Non-invasive Brain Stimulation to Enhance Treatment of Dysarthria Post-stroke

Modulation of Primary Motor Cortex to Enhance Treatment of Dysarthria Post-stroke

The proposed study aims to determine if transcranial direct current stimulation can enhance the effect of speech therapy in post-stroke patients with dysarthria.

A total of 60 Cantonese-speaking post-stroke patients who are suffering from dysarthria will be recruited and randomly divided into real tDCS and sham groups. All the participants will receive individualized speech therapy based on the results of their speech assessment.

For the real tDCS group, an anodal high-definition tDCS of 2 milliamperes (mA) lasting for 20 minutes will be delivered to the orofacial area of the primary motor cortex (SM1) during speech therapy. For the sham tDCS group, stimulation given during speech therapy will only last for 30 seconds in order to cause a similar sensation on the scalp as the real stimulation group. There will be a total of 10 daily sessions during a 2-week period.

Inclusion Criteria:

• Cantonese-speaking adults who had their first stroke and have suffered dysarthria post-stroke.
• Both acute and chronic stroke participants will be recruited.

Exclusion Criteria:

• Individuals with a personal or family history of epilepsy or seizures;
• Individuals with a history of another neurological condition (which is not a result from the initial stroke);
• Individuals with a history of speech disorders, voice disorders, oro-maxillo-facial surgery involving the tongue and/or lip, severe cognitive impairment, severe aphasia;
• In an unstable or serious medical condition;
• Have a cardiac implant metallic foreign body implant and/or any medications that lower neural thresholds (e.g. antidepressants, neuroleptic agents, etc.).