Effect of rTMS at SMA on task-based connectivity in PD.

Area of Science:

• Neuroscience
• Neurology
• Rehabilitation Medicine

Background:

• Transcranial magnetic stimulation (TMS) offers potential for alleviating Parkinson's disease (PD) symptoms.
• Neuroimaging is crucial for understanding the neural mechanisms underlying rTMS interventions in PD.

Purpose of the Study:

• To investigate changes in cortical connectivity and motor performance following rTMS of the supplementary motor area (SMA) in PD patients.
• To utilize clinical assessments and task-based functional MRI (fMRI) to evaluate rTMS effects.

Main Methods:

• 16 PD subjects received weekly rTMS at the left SMA for 8 weeks (4 sham, 4 real sessions).
• Clinical outcomes (UPDRS, PDQ39) and task-based fMRI were assessed at baseline, week 4, and week 8.
• Visuo-spatial task fMRI and T1-weighted MRI were analyzed using multivariate pattern analysis (MVPA).

Main Results:

• Significant improvements (p < 0.05) were noted in UPDRS scores (II, III) and PDQ39 (Mobility, ADL) after real rTMS sessions.
• MVPA revealed significant activation clusters in the right precentral gyrus, superior/middle frontal gyri, thalamus, and cerebellum (p_FDR=0.001).

Conclusions:

• Weekly rTMS of the SMA yields clinical motor benefits in PD patients, improving dexterity and scale performance.
• Observed benefits are potentially mediated by altered connectivity in remote motor network regions.