Hyperacusis in Williams syndrome

Objective: To define hyperacusis in audiologic parameters and to further el ucidate central and peripheral auditory pathways. Design and Setting: Theories surrounding hyperacusis have always been highl y debated. A group of children with Williams syndrome universally complain of hyperacusis. They have highly reproducible behavioural responses to nois e and are thus hampered in their social interactions. Loss of inhibitory mo dulation to efferent sensory input to the cochlea is thought to be a possib le mechanism. Methods: Nine patients with Williams syndrome received a complete audiologi c work-up, including audiogram, speech reception thresholds, acoustic refle xes, impedance, and transient evoked otoacoustic emissions (TEOAEs). Main Outcome Measures: Assessment of the efferent system is done by measuri ng changes in TEOAEs following stimulation of the contralateral ear. Results: Three patients had high-frequency sensorineural hearing loss (SNHL ) and thus, as expected, absent TEOAEs, indicating cochlear damage. Two had normal hearing and normal TEOAEs. However, four patients had normal hearin g with absent TEOAEs. Conclusions: These findings are suggestive of cochlear disease and may, in fact, support the hypothesis of outer hair cell modulation by the ipsilater al medial olivocochlear system. Behavioural aspects of the syndrome make au diologic testing difficult. Thus, the diagnosis of SNHL may be hampered if it truly exists. The data show a preponderance of SNHL in the older age gro ups of our study population. This either reflects previously missed diagnos es or underlying cochlear disease, which may manifest later in life. Thus, this finding blurs the boundary between loudness recruitment and hyperacusi s.