The relationship between short-term memory, conflict resolution, and sentence comprehension impairments in aphasia

ABSTRACT

Background: Sentence comprehension involves the integration of multiple linguistic representations. This integration can be especially challenging when different cues lead to conflicting interpretations. Short-term memory (STM) and conflict resolution are two processes that have been previously linked to sentence comprehension and could assist in integration. However, the relation of each process to comprehension independently of the other has not been fully clarified.

Aims: We tested two patients with contrasting STM and conflict resolution profiles in different sentence comprehension tasks to evaluate the relationship between the three abilities.

Methods & Procedures: Patients completed (a) six STM tasks that tested either span or updating; (b) two executive function tasks that tested conflict resolution; and (c) three tasks that evaluated sentence comprehension.

Outcomes & Results: The patient with poorer STM and better conflict resolution had variable success in sentence comprehension that was contingent on memory load and the extent to which interpretation was supported by semantic knowledge. In contrast, the patient with good STM but slow conflict resolution demonstrated accurate comprehension across all tasks and conditions, and delayed reaction times for sentences containing conflict between cues.

Conclusions: The results provide broad support for a link between STM and sentence comprehension. They suggest that inefficient conflict resolution might be associated with slowed down but not inaccurate comprehension of sentences when other abilities, including STM, are intact. We discuss the ways in which STM and conflict resolution may and may not assist sentence comprehension in individuals with aphasia.

KEYWORDS:

• STM
• executive function
• cognitive control
• aphasia
• sentence processing

Acknowledgments

We thank the patients for their participation in the study, and Michelle Rattinger and Christine Asaro for stimulus preparation and data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.