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JOURNAL WATCH: Evidence Lacking to Guide Treatment for Sudden Hearing Loss

CHICAGO – Although steroids are the most widely used treatment for sudden hearing loss, little scientific evidence supports their use or that of any other therapies for this condition, according to a systematic review and meta-analysis both published in the June issue of Archives of Otolaryngology–Head & Neck Surgery, one of the JAMA/Archives journals.

Sudden sensorineural hearing loss is acute hearing impairment involving loss of at least 30 decibels of hearing over at least three test frequencies occurring within three days, according to background information in the article. The condition affects about five to 20 of every 100,000 individuals yearly. Treatment varies widely and includes antiviral medications, vitamins, minerals, herbs, hyperbaric oxygen and agents that dilute the blood. “In addition, some otolaryngologists choose not to treat sudden sensorineural hearing loss at all, citing spontaneous recovery rates of 32 percent to 70 percent,” the authors write. “However, the most common approach to treatment of sudden sensorineural hearing loss in North America is with systemic steroids, which has been deemed by some authors to be the gold standard of treatment.”

Anne Elizabeth Conlin, B.A. & Sc., M.D., of the University of Ottawa, Ontario, and Lorne S. Parnes, M.D., F.R.C.S.C., of the University of Western Ontario, London, Canada, searched for all randomized clinical trials evaluating treatments for sudden hearing loss published between 1966 and 2006.

For the systematic review, 21 trials were identified and evaluated, all of which used measures from hearing tests to define treatment outcomes. “Only two studies used identical criteria to define sudden sensorineural hearing loss,” the authors write. “The method of randomization was described in two studies. Validity scores ranged from two to eight (of nine). Positive results were reported favoring systemic steroids, intratympanic [inside the inner ear] steroids, batroxobin, magnesium, vitamin E and hyperbaric oxygen, although there were serious limitations in each study with a positive finding.”

This includes the article cited as the landmark study for the use of steroids, which was not described as a randomized trial and therefore may have produced exaggerated treatment effects, the authors note. The authors suggest that this study also used inconsistent doses of steroids and did not measure outcomes at the same time for all participants. “The study therefore does not inform the otolaryngologist of what dose of steroids to use, nor at what time after treatment to expect improvement,” the authors write.

“To our knowledge, no valid randomized controlled trial exists to determine effective treatment of sudden sensorineural hearing loss,” they conclude. “Systemic steroids cannot be considered the gold standard of treatment of sudden sensorineural hearing loss, given the severe limitations of the landmark study supporting their use.”

For the meta-analysis, data from the same trials were combined when they covered the same therapies. Five trials were eligible for the analysis. “Pooling of data from two randomized clinical trials that compared steroids with placebo showed no difference between treatment groups,” the authors write. “No difference existed between patients treated with antiviral plus steroid therapy vs. placebo plus steroid therapy. Finally, there was no difference between subjects treated with steroids vs. subjects treated with any other active treatment.”

Treating sudden hearing loss is difficult because its cause is often unknown, the authors note. However, it is still important to identify the therapy that most benefits the patient. “At present, sudden sensorineural hearing loss remains a medical emergency without a scientific understanding of its cause or a rational approach to its treatment,” they conclude.

Journal Watch: Impact of Tinnitus on Quality of Life

For the over 50 million Americans with tinnitus, it is no surprise that their constant ear or head noises has the ability to affect their quality of life. Now researchers from the University of Wisconsin and Arizona State University have documented clear associations between tinnitus and reduced quality of life. The five-year study, published in the March issue of the Journal of the American Academy of Audiology, included almost 2800 subjects with an average age of sixty-nine. The study’s authors concluded that quality of life is diminished in those with tinnitus, and the effect increases with increasing severity of the tinnitus. It is expected that the number of individuals who will be negatively affected by tinnitus will increase along with improvements in longevity. The authors of the study suggest “additional efforts to identify effective prevention, diagnosis, and treatment, to increase the quality of life experienced by older adults”.

Diabetes and Hearing Loss?

