Cyclization of Motor Cortex Stimulation

Study Overview
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Brief Summary
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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 timing parameters in patients already implanted with MCS and have received good pain relief. The investigators wish to cyclize on/off MCS in order to save the battery life of the stimulator and also decrease stimulus habituation. The investigators hope to determine these timing parameters while maintaining optimal pain relief.

Official Title
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The Relationship Between Cyclizing Stimulation and Effective Stimulation During Motor Cortex Stimulation

Conditions
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Neuropathic Pain

Intervention / Treatment
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* Device: motor cortex stimulation (Change of Stimulation Timing)


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Original Setting- MCS 30 min off/0 min off<br>Patients at baseline with their original MCS settings: on 30 minutes, off 0 minutes in any single half-hour. | Device: motor cortex stimulation (Change of Stimulation Timing)<br> <br> |
| Experimental: MCS 25 min on/5 min off<br>Patient MCS settings programmed to: on 25 minutes, off 5 minutes in any single half-hour. | Device: motor cortex stimulation (Change of Stimulation Timing)<br> <br> |
| Experimental: MCS 20 min on/10 min off<br>Patient MCS settings programmed to: on 20 minutes, off 10 minutes in any single half-hour. | Device: motor cortex stimulation (Change of Stimulation Timing)<br> <br> |
| Experimental: MCS 15 min on/15 min off<br>Patient MCS settings programmed to: on 15 minutes, off 15 minutes in any single hour. | Device: motor cortex stimulation (Change of Stimulation Timing)<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Pain measured on the Visual Analogue Scale (VAS) with different stimulation settings |  | At the End of each trial period, typically 14 days after change in stimulation settings | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quality of Life assessment with the SF-36 questionnaire |  | At the end of each trial period, typically at 14 days after change in stimulation settings |