Document name

Hearing Loss

Document number

POL 01/2023

Decibel means a unit of measurement expressing the relative intensity (loudness) of sound.

Hertz means a unit of frequency equal to one cycle per second and is related to the pitch of the sound.

1. The Workers’ Compensation Board (WCB) has exclusive jurisdiction to determine all matters arising pursuant to The Workers’ Compensation Act, 2013, specifically (Section 20):
   1. Whether any condition or death was caused by an injury,
   2. Whether an injury has arisen out of and in the course of employment, and
   3. The existence, degree and permanence of any functional impairment resulting from an injury.
2. The WCB is required to make its decisions on the real merits and justice of each case but may consider its policy directives (Section 23).
3. WCB uses the most current version of the American Medical Association: Guides to the Evaluation of Permanent Impairment (AMA Guide) as the rating schedule for establishing the degree of permanent functional impairment (PFI) as a result of the hearing loss.
4. The WCB considers occupational hearing loss an injury and not an occupational disease.
5. While the WCB does not assume any responsibility for a worker’s pre-existing condition, the WCB will determine if a work-related injury resulted in either an aggravation or acceleration of a worker’s pre-existing condition (Section 49).

1. The WCB will determine if a hearing loss injury was a result of a work-related incident,  noise exposure during employment, or while performing activities for the purpose of their employment. 
2. WCB will make decisions on the real merits and justice of each situation based on evidence. Decisions will be made in accordance with the conclusion that is more likely (i.e., more evidence for the fact than against).
3. Occupational hearing loss may be:
   1. Traumatic (acoustic trauma),
   2. Noise-induced, or
   3. Both.

Traumatic hearing loss

4. Traumatic hearing loss is usually sudden or acute and traceable to a specific work-related incident (e.g., exposure to a loud burst of sound, excessive pressure levels or injury such as basal skull fracture). The hearing impairment may be:
   1. Sensorineural, which is due to a damage to the cochlea (hair cells) or the cochlear (auditory) nerve,
   2. Conductive, which is due to a physical dysfunction of the sound collecting apparatus, either the bones or eardrum, but the auditory nerve is not affected, or 
   3. Both.
5. For acoustic trauma, the actual date of the injury is to be used. 
6. Traumatic noise induced hearing loss can either be monaural (affects one ear) or binaural (affects both ears), and usually affects one ear more than the other.

Noise-induced hearing loss (NIHL)

7. NIHL is gradual and due to prolonged occupational exposure of excessive noise levels over a period of years (causing sensorineural impairment). To be considered a compensable injury:
   1. There must be evidence of continuous occupational noise exposure for two or more years equal to or above the decibel levels and durations outlined in the chart below (taking into consideration normal time away for rest breaks), 
   2. The occupational noise exposure must be, more likely than not, the dominant cause of the worker’s injury (i.e., having the most significant impact in bringing about the loss), and
   3. An audiogram confirms NIHL:
      1. At any time in the worker’s employment years in a high noise industry,
      2. Within five years of leaving employment in a high noise industry (i.e., NIHL does not progress when noise exposure from work ceases), or 
      3. If no audiogram is available from while the worker is employed or in the immediate five years after leaving employment in a high noise industry, the WCB will review the worker’s current audiogram. However, the claim will not qualify if it is determined that it is more likely that NIHL is not the dominant cause of hearing loss on the current audiogram.
8. In accordance with the Canadian Center for Occupational Health and Safety (CCOHS), the allowed maximum exposure time is calculated by using an exchange rate, which is the amount by which the permitted sound level may increase if the exposure time is cut in half. The following shows the allowable decibel levels at a three-decibel exchange rate (Saskatchewan’s limit) and the maximum daily duration.

