title: Different visual exploration of tool-related gestures in left hemisphere brain damaged patients is associated with poor gestural imitation.
abstract: According to the direct matching hypothesis, perceived movements automatically activate existing motor components through matching of the perceived gesture and its execution. The aim of the present study was to test the direct matching hypothesis by assessing whether visual exploration behavior correlate with deficits in gestural imitation in left hemisphere damaged (LHD) patients. Eighteen LHD patients and twenty healthy control subjects took part in the study. Gesture imitation performance was measured by the test for upper limb apraxia (TULIA). Visual exploration behavior was measured by an infrared eye-tracking system. Short videos including forty gestures (20 meaningless and 20 communicative gestures) were presented. Cumulative fixation duration was measured in different regions of interest (ROIs), namely the face, the gesturing hand, the body, and the surrounding environment. Compared to healthy subjects, patients fixated significantly less the ROIs comprising the face and the gesturing hand during the exploration of emblematic and tool-related gestures. Moreover, visual exploration of tool-related gestures significantly correlated with tool-related imitation as measured by TULIA in LHD patients. Patients and controls did not differ in the visual exploration of meaningless gestures, and no significant relationships were found between visual exploration behavior and the imitation of emblematic and meaningless gestures in TULIA. The present study thus suggests that altered visual exploration may lead to disturbed imitation of tool related gestures, however not of emblematic and meaningless gestures. Consequently, our findings partially support the direct matching hypothesis.
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland; Neurology and Neurorehabilitation Center, Luzerner Kantonsspital, Switzerland.
authors.forename: Tim
authors.initials: T
authors.lastname: Vanbellingen
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland; Division of Cognitive and Restorative Neurology, Department of Neurology, Inselspital, Bern University Hospital, and University of Bern, Switzerland.
authors.forename: Rahel
authors.initials: R
authors.lastname: Schumacher
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland.
authors.forename: Noëmi
authors.initials: N
authors.lastname: Eggenberger
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland.
authors.forename: Simone
authors.initials: S
authors.lastname: Hopfner
authors.affiliation: Nuffield Department of Clinical Neurosciences, Clinical Neurology, University of Oxford, Oxford, United Kingdom.
authors.forename: Dario
authors.initials: D
authors.lastname: Cazzoli
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland.
authors.forename: Basil C
authors.initials: BC
authors.lastname: Preisig
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland.
authors.forename: Manuel
authors.initials: M
authors.lastname: Bertschi
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland; Neurology and Neurorehabilitation Center, Luzerner Kantonsspital, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nyffeler
authors.affiliation: Division of Cognitive and Restorative Neurology, Department of Neurology, Inselspital, Bern University Hospital, and University of Bern, Switzerland.
authors.forename: Klemens
authors.initials: K
authors.lastname: Gutbrod
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland.
authors.forename: Claudio L
authors.initials: CL
authors.lastname: Bassetti
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland; Neurology and Neurorehabilitation Center, Luzerner Kantonsspital, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Bohlhalter
authors.affiliation: Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, Switzerland; Division of Cognitive and Restorative Neurology, Department of Neurology, Inselspital, Bern University Hospital, and University of Bern, Switzerland; Gerontechnology and Rehabilitation Group, University of Bern, Bern, Switzerland; Center for Cognition, Learning and Memory, University of Bern, Bern, Switzerland. Electronic address: Rene.mueri@insel.ch.
authors.forename: René M
authors.initials: RM
authors.lastname: Müri
mesh_terms: D000328:Adult; D000368:Aged; D053483:Eye Movement Measurements; D005133:Eye Movements; D005260:Female; D007839:Functional Laterality; D005868:Gestures; D006801:Humans; D007100:Imitative Behavior; D007259:Infrared Rays; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009039:Motion Perception; D010364:Pattern Recognition, Visual; D020521:Stroke / Q000473:pathology / Q000523:psychology; D014057:Tomography, X-Ray Computed; D014741:Video Recording; D055815:Young Adult
keywords: Eye movements; Gesture perception; Imitation; Visual exploration