The goal of this study is to investigate the role of central neural pathways in mediating chronic pain. The aim of the study is to test the effect of stimulating brain regions that are part of a network underlying central pain processing using a non-invasive brain stimulation technique, transcranial Direct Current Stimulation (tDCS). Prior studies have used tDCS to target both sensory related cortical areas and those important for higher-order representations of pain. This study will target brain regions important for the behavioral response to the chronic sensation of pain. The hypothesis is that stimulation of these brain regions can modulate not only the affective component of pain, but ultimately also improve functioning and quality of life. This hypothesis will be tested by treating study participants eighteen and older with chronic low back pain (CLBP) of greater than six months using tDCS. To be part of this study, participants must meet all the inclusion and exclusion criteria.

Inclusion Criteria:

• Chronic Low Back Pain ≥ 6 months duration in the lumbar region, present more than half the days of the month, and on average be at a moderate level of severity in the last month
• At least one trial of physician recommended medication (e.g. acetaminophen, NSAIDS, skeletal muscle relaxants)
• Pre-existing opioid and non-opioid pain medication must be non-existent or stable (medications have not changed for one month)
• Be able to understand, read and write English
• If female and of childbearing age, agree to use acceptable birth control during the study treatment period (oral contraceptives, history of tubal ligation, history of a hysterectomy, or a reliable barrier method)

Exclusion Criteria:

• Lifetime Diagnostic and Statistical Manual (DSM) IV diagnosis of bipolar disorder, schizophrenia, or other chronic psychotic condition
• Current DSM-IV diagnosis of substance dependence for alcohol, sedative/hypnotic drugs, stimulants, cocaine
• Current cancer, infection, or inflammatory arthritis
• Broken skin or other lesions in the area of the electrodes
• Uncontrolled medical problems, such as diabetes mellitus, hypertension, pulmonary or airway disease, heart failure, coronary artery disease, or any other condition that poses a risk for the subject during participation
• Presence of metal in the cranial cavity
• Holes in the skull made by trauma or surgery
• Pacemakers, medication pumps, and other implanted electronic hardware
• Pregnancy

The data collected from the 21 participants who completed tDCS treatment (either active or sham) is included in the analysis.

8 weeks

small sample (N=21), participants not stratified by premorbid anxiety levels, inability to guarantee optimal targeting of left dorsal anterior cingulate cortex (dACC) in all participants, inability to address laterality effects of pain perception