Healthy News for Healthy Nation

A healthy ear emits soft sounds in response to the sounds that travel in. Detectable with sensitive microphones, these otoacoustic emissions help doctors test newborns’ hearing. A deaf ear doesn’t produce these echoes. (Credit: iStockphoto/Stacey Newman)

A healthy ear emits soft sounds in response to the sounds that travel in. Detectable with sensitive microphones, these otoacoustic emissions help doctors test newborns’ hearing. A deaf ear doesn’t produce these echoes.
New research involving the University of Michigan and Oregon Health and Science University shows that, contrary to the current scientific thought, the emissions don’t leave the ear the same way they entered. The findings give new insight into a phenomenon that researchers study to better understand hearing loss, and they reinforce a previous controversial study that came to a similar conclusion.

“The former wisdom on how otoacoustic emissions left the ear was that there was a backward-traveling wave going along the structure of the cochlea in the same way as the forward-traveling sound wave,” said Karl Grosh, a professor in the U-M departments of Mechanical Engineering and Biomedical Engineering and an author of the paper. “These measurements show that is not the case.”

Grosh said the next step is to develop tools to find out where hearing damage is occurring. “If we want to try to infer from the emission what’s wrong with the ear, we have to understand how the emission is produced,” Grosh said.

The experiment, performed at the Oregon Health and Science University in associate professor Tianying Ren’s lab, showed that the sound waves coming out travel through the fluid of the inner ear, rather than rippling along the basilar membrane of the cochlea.

The cochlea, located deep in the ear, is shaped like a snail. The basilar membrane essentially cuts the inner channel of the cochlea diametrically in half into two chambers. Both chambers are filled with liquid.

Sound waves going into the ear undulate along the basilar membrane through the cochlea and eventually excite the organ of Corti, which senses and sends the sound signals to the brain through the auditory nerve.

Sounds coming out of the ear, according to results from this experiment, likely travel through the fluid on either side of the basilar membrane.

For this experiment, the researchers used laser interferometers, which detect waves, to measure vibrations of the basilar membrane in response to sound at two locations in the cochlea of gerbils. They detected evidence of sound waves traveling forward on the membrane, but they found no evidence of backward-traveling waves.

“Our new method can detect vibrations of less than a picometer, 1,000 times smaller than the diameter of an atom. The new data demonstrate that there is no detectable backward-traveling wave at physiological sound levels across a wide frequency range,” said Ren, principal investigator of this project. “This knowledge will change scientists’ fundamental thinking on how waves propagate inside the cochlea, or how the cochlea processes sounds.”

A paper  on the research entitled “Reverse wave propagation in the cochlea” was recently published in the Proceedings of the National Academy of Sciences.

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Researchers includng Drs. Khashayar Sakhaee (left), chief of mineral metabolism, and Dion Graybeal have discovered that a drug commonly prescribed to treat seizures and migraine headaches can increase the propensity of calcium phosphate kidney stones. (Image courtesy of UT Southwestern Medical Center)

Topiramate (Topamax), a drug commonly prescribed to treat seizures and migraine headaches, can increase the propensity of calcium phosphate kidney stones, researchers at UT Southwestern Medical Center have found.
A study — the largest cross-sectional examination of how the long-term use of topiramate affects kidney-stone formation — appears in the October issue of the American Journal of Kidney Diseases.

Several case reports have described an association between topiramate and the development of kidney stones, but this complication had not been well recognized and physicians have not informed patients about the risk, the UT Southwestern researchers said. More important, the mechanism of stone formation was largely unknown previously.

“The wide-spread and escalating use of topiramate emphasizes the importance of considering the long-term impact of this drug on kidney-stone formation,” said Dr. Khashayar Sakhaee, senior author of the study and chief of mineral metabolism at UT Southwestern.

More than 29 million Americans suffer from migraines, with women being affected three times more often than men, according to the National Headache Foundation.

“Topiramate is probably one of the most commonly prescribed and most effective neurological medications right now,” said Dr. Dion Graybeal, assistant professor of neurology and an author of the study.

