Memory and Thinking Problems in Multiple Sclerosis
Memory and thinking problems are among the more common signs of multiple sclerosis (MS), even during the early stages, but they are not well understood. To help patients and clinicians better understand cognitive function in MS, researchers have been conducting various studies, several of which are presented here.
About half of all patients with MS experience some cognitive impairment, although in most cases it has a mild to moderate impact. In 5 to 10 percent of cases, however, it is more severe and disruptive to a person’s lifestyle.
The most recently reported research looked at the progress of cognitive decline in people who had been diagnosed with early MS. Thirty individuals with MS were followed over a 6.1-year period and evaluated for attention, verbal and motor functions and reasoning, information processing, and memory and learning.
The authors noted that even though the participants showed a significant reduction in dual tasks (divided attention) and information-processing speed during follow-up, they did not exhibit a significant reduction in overall cognitive functioning. This information may prove helpful for people who suffer with MS and for their healthcare providers so they can be aware of the possibility that these cognitive challenges may occur.
In another new study, the investigators sought to understand the role of the neurotransmitter glutamate in the brain in patients with MS. A neurotransmitter is a brain chemical that carries or relays signals between neurons (nerve cells).
Glutamate is a nonessential amino acid and the main excitatory neurotransmitter, which means it can stimulate the brain. Another type of neurotransmitter is the inhibitory variety, which perform a contrasting role: they calm and balance the brain.
In the study, the researchers identified the glutamate levels in the brains of 18 patients with relapsing-relapsing MS and in 17 healthy controls. Here is what they observed:
- Individuals with MS had worse verbal and visual memory than did controls
- There was a positive relationship between glutamate levels in the brain and visual and spatial memory in individuals with MS but not in the controls. The authors concluded that the relationship between memory and the concentration of glutamate in the brain is unique to patients with MS and that memory in these individuals depends on the activity of glutamate in the body.
Are depression and fatigue, two other common symptoms of MS, also related to cognitive dysfunction in patients with the disease? The conclusion of another new study is that the former but not the latter is related to cognitive decline.
A total of 184 Japanese patients with MS and 163 healthy controls participated in the study. Various tests were used to determine cognitive function (the Brief Repeatable Battery of Neuropsychological tests), fatigue, depression, and apathy in both groups.
Individuals who had MS scored significantly lower than did controls on all the battery tests (5 tests)
Patients with MS had higher scores on the tests for fatigue, depression, and apathy than did the controls
The investigators saw a correlation between the low scores on the battery of neuropsychological tests and depression and apathy but not on battery scores and fatigue
In this study, the authors saw a relationship between impaired cognitive function and apathy and depression, but not between fatigue and brain impairment. This finding is important because it suggests the treatment strategies for improving fatigue and cognitive problems are different.
It’s important to point out that the medications used by many patients who have MS can in themselves cause cognitive problems. Antidepressants, tranquilizers, steroids, cholesterol-lowering medications, and muscle relaxants all can affect thinking and memory.
What are the treatment options for cognitive problems in MS? Thus far, medications that may help slow the progression of cognitive problems in MS include Avonex (interferon beta-1a) and Betaseron (interferon beta-1b). Tysabri (natalizumab) and the Alzheimer’s drug Aricept (donepezil) also have been shown to improve cognition when compared with placebo.
Stress can exacerbate memory and cognitive functioning problems. The practice of stress management techniques, such as meditation, yoga, progressive relaxation, or tai chi may be helpful.
If you have MS and have been experiencing cognitive difficulties, how do you handle these challenges? Have you spoken to a healthcare provider about the possible contribution your medications may have on thinking and memory problems?
Hankomaki E et al. The progress of cognitive decline in newly diagnosed MS patients. Acta Neurologica Scandinavica 2014 Mar; 129(3): 184-91
Muhlert N et al. Memory in multiple sclerosis is linked to glutamate concentration in grey matter regions. Journal of Neurology, Neurosurgery & Psychiatry 2014 Jan 15
Niino M et al. Apathy/depression, but not subjective fatigue, is related with cognitive dysfunction in patients with multiple Sclerosis. BMC Neurology 2014 Jan 6; 14(1): 3