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Hi,

These tests are often used in helping to diagnose MS.

[SIZE=-1]Evoked Potential (EP) tests[/SIZE]
[SIZE=-1]Evoked Potential tests are procedures for measuring the speed of impulses along neurons. Responses can be measured using EEG readings from electrodes attached to the scalp and occasionally other areas of the skin. Although this may sound like something from Frankenstein, they are in fact completely painless and entirely harmless. Based on input signals to the particular sense being measured, the time taken for that response to register can be accurately measured and compared to normal readings. The results are then analysed on a computer and average speeds recorded.[/SIZE] [SIZE=-1]Demyelinated neurons transmit nerve signals slower than non-demyelinated ones and this can be detected with EP tests. Although they may appear to function perfectly, even remyelinated neurons are slower than normal nerves and so historical lesions can be detected in this way.[/SIZE]
[SIZE=-1]SomatoSensory Evoked Potential (SSEP)[/SIZE]
[SIZE=-1]The SSEP test involves strapping an electrical stimulus around an arm or leg. The current is switched on for 5 seconds and electrodes on the back and skull measure the response at particular junctions. The current is very low indeed and completely painless. The speed of various nerves can be measured in this way and the points of slow-down (i.e. demyelinated lesions) approximated to because of the sampling at several places.[/SIZE]
[SIZE=-1]77% of people with definite MS and 67% of people with probable MS will have abnormal SSEP test results.[/SIZE]
http://www.mult-sclerosis.org/diagnosingms.html
 
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