[Use of cross-correlation functions in the assessment of acoustically evoked brain stem potentials in patients with vertebrobasilar insufficiency and multiple sclerosis].

Brainstem acoustic evoked potentials (BAEP) in patients with vertebral-basilar insufficiency and multiple sclerosis are analysed by means of cross correlation functions. By comparing BAEP recordings of the right and left side this method yields a quantitative and objective valuation of the symmetry of the electrical brainstem activity whereby the BAEP waveform is also considered. The diagnostic value of the cross correlation function is studied by demonstration of examples and comparison of the patient groups with normal subjects. The presented method of analysis is not an alternative to the usual interpretation of latencies and amplitudes. But it may be recommended as a supplementary criterion, because without any additional effort it provides further objective information which can be useful for the valuation of BAEP in some cases, especially if the potentials are not well discernible.