Nearly one-third of adults will experience some symptoms of insomnia in their lifetime, whether it be lack of sleep, low sleep quality, or waking up at inappropriately early times [1]. Changes in just sleep quality may not seem like a particularly important issue on its own, but these issues can further cascade to more serious health issues such as obesity, immunodeficiencies, and other cognitive disorders [2]. Currently, insomnia is usually treated in two ways–cognitive behavioral therapy (CBT) or medication [3]. However, both methods have their own shortcomings: CBT requires a long treatment duration and has varying degrees of success based on individual patients while medication treatment comes with the risk of side effects that cause other health issues, such as memory disorders. Both methods can also ultimately become very pricey [3]. With how common insomnia is in many communities, repetitive transcranial magnetic stimulation, or rTMS, is emerging as an option for more consistent, affordable therapy for insomnia in the clinical setting. A group of researchers in China have recently investigated the use of repetitive transcranial magnetic stimulation (rTMS) to help alleviate symptoms of insomnia [4]. rTMS is a brain stimulation technique that involves placing a large magnetic coil on the scalp, which in turn sends magnetic pulses to the brain in order to depolarize the select regions on the surface of the brain. The depolarization of the underlying brain regions can regulate the excitability and activity of the neurons, affecting their neurotransmitter levels and synaptic connections that may be disrupted by neurological conditions [5]. rTMS isn’t particularly new technology, with well-researched clinical applications in other brain disorders such as depression and PTSD. However, its application in treating insomnia is still rather novel. The researchers reasoned that since rTMS has the ability to help control the activity of brain areas it stimulates, then this technology could also be used to strengthen neural connections termed small-world networks [4]. For their study, the researchers chose a group of healthy participants and a group of patients with primary insomnia to receive magnetic stimulation. Different from prior studies, the variables of the rTMS treatment were personalized to each patient’s individual needs- in this case, sleep. Prior to receiving the treatment, grouping algorithms were used to determine the optimal target area of the brain to administer the treatment. Patients received ten fifty-minute sessions of this treatment over five consecutive days and were subsequently evaluated upon completion of the study [4].

Figure 1: The repetitive transcranial magnetic stimulation (rTMS) treatment can impact brain connectivity. Through advanced statistical analysis, significant reductions in functional connections were observed in patients with Post-stroke Impairment (PI) during follow-up compared to their baseline measurements. The key brain regions affected by these changes include the anterior cingulate gyrus (ACG), medial superior frontal gyrus, superior and inferior parietal gyrus, middle temporal gyrus, thalamus, and insula. [5]

After the duration of the personalized rTMS treatment, researchers found that the strength of insomnia patient’s neural networks related to sleep was on par with that of their normal, healthy counterparts [4]. Participants also self-reported lower levels of depression and anxiety after the duration of the treatment. Researchers tracked the method’s effectiveness using magnetic resonance imaging, which ultimately showed decreased neurological communication between the center of the cerebral cortex and the frontal gyrus that caused overactive brain activity in individuals with insomnia. These regions are both integral to high-order brain functions such as attention and decision-making. When these brain regions are at a constant state of awareness, the networks in the brain are overused and overstimulated, making it difficult to arrive at a resting state for normal sleep [4].

While the underlying mechanisms of insomnia are still under investigation, this research helps reaffirm that abnormal connectivity between brain regions may be related to insomnia and provides a more concrete area of therapeutic attack in which rTMS could be used to alleviate symptoms. This research further supports existing findings that abnormal connectivity promotes insomnia and provides a more concrete area of attack in which rTMS could be used to alleviate insomnia.

References: 

[1] Bollu, P. C., & Kaur, H. (2019). Sleep Medicine: Insomnia and Sleep. Missouri medicine, 116(1), 68–75.

[2] Beccuti, G., & Pannain, S. (2011). Sleep and obesity. Current opinion in clinical nutrition and metabolic care, 14(4), 402–412. https://doi.org/10.1097/MCO.0b013e3283479109

[3]Irwin M. R. (2015). Why sleep is important for health: a psychoneuroimmunology perspective. Annual review of psychology, 66, 143–172. https://doi.org/10.1146/annurev-psych-010213-115205

[4] Qi, S., Zhang, Y., Li, X., Sun, C., Ma, X., Li, S., … Huang, Z.-G. (2022). Improved functional organization in patients with primary insomnia after individually-targeted transcranial magnetic stimulation. Frontiers in Neuroscience, 16. doi:10.3389/fnins.2022.859440 

[5] Mann SK, Malhi NK. (2023). Repetitive Transcranial Magnetic Stimulation.. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. 2023 Jan. https://www.ncbi.nlm.nih.gov/books/NBK568715/