ST. PAUL, Minn. – New insights into risk factors for Parkinson's disease and stroke, new understanding of disease mechanisms in multiple sclerosis, and new treatment possibilities for pain, epilepsy, and ALS were among the scientific highlights at the 57th Annual Meeting of the American Academy of Neurology (AAN), where results from more than 1,400 scientific studies were presented. Some of the most important findings were presented in a plenary session moderated by John H. Noseworthy, MD, chair of the AAN Science Committee and Scientific Program Subcommittee and chair of the department of neurology at Mayo Clinic in Rochester, Minn. Highlights included:
Active duty military service increases the risk of developing Parkinson's disease, according to researchers from California. Men who served in World War II and Vietnam were twice as likely to develop Parkinson's as those who were in the military at the same time but were not deployed overseas. [S27.005] Meanwhile, taking ibuprofen, but not other nonsteroidal anti-inflammatory drugs (NSAIDs), reduced the risk of Parkinson's by about 40 percent in both men and women, adding to the growing list of conditions for which NSAIDs appear to offer protection. [P05.073]
The known genes for Parkinson's disease account for only a small percent of all cases. At the meeting, researchers described the most recent gene discovery, LRRK2, whose function is not yet known, which may be responsible for up to one percent of all Parkinson's cases, and six percent or more of inherited forms. [S17.001]
Donepezil is commonly prescribed for the dementia of Alzheimer's disease. In a large, multi-year study, researchers showed donepezil can also temporarily slow the transition from mild cognitive impairment for a period of up to three years, a pre-Alzheimer's form of dementia, to full Alzheimer's disease. Its effects were especially strong in those patients with a known genetic risk factor for Alzheimer's, the APOE-4 allele. In the same study, vitamin E was not found to slow cognitive decline. [plenary session]
A potentially important experimental therapy for Alzheimer's disease is the use of antibodies against the beta-amyloid, a protein that accumulates in the brain of Alzheimer's patients and is thought to hasten cognitive decline. In a mouse model of Alzheimer's disease, researchers from Indianapolis showed that administering antibodies against beta-amyloid decreased the level of the protein in the brain after two weeks of treatment, providing the proof of principle for trying the same experimental approach in humans. [S55.002]
Dementia may also occur in essential tremor, according to researchers from Spain and New York. Essential tremor affects approximately 10 million Americans, and is characterized by shaking during use of a limb. The risk for developing dementia was twice as high in people with essential tremor as in those unaffected by the disease. Essential tremor has not previously been linked with an increase risk for cognitive difficulty. [P05.078]
Two studies reported on mechanisms by which neurons are damaged in multiple sclerosis (MS). Researchers in Germany and New York showed that when immune cells destroy the insulating myelin around neurons, a molecule called 7-ketocholesterol is released. This molecule may stimulate other immune cells to attack the neuron. Understanding this important step may help design therapies to block it. [S12.004] Meanwhile, researchers from the United Kingdom discovered that in neurons from a mouse model, the number of mitochondria is increased, and the mitochondria are more active. Mitochondria are the cell's power-generating plants, and it is possible that the increase reflects an increased need for energy in the vulnerable neurons. Neuronal loss may occur partly due to the inability to keep up with energy demands. [S12.005]
A common cause of headache is overuse of headache medications. These headaches are difficult to treat once they occur, since withdrawing all medications often makes the headache even worse. A study from Germany showed that patients who took prednisone for five days during withdrawal had headaches that lasted only about half as long as those who received no treatment. This therapy may help patients with medication-overuse headaches who attempt to stop using headache drugs. [S59.005]
Neuropathic pain is a common and dreaded complication of spinal cord injury, and has proven very hard to treat. Researchers in Germany, Australia, and the United States showed that pregabalin, a drug used for diabetic neuropathic pain, is also effective for relieving centrally generated neuropathic pain after spinal cord injury. It reduced pain by about 25 percent versus placebo. Its effects were seen within one week, and lasted for the full 12 weeks of the study. [S49.001]
Lennox-Gastaut syndrome is a severe form of childhood epilepsy that is difficult to treat with standard medications. Researchers in Maryland and New Jersey showed that in treatment-resistant patients, the novel drug rufinamide reduced monthly seizure frequency by 33 percent, compared to 12 percent for placebo, and seizure severity was also significantly reduced. [LBS.001]
There are currently no treatments for prion diseases, including Creutzfeldt-Jakob disease, some cases of which have been linked to mad cow disease. There is also no known way to prevent infection with prions, which are aberrant proteins that may be transmitted through food, blood transfusion, or organ donation. A study from researchers in New York and Ohio showed that susceptibility to prion infection can be reduced in mice by treatment with a monoclonal antibody to the prion. Further development of this strategy may also offer hope for treatment of these diseases. [P04.149]
Temozolomide chemotherapy plus radiation is superior to radiation alone in treatment of glioblastoma multiforme, a type of brain cancer, according to a new study. Six weeks of treatment led to a better than two-fold increase in survival of patients two years later, which translated into a 37 percent reduction in risk overall from this deadly and difficult-to-treat form of brain cancer. [plenary session]
Tamoxifen may increase survival in patients with amyotrophic lateral sclerosis (ALS), according to a study from researchers in Wisconsin. The drug, which is also used to treat breast cancer, has been shown to improve survival in a mouse model of the disease, but a 12-month trial in ALS patients did not show an effect. The current trial extended the earlier trial to 24 months, and examined five different doses of the drug. Results showed that patients taking the highest doses lived for up to 200 days longer than those receiving the lower doses. Larger trials are now planned to confirm this effect. [S13.001]
Stroke is one of the leading killers of adults. Researchers from Cincinnati found the risk for ischemic stroke, the type caused by a blocked blood vessel in the brain, is higher in people with particular forms of a gene called phosphodiesterase 4D. People with the high-risk forms, who may comprise up to 22 percent of the population, have an approximately 50 percent greater risk than those without these forms of the gene. In addition to the importance of these results for predicting stroke risk, they may point the way to risk-reducing interventions based on this gene. [P01.092]
The same group of researchers showed that survival after a stroke caused by intracerebral hemorrhage has not improved in more than a decade. Mortality is high immediately after such a hemorrhage, with about half of all patients dying within the first year, and less than 20 percent surviving 10 years or more. Comparing figures from 1998 to those from 1998 to 2003, researchers found no difference in overall mortality or the risk per year after the hemorrhage. These data point out the lack of effective treatments for patients with intracerebral hemorrhage, and the urgent need to develop new therapies. [S43.001]
The AAN 57th Annual Meeting was held April 9 – 16, 2005 in Miami Beach, Fla. It is the world's largest annual gathering of neurologists.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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