Motor evoked potentials in clinically isolated syndrome suggestive of multiple sclerosis.
The aim of the present study was to determine the sensitivity and the profile of motor evoked potentials (MEP) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). We measured the central motor conduction time (CMCT), amplitude ratio (AR), and surface ratio (SR) in tibialis anterior and first dorsal interosseous muscles in 22 patients with CIS. In 12 patients, the triple stimulation technique (TST) was also performed. AR was abnormal in 50% of patients, CMCT in 18% of patients, and TST in 25% of patients. AR had the highest sub-clinical sensitivity and the best positive predictive value. In the absence of clinical pyramidal signs, an early AR decrease seems to result from demyelination inducing excessive temporal dispersion of the MEP, while in territories with clinical pyramidal signs, it seems to result from conduction failure, which suggests that clinical pyramidal signs may be attributable to conduction failure. This study demonstrates that MEP, especially the AR, is sensitive to motor pathway dysfunction right from the early stages of MS.
Rico
A
A
Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Pôle de Neurosciences Cliniques, Service de Neurologie, Université de la Méditerranée, Hôpital de la Timone, Marseille, France. audrey.rico@ap-hm.fr
Audoin
B
B
Franques
J
J
Eusebio
A
A
Reuter
F
F
Malikova
I
I
Ali Cherif
A
A
Pouget
J
J
Pelletier
J
J
Attarian
S
S
D000328:Adult; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000503:physiopathology; D042241:Early Diagnosis; D004568:Electrodiagnosis / Q000379:methods*; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000503:physiopathology*; D009431:Neural Conduction; D011446:Prospective Studies; D011712:Pyramidal Tracts / Q000503:physiopathology; D012680:Sensitivity and Specificity; D055815:Young Adult