Effectiveness of Transcranial Direct Current Stimulation in Chronic Pain Related to Lumbar Spinal Stenosis

Inclusion Criteria: * Magnetic resonance imaging evidence of narrowing of the central canal, lateral recess, and/or foramen. * Persistent leg pain for at least 3 months * An average pain intensity score (during walking) of at least 4 out of 10 on the Visual Analog Scale at screening and randomisation * Persistent neurogenic claudication for at least 3 months * stable pharmacological treatment for pain and sleep disorders for at least 1 month before the study and throughout the trial * If present, coexisting low back pain intensity should be less than leg pain intensity. Exclusion Criteria: * Patients with other neurological or psychiatric disorders including ongoing major depression (Beck Depression Score\>14) * Uncontrolled/unstable endocrinologic, cardiovascular, pulmonary, hematologic, hepatic, renal disease * Inflammatory diseases, cancer * Severe hip and/or knee osteoarthritis that affects Treadmill Walking Test * Absolute/relative contraindications of tDCS (past head trauma resulting with loss of consciousness, epilepsy, past neurosurgical intervention, intracranial hypertension, implanted devices, migraine, chronic-severe headache episodes, a history of side effects with non-invasive brain stimulation techniques, skin diseases, pregnancy)