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CAOHC Newsletter: UPDATE

A Reviewer's Perspective of Case History Data
by Roger M. Angelelli, Ph.D.
CAOHC Course Director, Bethel Park, PA

The Amendment specifies that records of audiometric test results be maintained for the duration of employment of the affected employee and noise exposure measurement records be kept for two years.

In addition to the minimum record keeping requirements the obvious inclusion of employer name and location as well as employee number and department is recommended. Although the social security number is not required on the CHF most computerized reports will use the SSN as a key reference for the tested employee. In some instances (foreign workers) where no SSN is listed, the computer consultant generates a nine-digit number, e.g. 111-11-1111 to handle this situation. Occasionally the employee will not know or forget his/her SSN and, again, a delay occurs in processing if the COHC does not realize this omission or fails to obtain the SSN prior to sending the CHF’s to the professional reviewer.

The ear inspection using an otoscope is not required by the Hearing Conservation Amendment, however, it is recommended that prior to placing the earphones over the ears an otoscopic inspection take place to note the presence of an intact eardrum (tympanic membrane) as well as any unusual condition such as excessive cerumen which might influence the hearing threshold levels. Again, if no ear inspection is performed the reviewer must "assume" that the outer ear does not present any adverse influence on the obtained pure tone air conduction thresholds. A dangerous assumption.

The date of the last electroacoustic calibration of your audiometer needs to be completed along with make, model and serial number. If calibration records are not retained for verification of valid and reliable audiometric testing in the past, the credibility of your "effective" hearing conservation program could be at risk. It is not unusual for calibration questions to be asked in the often feared deposition. With regard to Y2K compliance of your microprocessor audiometer, it is essential that the appropriate EPROM (chip) be installed depending upon your model and serial number, however, there is no requirement that the audiometer needs to be re-calibrated electroacoustically. A verification of the accuracy of pure tone thresholds via a biological calibration would be sufficient.

Of course, if your audiometer is due for it’s annual electroacoustic calibration, it would be most appropriate to combine the installation of the necessary "chip" with calibration.

Has it been more than 14 hours since the worker’s most recent noise exposure? Although the actual noise exposure level is not required on the case history form, it is essential that information of noise levels be kept or filed with the audiometric test results. It was not OSHA’s intention to require that this information be entered on the actual audiogram or case history form. Again, the quiet period of 14 hours can be achieved with the use of hearing protectors as a substitute. OSHA concurred with testimony stating that hearing protectors may provide sufficient attenuation to prevent noise induced TTS from contaminating baseline audiograms. It is also important to consider non-occupational noise exposure with reference to the aforementioned question. Specifically the COHC should encourage the use of hearing protectors outside the workplace and inform employees of the importance of avoiding excessive noise exposure prior to any audiometric testing, baseline or annual.

(The COHC needs to make a comment on the CHF if the employee has or has not worn hearing protection prior to audiometric testing if less than 14 hours in noise exposure.)

Selection of a variety of types & styles of hearing protection devices (HPDs) for employees needs to be documented as evidence of availability. Information of the type of HPD worn, coupled with the noise exposure level and duration, would be useful to the professional reviewer in assessing the efficiency of hearing protection. Again, the selection of one or more type of plug or muff is often overlooked, and the usually false assumption is that no hearing protection is utilized. This type of omission can usually be traced to the COHC relinquishing his/her responsibility of actually completing the CHF.

The nuts and bolts of every effective hearing conservation program (HCP) is the accurate determination of establishing reliable pure tone air conduction thresholds for a variety of tones or test frequencies. OSHA has specified that the frequencies of .5KHz, 1KHz, 2KHz, 3KHz, 4KHz, and 6KHz be tested, however, most companies developed CHF’s to include 8KHz and, therefore, it is recommended that 8KHz be included. The information gleaned from the threshold at 8KHz helps the professional reviewer to support the existence of a mild, moderate, severe or profound hearing loss and its relationship to aging.

Each pure tone threshold must be legible, and, if it becomes necessary to cross out a previously obtained threshold for a revised one, the COHC should initial such a change. The lack of your initials beside a changed threshold may again raise a question during a deposition of the accuracy and integrity of the audiometric record. The air conduction thresholds not only provide the reviewer with information of the degree of hearing impairment, but the presence of a standard threshold shift is determined based upon the comparison of baseline thresholds at 2, 3, and 4KHz with current thresholds. Therefore, the COHC is ultimately charged with the critical task

of not only supplying complete responses to the many pertinent questions on the CHF, but to establish accurate pure tone thresholds which are reviewed and entered into a computer software that generates computer reports.

The generation of computer reports to the employer provides company officials with relevant information about the success or failure of their HCP. The COHC plays a major role in the hearing health of the workers in their care and maintaining accurate records is one of the most important aspects of this role.