Logopenic Progressive Aphasia

In this research study we want to learn more about the effects of non-invasive brain stimulation on memory and brain-network function in cognitively unimpaired older adults and in patients with amnestic mild cognitive impairment (aMCI). This study will use a form of non-invasive brain stimulation called repetitive Transcranial Magnetic Stimulation (rTMS). rTMS will slightly alter activity in an area of your brain that controls memory. Changes resulting from this stimulation will be measured with behavioral tests of memory and general cognition, as well as by taking images of your brain with Magnetic Resonance Imaging (MRI). Participants will come in for one baseline visit followed by 10 days of daily rTMS study visits (Monday through Friday) and an evaluation visit. Then, there will be a 2-week break. After this break, they will return for another baseline visit, an additional 10 days of rTMS, and a final evaluation visit.

While many have strongly suggested that transcranial direct current stimulation (tDCS) may represent a beneficial intervention for patients with primary progressive aphasia (PPA), this promising technology has not yet been applied widely in clinical settings. This treatment gap is underscored by the absence of any neurally-focused standard-of-care treatments to mitigate the devastating impact of aphasia on patients' family, work, and social lives. Given that tDCS is inexpensive, easy to use (it is potentially amenable to home use by patients and caregivers), minimally invasive, and safe there is great promise to advance this intervention toward clinical use. The principal reason that tDCS has not found wide clinical application yet is that its efficacy has not been tested in large, multi-center, clinical trials. In this study, scientists in the three sites that have conducted tDCS clinical trials in North America-Johns Hopkins University and the University of Pennsylvania in the US, and the University of Toronto in Canada, will collaborate to conduct a multi-site, Phase II clinical trial of tDCS a population in dire need of better treatments.

The goal of this clinical trial is to learn whether a personalized, multi-component, virtual speech language treatment program can improve communication and quality of life for adults with primary progressive aphasia (PPA) and their primary communication partners. The study will enroll participants who speak English and/or Spanish. The main questions the study aims to answer are: * Is the telerehabilitation program feasible and acceptable for people with PPA and their study partners? * Do participants with PPA and study partners find treatment beneficial? * What patterns of treatment response are seen in participants? * Which outcome measures are most useful for evaluating changes in communication and quality of life? Researchers will compare participants who receive intervention immediately to participants assigned to a waitlist control group (who will receive treatment after a delay) to see whether participation in the treatment program is associated with improvements in communication and quality of life. Participants will: * Take part in speech language therapy sessions delivered by video visit that combine restorative, compensatory, and partner-focused communication strategies. Treatment may take place after a waiting period. * Receive education and communication training together with their partner. * Complete speech, language, and cognitive assessments. * Complete questionnaires about communication abilities, daily functioning, and quality of life.

AD afflicts over 5.5. million Americans and is one of the most expensive diseases worldwide. In AD the variant in which language functions are most affected are referred to as 'logopenic variant Primary Progressive Aphasia' (lvPPA). Language deficits dramatically impair communication and quality of life for both patients and caregivers. PPA usually has an early onset (50-65 years of age), detrimentally affecting work and family life. Studies have identified verbal short-term memory/working memory (vSTM/WM) as a primary deficit and cause of language impairment. In the first cycle of this award, the investigators asked the question of whether language therapy effects could be augmented by electrical stimulation. The investigators conducted the largest to-date randomized, double-blind, sham-controlled, crossover, clinical trial to determine the effects of transcranial direct current stimulation (tDCS) in PPA. The investigators found that tDCS over the left inferior frontal gyrus (L\_IFG), one of the major language hubs in the brain, significantly enhanced the effects of a written naming and spelling intervention. In addition, findings demonstrated that tDCS modulates functional connectivity between the stimulated area and other networks (e.g. functionally and structurally connected areas), and that tDCS modulates the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). In terms of tDCS, the investigators have been identified several predictors to determine the beneficience of tDCS including (a) PPA variant, (b) initial performance on cognitive/language tasks, particularly vSTM/WM, and (c) initial white-matter integrity and structure. These findings support the notion that tDCS benefits generalize beyond the treatment tasks and has led to the important question of the present study: How can we implement treatments to product benefits that maximally generalize to untrained but vital language/cognitive functions. To address the above question, the investigators will test recent neuroplasticity theories that claim that the benefits of neuromodulation to language-specific areas generalize to other language functions within the language network, while neuromodulation of a domain-general/multiple-demands area generalizes to both domain-general, executive and language functions. The two areas to be stimulated will be the supramarginal gyrus (SMG) and left dorsolateral prefrontal cortex (DLPFC) respectively. The left supramarginal gyrus (L\_SMG) in particular, specializes in phonological processing, namely phonological verbal short-term memory (vSTM), i.e., the ability to temporarily store phonological (and graphemic) information in order. The domain of vSTM affects many language tasks (repetition, naming, syntax), which makes it an ideal treatment target and the L\_SMG an ideal stimulation target, since generalization of tDCS effects to other language tasks is driven by the function (computation) of the stimulated area. By testing a fundamental principle of neuromodulation in a devastating neurodegenerative disorder, the investigators will significantly advance the field of neurorehabilitation in early-onset dementias. Aim 1: To determine whether vSTM/WM behavioral therapy combined with high definition (HD)-tDCS over the L\_SMG will induce more generalization to language-specific tasks than to executive tasks, whereas stimulation over the LDPFC will induce equivalent generalization to both executive and language-specific tasks. Aim 2: To understand the mechanism of tDCS by measuring tDCS-induced changes in network functional connectivity (FC) and GABA in the LSMG and LDPFC. The investigators will carry out resting-state functional magnetic resonance imaging (rsfMRI), (MPRAGE), diffusion-weighted imaging (DWI), perfusion imaging (pCASL), and magnetic resonance spectroscopy (MRS), before, after, and 3-months post-intervention. Aim 3: To identify the neural, cognitive, physiological, clinical and demographic characteristics (biomarkers) that predict sham, tDCS, and tDCS vs. sham effects on vSTM and related language tasks in PPA. The investigators will evaluate neural (functional and structural connectivity, cortical volume, neuropeptides, and perfusion), cognitive (memory, attention, executive) and language functions, clinical (severity), physiological (sleep), and demographic (age, gender) characteristics, and the investigators will analyze the effects on vSTM and other language/cognitive outcomes immediately after intervention and at 3 months post-intervention.