Brainstem auditory evoked-potentials in dairy cows recorded with Nape-Vertex derivation

摘要

Brainstem auditory-evoked potentials (BAEP) are bioelectric waves that can be registered in the 10 ms following an auditory stimulus. Each electric potential, identified with consecutive Roman numerals, is generated by the activation of one of the subcor-tical components of the acoustic pathway. The BAEP test is used in the clinical diagnosis of hearing impairment (Kay et al., 1984) and in brainstem pathologies (Fischer and Obermaier, 1994). The BAEP trace can be registered from different points of the cranial region, but the most frequently used derivations position the electrodes behind the stimulated ear (Ai) and on the cranial vertex (Vertex). The possibility of applying the BAEP test in early diagnosis of CNS pathology in the cow is currently being studied. However, the use of this method for epidemiological studies in the field, on a large number of animals, would require several modifications in order to reduce manoeuvres and testing time, without losing test reliability. The aim of this work was to verify the efficacy of the BAEP test using a single derivation, with electrodes positioned at the Nape-Vertex.