Thirty-one individuals (20 male) with chronic aphasia following a left-hemisphere (LH) stroke were recruited from the greater Boston and Chicago areas. Ten of these individuals served as natural history controls in that they were tested at baseline and, again after a three- to six-month period without treatment. Twenty-seven of these individuals, five of whom started out in the natural history control group (BU08/BUc01, BU19/BUc02, BU16/BUc05, BU24/BUc06), participated in up to 12 weeks of therapy and thus comprised the treatment group in this study. See Table 1 for demographic information for both treatment and natural history control participants (i.e., age, months post onset (MPO), cognitive-linguistic severity, aphasia type, apraxia of speech (AOS) status, baseline performance on the confrontation naming screener, treatment/generalization effect sizes (ES), and average accuracy on trained and untrained categories at pre- and post-treatment). All participants demonstrated adequate vision and hearing (i.e., passed screening at 40db HL bilaterally/or able to be corrected with increased volume); were English-proficient pre-morbidly (per self or family report); presented with stable neurological and medical status; and were not receiving concurrent individual speech and language therapy. None of the participants had neurodegenerative disease or active medical conditions that affected their ability to participate in the study. Written consent to participate in the study was obtained in accordance with the Boston University Institutional Review Board (IRB) protocols for 29 patients and per the Northwestern University IRB protocols for two participants.1 Of note, data from the 27 individuals in the treatment group were also included in a separate study examining the influence of baseline language and cognitive skills on treatment success (Gilmore, Meier, Johnson, & Kiran, 2018 , under revision).
The diagnosis of aphasia was determined through administration of the WAB-R. Participants were administered a180-item confrontation naming screener consisting of items from five semantic categories (i.e., birds, vegetables, fruit, clothing and furniture) including 36 exemplars of each category, and further divided into half-categories by typicality (i.e., 18 typical; 18 atypical). During the screener, pictures were presented in random order and participants were instructed to name the items. In addition to production of the intended target, responses were considered correct if they were self-corrections, altered due to dialectal differences, distortions or substitutions of one phoneme, and/or produced correctly following a written self-cue. Participants were included in the study if they demonstrated stable performance of ≤ 65% average accuracy in two different half-categories (e.g., Atypical Birds, Typical Clothing) across multiple baselines of the screener. Individuals with AOS were enrolled in the study as long as they were stimulable to produce targets with a verbal model from a clinician. The AOS rating in Table 1 was based on the Screen for Dysarthria and Apraxia of Speech (S-DAOS) (Dabul, 2000 ) and clinical judgment. In cases when AOS severity per the S-DAOS and primary clinician’s judgment did not align (e.g., patients with phonological errors judged as having AOS on S-DAOS), at least two trained speech-language pathologists (SLP) judged absence or presence of AOS based on pre-treatment speech samples.