title: Speech intelligibility in and speech interference levels of traffic noise in hearing-impaired and normal listeners.
abstract: Speech intelligibility (phonetically balanced monosyllables = PB words) in traffic-like noise (random noise) as well as the speech interference levels (75% intelligibility) of this noise were investigated in three common listening situations, two indoors and one outdoors. A total of 279 persons were examined; 56 had normal hearing, 90 a presbycusic-type hearing loss, 95 noise-induced hearing loss, and 38 conductive hearing loss. In the indoor situation the hearing-impaired groups mainly retained their intelligibility in 40 dBA. Lowering of the noise level to less than 40 dBA resulted in only a minor, mostly insignificant improvement in speech intelligibility. Normal-hearing listeners maintained good speech intelligibility in the outdoor listening situation with noise levels up to 60 dBA, without lip-reading. For hearing-impaired groups, representing more than 1/2 million (8% of the population) people in Sweden, with hearing loss due to age and/or noise, the noise level outdoors must be lowered to 45 dBA in order to achieve good speech intelligibility at 1 m, without lip-reading.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001299:Audiometry; D005260:Female; D034381:Hearing Loss; D006314:Hearing Loss, Conductive; D006317:Hearing Loss, Noise-Induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise; D009624:Noise, Transportation; D011304:Presbycusis; D013067:Speech Perception