Lateralization, impedance, auditory brain stem response and synthetic sentence audiometry in brain stem disorders.

Applied individually, the conventional audiometric tests are unsatisfactory in the diagnosis of retrocochlear disorders. An accurate identification of a retrocochlear lesion, however, is not always possible using a single test, and only an appropriate test battery provides the basis for correct prediction of a retrocochlear lesion. Because of this observation, lateralization tests, impedance studies, auditory brain stem responses and speech audiometry with synthetic sentences have been applied to patients affected with retrocochlear disorders (acute nucleoreticular vestibular syndrome, multiple sclerosis and focal lesions). Analysis of the results has demonstrated the value of the tests employed, but the various tests were not strongly correlated and are therefore complementary.