9. For noise-induced hearing loss (NIHL), the date of injury is the earlier of:
   1. The date the worker initially sought medical attention for the condition, or 
   2. The date the worker reported the work-related hearing loss to the WCB.
10. NIHL is symmetrical, which means hearing loss is equal in both ears. In some cases, asymmetrical hearing loss can occur from greater noise exposure on one side or an individual sensitivity difference in each ear.
    1. WCB defines asymmetry as 15 decibels of difference in each of two tones using the tones 1000hz, 2000hz, 3000hz, 4000hz and 6000hz (difference must be in same direction).
    2. If hearing loss in one ear is worse than the other ear, and there is NIHL in the better ear, WCB considers that there is an equal NIHL in the worse ear and will consider coverage for hearing aids in both ears, if medically recommended.

Permanent functional impairment (PFI) award

11. PFI will be determined in accordance with The American Medical Association Guides to the Evaluation of Permanent Impairment (AMA Guides) and POL 23/2010, Permanent Functional Impairment (PFI) – General.
12. Hearing impairment is evaluated and based on a decibel sum of the hearing threshold levels (DSHL), which means the sum of the minimum volumes detected during hearing tests, measured in decibels using a pure tone audiometer. For the purpose of assessing PFI awards, hearing tests are done at four frequency levels (500, 1,000, 2,000 and 3,000 Hertz). 
13. To qualify for a PFI award:
    1. There must either be:
       1. A DSHL totalling 125 or greater in one ear.
       2. A DSHL totalling 105 or greater in each of both ears, or
       3. A DSHL totalling 367 in one ear, which is considered to be a total loss of hearing in that ear.
    2. NIHL must be a result of hearing loss dominantly from work exposure in a high noise industry based on an audiogram that confirms NIHL:
       1. At any time in the worker’s employment years in a high noise industry,
       2. Within five years of leaving employment in a high noise industry (i.e., NIHL does not progress when noise exposure from work ceases), or
       3. If no audiogram is available from while the worker is employed or in the immediate five years after leaving employment in a high noise industry, the WCB will review the worker’s current audiogram. However, the claim will not qualify if it is determined that it is more likely that NIHL is not the dominant cause of hearing loss on the current audiogram, considering the overall findings and the calculated expected loss from presbycusis (hearing loss due to aging) at the time of the audiogram.
       If hearing loss in one ear is worse than the other ear, and there is NIHL in the better ear, WCB considers that there is an equal NIHL in the worse ear, and PFI will apply to both ears.
14. Hearing loss claims that are accepted as being dominantly noise-induced will not have a presbycusis (aging) factor deducted in determining the level of the PFI award.
15. NIHL may have a side effect called tinnitus, which is a subjective whistling, ringing, roaring or buzzing sound in the ear for which there is no objective measurement. 
    1. A worker with this condition may qualify for a PFI award if there is documented medical evidence that tinnitus has been long-standing, distressing, and continuous for at least two years. 
    2. If tinnitus has been caused by a work-related injury or occupational hearing loss, a rating of up to five per cent may be added to the worker’s binaural (both ears) hearing impairment rating. 

Hearing aids

16. If occupational noise exposure or a traumatic work-related injury has resulted in the need for hearing instruments, coverage for the instruments and batteries should be provided in accordance with PRO 57/2017, Hearing Services.
17. As WCB already covers aids and support systems as required for the compensable injury, independence allowance will not be paid on hearing loss claims.

Pre-existing conditions

18. The medical record obtained from the service provider, care giver or the worker should include a history of any prior hearing loss from disease or injury.
19. Entitlement for a work-related hearing loss will not be denied due to the existence of a pre-existing condition. However, the WCB does not assume any responsibility for a worker’s pre-existing condition.
20. The WCB will determine if a work-related noise exposure resulted in either an aggravation or acceleration of a worker’s pre-existing condition in accordance with POL 12/2017, Pre Existing Conditions – Aggravation or Acceleration.

Interjurisdictional exposure

21. All hearing loss claims are to be prorated to provide coverage for only the portion of hearing loss caused by exposure in a Saskatchewan industry, except where an interprovincial agreement for occupational noise-induced hearing loss exists.