Eye Movements during Measurements of Visual Vertical in the Poststroke Subacute Phase

Area of Science:

• Neuroscience
• Ophthalmology
• Cognitive Psychology

Background:

• The subjective visual vertical (VV) is crucial for vestibular function and visuospatial cognition.
• Unilateral spatial neglect (USN) significantly impacts spatial awareness and orientation.
• Understanding the mechanisms of altered VV perception in USN is vital for effective rehabilitation.

Purpose of the Study:

• To investigate the relationship between eye movement patterns and VV perception in stroke patients with USN.
• To identify specific visual scanning behaviors associated with impaired VV judgments in USN.
• To explore the role of frontal lobe function in VV perception within the USN population.

Main Methods:

• Participants with and without USN performed VV judgment tasks involving a rotating bar.
• Eye movement patterns, including fixation points and scanning range, were meticulously recorded.
• Correlation analysis examined the link between scanning behavior and VV accuracy.

Main Results:

• USN participants exhibited restricted eye scanning, fixating on prominent bar ends, unlike controls with central scanning.
• Accurate VV judgments in some USN patients without frontal lesions correlated with broader scanning including the bar's center.
• Fixation on peripheral, salient areas and frontal lobe involvement in attention shifting were identified as key factors.

Conclusions:

• Altered VV perception in USN is linked to a bias towards peripheral visual fixation and difficulties in attentional disengagement.
• Targeted rehabilitation focusing on expanding visual scanning to include central areas shows promise for improving VV accuracy in USN.
• This research underscores the importance of specific eye movement strategies in understanding and treating visuospatial deficits.