What investigations are indicated for a patient with unilateral hearing loss?

For a patient presenting with unilateral hearing loss, an audiological assessment should be arranged, including pure tone audiometry to differentiate conductive from sensorineural hearing loss and to characterize the severity and pattern of hearing loss at various frequencies ¹.

Consider referral for additional diagnostic assessment if there are specific symptoms such as sudden or rapid onset of hearing loss, or if the hearing loss is unexplained by external or middle ear causes ¹.

Offer MRI of the internal auditory meati to adults with hearing loss and localising symptoms or signs (such as facial nerve weakness) that might indicate a vestibular schwannoma or CPA lesion, irrespective of pure tone thresholds ¹.

Consider MRI of the internal auditory meati for adults with sensorineural hearing loss and no localising signs if there is an asymmetry on pure tone audiometry of 15 dB or more at any 2 adjacent test frequencies, using test frequencies of 0.5, 1, 2, 4 and 8 kHz ¹.