DISEASE PAGE

Acoustic Neuroma (Vestibular Schwannoma)

Preserved emissions with an abnormal ABR — the classic site-of-lesion picture.

The OAE signature

Emissions may be preserved despite a measurable unilateral sensorineural loss — the tumour is retrocochlear, so the outer hair cells it spares can still emit.[9]
Preserved emissions alongside an abnormal auditory brainstem response point to a lesion behind the cochlea and prompt imaging of the internal auditory canal.[6]

— Normal ear— Acoustic Neuroma (Vestibular Schwannoma)

Simulated TEOAE comparison. Educational signal model — not recorded patient data.

Audiogram companion

The pure-tone audiogram below accompanies the OAE signature. Reading the two together — what the threshold shows and what the emission shows — is the core diagnostic skill.

○ Right — PTA 40 dB (Moderate)✕ Left — PTA 17 dB (Normal)

Pure-tone audiogram companion. dB HL increases downward, following clinical convention. Illustrative thresholds — not recorded patient data.

Why the emission looks this way

A vestibular schwannoma arises on the vestibulocochlear nerve and compresses neural structures. The OAE tests only the pre-neural cochlea, so it can look normal while neural transmission — and the ABR — is disturbed.[2]

TEACHING POINT

Like auditory neuropathy, this is a preserved-OAE / abnormal-ABR dissociation — but the lesion is a unilateral mass, not a disorder of neural synchrony. An MRI of the internal auditory canal is the definitive next step.[6]

Sources for this page are listed on the References page. Browse all condition patterns from the atlas home.