[Short-term acoustic adaptation as a measure of the resistance of the hearing system to noise exposure].

The typological features of short-term acoustic adaptation (STAA) and its applicability for evaluating the hearing resistance to noise effects were investigated in those working in a noisy environment. The experiments were carried out on 29 subjects with normal hearing and 46 patients with neurosensory hypoacusis, including 25 patients with occupational hypoacusis. The STAA magnitude was evaluated as the difference between the hearing threshold of the 20 msec signal paired with a preceding adapting signal or without it. The duration of the adapting signal was in the range 20-1000 msec and its intensity was 40 dB over the hearing threshold. The signals were applied at 50 msec intervals. The STAA value was 5-25 dB in 90% normal subjects. In the patients with occupational hypoacusis, the hearing degradation increased as STAA declined. The patients with common neurosensory hypoacusis did not show such a relationship. It is recommended to use STAA as a measure of man's hearing resistance to noise effects.