Prevalence of Auditory Neuropathy: Prospective Study in a Tertiary-Care Center

Auditory neuropathy in a low-risk population: a review of the literature

OBJECTIVE

Collect all available published evidence on the prevalence of auditory neuropathy in the well baby population and calculate the contribution of this to the false negative rate of oto-acoustic emission based newborn hearing screening programs.

METHOD

PubMed and EMBASE were searched for relevant articles published between 1996 and 2010. Medical Subject Headings terms included 'Auditory disease', 'Prevalence' and 'Child' and their relevant synonyms. Included were original studies, which focused on well babies and reported the prevalence of auditory neuropathy.

RESULTS

Of 519 citations 4 articles met the inclusion criteria. The population based prevalence of auditory neuropathy in children in population hearing screening was found to vary between 0.006% (SD 0.006) and 0.03% (SD 0.02). The false negative rate, caused by missed children with auditory neuropathy, is between 4 and 17%.

CONCLUSION

The available information on the prevalence of auditory neuropathy in the well baby population is poor. However, if oto-acoustic emission screening is used in the first stage of a neonatal hearing screening program, children with auditory neuropathy are missed. The cost-effectiveness of population-based screening using auditory brainstem response should be studied.

Prevalence and risk factors for auditory neuropathy spectrum disorder in a screened newborn population at risk for hearing loss

OBJECTIVE

To determine the prevalence of Auditory Neuropathy Spectrum Disorder (ANSD) among infants with sensorineural hearing loss (SNHL) and discuss the risk factors.

METHODS

The study group was comprised of children diagnosed with ANSD. Criteria for inclusion in the study group were as follows: permanent sensorineural hearing loss (SNHL); normal transient evoked or distortion product OAEs; absent or elevated middle-ear muscle reflexes (MEMR); severely abnormal or absent ABR waveform. All newborns were screened via a two-stage protocol, involving OAEs and ABR for the repeatedly referred cases and all neonates with one or more risk factors.

RESULTS

From 2002 to 2011, 9419 infants whose hearing ability was uncertain or who had risk factors for hearing loss were investigated. From this population, 352 were diagnosed with SNHL. Of these 352 children, 18 (5.1%) were diagnosed with ANSD. In the ANSD group, prematurity and low birth weight (<1500 g) were observed in 5 cases; ototoxical medication in 8 cases; mechanical ventilation in excess of 5 days in 5 cases. Hyperbilirubinemia was observed in 7 cases, but severe hyperbilirubinemia requiring an exchange transfusion was not observed; 4 patients had no risk factors, 6 patients had only one risk factor, and the 8 remaining had two or more risk factors.

CONCLUSION

Auditory Neuropathy Spectrum Disorder is not an extremely rare hearing disorder. Screening for hearing loss via OAEs, MEMR and ABR examinations concurrently are essential for the accurate diagnosis of ANSD.

Prevalence of auditory neuropathy (AN) among infants and young children with severe to profound hearing loss

Auditory neuropathy is a challenging disorder and needs special habilitative/rehabilitative approach. This study aimed to detect its prevalence among infants and young children with severe to profound hearing loss. 112 infants and young children with age ranged 6-32 months were examined and diagnosed as having severe to profound hearing loss and were referred for hearing aid fitting. Those infants were reassessed in our centers for detecting cases with auditory neuropathy. The study group was subjected to immittancemetry, behavioral observation audiometry, ABR and cochlear microphonics.

RESULTS

15 patients were found to have auditory neuropathy according to our criteria for diagnosis.

CONCLUSIONS

The prevalence of AN in the study group was 13.4%. CM were recommended to be tested routinely during ABR assessment whenever abnormal results are obtained.