Transcranial Stimulation for Physiotherapy Optimisation - Chronic Low Back Pain (STOP-CLBP)

The main objective of this study is to investigate the effects of non-invasive brain stimulation (the so-called transcranial direct current stimulation ; tDCS) combined with an active physiotherapy program on the multidimensional impact of pain in patients with Chronic Low Back Pain (CLBP).The secondary objectives are to compare the effects of these interventions on fear of movement, psycho-emotional state, function, functional connectivity of the left dorsolaterla prefrontal cortex (DLPFC) and erector spinae activity.Participants will perform:2 sessions including clinical assessments including questionnaires, brain activity assessment (with EEG), and back muscle activity assessment (with EMG)9 interventional sessions of active physiotherapy combined with active or sham tDCS during 3 weeks (3 per week).Investigators will compare active tDCS with sham tDCS (non active) to evaluate if active tDCS is more effective than sham tDCS.

Inclusion Criteria:ability to give informed consent,ability to follow protocol instructions,diagnosis of Non Specific Chronic Low Back Pain ≥12 weeks,low back pain with or without radiation to the knee,average pain of the previous week ≥ 3 on the VAS (Visual Analogue Scale).have sufficient cognitive ability to fill in the various questionnaires (Level B2 French),Exclusion Criteria:herniectomy within the last 6 months,lumbar spinal surgery with material (e.g. prosthesis, spondylodesis),sensory or motor deficit of a lower limb,radiant pain in the lower limb beyond the knee,neuropathic pain (according to the dn4 questionnaire),diagnosis of an inflammatory rheumatic disease (e.g. rheumatoid arthritis, spondyloarthropathy),diagnosis of a chronic generalized pain syndromee of fibromyalgia,pregnancy,presence of neurological or neuropsychiatric disorders,have epilepsy or a recent or severe head injury,metal implant in the skull (excluding fillings),presence of a pacemaker,unhealed wound or skin disease on the skull (electrode contact area)