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Effects of High Stimulus Frequencies on SEPs of Patients with Neuro-Behcet's Disease

Published online by Cambridge University Press:  02 December 2014

Hande Turker*
Affiliation:
Faculty of Medicine, Department of Neurology, Ondokuzmayis University, Samsun
Nilgun Cengiz
Affiliation:
Faculty of Medicine, Department of Neurology, Ondokuzmayis University, Samsun
Handan Akar
Affiliation:
Faculty of Medicine, Department of Neurology, Ondokuzmayis University, Samsun
Musa K. Onar
Affiliation:
Faculty of Medicine, Department of Neurology, Ondokuzmayis University, Samsun
Onder Us
Affiliation:
Faculty of Medicine, Department of Neurology, Marmara University, Istanbul, Turkey
*
Ondokuzmayis University, Faculty of Medicine, Department of Neurology, 55139 Samsun, Turkey
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Abstract

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Background:

Behcet's disease is a multisystemic vascular inflammatory disorder of unknown origin. It is relatively rare and central nervous system involvement is seen in 5% of affected individuals. Somatosensory evoked potentials (SEPs) can provide information that shows the presence of clinically unsuspected lesions in the central nervous system of these patients. However, the effects of changing the stimulus frequencies on latencies of SEP potentials and central conduction time (CCT) in patients with neuro-Behcet's disease (NB) have not been studied yet. In this study, our aim was to reveal these effects to investigate whether the change of stimulus frequencies could be of convenient use in obtaining more accurate CCT estimations in SEP studies of these patients.

Methods:

We performed median nerve SEPs of 14 patients with NB and 15 healthy volunteers. We changed the stimulus frequency: 2 Hz, 4Hz, 6Hz and 9Hz in successive recordings and statistically compared the changes on SEP potentials and peak and onset CCT in the neuro-Behcet (NB) group and the normal group.

Results:

Our results indicated that the onset CCT values of the NB group were higher than the normal group at 4Hz and 9Hz stimulations. However, the comparison of peak CCT in the NB group and the normal group did not show any statistically meaningful differences at all stimulation frequencies.

Conclusion:

Onset CCT has not been measured before in former SEP studies of patients with NB. We highly recommend measuring onset CCT at higher stimulation frequencies in order to reveal central conduction time pathologies in these patients.

Résumé:

RÉSUMÉ:Contexte:

La maladie de Behcet est une maladie inflammatoire vasculaire multisystémique d’étiologie inconnue. C’est une maladie relativement rare et le système nerveux central est atteint chez 5% des cas. Les potentiels évoqués somesthésiques (PÉSs) peuvent démontrer chez ces patients la présence de lésions du système nerveux central qui sont silencieuses au point de vue clinique. Cependant, on n’a jamais étudié les effets de changements des fréquences de stimulation sur les latences des PÉSs et sur le temps de conduction central (TCC) chez les patients atteints de la maladie de Behcet qui ont une atteinte neurologique (MBN). Le but de cette étude était de démontrer ces effets afin de déterminer si un changement de fréquence du stimulus pouvait être utilisé pour obtenir des estimations TCC plus exactes dans les études des PÉSs chez ces patients.

Méthodes:

Nous avons évalué les PÉSs au niveau du nerf médian chez 14 patients atteints de MBN et 15 témoins en bonne santé. Nous avons varié la fréquence du stimulus, soit 2Hz, 4Hz, 6Hz et 9Hz, lors d’enregistrements successifs et nous avons comparé par analyse statistique les changements observés au niveau des potentiels PÉSs ainsi qu’au niveau du pic et du délai d’apparition du TCC dans le groupe atteint de MBN et le groupe témoin.

Résultats:

Nos résultats indiquent que les valeurs du délai d’apparition du TCC du groupe MBN étaient plus élevées que celles du groupe témoin pour les stimulations à 4Hz et 9Hz. Cependant, il n’y avait pas de différence significative au point de vue statistique entre le pic du TCC chez le groupe MBN et le groupe témoin à différentes fréquences de stimulation.

Conclusion:

Le délai d’apparition du TCC n’a pas été mesuré antérieurement dans les études des PÉSs chez les patients atteints de MBN. Nous recommandons fortement de mesurer le délai d’apparition du TCC à des fréquences de stimulation plus élevées afin de détecter des pathologies du temps de conduction central chez ces patients.

Type
Original Articles
Copyright
Copyright © The Canadian Journal of Neurological 2006

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