[A study of damaged acoustic biopotentials in guinea pigs following exposure to white noise].

62 guinea-pigs were treated twice exposed to white noise, 105 dB SPL, 20 to 20 000 cps for 40 minutes with a break of 24 hours in between. The cochlear microphonics (CM), the compound action potentials of the acoustic nerve (NAP) and the slow evoked potentials (SEP) were recorded. There were different degrees of damage to be seen in the acoustic biopotentials. The CM showed little damages only whereas the compound action potentials of the hearing nerve showed significant impairments in excitation and in adaptation. In the SEP excitation was decreased. From this, we may conclude that the CM must not be the only criterion for judging damages in the acoustic system after acoustic trauma. Furthermore we see that the central acoustic pathway is capable to compensate peripheric hearing damages within a short time. An additional exposure to noise does not necessarily add or cumulate the degrees of damage.