Unilateral Sensorineural Hearing Loss in Children: Natural History and Clinical Characteristics

Characterize hearing outcomes and etiologies of congenital and postnatal unilateral sensorineural hearing loss (SNHL).

Reviewed charts of children with unilateral SNHL, 2003-2019. Primary outcomes were changes in pure tone average (PTA) of affected and contralateral ears. Patients who failed a newborn hearing screen (NBHS) were considered 'congenital' onset, those who passed "postnatal," and those without "unknown." Demographics, infectious/genetic workup, audiograms, imaging, and hearing aid use were collected.

A total of 1264 charts reviewed, 476 subjects included: 156 congenital, 252 postnatal, and 68 unknown onset. The mean (SD) of the first PTA was 53.8(29.4) dB for affected and 10.6(5.8) dB for unaffected ears. Thirty-nine percent followed up > 5 years. Change in PTA over time was 3.0(14.5) dB for affected and -1.7(7.4) dB for unaffected ears. The congenital subgroup had poorer hearing in the affected ear at the first audiogram (p < 0.0001) and was more likely to have progressive hearing loss (p = 0.0040) than the postnatal subgroup. Imaging in 296 patients revealed ipsilateral abnormalities in 26.6% of CTs and 39.6% of MRIs. Absent/hypoplastic cochlear nerve was the most common abnormal and was associated with poorer hearing than those with normal nerves (p < 0.0001). Enlarged vestibular aqueduct was not associated with progression of hearing loss.

Hearing in both the affected and contralateral ears remained stable after the first audiogram in > 80% of patients. Patients with congenital loss had poorer hearing at diagnosis and were more likely to have progression than those with postnatal loss. MRI was more sensitive than CT in detecting an anatomic cause of SNHL, and absent/hypoplastic cochlear nerve was the most common finding.