The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker is appealing the decision made by the Workers Compensation Board ("WCB") that his claim for noise induced hearing loss was not acceptable. A hearing was held via teleconference on June 10, 2013 to consider the matter.

Issue

Whether or not the claim is acceptable.

Decision

That the claim is not acceptable.

Decision: Unanimous

Background

The worker filed a claim with the WCB for noise induced hearing loss. On his Worker Hearing Loss Report form dated February 2, 2009, the worker indicated that he first became aware of a hearing problem 10 years ago and that his hearing loss came on gradually. The worker attributed his hearing loss to the noise in his workplace environment.

The Employer Hearing Loss Report form dated February 24, 2009 indicated that the worker began employment with the firm on October 10, 1978 and that he reported his hearing difficulties to his supervisor on February 16, 2009. The employer provided the WCB with details of the worker's job duties throughout the course of his employment from 1978 through to 2009 along with a description of the tools and equipment that he used.

The worker's file consisted of audiogram reports that were reviewed by the WCB's ear, nose and throat ("ENT") consultant on May 30, 2009. The consultant commented as follows:

All the audiograms on file, dating back to 1995, show a cookie-bite configuration, with the loss being mainly in the lower frequency range. This is not typical or diagnostic of NIHL [noise induced hearing loss].

On June 8, 2009, a WCB adjudicator provided the worker with the criteria used by the WCB to establish a claim for noise induced hearing loss. She noted that the worker's audiograms were not typical or diagnostic of noise induced hearing loss and therefore his claim for hearing loss had been denied.

In a report to the WCB dated June 26, 2012, the worker's audiologist indicated that the worker was seen for an audiological re-assessment. The audiologist noted that the worker's hearing loss had increased since his 2009 audiogram. The cookie bite configuration was still present in his mid frequencies in combination with a substantial high frequency shift in the 4000-8000 Hz range bilaterally. It was the audiologist's opinion that the worker had a combination of heredity loss and noise induced high frequency loss.

On August 3, 2012, the WCB's ENT consultant reviewed the June 26, 2012 audiologist's report and stated that it did not change his opinion outlined on May 30, 2009. He stated: "The slight drop in the higher frequencies represents presbycusis and is not typical or diagnostic of NIHL."

In a further note to file dated September 4, 2012, the ENT consultant stated that the medication taken by the worker did not alter his opinion regard the cause of his hearing loss.

On September 5, 2012, the WCB advised the worker that there would be no change to the decision of June 8, 2009 based on the opinion expressed by the WCB's ENT consultant on August 3, 2012. On October 1, 2012, the worker appealed the decision to Review Office.

On November 15, 2012 Review Office confirmed that the claim was not acceptable for a noise induced hearing loss. Review Office considered the information provided by the worker's treating audiologist dated June 26, 2012 but placed more weight on the opinions expressed by the WCB's ENT consultant. Review Office concluded based on the weight of evidence that the worker did not suffer an injury arising out of and in the course of his employment. On April 9, 2012, the worker appealed Review Office's decision to the Appeal Commission and a hearing was held via teleconference on June 10, 2013.

Following the hearing, the appeal panel requested information from the WCB with respect to the criteria used to determine noise induced hearing loss via audiogram results. A response from the WCB was later received and was provided to the worker for comment. On August 8, 2013, the panel met further to discuss the case and rendered its final decision.

Reasons

Applicable Legislation and Policy

In considering appeals, the Appeal Commission and its panels are bound by The Workers Compensation Act (the “Act”), regulations and policies of the Board of Directors.

Subsections 1(1) and 4(1) of the Act set out the circumstances under which claims for injuries can be accepted by the WCB, and state that the worker must have suffered an injury by accident that arose out of and in the course of employment. Once such an injury has been established, the worker is entitled to the benefits provided under the Act. Hearing loss claims are adjudicated by the WCB as occupational disease claims.

The Board established Policy 44.20.50.20 Hearing Loss (the “Hearing Loss Policy”) to address claims arising from exposure to occupational noise that cause hearing loss.

The Hearing Loss Policy states, in part:

1) Noise induced hearing loss occurs gradually – often over several years – and most hearing-loss claims do not involve a loss of earnings. For these reasons, it can be difficult to determine when the impairment began. For the purposes of this policy, the date of the accident will be:

a) The date a loss of earnings has occurred, or

b) The date of an audiogram which shows evidence of noise-induced hearing loss…

3) Not all hearing loss is caused by exposure to noise at work. The WCB will be satisfied that hearing loss occurred at work when a worker is exposed to noxious noise at work for a minimum of two years, based generally upon an average of 85 decibels for 8 hours of exposure on a daily basis. For every increase in noise level of 3 decibels, the required exposure time will be reduced by half.

The issue to be determined by this panel deals with causation and whether the worker’s hearing loss arose out of and in the course of employment.

Worker’s Position

The worker was self-represented at the hearing. He stated that his 33 years of employment had been in a high-noise environment. During that period, he had been exposed to high levels of noise on a regular daily basis. The worker indicated that at a follow-up hearing test in June 2012 he had been advised by the testing audiologist that a “substantial shift in the higher frequencies” was indicative of a noise-exposure loss. The worker stated that many of his co-workers who experienced similar hearing loss had been approved for hearing aids. The worker relies on the June 26, 2012 report provided by his audiologist which states that his hearing loss is due in part to noise-induced hearing loss, based on his test results.

Employer’s Position

The employer did not participate in the appeal.

