rTMS: Filling the Gaps in the Broken Nervous System

Over the last decade, transcranial magnetic stimulation (TMS) has evolved from a prospective scientific tool to a revolutionary force in clinical application. TMS is a unique method which uses non-invasive magnetic fields to stimulate and modulate brain connectivity for a desired behavioral change. During a repetitive transcranial magnetic stimulation (rTMS) therapy session, an electromagnetic coil is placed above the desired area of the brain, repetitively delivering magnetic pulses to fire action potentials in certain neural networks. Regardless of its indisputable effects on improving the lives of patients with conditions such as depression, AUD, TBI, etc. the replicability of TMS varies from person to person due to its heterogeneous physiological effects. While this is true, the realm of rTMS therapy has become a multi-disciplinary investigation, with scientists applying the methods to varying neurological conditions in hopes of improved outcomes. 

Although new and innovative techniques have emerged, TMS has shown the most promise in regard to bettering impaired mental states. Traumatic brain injury (TBI) and spinal cord injury (SCI) are life-altering conditions resulting from trauma to the central nervous system. Both conditions prove to be an emotional, physical, and economic burden on patients, families, and communities. The preventative nature of TBI and SCI have become increasingly recognized, making the two a health priority across the globe. In Dr. Amy Harrold’s study “Transcranial magnetic stimulation: potential treatment for co-occurring alcohol, traumatic brain injury, and post-traumatic stress disorders”, Dr. Herrold and her colleagues explored the application of rTMS on AUD, mTBI, and PTSD individually and as co-occurring counterparts on U.S. veterans (deployed to Iraq and Afghanistan) with post-trauma conflicts at the VA. Using rTMS treatments, her results illuminated reduced cravings in patients with AUD and reduced medication usage for individuals with PTSD. While the relation between PTSD, mTBI, and AUD are unknown, her findings showed significant improvements in the parameters of the altered brain regions targeted with rTMS. By provoking inhibitory and excitatory responses in the neural networks effected, she was able to modulate neuronal activity for a bettered outcome.  Amy Herrold wants to further her study by investigating the connectivities of these co-occurring conditions and the manners in which rTMS alters such pathways individually and as a unit. 

Through my off-campus research at Shirley Ryan AbilityLab, under Dr. Monica Perez, I have been able to first-handedly apply and observe rTMS treatments on individuals with spinal cord injury. In her 2017 journal article, “A novel cortical target to enhance hand motor output in humans with spinal cord injury”, she explains her project in depth. Analyzing individuals with incomplete SCIs, Perez and her colleagues provide the first evidence of cortical target sites in improving motor function in paraplegics and quadriplegics. Her study focuses on rehabilitation and enhancement of residual sensorimotor pathways in individuals with SCI by using rTMS to elicit corticospinal plasticity. Through 180 pairs of TMS on the motor cortex, Perez measures evoked motor potentials before and after a 10-week rTMS treatment. In her study, she pairs rTMS with motor function exercises focusing on grasp, dexterity, and pinch for the upper limbs as well as walking and biking training for lower limb regeneration. Her findings show the first evidence of improving refined motor function in humans with SCI through non-invasive corticospinal stimulation using rTMS.

Instead of using rTMS on co-occurring AUD, PTSD, and mTBI, Perez focuses on using the treatment toward rehabilitation strategies in SCI patients. In both studies, rTMS proved to be beneficial to their studies respectively. Yet, with neuroscience, questions remain. Some questions pertaining to TMS include if paired strengthening exercises and activities induce changed responses in individuals, the physiology of varying neural tracts and how they concur, and the uniformity of the treatment across varying individuals and injuries. Though these exist, the illustration of the various applications of rTMS different neurological disorders by both Dr. Harrold’s and Dr. Perez’s project show promise for treating and healing global health burdens, forever changing the waves of neurological treatment.

Works Cited

Herrold, Amy, et al. "Transcranial magnetic stimulation: potential treatment for co-occuring alcohol, traumatic brain injury, and post-traumatic stress disorders", Neural Regeneration Research, 11 Nov. 2019

Federico, Paolo, and Monica A. Perez. "Novel Cortical Target to Enhance Motor Output in Humans with Spinal Cord Injury." OUP Academic, Oxford University Press, 24 May 2017, academic.oup.com/brain/article/140/6/1619/3855040?searchresult=1.