Eye-movements and bisection task in neglect syndrome. Segment length and spatial dislocation effect

The present research explored spatial attentional deficit in one patient with unilateral neglect syndrome. Bisection responses and eye-movements (fixation count and fixation length) were monitored when subjects (one patient and 10 control subjects) executed online a spatial tasks, that is the bisection of a “virtual” segment (defined by the two ending points). Segments differed in length (5 levels, from short to long) and spatial localization (6 levels, from the left side of the visual field to the right side). Different bisection responses and eye-movements behavior were observed between patient and control subjects. Patient showed an anomalous bisection response (spatial bias) as a function of segment length and dislocation, with an increased difficulties in bisection for longer segments (higher RTs). In addition, anomalous eye movements, with an increased right-side bias, were revealed for neglect patient. In general, less and longer fixations were revealed in comparison with control subjects. The integration of behavioral and eye-movement measures was discussed, in order to identify anomalies in spatial attention and attentional strategies.