Central motor conduction differs between acute relapsing-remitting and chronic progressive multiple sclerosis.
OBJECTIVE
To characterize central motor conduction in relation to the clinical deficits and to the disease duration in 90 patients with acute relapsing-remitting MS (RR-MS) and in 51 patients with chronic primary or secondary progressive MS (P-MS).


METHODS
The triple stimulation technique (TST) was used to quantify the central motor conduction failure (expressed by the TST amplitude ratio) and conventional motor evoked potentials (MEPs) were used to measure the central motor conduction time (CMCT).


RESULTS
The TST amplitude ratio was reduced in presence of a clinical motor deficit (p=0.02 for RR-MS, p<0.01 for P-MS), but did not significantly differ in RR-MS and P-MS (p>0.05) when patients with similar clinical motor deficit were compared. The CMCT was not related to the clinical motor deficit in both RR-MS and P-MS. However, the CMCT was markedly prolonged in P-MS, when patients with similar clinical motor deficit and with similar disease duration were compared (p<0.01). The differences were not attributable to differential involvement of the spinal cord, which was similar in RR-MS and P-MS.


CONCLUSIONS
Our results disclose differences between the central motor conduction in RR-MS and P-MS that are not related to disease severity, spinal cord involvement or disease duration.
Department of Neurology, University of Berne, Inselspital, CH-3010 Bern, Switzerland.
A M
AM
Humm
M R
MR
Magistris
A
A
Truffert
C W
CW
Hess
K M
KM
Rösler
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis / Q000503:physiopathology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology*; D011930:Reaction Time