Analysis

The issue for this panel to determine is whether the worker’s claim for hearing loss is acceptable. In order to find the claim acceptable, the panel must find, on a balance of probabilities, that the worker's hearing loss arose out of and in the course of his employment.

During the hearing, the worker reviewed the types of workplace noise to which he was exposed during the course of his employment. At various periods during his employment, he was exposed to considerable noise while working as a machine operator or a hands-on foreman. He advised that during the period from approximately 1978 to 1992, a considerable amount of time was spent travelling in “notoriously” loud “motor cars” that carried workers from one area to another. In approximately 1992, the “motor cars” were replaced by service trucks. While the trucks were quieter, they were equipped with new hydraulic systems that powered a variety of hydraulic tools. This resulted in the truck having to “rev at a high noise level" described as a high whine, in order to power hydraulic tools that were themselves extremely noisy. Given that the truck was powering the tools, the worker was “tied to the truck” and therefore had to work in close proximity to such noise. The worker advised that he had to raise his voice to be heard by other workers. The source of the workplace noise had essentially shifted from travelling from site to site to the noise ultimately experienced while working at the site.

Hearing protection was provided, but it had not been particularly well-promoted during the earlier years of the worker’s employment.

The worker stated that while he could not establish that his hearing loss was noise-induced, he believed that the loss would have been made worse by his work environment. He queried how one could say that the noisy workplace environment had not played a part in his hearing loss.

Following the hearing, this panel requested that the WCB medical consultant, who is an ENT specialist, respond to questions posed by the panel. The ENT noted the following; in part:

For an audiogram to be typical or diagnostic of NIHL, it should have the following characteristics:

1. The hearing loss is sensorineural in nature.

b. The hearing loss is typically bilateral since most noise exposures are symmetric, unless it has been proven that one ear has been exposed to more noise than the other.

c. The first sign of NIHL is notching of the audiogram at the high frequencies of 3000, 4000 or 6000 Hz with recovery at 8000 Hz (Fig. 1). This notch typically develops at one of these frequencies and affects adjacent frequencies with continued noise exposure (Fig. 2). This, together with the effects of aging, may reduce the prominence of the "notch" (Fig. 3). Therefore, in older individuals, the effects of noise may be difficult to distinguish from age-related hearing loss (presbycusis) without access to previous audiograms…

d. In early NIHL, the average hearing thresholds at the lower frequencies of 500, 100 and 2000 are much better than the average thresholds at 3000, 4000 and 6000 Hz, and the hearing level at 8000 Hz is usually better than the deepest part of the notch. This notching is in contrast to presbycusis, which also produces high-frequency hearing loss but in a down sloping pattern without recovery at 8000 Hz…

e. Noise exposure alone usually does not produce a loss greater than 75 dB in high frequencies and greater than 40 dB in lower frequencies. Nevertheless, individuals with non-NIHL, such as presbycusis, may have hearing threshold levels in excess of these values.

The ENT was specifically asked if there were indicators in the worker’s audiogram results that suggest NIHL. His response was:

No. All the audiograms on [the worker’s] file from 1995 to 2012 show a typical cookie-bite configuration. The audiologist, in her report dated March 2, 2009, indicated the same and she described the hearing loss as a cookie bite hearing loss.

Cookie-Bite loss looks like someone took a bite out of the top of the audiogram. Thus, the curve is higher at both the lower and higher frequencies and lower in the middle frequencies (Fig 4).

Cookie-bite hearing loss is usually hereditary or genetic. It is never caused by noise exposure.

In all [the worker’s] audiograms, the greater hearing loss is in the 500, 1000 and 2000 frequencies with the average being much worse than the average of 3000, 4000 and 6000 Hz frequencies.

Usually, in NIHL, 4000 Hz is the worst frequency. In [the worker’s] audiograms, 4000 Hz is his best frequency.

The audiogram of 1995 shows a slight notch at 6000 Hz in the left ear only. This notch disappeared in the subsequent audiograms dated 1997, 1999 and 2001. This notch shows up again in the audiogram of 2004, but disappeared in the subsequent audiograms of 2009 and 2012. Obviously, this notch is not permanent and could represent a temporary threshold shift that recovered in the subsequent audiograms.

The ENT was further asked if noise exposure contribute to the worker’s hearing loss. His response was:

No. Based on the above information and the configuration of the audiograms on file, I cannot conclude that noise exposure has contributed to [the worker’s] hearing loss.

The panel gives greater weight to the opinion of the ENT medical consultant than it does to that of the testing audiologist, and adopts his conclusion. In particular, the panel accepts the more detailed technical analysis provided based on his more extensive medical training and experience. The panel also turned its mind to the worker's exposure history. The panel finds the workplace exposures identified by the worker did not meet the WCB policy requirements of two years of continuous exposure to levels of noxious noise. The panel notes that the worker's work history was outdoors, rather than in confined space which would increase amplification and reverberation. Again, this is confirmed by the audiological testing which does not establish a permanent noise induced hearing loss.

In order for this claim to be successful, we would need to find that the worker suffered from an employment related noise-induced hearing loss. The medical evidence does not support such a finding, but instead, points to the hearing loss as not having been caused by workplace noise. The worker's history of a lack of exposure to noxious noise also points to another cause of his hearing loss. For the reasons noted above, we find that the worker’s claim for noise-induced hearing loss is not acceptable.

Panel Members

D. Kells, Presiding Officer
A. Finkel, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kosc

D. Kells - Presiding Officer

Signed at Winnipeg this 23rd day of September, 2013