Document name

Hearing Loss

Document number

POL 11/2012

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.

Decibel sum of the hearing threshold levels (DSHL) 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).

Exchange rate means the maximum amount sound levels may increase above the specified criterion level if exposure time is cut in half.

Presbycusis means sensorineural hearing loss as a result of aging.

Sensorineural means hearing impairment due to damage to the cochlea (hair cells) or the cochlear (auditory) nerve.

Conductive means hearing loss due to a physical dysfunction of the sound collecting apparatus, either the bones or eardrum, but the auditory nerve is not affected.

Tinnitus means a subjective whistling, ringing, roaring or buzzing sound in the ear for which there is no objective measurement.

1. The purpose of this policy is to provide guidelines for the adjudication of traumatic and occupational noise induced hearing loss claims and PFI awards. The most current version of the American Medical Association: Guides to the Evaluation of Permanent Impairment (AMA Guide) is the Workers’ Compensation Board’s (WCB) rating schedule. These guides are used to establish the degree of hearing loss and the amount to be awarded.
2. The WCB regards occupational hearing loss as an injury and not an occupational disease.

1. Occupational hearing loss may be traumatic (acoustic trauma), noise induced, or both. The date of injury for noise induced hearing loss is the earlier of the dates the worker initially sought medical attention for the condition, or reported to the WCB. For acoustic trauma, the actual date of the injury is to be used.
2. 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 sensorineural, conductive or both.
3. Noise induced hearing loss is gradual and due to prolonged occupational exposure of excessive noise levels over a period of years (causing sensorineural impairment). To be eligible for a claim, there must be evidence of continuous occupational noise exposure for two or more years at the decibel levels and durations outlined in the chart below (taking into consideration normal time away for rest breaks), and the occupational noise exposure must be the predominate cause. In accordance with the Canadian Center for Occupational Health and Safety equivalent noise exposure standards, for every increase in noise of three decibels (Saskatchewan three decibel exchange rate) above 85 decibels, the required daily exposure time (over two or more years) required to result in lasting impairment will be reduced by half.
    

   Allowable Level Decibels (Three Decibel Exchange Rate)	Max Permitted Daily Duration (Hours)
   85	8
   88	4
   91	2
   94	1
   97	0.5
   100	0.25

   
   
    
4. Actual noise readings at the worksite are not essential, provided confirmation of exposure from the employer, industry or other valid source is available to the WCB.
5. Hearing impairment is evaluated and based on DSHL. A DSHL totalling 125 or greater in one ear qualifies for a PFI award. A DSHL totalling 105 or greater in each of both ears qualifies for a PFI award. A DSHL totalling 367 in one ear is considered to be a total loss of hearing in that ear.
6. To qualify, a noise induced hearing loss claim must be a result of hearing loss predominantly from work exposure in a high noise industry.
   1. The WCB will determine the extent of noise induced hearing loss from work-related exposure by reviewing the worker’s audiogram completed while employed or within five years of leaving employment in a high noise industry. Noise induced hearing loss does not progress when noise exposure from work ceases. Therefore, an audiogram completed while employed or within five years of leaving employment would provide an accurate work exposure reading.
   2. If no audiogram is available from while the worker is employed or in the immediate five years from leaving employment, the WCB will review the worker’s current audiogram. The WCB will consider audiogram patterns and standard occupational hearing loss calculators when determining the amount of noise induced hearing loss resulting from work-related exposure. However, the claim will not qualify if it is determined by the WCB that the hearing loss recorded on the current audiogram is predominately age related (presbycusis).
7. Hearing loss claims that are accepted as being predominately noise induced will not have a presbycusis factor deducted in determining the level of the PFI award.
8. A possible side effect of noise induced hearing loss is tinnitus. This condition will qualify a worker for a PFI award provided there is documented medical evidence that tinnitus has been long-standing, distressing, and continuous for at least two years. Where 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 hearing impairment (hearing impairment of both ears) rating.
9. 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.
10. PFI awards for hearing loss will not be considered when establishing entitlement to independence allowance.