title: Selective improvement of anosognosia for hemiplegia during transcranial direct current stimulation: a case report.
abstract: Right brain damage patients may not complain of a left sided paralysis up to the point of denying it or even claiming of having just moved an otherwise paralyzed limb. This condition is known as anosognosia for hemiplegia (AHP). Recent behavioural experiments suggest that some residual intentionality might be preserved in patients with anosognosia and that the false belief of having moved originates from a failure to notice discrepancies between movement expectancies and the actual state of the motor system. This failure may be caused by a lack of afferent sensory information concerning the movement or alternatively by a direct dysfunction of the brain regions involved in actions' motor monitoring (i.e., the comparator system). Here we examined the effect of anodal transcranial direct current stimulation (tDCS) of the right premotor cortex in a patient with a bilateral lesion, involving predominantly the right hemisphere, and a dense unawareness for his left hemiplegia. During sham or anodal tDCS the patient was requested to judge his ability to perform simple motor actions (i) without actually executing the movement itself ("offline" condition) and after having performed a series of verbally cued finger opposition movements ("online" condition) with (i) eyes-closed or (ii) eyes-open. We found that anodal tDCS induces a significant remission of the false experience of movement only when the patient is requested to actually perform the movement with eyes open. Conversely, the patient's awareness does not improve in both the "offline" condition (in which the patient does not attempt to perform the movement) and in the "online" condition, when vision is precluded ("online" condition, eyes-closed). We conclude that the stimulation of the premotor cortex by tDCS activates brain regions involved in motor monitoring, temporary restoring the ability of the motor comparator system to correctly appreciate afferent information and build up a veridical motor awareness.
authors.affiliation: Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy. Electronic address: martina.gandola@unipv.it.
authors.forename: Martina
authors.initials: M
authors.lastname: Gandola
authors.affiliation: Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Sedda
authors.affiliation: Psychology Service, Salvatore Maugeri Foundation, IRCCS, Scientific Institute of Pavia, Pavia, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Manera
authors.affiliation: Neurorehabilitation Unit, Salvatore Maugeri Foundation, IRCCS, Scientific Institute of Pavia, Pavia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Pingue
authors.affiliation: Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Salvato
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; Neuropsychology Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy.
authors.forename: Grazia F
authors.initials: GF
authors.lastname: Spitoni
authors.affiliation: Neurorehabilitation Unit, Salvatore Maugeri Foundation, IRCCS, Scientific Institute of Pavia, Pavia, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Pistarini
authors.affiliation: Psychology Service, Salvatore Maugeri Foundation, IRCCS, Scientific Institute of Pavia, Pavia, Italy.
authors.forename: Ines
authors.initials: I
authors.lastname: Giorgi
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; Neuropsychology Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Pizzamiglio
authors.affiliation: Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy; Cognitive Neuropsychology Centre, Niguarda Ca' Granda Hospital, Milano, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Bottini
mesh_terms: D000377:Agnosia / Q000175:diagnosis / Q000628:therapy*; D001364:Awareness / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006429:Hemiplegia / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D065908:Transcranial Direct Current Stimulation
keywords: Anosognosia for hemiplegia; Intention to move; Motor awareness; Neglect; Transcranial direct current stimulation