Prevalence of auditory neuropathy/synaptopathy in a population of children with profound hearing loss.
OBJECTIVE
To examine the prevalence of auditory neuropathy/synaptopathy (AN/AS) in a cohort of children with profound hearing loss.


METHODS
From 1997 until 2004, 5190 children, aged 1-15 years, whose hearing ability was uncertain or who had risk factors for hearing impairment were investigated with subjective and objective hearing tests. Three thousand four hundred and fifteen from these children were screened for AN/AS using pure-tone audiometry, impedance measurement, transient evoked otoacoustic emissions (TEOAE) and click-evoked auditory brainstem responses (ABR).


RESULTS
From 3415 patients who participated in an ABR and TEOAE assessment, 379 children showed absent or elevated (> or = 80 dB nHL) ABR thresholds. Within this group we found 32 cases with evidence of AN/AS via visible TEOAE and/or cochlear microphonics (CM) coupled with absent ABR. In the remaining 3036 children, AN/AS, could be ruled out by means of detectable ABR-thresholds and coherent findings in pure-tone audiometry and TEOAE assessment. This results in a prevalence of AN/AS of 0.94% within the group at risk for hearing loss, compared to 8.44% among profoundly hearing impaired children.


CONCLUSIONS
This study shows that AN/AS is a common finding in the population of hearing impaired infants. In the majority of our AN/AS children (50%, n=16), an early audiological diagnosis was made under the age of 12 months. Therefore, clinicians and other health care professionals should generally be sensitised for AN/AS in infants, so that an appropriate treatment can promptly be initiated. Further research on clinical and pathophysiological aspects is necessary to better identify and manage patients suffering from AN/AS.
Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Kerpener Strasse 62, 50924 Cologne, Germany. astrid.foerst@uni-koeln.de
Astrid
A
Foerst
Dirk
D
Beutner
Ruth
R
Lang-Roth
Karl-Bernd
KB
Huttenbrink
Hasso
H
von Wedel
Martin
M
Walger
D000158:Acoustic Impedance Tests; D000293:Adolescent; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012189:Retrospective Studies; D012307:Risk Factors; D009435:Synaptic Transmission / Q000502:physiology