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

Area of Science:

• Neuroscience
• Cognitive Psychology
• Speech and Language Pathology

Background:

• Executive control is crucial for frontal lobe function.
• Aphasia, often resulting from frontal lesions, may impact executive control.
• Previous research has inconsistently measured executive control in aphasia, often overlooking language demands.

Purpose of the Study:

• To investigate executive control performance in individuals with aphasia.
• To compare performance on low-verbal versus high-verbal executive control tasks.
• To examine the impact of verbal load on executive control in aphasia.

Main Methods:

• Ten participants with aphasia (left inferior frontal lesions) and 15 age-matched controls completed executive control tasks.
• Tasks assessed inhibition, switching, and updating of working memory.
• Tasks were administered in both low-verbal and high-verbal versions.

Main Results:

• No consistent effect of verbal load on reaction time or accuracy was observed in either group.
• Participants with aphasia exhibited slower reaction times across all tasks compared to controls.
• Aphasia was associated with lower accuracy on switching and updating tasks.

Conclusions:

• Executive control deficits in aphasia are not solely dependent on language processing demands.
• Switching and updating working memory tasks are particularly challenging for individuals with aphasia.
• Frontal lobe damage in aphasia significantly impacts core executive functions.