Sensorineural hearing loss

In cases of unilateral or asymmetrical sensorineural hearing loss, an acoustic schwannoma should be excluded. Gadolinium-enhanced MRI is recommended for this purpose. Apart from the internal auditory canal and cerebellopontine angle, attention should also be paid to the labyrinth, as a lesion may be detected at this level (see acoustic schwannoma, cochlea, inner ear). Sometimes other lesions are encountered in the internal auditory canal or cerebellopontine angle (see cerebellopontine angle tumours). A neurovascular conflict is an uncommon cause of unilateral sensorineural hearing loss (Fig.1).

The diagnostic yield of imaging is low when there is bilateral symmetric sensorineural hearing loss in an older patient (over 55 years). If imaging is performed in such a patient, MRI is preferred, unless Pagets disease is suspected, a disease better visualized using CT.

In children with symmetrical sensorineural hearing loss, CT or MRI may be used. If the MR study includes thin T2-weighted fast spin-echo or gradient echo images, both techniques allow a good evaluation of the labyrinth in a search for congenital anomalies (cochlea (VI:2), Fig. 1). The advantage of MRI is that the neural structures in the internal auditory canal and cerebellopontine angle can also be evaluated (see vestibulocochlear nerve congenital anomalies).

In adolescents and young adults with symmetrical sensorineural hearing loss, otosclerosis should be excluded; CT is the preferred modality for evaluation of this disease.

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