Transcranial Magnetic Stimulation in Parkinson’s Disease and Parkinsonian Syndromes: A “State-of-Art” Perspective

Transcranial magnetic stimulation (TMS) is a widely used non-invasive brain stimulation techniques that gained growing interest as a diagnostic and therapeutic tool for Parkinson’s disease (PD), as well as for some atypical parkinsonisms and secondary parkinsonian syndromes. Briefly, TMS enables targeted stimulation of specific cortical regions through externally applied magnetic pulses, avoiding surgical intervention (as occurs in deep brain stimulation) and making it a safe, repeatable, and well-tolerated approach. Over the past two decades, extensive research has explored the clinical utility of TMS in PD, with particular emphasis on motor cortex excitability, synaptic plasticity, and functional connectivity, which are central contributors to both motor and non-motor symptoms in PD patients. In addition, TMS has been shown to modulate cortical plasticity, i.e., the brain’s capacity to reorganize neural circuits, suggesting potential benefits for longer-term non-pharmacological management and rehabilitation protocols. More recently, studies have also investigated the role of TMS in atypical and secondary parkinsonisms, indicating that it may help characterize distinct neurophysiological abnormalities and provide symptomatic improvement in selected patients. This updated literature review critically synthesizes current evidence on the application of different TMS protocols across the spectrum of parkinsonian disorders, highlighting clinical potential, methodological limitations, and future research directions.