In contrast to the traditional definition of the disorder, many individuals with aphasia exhibit non-linguistic cognitive impairments, including executive control deficits. Classic lesion studies cite frontal lobe damage in executive dysfunction, but more recent lesion symptom-mapping studies in chronic aphasia present mixed results. In this study, we compared executive control abilities of acute stroke survivors with and without aphasia and investigated lesion correlates of linguistic and non-linguistic cognitive tasks. Twenty-nine participants with acute left hemisphere stroke resulting in aphasia (n = 14) or no aphasia (n = 15) completed clinical MRI and testing, including three NIH Toolbox Cognition Batteries (Pattern Comparison Processing Speed, Flanker Inhibitory Control and Attention, and Dimensional Change Card Sort Tests) and the Boston Naming Test. We compared performance between groups using Wilcoxon rank sum tests. We used Least Absolute Shrinkage and Selection Operator Regression to identify neural markers (percent regional damage, hypoperfusion within vascular territories, and total lesion volume) of executive control deficits and anomia. Group performance was comparable on the Pattern Comparison Processing Speed Test, but people with aphasia had poorer standard scores, lower accuracy, and slower response times on the Dimensional Change Card Sort Test than people without aphasia. Damage to extrasylvian regions (dorsolateral prefrontal cortex, intraparietal sulcus) was related to executive control deficits, whereas language network damage (to inferior frontal and superior and posterior middle temporal gyri) was linked to naming impairments. These results suggest people with aphasia can exhibit comorbid executive control impairments linked to damage outside classic language network areas. Supplementary Information The online version contains supplementary material available at 10.1007/s11682-021-00580-y.

Background: Transcranial direct-current stimulation (tDCS) is a promising adjunct to therapy for chronic aphasia. Methods: This single-center, randomized, double-blind, sham-controlled efficacy trial tested the hypothesis that anodal tDCS augments language therapy in subacute aphasia. Secondarily, we compared the effect of tDCS on discourse measures and quality of life and compared the effects on naming to previous findings in chronic stroke. Right-handed English speakers with aphasia <3 months after left hemisphere ischemic stroke were included, unless they had prior neurological or psychiatric disease or injury or were taking certain medications (34 excluded; final sample, 58). Participants were randomized 1:1, controlling for age, aphasia type, and severity, to receive 20 minutes of tDCS (1 mA) or sham-tDCS in addition to fifteen 45-minute sessions of naming treatment (plus standard care). The primary outcome variable was change in naming accuracy of untrained pictures pretreatment to 1-week posttreatment. Results: Baseline characteristics were similar between the tDCS (N=30) and sham (N=28) groups: patients were 65 years old, 53% male, and 2 months from stroke onset on average. In intent-to-treat analysis, the adjusted mean change from baseline to 1-week posttreatment in picture naming was 22.3 (95% CI, 13.5–31.2) for tDCS and 18.5 (9.6–27.4) for sham and was not significantly different. Content and efficiency of picture description improved more with tDCS than sham. Groups did not differ in quality of life improvement. No patients were withdrawn due to adverse events. Conclusions: tDCS did not improve recovery of picture naming but did improve recovery of discourse. Discourse skills are critical to participation. Future research should examine tDCS in a larger sample with richer functional outcomes. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02674490.

No abstract

Most people with aphasia (PWA) improve in content of discourse over the first 6 months of stroke, but the extent to which increased content is compensatory, by learning to use more frequent or less complex words, is unknown. We hypothesized that PWA who improve in content units (CU; concepts produced by healthy speakers in describing the picture) in picture description show an increase in word frequency and decrease in articulatory complexity from acute stroke to 3 and 6 months. Methods: PWA <5 days of left hemisphere ischemic stroke (n=35) and age-matched controls (n=48) described the NIHSS picture. Patients were retested at 3 and 6 months post-stroke. We evaluated CU, articulatory complexity (https://unccard.shinyapps.io/shiny-woRdcomplex-2/) and word frequency (log10 frequency among 51 million words+1) each time. We used 2-tailed t-tests to compare groups and paired t-tests to evaluate changes from 0 to 3 and from 0 to 6 months after stroke. Results: Compared to controls, PWA produced fewer CU (mean 19.4 vs 47.6; t (df81) = 7.9; p<0.00001), with lower articulatory complexity (mean 3.0 vs 3.5; t (df81) = 2.8; p=0.006) and lower frequency (3.0 vs 3.3; t(df81) = 2.1; p=0.04) acutely. The 20 participants who improved in CU at 3 months showed an increase in word frequency at 3 months (mean 2.7 to 3.4; t (df19)= -2.0, p= 0.03), while those who failed to improve in CU showed no change. The 19 patients who improved at 6 months also tended increase in word frequency (from 3.0 to 3.5; t (df18)= -1.6; p= 0.07), while those who failed to improve showed a decrease (from 3.4 to 2.7; ns). Those who improved in CU showed an increase in articulatory complexity (mean 2.7 to 3.5, t(df18)= -2.3; p=0.03) at 3 months and 6 months (mean 3.3). Those who failed to improve in CU showed the opposite trend toward decrease in complexity (mean 3.3 acutely, 3.1 at 3 months, and 2.4 at 6 months; ns). Conclusions: Improved content in discourse by aphasic individuals over the first 6 months after stroke may in part reflect compensation by selecting more frequent words or increased function words (e.g. prepositions - which are high frequency) to describe a picture. Those who improve in content show an increase in articulatory complexity of words, indicating that increased complexity reflects improvement.