The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker disagrees with the decision made by the Workers Compensation Board ("WCB") that his permanent partial disability award should be based on the results of his cortical evoked responses. A hearing was held via teleconference on November 14, 2013 to consider the matter.

Issue

Whether or not the worker's permanent partial disability award should be based on the audiogram results rather than the cortical evoked responses.

Decision

That the worker's permanent partial disability award should be based on the cortical evoked responses.

Decision: Unanimous

Background

The worker has an accepted claim with the WCB for noise induced hearing loss. The worker was awarded a 10.8% Permanent Partial Disability ("PPD") award for his hearing loss as well as the costs associated with hearing aids.

In 2007, the worker requested additional benefits as his hearing had worsened due to the fact that he had been exposed to further noxious noise at his workplace.

On October 20, 2007, a WCB ear, nose and throat ("ENT") consultant reviewed audiogram results dated 2003, 2005 and 2007. He stated: "Speech reception thresholds are not in agreement with the pure tone thresholds in the audiogram of Aug. 24, 2007. This raises concern regarding reliability. Probably re-testing in Saskatoon with Cortical Evoked Responses will help determine the correct thresholds."

In May 2011, the worker underwent the following tests at a hearing facility in Saskatoon: an audiogram, immittance testing, otoacoustic emissions, auditory brainstem response and cortical evoked response testing. A report outlining the test results is on file dated May 17, 2011.

On June 16, 2011, the WCB's ENT consultant reviewed the test results and calculated the worker's bilateral hearing loss as follows:

Hearing Loss - Bilateral Impairment Calculation

Poorer ear 2.3 + (5 X better ear) 9.0 = 11.3%

In a decision to the worker dated June 29, 2011, the WCB case manager stated in part:

Our ENT, following a review of the audiological information received, noted that the average loss of hearing in your right ear was determined to be 56.25 decibels while the average loss of hearing in your left ear was determined to be 57.5 decibels.

This further deterioration in your hearing due to occupational noise exposure has resulted in a change to your previous impairment award of 10.8% (effective August 4, 2000). Your impairment award for your hearing loss has now been increased to 11.3% (0.5% increase).

The worker disagreed with the case manager's decision and an appeal was filed with Review Office. The worker contended that his impairment rating should be based on the audiometric test results and not the results of the cortical evoked response testing.

On December 8, 2011, Review Office determined that the worker's rating for his hearing impairment should not be based on the audiogram results. Review Office noted that audiometry was a subjective test and was not an objective measurement. It depended on the person pushing a button or raising their hand when they hear a tone. The Cortical Auditory Evoked Potential was an objective test. A transducer such as an insert earphone, bone vibrator, or sound field speaker was used to deliver test signal to the patient. Electrodes placed onto the patient's head measured the cortical responses.

Review Office found that the worker's hearing impairment should not be based on the audiogram results but should be based on the Cortical Evoked Potential testing. On July 28, 2013, the worker appealed Review Office's decision to the Appeal Commission and a hearing was arranged.

Reasons

The worker is appealing the decision by the WCB to use Cortical Evoked Potential testing, rather than audiogram results, as the basis for establishing a PPD award for his hearing loss.

Applicable Legislation

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

At the outset, the panel notes that as the worker’s claim dates back to 1989, his benefits are to be assessed under the Act as it existed at that time. Payment of compensation for permanent disability under the Act in effect in 1989 was provided for under subsections 4(9) and 40(1), which read as follows:

Permanent disability

4(9) The board may award compensation under this Part in respect of the permanent disability suffered by a worker but without temporary total disability.

…

Permanent partial disability

40(1) Where permanent partial disability results from the injury, the board shall allow compensation in periodical payments during the lifetime of the worker sufficient, in the opinion of the board, to compensate for the physical loss occasioned by the disability, but not exceeding 75% of his average earnings.

For hearing loss claims arising on or before March 31, 2000, WCB Policy 44.90.10.02 (the “Policy”) provides guidelines for calculating impairment awards. Attached to the Policy is a Permanent Impairment Rating Schedule (the "Schedule"). The Policy provides that impairment ratings are to be established strictly in accordance with the Schedule whenever possible and reasonable. The “Impairment of Hearing” section of the Schedule provides that:

When calculating impairment due to loss of hearing, the International Standard Organization (I.S.O.) audiometric calibration will be used and the hearing will be averaged at 500, 1,000, 2,000 and 3,000 hertz.

In order to merit an award, the average of the four speech frequency levels must be 35 decibels in each ear and the hearing loss in decibels is converted into percentage of impairment….

The Worker's Position

The worker participated via teleconference and was assisted by his spouse in making his presentation. Because the worker advised of his difficulties in hearing voices on the phone either directly or by speakerphone, the worker's spouse agreed to act as a translator on the worker's behalf by conveying the panel's statements or questions to the worker. The worker indicated during the hearing that he was satisfied with this method of facilitating his participation in the hearing process.

The worker described the nature and extent of his hearing loss to the panel, and specifically referred to the July 9, 2011 letter from a Saskatchewan-based audiologist who had tested the worker on behalf of the WCB. He indicated that the audiologist had accurately described his hearing loss and felt that her comments supported his position. The letter described a number of difficulties that would be associated with a moderately severe hearing loss, including difficulties with normal conversation, speech discrimination, answering to his name, the ability to hear alarms and warning signals, and in particular the effect of background noise.

