This clinical investigation aims to evaluate the efficacy and safety of a home-based device providing electrical stimulation of the brain named transcranial direct current stimulation (tDCS ) , in patients with chronic pain who have been transiently relieved by repetitive transcranial magnetic stimulation delivered at hospital (less than one month benefit). The general objective is to show that these patients may best benefit from home based tDCS while rTMS performed in hospital has only limited and transient efficacy. Each participant will be randomized into one of two arms to receive during 3 months either active tDCS or sham tDCS. Neither the investigator nor the patient will be aware of the treatment. The efficacy will be assessed on pain intensity (primary outcome at 3 months) and several secondary outcomes (qualify of life, pain symptoms , global impression of change, pain relief, sleep, anxiety, depression) every month for up to 3 months. Safety will be assessed at each follow up visit for up to 3 months. The participants will be asked to self stimulate themselves with the device 5 days per week for about 20 minutes.
This will be a randomised, double-blind, parallel-group, bi-centric study versus placebo stimulation. Patients undergoing previous treatment with rTMS of the motor cortex in routine in our pain center and with at least 30 % pain relief with rTMS (after 10 sessions) but only transient pain relief (less than one month) will stop their treatment for at least one month. They will then be randomised to receive one of the 2 treatments under study (active tDCS of the motor cortex, placebo tDCS of the motor cortex, TENS eco plus). The protocol will involve a 20-minute tDCS session (2 mA) at home, 5 days a week for 12 weeks. The treatment will continue for 12 weeks and the final evaluation will take place at 12 weeks. TENS ECO PLUS is a portable transcranial direct current stimulation (tDCS) system (tDCS kit) supplied by the Monath Electronic laboratory, designed for use at home; this system will first be tested in hospital during a test session with explanations to the patient on how to use it. The stimulation intensity is blocked above a certain threshold by the system to avoid any risk of epileptic seizure. Sham or placebo stimulation uses the same medical device without active stimulation. Given the exploratory nature of the trial and in order to reduce study participant's exposure to a potentially useless treatment, blinded interim analysis will be conducted dring the course of the trial in the first 40 enrolled patients and the study will be stopped early if this analysis suggests large differences between the two treatment groups or conversely shows obvious futility.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
70
Home-delivered tDCS device
Centre d'Evaluation et de Traitement de la douleur, INSERM U 987
Boulogne-Billancourt, Hauts de Seine, France
RECRUITINGSelf reported pain intensity in a diary
Weekly average of the last 7 numerical pain scores (from 0 no pain to 10 maximal pain imaginable) recorded every day by the patient at the end of the treatment as compared to baseline values
Time frame: Baseline and 12 weeks
Effects on self reported pain intensity over the course of the study
Weekly averaged pain intensity on numerical pain scales (0-10, with 0 no pain and 10 maximal pain imaginable) self reported on pain diary over the course of the study
Time frame: over the course of the study from baseline to week 12
EQ-5D-5L (EuroQol)
Quality of life on EQ-5D-5L scale including 5 levels of perceived problems each rated on 0-3 categorical scales
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
Brief Pain Inventory
Average pain on numerical pain scales (from O no pain to 10 maximal pain) on the Brief Pain Inventory (BPI)
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
Neuropathic Pain Symptom Inventory (NPSI)
Self reported neuropathic pain questionnaire to assess 5 neuropathic dimensions rated on the same numerical rating scales (from 0 no symptom to 10 maximal symptom). This questionnaire will be proposed only for neuropathic patients.
Time frame: Baseline, then week 1, week 4, week 8 and week 12 after the treatment
Fibromyalgia Impact Questionnaire (FIQ)
Self reported questionnaire assessing the impact of fibromyalgia on everyday life. This questionnaire will only be proposed to patients with fibromyalgia.
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
Hospital anxiety and depression scale (HADS)
Symptoms of anxiety rated on 21 on the HADS with 0 indicating no anxiety and 21 indicating the maximal level of anxiety
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
Medical outcomes study sleep scale (MOS sleep)
Sleep impairement on the MOS sleep allowing to calculate two indexes (sleep problem index 6 and 9)
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
McGill pain questionnaire short form (SF-MPQ)
SF-MPQ (Melzack et al 1986) allowing to evaluate the sensory and affective dimension of pain; the sensory dimension of pain is rated on 30 with 30 indicating more severe sensory dimension of pain
Time frame: Baseline, then week 1 (± 3 days), week 4, week 8 and week 12
Pain Catastrophizing Scale (PCS)
Pain catastrophizing on the PCS (Sullivan et al), scored from 0 to 52 (with 52 indicating worse catastrophizing)
Time frame: Baseline then 1 week ± 3 days then 4 weeks, 8 weeks and 12 weeks
Patient global impression of change (PGIC)
PGIC as assessed on a 7 category scale from much improved to much deteriorated
Time frame: Baseline then 4 weeks, 8 weeks and 12 weeks
Treatment-emergent adverse effects of home delivered tDCS
Treatment emergent adverse effects will be assessed at each follow up visit by the investigators. Patients will also report any adverse effect occurring immediately after each session of tDCS or between sessions on a self diary.
Time frame: Every day over the course of the study and at each follow up visit, at days 3 (initial follow up safety visit) then days 10, week 4, week 8 and week 12
Categorical pain scale
Categorical pain scale (from no pain to very severe pain)
Time frame: Baseline then 10 days (± 3 days), 4, 8 and 12 weeks
Blinding assessment
A blinding assessment as used in our prior studies will be proposed to every patient including 2 questions : what treatment they think they had received (active or placebo) ; the main reason for their choice (efficacy, side effects, both, other reasons)
Time frame: 12 weeks
Satisfaction with the treatment
Satisfaction with the treatment will be assessed on a 0 to 10 numerical scale (0 = not satisfied ; 10 : extremely satisfied)
Time frame: 12 weeks
Interference score of the Brief Pain Inventory
Interference score rated from 0 to 70 from the Brief Pain Inventory
Time frame: Baseline then 1 week, 4 weeks, 8 weeks and 12 weeks after the treatment
Pain as its least from the Brief Pain Inventory
Pain intensity as its least over the past 24 hours rated on a numerical rating scale from 0 to 10
Time frame: Baseline then 1 week, 4 weeks, 8 weeks and 12 weeks after the treatment
Pain as its worst from the Brief Pain Inventory
Pain intensity as its worst over the past 24 hours rated on a 0-10 numerical rating scale
Time frame: Baseline then 1 week, 4 weeks, 8 weeks and 12 weeks
Clinician global impression of change (CGIC)
7 category Clinician based global impression of change from severe deterioration to significant improvement
Time frame: Baseline and at 12 weeks
EQ5D -5L Euroqol Visual analog scale
Visual analog scale rated from 0 to 100 to measure health status with 0 being the worse health status and 100 being the best possible health status
Time frame: Baseline, week. 1, weeks 4, weeks 8 and weeks 12 after the treatment
Symptoms of depression on the Hospital Anxiety and Depression Scale (HADS)
Symptoms of depression rated on 21 on the HADS with 0 indicating no anxiety and 21 indicating the maximal level of depression
Time frame: Baseline then one week, 4 weeks, 8 weeks and 12 weeks
Short Form McGill Pain Questionnaire SF-MPQ
SF-MPQ allowing to evaluate the affective dimension of pain; the affective dimension of pain is rated from 0 to 12 with 12 indicating more severe sensory dimension of pain
Time frame: Baselinen one week, 4 weeks, 8 weeks and 12 weeks after the treatment
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