title: 'Moving' a paralysed hand: bimanual coupling effect in patients with anosognosia for hemiplegia.
abstract: Selective neurological impairments can shed light on different aspects of motor cognition. Brain-damaged patients with anosognosia for hemiplegia deny their motor deficit and believe they can still move the paralysed limb. Here we study, for the first time, if the anomalous subjective experience that their affected hand can still move, may have objective consequences that constrain movement execution with the opposite, intact hand. Using a bimanual motor task, in which anosognosic patients were asked to simultaneously trace out lines with their unaffected hand and circles with their paralysed hand, we found that the trajectories of the intact hand were influenced by the requested movement of the paralysed hand, with the intact hand tending to assume an oval trajectory (bimanual coupling effect). This effect was comparable to that of a group of healthy subjects who actually moved both hands. By contrast, brain-damaged patients with motor neglect or actual hemiplegia but no anosognosia did not show this bimanual constraint. We suggest that anosognosic patients may have intact motor intentionality and planning for the plegic hand. Rather than being merely an inexplicable confabulation, anosognosia for the plegic hand can produce objective constraints on what the intact hand does.
authors.affiliation: Psychology Department, University of Turin, Via Po 14, Turin, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Garbarini
authors.forename: Marco
authors.initials: M
authors.lastname: Rabuffetti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Piedimonte
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pia
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ferrarin
authors.forename: Francesca
authors.initials: F
authors.lastname: Frassinetti
authors.forename: Patrizia
authors.initials: P
authors.lastname: Gindri
authors.forename: Anna
authors.initials: A
authors.lastname: Cantagallo
authors.forename: Jon
authors.initials: J
authors.lastname: Driver
authors.forename: Anna
authors.initials: A
authors.lastname: Berti
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001364:Awareness; D001930:Brain Injuries / Q000150:complications / Q000209:etiology; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D007839:Functional Laterality; D006225:Hand; D006429:Hemiplegia / Q000150:complications* / Q000209:etiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008609:Mental Status Schedule; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*