Dr. Graybeal and other researchers at UT Southwestern say the next step is to develop a way to block the development of kidney stones for users.

The study comprised two phases. Thirty-two individuals already being treated with topiramate and 50 normal volunteers were enrolled in a cross-sectional study in which their blood and urine were tested for kidney-stone risk. A short-term study also was conducted in seven individuals to assess stone risk before and three months after taking topiramate. All patients were evaluated at UT Southwestern’s General Clinical Research Center.

Researchers found that taking topiramate on a long-term basis, or for about one year, caused systemic metabolic acidosis — a buildup of excessive acid in the blood — as a result of the inability of the kidney to excrete acid. Topiramate use also increased the urine pH and lowered urine citrate, an important inhibitor of kidney-stone formation.

“These changes increase the propensity to form calcium phosphate stones,” Dr. Sakhaee said.

In the short-term study, urinary calcium and oxalate — a chemical compound that binds strongly with calcium and is found in most calcium stones — did not significantly change in people taking topiramate.

Kidney stones are solid deposits that form in the kidneys from substances excreted in the urine. When waste materials in urine do not dissolve completely, microscopic particles begin to form and, over time, grow into kidney stones.

Before this study, the rate of kidney-stone formation with topiramate was reported as 1.5 percent. The low incidence rate may be an underestimation due to the short length of observation and the lack of ongoing kidney-stone surveillance and data collection for this drug, said Dr. Sakhaee, holder of the BeautiControl Cosmetics Inc. Professorship in Mineral Metabolism and Osteoporosis.

“There is a legitimate concern for the occurrence of kidney stones with long-term topiramate treatment,” said Dr. Sakhaee said. “Studies are needed to explore optimal measures to prevent kidney-stone formation with topiramate use.”

Other UT Southwestern researchers contributing to the study were Dr. Orson Moe, director of the Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, Dr. Naim Maalouf, assistant professor of internal medicine and Dr. Brian J. Welch, a postdoctoral fellow in internal medicine.

The research was supported by the National Institutes of Health.

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Plastic surgeon Dr. Jeffrey Janis marks a site that, using the anti-wrinkle drug Botox, pinpointed a muscle later removed to help relieve Sharon Schafer Bennett’s severe migraines. (Credit: Image courtesy of UT Southwestern Medical Center)

Five years ago, Sharon Schafer Bennett suffered from migraines so severe that the headaches disrupted her life, kept her from seeking a job and interfered with participation in her children’s daily activities.
Now, thanks to an innovative surgical technique performed by a UT Southwestern Medical Center plastic surgeon who helped pioneer the procedure, the frequency and intensity of Mrs. Bennett’s migraines have diminished dramatically — from two to three per week to an occasional one every few months.

The technique — performed by a handful of plastic surgeons in the U.S. — includes using the anti-wrinkle drug Botox to pinpoint which of several specific muscles in the forehead, back of the head or temple areas may be serving as “trigger points” to compress, irritate or entrap nerves that could be causing the migraine. Because Botox temporarily paralyzes muscles, usually for about three months, it can be used as a “litmus test” or “marker” to see if headaches go away or become less intense while the Botox’s effects last, said Dr. Jeffrey Janis, assistant professor of plastic surgery.

If the Botox is successful in preventing migraines or lessening their severity, then surgery to remove the targeted muscle is likely to accomplish the same result, but on a more long-term and possibly permanent basis, he said.

For Mrs. Bennett, the surgery proved to be life-altering.

“I can’t even begin to tell you what a change this has made in my life,” said Mrs. Bennett, 45, a Houston-area resident. “For the first time in years, I can live like a normal human being and do all the normal ‘mom’ and ‘wife’ things that the migraines physically prevented me from doing. My family thinks it’s great because they don’t have to put their lives on hold numerous times a week because of my migraines. I’m also going back to school to get a second degree, something I could never have considered before.”

