Executive control in frontal lesion aphasia: Does verbal load matter?

Abstract

Executive control impairments in aphasia resulting from frontal lesions are expected, given that integrity of frontal regions is critical to executive control task performance. Yet the consistency of executive control impairments in aphasia is poorly understood. This is due to previous studies using only a brief set of measures or failing to account for the high language processing demands of many executive control tasks. This study investigated performance across a series of specific and broad executive control task, whilst comparing differences between low or high verbal task versions. Ten participants with aphasia secondary to left inferior frontal lesions and fifteen age matched controls completed a battery of verbal and low verbal executive control tasks tapping into the three core domains of inhibiting, switching, and updating of working memory. For both controls and participants with aphasia, there was no consistent influence of verbal load on either reaction time or accuracy performance. When compared to controls, participants with aphasia demonstrate a general slowing of responses across all reaction time tasks, and are less accurate on switching and updating tasks. These findings do suggest that language processing is not essential for executive control task performance, given that verbal load does not matter. Furthermore, tasks which involve holding multiple sources of information in mind, such as during switching or updating, are particularly vulnerable in aphasia.

Motivated semantic control: Exploring the effects of extrinsic reward and self-reference on semantic retrieval in semantic aphasia

“…Similarly, no correlation was found between patients' semantic control composite and the nonverbal Raven's coloured progressive matrices. While these null results may reflect a lack of statistical power, our results are sufficient to show that associations between semantic and executive performance are not confined to tests with verbal requirements, consistent with evidence that executive task performance is independent of verbal demands in aphasia patients with LIFG lesions (Kendrick et al, 2019;see Chapman et al, 2020 for an alternative view).…”

Is there an effect of diglossia on cognition? An investigation of the relationship between diglossia and Executive Functions in young adults.

“…Analyses of accuracy and reaction time (RT) data were run using generalized linear mixed-effects models from the statistical package lme4 (Kendrick et al, 2019), in R studio version (4.0.3). Because reaction times were not normally distributed, they were logtransformed prior to the analysis.…”

“…Flanker and Stroop tasks were administered to measure inhibition, the Color-shape task was administered to measure switching, and finally the Nback task was administered to measure working memory. Tasks were delivered using Eprime 2.0 software (Psychology Software Tools, PA; for more information on the tasks see Kendrick, Robson, & Meteyard, 2019). All tasks were presented in a 15.6-inch computer screen, and all participants were tested in private rooms.…”

What is Functional Communication? A Theoretical Framework for Real-World Communication Applied to Aphasia Rehabilitation

“…Impairments that affect these cognitive resources have been shown to be important contributors to the success of aphasia rehabilitation (e.g., Salis et al, 2017). Research has shown that these cognitive resources are often reduced or impaired for people with aphasia, including executive functions such as cognitive flexibility, switching, and inhibitory control (Chiou & Kennedy, 2009;El Hachioui et al, 2014;Kendrick et al, 2019;Murray, 1999). Flexibility and the ability to switch, for example, using an alternative or additional channel of expression such as gesture during communication (e.g., Purdy & Wallace, 2015;Wallace & Kayode, 2016), are precisely the kinds of skills that will be important for successful situated language use in aphasia rehabilitation.…”