Defining aphasia: Content analysis of six aphasia diagnostic batteries.

Clear operational definitions of constructs are necessary to ensure that research findings are meaningful and interpretable. In the field of aphasiology, aphasia is often defined to the effect of "aphasia is an acquired language disorder often due to brain injury that affects expressive and receptive language." To contribute to our understanding of the construct of aphasia, we conducted a content analysis of six diagnostic aphasia tests: the Minnesota Test for the Differential Diagnosis of Aphasia, the Porch Index of Communicative Ability, the Boston Diagnostic Aphasia Examination, the Western Aphasia Battery, the Comprehensive Aphasia Test, and the Quick Aphasia Battery. These chosen tests have historical prominence, with several in regular clinical and research use today. We hypothesized that the content of the aphasia tests should be very similar since they all purport to identify and characterize (if present) aphasia, with recognition that there may be some subtle differences in test content stemming in large part to epistemological differences in the test makers' views of aphasia. Instead, we found predominantly weak Jaccard indices, a similarity correlation coefficient, between test targets. Only five test targets were found in all six aphasia tests: auditory comprehension of words and sentences, repetition of words, confrontation naming of nouns, and reading comprehension of words. The qualitative and quantitative results suggest that the content across aphasia tests may be more disparate than expected. We conclude by discussing the implication of our results for the field, including the importance of updating, if necessary, the operational definition of aphasia through conversation with a broad audience of interested and affected people.

Fatigue Influences Social Participation in Aphasia: A Cross-sectional and Retrospective Study Using Patient-Reported Measures.

OBJECTIVE: To examine associations between social participation, fatigue, and aphasia severity using patient-reported outcome measures and to examine associations between demographic/diagnostic variables and fatigue in people with aphasia. DESIGN: Retrospective analysis of patient-reported outcome measures using a Bayesian framework. SETTING: Urban rehabilitation research hospital. PARTICIPANTS: 67 participants (N=67) with chronic aphasia (mean age=54.1 years) as a consequence of stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Ability to Participate in Social Roles and Activities, Fatigue, and Global Health Questionnaire scales from the Patient-Reported Outcomes Measurement Information System initiative and the Western Aphasia Battery-Revised. We hypothesized an association between social participation and fatigue in people with aphasia. RESULTS: People with aphasia with higher fatigue levels tended to report less social participation. Also, people with aphasia who were a longer time post-stroke tended to report higher social participation. People with aphasia who reported better physical health were more likely to report higher social participation. CONCLUSIONS: There is an association between fatigue and social participation in people with aphasia. Fatigue should be considered in clinical assessments and treatments for this population.

Test-retest reliability of heart-rate variability metrics in individuals with aphasia.

Individuals with aphasia may have impairments in cognition, higher incidences of depression, and a variety of post-stroke functional impairments. However, evaluating these issues is challenging since most assessments require some degree of linguistic processing and task instructions are often verbal. Heart rate variability has shown to be an objective marker for cognitive functioning in neurologically healthy individuals, depression and post-stroke depression, and post-stroke functional impairments. However, before the utility of heart rate variability is established in persons with aphasia, its test-retest reliability needs to be established. The purpose of this study was to assess test-retest reliability of heart rate variability metrics in persons with aphasia. Heart rate variability was recorded at rest while in a sitting position in twenty-one persons with aphasia at two time points. Heart rate variability metrics were mostly moderately reliable. The majority of participants had resting heart rate variability parasympathetic and sympathetic indexes similar to those of neurologically healthy individuals. Further research is needed to establish the test-retest reliability of heart rate variability metrics in different postures and breathing conditions in persons with aphasia.

Longitudinal Trajectories of Post-Stroke Depression Symptom Subgroups.

