Vagus nerve stimulation (VNS) is one of the current and popular applications in the regulation of the autonomic nervous system (ANS). As the ANS is studied and researched in detail, it is observed that dysautonomia is influenced by many diseases. These diseases include Parkinson’s disease, cerebrovascular diseases, multiple sclerosis, diabetes, neuropathies, and many more. The ANS has various effects on the functions of many organs in the body. Its anatomical distribution is complex, involving many areas of both the central and peripheral nervous systems. Vagal neuromodulation can regulate the ANS and maintain homeostasis. The vagus nerve (VN) is the main component of the parasympathetic nervous system. It has been shown that VNS affects heart rate, blood pressure, and autonomic functions. Stress, mood disorders, and inflammatory diseases, which are caused by sympathetic hyperactivity, may therefore benefit from VNS. Thus, this book initially examines the effects of VNS in healthy individuals. Furthermore, it has been determined that VNS increases beta and gamma band powers in brain waves, which is consistent with increased parasympathetic activity.

Additionally, due to the effects of VN on the microbiota-gut-brain axis, studies have shown that it may have significant effects on controlling inflammatory bowel disease, which has limited treatment options. Not only the gut microbiome but also the oral microbiome is influenced by VN activity. VNS may also be beneficial in controlling diseases by affecting the microbiome in autism and neurodegenerative diseases. It is believed that personality traits and attachment patterns affect the response to VNS. Moreover, the effects of diet on VN have been examined, and it has been found that an Omega-3-rich Mediterranean diet increases parasympathetic activity. In obesity, the response to VN is reduced, suggesting that VNS may be a treatment alternative in obesity. VNS is also an FDA-approved treatment for refractory depression and epilepsy. Given that antidepressants and antiepileptics can pose risks during pregnancy, VNS, with a lower side effect profile, may be safer. Invasive VNS is frequently used in cases of refractory epilepsy. It is important for school nurses to be aware that symptoms such as voice changes and cough may appear in the early periods after device implantation. Further research is needed to elucidate the communication between the ANS and immune cells in inflammatory and autoimmune diseases like rheumatoid arthritis.

This book aims to pave the way for the wider use of VNS applications, emphasize its importance, and expand its application areas. With this purpose, the book is designed as a bedside resource for VNS practitioners, featuring an original structure and a wealth of current literature.

As the editor of this book, I extend my heartfelt thanks to all the authors of the chapters for their meticulous attention to detail and efforts in preparing the topics. Their dedicated work has greatly contributed to the educational richness of this book. The sharing of their experiences and current literature knowledge has been a crucial factor in enhancing the quality of our book. With this opportunity, I hope this book, which we aspire to be an inspiration to all our readers, opens new horizons in the world of VNS knowledge. I wish our book to be productive and enlightening for everyone.

Prof. Dr. Hasan Kerem ALPTEKİN
Editor
Bahçeşehir University Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, İstanbul, Türkiye