The Effect of Non-invasive Brain Stimulation on Language Production in Post-stroke Aphasia

The Effect of Speech and Language Therapy With and Without Transcranial Direct-current Stimulation on Discourse Production in People With Post-stroke Aphasia: a Pilot Randomised Controlled Trial

Aphasia is a language impairment caused by brain injury such as stroke that affects the ability to understand and express language, read and write due to damage in the language regions of the brain. Non-invasive brain stimulation (NIBS) techniques like transcranial direct-current stimulation (tDCS) have been found to improve aphasia treatment effects in post stroke patient populations such as improved naming abilities.

However, the effect of tDCS on more functional, higher level language skills such as discourse production (i.e. story telling, giving instructions) has yet to be understood.Therefore the aim of this study is to determine the potential effectiveness of tDCS as an adjunct to speech and language therapy (SLT) to improve discourse speech production in people with post-stroke aphasia. It is hypothesised that SLT combined with tDCS will result in greater improvements in discourse language production compared to SLT on its own.

Inclusion Criteria:

• aphasia caused by a single stroke
• at least 6 months post stroke
• at least 18 years old
• competent English speaker prior to stroke
• right handed prior to stroke
• normal aided or unaided visual acuity
• willing to participate and to comply with the proposed block of intervention and testing regime.

Exclusion Criteria:

Persons with

• neurological symptoms or history of a neurological event other than their stroke
• contraindications to tDCS including history of epilepsy or seizures and pacemakers
• global/severe aphasia
• cognitive impairment identified by a score less than 20/30 in the Montreal Cognitive Assessment
• left-handed dominance prior to stroke
• visual problems which interfere with persons' ability to access visual materials (i.e. pictures)
• inability to attend sessions