Transcranial Direct Current Stimulation (tDCS) Combined With Aerobic Exercise in Chronic Nonspecific Low Back Pain (LBP)

The goal of this clinical trial is to learn about the effects of transcranial direct current stimulation (tDCS) combined with aerobic exercise in non-specific low back pain patients. The main question aims to answer: • Which are the effects of tDCS treatment combined with aerobic exercise compared to Sham tDCS combined with aerobic exercise in non-specific Low Back Pain? Participants will be asked to complete questionnaires and they will receive treatments as tDCS or Sham tDCS and aerobic exercise (treadmill walking). Researchers will compare a group who is treated with a combination of tDCS and aerobic exercise versus a group receiving placebo tDCS and aerobic exercise to see the effects on pain intensity, pressure pain, disability, kinesiophobia, quality of life, catastrophism, Heart Rate Variability and cortical excitation.

Low back pain (LBP) is the main cause of disability worldwide with a prevalence of 70 to 85% of the population. Chronic LBP (CLBP) is defined as a pain lasting more than 12 weeks. CLBP does not have peripheral nociceptive stimuli, but it is characterized by the presence of a chronic change in neuroplasticity. Transcranial direct current stimulation (tDCS) is a type of therapeutic intervention that can modulate the cortical excitability of a wide neural network involved in the elaboration of pain, resulting in an efficacy option for CLBP treatment. Aerobic exercise represents another typology of effective therapeutic intervention in the treatment of pain intensity and disability related to CLBP.

The main objective of the study is to determine the efficacy of tDCS combined with aerobic exercise compared to shame/placebo tDCS combined with aerobic exercise in middle-aged subjects with non-specific CLBP in the short, medium and long term.

Methods: In a double-blinded pilot randomized controlled trial, 38 subjects aged between 18 and 65 years, with a diagnose of non-specific LBP for 3 months, a Visual Analogue Scale (VAS) result of \>20mm and a Roland-Morris Scale result of \>4 will be selected for the following study. Participants will be divided in two groups of 19 subjects each one: experimental group A (20 minutes of tDCS at 2 mili Amper + 20-30 minutes of aerobic exercise at 60-80% of HRmax) and controlled group B (30 seconds of sham/placebo tDCS at 2milli amperes + 20-30 minutes of aerobic exercise at 60-80% of maximum heart rate). The following outcomes will be measured: pain intensity (100mm VAS), pressure pain (pressure algometer), disability (Roland-Morris questionnaire), kinesiophobia (Tampa Scale for kinesiophobia), quality of life (SF-12 health questionnaire), catastrophism (Pain Catastrophizing Scale), Heart Rate Variability ( Polar Team) and cortical excitation (Critical Flicker Fusion).

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of non-specific Low Back Pain for at least 3 months based on careful radiological evaluation and clinical diagnosis by a physician.
* Aged from 18 till 65 years old.
* Scoring higher than 20mm on the 100 mm VAS scale
* Scoring higher than 4 on the Rolland-Morris scale

Exclusion Criteria:

Any subject presenting at least one of the following exclusion criteria will be excluded from the study:

* Vertebral fractures, osteoporosis
* Infections
* Lumbar surgical, herniated disc or nerve root compression
* Rheumatologic diseases
* People with central nervous system alterations
* Structured deformities of the spine (scoliosis)
* Oncology patients in active treatment or within 5 years after the end of the treatment
* Fibromyalgia
* Women who are pregnant or who may be pregnant
* Contraindications to tDCS (epilepsy, cranial implanted devices, neurological o psychiatric disorders, sever cardiopulmonary, renal or hepatic disorders)
* Being under physiotherapeutic or osteopathic treatment during the study period
* Absolute contraindications to aerobic exercise (acute myocardial infarction, unstable angina pectoris, uncontrolled arrhythmia, heart failure, acute pulmonary embolism, myocarditis or acute pericarditis)
* People who need walking assistance (cane, other person to assist)
* Patients who practise regular physical activity defined as leisure-time physical activity for 30 minutes, three or more times per week
* People unable to give informed consent, or unable to complete the selected questionnaires.