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2019 ITU Kaleidoscope Academic Conference
the importance of the incorporation of user voice to promote
access, engagement and hearing health decision making. An US APHC: Damage occurs at 85 dBA or
additional consideration for app development is the more for continuous noise
incorporation of the WHO recommended Principles of
Digital Development [16] to further facilitate access and ease DoD HCE: Limit exposure exceeding 80
of use. Overall, the Hearing Health app could serve to – 85 dBA
provide a ‘digital health intervention’ for supporting hearing
healthcare. The available US and UN safe listening standards can be
segmented into three main categories: recreational,
2.2 App functionalities occupational, and military, as summarized in Table 1. The
standards are reflective of anticipated noise exposures in
The functioning of the Hearing Health app is based on: daily life with associated standards for hearing safety.
• daily sound exposures, as a summation of A-weighted Of the various standards, only the OSHA PEL and the WHO-
sound pressure levels (SPL in dBA) over time, based on ITU provide methodology for computing A-weighted sound
daily activities related to occupation, lifestyle and pressure level exposures. The resultant exposure
recreational choices; assessments can be used to address the noise limits
• estimation of the user’s cumulative daily exposure vs recommended by the other agencies listed in Table 1. Also,
sound dosage from recommended US (occupational, OSHA recommends that when daily noise exposure is
military) and UN (WHO-ITU) safe listening standards; composed of at least two periods of different sound pressure
• risk notifications about unsafe noise exposures; levels, the combined effect should be considered, rather than
• incorporation of user voice on engagement strategies; the individual effect of each. The exposure calculations take
• option for connection to a personal hearing device, e.g., this recommendation into account.
PSAP, via Bluetooth.
The Hearing Health app calculates the user’s occupational
App functionalities and user voice implementation were environmental exposure compared to OSHA’s PEL exposure
based on user feedback from a wide demographic. using the following formula:
2.3 Evaluation and incorporation of safe listening = 100 ∗ ( (1) + (2) + . . . + ( ) ) (1)
standards (1) (2) ( )
where C(n) indicates the total time of exposure at a specific
Table 1 – US and UN safe listening standards [5-7, 9-13] noise level. D represents what percentage of the OSHA
standard for daily noise exposure to which the user has
Exposure Standard already been exposed.
type
T(n) indicates the reference duration calculated by:
Recreational WHO-ITU (H.870) 8
(audio ( ) = 2 ( −90)/5 (2)
device) Adults: 80 dBA for 40 hours a week
where L is the A-weighted SPL of the exposure.
Children: 75 dBA for 40 hours a week
For users whose sound exposure is primarily through audio
devices, the app calculates audio exposure via the WHO-ITU
Occupational CDC, NIOSH Recommended Exposure standard. The exposure is calculated by
Level (REL): 85 dBA over 8 hours daily
2 2
∫ ( ( )) t (3)
OSHA Permissible Exposure Limit 1
(PEL): 90 dBA over 9 hours daily
where pa(t) is the A-weighted SPL in Pa. This exposure is
then compared to WHO’s weekly dose of 1.6 pa h for adults
2
NIDCD: ≤ 70 dBA is safe; > 85 dBA is and 0.51 pa h for sensitive users (i.e. children).
2
damaging over time
The remaining occupational and military standards described
Military US ARL: SPL shall not exceed an 8- in Table 1 prescribe noise dosages over a set amount of time.
hour time weighted average of 85 dBA Therefore, to address the standards specified for an 8-hour
time period (CDC, Military), the cumulative exposures can
be calculated using the OSHA formula. To compensate for
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