Cortical Evoked Responses in Neuro-Otologic Diagnosis

The averaged vertex response has definite but limited diagnostic uses in clinical otology. The vertex response can be used with a reasonable degree of accuracy (1) to determine objectively the thresholds of hearing in subjects who cannot be tested satisfactorily by conventional audiometric methods; (2) to differentiate conductive from sensorineural hearing loss; and (3) to differentiate organic from functional hearing impairment. Preliminary evidence suggests that the vertex response can be used to distinguish between auditory and pseudoauditory air-bone gap in patients who have been severely hard of hearing since early childhood. At the present time the vertex response has not been found to be of significant value in differentiating cochlear and retrocochlear lesions.