Brain Stimulation Effects on Post-Stroke Fatigue and Aphasia

• tDCS (active) (Device), also known as transcranial direct current stimulation: The investigators will administer active tDCS to left dorsolateral prefrontal cortex (DLPFC) during 10 sessions of behavioral treatment. For active tDCS, the current will slowly be increased to 2mA and applied for 20 minutes.
• Attention-focused sentence comprehension treatment (Behavioral): This is a specific type of speech-language therapy that focuses on simultaneously improving auditory comprehension and behavioral attention. Participants will receive 10 sessions of this treatment.
• Sentence comprehension treatment (Behavioral): This is a specific type of speech-language therapy that focuses on improving auditory comprehension . Participants will receive 10 sessions of this treatment.
• tDCS (sham) (Device), also known as transcranial direct current stimulation: The investigators will administer sham tDCS to left dorsolateral prefrontal cortex (DLPFC) during 10 sessions of behavioral treatment. For sham tDCS, the current will slowly be increased to 2mA over the course of 30 seconds and then immediately ramped back down to zero.

Primary outcomes

• Fatigue Interference and Severity Scale for Aphasia (FISS-A) [baseline; within 1 week following the final treatment session; 3- month follow-up]: Scale from 1-7, higher scores mean more significant fatigue

Secondary outcomes

• Continuous Performance Test (CPT) [baseline; within 1 week following the final treatment session; 3- month follow-up]
• Attention Network Test (ANT) [baseline; within 1 week following the final treatment session; 3- month follow-up]
• Sentence comprehension task [baseline; within 1 week following the final treatment session; 3- month follow-up]

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. 18 years or older.
2. No diagnosis of neurological disorder (other than stroke).
3. No diagnosis of psychiatric disorder, with the exception of anxiety and/or depression if it is managed through medication and/or behavioral intervention.
4. No seizure within the past 6 months.
5. Not pregnant.
6. Does not currently have cardiac pacemaker
7. In chronic phase of recovery, defined as at least 6 months post-stroke.
8. Not undergoing speech and language therapy targeting auditory comprehension or attention for the duration of the study.
9. No metal implants in the scalp or bone in the pre-frontal area of the head.
10. No unhealed skull fractures.
11. Onset of aphasia related to single, left hemisphere, ischemic stroke.
12. Damaged brain tissue from stroke does not overlap with left hemisphere dorsolateral prefrontal cortex.
13. Mild to moderate aphasia (as measured by WAB-R **or QAB).
14. Self-report of post-stroke fatigue (as measured on SF-CAT)
15. No significant challenges with vision or hearing (with use of corrective aids if needed; eyeglasses, hearing aids).
16. Willing to allow audio-recording of study sessions.

Exclusion Criteria:

1. Younger than 18 years old.
2. Diagnosis or history of neurological disorder other than stroke.
3. Diagnosis or history of psychiatric disorder with the exception of anxiety and/or depression if it is managed through medication and/or behavioral intervention.
4. History of seizures within the past 6 months.
5. Pregnant.
6. Currently has cardiac pacemaker
7. <6 months post-stroke (however, if this is only exclusionary criterion met, participant can be re-evaluated at the 6-month mark if still interested in the study)
8. Currently undergoing speech and language therapy targeting auditory comprehension or attention.
9. Metal implants in the scalp or bone in the pre-frontal area of the head.
10. Currently has an unhealed skull fracture.
11. Onset of aphasia related to etiology other than ischemic left hemisphere stroke.
12. Damaged brain tissue significantly overlaps with left hemisphere dorsolateral prefrontal cortex.
13. No aphasia or severe aphasia (as measured by WAB-R **or QAB).
14. Does not report experience of post-stroke fatigue (as measured on SF-CAT)
15. Significant challenges with vision and/or hearing (even with use of corrective aids).
16. Unwilling to allow audio-recording of study sessions.

NIH grants: R01DC021677