Low-Frequency Quadruple Target Transcranial Magnetic Stimulation for Severe Levodopa-Induced Dyskinesia in Parkinson's Disease: A single case report

Abstract

Levodopa-induced dyskinesias (LID) are a common and debilitating complication in patients with advanced Parkinson’s disease (PD), significantly impairing quality of life. While single-target transcranial magnetic stimulation (TMS) has shown limited efficacy, multitarget approaches tailored to patient-specific symptomatology remain unexplored. Objective: This case report describes the development and application of a novel lowfrequency multitarget TMS protocol designed to address severe, refractory LID in a PD patient. Methods: A 77-year-old male with advanced PD (Modified Hoehn and Yahr Stage 4) and debilitating LID underwent a personalized TMS protocol. The treatment involved 20 sessions over two weeks, targeting six cortical regions through four stimulation sites, with sequential low-frequency stimulation. Symptomatology was assessed using the Dyskinesia Diary, the Abnormal Involuntary Movement Scale (AIMS), and subjective improvement scales. Results: Dyskinesias decreased significantly, from an average of 8–10 hours per day to 2 hours daily during treatment, and were further reduced to 0–1 hour daily following a levodopa dose adjustment. Improvements persisted for up to six weeks post-treatment. The AIMS score improved from 23 (baseline) to 2 (post-treatment). Non-motor symptoms, including mood and speech articulation, also showed marked improvement. The patient reported mild, transient post-treatment rigidity and bradykinesia, which resolved with levodopa adjustments. Conclusion: This case demonstrates the potential efficacy of a multitarget low-frequency TMS protocol in managing severe LID, highlighting its role as a noninvasive alternative for patients unsuitable for deep brain stimulation (DBS). However, the findings are limited by the single-patient design, the absence of a control group, and the relatively short follow-up period. These limitations underscore the need for larger studies with sham-controlled designs and extended follow-ups to validate this approach and explore its long-term outcomes.