High-Fat, Low-Carbohydrate Diet Helps Children With Epilepsy
NEW YORK, May 5 (Reuters Health)—The results of a study provide strong evidence that a diet high in fat and low in carbohydrates—a so-called ketogenic diet—can help control seizures in children with stubborn epilepsy that does not respond well to drug therapy.

In their study, Dr. Elizabeth G. Neal, from University College London, and colleagues randomly assigned a group of children who were having at least seven epileptic fits per week despite antiepileptic drug therapy, to a standard diet or a ketogenic one, which is typically high in fats and very low in carbohydrates.

After three months, children on the ketogenic diet had more than one-third fewer seizures, while seizure frequency increased in children on the standard diet, the researchers reported in the June issue of Lancet Neurology.

A greater than 50% drop-off in seizure frequency was noted in 38% of children on the ketogenic diet, compared with just 6% of children on the standard diet.

This study confirmed that a ketogenic diet is safe and effective in children with drug-resistant epilepsy, the investigators concluded. The most common side effects with the ketogenic diet were constipation, vomiting, lack of energy, and hunger, Dr. Neal and colleagues noted.

In a written commentary, Dr. Max Wiznitzer, from the Rainbow Babies and Children’s Hospital in Cleveland, noted that some questions still remain regarding ketogenic diets for childhood epilepsy. Among these are the long-term effects, the identification of epilepsies that benefit from early initiation of such a diet, and the mechanism by which the diet produces its antiseizure effect.

Lancet Neurology. 2008;7(6):500-506.

Shorter Arms, Legs Linked With Greater Dementia Risk
NEW YORK, May 5 (Reuters Health)—People with shorter arms and legs may be more likely to develop Alzheimer’s disease, and poor nutrition in early life is the probable culprit, according to new research published in the May 6 Neurology.

Arm span and knee height are indicators for how well nourished a person was in early childhood, Dr. Tina L. Huang of Tufts University in Boston, who was involved in the study, told Reuters Health. “All those factors that are involved with making a healthy baby are maybe also important in dementia and Alzheimer’s disease risk,” she said in an interview.

Dr. Huang and her team decided to investigate the relationship between limb length and dementia risk, because the portion of the brain that bears the brunt of Alzheimer’s disease develops just as the limbs are growing most rapidly. They looked at 2,798 men and women participating in the Cardiovascular Health Cognition Study who were followed for about five years, during which time 480 developed dementia.

Among women, the researchers found, dementia and Alzheimer’s disease risk decreased as knee height and arm span increased. Women with the shortest arm spans were 50% more likely to have developed dementia than those with the longest arm span, while dementia and Alzheimer’s disease risk fell by 16% for every additional inch of leg length. For men, knee height was not related to dementia or Alzheimer’s risk, but dementia risk fell by 6% for every additional inch in arm span.

Both genetics and environment influence limb length, the researchers noted in their report, although the role of environment is generally greater in developing nations. Studies in elderly South Korean people linked shorter arms and legs to greater dementia risk, Dr. Huang noted, adding that it was “surprising” to find the association in an American population, for whom getting enough to eat was probably not a major problem.

Based on the current study, she added, “We have to think about the quality of nutrition, as well as making sure that people get enough food.”

Neurology. 2008;70(19 Pt 2):1818-1826.

Istradefylline Enhances Benefits of Levodopa for Parkinson’s Disease
NEW YORK, June 2 (Reuters Health)—A new drug called istradefylline improved the response to levodopa in patients with Parkinson’s disease without substantially increasing abnormal and involuntary movements, investigators reported.

Levodopa works by increasing brain levels of dopamine, a nerve-signaling chemical that is markedly reduced in patients with the disease. Although levodopa is considered the most effective drug for Parkinson’s disease, its effectiveness can wane over time and various side effects, including movement problems, may emerge. Treatment with istradefylline, which works differently than levodopa, “offers the potential for alleviating ... symptoms of Parkinson’s disease, as an adjunct to traditional (dopamine-producing) therapy,” Dr. Mark Stacy and colleagues explained in the June 3 Neurology.

Dr. Stacy, at Duke University Medical Center in Durham, North Carolina, and his team conducted a trial among 395 patients whose symptoms were not adequately controlled for two or more hours each day, a period referred to as “off” time. All were receiving levodopa, and 91% received at least one additional dopamine-producing agent. Patients were randomly assigned to istradefylline, at a low or high dose, or inactive placebo.

Compared with placebo, low-dose istradefylline reduced the percentage “off” time by 4.35%, and the high dose reduced it by 4.49%. The benefits of istradefylline persisted throughout the 12-week study.

Neurology. 2008;70(23):2233-2240.

Reuters Health Information: June 2008