Although originally written in 2003 for publishment in the Tennessee Trial Lawyer for the Tennessee Trial Lawyer Association, hearing loss claims continue to be an area of active litigation in Tennessee. Following the original text I have noted some of the cases that have come out in Tennessee dealing with hearing loss and tinnitus.
Hearing a Good Case – Tips on Evaluating and Prosecuting a Noise-Induced Hearing Loss Workers’ Compensation Case
Hearing loss may not sound like a gripping workers’ compensation injury, but a closer look at the prevalence of noise induced hearing loss should make a trial lawyer stop and listen. It is estimated that 10 million Americans have noise induced hearing loss and that number will only grow considering an estimated 25% of the American workforce is habitually exposed to potentially hazardous sounds.1 This irreversible ailment is often accompanied by a menacing sidekick, tinnitus, best described as ringing in the ears. One of the inherent difficulties of this injury, legally, is that it creeps up on the worker until finally his wife is nagging him about ignoring her. Occupational noise induced hearing loss workers’ compensation claims can be successfully pursued with proper evaluation and prosecution. This article will share some tips on evaluating and prosecuting these cases.
What Is Noise-Induced Hearing Loss?
To be able to evaluate a case, it is imperative that you understand noise and hearing loss, or specifically, noise-induced hearing loss (NIHL). Noise is annoying or unwanted sound usually measured by a sound-level meter in decibels.2 Meters or dosimeters can measure peak and continuous exposures to gain accurate information on what level of noise a worker is exposed to and for what periods of time. Noise at high levels (typically 85 dB or more) over time can lead to NIHL.
A person hears when sound travels through the ear and is converted into electrical impulses that are conducted via nerve cells to the brain. NIHL is caused when the receptor level of the cochlea of the inner ear is damaged.3 Specifically, loud sound damages the inner hair cells and outer hair cells of the organ of Corti making it more difficult for those cells to work properly. Those cells are responsible for transforming sound energy into electrical impulses and different length cells are triggered by different frequencies of sound. When the cells are damaged, it takes more sound energy or louder sound to trigger their response and hence you find a hearing loss at the frequency level that correlates with the certain cells that have been damaged.
Hearing loss is determined through clinical diagnosis, including a hearing test or audiogram. The audiogram charts the decibel level loss at varying frequency levels. Frequencies tested range from 500 Hz to 8000 Hz. The worker will also have a speech discrimination test where the tester will read a series of words to the workers to determine recognition. This test will show at what decibel level words must be spoken for the worker to hear X% of the words. In a basic sense, the speech discrimination test is akin to seeing how loud you have to turn up the television to hear and understand what is being said on screen.
Hearing loss in the occupational setting can occur over time or as a result of sudden trauma. Occupational NIHL, as opposed to occupational acoustic trauma, is a slowly developing hearing loss over a long period (several years) as the result of exposure to continuous or intermittent loud noise. The diagnosis of NIHL is made clinically by a physician and should include a study of the noise exposure history.
Occupational acoustic trauma is a sudden change in hearing as a result of a single exposure to a sudden burst of sound, such as an explosive blast. This injury is similar to any other accidental injury for workers’ compensation purposes in terms of causation, notice, and statute of limitations. This article will focus on occupational NIHL, but the same considerations of impairment ratings and disability can be applied to acoustic trauma cases.
The worker with NIHL commonly has difficulty hearing and understanding ordinary speech and higher pitched sounds, such as a woman’s voice or a cell phone, especially in the presence of background noise. The audiogram of a “classic” noise induced hearing loss typically shows a symmetrical hearing pattern that drops off at 3 kHz with a notch at 4 kHz and then has a slight improvement at 8 kHz.4 The notch is usually due to impulsive noises like rifle fire. The notch is an indication of a sharp drop of hearing ability at the 4 kHz level and it is caused, most likely, because that area of the ear is most sensitive to noise.
