Workers are entitled to benefits for traumatic hearing loss that results from a work-related accident.
Traumatic hearing loss (THL) is hearing loss of sudden onset experienced after an acute trauma such as*
- exposure to noise from an explosion (acoustic trauma)
- direct trauma to the ear causing damage
- trauma to the head resulting in a severe concussion, or
- exposure to an ototoxic (toxic to the ear) drug or chemical.
*Phaneuf, R. and R. Hetu: An epidemiological perspective of the causes of hearing loss among industrial workers. J. Otolaryngol. 19:31-40, 1990.
Assessing permanent impairment
Maximum medical recovery
The WSIB assesses a worker's permanent impairment from traumatic hearing loss when maximum medical recovery (MMR) has occurred (see 11-01-05, Determining Maximum Medical Recovery (MMR)). Since the healing time after a trauma varies considerably -- depending on the type of injury -- medical confirmation of MMR is needed. A period as long as 6 months to a year may be required to ensure that MMR has occurred.
The WSIB rates the worker's permanent impairment using the prescribed rating schedule (AMA Guides).** The permanent impairment rating is not affected by any improvement in hearing attained with hearing aids-testing is done without aids. Average hearing losses are never rounded (up or down) before calculating the permanent impairment using the AMA Guides. To determine the final permanent impairment rating when more than one work-related permanent impairment is present, the WSIB combines the ratings for each impairment, using the AMA Guides Combined Values Chart.
** American Medical Association Guides to the Evaluation of Permanent Impairment, Third Edition(Revised).
NEL & pre-existing hearing loss
To determine the non-economic loss (NEL) benefit for workers who have a documented pre-existing hearing loss, the WSIB uses the most recent pre-injury measurement (e.g., audiogram) so it can subtract the percentage permanent impairment of the pre-existing condition from the percentage of the post injury permanent impairment.
Occupational noise-induced hearing loss
If a worker has pre-existing occupational noise-induced hearing loss (NIHL), the WSIB sets up separate claims: one for the NIHL (see 16-01-03, Occupational Noise-Induced Hearing Loss, and 16-01-04, Noise-Induced Hearing Loss, on/after January 2, 1990); and one for the THL.
If a recent pre-injury audiogram is not available, and workers are over 60 years of age, the WSIB applies a factor for presbycusis (age-related hearing loss) by
- determining the average decibel (dB) hearing loss at 4 frequencies (500, 1000, 2000 and 3000Hz), and
- subtracting one-half (0.5) dB from the post-injury permanent hearing loss for every year a worker's age is more than 60.
This policy applies to all accidents occurring on or after January 2, 1990.
This document replaces 03-03-02.