recruitment efforts did not result in a sufficient number of patients

The investigators assess if repetitive, transcranial alternating current stimulation (rtACS) can improve the speaking quality of the aphasic patient as well as other communication skills as naming, repeating and understanding spoken words, reading and writing. Further, it will be assessed if memory and attentiveness deficiencies after 10 days of therapy with brain stimulation are stabilized and remain stable after a training-free period of 60 days.

Inclusion Criteria:

• stroke
• lesion age at least 6 months
• aphasia with at least moderate severity according to Aachener Aphasia Test (AAT)
• age between 40 and 75
• German-speaking (at a native speaking level)

Exclusion Criteria:

• cognitive or speech-language therapy during the 2-weeks stimulation course
• intensive language training when exceeding 1 hour, 2 times a week during the 2-weeks stimulation course and the follow-up period (60 days after stimulation was completed)
• additional neurological diseases, e.g. surgical brain tumor removal, untreated tumor disease, acute traumatic brain injury, and/or craniotomy
• (severe) dysarthria
• untreated hypertension exceeding 160/100 mmHg (patients with treated hypertension and blood pressure below 160/100 mmHg can be included)
• increased risk of vascular thrombosis
• epilepsy, photo sensitivity, acute focal findings (patients without focal findings or epileptiform discharges can be included when they had only a single seizure more than 10 years ago)
• dementias and neurodegenerative diseases
• significant psychiatric disturbances, e.g. schizophrenia
• major attention and/or memory deficits
• major hearing loss
• patients with uncorrected visual deficits
• severe global aphasia
• modality-specific disorders (pure speech apraxia, pure alexia, pure agraphia)
• electric or electronic implants (e.g. heart pacemakers)
• metal artefacts located at the head
• medication with impact on the central nervous system (e.g. antidepressant or sedative drugs)
• participation in another trial
• pregnant or breastfeeding women