Diabetes Health is an inspiring magazine dedicated to helping those with diabetes lead healthier lives. The most recent issue (April/ May 2007) features an article contributed by yours truly. Here are some highlights. Research studies have shown that people with type 1 and type 2 diabetes experience more hearing loss than their non-diabetic peers. This is attributed to changes in the small blood vessels responsible for transporting nutrients to the inner ear. As a result of compromised blood flow, atrophy and death of the inner ear’s sensory hair cells occurs leading to hearing loss. The article concludes by offering key habits every person managing diabetes should incorporate into their preventive healthcare routine, including: annual hearing evaluations by a licensed hearing healthcare provider, thorough ear examinations by a physician, care in noisy occupational and recreational environments and simply being mindful and appreciate the wonderful sense of hearing that connects us to our world.

Also, if you or someone you love is managing diabetes I suggest taking a few moments to visit Diabetes Mine. This blog authored by Amy Tenderich offers daily updates on what's going on in the world of diabetes. Diabetes Mine is a valuable resource for anyone touched by this rapidly growing health issue.

Parents, Take Control of Noisy Toys

The December holiday season is long gone, but the war zone of a playroom in my house serves as a reminder of all the gifts the grandparents so happily shared with our children. During the end of last year, the organization Deafness Research UK released the results of a study by Dr. Brad Backus of UCL’s Ear Institute in London. The study investigated the potential hazards that certain toys might pose to children. According to the researchers, “Children's toys clearly have the potential to do harm to their hearing so it's important that people are aware of the dangers and what to do about them. With most toys, your child will only damage their hearing if they use them too often and for too long a duration, or if they stick them in their ear.”

This is not new information, but it re-educates parents at a critical time of the year when they are filling their carts with gifts. I’ve always questioned the possibility of dangerous sound levels from several of my sons’ favorite toys. My wife and I have also spent time (on a regular basis) reminding them to not put certain louder toys close to their ears. We’ve even gone as far as taking certain "acoustic offenders" away for concern of potential harm. But it wasn’t until recently I decided to pull out a simple sound level meter from Radio Shack to see what some of the toys were capable of.

One of the favorite toys in the house is a Sesame Street toy. When buttons are pushed, a character pops up and a quick song is played from a small speaker. At a distance of approximately 12 inches (the distance of “normal” play for an infant), a level of 86 dBA was noted on repeated measures. A distance of 1 inch (holding the toy directly near the ear), a level of 103 dBA was recorded.

Another toy I decided to measure is a battery-powered figure eight race track from the movie “Cars”. At a distance of 12 inches, the sound level was on the order of 84 dBA. Closer, 88 dBA. Any time a sound exposure reaches a level of 85 dBA, there is potential for hearing damage. Keep in mind, a level of 85 dBA is considered safe for a duration of time longer than most children will play with the offending toys. But, a level of 103 dBA has the potential to cause hearing damage in a very short period of time. These measures were not performed in a laboratory, or with a highly calibrated sound level meter but this small experiment did serve to illustrate the potential of certain toys found in most toy rooms.

ASHA, the American Speech-Language and Hearing Association, offers the following guidelines: Prior to purchasing a new toy, parents should listen to the toy. If it sounds too loud, it should not be purchased. Toys already at home should also be examined. Batteries can be removed or toys discarded if they are too noisy and pose a potential danger to hearing.

Effectiveness of Cognitive Behavioral Therapy for Tinnitus

Founded in 1993, the Cochrane Collaboration is a UK-based not-for-profit organization that is dedicated to making healthcare information readily available to the public. The organization recently released a meta-analysis of six randomized controlled studies that investigated the use of cognitive behavioral therapy for those with tinnitus. Cognitive behavioral therapy, or CBT, “uses relaxation, cognitive restructuring of thoughts and exposure to exacerbating situations in order to provide habituation”. CBT plays a role in several current tinnitus treatments. The Cochrane analysis revealed no significant difference in the subjective loudness of patients’ tinnitus, or in the associated symptoms of depression. However, the reviewers did uncover a significant improvement in quality of life (i.e. decrease of global tinnitus severity). The authors of the study concluded, “cognitive behavioral therapy has an effect on the qualitative aspects of tinnitus and contributes positively to the management of tinnitus”.

For more information on this study, visit The Cochrane Collaboration site.