Chronic Pain & the Brain With Dr. Dave Hagedorn

brain 3d illustration

From the newest life taking its first gasp of air, to the labored breathing of someone passing into death—everyone, regardless of gender, race, or religion—feels pain. It is one of the most universally accepted experiences of living, and yet remains one of the most poorly understood.  

When pain becomes chronic and the bodily signs of trauma no longer appear to the naked eye, the burden itself is often presumed invisible—as if pain that exists on an emotional plane is disconnected from the body and is therefore not real. Why do we persist in discounting mental/emotional pain, when research on the brain shows, again and again, that traumatic experiences often pave a path for chronic pain?  

Over the last 10 years, advances in human neuroimaging have begun to identify the elements of the brain involved in the chronification of pain. Based on brain imaging studies, there is accruing evidence that chronic pain results from alterations in neural networks.1 A 2017 systematic review published in the European Journal of Pain found that maladaptive cognitive and emotional factors are associated with several brain regions involved in chronic pain.2 Dave Hagedorn, PhD, BCN, a leader in the field of non-invasive brain stimulation research, describes how emotional pain and physical pain are treated similarly in the brain:

“What we find most interesting is that people with emotional pain seem to have more posterior processing involving different areas in the brain than someone with nociceptive pain from something like a cervical injury, spinal cord injury, or femur break … something along those lines,” says Dr. Hagedorn. “This can help us then target their interpretation of that emotional pain. The brain really doesn’t care what pain type it is. If it’s an injury to the leg or even if they have a phantom limb, the brain still says it hurts. If you have emotional pain, the brain still says it hurts.

For us to have an empathic approach that embraces current neuroscience technology knowledge makes us better doctors and helps us be more compassionate and understanding of where the patient is coming from. Almost more importantly, it opens up our eyes and ears to new treatment options that help target the sources in the body that are causing people discomfort.

Dr. Hagedorn and other researchers who focus on treating traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) are embracing technologies that can visualize a patient’s neural activity to identify pathways for treatment. One of the founders of Evoke Neuroscience, Inc., a company that develops electrophysiology-based tools for cognitive development, Dr. Hagedorn has helped develop new “brain training” technologies to quickly and easily capture brain information. A computer measures electrical activity in the brain through an electroencephalogram (EEG) and interprets the signals. Cognitive, emotional, and stress states are captured, and the resulting patterns can be analyzed to identify dysfunctional networks, which are associated with chronic pain.3

In an interview with IFM Director of Medical Education Dan Lukaczer, ND, Dr. Hagedorn explains this process and how it helps patients experiencing chronic pain. Dr. Hagedorn is one of several expert speakers at IFM’s 2019 Annual International Conference on Stress, Pain, and Addiction.

Electrical Therapies for Chronic Pain

“There is a public health mandate and ethical obligation to study, develop, and deploy technologies and techniques that can lessen the burden of disease, injury, and illness.” – Dr. Dave Hagedorn  

In 2016, an estimated 50 million (or 20.4%) of US adults experienced chronic pain.4 Just 10 years prior to this study, 81.5% of primary care clinicians rated their undergraduate medical education in chronic pain as insufficient, with 54.7% rating their chronic pain training as residents as such.5 The 2006 study attributes the essential absence of undergraduate and resident education in chronic pain management to a finding that only 34% of physicians felt comfortable in managing patients with chronic pain and only 1% found doing so satisfying.5

Statistics show that people with chronic pain frequently seek complementary alternative treatments from their clinicians: 38% of American adults,6 16% of adults in the United Kingdom,7 41% of those with low back pain,8 and 44% of patients receiving opiates for chronic pain.9 Many states have added complementary/integrative treatments to Medicaid reimbursement as a response to this growing need. The Functional Medicine model, which underscores the profound power of the therapeutic partnership through the IFM Timeline and other tools, introduces clinicians to a variety of evidence-based modalities to address chronic pain.  

