinarily be detected when auditory brainstem response (ABR) testing is used in infant screening. CI seems a justified hearing rehabilitation option for children with ANSD and limited benefits from conventional hearing aids.Īuditory neuropathy Cochlear implant Cochleovestibular nerve Cognitive disorders Dyssynchrony Hearing aids.Two types of auditory disorders can easily be missed when the audiologic evaluation is limited to assessments of the peripheral auditory system. The pre-CI CAP and MSLDS scores were 2.5 (range 0-5) and 2.5 (range 0-6), while the post-CI scores 5.8 (range 2-9) and 7.7 (range 3-10), respectively.Īlthough the outcome of CI in children with ANSD might vary, it is favourable in most of the cases. Nine children were implanted bilaterally, while 13 were bimodal. Performance was assessed with categories of auditory performance (CAP) and the Manchester spoken language development scale (MSLDS).įull data were available in 27 implanted children with ANSD with average age at implantation 35.4 months (range 19-68 months). The pre- and post-CI hearing outcomes in children with ANSD were retrospectively evaluated. To present the outcomes of cochlear implantation (CI) in children with auditory neuropathy spectrum disorders (ANSD).

Auditory neuropathy spectrum disorder in adults