One of the frequently quoted reasons for the rejection of hearing aids is amplification of background noise. The relationship between hearing aid use and toleration of background noise was assessed. Four groups of elderly subjects (at least 65 years old) and one group of young subjects with normal hearing participated in the study. Each group consisted of 15 subjects. The young subjects and elderly subjects in one group with relatively good hearing were tested for comparison with the hearing-impaired subjects. Elderly subjects in the three remaining groups had acquired hearing losses and had been fitted with hearing aids. The subjects were assigned to three groups on the basis of hearing aid use: full-time users, part-time users, and nonusers. The amount of background noise tolerated when listening to speech was tested. The speech stimulus was a story read by a woman and set at an individually chosen most comfortable level. The maskers were a babble of voices, speech-spectrum noise, traffic noise, music, and the noise of a pneumatic drill. There was a significant interaction between groups and noises. The full-time users tolerated significantly higher levels of music and speech-spectrum noise than part-time users and nonusers. In addition, the full-time users, but not the part-time users, assessed themselves as less handicapped in everyday functions when they wore hearing aids than when they did not wear their hearing aids
Vibration Behavior during Underground Drilling Based on an Innovative Measurement Method and the Application
