Signal detection capability during uninterrupted full face-piece respirator wear

This study investigated the differences between conditions of full face-pie ce respirator wear and no respirator wear over 9 h on subject ability to de tect stimuli dispersed throughout the visual field. Signal detection was as sessed at the beginning of each trial and after 1, 3, 5, 7 and 9 h of testi ng in six male and three female subjects by measuring response times to 32 randomly presented stimulus lights located within a perimeter designed spec ifically for this purpose. Average reaction time increased with greater per ipheralization of the light signals within each experimental condition. Gro up mean reaction time for each peripheral ring of stimuli (12, 38, 64 and 9 0 degrees) showed that impairments were significantly greater for the respi rator wear condition compared with the control condition at all peripheral stimulus locations. For the unmasked condition, female subjects demonstrate d significantly faster response times than males at peripheral stimulus loc ations of 12 degrees (p < 0.002), 64 degrees (p < 0.001), and 90 degrees (p < 0.01). However, respirator wear resulted in comparable response times be tween sexes for each peripheral stimulus ring with the exception of stimuli located 12 degrees from the perimeter's centre. No progressive effect of r espirator wear on signal detection capability over the duration of the test was observed, suggesting that the degradation of signal detection capabili ty caused by full face-piece respirator wear occurs immediately and persist s throughout the period of wear. The findings of this study emphasize that decreased operational effectiveness in situations requiring full face-piece respirator wear should be expected.