Speech disturbance is common in patients with Parkinson disease. Pharmacotherapy improves motor symptoms but has inconsistent effects on speech disturbance in PD patients. Transcranial magnetic stimulation (TMS) is a safe and non-invasive tool used for brain stimulation. Repetitive transcranial magnetic stimulation (rTMS) has positive effects on motor function of PD. Yet, its effect on speech disturbance seems to be inconclusive. Previous rTMS studies mainly focused on the primary motor cortex for PD speech disturbance. Nevertheless, we think supplementary motor area (SMA) may be a better target. Speech disturbance in PD may be associated with basal ganglia-thalamocortical motor circuits and SMA involves in the cortex part. In addition, neuroimaging studies showed that SMA were under-activation in PD patients. Therefore, we conduct this 3-year study including two experiments. The aim of the study is to determine if rTMS over SMA can improve the speech function of PD patients and change the functional connectivity of speech pathway in the brain. This will be the first study to investigate the effect of rTMS over SMA on speech.

Experiment 1

Inclusion Criteria:

• right-handed healthy adult volunteers who understand and agree on the informed consent of the study

Exclusion Criteria:

• pregnancy or possibility of pregnancy
• history of seizure
• family history of epilepsy
• metals in any part of the body.

Experiment 2

Inclusion Criteria:

• PD patients with speech disturbance who understand and agree on the informed consent of the study. The speech item scored 2 or 3 in the unified Parkinson's disease rating scale (UPDRS) part III.

Exclusion Criteria:

• dementia
• the history of stroke, brain lesion, other central nervous system diseases
• the contraindication of TMS which described above
• any contraindication of MRI