Eye movements in Parkinson's disease during visual search

Area of Science:

• Neuroscience
• Ophthalmology
• Neurology

Background:

• Visual spatial dysfunction is a known complication in Parkinson's disease (PD).
• Understanding visual search deficits and their correlation with eye movement abnormalities is crucial for managing PD-related visual impairments.

Purpose of the Study:

• To investigate visual search behavior in Parkinson's disease patients.
• To determine if deficits correlate with changes in fixational and non-fixational rapid eye movements (saccades).

Main Methods:

• High-resolution video oculography was used to measure eye movements in Parkinson's disease patients and healthy controls.
• Participants viewed blank scenes and complex real-life scenes, including a visual search task with targets in expected and unexpected locations.

Main Results:

• Parkinson's disease patients showed longer initial times to reach regions of interest but comparable overall response times.
• Fixation durations were similar, with a trend towards shorter durations for unexpected targets.
• During blank scene viewing, Parkinson's disease patients exhibited more fixational saccades (larger amplitude) and fewer non-fixational saccades (smaller amplitude).
• In visual search, Parkinson's disease patients made fewer non-fixational saccades, but fixational saccades were larger, particularly for unexpected targets.

Conclusions:

• Visual search behavior is altered in Parkinson's disease, characterized by specific changes in saccadic eye movements.
• These saccadic alterations, especially increased fixational saccade amplitude for unexpected targets, may contribute to visual spatial dysfunction in PD.