Temporal bone abnormalities associated with hearing loss in Waardenburg syndrome.

OBJECTIVES/HYPOTHESIS: The objectives were to correlate audiometric thresholds with radiological findings and to determine the prevalence of inner ear radiological abnormalities in patients with hearing loss and Waardenburg syndrome.

STUDY DESIGN: The study was a retrospective review of patients with Waardenburg syndrome identified in a pediatric hearing-impaired population and human genetics clinic.

METHODS: Nine children with Waardenburg syndrome were identified. Eighty-nine children without sensorineural hearing loss served as control subjects. Clinical data, audiometric thresholds, and radiographic temporal bone measurements in these children were analyzed.

RESULTS: Seven children were identified with hearing loss and Waardenburg syndrome. Four children had Waardenburg syndrome type 1, and three children had Waardenburg syndrome type 2. The overall prevalence of hearing loss in the total study population with Waardenburg syndrome was 78%. The mean pure-tone average was 99 dB. All of the children had sensorineural hearing loss. The hearing outcome was stable in 86% of the children. Twelve temporal bones were available for radiological analysis by computed tomography. Enlargement of the vestibular aqueduct was found in 50% of the CT scans. There was a significant difference in measurements of vestibular aqueduct width at the midpoint between the patients with Waardenburg syndrome and the control group (P <.05). There were also significant differences in the measurements of the vestibule (P =.0484), internal auditory canal (P =.0092), and modiolus (P =.0045) between the children with Waardenburg syndrome and the control group.

CONCLUSION: A profound sensorineural hearing loss was characteristic of the study population with Waardenburg syndrome. Overall, 100% of patients with hearing loss and Waardenburg syndrome had temporal bone anomalies on at least one measurement of their inner ear, and 50% had an enlargement of the vestibular aqueduct at the midpoint. As shown by computed tomography, enlargement of the vestibular aqueduct and the upper vestibule, narrowing of the internal auditory canal porus, and hypoplasia of the modiolus are features of Waardenburg syndrome.