tDCS and Aphasia Treatment

This project will investigate the use of noninvasive brain stimulation in the form of tDCS (transcranial direct current stimulation) in conjunction with speech-language therapy, for the improvement of language production in stroke survivors with aphasia. The hypothesis is that anodal tDCS and speech-language therapy will facilitate improved outcomes compared to speech therapy alone.

Aphasia, commonly defined as impairment or loss of language functions, is a frequent and often chronic consequence of stroke, with detrimental effects on patient autonomy and health-related quality of life (HRQOL). Although beneficial in some cases, the effectiveness of behavioral therapy is often limited, and therefore new complementary treatments must be developed in order to improve rehabilitation of post-stroke aphasia. In most individuals, language areas in the brain are localized in the left hemisphere. After stroke, there is evidence that the brain reorganizes such that either areas close to damaged language areas in the Left Hemisphere, or anatomically similar areas in the Right Hemisphere, are recruited to perform language tasks. Recently, studies have begun to examine the effects of non-invasive brain stimulation on aphasia rehabilitation. One such technique is transcranial direct current stimulation (tDCS), which involves administering weak electrical currents through surface electrodes on the scalp. The effects can either stimulate an area, or inhibit an area of the brain. The main hypothesis is that stimulating language areas in the Left Hemisphere in conjunction with speech language therapy will facilitate reorganization of language-relevant areas of the brain, and improve expression. The proposed study will compare the effects of transcranial direct current stimulation (tDCS) activating language centers in the Left Hemisphere and sham tDCS, in right-handed individuals with chronic post-stroke aphasia. This study will provide information on the effects of tDCS, in conjunction with speech-language therapy, on aphasia rehabilitation.

Anodal and sham tDCS will be administered. All of the participants will also receive behavioral speech-language therapy.

Naming will be tested using standardized tests such at the Boston Naming Test and or the Philadelphia Naming Test. In addition, sentence probes have been created that will assess naming in the sentence context throughout the study.

Inclusion Criteria: single left hemisphere stroke, more than three months post stroke, right handed, no other medical problems, ages 18-100 - Exclusion Criteria: more than one stroke, less than three months post stroke, other medical problems, pacemaker or other electronic implant (e.g. hip replacement), pregnancy -

Baker JM, Rorden C, Fridriksson J. Using transcranial direct-current stimulation to treat stroke patients with aphasia. Stroke. 2010 Jun;41(6):1229-36. doi: 10.1161/STROKEAHA.109.576785. Epub 2010 Apr 15.

Fiori V, Cipollari S, Di Paola M, Razzano C, Caltagirone C, Marangolo P. tDCS stimulation segregates words in the brain: evidence from aphasia. Front Hum Neurosci. 2013 Jun 14;7:269. doi: 10.3389/fnhum.2013.00269. eCollection 2013.

Elsner B, Kugler J, Pohl M, Mehrholz J. Transcranial direct current stimulation (tDCS) for improving aphasia in patients after stroke. Cochrane Database Syst Rev. 2013 Jun 25;(6):CD009760. doi: 10.1002/14651858.CD009760.pub2.