The noise notch, which though typically is at 4 kHz, can be from 3 to 6 kHz, occurs for several reasons. It occurs because the ear has greater sensitivity to frequencies between 1 and 5 kHz, the receptors below 2 kHz are protected somewhat by the acoustic reflex below 2 kHz, intermittent noise most protective to low frequencies and damaging to higher frequencies, and the outer hair cell at the base of the cochlea where the notch frequencies are detected are especially susceptible to oxidative stress.5
As years of exposure to noise mount, the notch is often lost and hearing degrades at all levels, but the worst is still usually in the higher frequencies.6 The following chart7 shows the progression of a NIHL pattern, as it would be seen in an audiogram. The principal characteristics of occupational NIHL are as follows:
- It is always sensorineaural affecting the hair cells in the inner ear.
- It is almost always bilateral. Audio-metric patterns are usually similar bilaterally.
- It almost never produces a profound hearing loss. Usually, low-frequency limits are about 40 dB and high-frequency limits about 75 dB.
- Once the exposure to noise is discontinued, there is no significant further progression of hearing loss as a result of the noise exposure.
- Previously noise-induced hearing loss does not make the ear more sensitive to future noise-exposure. As the hearing threshold increases, the rate of loss decreases.
- The earliest damage to the inner ears reflects a loss at 3,000, 4,000, and 6,000 Hz. There is always far more loss at 3,000, 4,000, and 6,000 Hz than at 500, 1000, and 2,000 Hz. The greatest loss usually occurs at 4,000 Hz. The higher and lower frequencies take longer to be affected than the 3,000 to 6,000 Hz ranges.
- Given stable exposure conditions, losses at 3,000, 4,000 and 6,000 Hz will usually reach a maximal limit in about 10 to 15 years.
- Continuous noise exposure over the years is more damaging than interrupted exposure to noise, which permits the ear to have a rest period.8
If the audiometric pattern is asymmetrical (the left and right ear patterns do not match each other) then the hearing loss may not be occupationally noise-induced. Asymmetries greater than about 15 dB suggest other etiology or asymmetric noise exposures, most frequently being rifle or shotgun exposure. This is referred to as “shooter’s ear” and must be carefully screened with potential clients, though it can be easily spotted when looking at an audiogram because one ear is typically far worse than the other. If the worker is right handed, his left ear will be closer to the blast from the barrel thus producing the asymmetric pattern. However, if the worker is, for example, an OTR truck driver and has years of exposure driving with the window down, than this can also produce an asymmetric pattern.
As mentioned earlier, workers afflicted with NIHL are often bothered by another condition called tinnitus. A ringing, crackling, or sizzling sensation or noise in the ears typifies this subjective condition. Tinnitus is often most bothersome when the worker is in a quiet room without background noise to drown out the distraction.
The worker that contacts a lawyer regarding a hearing loss claim typically discovers the injury in one of several ways. Often his employer does OSHA testing with baseline shifts or regular employment physicals that note a change in hearing. The worker may begin to notice difficulty hearing and understanding speech and someone that has had a workers’ compensation claim for hearing loss tells him to get it checked out.
If a potential client has seen a physician or audiologist who performed an audiometric evaluation, then I suggest that the worker gather all his records before meeting with me. This information, along with a detailed history, will provide the information needed to decide whether a case for occupational NIHL is worth pursuing. If the worker has not been tested, I suggest that the worker see an otolaryngologist and have an evaluation performed prior to our meeting.
When you meet with the potential client, the review should begin with the audiometric evaluation. Review the chart for symmetry and pattern of hearing loss. Does it show a NIHL or is it consistent with other causes such as disease factors or “shooter’s ear?” A congenital or medical pattern typically shows losses that are across the board uniformly. Ideally, the worker brings a history of audiometric tests performed over a number of years so that you can see if the loss was gradual or sudden. Review the speech discrimination results to see what kind of recognition problems that worker may have and if they are consistent with the audiogram.
Next, determine the medical impairment associated with the hearing loss. The great thing about hearing impairments is once you have the audiometric results, you can calculate the exact impairment rating without contacting a physician. The AMA Guides to the Evaluation of Permanent Impairment, 5th Edition (“AMA Guides”) dictate the calculation of the impairment rating. However, you must be certain that the client performed the hearing tests as instructed and is not classified as having “functional hearing loss.” You will quickly see that the impairments are skewed toward the conservative side. To calculate the medical impairment rating, you must add the hearing levels at 500, 1000, 2000, and 3000 Hz for each ear separately (remember that NIHL most profoundly affects frequencies at 3000 Hz and above). Due to the inherent bias of the AMA Guides, workers often have moderate hearing loss in the high frequencies, but can have no impairment rating. With those results, consult Table 11-2 on page 248 to determine the binaural hearing impairment and Table 113 should be consulted to deduce the whole body impairment.
