[Effect of ipsilateral, contralateral and binaural roaring noise on brain stem potentials in the guinea pig]

On ipsilateral masking the individual potentials showed reduced amplitudes with increasing noise level, the latency of the potential PI increased and the interval PI/PIV shortened. Compared to ipsilateral masking the potential PIV exhibited a significant minor decrease in amplitude at binaural noise presentation. At contralateral masking the peaks PI and PIII showed a reduced potential size with noise levels above 50 dB, which also produced significant changes in latency. Against that the potential PIV exhibited a significant decrease in amplitude already at noise levels above 30 dB. The results are discussed in the light of central masking and their clinical relevance.