BACKGROUND: Post-stroke depressive symptoms are prevalent and impairing, and elucidating their course and risk factors is critical for reducing their public health burden. Previous studies have examined the course of post-stroke depression, but distinct depressive symptom dimensions (eg, somatic symptoms, negative affect [eg, sadness], anhedonia [eg, loss of interest]) may vary differently over time. OBJECTIVE: The present study examined within-person and between-person associations between depressive symptom dimensions across 3 timepoints in the year following discharge from in-patient rehabilitation hospitals, as well as the impact of multiple clinical variables (eg, aphasia). METHODS: Stroke survivors completed the Center for Epidemiologic Depression Scale (CES-D) at discharge from post-stroke rehabilitation ("T1") and at 3-month ("T2") and 12-month ("T3") follow-ups. Scores on previously identified CES-D subscales (somatic symptoms, anhedonia, and negative affect) were calculated at each timepoint. Random intercept cross-lagged panel model analysis examined associations between symptom dimensions while disaggregating within-person and between-person effects. RESULTS: There were reciprocal, within-person associations between somatic symptoms and anhedonia from T1 to T2 and from T2 to T3. Neither dimension was predictive of, or predicted by negative affect. CONCLUSIONS: The reciprocal associations between somatic symptoms and anhedonia may reflect a "vicious cycle," and suggest these 2 symptom dimensions may be useful indicators of risk and/or intervention targets. Regularly assessing depression symptoms starting during inpatient rehabilitation may help identify stroke survivors at risk for depression symptoms and facilitate early intervention.

Complexity of Participation Post-Stroke: Longitudinal Assessment of Community Participation, Positive Affect, Social Support and Functional Independence.

OBJECTIVE: To investigate longitudinal, predictive associations between community participation, positive affect, social support, and functional independence for individuals post-stroke at 3 and 12 months post-discharge. DESIGN: Longitudinal design. SUBJECTS: Data from 544 participants were obtained from the Stroke Recovery in Underserved Populations (2005-06) database. METHODS: A cross-lagged panel network analysis to identify the complex set of predictive relationships between community participation, positive affect, social support, and functional independence 3 months post-discharge to 12 months post-discharge. RESULTS: Community participation, particularly religious/spiritual activities, was an early predictor of later motor (functional) independence and social support. In addition, positive affect was an early predictor of social support. CONCLUSION: While participation in social situations is a desired outcome post-stroke, the results of this study indicate the importance of identifying early factors that influence community participation throughout the recovery process.

Timing of transcranial direct current stimulation (tDCS) combined with speech and language therapy (SLT) for aphasia: study protocol for a randomized controlled trial.

BACKGROUND: Studies suggest that language recovery in aphasia may be improved by pairing speech-language therapy with transcranial direct current stimulation. However, results from many studies have been inconclusive regarding the impact transcranial direct current stimulation may have on language recovery in individuals with aphasia. An important factor that may impact the efficacy of transcranial direct current stimulation is its timing relative to speech-language therapy. Namely, online transcranial direct current stimulation (paired with speech-language therapy) and offline transcranial direct current stimulation (prior to or following speech-language therapy) may have differential effects on language recovery in post-stroke aphasia. Transcranial direct current stimulation provided immediately before speech-language therapy may prime the language system whereas stimulation provided immediately after speech-language therapy may aid in memory consolidation. The main aim of this study is to investigate the differential effects of offline and online transcranial direct stimulation on language recovery (i.e., conversation) in post-stroke aphasia. METHODS/DESIGN: The study is a randomized, parallel-assignment, double-blind treatment study. Participants will be randomized to one of four treatment conditions and will participate in 15 treatment sessions. All groups receive speech-language therapy in the form of computer-based script practice. Three groups will receive transcranial direct current stimulation: prior to speech-language therapy, concurrent with speech-language therapy, or following speech-language therapy. One group will receive sham stimulation (speech-language therapy only). We aim to include 12 participants per group (48 total). We will use fMRI-guided neuronavigation to determine placement of transcranial direct stimulation electrodes on participants' left angular gyrus. Participants will be assessed blindly at baseline, immediately post-treatment, and at 4 weeks and 8 weeks following treatment. The primary outcome measure is change in the rate and accuracy of the trained conversation script from baseline to post-treatment. DISCUSSION: Results from this study will aid in determining the optimum timing to combine transcranial direct current stimulation with speech-language therapy to facilitate better language outcomes for individuals with aphasia. In addition, effect sizes derived from this study may also inform larger clinical trials investigating the impact of transcranial direct current stimulation on functional communication in individuals with aphasia. TRIAL REGISTRATION: ClinicalTrials.gov NCT03773406. December 12, 2018.

Prospectively Predicting Adult Depressive Symptoms from Adolescent Peer Dysfunction: a Sibling Comparison Study.

