Neuromodulation of Lidocaine Cream Effect on Chronic Pain Patients

Study Overview
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Brief Summary
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Chronic low back pain patients aged 21 to 60 needed for a research study of the effects of transcranial direct current stimulation (tDCS) on the analgesic effects of lidocaine cream as measured by functional Magnetic Resonance Imaging (fMRI). Study will be conducted on nine separate days not requiring an overnight stay in the hospital.

Official Title
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Neuromodulation of Lidocaine Cream Effect on Chronic Pain Patients

Conditions
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Chronic Low Back Pain

Intervention / Treatment
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* Device: tDCS
* Other: Lidocaine cream
* Other: Control cream


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Volunteers 21-60 years of age. Meets the Classification Criteria of chronic LBP (having low back pain for more than 6 months), as determined by the referring physician. At least 4/10 clinical pain on the 11-point LBP VAS (criteria recommended by Dworkin et al.) At least a 10th grade English-reading level; English can be a second language provided that the patients understand all questions used in the assessment measures. Exclusion Criteria: Specific causes of back pain (e.g., cancer, fractures, spinal stenosis, infections). Complicated back problems (e.g., prior back surgery, medicolegal issues). The intent to undergo surgery during the time of involvement in the study. History of cardiac, respiratory, or nervous system disease that, in the investigator's judgment, precludes participation in the study because of a heightened potential for adverse outcome. For example: asthma, claustrophobia, epilepsy or acute eczema under the electrodes. Presence of any contraindications to MRI scanning. For example: cardiac pacemaker, metal implants, claustrophobia, pregnancy, cannot lie still in an fMRI scanner. History of medical or psychiatric illness. History of substance / alcohol abuse or dependence.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 60 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: real tDCS<br>In this group, the tDCS stimulates areas of the brain being examined in this study to increase their activity. | Device: tDCS<br>* Electrical stimulation will be applied on the head to temporarily influence brain activity in specific regions.<br>Other: Lidocaine cream<br>* Lidocaine cream will be applied to reduce pain sensitivity (analgesia).<br>Other: Control cream<br>* A neutral cream will be applied as a control.<br>|
| Sham Comparator: sham tDCS<br>In this group, sham tDCS does not provide real stimulation though participants will not know this until the debriefing at the end of the study. Sham will be used to determine if the results of this study are due to the tDCS or other reasons. | Device: tDCS<br>* Electrical stimulation will be applied on the head to temporarily influence brain activity in specific regions.<br>Other: Lidocaine cream<br>* Lidocaine cream will be applied to reduce pain sensitivity (analgesia).<br>Other: Control cream<br>* A neutral cream will be applied as a control.<br>|
| Other: control group<br>In this group, participants will receive tDCS but will only receive a cream on their lower back. | Device: tDCS<br>* Electrical stimulation will be applied on the head to temporarily influence brain activity in specific regions.<br>Other: Lidocaine cream<br>* Lidocaine cream will be applied to reduce pain sensitivity (analgesia).<br>Other: Control cream<br>* A neutral cream will be applied as a control.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fMRI signal changes |  | 2 days; Sessions 5 and 7 | 
| Gracely Scale pain rating changes |  | 2 days; Sessions 2 and 7 | 
| resting state functional connectivity changes |  | 2 days; Sessions 5 and 7 |