To investigate whether the aetiology for hearing impairment in neonates with unilateral auditory neuropathy spectrum disorder could be explained by structural abnormalities such as cochlear nerve aplasia, a cerebellopontine angle tumour or another identifiable lesion.

In this prospective case series, 17 neonates were diagnosed with unilateral auditory neuropathy spectrum disorder on electrophysiological testing. Diagnostic audiology testing, including auditory brainstem response testing, was supplemented with computed tomography and/or magnetic resonance imaging.

Ten of the neonates (59 per cent) showed evidence for cochlear nerve aplasia. Of the remaining seven, four were shown to have another abnormality of the temporal bone on imaging. Only three neonates (18 per cent) were not diagnosed with cochlear nerve aplasia or another lesion. Three computed tomography scans were reported as normal, but subsequent magnetic resonance imaging revealed cochlear nerve aplasia.

Auditory neuropathy spectrum disorder as a unilateral condition mandates further investigation for a definitive diagnosis. This series demonstrates that most neonates with unilateral auditory neuropathy spectrum disorder had pathology as visualised on computed tomography and/or magnetic resonance imaging scans. Magnetic resonance imaging is an appropriate first-line imaging modality.

Description of a female patient with diagnosed Kjer's disease and sensorineural hearing loss, who specifically complained of a progressive inability to understand speech in noisy situations.

Case report.

A 30-year-old, Caucasian woman with Kjer's disease.

Audiological assessment showed low-frequency sensorineural hearing loss and a disproportionate deterioration in speech discrimination. This inconsistency gave rise to suspicion of possible aggravation. Follow-up testing showed that brainstem responses were absent, while clear otoacoustic emissions and cochlear microphonics were present. Hearing aids were fitted but no improvement was shown.

This case shows a combination of auditory neuropathy and Kjer's optic neuropathy. It also illustrates that the combination of unexplained hearing loss and apparently inconsistent audiometric outcomes may be associated with auditory neuropathy. Such unexpected hearing evaluation outcomes may be due to other neurological conditions, such as Kjer's disease.