The goal of this clinical trial is to learn whether home-based brain stimulation combined with virtual speech-language therapy can improve communication abilities in adults with logopenic variant primary progressive aphasia (lvPPA), a language disorder most often caused by Alzheimer's disease.

The main questions the study aims to answer are:

• Is combining remotely supervised transcranial direct current stimulation (tDCS) with virtual speech-language therapy feasible and acceptable for people with lvPPA?
• Does this combined treatment lead to improvements in communication compared to speech-language therapy with sham (placebo) stimulation?
• Do individual brain characteristics help predict who benefits most from this treatment?

Researchers will compare participants who receive active tDCS plus virtual speech-language therapy to participants who receive sham (placebo) tDCS plus virtual speech-language therapy to see if active brain stimulation enhances communication outcomes.

Participants will:

• Complete speech-language therapy sessions delivered by video visit.
• Receive either active or sham tDCS that is remotely supervised and completed at home.
• Complete language and cognitive testing before and after treatment.
• Undergo brain imaging and other assessments to help understand treatment response.

Inclusion Criteria:

• Meets diagnostic criteria for primary progressive aphasia (PPA)
• Meets diagnostic criteria for logopenic variant PPA
• Attains score of 15 or higher on the Mini-Mental State Examination
• Has adequate hearing and vision (with hearing or vision aids, if needed)
• Is able to travel to research site and undergo MRI brain scan
• Has access to high speed internet and basic experience using a computer and the internet
• Is a fluent speaker of English
• Has a study partner who can co-enroll in the study, attend pre-treatment training at the research site, and be present for teleconference meetings, as needed

Exclusion Criteria:

• Speech and language deficits better accounted for by another neurological disorder
• Does not meet diagnostic criteria for logopenic variant PPA
• Scores less than 15 on the Mini-Mental State Examination
• Does not have a study partner who can co-enroll in the study
• Has contraindications for tDCS or MRI scan (History of seizures, head injury, craniotomy, skull surgery or fracture; History of severe or frequent migraines; Metallic implant in head or any metal in head; Pacemaker or cardioverter-defibrillator or any other stimulator; Chronic skin problems; Pregnancy)
• Has a history of stroke, epilepsy, or significant brain injury

De-identified individual participant data, including behavioral and MRI/fMRI data from 80 individuals with lvPPA and limited data from study partners, will be shared via the ICPSR repository. Data will be available at publication or within 9 months of database lock, and accessible for at least 10 years. Publicly shared datasets will exclude identifiable information, audio/video files, and non-skull-stripped imaging. Additional data may be shared via IRB-approved data-sharing agreements.

De-identified clinical trial data (participant level and summary level data, raw and processed) will be made available at the time of publication of the primary results or within 9 months of database lock, whichever comes first. We will also include relevant datasets as supplementary material accompanying articles submitted to PubMed Central. Data will be publicly available for 10 years following the end of the award and by request thereafter.

De-identified data will be accessible to researchers and the broader scientific community. Publicly available datasets will be hosted on the ICPSR repository and accessible via DOI. Additional data (e.g., voice samples) may be accessed through an IRB-approved data-sharing agreement, which will require users to commit to secure data handling and non-identification of participants.