Audiological findings in Williams syndrome : a study of 69 patients

The aim of this study was to investigate, in a clinical setting, the auditory function of a group of individuals affected by Williams syndrome (WS). Sixty-nine patients with WS, aged 2-30, underwent comprehensive audiological testing including air/bone conduction behavioral audiometry, speech audiometry, tympanometry and measurement of the acoustic reflex, transient evoked otoacoustic emissions and brainstem auditory evoked responses. Hearing loss, defined by a pure-tone average above 15 dB HL, affected 22.6% of the patients studied with traditional audiometry and was mostly slight in severity. Hearing loss was conductive in 9.4% of patients, mainly children with otitis media with effusion, and sensorineural in 13.2% of patients. However, 30% of the ears studied had a hearing impairment in the high frequency range (high-frequency pure-tone audiometry above 15 dB HL), higher in participants above 15 years (46.15%) than in the younger ones (23.45%). Contralateral stapedial reflexes were present in all patients with A-type tympanograms. Transient otoacoustic emissions were absent in 44% of the ears of patients with normal hearing. Brainstem auditory evoked responses fell within normal ranges thus confirming the absence of retrocochlear dysfunction. Although hearing loss does not seem to be frequent, a cochlear fragility, especially in the high frequency range, related to outer hair cells is characteristic of WS. Therefore we strongly recommend monitoring patients affected by WS using annual audiometric tests and performing otoacoustic emissions in order to identify a subclinical cochlear dysfunction which might benefit from an audiological follow up before the possible onset of hearing loss.