Learn more about chronic pain in military populations>

Current medical data also suggests that transcranial magnetic stimulation has the potential to be an effective, complementary treatment modality for patients with chronic neuropathic pain syndromes.1 Dr. Hagedorn uses this therapy with chronic pain patients in his practice. Additionally, acupuncture, muscle biofeedback, and sleep training help his patients develop healthy coping strategies. Research on non-pharmacological therapies is growing; some highlights in the literature, connecting chronic pain to the brain, include:

  • Transcutaneous electrical nerve stimulation: Transcutaneous electrical nerve stimulation (TENS) is another noninvasive, inexpensive, and safe analgesic technique used for relieving acute and chronic pain.10 A 2018 study was the first of its kind to investigate the effect of high-frequency TENS on gamma band activity—a kind of brain wave that consists of very rapid oscillations and plays an important role in pain perception as well as pain processing. In this study, EEG analysis revealed significant enhancement of gamma total power after inducing pain as compared to baseline. Gamma, like other brain rhythms, can provide a signature of cognitive state, as well as network dysfunction. The results demonstrated that the high-frequency TENS could reduce the enhanced gamma band activity after inducing tonic pain in healthy volunteers, a finding that might help as a functional brain biomarker that could be used for pain treatment.10
  • Volitional neural modulation: Volitional neural modulation using neurofeedback has been indicated as a potential treatment for chronic conditions that involve peripheral and central neural dysregulation.11 A 2019 study utilized neurofeedback (a form of biofeedback in which subjects respond to a display of their own brainwaves or other electrical activity of the nervous system) in patients suffering from fibromyalgia. Researchers found that neurofeedback training induced a delayed reduction in the patient’s subjective symptom of chronic pain. “This indirect approach to chronic pain management reflects the substantial link between somatic and affective dysregulation that can be successfully targeted using neurofeedback,” report the authors.11
  • Transcranial Alternating Current Stimulation: Transcranial alternating current stimulation (tACS) is a new non-invasive treatment strategy that was studied in 2019 for the first time in chronic pain.3 A randomized, crossover, double-blind, sham-controlled study in patients with chronic low back pain investigated how alpha oscillations relate to pain symptoms for target identification and whether tACS could engage this target and thereby induce pain relief. Stimulation with alpha-tACS compared to sham stimulation significantly enhanced alpha oscillations in the somatosensory region and was correlated with pain relief.3 “The exciting thing is that these results occurred after just one session,” said co-first author Julianna Prim, PT, PhD, in the Department of Allied Health Sciences at the UNC School of Medicine. “We hope to conduct a larger study to discover the effects of multiple tACS sessions over a longer time period … Ultimately, if we want to develop better treatments, cures, and prevention strategies, then these sorts of new approaches that bring researchers together are of fundamental importance.”12
  • Flexyx Neurotherapy System: Recently, a novel form of brainwave-based intervention known as the Flexyx Neurotherapy System (FNS) that involves minute pulses of electromagnetic energy stimulation of brainwave activity has been suggested as a means to address symptoms of TBI.13 Nine veterans of the wars in Afghanistan and Iraq with moderate to severe chronic headaches following service—connected to TBI and complicated by posttraumatic stress symptoms—were treated in 20 individual FNS sessions at the Brain Wellness and Biofeedback Center of Washington, Bethesda, Maryland. Progressive declines in symptom scores were generally observed in patients receiving FNS. Highly significant reductions in headache pain were in evidence by the end of treatment for both the worst and average headache ratings, decreasing from moderate/severe levels to generally only mild levels.13

“The more we harness proven technologies and use them synergistically, the better outcomes we will have and the less likelihood there will be that a patient is going to become addicted to narcotics,” says Dr. Hagedorn.

