Task-Related Differences in Eye Movements in Individuals With Aphasia

Area of Science:

• Neuroscience
• Ophthalmology
• Speech and Language Pathology

Background:

• Neurotypical individuals exhibit task-based modulation and stability in eye movements.
• Previous research has not fully explored if persons with aphasia (PWA) display similar eye movement modulation and stability across tasks.

Purpose of the Study:

• To investigate whether persons with aphasia (PWA) modulate their eye movements and maintain stability across different tasks similarly to control participants.
• To identify potential differences in eye movement patterns between PWA and controls, and to explore how these patterns vary across different cognitive tasks.

Main Methods:

• Forty-eight PWA and age-matched controls participated in the study.
• Participants completed four eye-tracking tasks: scene search, scene memorization, text-reading, and pseudo-reading.
• Eye movement metrics including mean fixation duration and saccade amplitude were analyzed.

Main Results:

• Significant task-based modulation of eye movements was observed in both groups.
• PWA exhibited shorter fixation durations and smaller saccade amplitudes compared to controls, especially in scene memorization and text-reading tasks.
• Aphasia subtype and recency of stroke influenced eye movement patterns, with anomic aphasia showing reduced saccade modulation in reading and conduction/Wernicke's aphasia showing shorter fixations in memorization.

Conclusions:

• Persons with aphasia (PWA) demonstrate task-based eye movement modulation, although patterns differ from controls, particularly in reading and scene memorization.
• Eye movement analysis shows potential for differentiating PWA subtypes and assessing recovery post-stroke.
• Fixation duration remained stable across tasks for both PWA and controls, suggesting preserved temporal stability despite other observed differences.