Eyes on the Pupil Size: Pupillary Response During Sentence Processing in Aphasia

Area of Science:

• Neuroscience
• Psycholinguistics
• Speech and Language Pathology

Background:

• Individuals with chronic agrammatic aphasia experience real-time sentence processing deficits at lexical and structural levels.
• Previous research links these difficulties to delayed semantic representation access during sentence construction.
• Pupillometry offers a sensitive measure of real-time cognitive processing effort.

Purpose of the Study:

• To investigate real-time processing effort in individuals with aphasia and controls during sentence comprehension.
• To determine if semantically biased lexical cues (adjectives) influence processing effort in complex sentences.
• To assess the role of pupillometry in measuring sentence processing in aphasia.

Main Methods:

• An eye-tracking while listening study with a within-subjects design was employed.
• Participants listened to sentences with either biased or unbiased adjectives while viewing images.
• Pupillary responses were continuously recorded throughout sentence presentation.

Main Results:

• Control participants showed increasing pupil responses, while individuals with aphasia exhibited an early plateau.
• Both groups demonstrated reduced processing effort when presented with biased adjectives.
• This suggests that lexical-semantic cues can modulate processing load.

Conclusions:

• Individuals with aphasia are sensitive to lexical-semantic cues, even with impaired real-time lexical activation.
• Semantic bias in adjectives can reduce cognitive load during sentence processing for both aphasia patients and controls.
• Pupillometry is a viable tool for assessing sentence processing in individuals with aphasia.