Central nervous system findings by magnetic resonance in children with profound sensorineural hearing loss.

Introduction: High-resolution magnetic resonance studies are an important tool in the investigation of the etiology of childhood sensorineural hearing loss. An added benefit with magnetic resonance is the ability to screen the central nervous system for findings which may adversely affect the neurodevelopmental outcome of these children.

Objective: To determine the proportion of cases and significance of associated intracranial abnormalities as detected by central nervous system high-resolution magnetic resonance imaging in children with profound sensorineural hearing loss.

Methods: Retrospective chart review of children undergoing evaluation for cochlear implantation in a tertiary care academic children's hospital with high-resolution magnetic resonance of the temporal bone and brain during a 21 month period. Magnetic resonance studies were interpreted by an experienced senior neuroradiologist blinded to the identity and clinical data of the patients.

Results: Forty patients were identified. All had the same magnetic resonance study consisting of a 3D high-resolution sequence through the temporal bone as well as a T1 sagittal and T2 axial screening sequence of the brain. Eight patients (20%) showed significant brain abnormalities by magnetic resonance imaging ranging from myelination delays to migrational anomalies. Temporal bone abnormalities were not seen. Three patients with Connexin-26 mutations had no associated brain abnormalities by magnetic resonance.

Conclusions: A significant proportion of our patients being investigated by magnetic resonance imaging for profound sensorineural hearing loss show migrational abnormalities of the central nervous system, suggesting a central origin to their hearing loss. Some of these findings may result in neurodevelopmental delay and hence, negatively impact the success of cochlear implantation. We propose that magnetic resonance imaging of the temporal bone as part of the evaluation protocol for cochlear implantation in children should include central nervous system screening.