Multiple Sclerosis: A long known unknown

Multiple Sclerosis is a nervous system disease that results in both cognitive impairment as well as physical impairment.  It is well known as a demylinator of axonal nerves. Typically physical impairment is more often observed.  Cognitive impairment exhibits itself due to the demyelination of white matter but also axonal damage and grey matter damage as well.  The disease leads to impaired decision making, loss of employment, driving abilities, and social functioning.  Difficulty with complex attention, information processing speed, memory retrieval, verbal fluency, visospatial memory, and working memory as well.  As of now there is no standardized way to measure cognitive impairment but some groups of neurologists are starting to address this issue.  The physical impairment that occurs as a result of MS can be directly correlated to changes in brain activity as measured by an MRI.  However the cognitive functioning is not so closely correlated with this brain sclera.   It is predicted that the networks that handle working memory (a functionally interconnected group of brain regions that work together) may be interrupted or even severed due to the damage of brain white matter.  There has been some measured evidence of axonal remapping and repaired cognitive functioning in patients with MS as well.

A patient who is suffering from a severe form of MS.

One of the first recorded accounts of cognitive defects in patients with MS was in 1877 by Charcot. He noted that at particular stages of the disease patients showed difficulty with memory, forming concepts, and intellectual and emotional bluntness.

Although this is true most physicians ignored this aspect of the disease until 1986 when Stephen Rao’s research shed light on the cognitive aspects of the disease.  One of the major difficulties in the treatment and measurement of the disease is that there seems to be no patterning In terms of the breakdown of brain tissues.  This means its very hard to say which patient will exhibit what types of symptoms or even at what severity they will exhibit.

Current treatment for patients suffering from MS targets the physical changes associated with the lesions only as well as depression and fatigue.  It does not address cognitive impairment.

Current treatment aims to slow down the progression of the disease itself as a means to help reduce the amount of cognitive deterioration that occurs.  B interferon (an immuno modulating drug that aims to reduce inflammation) is currently used.

Other treatments aim to use Alzheimer’s drugs such as donepezil, rivastigmine and galantaime due to their action as aceytlcholinesterase inhibitors.  The drugs act by blocking the enzyme acetylcholinesterase thus increases the amount of neurotransmitter which has an augmenting effect neurologically.  Many diseases such as Acute encephalomyelitis and Alzheimer’s all of which exhibit cognitive impairment might be good indicators of how to treat MS.

Patients with higher levels of cognitive impairment exhibit enlargement of the third ventricle.   This suggests a relevance to the damage of the surrounding tissues such as the thalamus.  Patients with MS were found to have a16.8 % lower thalamic volume than the Normal Control patients.  This suggests the thalamus of patients who come down with MS is atually shrinking. The thalamus is involved in limbic circuitry and it mediates many cognitive functions which is intersting considering the symptoms many MS patients have.

A cross section of the brain through the corpus calosum. Here you can see the thalamus.

New breakthroughs in medicine however might prove beneficial to patients suffering from MS.  Cognitive dysfunction is becoming more and more the target of pharmacological interest which implies that we might be seeing better more specific drugs in the future than can help alleviate these debilitating side effects.

Posted on May 18, 2010, in Medicine and tagged , , , , , , , , , , , , , , , . Bookmark the permalink. 3 Comments.

  1. Lara Shapiro-Snair

    Thanks for the information! I have my appointment on July 22 with one of the experts in the field at UCLA (she co-authored MS for Dummies…lol!)

    Keep me posted!

  2. Have you ever thought about publishing an e-book or guest authoring on other sites? I have a blog centered on the same information you discuss and would really like to have you share some stories/information. I know my readers would appreciate your work. If you’re even remotely interested, feel free to send me an email.

  1. Pingback: Zeitgeist Studios » Blog Archive » Monday Mood Board: Head of State

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