rTMS for the Treatment of Freezing of Gait in Parkinson's Disease

Freezing of gait (FOG) is a common and debilitating symptom in patients with Parkinson's disease (PD), characterized by sudden and brief episodes of inability to produce effective forward stepping. FOG is a major risk factor for falls, and greatly contributes to reduced mobility and quality of daily life. Treatment of FOG has been perceived as a very challenging task. Although various treatment approaches exist, including pharmacological and surgical options, evidence is inconclusive for many approaches and no clear treatment protocols are available until now.

Repetitive transcranial magnetic stimulation (rTMS), a noninvasive neural modulation technique, has been closely applied as a treatment for various neurologic and psychiatric disorders. A recent meta-analysis demonstrated that rTMS could improve motor symptoms for PD patients with a moderate effect size. To date, however, only few rTMS studies have focused on its efficacy on FOG in patients with parkinsonism, and most of them targeted the primary motor cortex or dorsolateral prefrontal cortex . Even though some evidence indicates the involvement of the SMA in FOG, no report has described the SMA rTMS in PD patients with FOG.

Moreover, few studies combined functional magnetic resonance imaging (fMRI) and rTMS to unravel the mechanism of its beneficial effects. To address these issues, the investigators conducted a randomized, double-blind, sham-controlled study to explore the efficiency of SMA-rTMS on FOG in PD patients.

Inclusion criteria

• Idiopathic PD patients.
• Presenting with FOG.
• The mini-mental state examination questionnaire score above 24 points.

Exclusion criteria

• Other neurological or psychiatric disorders.
• History of epilepsy, seizures or convulsions.
• Metal implantation.
• History of exposure to rTMS in the past (to minimizing risk of unblinding sham condition).