Lower-level oculomotor deficits in schizophrenia during multi-line reading: Evidence from return-sweeps

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Reading fluency deficits are common in schizophrenia (Sz).
• These deficits are often attributed to impaired lower-level oculomotor and higher-level lexical processing.
• Previous research focused on single-line/word tasks, neglecting passage-specific eye movements like return-sweep saccades.

Purpose of the Study:

• To investigate the role of oculomotor control in reading deficits in schizophrenia.
• To examine return-sweep saccades, which are crucial for natural passage reading.
• To test the two-hit deficit model by assessing lower-level processing during reading.

Main Methods:

• Analysis of an existing dataset of participants reading multi-line passages.
• Manipulation of line spacing to assess visual crowding effects.
• Measurement of return-sweep saccade accuracy and fixation durations.

Main Results:

• Individuals with schizophrenia made significantly more return-sweep targeting errors and corrective saccades than healthy controls.
• Both groups showed similar sensitivity to line spacing, indicating comparable visual crowding effects.
• Fixation patterns in schizophrenia suggested reduced parafoveal processing of upcoming words.

Conclusions:

• Lower-level oculomotor dysfunction contributes to reading deficits in schizophrenia.
• Findings support the two-hit deficit model by highlighting the impact of oculomotor impairments.
• Return-sweep saccade analysis offers a novel method for studying reading in schizophrenia.