The purpose of this study is to evaluate the effectiveness of small amounts of electrical current, applied without surgery to the brain, in combination with speech-language treatment, on the language outcome of study subjects with nonfluent aphasia (i.e. difficulty with the comprehension and expression of spoken and written language) following a stroke.
Stroke is the third leading cause of death and the most common cause of disability in the United States. According to the American Stroke Association, the prevalence of stroke in the U.S. is approximately 4.8 million with approximately 700,000 additional strokes occurring annually. Approximately 150,000 to 250,000 stroke survivors becoming severely and permanently disabled each year.
A common neurological deficit among stroke survivors, and thus a substantial contributor to post-stroke disability, is aphasia. The loss of, or difficulty with language is extremely debilitating and has enormous social and economic impact on quality of life. Presently, the only treatment available for persons with aphasia is speech-language rehabilitation.
With rehabilitation only, however, many patients achieve a less than satisfactory improvement in speech-language function, and thus are left with significant disability.
Enhancing stroke recovery by facilitating brain plasticity with the direct application of stimulation to the cerebral cortex is a new area of investigation and shows promise for improving language recovery in stroke-induced aphasia, most probably when it is combined with intense learning. There are several methods of delivering cortical brain stimulation to modulate cortical excitability, each of which have been studied in animal models with promising results, and subsequently applied to the rehabilitation of motor deficits after stroke. Applications to language problems after stroke are only emerging. Nevertheless, results suggest a potential role for cortical stimulation as an adjuvant strategy in aphasia rehabilitation.
Of the cortical stimulation methods available, transcranial direct current stimulation (tDCS) has the greatest potential for clinical use in view of its non-invasive application, ease of administration and relatively low cost. tDCS is a method of delivering weak polarizing electrical currents to the cortex via two electrodes placed on the scalp. The nature of the effect depends on the polarity of the current. Anodal tDCS has an excitatory effect; cathodal tDCS induces inhibition.
This study proposes to evaluate the safety, feasibility, and effectiveness of anodal and cathodal tDCS in study subjects with Broca's aphasia after stroke, delivered concurrent with speech-language rehabilitation.
Subjects will receive speech and language therapy combined with either anodal, cathodal, or sham stimulation applied to the lesioned left hemisphere. The polarity conditions will be compared with each other and with sham stimulation, to determine safety, the degree to which improvements in language performance occur, and the degree to which they are maintained over time.
The protocol is single-blind. Neither the subjects nor the outcomes assessor will know what stimulation the subject received until the study's conclusion; the investigator applying the stimulation will know.
- Transcranial Direct Current Stimulation - Cathodal stimulation Device
Other Names: Cortical stimulation; Transcranial direct current stimulation Intervention Desc: Cathodal transcranial direct stimulation (tDCS) to the left hemisphere, 1.0 mA for 13 minutes, is received five days a week, for six weeks, during the initial 13 minutes of 90 minutes of speech-language treatment. ARM 1: Kind: Experimental Label: Cathodal stimulation
- Transcranial Direct Current Stimulation - Anodal stimulation Device
Other Names: Cortical stimulation; Transcranial direct current stimulation Intervention Desc: Anodal transcranial direct stimulation (tDCS) to the left hemisphere, 1.0 mA for 13 minutes, is received five days a week, for six weeks, during the initial 13 minutes of 90 minutes of speech-language treatment. ARM 1: Kind: Experimental Label: Anodal stimulation
- Transcranial Direct Current Stimulation - Sham stimulation Device
Other Names: No stimulation Intervention Desc: Sham stimulation provided together with 90 minutes of speech language therapy, 5 days a week, for 6 weeks. ARM 1: Kind: Experimental Label: Sham stimulation
- Allocation: Randomized
- Masking: Single Blind (Subject)
- Purpose: Treatment
- Endpoint: Safety/Efficacy Study
- Intervention: Parallel Assignment
|Type||Measure||Time Frame||Safety Issue|
|Primary||Aphasia Quotient (AQ) on the Western Aphasia Battery||Change from Baseline in Western Aphasia Battery at 6 weeks||No|
|Secondary||Functional communication skills||Change from Baseline in functional communication skills at 6 weeks||No|
|Secondary||Participation in everyday activities||Change from Baseline in participation in everyday activities at 6 weeks||No|
|Secondary||Western Aphasia Battery - Reading and Writing scores||Change from Baseline in Western Aphasia Battery Reading and Writing scores at 6 weeks||No|
|Secondary||Western Aphasia Battery Aphasia Quotient (Maintenance)||Change in Western Aphasia Battery AQ from 6 weeks to 12 weeks||No|
|Secondary||Western Aphasia Battery Reading and Writing Scores (Maintenance)||Change in WAB Reading and Writing Skills from 6 weeks to 12 weeks||No|
|Secondary||Functional Communication Skills (Maintenance)||Communication skills from 6 weeks to 12 weeks||No|
|Secondary||Participation in everyday activities (Maintenance)||Change in participation in everyday activities from 6 weeks to 12 weeks||No|