Transcranial Magnetic Stimulation Efficacy Across Age Groups

Purpose: Transcranial magnetic stimulation is a non-invasive brain stimulation technique that targets treatment-resistant depression and other psychological disorders. TMS involves delivering repetitive magnetic pulses to stimulate electrical activity in the brain, sending a depolarizing current to neurons in the targeted region. For treatment-resistant depression, TMS targets the dorsolateral prefrontal cortex, though for other disorders, the region targeted varies. It is possible that TMS utilizes the neuroplasticity of the brain to cause long-term changes in brain activity. Previous studies have also explored age-related changes in GABA receptors, which could also impact the efficacy of TMS . I hypothesize that younger age groups (18-25 years) would respond better because their brains are still in development. Methods: The Neurostar Magnetic Therapy Machine was used to treat each patient involved in the study. It is FDA approved for the treatment of Major depressive disorder (MDD) and obsessive-compulsive disorder (OCD). Correspondingly, the machine administered varying treatments for each disorder through altering total pulses, seconds of stimulation, and the time span of the break between stimulation. Within each disorder, these variables were kept constant. Treatment for MDD involved a standard total of 3000 pulses with intervals of 4 seconds of stimulation and 11 seconds of rest. Contrastingly, OCD treatment included a standard 2000 total pulses with 2 seconds of stimulation and a 20 second rest break in between. The final metric used for data analysis was the Standard Motor Threshold (SMT), which is a measure of the strength of the patient’s medication and varied between each patient. The PHQ-9 survey was the metric used to measure whether a patient had undergone remission, with a score of 0-4 indicating success. An initial PHQ-9 was completed prior to treatment, and then completed weekly, followed by a final survey post-treatment, yielding roughly 7-9 surveys exhibiting the changes in their respective disorders. For this study, only patients who fully underwent remission were included in the data set. Records of each patient’s PHQ-9 surveys were obtained digitally through the “Trakstar” EMR program, which held every completed survey of each patient. Results: The data supports that patients within the 41-60 age group were the most responsive to TMS. Following that age group in terms of responsiveness was the 18-25 age group, then the 61+ age group, and finally the 26-40 age group was ranked last. It can be posited that the reason for the highest rates of responsiveness in this age group is due to their lower neural plasticity, resulting in the changes caused by TMS to last longer. Conclusion: The results reflected that the 41-60 age group responded best, though all age groups had similar rates of responsiveness close to the 50% mark. Further study is needed to confirm the reasons as to why the 41-60 age group responded higher than the rest. Exploring TMS efficacy on patients with secondary disorders to MDD or experimenting with the idea of placing TMS treatments ahead of rounds of psychiatric medications can support the notion that TMS is a safe and effective psychiatric treatment of the future.