D.C.-Potentials in the Auditory Evoked Response in Man

Abstract

While the conventional auditory evoked response is mainly related to the onset of auditory stimuli and/or to their cessation (off-effect) during prolonged sinusoidal stimulation, a marked d.c.-potential could be recorded by means of a special d.c.-recording set-up in both animals and in man. Here, special precautions had to be taken to avoid polarization—artefacts originated by the electrodes (Beckman-type). Those difficulties have been overcome and clearly reproducible records of d.c.-potentials in man could be obtained in our Institute. These d.c.-potentials depend upon both stimulus intensity and stimulus duration. They show in addition interaction with other sensory modalities such as visual ones. A comparison of their time course with interval and PST-histograms from single units in colliculus and geniculate prove their intramodal specific nature. The importance of the d.c.-potential for the “objective” audiometry is demonstrated.