title: Ipsilesional attentional-approach neglect or crossover effect.
abstract: Patients with ipsilateral neglect (IN) bisect lines toward contralesional space. It has been posited that IN might be induced by an attempt at compensation, as part of the crossover effect, where patients with an ipsilesional bias when bisecting long lines, cross over and develop a contralesional bias on short lines or as a release of an approach (grasp) behavior that might be attentional or intentional. To test these alternative hypotheses we had a patient with IN from a right medial frontal lesion bisect lines that contained no cue, a left-sided cue, a right-sided cue, and bilateral cues. If this patient had ipsilateral neglect (IN) because of a crossover effect or compensation, right-sided cues should have influenced bisection more than left-sided cues. We, however, found that only left-sided cues induced a significant change (left-sided deviation) providing support for the attentional-approach (grasp) hypothesis. Further support of this contralesional attentional grasp hypothesis comes from the observation that this patient also had ipsilesional extinction to simultaneous stimuli.
authors.affiliation: Department of Neurology and Center for Neuropsychological Studies, University of Florida College of Medicine, and Neurology Service, Department of Veteran Affairs Medical Center, Gainesville, Florida 32610-0236, USA. drago@neurology.ufl.edu
authors.forename: Valeria
authors.initials: V
authors.lastname: Drago
authors.forename: Yong
authors.initials: Y
authors.lastname: Jeong
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Crucian
authors.forename: David B
authors.initials: DB
authors.lastname: Fitzgerald
authors.forename: Glen R
authors.initials: GR
authors.lastname: Finney
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mizuno
authors.forename: Francesco
authors.initials: F
authors.lastname: Pisani
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Heilman
mesh_terms: D001288:Attention / Q000502:physiology*; D003463:Cues; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000473:pathology / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*