[Criteria for the differential diagnosis of cochlear-retrocochlear disorders with brain stem audiometry (author's...

Brain stem audiometry turned out to be a useful tool in the differential diagnosis of cochlear-retrocochlear damage. Reviewing the literature of recent years it becomes clear that various criteria are used to distinguish such lesions when interpreting the brain stem potentials. The most frequently used parameters are: 1. ipsilateral latency of potential V as compared to mean of normal population; 2. difference of latency of potential V of ipsi- and contralateral side; 3. ipsilateral latency difference potentials I -- V as compared to mean of normal population; 4. difference of latency difference potentials I -- V of ipsi- and contralateral side. Evaluating the registrations of brain stem potentials of 50 patients with uni- or bilateral cochlear lesions these parameters had a different degree of liability. Comparing latency differences of potentials I -- V of ipsi- and contralateral sides was the safest method to avoid a false positive diagnosis. It is discussed why this parameter should be the most suitable in the distinction of cochlear and retrocochlear lesions.