Previous studies have shown that peer dysfunction in adolescence predicts depression in adulthood, even when controlling for certain individual- and/or family-level characteristics. However, these studies have not controlled for numerous potential familial confounders, precluding causal inferences. The present study therefore used a sibling comparison design (i.e., comparing siblings within families) to test whether peer dysfunction (e.g., lack of friendships, victimization) in adolescence continues to predict depression in adulthood after accounting for unmeasured familial confounds and individual characteristics in adolescence. Participants' (N = 85) dysfunction with peers was assessed in adolescence (Mage = 13.21, SD = 3.47) by self- and parent-report, and adult depressive symptoms were assessed up to five times, up to 38 years later. Multilevel modeling was used to examine the effect of adolescent peer dysfunction on adult depressive symptoms after adjusting for familial confounds and/or individual characteristics in adolescence (e.g., baseline depressive symptoms, dysfunctional relations with siblings/parents). Both self-reported (b = 1.28, p < 0.001) and parent-reported (b = 0.56, p = 0.032) adolescent peer dysfunction were associated with greater depressive symptom severity in adulthood in unadjusted models. Self-reported (but not parent-reported) adolescent peer dysfunction continued to predict adult depressive symptoms after controlling for familial confounding and measured covariates such as adolescent depressive symptoms and relations with siblings and parents (b = 1.06, p = 0.035). Although confidence intervals were wide and the potentially confounding effects of numerous individual-level factors were not ruled out, these findings provide preliminary evidence that perceived peer dysfunction in adolescence may be an unconfounded risk factor for depressive symptoms in adulthood.

Depression over Time in Persons with Stroke: A Network Analysis Approach.

BACKGROUND: Network analysis has been used to elucidate the relationships among depressive symptoms, but this approach has not been typically used in persons with stroke. METHOD: Using a sample of 835 persons with stroke from Stroke Recovery in Underserved Populations 2005-2006 dataset, this study used network analysis to (1) examine changes in relationships between depressive symptoms over time, and (2) test whether baseline network characteristics were prognostic for depression persistence. Network analysis was performed on depressive symptoms collected at discharge from inpatient rehabilitation and at 3-months and 12-months post-discharge. RESULTS: The depressive symptom network at discharge was less connected than at both post-discharge follow-ups. Trouble focusing and feeling good as others were the most predictable symptoms at post-discharge, even though they were less connected to other depressive symptoms. Among participants with elevated baseline depression severity, those whose depression persisted 12 months later had more strongly connected networks at discharge than those who recovered 12 months later. LIMITATIONS: This study was unable to determine the directionality of edges. The depression scale was administered differently across time points. CONCLUSION: These results suggest that baseline network connectivity can predict the course of post-stroke depression, similar to non-stroke populations. More broadly, the study highlights the importance of examining relationships between individual depressive symptoms rather than only sum-scores.

Internal Consistency and Convergent Validity of Self-Report and By-Proxy Measures of Depression in Persons With Aphasia.

Purpose Depression assessment is challenging in persons with aphasia given their language impairment. Studies have used both self-report scales and by-proxy measures of depression in persons with aphasia. However, the validity of these measures has been called into question. The aim of this study was to conduct a preliminary investigation into aspects of validity of the community version of the Stroke Aphasia Depression Questionnaire (SADQ-10) and the Center for Epidemiological Studies Depression Scale-Revised (CESD-R). Method Twenty-four participants with chronic aphasia completed the CESD-R, the Patient-Reported Outcomes Measurement Information System Global Mental Health scale (PROMIS GMH), and the Dynamic Visual Assessment of Mood Scales (D-VAMS) while their caregivers completed the SADQ-10. Internal consistency of the CESD-R and the SADQ-10 and the convergent validity of the CESD-R, SADQ-10, PROMIS GMH, and D-VAMS were examined. Results The SADQ-10 and the CESD-R were internally consistent. The CESD-R was moderately correlated with the SADQ-10, PROMIS GMH, and D-VAMS. However, the SADQ-10 was not correlated with the PROMIS GMH and D-VAMS. Conclusions We suggest both the CESD-R and the SADQ-10 be used together to screen for depression in persons with aphasia. Further studies with larger sample sizes need to be conducted to establish validity of other depression screening instruments in person with aphasia.

Eye Tracking as a Tool to Identify Mood in Aphasia: A Feasibility Study.

