Ears | Audiometry | I/O (L1 = 40 dB) | I/O (L1 = 65 dB) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2k | 3k | 4k | 6k | 2k | 3k | 4k | 6k | 2k | 3k | 4k | 6k | ||
Results expressed as mean (SD). | |||||||||||||
*Note that an increasing value for audiometry indicates worse hearing, whereas an increasing value for DPOAEs indicates a stronger response, or “better” hearing. | |||||||||||||
Control | |||||||||||||
Baseline | 114 | 7.4 (8.0) | 6.5 (6.5) | 5.9 (6.9) | 13.9 (10.8) | −15.1 (8.6) | −18.6 (8.5) | −19.4 (8.8) | −25.6 (9.1) | 1.7 (9.0) | −0.5 (7.5) | −0.7 (7.5) | −6.5 (8.9) |
Year 1 | 110 | 6.1 (7.3) | 5.1 (5.3) | 5.3 (6.5) | 14.5 (12.0) | −16.1 (9.6) | −18.7 (9.2) | −20.0 (9.1) | −25.6 (7.7) | 1.2 (8.0) | −1.5 (8.4) | −2.0 (7.8) | −6.8 (7.7) |
Year 2 | 97 | 6.4 (7.8) | 5.3 (5.4) | 4.1 (6.4) | 16.5 (11.0) | −13.9 (7.8) | −18.0 (8.2) | −20.0 (9.2) | −26.3 (7.4) | 1.6 (9.6) | 0.6 (7.1) | −0.3 (7.5) | −6.5 (8.1) |
Year 3 | 97 | 5.7 (8.1) | 5.3 (5.8) | 4.5 (6.1) | 14.3 (11.2) | −14.4 (8.0) | −18.1 (9.0) | −19.5 (8.2) | −25.2 (6.8) | 2.0 (8.3) | 0.1 (6.7) | 0.6 (7.3) | −5.3 (8.7) |
Low exposed | |||||||||||||
Baseline | 238 | 6.4 (6.7) | 8.0 (9.7) | 12.1 (14.2) | 18.2 (15.5) | −14.6 (8.2) | −19.0 (8.1) | −22.6 (8.6) | −25.0 (8.4) | 2.9 (6.5) | −1.3 (7.1) | −4.5 (7.9) | −9.9 (8.3) |
Year 1 | 172 | 7.0 (6.8) | 8.2 (11.0) | 12.9 (15.1) | 17.9 (16.3) | −15.1 (8.5) | −19.3 (8.0) | −22.2 (8.3) | −28.0 (6.9) | 0.8 (6.4) | −3.5 (7.8) | −4.9 (8.4) | −10.7 (7.9) |
Year 2 | 187 | 6.4 (7.2) | 8.2 (9.9) | 11.9 (14.5) | 17.9 (16.4) | −15.9 (8.2) | −20.2 (7.8) | −22.8 (8.2) | −27.7 (6.7) | 1.0 (7.0) | −3.6 (7.2) | −6.1 (9.0) | −10.9 (8.1) |
Year 3 | 136 | 5.9 (6.6) | 7.5 (8.1) | 11.8 (14.4) | 16.6 (13.9) | −12.5 (8.5) | −18.6 (8.1) | −22.6 (7.5) | −26.3 (6.2) | 3.4 (7.1) | −1.6 (7.5) | −5.7 (9.8) | −11.2 (8.8) |
High exposed | |||||||||||||
Baseline | 280 | 7.9 (7.6) | 9.9 (11.3) | 13.3 (16.0) | 19.4 (16.0) | −15.5 (8.1) | −19.4 (7.5) | −22.0 (8.1) | −25.5 (8.2) | 2.3 (6.8) | −1.7 (7.3) | −3.5 (8.2) | −9.3 (7.6) |
Year 1 | 242 | 8.0 (8.3) | 10.9 (12.1) | 14.0 (16.3) | 20.4 (17.2) | −15.5 (7.4) | −20.5 (7.7) | −22.8 (8.7) | −26.9 (7.1) | 1.6 (7.3) | −3.4 (7.7) | −5.2 (8.7) | −10.8 (8.5) |
Year 2 | 218 | 8.4 (8.6) | 12.7 (13.4) | 15.9 (17.7) | 21.6 (17.9) | −16.1 (7.4) | −21.1 (7.7) | −23.2 (8.1) | −27.1 (5.7) | 1.1 (7.5) | −4.2 (7.8) | −6.0 (8.9) | −11.3 (8.0) |
Year 3 | 159 | 8.1 (9.0) | 10.4 (12.5) | 12.9 (15.4) | 19.2 (15.2) | −15.8 (8.8) | −18.1 (7.8) | −22.4 (9.1) | −27.4 (6.9) | 2.2 (7.1) | −2.7 (8.6) | −4.8 (9.4) | −11.4 (8.9) |