In response to questions from the panel, the worker indicated that he has not had further testing done since he was tested in May 2011. Since that date, he has not been examined by or spoken with any other healthcare professional regarding his hearing loss or gotten any other opinions regarding the test results or the issue under consideration by the panel.

The worker disagreed with the comments made by the WCB ENT consultant, indicating that there was a system bias against his claim caused by the relationship between any consultant and the WCB. For this reason, he asked the panel to discount the WCB ENT consultant's opinion in favour of the Saskatchewan audiologist's opinion.

The employer's position:

The employer did not participate in the appeal.

Analysis:

The worker is seeking to have his PPD award based on audiogram results rather than the results from the cortical evoked responses testing (CER), which the WCB has chosen to use as the basis for a recent increase in his PPD award. The audiogram showed a greater loss of hearing than the CER and its use would result in a higher PPD award than what was granted to him when the CER was used.

For the worker to be successful in his appeal, the panel would have to find, on a balance of probabilities, that the audiogram testing is a more accurate reflection of the worker's hearing loss than CER testing. After careful consideration of the worker's presentation and the evidence that is on the file, the panel was unable to make this finding for the following reasons.

At the outset, the panel notes that the issue under appeal is quite narrow, and deals only with how to measure the worker's current hearing loss for the purposes of establishing a new PPD award. As noted in the background, the general facts are as follows:

• The worker has an accepted claim for noise-induced hearing loss.
• He has already been assessed twice for a PPD award. He was provided with an 8.4% award originally. His PPD award was later increased in 2000 to 10.8%. These tests were based on audiograms.
• In 2007, the worker advised the WCB of increased difficulties in hearing, which led to an audiogram being performed in 2007.
• The WCB, based on a review by its ENT consultant, indicated there were inconsistencies in the audiograms taken in 2003, 2005, and 2007, and wanted CER testing done in Saskatchewan, as it was a more accurate measure. The worker declined to participate in that testing, and as a result the WCB declined to reassess the worker's PPD, indicating that it was not supported by the currently available medical evidence. This decision was confirmed by an earlier Appeal Commission panel, in Decision 38/10.
• The worker eventually did have the CER testing done in Saskatchewan on May 16, 2011.

The panel notes that the WCB Policy indicates that calculation of hearing impairment will be averaged at four specific frequencies: 500, 1000, 2000, and 3000 hertz, and the medical information on the file suggests that this can be measured both with audiograms and CER testing.

Both tests were in fact performed on May 16, 2011, and the test results and the comments of the Saskatchewan based audiologist at the testing facility have played a significant role in our determination of this appeal.

The panel notes that a visual comparison of the May 16, 2011 audiogram and CER test suggests that there is a significant difference between the two; the audiogram shows greater hearing loss than the CER test results. The audiologist confirms these differences, in her letter of May 17, 2011. She states:

Cortical Evoked Responses:

Cortical testing was performed without knowledge of the audiometric results performed at this clinic. Threshold estimates were documented and then compared with the audiogram. Cortical responses were obtained at the four test frequencies of 500 Hz, 1kHz, 2kHz and 3kHz. Cortical results are generally observed within 10-15dB of the true behavioral thresholds.

Cortical results do not support the audiometric findings of today's audiogram at 500Hz, 1kHz and 2kHz in the left ear but do support the results for 3kHz. Cortical results do not support 500Hz, 1kHz and do agree with the behavioral findings for 2kHz and 3kHz for the right ear. At frequencies where the cortical did not support the results, the cortical was better than the voluntary response. [emphasis ours]

The panel notes that the testing undertaken in Saskatchewan was consistent with the four testing thresholds that are required under the Policy. As well, two different audiometric testing methods were used on the same day, affording the audiologist the opportunity to make a fair comparison of the tests and the test results. This is the specific issue in this appeal. In our view, the audiologist has noted the discrepancies in the two sets of results. She does note that the audiogram does have a voluntary component to the responses.

The panel agrees with the position taken, in general terms, by the WCB ENT consultant who states in his memo of October 20, 2007 that CER testing is more reliable for the specific purpose of establishing an impairment rating for hearing loss under the Policy. It measures hearing loss directly, without the direct and voluntary responses of the person being tested, which can distort the test results.

In our review of the audiologist's letter of July 9, 2011, we do not find any direct support for the worker's appeal regarding which test is better, or whether he is getting the right PPD amount. Rather, it is supportive of the worker's moderately severe hearing loss, it confirms the types of problems he will have on a daily basis, and discusses the types of hearing devices that might assist him. These issues, however, are not part of the narrow issue that the panel is considering today, and it remains open for the worker to continue those discussions with the WCB.

The panel therefore finds, on a balance of probabilities, that the worker's PPD award should be based on the CER testing, rather than on the audiogram results.

The worker's appeal is therefore denied.

Panel Members

L. Choy, Presiding Officer
A. Finkel, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kos

A. Finkel - Commissioner

Signed at Winnipeg this 22nd day of November, 2013