Abstract
Background: The accuracy of audiometric testing is critically dependent on a controlled acoustic environment to prevent ambient noise from masking test stimuli. Traditional sound-treated booths, while effective, present limitations in cost, portability, and accessibility. The Kuduwave audiometer is an innovative, portable diagnostic system designed for accurate hearing assessments outside of such booths, primarily due to its advanced passive sound attenuation.
Objective: This white paper defines and calculates Kuduwave-specific Maximum Permissible Ambient Noise Levels (MPANLs) according to ANSI S3.1-1999 (R2013), BS EN ISO 8253-1:2010, and SANS 10182:2006 for air and bone conduction audiometry. The Kuduwave’s unique dual passive attenuation system necessitates these specific calculations, a practice supported by the framework of audiometric standards. For air conduction, it considers minimum test thresholds (0 dB HL, 15 dB HL, 25 dB HL). For bone conduction, MPANLs are presented for 0 dB HL, as this is the standard clinical practice. Calculations consider different eartips (foam, silicone). Critically, this expanded paper proposes a novel, unified global MPANL standard specifically for the Kuduwave audiometer, synthesizing the most protective aspects of existing international standards using a common baseline for both air and bone conduction calculations within this unified framework.
Methods: Kuduwave-specific MPANLs are calculated by adding the device’s empirically determined combined sound attenuation (earcup + eartip) to the “ears not covered” or equivalent unoccluded baseline MPANLs from each standard. Adjustments for 15 dB HL and 25 dB HL are made for air conduction testing. The proposed unified standard derives a single consolidated, most stringent “ears not covered” baseline from the three aforementioned standards; Kuduwave’s attenuation is then applied to this common baseline to determine unified MPANLs for both air conduction (0, 15, and 25 dB HL) and bone conduction (0 dB HL), maintaining distinctions for eartip type.
Results: The Kuduwave audiometer permits reliable hearing assessments in ambient noise levels considerably higher than those acceptable for unoccluded or conventional supra-aural earphone testing. Distinct MPANL tables are presented for each standard and eartip. The proposed unified Kuduwave MPANLs offer a single, globally applicable set of values, aiming for maximum test validity by adopting a conservative common baseline.
Conclusion: The established Kuduwave-specific MPANLs and the newly proposed unified global MPANL standard provide robust, evidence-based guidance for clinicians and researchers. This work supports the Kuduwave’s role in increasing access to reliable hearing healthcare in diverse settings. The unified standard, in particular, offers a path towards global harmonization and simplified, consistent application of the Kuduwave, potentially serving as a model for other advanced audiometric technologies.