Nonauditory effects of waterborne sound: Subjective responses during under water hearing conservation studies

Divers have reported that intense waterborne sound can be felt as well as heard. Subjective reports of nonauditory sensations were obtained from 19 divers during recent underwater hearing conservation studies. The divers were interviewed following each noise exposure trial. The waterborne exposure stimuli were warble tones (±5% center frequency) at center frequencies varying from 125 to 6000 Hz at sound-pressure levels as high as 145 dB re: 20 μPa. Exposure durations ranged from 43 s–15 min per exposure. Reports of direct effects on divers’ bodies, and effects on diver equipment were solicited. Nonauditory sensations were reported for frequencies of 1000 Hz and below, but none was reported above 1000 Hz. The lower the frequency, the lower the threshold for nonauditory sensations. At 125 Hz, sensations were first reported at a level of 104 dB re: 20 μPa. Nonauditory sensations reported were primarily vibrations felt at various locations on the divers’ bodies. Anatomical localization of sensations varied with frequency, but were not exclusively related to gas filled viscera. There were also several reports of minor effects on diving equipment. No evidence for nonauditory, physiological hazard was found during these limited exposures. [Work supported by U.S. Navy.]