How Does Multiple Sclerosis Cause Cognitive Impairment?

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MS probably starts, early in life it's not until your aged 30 that it really becomes manifest. To those patients who present with the very first symptom, if you do formal cognitive testing on those people. A typical cognitive battery, assesses about seven different domains of cognitive functions memory, attention, reasoning and so on.

You will find, that 25% will fail two or three of those batteries, two or three. The day you present it with optic neuritis, because there's brain lesions that have not been noticed. They haven't caused symptoms that the person is aware of, by the time you had MS for five five years it goes from 25 to about 50% who have failed two or more of those tests. Very important element of MS and one that is not readily appreciated of the bedside even by the patient for that matter.

It's not until the cognitive problems become more severe that people start to take notice, the family, the patient, the doctor maybe. By that stage is really too late because that's usually the harbinger of the progressive phase of MS, where people have had those relapses than remitting conditions at first. 15 years later when you start getting the cognitive problems that are really obvious, that means disease has entered the secondary progressive phase.

Relapsing, remitting has turned into this progressive form, where unfortunately our therapies have no effect. So again, the reason to be vigilant at the very beginning is to try to prevent this kind of an outcome, because once that progression occurs it's not treatable, at least today