Experimental design
atrophy, aphasia, language deficit, nonfluent
DISEASE, ATROPHY
The data analyzed in this study were part of a larger randomized, double‐blinded, sham‐controlled, crossover study on aphasia treatment using tDCS. All of the analyzed subjects had at least 2 years of progressive language deficit and no history of any other neurological condition that may have affected their language ability. Subjects had atrophy predominantly in the left hemisphere. Subjects were diagnosed via neuropsychological testing, language testing, MRI, and clinical assessment according to consensus criteria (Gorno‐Tempini et al., Each subject was diagnosed with one of the PPA variant types: logopenic, nonfluent, or semantic. Randomization was conducted within each variant type with an equal probability assigned to either the tDCS or sham group. As shown in Table Patient demographics
A total of 50 right‐handed, native English‐speaking patients had a pre‐intervention scan (scan1) and 48 had a post‐intervention scan (scan2). One patient was deleted from the analysis because of missing values in the connectivity matrix. Among the remaining 47 post‐intervention scanned patients, 25 had transcranial direct‐current stimulation + language therapy and the remaining 22 patients had the sham treatment plus language therapy. Several baseline covariates were recorded including gender, disease onset (years), age at the start of therapy, and language severity. These patients were diagnosed with three variant types, including: logopenic, nonfluent, and semantic. Diagnoses were based on which function(s) were compromised. Patients with the 