A great number of people suffer from lower back pain. The pain can begin at any age with peak onset occurring during adolescence or around age 45. A team of researchers from the University of North Carolina recently published a study that could prove promising in the treatment of this form of chronic pain without the need for drugs. What if targeted brain stimulation could relieve chronic back pain?

Several studies have shown that chronic pain is the leading cause of disability worldwide. According to the authors of the present study, by focusing on the peripheral causes of pain, most of these studies have overlooked the role played by brain activity in the disease. F. Fröhlich, the article’s main author, thinks (like other researchers) that, over the long term, the presence of pain could have a negative influence on the organization of communication between nervous system cells, including neural networks. This theory suggests that neural networks may become bogged down in a sort of "neural rut," leading to chronic pain. Recent studies on this maladaptive reorganization of the central nervous system in cases of disease have shown that the oscillations of the neural network in the thalamocortical system may play a major role in the pathophysiology of chronic pain (this discipline of biology looks at the physical, cellular, and biochemical systems that lead to the onset of a disease). There are several types of brain waves that vary according to brain area and activity (e.g. talking, eating, etc.).

The research team led by F. Fröhlich (Associate Professor of Psychiatry and Director of the Center for Neurostimulation at the University of North Carolina) was particularly interested in alpha oscillations. Alpha oscillations occur when we are in a "calm" state of consciousness. The scientists hypothesized that a lack of these oscillations in the somatosensory cortex could be a cause of chronic pain. Improving these waves through transcranial AC stimulation (TACS) could thus help relieve the pain. To test this hypothesis, the scientists recruited 20 patients suffering from chronic lower back pain. A network of electrodes was attached to each subject’s head and they then participated in two sessions of TACS (length = 40 minutes) at an interval of one to three weeks. During one of the sessions, the stimulations targeted the somatosensory cortex to enhance natural alpha waves. A “simulated” session was organized so that participants could not tell the difference between the TACS and placebo sessions.

To measure the alpha waves, the researchers used high density electroencephalography. In comparison to the sham stimulation, they found that TACS significantly increased alpha oscillations in the somatosensory area, and they were able to correlate this increase with pain relief. Indeed, patients reported no pain after TACS sessions (on a subjective scale of 1 to 10).

The results of this pilot study are very encouraging and the authors are eager to carry out a broader study to investigate the effects of several sessions of TACS over a longer period of time.