Non-invasive Brain Stimulation as a Treatment for Dysarthria Post-stroke

A Randomized Controlled Trial Study of the Use of Transcranial Direct Current Stimulation (tDCS) in Treating Dysarthria Post-stroke

The proposed study aimed to determine if tDCS can help post-stroke patients with dysarthria.

A total of 9 Cantonese-speaking chronic post-stroke patients who are suffering from dysarthria was recruited and randomly divided into treatment group and sham group. For the treatment group, an anodal high-definition tDCS of 2 milliampere (mA) lasting for 15 minutes was delivered to the primary motor cortex (SM1) in 10 daily sessions during a 2-week period. For the sham tDCS group, the same setting of tDCS electrodes was applied on the scalp, but the stimulation only lasted for 30 sec in order to cause similar sensation on the scalp as the other group. Simultaneous to the tDCS stimulation, both groups will receive speech and voice therapy for 30 minutes.

An array of outcome measures reflecting speech production ability including acoustic, kinematic, perceptual and self-perceptual qualities was obtained before and after stimulation. It was anticipated that post-stroke dysarthric patients will see improvement in speech production after stimulation. The results provided important insights into the effects of tDCS on articulatory movement in individuals with dysarthria post-stroke.

Inclusion Criteria:

• Cantonese-speaking adults
• At least 6 months after their initial stroke
• Dysarthria post-stroke

Exclusion Criteria:

• A personal or family history of epilepsy or seizures
• A history of another neurological condition
• Speech disorders
• Voice disorders
• Oro-maxillo-facial surgery involving the tongue and/or lip
• Severe cognitive impairment
• Severe aphasia
• Heart disease
• Metallic foreign body implant
• On medications that lower neural thresholds (e.g. tricyclines, antidepressants, neuroleptic agents, etc.)