An Update on Repetitive Transcranial Magnetic Stimulation for the Treatment of Co-morbid Pain and Depressive Symptoms

Abstract

Recent meta-analyses have included both pain and depression outcomes in fibromyalgia and chronic pain. Randomized controlled trials have also been conducted in post-herpetic neuralgia, trauma-related headache, and neuropathic pain with attention to both pain and depressive symptoms. In general, studies have demonstrated reduction in pain in patients with fibromyalgia as an add-on treatment, post-herpetic neuralgia, trauma-related headache, and neuropathic pain. There are variable findings for reduction in depressive symptoms in patients with co-morbid pain disorders. Theta burst stimulation (TBS) is a novel rTMS protocol that has recently been investigated in patients with depression and some smaller trials in patients with co-morbid pain disorders. These emerging treatment options may have similar or greater therapeutic potency and may be delivered with greater efficiency. There is evidence to support the use of rTMS for its analgesic effects in various pain syndromes. The variable results between trials for treatment of concurrent depressive symptoms may be due to heterogeneity in treatment protocols including parameters such as site of stimulation (primary motor cortex versus dorsolateral prefrontal cortex) and restrictions in the patient population which usually exclude primary psychiatric diagnoses. Future trials should work to standardize these protocols, investigate novel protocols like TBS, and continue to include standardized assessment of concurrent psychiatric outcomes such as depression and anxiety.

Chronic Pain: Structural and Functional Changes in Brain Structures and Associated Negative Affective States

“…Additionally, rTMS is thought to exert antinociceptive effects by altering neuronal activity in the PAG matter related to pain processing. rTMS also influences the endogenous opioid system, which can control chronic pain [126,127].…”

Transcranial Magnetic Stimulation for Pain, Headache, and Comorbid Depression: INS-NANS Expert Consensus Panel Review and Recommendation

“…There is evidence that stimulating DLPFC relieves pain as well as depression (94,138,139). In contrast to motor targets, the most effective DLPFC targets in depression are less well established in part because there is not an analog to the motor hot spot for nonmotor targets (other than the occipital phosphenes) in which stimulation has a clear behavioral response signifying accuracy.…”

Using Functional Near-Infrared Spectroscopy to Study the Effect of Repetitive Transcranial Magnetic Stimulation in Concussion: A Two-Patient Case Study

“…A number of studies report that chronic headache, depression, and mTBI are associated with alterations in prefrontal brain areas, characterized by reduced gray matter volume and/or cortical thickness, changes in frontal white matter microstructure, as well as altered function in studies of task-response and functional connectivity (36–44). Interestingly, many studies report functional and behavioral improvements following prefrontal rTMS treatment in patients with these disorders (14, 15, 34, 35, 45–49). This has led to the hypothesis that rTMS to the prefrontal cortex can alter its function and microstructure, and result in improved outcomes in patients with PPCS.…”