Development of an S3/SC1 standard for auditory evoked potential hearing tests in toothed whales

Abstract

The National Marine Fisheries service regulates the impact of anthropogenic ocean noise to marine mammals. Other government and commercial groups that produce ocean noise are subject to regulation. Both groups desire greater knowledge of hearing in marine mammals to better predict, mitigate, and regulate noise exposure. Auditory evoked potential (AEP) hearing tests have become a primary method by which hearing tests are performed in toothed whales (e.g., dolphins, porpoises). The synthesis of AEP data to address noise impacts to marine mammals is limited, in part, because of the variability between AEP thresholds measured by different researchers and laboratories using different methodologies. Methodological differences exist for AEP detection, threshold estimation, calibration, and stimulus delivery. Threshold variability could be reduced through standardization of AEP hearing test methods, which is desired by regulatory agencies and sound producers. An S3/SC1 standard for AEP hearing test methods in toothed whales has been initiated to address this need. The draft standard will be submitted to ANSI for consideration by the end of 2017. Adoption of the standard internationally would further improve threshold comparability by ensuring researchers globally utilize the same methods. The process should increase AEP data reliability for purposes of addressing ocean noise issues.