RESPIRATOR PERFORMANCE RATINGS FOR SPEECH-INTELLIGIBILITY

A respirator degrades speech intelligibility and thus interferes with the ability of the wearer to communicate. The magnitude of this degrad ation is not well-studied and can vary as a function of numerous param eters. This study investigated the performance degradation of speech i ntelligibility in low-level noise for different speaker-listener dista nces and message sets (single words or predictable sentences) that occ urred while wearing a respirator compared with not wearing a respirato r. Thirteen speaker-listener pairs with normal hearing and speech were used. Speaker-listener separation distances were 0.61, 1.22, 1.83, 2. 44, 3.05, and 3.66 m (2, 4, 6, 8, 10, and 12 ft) for the respirator co ndition and 1.22, 2.44: 3.05, 6.1, 9.15, and 12.2 m (4, 8, 10, 20, 30, and 40 ft) for the no-respirator condition, The means of the scores w ere used to determine the speech performance rating for both the singl e-word and sentence comprehension tests. The performance rating expres ses the percentage of performance that can be expected while wearing a respirator compared with not wearing a respirator. Scores were interp olated linearly at distances at which no data were obtained. As expect ed, the speech performance rating was higher for the sentence comprehe nsion test than for the single-word comprehension test at each distanc e. At a distance of 12.2 m, the speech performance rating for the sent ence comprehension was 70%, For the single-word comprehension test, th e speech performance rating was zero for distances greater than 9.1 m.