Evoked potentials in early MS correlate with disability

Evoked potentials (EPs) is a technique that allows us to test the electrical conduction in a particular pathway within the nervous system. If the conduction is slow it tells us the particular pathway being tested is demyelinated. 

EPs can be very helpful in making a diagnosis of MS; EPs can be used to show sub-clinical or asymptomatic involvement of a particular pathway.

Aim: This study assessed combined EPs as a marker and predictor of the disease course of early MS over 3 years.

Methods: 50 MS'ers in the early phase of RRMS prospectively underwent visual, sensory and motor EPs and disability (EDSS) assessments at baseline and at 6months intervals for 3years. 

Results: EDSS correlated with the sum of the EPs. The change in the sum of the EPs correlated with the change of EDSS

Conclusions: EPs correlate well with clinical disability in cross-sectional and longitudinal comparison in early MS and allow prediction of disease evolution over a period of 3 years.

Epub ahead of printSchlaeger et al. Combined evoked potentials as markers and predictors of disability in early multiple sclerosis. Clin Neurophysiol. 2011 Jul 19.

"Why is this study important? Firstly, it confirms that EPs can be useful in the diagnosis of MS. More importantly, however, this study shows that EPs may be suitable as a marker of remyelination. If for example you have a delayed visual EP, for example instead of conduction at 100 milliseconds your left optic nerve conducts at 120milliseconds, an effective remyelination therapy would have to reduce this delay."

"EPs will almost certainly be used to assess remyelination thearpies."

"Do you know what the clinical effects of delayed conduction speed in an the visual pathway?"

Additional reading: evoked potential