Additionally, the AMA Guides allocate up to 5% for tinnitus in the presence of measurable hearing loss if the tinnitus impacts the ability to perform activities of daily living. The AMA Guides do not specifically mention whether this impairment is to the body as a whole or if it should be added to the binaural impairment, but in the examples listed it is shown to be added to the binaural hearing impairment rating before conversion to a whole body impairment. However, as noted below, the Courts have not uniformly held tinnitus to be part of the binaural, scheduled hearing impairment and have found that it is a non-scheduled, whole body impairment.
If the audiometric testing shows a pattern that is not indicative of NIHL or there is no impairment rating, then your evaluation should stop at this point. If the pattern is indicative of a NIHL and there is an impairment rating, continue by getting a history. There are three factors to consider when determining the etiology of a NIHL for an individual and they are important in evaluating a possible claim. Those factors are:
- Intensity of noise exposure;
- Duration of noise exposure;
- Individual sensitivity.
For factors of intensity and duration of noise exposure, you will want to have the worker list all exposures to noise in the workplace and elsewhere. Does the client have dosimeter readings or OSHA violation reports from his workplace? These can make or break a borderline causation case. Does the worker do a lot of woodworking at home without hearing protection? If the majority of noise exposure comes from work, then the minimal affects of non-occupational exposure can be dealt with.
Individual sensitivity simply stated is the principle that some ears are more easily damaged by noise than are others. This is difficult to determine, but some questions about family history can be helpful. For instance, did the worker’s father and grandfather suffer from hearing loss and work around loud noises all their lives? Alternatively, did the worker’s mother have hearing loss without significant noise exposures? You should also determine if the worker has any conditions that might cause or accelerate problems with hearing such as high blood pressure, diabetes, or smoking. Additionally, certain ototoxic drugs, such as aminoglycosidic antibiotics, platinum-derivative anti-tumor agents, loop diuretics, and salicyclates, can cause hearing loss alone and can combine with noise to produce more profound damage to the ears than each separately.9
There are frequently issues of notice and statute of limitations in gradually occurring workers’ compensation claims. When did the worker become informed of the work-related hearing loss? As in all other gradual or repetitive injuries, the worker must give notice within 30 days of being informed of a disability arising out of work. If the employer is performing the hearing test, then notice is less of an issue. If the worker presents with a suspicion, but no medical finding, get an evaluation, then give notice when it has been medically confirmed. Remember, every day there is exposure to noise at work is another day of injury. Apply the current law for repetitive and gradual injuries regarding notice and statute of limitations to NIHL cases.
NIHL cases, more than other injuries, involve a type of employee that brings notice and statute of limitation issues front and center: the retiree. Retiree NIHL cases present a myriad of issues that could fill an entire article separately, but primarily each case should be dealt with individually because the fact issues, especially notice, statute of limitations, and impairment, will rise and fall on the specific facts for that employee. Did the retiree know of the work-related hearing loss when he left? If he did, did the employer do anything to toll the statute? Also, it is difficult to prosecute the long-term retiree claim if there are no hearing tests performed around the time of retirement to know what the medical impairment was at the time of retirement. Keep in mind that NIHL will typically plateau after exposure ceases so if a retiree presents with current results that are significantly different than when he left employment, then it will be difficult to prove that subsequent loss arose out of the employment.
Often, the worker has sought legal representation after being informed of a threshold shift from his employer. In this situation, chances are the worker will be best represented if you obtain an IME from an otolaryngologist. Send the doctor all past records so the doctor can see the progression of the hearing loss. If there are any dosimeter readings, provide them as well. Try to research your client’s job and provide any literature on that occupation and NIHL to the physician. For instance, research OSHA standards and studies for that occupation. The worker should give the most detailed noise history possible, listing all causes of noise and durations of exposure, including occupational and non-occupational. The worker needs to describe his use of hearing protection, again, both occupational and non-occupational. If the worker suffers from tinnitus, he should go into detail with the physician regarding the difficulties caused by the tinnitus. Since tinnitus is a subjective complaint, the impairment rating given will depend greatly on the impact on the worker’s life as described by the worker.