Dr. Janis said: “Many neurologists are using Botox to treat migraines, but they are making the injections in a ‘headband-like’ circle around the forehead, temple and skull. They are not looking at finding the specific location of the headache’s trigger point. While patients may get temporary relief, after the Botox wears off they will have to go back and get more injections or continue medications for migraines.

“It’s like a math equation. I will inject the Botox into one trigger point at a time and leave the others alone. The Botox is used as a diagnostic test to determine what trigger point is causing the problem. If patients get a benefit from the Botox, they likely will get a benefit from the surgery. If there’s no benefit from the Botox, then there won’t be a benefit from the surgery.”

Dr. Janis began collaborating more than five years ago with Dr. Bahman Guyuron, a plastic surgeon at Case Western Reserve University and the first to explore using surgery to relieve migraines, following the revelation by several of his patients that their migraines had disappeared after they had cosmetic brow lifts. Dr. Janis has assisted his colleague by performing anatomical studies on cadavers to explore the nerves and pathways that might cause migraines. Together they have identified four specific trigger points and developed a treatment algorithm that includes using Botox prior to deciding whether to perform surgery.

During the past several years, numerous peer-reviewed articles have been published in Plastic & Reconstructive Surgery detailing their research efforts and the researchers have presented the technique at professional meetings of plastic surgeons.

Approximately 28 million Americans, 75 percent of those women, suffer from migraines, according to the National Institutes of Health. For employers, that translates into an estimated 157 million lost workdays annually.

“A migraine is something you can’t explain to someone who hasn’t had one,” said Mrs. Bennett, who began suffering monthly migraines as a teenager. As she grew older, the headaches become more frequent and unpredictable. “They were messing up my life. I couldn’t make any commitments or plan activities for my kids. This surgery has made a huge difference in my life. It’s awesome.”

Dr. Janis only sees patients who have been diagnosed with recurring migraines by a neurologist and have tried other treatments that have failed.

“Plastic surgeons are not in the business of diagnosing and treating headaches,” he said. “This is a novel method of treatment that is proving to be effective and potentially more long lasting than other things used before. But it is still in its infancy.”

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Nearly 30 million Americans suffer from migraines. (Credit: iStockphoto/Guillermo Perales Gonzalez)

Migraines are more than a bad headache. As nearly 30 million Americans can attest, the throbbing pain of a migraine can be debilitating, lasting from a few hours to several days. The condition can be aggravated by light, sounds, odors, exercise, even routine physical activities. Nausea, with or without vomiting, may occur.

Fortunately, treatment helps most people who have migraines.

Doctors may recommend preventive medications for patients who have two or more debilitating episodes a month. Typically the medication is taken at regular intervals, often daily. Antidepressants, anti-seizure medications and cardiovascular drugs may help prevent migraines.

Infrequently, nonprescription nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin, others) or naproxen sodium (Aleve, others) may help. Injections of botulinum toxin type A (Botox) is an alternative for people who can’t take or don’t respond well to preventive medications. However, this use of Botox for migraine prevention is not approved by the Food and Drug Administration.

Pain relief drugs for migraines should be taken as soon as symptoms begin. Mild migraines may respond to NSAIDs or aspirin. A moderate migraine may respond to a nonprescription combination of a drug containing acetaminophen, aspirin and caffeine. Other drug categories used to treat pain include triptans, which mimic the action of the brain chemical serotonin; anti-nausea and related drugs; and ergots, which were used for decades before the more recent introduction of triptans.

Some patients find relief from alternative therapies. The National Institutes of Health has concluded that acupuncture may help control headaches. A study in the journal Headache showed that a combination of yoga, breathing exercises and relaxation techniques reduces migraine frequency and pain.

Some find benefit in herbal remedies, such as butterbur, which appears to be safe if taken for a short period to prevent migraines. In addition, the supplement coenzyme Q10 appears to reduce migraine frequency for some. Patients who consider alternative therapies should consult their physician about the pros and cons and to prevent any drug interactions.

The September issue of Mayo Clinic Health Letter provides more information on treatments to prevent migraines and stop the pain.

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