HD-tDCS for Phonological Impairment in Aphasia

This study will investigate the effects of mild electrical stimulation in conjunction with speech therapy for people with post-stroke aphasia to enhance language recovery.

Aphasia is a disturbance of language, primarily caused by brain injury to the left cerebral hemisphere. Aphasia treatments include speech and language therapy and pharmacologic therapy, but several studies have found that these treatments are not completely effective for patients with aphasia, leaving them with residual deficits that significantly add to the cost of stroke-related care. Additionally, the amount and frequency of speech and language therapy delivered may have a critical effect on recovery. Therefore, there is a need for new treatments or adjuncts to existing treatments, such as brain stimulation interventions, that have the potential to show greater improvements in patients with aphasia. One such new approach for non-invasive brain stimulation is transcranial direct current stimulation (tDCS). This study will examine the effects of tDCS during speech therapy to further examine which method or methods is best for patient recovery. Patients enrolled in the study will undergo language testing that covers a broad range of language functions. Functional Magnetic Resonance Imaging (fMRI) will be completed before and after speech therapy intervention arms to investigate the neural processes affected by tDCS and speech therapy. Study design: Patients will be randomly assigned to one of 2 speech therapy groups as well as randomly assigned to one of 2 stimulation groups (active anodal stimulation or sham). Patients will receive one of two different speech therapy treatment interventions to focus on specific processing deficits. Participants will undergo neuropsychological evaluation and fMRI assessment before receiving targeted anodal-tDCS or sham-tDCS for 10 therapy sessions. Participants will then be re-tested using the behavioral assessment measure and fMRI before crossing over to receive the tDCS intervention again, along with the same speech therapy arm. They will complete a behavioral assessment and fMRI at 3 months post Treatment 2 and a final behavioral assessment at 6 months post Treatment 2.

Participants will maintain one of two speech therapy modalities throughout the study and be assigned to either targeted anodal-tDCS or sham-tDCS.

Participants will be randomized to receive either phonologic-focused speech therapy or semantic-focused speech therapy

High-Definition-tDCS will be delivered via a battery-driven constant direct current stimulator (Soterix) using a 4x1 montage (1 central anodal electrode and 4 cathodal electrodes) arranged in a HD-cap. Anodal or sham tDCS will be administered.

Percent improvement on behavioral outcomes after each therapy cycle will be the primary behavioral outcome measure.

Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post completion of therapy

Inclusion Criteria: Patients must be 18 or older. Patients may not be older than 85. Patients must have a language deficit from left-sided focal neurologic damage (e.g. stroke, tumor). Patients must be adults and have English-language fluency. Patients must be eligible to undergo MRI. Beyond meeting the inclusion criteria, no preference will be given on the basis of race, ethnicity or gender. Exclusion Criteria: Advanced neurodegenerative disease (i.e. Stage 3 Alzheimer's disease) Neurologic disease (e.g. idiopathic epilepsy, seizure disorders that are not well managed, Parkinson's disease, ALS), Severe psychopathology (e.g. schizophrenia, bipolar disorder, acute major depressive episode) Suspected or diagnosed uncorrectable hearing or vision difficulties, or developmental disabilities (i.e. intellectual disability or learning disability). Contraindications to MRI such as claustrophobia, implanted electronic devices, MRI-incompatible metal in the body, extreme obesity, pregnancy, inability to lie flat, inability to see or hear stimulus materials. Younger than 18 or older than 85. < 6 months post tumor resection.

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