[Functional Medicine] also teaches clinicians that, just like in medical school 101, you have to take a good clinical history. No technology replaces a competent physician’s clinical history and careful thought. – Dr. Hagedorn

The individualized, patient-centered, science-based approach that Dr. Hagedorn speaks of underlies the Functional Medicine model. Functional Medicine recognizes the power and impact of emotional, mental, and spiritual life on physical health and evaluates each component, seeking to ultimately bring them all into balance. In the future, with standardization and validation, brain imaging could provide objective biomarkers of chronic pain and guide treatment for personalized pain management. When combined with a therapeutic, empathetic partnership between patient and clinician, healing can begin.  

“We, [as clinicians], should never assume we have all the answers,” says Dr. Hagedorn. “It excites me to search for more information, collaborate with other practitioners, and talk to other experts in the field. It requires a patient approach—being fully committed to improving a person’s sense of wholeness so they feel cared for.

The goal is to reawaken hope and belief in the possibility of total wellness.


  1. Young NA, Sharma M, Deogaonkar M. Transcranial magnetic stimulation for chronic pain. Neurosurg Clin N Am. 2014;24(4):819-832. doi:10.1016/
  2. Malfliet A, Coppieters I, Van Wilgen P, et al. Brain changes associated with cognitive and emotional factors in chronic pain: a systematic review. Eur J Pain. 2017;21(5):769-786. doi:10.1002/ejp.1003
  3. Ahn S, Prim JH, Alexander ML, McCulloch KL, Fröhlich F. Identifying and engaging neuronal oscillations by transcranial alternating current stimulation in patients with chronic low back pain: a randomized, crossover, double-blind, sham-controlled pilot study. J Pain. 2019;20(3):277.e1-277.e11. doi:10.1016/j.jpain.2018.09.004
  4. Dahlhamer J, Lucas J, Zelaya, C, et al. Prevalence of chronic pain and high-impact chronic pain among adults — United States, 2016. MMWR Morb Mortal Wkly Rep. 2018;67(36):1001–1006. doi:10.15585/mmwr.mm6736a2
  5. Yanni LM, McKinney-Ketchum JL, Harrington SB, et al. Preparation, confidence, and attitudes about chronic noncancer pain in graduate medical education. J Grad Med Educ. 2010;2(2):260-268. doi:10.4300/JGME-D-10-00006.1
  6. Nahin RL, Barnes PM, Stussman BJ, Bloom B. Costs of complementary and alternative medicine (CAM) and frequency of visits to CAM practitioners: United States, 2007. Natl Health Stat Report. 2009;(18):1-14.
  7. University of Bristol. More adults using complementary and alternative medicine in England but access is unequal. Published November 13, 2018. Accessed March 28, 2019.
  8. Ghildayal N, Johnson PJ, Evans RL, Kreitzer MJ. Complementary and alternative medicine use in the US adult low back pain population. Glob Adv Health Med. 2016;5(1):69-78. doi:10.7453/gahmj.2015.104
  9. Fleming S, Rabago DP, Mundt MP, Fleming MF. CAM therapies among primary care patients using opioid therapy for chronic pain. BMC Complement Altern Med. 2007;7:15. doi:10.1186/1472-6882-7-15
  10. Ebrahimian M, Razeghi M, Zamani A, Bagheri Z, Rastegar K, Motealleh A. Does high frequency transcutaneous electrical nerve stimulation (TENS) affect EEG gamma band activity? J Biomed Phys Eng. 2018;8(3):271-280.
  11. Goldway N, Ablin J, Lubin O, et al. Volitional limbic neuromodulation exerts a beneficial clinical effect on fibromyalgia. Neuroimage. 2019;186:758-770. doi:10.1016/j.neuroimage.2018.11.001
  12. University of North Carolina Health Care. Can stimulating the brain treat chronic pain? Science Daily. Published November 8, 2018. Accessed March 28, 2019.
  13. Nelson DV, Esty ML. Neurotherapy for chronic headache following traumatic brain injury. Mil Med Res. 2015;2:22. doi:10.1186/s40779-015-0049-y

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