Fatigue and cognitive decline in MS

There’s a moving story about a man’s struggle with multiple sclerosis (MS) on the front page of today’s Wall Street Journal (After Diagnosis, A New Dilemma: What to Tell Boss?). Kenneth Bandler hid his disease from his employer because he was afraid he would be pitied at work and constantly asked about his condition.The article reports that many MS patients leave the work force, "often long before disabilities required them to." An expert cited in the article believes it may be due to cognitive problems that MS patients suffer.I asked Dr. Robert Paul, a Brown University neuropsychologist who has studied MS and cognition, for his opinion.

One of the most common debilitating side effects of MS is fatigue. When people feel tired, they feel that they can’t perform well on cognitive tasks. But it turns out that their cognition doesn’t suffer as much as they think when they are tired.We did a study where we gave MS patients a cognitive test, then a test designed to fatigue them, and then a followup cognitive test. MS patients did not perform quite as well as healthy controls on the cognitive tests at the beginning of the assessment, and they reported much more fatigue than controls. Further, MS patients reported significantly more fatigue after the work battery compared to controls , and they thought their cognition had suffered. But it turned out they did just as well on the followup cognitive test as on the initial one." These findings suggest that fatigue may not have a significant additional impact on cognitive function in MS.

Part of the problem is a lack of sufficiently sensitive cognitive test batteries. Dr. Paul has been involved in the development of new, sensitive computerized batteries as part of the Brain Resource Company.The reference for the study is Paul, R., Beatty, W.W., Schneider, R., Blanco, C.R., Hames, K. (1998). Cognitive and physical fatigue in multiple sclerosis: Relationships among self-report, objective performance and depression. Applied Neuropsychology, 5 (3), 143-148.