[Implantation technics for long-term recording of the compound action potentials in the guinea pig, Cavia porcellus. A comparison of methods].

Long-term recordings of the compound action potential of the acoustic nerve of young, pigmented guinea pigs were carried out by two different techniques of implantation. The electrodes were inserted either by way of the mastoid process into the bony recess above the round window or they were introduced into the facial canal via the stylomastoid foramen. Before and after each implantation, special tests (Preyer-reflex, otoscopy, impedance audiometry) were performed for preliminary selection of the animals and to discover postoperative induced disturbances of sound conduction in the middle ear. These tests showed that the proportion of operatively induced middle ear inflammations was reduced from 24 to 10%, if electrodes were implanted into the facial canal.