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Resistance Training Might Delay Onset Of Dementia
Thursday 03 May 2012 - 19:03:58 | International Physiotherapy News
According to a study published in published in the Archives of Internal Medicine, six months of twice-weekly resistance training (RT) improved executive function, associative memory, and regional patterns of functional brain plasticity in a group of older women with probable mild cognitive impairment (MCI).
"We provide novel evidence that RT can benefit multiple domains in those at risk for dementia, We found improvement in both cognitive and brain function with resistance training — not just maintenance — over the 6 months. Thus, our results imply that resistance training can delay the onset of dementia in older adults," first author Teresa Liu-Ambrose, PhD, PT, from the Aging, Mobility, and Cognitive Neuroscience Laboratory, University of British Columbia, Vancouver, Canada, told Medscape Medical News.
"Among individuals with MCI, over half will develop dementia in the next 5 years," Dr. Liu-Ambrose noted. "Our finding is new and greatly extends our current knowledge about the potential benefit of exercise in reducing the risk of dementia in older adults."
The Exercise for Cognition and Everyday Living (EXCEL) study enrolled 86 community-dwelling women aged 70 to 80 years with probable MCI (defined as a score < 26 [of 30] on the Montreal Cognitive Assessment) and subjective memory symptoms. They were randomly allocated to twice-weekly, instructor-led classes (60 minutes each) of RT (28 women), aerobic training (AT; 28 women) or balance and tone training (BAT; 30 women, control group) for 6 months.
For RT, both a Keiser Pressurized Air system and free weights were used. Participants performed 2 sets of 6 to 8 repetitions, and loading was increased when sets were completed with proper form. The AT program involved walking outdoors at 40% of a participant's age-specific target heart rate and progressed to 70% to 80% of target heart rate. The BAT program comprised stretching, range of motion, balance exercises, and relaxation techniques.
Seventy-seven (89.5%) of the 86 participants completed the trial (26 in the RT group, 24 in the AT group, and 27 in the BAT group). Twenty-two participants were included in a functional magnetic resonance imaging analysis (7 each in the RT and AT groups and 8 in the BAT group).
After 6 months, compared with the BAT group, the RT group showed significantly improved performance on the Stroop test (P = .04), an executive cognitive test of selective attention/conflict resolution, which was the primary outcome. The RT group also performed significantly better on an associative memory task (P = .03). Compared with BAT, RT also led to functional changes in 3 regions of the cortex — the right lingual (P = .03) and occipital-fusiform (P = .02) gyri and the right frontal pole (P = .03) — during the associative memory task. The researchers also found a significant positive correlation between change in hemodynamic activity in the right lingual gyrus and change in behavioral associative memory performance (P = .02). Twice-weekly AT significantly improved general balance (P = .03) and cardiovascular capacity (P = .04) compared with BAT.
"This small study provides evidence that weekly resistance and aerobic training programs can improve brain blood flow and in so doing increase performance on memory tests," Cyrus A. Raji, MD, PhD, University of Pittsburgh Medical Center Mercy Hospital, Pennsylvania, who was not involved in the study, says. "While the study was limited to elderly females, women as a group are at a higher risk for Alzheimer's, making the findings of the study timely and relevant. Larger studies need to be done looking at combinations of different physical activity regimens across gender and wider age ranges," Dr. Raji added.
Dr. Liu-Ambrose cautioned that although RT was "more beneficial" than AT in promoting both cognitive and brain function, "more research is needed to refine exercise prescription for optimal benefit." Dr. Raji agrees. While this study "seems to suggest that [RT] is more beneficial that [AT], caution must be exercised in interpreting the results because more people dropped out of the [AT] group," he said.
Differences in both the frequency and intensity of AT regimens between the 2 studies may underlie the differing results, Dr. Liu-Ambrose and colleagues note in their report. In addition, the women in their study were older and had lower baseline Mini-Mental State Examination scores.
Device to help injured nerves to regrow faster.
Saturday 28 April 2012 - 21:09:48 | Non Physiotherapy News
Nerve damage caused by traumatic accidents may heal faster after researchers at University of Sheffield developed a new method that could make medical devices help the nerves to repair naturally. The devices called nerve guidance conduits or NGCs will help to regrow after injury. The method is based on laser direct writing, which enables the fabrication of complex structures from computer files via the use of CAD/CAM (computer aided design/manufacturing), and has allowed the research team to manufacture NGCs with designs that are far more advanced than previously possible.
Currently patients with severe traumatic nerve damage suffer a devastating loss of sensation and/or movement in the affected limb. The traditional course of action, where possible, is to surgically suture or graft the nerve endings together. However, reconstructive surgery often does not result in complete recovery.
"When nerves in the arms or legs are injured they have the ability to re-grow, unlike in the spinal cord; however, they need assistance to do this," said University of Sheffield Professor of Bioengineering, John Haycock. "We are designing scaffold implants that can bridge an injury site and provide a range of physical and chemical cues for stimulating this regrowth," he stated.
The new conduit is made from a biodegradable synthetic polymer material based on polylactic acid and has been designed to guide damaged nerves to re-grow through a number of small channels.
"Nerves aren't just like one long cable, they're made up of lots of small cables, similar to how an electrical wire is constructed," said lead author Dr Frederik Claeyssens, of the University's Department of Materials Science and Engineering. "Using our new technique we can make a conduit with individual strands so the nerve fibres can form a similar structure to an undamaged nerve," Claeyssens added. Once the nerve is fully regrown, the conduit biodegrades naturally.
The team hopes that this approach will significantly increase recovery for a wide range of peripheral nerve injuries. In laboratory experiments, nerve cells added to the polymer conduit grew naturally within its channelled structure and the research team is now working towards clinical trials.
"If successful we anticipate these scaffolds will not just be applicable to peripheral nerve injury, but could also be developed for other types of nerve damage too. The technique of laser direct writing may ultimately allow production of scaffolds that could help in the treatment of spinal cord injury," said Dr Claeyssens. "What's exciting about this work is that not only have we designed a new method for making nerve guide scaffolds which support nerve growth, we've also developed a method of easily reproducing them through micromolding. This technology could make a huge difference to patients suffering severe nerve damage," he added.
Sourced from : http://www.medindia.net
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