The effects of moderately intense impact and continuous noise on sensory-perceptual functions and on various task performances dependent on those functions are studied in male student volunteers to determine whether present occupational noise limits protecting hearing are adequate for other consequences of noise. Continuous noise of 105 to 110 decibels (A) and impact noise of 136 decibels, both within the NIOSH and OSHA exposure limits, only significantly affect pupil size, detection of peripheral stimuli, critical flicker fusion and dark adaptation. No significant effects are produced on visual acuity, visual threshold, visual tracking, visual reaction time, stereopsis, warm and cool thresholds and vibrotactile and two- point thresholds and vestibular kinesthetic parameters. Only a rapidly adapting increase in pupil size is noted at 105 decibels (A) with longer exposures of 30 minutes. No differences are found between the effects of continuous noise, impact noise and relative quiet on peripheral signal detection, detection of flicker and performance of the Multiple Performance Battery test. Continuous and impact noise impairs tracking performance but not extended watchkeeping when both tasks are performed simultaneously. While the effects of noise on the tracking task is considered to have some implications to safety, generally, little concern is suggested for non-auditory sensory losses caused by noise conditions meeting hearing conservation limits.
NIOSH-Author; NIOSH-Contract; Contract-099-73-0022; Noise-pollution; Noise-levels; Standards; Sensory-processes; Sensory-thresholds; Sensory-perceptual-processes; Peripheral-vision; Night-vision; Tactile-sensitivity; Vibration-perception; Work-performance; Thermoperception; Physiological-response; Perception