The Hearing Professionals

The risk of falling rises threefold even with the mildest hearing loss, according to a study. For moderate deafness, the chance of an accident doubles again – probably because such people have a poorer sense of their surroundings and are more likely to trip.

The researches also suggested that the brain may not be able to focus on balance and gait when it is struggling with hearing.

The study at Johns Hopkins University School of Medicine, Baltimore, was based on the health records of more than 20,000 patients aged from 40 to 69.

Dr. Frank Lin at Johns Hopkins, and his colleague Luigi Ferrucci of the National Institution on Aging, used data from the 2001 to 2004 cycles of the National Health and Nutrition Examination Survey.

The ongoing survey has gathered health data from thousands of Americans since 1971.

During those years, 2,017 people aged 40 to 69 had their hearing tested and answered questions about whether they had fallen over the past year.

Researchers also collected personal information including age, sex and race and tested participants’ vestibular function, a measure of how well they kept their balance.

The findings show that people with a 25-decibel hearing loss – classified as mild – were nearly three times more likely to have a history of falling. Every additional 10-decibels of hearing loss increased the chances of falling by 1.4 fold, says a report in the Archives of Internal Medicine journal.

A further 20-decibel hearing loss over the “mild” classification would push up the risk by threefold again.

Explanation: Dr. Lin, a hearing specialist and epidemiologist, says people can’t hear well may not have good awareness of their overall environment, making tripping more likely.

This finding still held true, even when researchers accounted for other factors linked with falling, including age, sex, race, cardiovascular disease and vestibular function.

Even excluding patients with more moderate to severe hearing loss from the analysis didn’t change the results.

He said another reason hearing loss might increase the risk of falls is cognitive load, in which the brain is overwhelmed with demands on its limited resources.

“Gait and balance are things most people take for granted, but they are actually very cognitively demanding” he said.

“If hearing loss imposes a cognitive load, there may be fewer cognitive resources to help with maintaining balance and gait,” he added.

Source: Daily Mail: http://bit.ly/xEKEea

Researchers have been given the go-ahead to test stem cells from cord blood with the ultimate goal of reversing hearing loss in infants and toddlers whose inner ears have been damaged. U.S. regulators have approved the Phase I study, which has a primary objective of determining the safety of the experimental stem cell therapy.

The therapy involves transfusing a baby’s own stem cells from umbilical cord blood, banked by parents after their child’s birth. Ten children aged six weeks to 18 months old with sensorineural hearing loss will be recruited for the study by doctors at Children’s Memorial Hospitalin Huston.

“We’re looking more at the ones that suffer an injury around birth or shortly after birth,” said Dr. Samer Fahkri, a specialist in head and neck surgery and principal investigator of the study.

Fakhri, a Montreal native, who received his medical training at McGill University, said such injuries to the inner ear can be caused by viral infections and even some medications.

Sensorineural hearing impairment occurs when structures in the inner ear or the nerve pathways between the inner ear and the brain are damaged. The critical structure in the inner ear is the snail-shell-shaped cochlea, which contains “hair cells” that gather electrical signals, which are transferred to the brain and perceived as sound.

A child with this kind of hearing loss can suffer significant impairment, Fakhri said. “You may hear parts of sounds. You may not hear the sounds at all, or you may hear vary faint sounds.

“If they lose hearing at four weeks or five weeks due to a viral infection” – meningitis is a common cause – “we know that there is a tremendous impact,” he said.

“There’s a lot of research that has been done in child development that has determined that there’s really a critical window for children to develop speech, language, and social development, and it’s probably in the first 18 months.”

The idea for the trial was triggered by a 2008 study by European scientists who infused human cord blood into laboratory mice with induced sensorineural hearing loss. An examination of the treated animals about two months later showed “inner ear organization and structure were basically restored,” said Fakhri.

“That was the study that was a proof of concept … That was such a dramatic result.”

Fakhri said the roll of the stem cells in the repair of damaged tissue in the mice isn’t known, but there are a couple of theories.

Stem cells can give rise to many different types of cells in the body, so it may be the effect the repair by regeneration of lost hair cells. But a more recent theory suggests that stem cells may go to the site of injury and set off the body’s innate repair mechanisms.

“In that sense, they play more of a supporting role,” he said.

While regeneration tissues is the great hope of stem cells – and they do appear to hold a lot of promise – the idea that they could restore damaged hearing in humans is still speculative, doctors say.

“This study is really very, very preliminary,” said Dr. Robert Harrison, a professor of head and neck surgery at the University of Toronto.

“That’s the safety issue,” he said, stressing that the FDA-approved study must first ensure the stem cells do no harm to the patients. Figuring out if they actually work to repair the organ of hearing would have to be proven in subsequent trials.

“We’re a long way from looking at the possible therapeutic value of this in terms of restoring some sort of hearing,” said Harrison, a senior scientist at the Hospital for Sick Children and a doctor of the Hearing Foundation of Canada.

“It’s a very theoretical concept, and in my opinion it’s not going to happen soon.”

Current treatment of sensorineural hearing loss in young children is pretty well restricted to hearing aids or cochlear implants, surgically implanted electronic devices, Fakhri said. Both are used to amplify any residual hearing.

For more information: http://www.ctv.ca/CTVNews/Health/20120210/stem-cells-cord-blood-hearing-loss-kids-120210/#ixzz1m5DV1LDC