Elevated ABR thresholds in the presence of otoacoustic emissions: case series

The article presents three clinical cases of an unusual audiological profile in children, not previously described in the literature. The cases are of interest due to the atypical symptomatology featuring preserved otoacoustic emissions (OAEs) concurrent with elevated thresholds of auditory brainstem responses (ABRs). Notably, wave V exhibited normal morphology and latency; in some instances, the ABR thresholds correlated with the behavioral thresholds. This clinical presentation cannot be classified as either conventional peripheral sensorineural hearing loss or an auditory neuropathy spectrum disorder. It is hypothesized that the morphological substrate of this condition is a lesion at the level of the inner hair cell or the synapse. The underlying pathogenesis is suggested to involve mild impairments in neural synchronization, which are sufficient to allow for the recording of ABRs with thresholds that, in some cases, correlate with behavioral responses.