title: Eye movement and online bisection task in unilateral patients with neglect: a new look to the 'gradient effect'.
abstract: OBJECTIVE
  The present study explored the behavioural and eye-movement measures in spatial unilateral neglect in response to a bisection task.
  
  
  METHODS
  Four right neglect patients were considered and compared with 11 control subjects during an online task (segment bisection).
  
  
  METHODS
  Eye-movements (fixation count and duration) and behavioural responses were monitored during an online bisection task, consisting of unfilled segments (two ending points) to be bisected by subjects. Segment length (six levels) and spatial dislocation (five levels) were modulated to explore a possible 'gradient effect'" (left-to-right) in neglect bias.
  
  
  RESULTS
  Consistent spatial biases were found for both bisection position and eye fixations as a function of segment length (from shorter to longer) and segment spatial dislocation (from right to left). However, only the more eccentric left-positions induced a greater rightward bias in patients, with increasing more right-side bisection and visual right-directed fixations. Also segment length produced significant differences between-groups for behavioural responses, with more right-side bisection for longer segment in patients, and eye movement behaviour, with increased fixation count and duration rightward oriented in response to longer segments.
  
  
  CONCLUSIONS
  Although a left-to-right and longer-to-shorter 'continuous-gradient effect' was not supported by the results, an 'extreme left-gradient effect' was suggested and discussed.
authors: Laboratory of Cognitive Psychology and Neuroscience, Department of Psychology, Catholic University of Milan, Largo Gemelli, 1, 20123 Milan, Italy. michela.balconi@unicatt.it
authors: Michela
authors: M
authors: Balconi
authors: Simona
authors: S
authors: Amenta
authors: Matteo
authors: M
authors: Sozzi
authors: Anna Paola
authors: AP
authors: Cannatà
authors: Luigi
authors: L
authors: Pisani
mesh_terms: D000368:Aged; D005133:Eye Movements; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual; D010468:Perceptual Disorders / Q000503:physiopathology*; D011597:Psychomotor Performance; D015203:Reproducibility of Results; D013028:Space Perception; D013647:Task Performance and Analysis; D014794:Visual Fields; D014796:Visual Perception