A mentally active lifestyle might protect against the cognitive decline associated with brain damage caused by multiple sclerosis, researchers said.
In a small cohort study, higher intellectual achievement acted as a buffer against learning and memory declines associated with atrophy of brain tissue, according to James Sumowski, PhD, of the Kessler Foundation Research Center in West Orange, N.J., and colleagues.
The finding supports the idea that a so-called "cognitive reserve" might explain why some MS patients with severe disease don't show the same cognitive declines as others with the same degree of damage, Sumowski and colleagues wrote in the June 15 issue of Neurology.
"Learning and memory ability remained quite good in people with enriching lifestyles, even if they had a lot of brain damage," Sumowski said in a statement. "In contrast, persons with lesser mentally active lifestyles were more likely to suffer learning and memory problems, even at milder levels of brain damage."
One possible implication, the researchers argued, is that patients with lower "lifetime intellectual enrichment" might benefit from cognitive rehabilitation in the early stages of the disease. But they cautioned that more research is needed to establish the value of such enrichment.
The notion of a cognitive reserve has been studied mainly in Alzheimer's disease, where there is "significant support" for the idea, according to Peter Arnett, PhD, of Penn State University in University Park, Pa.
In an accompanying editorial, Arnett said the current study supports the idea that a cognitive reserve also plays a role in buffering the effects of brain atrophy in MS patients, introducing "a potentially modifiable variable that could reduce or prevent cognitive problems in MS."
To examine the issue, the researchers enrolled 44 people with a mean age of 44.9, who had had MS for 10.5 years on average. They had an average of 16.1 years of education.
The researchers estimated brain atrophy by magnetic resonance imaging to find the third ventricle width, which they described as the best neuroanatomic predictor of learning and memory performance in patients with MS.
And they estimated intellectual enrichment with the vocabulary subtest of the Wechsler Abbreviated Scale of Intelligence, which assesses the depth and breadth of acquired vocabulary knowledge, typically acquired through reading and education.
In the test, patients were asked to learn a list of 10 words and asked to recall them 30 minutes later, the researchers said in a statement.
When patients were divided into subgroups based on scores on the test and amount of brain atrophy, the researchers found a significant three-way interaction -- higher brain atrophy was associated with inefficient learning among patients with lower intellectual enrichment, but not patients with higher intellectual enrichment.
Specifically, they said in the statement, among people with higher intellectual enrichment, learning and recall was similar in those with lower and higher amounts of brain damage -- a decline in recall of about 1%, 9.6 words on average compared with 9.5 words.
But among patients with less intellectual enrichment, learning and recall were worse among those with higher amounts of brain damage -- a drop in recall of about 16%, 9.6 words on average compared with 8.0 words.
The implication, the researchers argued is that enrichment reduces the negative cognitive consequences of the disease, rather than increasing cognitive abilities in general. "When there is little or no disease," they said, "there is little or nothing to protect against."
Sumowski and colleagues cautioned that the findings may not be widely applicable because the patients in the sample had an unusually high education level.
Arnett called the study "provocative," but also cautioned that it should be taken with a grain of salt, in part because the authors used a single limited measure of learning and memory.
The study was supported by the National Multiple Sclerosis Society and the NIH.
The researchers reported that they had no financial links with industry.
Arnett reported that he does not have any financial links with industry.
- Reviewed by Ari Green, MD Assistant Professor, University of California, San Francisco and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
NeurologySource Reference: Sumowski JF, et al "Intellectual enrichment lessens the effect of brain atrophy on learning and memory in multiple sclerosis" Neurology 2010; 74: 1942-45.
NeurologySource Reference: Arnett PA "Does cognitive reserve apply to multiple sclerosis?" Neurology 2010; 74: 1934-35.