William D. Hula

Models of attention and dual-task performance as explanatory constructs in aphasia.

Aphasia has traditionally been viewed as a loss or impairment of language. However, evidence is presented suggesting that language mechanisms are fundamentally preserved and that aphasic language behaviors are instead due to impairments of cognitive processes supporting their construction. These processes may be understood as a linguistically specialized attentional system that is vulnerable to competition from other processing domains. We present two models of attention that focus on competition for central processing and discuss findings from dual-task studies of normal and aphasic performance. First, competing language and nonlanguage tasks appear to share limited-capacity, parallel processing resources. Second, aphasic individuals demonstrate slowed central processing that could be due to a reduction in processing capacity or ability to allocate that capacity. Third, the attention models discussed bear a coherent relationship to current models of language processing. Clinical implications of a cognitive processing account of aphasia are also considered.

Verbal working memory and its relationship to sentence‐level reading and listening comprehension in persons with aphasia

Background: Working memory (WM) has gained recent attention as a cognitive construct that may account for language comprehension deficits in persons with aphasia (PWA) (Caspari, Parkinson, LaPointe, & Katz, 1998; Martin, Kohen, & Kalinyak‐Fliszar, 2008; Wright, Downey, Gravier, Love, & Shapiro, 2007). However, few studies have investigated individual differences in performance on sentence comprehension tasks as a function of WM capacity in PWA when WM demands are manipulated. Aims: The purposes of the current study were: (1) to examine the relationships among verbal WM, sentence comprehension, and severity of impairment in PWA and (2) to investigate the differential performance of high versus low verbal WM groups on sentence comprehension tasks in which task demands were manipulated by the length of the sentence stimuli, complexity of syntactic structure, and by presentation method which varied the time over which the linguistic material was available for computation. Methods & Procedures: A total of 20 PWA were divided into high and low WM groups based on a listening version of a WM sentence span task. Each participant completed a listening version (CRTT) and three reading versions (CRTT‐R) of the Computerised Revised Token Test as the sentence comprehension tasks. Outcomes & Results: The WM task significantly predicted performance on the CRTT conditions in which information was only temporarily available, thereby imposing greater WM demands on sentence comprehension. The verbal WM task was significantly correlated with aphasia severity and a principal components analysis revealed that the WM task, overall aphasia severity, and overall reading impairment level loaded on a single factor with 76% of shared variance. The low WM groups performance was significantly lower than the high WM group on the CRTT subtests with syntactically more complex structures and on the CRTT conditions with temporally restricted presentation methods. Conclusions: This verbal WM task was significantly and moderately correlated with the overall severity of aphasia as well as with both listening and reading sentence comprehension. The WM group differences emerged only in sentence comprehension tasks with greater WM demands. These results are consistent with the notion that WM effects are most evident when WM capacity is sufficiently taxed by the task demands (e.g., Caplan & Waters, 1999; Just & Carpenter, 1992).

The Burden of Stroke Scale (BOSS): Validating patient-reported communication difficulty and associated psychological distress in stroke survivors

Background: The Burden of Stroke Scale (BOSS) (Doyle et al., 2002) is a health-status assessment instrument designed to measure patient-reported difficulty in multiple domains of functioning, psychological distress associated with specific functional limitations, and,general well-being in stroke survivors. Aims : This study was designed to examine the discriminative and concurrent validity of the BOSS Communication Difficulty (CD) and Communication-Associated Psychological Distress (CAPD) scales. A secondary purpose was to provide a preliminary examination of the relationships between the BOSS CD and CAPD scales and aspects of subjective well-being, including the frequency with which participants reported experiencing general positive and negative emotional states. Methods & Procedures : The BOSS was administered as a face-to-face interviewer-assisted survey to 281 medically stable, community-dwelling stroke survivors selected from five collaborating centres in the USA. Prior to administration of the BOSS, all subjects were rated for severity of communication impairment using the Boston Diagnostic Aphasia Examination (BDAE) Severity Rating Scale (Goodglass, Kaplan, & Baressi, 2001) and were administered Subtest 8 of the Revised Token Test (RTT), (McNeil & Prescott, 1978). The discriminant validity of the BOSS CD and CAPD scales was examined by comparing scores in stroke survivors with (N = 135) and without (N = 146) communication impairment, and within the communicatively impaired sample when classified according to BDAE ratings and RTT performance. Concurrent validity of the BOSS CD and CAPD scales was examined by correlating BOSS scores with BDAE ratings and RTT performance. Finally, correlations between the BOSS CAPD, BOSS CD, Positive Mood, and Negative Mood scales were calculated. Outcomes & Results : Statistical analyses revealed significant differences between communicatively impaired and non-communicatively impaired subjects on the BOSS CD and CAPD scales, as well as significant differences between communicatively impaired subjects of differing severity levels classified both by BDAE severity ratings and RTT performance. Correlational analyses revealed moderately strong relationships among the BOSS CD scale, BDAE severity ratings, and RTT performance. Finally, correlations among the BOSS CAPD, CD, Positive Mood, and Negative Mood scales revealed true covarying relationships of moderate strength between the BOSS CAPD and CD scales, and also between the CAPD and Negative Mood Scales. Conclusions : These findings provide preliminary support for the discriminant and construct validity of the BOSS Communication Difficulty (CD) and Communication Associated Distress (CAPD) Scales, and provide an empirical rationale for further research into the relationships between functional status, patient-reported health perceptions, and subjective well-being in stroke survivors with communication disorders.

The Burden of Stroke Scale (BOSS) provided valid, reliable, and responsive score estimates of functioning and well-being during the first year of recovery from stroke

AbstractObjectivesTo examine the reliability, validity, and responsiveness of the Burden of Stroke Scale (BOSS).Study designA prospective cohort of stroke survivors were assessed at 3 (T1, T2), 6 (T3), and 12 (T4) months post onset (MPO) of stroke. Test-retest reliability was evaluated by calculating intra-class correlation coefficients (ICCs) between T1 and T2 scale scores. Convergent validity was evaluated by calculating Pearson product moment correlation coefficients between T1 BOSS, Stroke Impact Scale and MOS SF-36 scale scores assessing similar health concepts. Responsiveness was evaluated using a repeated measures ANOVA and the linear trend test in the full study sample and by calculating standardized response means (SRM) and a probability of change statistic,

Description of an Intensive Residential Aphasia Treatment Program: Rationale, Clinical Processes, and Outcomes

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Development and Simulation Testing of a Computerized Adaptive Version of the Philadelphia Naming Test

between T1, T3, and T4 scale scores in participants demonstrating change on external criteria.ResultsICCs ranged from 0.78 to 0.94. Pearson coefficients ranged from −0.57 to −0.86. Moderate to high responsiveness estimates were obtained for 9 of 12 subscales with SRM (

Measuring communicative functioning in community‐dwelling stroke survivors: Conceptual foundation and item development

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