studying language with brain stimulation in aphasia

Conditions: Stroke; Aphasia

Summary: the overall goal of this study is to evaluate whether stimulation of two brain areas alongside behavioral speech-language therapy increases connectivity to improve language functions in stroke-aphasia patients.

the brain is made up of networks that communicate with each other to help us think and communicate. after a stroke, networks between different areas of the brain can lose connection. in the case of aphasia, networks in the language areas of the brain are often disrupted. there is currently no "fix" to restore these specific language connections. however, transcranial magnetic stimulation (tms) might help the areas reconnect through alternative pathways. tms is a non-invasive procedure (in other words, it takes place outside your body). a coil will be placed over your head. the coil sends magnetic pulses to your brain to stimulate, or excite, neurons. most studies using tms stimulate one area of the brain at a time, but this does not tell us how to improve the network connections between brain areas. for this study, we plan to stimulate two language areas of the brain to improve these network connections. to do this, we will use a form of tms called "cortico-cortical paired associative stimulation" (ccpas). this type of tms involves applying paired pulses to two different brain areas that have been "disconnected" from each other after a stroke. the pulses are delivered with a time difference, on other words, one pulse after another. if you choose to participate, you will be randomly assigned to one of two groups. there is a 50% chance you will receive active brain stimulation with speech-language therapy and a 50% chance that you will receive inactive or sham stimulation (no brain stimulation) along with speech-language therapy. neither you nor the clinician on the research project will choose - or know - which group you are assigned to. only the person administering the stimulation will know.

Eligibility criteria:
inclusion criteria: 1. diagnosis of non-fluent aphasia due to a single, left-hemisphere stroke 2. ≧ six months post-stroke onset 3. wab-r fluency, grammatical competence, and paraphasias score between 2-6 4. 18+ years of age 5. premorbidly right-handed 6. english-speaking 7. ability to participate in fmri / tms protocol exclusion criteria: 1. cardiac pacemaker or pacemaker wires; neurostimulators; implanted pumps 2. metal in the body (rods, plates, screws, shrapnel, dentures, iud) or metallic particles in the eye 3. surgical clips in the head or previous neurosurgery 4. any magnetic particles in the body 5. cochlear implants 6. prosthetic heart valves 7. epilepsy or any other type of seizure history 8. history of significant head trauma (i.e., extended loss of consciousness, neurological sequelae) 9. significant other disease (heart disease, malignant tumors, mental disorders) 10. significant claustrophobia 11. ménière's disease 12. medications that increase risk of seizures, for instance antipsychotic and antidepressant medications acting primarily on the central nervous system, which lower the seizure threshold such as antipsychotic drugs (chlorpromazine, clozapine) or tricyclic antidepressants 13. non-prescribed drug use, for instance recreational marijuana 14. unable to refrain from using any alcohol and nicotine products for at least 24 hours before the study visits.

Keywords: transcranial magnetic stimulation stroke aphasia language functional magnetic resonance imaging