When taking medical expert proof, either during cross or direct-examination, it is important, as always, to get causation within a reasonable degree of medical certainty. The defense expert will likely deny causation if the “classic” pattern of NIHL is not present or blame the etiology of NIHL on some other noise exposure. Remember, the “classic” pattern depends on individual sensitivity and is not always present after the initial stages of NIHL. The “classic” pattern may not be present if there is a mix of causes for the hearing loss and your expert may be willing to testify that noise from work, more probably than not, caused or contributed to the overall loss. Be prepared with noise studies and hypotheticals based on the worker’s testimony of occupational noise exposure and non-occupational noise exposure.
It can be very effective to question the medical expert regarding the inherent bias of the AMA Guides. I find it helpful to have the expert describe NIHL and the frequencies most affected and then have the expert testify as to how the impairment ratings are calculated pointing out that the Guides do not consider the frequencies most affected by NIHL. Also, the Guides do not take into account speech discrimination, which is often a good indicator of a worker’s ability to actually hear and understand speech.
Lastly, on impairment ratings, have the expert delineate the medical impairment ratings for hearing loss and tinnitus separately. Have the expert convert the hearing loss impairment to the body as a whole separately from the tinnitus. This way, as discussed below, the Trial Court can use the impairments it believes comport with the law.
In trying a NIHL workers’ compensation case, the strategies are similar to any other gradual or repetitive injury case. Due to the bias of the guides, which should have been covered in detail in your expert proof, it is important for the worker and any witnesses to testify to trouble with “real world” hearing loss and disability, especially if there is a low medical impairment rating. Have the worker detail problems with understanding speech and hearing high-pitched noises, especially those that might be present in the workplace.
If tinnitus is present, argue that it is a whole body injury case. Until recently, the AMA Guides was the only indication as to how this injury is to be treated in conjunction with hearing loss. However, last year a Workers’ Compensation Special Panel decided Sills v. Humboldt Nursing Home, Inc., 2002 WL 927434 (Tenn. Workers Comp. Panel) upholding a Trial Court’s finding that tinnitus was a non-scheduled injury requiring conversion of hearing loss to a whole body disability. Id. The worker in Sills had a total loss of hearing in the right ear with a lot of dizziness. In that case the otolaryngologist gave 16% for hearing loss or 6% whole body and another 5% whole body for tinnitus. The Panel stated “a disability resulting from an injury to a scheduled member may be apportioned to the body as a whole if the injury extends beyond the scheduled member.” Id. at *3 (citing Wells v. Sentry Ins. Co., 834 S.W.2d 935, 937 (Tenn. 1992). “When there is evidence that a claimant has suffered not only a loss of hearing, but also some additionally injury, such as dizziness, nausea, or headaches, there is a basis for an award for permanent partial disability to the body as a whole.” Id. (citing F. Perlamn and Co. v. Ellis, 410 S.W.2d 166 (Tenn. 1966). The Court found the additional injury of tinnitus is separate and apart from the complete loss of hearing in one ear and thus a correct whole body injury.
4 Brenda L. Lansbury-Martin et al., Otolaryngology Head & Neck Surgery: Chapter 162 “Noise-Induced Hearing Loss” 3153.
- Id. at 3155.
- 2 Robert A. Dobie, Head & Neck Surgery, Chapter 147 “Noise-Induced Hearing Loss” 1883-4 (Karen H. Calhoun et al eds., 3rd ed. 2001)
- Id. at 1883-47 Id. at 18848 8 Id. at 18889 4 Brenda L. Lonsbury-Martin et al., Otolaryngology Head & Neck Surgery: Chapter 162 “Noise-Induced Hearing Loss” 3166 (Charles W. Cummings et al eds., 3rd ed. 1998)
Hearing Loss Cases in Tennessee:
Blair v. Inland Container Corp.
Ferguson v. Kirk
Smith v. Georgia Pacific Corp.
Woods v. Lockheed Martin Energy Systems, Inc.
For further information on Noise Induced Hearing Loss and workers compensation in the State of Tennessee, please visit our us at our website or contact us by phone at 865-584-1211.