About half of all MS patients experience problems with memory and other cognitive functions. These problems are a leading cause of disability for people with MS. There are currently no drugs to treat this symptom of MS.
The study involved 69 people with MS and mild cognitive problems. Half of the participants took the drug donepezil for 24 weeks and the other half took a placebo. The participants were given tests of memory and other cognitive functions at the beginning and end of the study.
At the end of the study, those taking donepezil improved by an average of 14 percent on the memory test, compared to a 3-percent improvement for those taking the placebo. And 66 percent of those taking the drug felt that their memory had improved, compared to 32 percent of those taking the placebo.
"The possibility that memory and cognitive impairment in MS could benefit from drug treatment is of major importance to patients and their families," said study author and neurologist Lauren Krupp, MD, of Stony Brook University Hospital in New York. "Any treatment that would enhance their ability to meet the mental challenges of their daily lives would be helpful."
Krupp said that a larger study should be done to confirm these results.
"MS patients typically take several drugs already, so before any new treatment is added for symptoms, we should have strong evidence that it will truly be beneficial," she said.
There were no serious side effects from the drug. Those taking donepezil were more likely to have unusual or abnormal dreams than those taking the placebo.
The researchers don't know how donepezil may work in the brain to help improve memory in people with MS. Donepezil belongs to a class of drugs called acetylcholinesterase inhibitors. In Alzheimer's disease, the drug blocks the breakdown of acetylcholine.
"MS is not known to result in the reduction of acetylcholine," Krupp said. "But evidence suggests that there is a decrease in cholinergic activity, likely resulting from the disruption of cholinergic pathways by the demyelination and axonal damage to the nerves that occurs in MS."
In an accompanying editorial, P. Murali Doraiswamy, MD, of Duke University Medical Center in Durham, NC, noted that the study is good news for patients and highlights a major unmet need. But he cautioned that several long-term questions still needed to be answered. "For example, how long do you use the treatment, and how do you tell if the drug is no longer working? Are the benefits lost once you stop treatment? Are there long-term risks? Is the treatment cost-effective?"
Doraiswamy also noted that other classes of drugs should be tested for potential benefits for the cognitive symptoms of MS. "Hopefully, such studies in the near future will lead to more treatment options for people with MS."
The study was supported by grants from the National Institutes of Health, the National Institutes for Disability and Rehabilitation Research, the National Multiple Sclerosis Society, and the National Center for Research Resources.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, and multiple sclerosis.
For more information about the American Academy of Neurology, visit its Website at www.aan.com.