Contribution to the Study of Auditory Fatigue

Fatigue and other effects of 3 minutes of strong (105 db) acoustic stimulation were studied. Four combinations of fatiguing sound (white noise or 2‐kc tone) and test frequency (3 or 4 kc) were each used twice for each of 24 Ss. Mean threshold recovery, functions closely resembled many of the individual functions reported by Hirsh and Ward and confirmed the phenomenon they called “bounce” however, many individual functions, like Hood's, were monotonic. Largest inter‐subject and smallest intra‐subject variability were associated with the noise/4000 combination. Ss differed considerably with respect to general fatiguability and recovery rate, and they tended to remain in the same rank order throughout the post‐stimulatory period. There was a positive but low relationship between the fatigue a S displayed under one condition and what he displayed after the same recovery time under another condition; the relationship was generally highest after the first 3 minutes following stimulation. Many individual recovery charts displayed roughness indicative of a recurring disturbance of considerably shorter duration than the bounce effect. There was no obvious relationship between threshold shift and display of either roughness or bounce; nor could these latter two phenomena be entirely accounted for by tinnitus.