Auditory research platform : twenty-four hour in-ear dosimetry

Abstract

Noise induced hearing loss (NIHL) is permanent and irreversible, yet completely preventable. It remains to be one of the most common health and safety diseases in the workplace and is an increasing concern in daily urban life and recreational activities, such as live music, bars & nightclubs, and even personal media players (PMPs). Conventional ‘personal’ noise dosimeters do not easily interface with PMPs, communication devices, and HPDs, nor are they meant for 24-hour use. Not only is it quite difficult to keep track of noise exposure accumulated over a 24-hour period; there are few guidelines to follow. Current legislation is designed for 8-hour work-shifts and based on a 16-hour recovery period in a ‘relative quite’ environment (<75 dB(A)). In an effort to increase hearing protection compliance in dangerously noisy environments two common issues are addressed: 24-hour tracking of effective individual noise exposure level, including communication or PMPs, and tracking proper fit of hearing protection devices (HPDs). The objective of this thesis is assessing the feasibility of designing a device capable of monitoring comprehensive 24-hour in-ear noise dosimetry, while interfacing with personal music players (PMPs) or communication devices. This thesis also proposes a novel algorithm for 24-hour (personal/individual/in-ear) noise dosimetry including auditory recovery while providing an open-source framework of hardware and software tools to encourage further development in this area. A custom in-ear open-source hardware ‘Auditory Research Platform’ (ARP) and an open-source Matlab ‘Dosimetry Toolbox’ have been developed for this purpose. The ARP hardware is an embedded digital signal processing system contained within a palm-sized belt-pack ready to interface with PMP, communication devices, and custom HPDs, all controllable with an Android device. The Matlab Dosimetry Toolbox is compatible with a third party iOS application and is intended to facilitate the creation of a personal noise exposure database while visualizing the results. This Master degree thesis discusses the development of the hardware and software while identifying instrumentation challenges and highlighting several key research questions related to the risk assessment of NIHL. Preliminary laboratory studies are presented and the real-life usability of such a platform is discussed. The results of this work can be used to enable further studies revisiting damage risk criteria and further research into the underlying mechanisms of NIHL such as: recovery rate, effective silence, own voice contribution, and ultimately individual susceptibility.

Date	1 Aug 2016
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Jérémie Voix (Supervisor)