Effects of a neoprene wetsuit hood on low‐frequency underwater hearing thresholds

In an effort to create guidelines for exposure to low‐frequency underwater sound, it is necessary to obtain population data on the minimal detectable sound‐pressure level at these frequencies. Underwater hearing thresholds were obtained from 15 male and 5 female recreational SCUBA divers with and without a 3‐mm wetsuit hood. Dives were conducted at a 1‐m depth in a large quiet anechoic pool. A J13 transducer was located 4 m directly below the subject. Thresholds were determined using two‐interval forced‐choice with a 0.71 probability of positive response at convergence. A 1‐s pure tone was presented with a 20‐ms rise and fall at 100, 200, 250, 300, 400, and 500 Hz. Results indicate there was no difference in thresholds between male and female divers. Without a wetsuit hood, mean thresholds decreased from 99 dB (s.d. 6 dB) re: 0.000 001 Pa at 100 Hz to 85 dB (s.d. 10 dB) at 500 Hz. Thresholds were statistically similar at 100 to 300 Hz with and without the wetsuit hood, but were significantly increased ...