What do eye-fixation patterns tell us about unilateral spatial neglect?
OBJECTIVE
Eye-fixation patterns, which include ocular searching and fixation, may change with tasks, stimuli, and instructions. This article reviews our studies over 18 years on eye-fixation patterns of neglect patients and aims to elucidate the visuospatial processing of unilateral spatial neglect.


METHODS
We recorded eye-fixation patterns when patients with neglect bisected a line in various conditions.


RESULTS
Patients with neglect rarely searched to the left side when bisecting a line of the ordinary length (e.g., 200 mm). They persisted in fixating a right-side point, at which they later marked the subjective midpoint. They made no effective comparison between the leftward and rightward extents not only for a whole line but also for its explored right segment. Where they 'favored' to fixate as the subjective midpoint depended strongly upon the location of the right endpoint in space. Their representational image of a line was also estimated with modified line bisection tasks performed on a touch-panel display.


CONCLUSIONS
For patients with neglect, the representational image of a line may be formed on the basis of the attended segment between the right endpoint and the favored point of fixation. The line bisection task, if combined with recording of eye-fixation, would further contribute to elucidation of the mechanisms underlying neglect.
Ishiai
Sumio
S
Department of Rehabilitation, Sapporo Medical University, School of Medicine, Sapporo, Japan. ishiai@sapmed.ac.jp
D003463:Cues; D005403:Fixation, Ocular / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000503:physiopathology*