Quantifying insertional effects in deep brain stimulation: clinical outcomes and neurophysiological mechanisms

Deep brain stimulation (DBS) has revolutionized the treatment of various neurological and psychiatric disorders. However, recent findings highlight the significant clinical and molecular responses elicited by the mere insertion of DBS electrodes, termed ‘insertional effects.’ This review explores the clinical manifestations and underlying mechanisms of these effects, emphasizing their implications for neuromodulation therapies. A comprehensive literature search was conducted, examining studies that document the clinical benefits observed immediately following DBS electrode implantation in conditions such as Parkinson’s disease, epilepsy, chronic pain, and psychiatric disorders. The review delves into the molecular and cellular mechanisms, including neuroinflammatory responses and ion channel dynamics, that contribute to these insertional effects. Additionally, the potential for these effects to predict DBS efficacy and inform the development of closed-loop DBS systems is discussed. The insertional effects of DBS represent a crucial yet underappreciated phenomenon with significant implications for optimizing therapeutic protocols and enhancing patient outcomes. Recognizing and harnessing these effects could lead to more personalized and effective neuromodulation strategies, advancing the field of DBS and improving treatment for a range of neurological and psychiatric disorders. Deep brain stimulation (DBS) is used to treat neurological and psychiatric disorders. This review examines the immediate effects that occur when DBS electrodes are implanted, referred to as insertional effects, which can result in both beneficial and adverse outcomes. By understanding these effects, clinicians can better tailor DBS treatments and develop new technologies that improve patient outcomes.