Motor Threshold and Motor Cortex Stimulation
The Relationship Between Motor Threshold and Effective Stimulation Threshold During Motor Cortex Stimulation
Motor cortex stimulation (MCS) is a form of brain stimulation for patients with neuropathic pain not responsive to medication. An electrode is placed on the surface of the brain and connected to a programmable battery in the chest.
The strength of stimulation can be individually adjusted by changing the voltage of stimulation. A too high voltage will produce side effects (e.g. seizures) while a too low voltage will not provide pain control. The aim of this study is to analyze the optimal stimulation parameters in patients already implanted with a motor cortex stimulation who have received good pain relief. The actual voltage may vary widely between patients but the investigators feel that there may be an "ideal" voltage if it is measured as a percentage of motor threshold (PMT). If motor threshold is the stimulation voltage that can evoke a muscle contraction then a PMT = 80% would be a voltage that was eighty percent of that value. Although the actual voltage may be widely different between patients, the percentage needed may be very similar. The investigators therefore plan to measure the effect of different percentages of PMT in patients already being treated with motor cortex stimulation.
Systematic analysis of the findings of this study might help the individual participant and future patients to better programming and less side effects.
Aperçu de l'étude
Statut
Les conditions
Intervention / Traitement
Description détaillée
Motor cortex stimulation (MCS) is a form of brain stimulation for patients with medically refractory neuropathic pain. The strength of stimulation can be individually adjusted by changing the voltage of stimulation. Too high voltage will produce side effects (e.g. seizures) while too low voltage will not provide pain control. The aim of this study is to analyze the optimal stimulation parameters in patients already implanted with a motor cortex stimulation who have received good pain relief. The actual voltage may vary widely between patients (because of the individual variations in tissue resistance) but the investigators feel that there may be an "ideal" voltage if it is measured as a percentage of motor threshold (PMT).
If motor threshold is the voltage that can evoke a muscle contraction then a PMT = 80% would be a voltage that was eighty percent of that value. Although the actual voltage may be different between patients, the effective PMT may be similar since it represents a more physiologic measure of stimulation.
Systematic analysis of the findings of this study might help the individual participant and future patients by reducing voltage to the lowest effective setting and reducing the chance of seizures.
Motor cortex stimulation is used in the treatment of neuropathic pain since 1991 but still no guidelines for programming exist and programming is therefore mainly bases on trial and error. This is mostly due to many variables influencing the choice of stimulation parameters and significant individual differences in susceptibility to stimulation. Routinely the motor threshold is determined during programming to identify the superior limit of voltage at which twitching is induced. No stimulation above the motor threshold should be performed as this is known to cause seizures. The voltage of simulation that will be effective for an individual is unknown at the beginning of the treatment.
The investigators try to find the lowest effective voltage because that will reduce the risk of stimulation-induced seizures and prolong the life of the pacemaker.
Type d'étude
Inscription (Réel)
Phase
- N'est pas applicable
Contacts et emplacements
Lieux d'étude
-
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British Columbia
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Vancouver, British Columbia, Canada, V5Z 4E3
- Vancouver General Hospital
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-
Critères de participation
Critère d'éligibilité
Âges éligibles pour étudier
Accepte les volontaires sains
Sexes éligibles pour l'étude
La description
Inclusion Criteria:
- Adult patient more than 18 years of age
- Chronic neuropathic pain effectively treated with motor cortex stimulation
- Stable medication during the trial
- Willing and able to comply with the study protocol and to return per the follow-up visit schedule and able to provide informed consent.
Exclusion Criteria:
- Evidence of an active disruptive psychiatric disorder or other known condition significant enough to impact the perception of pain, compliance to intervention and/or ability to evaluate treatment outcome as determined by the investigator
- Technical malfunction of the MCS device
- History of seizures
- Unable to provide informed consent
Plan d'étude
Comment l'étude est-elle conçue ?
Détails de conception
- Objectif principal: Traitement
- Répartition: Randomisé
- Modèle interventionnel: Affectation croisée
- Masquage: Seul
Armes et Interventions
Groupe de participants / Bras |
Intervention / Traitement |
|---|---|
|
Expérimental: -10% of effective PMT
Patients are set to a voltage 10% less than their original PMT at start of study, Changes in PMT settings
|
The patients current motor threshold is determined and the patient is set to a new PMT (= new treatment arm)
|
|
Comparateur actif: former setting (+/- 0% of PMT)
Patients are set to their original PMT at start of study, Changes in PMT settings
|
The patients current motor threshold is determined and the patient is set to a new PMT (= new treatment arm)
|
|
Expérimental: +10% of effective PMT
Patients are set to a voltage 10% more than their original PMT at start of study, Changes in PMT settings
|
The patients current motor threshold is determined and the patient is set to a new PMT (= new treatment arm)
|
Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Délai |
|---|---|
|
Change in Pain measured on the Visual Analogue Scale with different PMT Settings
Délai: at the End of each trial period, typically 14 days after changes in PMT Settings
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at the End of each trial period, typically 14 days after changes in PMT Settings
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Mesures de résultats secondaires
Mesure des résultats |
Délai |
|---|---|
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Quality of Life assessment with the SF-36 questionnaire
Délai: at the end of each trial period, typically at 14 days
|
at the end of each trial period, typically at 14 days
|
Autres mesures de résultats
Mesure des résultats |
Délai |
|---|---|
|
Pain assessment with the McGill pain questionnaire to record impact of pain
Délai: at the end of each trial period, typically 14 days
|
at the end of each trial period, typically 14 days
|
Collaborateurs et enquêteurs
Parrainer
Publications et liens utiles
Publications générales
- Tsubokawa T, Katayama Y, Yamamoto T, Hirayama T, Koyama S. Chronic motor cortex stimulation for the treatment of central pain. Acta Neurochir Suppl (Wien). 1991;52:137-9. doi: 10.1007/978-3-7091-9160-6_37.
- Tsubokawa T, Katayama Y, Yamamoto T, Hirayama T, Koyama S. Treatment of thalamic pain by chronic motor cortex stimulation. Pacing Clin Electrophysiol. 1991 Jan;14(1):131-4. doi: 10.1111/j.1540-8159.1991.tb04058.x.
- Peyron R, Garcia-Larrea L, Deiber MP, Cinotti L, Convers P, Sindou M, Mauguiere F, Laurent B. Electrical stimulation of precentral cortical area in the treatment of central pain: electrophysiological and PET study. Pain. 1995 Sep;62(3):275-286. doi: 10.1016/0304-3959(94)00211-V.
- Lima MC, Fregni F. Motor cortex stimulation for chronic pain: systematic review and meta-analysis of the literature. Neurology. 2008 Jun 10;70(24):2329-37. doi: 10.1212/01.wnl.0000314649.38527.93.
Dates d'enregistrement des études
Dates principales de l'étude
Début de l'étude
Achèvement primaire (Réel)
Achèvement de l'étude (Réel)
Dates d'inscription aux études
Première soumission
Première soumission répondant aux critères de contrôle qualité
Première publication (Estimation)
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Estimation)
Dernière mise à jour soumise répondant aux critères de contrôle qualité
Dernière vérification
Plus d'information
Termes liés à cette étude
Termes MeSH pertinents supplémentaires
Autres numéros d'identification d'étude
- H14-01258
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