Clinical outcomes at 6 months after MRgFUS thalamotomy in Parkinson’s disease: a large longitudinal cohort study

BACKGROUND: Magnetic resonance-guided focused ultrasound (MRgFUS) is an expanding therapy for tremor in Parkinson's disease (PD). This study aimed to characterize trajectories of tremor and cognitive functions following MRgFUS treatment over 24 hours, 1 month, and 6 months, and to explore potential predictors of outcomes. METHODS: This single-center, prospective, observational cohort study included PD patients undergoing MRgFUS over a 7-year period. Tremor severity was assessed using the Fahn-Tolosa-Marin Tremor Rating Scale (FTM) and the Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS-III). Cognitive performance was evaluated using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). RESULTS: 107 patients were included. Tremor severity showed a significant time effect (FTM and MDS-UPDRS-III: both p < 0.001), with a marked reduction at 24 hours followed by partial attenuation and stabilization over time, while remaining lower than baseline at 1 and 6 months (both p < 0.001). The 24-hour improvement was greater in patients with longer disease duration, who showed higher baseline severity (p < 0.001) and converged to cohort-level severity at post-treatment timepoints (all p ≥ 0.085). Cognitive status (MMSE and MoCA scores) remained stable throughout follow-up (all p ≥ 0.287). Levodopa equivalent daily dose (LEDD) significantly decreased from baseline to 6 months (F = 19.992, p < 0.001), suggesting a reduced need for dopaminergic treatment following tremor improvement. CONCLUSIONS: MRgFUS provided meaningful tremor improvement without negative effects on cognition. The significant LEDD reduction at 6 months supports a beneficial medication-sparing effect associated with tremor improvement.