Background. Persons with aphasia often present with low mood/depression, which can negatively affect their quality of life. The validity and reliability of existing depression measures for aphasia have been called into question. Eye tracking in nonstroke populations is reliable in identifying low mood/depression. Depressed persons are biased to negative emotions compared with nondepressed persons and have an absence of bias to positive emotions. However, nondepressed persons may be biased to positive emotions. Objective. To examine the feasibility of using eye tracking to measure mood in persons with aphasia. Methods. We recruited 22 persons with chronic aphasia and 12 healthy controls. Participants completed 2 self-report measures of mood. They also viewed faces that showed happy, sad, and neutral facial expressions during eye tracking. We analyzed 2 eye tracking indices: initial gaze orientation and gaze maintenance to happy, sad, and neutral faces. Results. For initial gaze orientation, participants with aphasia fixated faster on emotional faces compared with healthy controls but directed their gaze less often to happy faces compared with healthy controls. For gaze maintenance components, the duration of first fixation and total fixation duration were shorter on sad faces for participants with aphasia compared with healthy controls. Conclusion. Use of eye tracking with faces representing different mood states is feasible in persons with aphasia. Although there were some similarities, participants with aphasia had different gaze patterns to emotional faces compared with healthy controls. Further research is needed to establish whether this is a valid and reliable method of mood assessment.

Depression and Subthreshold Depression in Stroke-Related Aphasia.

OBJECTIVE: To investigate the prevalence of depression and subthreshold depression in persons with aphasia. To investigate whether there are linguistic and cognitive differences between those with depression, subthreshold depression, and no depression. DESIGN: Survey. SETTING: Rehabilitation hospital. PARTICIPANTS: Participants with chronic aphasia due to a single left-hemisphere stroke (N=144). MAIN OUTCOME MEASURES: Center for Epidemiologic Studies Depression Scale to assess the prevalence of depression. The Western Aphasia Battery-Revised (WAB-R) to evaluate the type of aphasia; the Aphasia Quotient measured the severity of linguistic deficits. RESULTS: The prevalence of depression in our participants was 19.44% while that of subthreshold depression was 22.22%. Depressed persons with aphasia had significantly lower WAB-R reading scores than those without depression. CONCLUSIONS: Findings suggest that persons with aphasia who have depressive symptoms may do worse on some linguistic measures than those with no depression. Since subthreshold depression can progress to depression, clinicians should routinely screen for depressive symptoms.

Frontotemporal stimulation modulates semantically-guided visual search during confrontation naming: A combined tDCS and eye tracking investigation.

Transcranial direct current stimulation (tDCS) was paired with eye tracking to elucidate contributions of frontal, temporoparietal and anterior temporal cortex to early visual search patterns during picture naming (e.g., rapid visual scanning to diagnostic semantic features). Neurotypical adults named line drawings of objects prior to and following tDCS in three separate sessions, each employing a unique electrode montage. The gaze data revealed montage by stimulation (pre/post) interaction effects characterized by longer initial visual fixations (mean difference = 89 ms; Cohen's d = .8) and cumulative fixation durations (mean difference = 98 ms; Cohen's d = .9) on key semantic features (e.g., the head of an animal) after cathodal frontotemporal stimulation relative to the pre-stimulation baseline. We interpret these findings as reflecting a tDCS-induced modulation of semantic contributions of the anterior temporal lobe(s) to top-down influences on object recognition. Further, we discuss implications for the optimization of tDCS for the treatment of anomia in aphasia.

Cathodal tDCS of the bilateral anterior temporal lobes facilitates semantically-driven verbal fluency.

In a verbal fluency task, a person is required to produce as many exemplars of a given category (e.g., 'animals', or words starting with 'f') as possible within a fixed duration. Successful verbal fluency performance relies both on the depth of search within semantic/phonological neighborhoods ('clustering') and the ability to flexibly disengage between exhausted clusters ('switching'). Convergent evidence from functional imaging and neuropsychology suggests that cluster-switch behaviors engage dissociable brain regions. Switching has been linked to a frontoparietal network dedicated to executive functioning and controlled lexical retrieval, whereas clustering is more commonly associated with temporal lobe regions dedicated to semantic and phonological processing. Here we attempted to modulate cluster-switch dynamics among neurotypical adults (N = 24) using transcranial direct current stimulation (tDCS) delivered at three sites: a) anterior temporal cortex; b) frontal cortex; and c) temporoparietal cortex. Participants completed letter-guided and semantic category verbal fluency tasks pre/post stimulation. Cathodal stimulation of anterior temporal cortex facilitated the total number of words generated and the number of words generated within clusters during semantic category verbal fluency. These neuromodulatory effects were specific to stimulation of the one anatomical site. Our findings highlight the role of the anterior temporal lobes in representing semantic category structure and support the claim that clustering and switching behaviors have distinct substrates. We discuss implications both for theory and application to neurorehabilitation.