Evaluation of unilateral sensorineural hearing loss in the pediatric patient

Objectives: This study is a review of our series of pediatric patients with unilateral sensorineural hearing
loss (USNHL) to report abnormalities on imaging studies, review genetic and ophthalmologic results, and
survey audiometric findings.
Methods: This study is a retrospective chart review of all pediatric patients with USNHL seen between 1/
1/03 and 12/31/08 at our institution. The study was approved by the institutional review board.
Results: Eighty-nine cases were identified with audiometric findings confirming unilateral hearing
thresholds greater than 20 dBHL with no conductive component. There were 48 males and 41 females.
Average age of diagnosis was 7 years. One audiogram showed low-frequency loss, 17 mid-frequency, 29
high-frequency, and 32 flat. Ten patients were diagnosed by auditory brainstem response testing at
another institution, with thresholds not available for review. Eleven percent of patients progressed to
bilateral loss. Sixty-one patients underwent computed tomography of temporal bones (CTTB). Twenty of
61 scans identified 34 anomalies including 15 enlarged vestibular aqueducts (EVAs), 8 Mondini, and 3
superior semicircular canal dehiscences (SSCDs). Thirty-one of 89 patients underwent magnetic
resonance imaging (MRI). Three of these 31 patients had positive findings including 1 EVA, 1 Mondini,
and 1 asymmetric internal auditory canal. When CTTB was positive, no additional lesions were detected
on MRI. When CTTB was negative and MRI was done in 20 patients, 2 additional lesions were detected by
MRI. Fourteen patients had genetics evaluation of which 6 had positive findings, including CHARGE,
VACTERL, Goldenhar, and 3 were heterozygous for a Connexin mutation.
Conclusions: CTTB is an effective diagnostic tool for USNHL. MRI should be considered in patients with
negative CTTB. Genetics and ophthalmologic evaluations are recommended for patients with risk factors
or an abnormal clinical examination. Close follow-up is essential due to high rate of hearing loss
progression.