The perception of peripersonal space in right and left brain damage hemiplegic patients.
Peripersonal space, as opposed to extrapersonal space, is the space that contains reachable objects and in which multisensory and sensorimotor integration is enhanced. Thus, the perception of peripersonal space requires combining information on the spatial properties of the environment with information on the current capacity to act. In support of this, recent studies have provided converging evidences that perceiving objects in peripersonal space activates a neural network overlapping with that subtending voluntary motor action and motor imagery. Other studies have also underlined the dominant role of the right hemisphere (RH) in motor planning and of the left hemisphere (LH) in on-line motor guiding, respectively. In the present study, we investigated the effect of a right or left hemiplegia in the perception of peripersonal space. 16 hemiplegic patients with brain damage to the left (LH) or right (RH) hemisphere and eight matched healthy controls performed a color discrimination, a motor imagery and a reachability judgment task. Analyses of response times and accuracy revealed no variation among the three groups in the color discrimination task, suggesting the absence of any specific perceptual or decisional deficits in the patient groups. In contrast, the patient groups revealed longer response times in the motor imagery task when performed in reference to the hemiplegic arm (RH and LH) or to the healthy arm (RH). Moreover, RH group showed longer response times in the reachability judgment task, but only for stimuli located at the boundary of peripersonal space, which was furthermore significantly reduced in size. Considered together, these results confirm the crucial role of the motor system in motor imagery task and the perception of peripersonal space. They also revealed that RH damage has a more detrimental effect on reachability estimates, suggesting that motor planning processes contribute specifically to the perception of peripersonal space.
Laboratoire Unité de Recherche en Sciences Cognitives et Sciences Affectives, Université Lille Nord de France Lille, France.
Angela
A
Bartolo
Laboratoire Unité de Recherche en Sciences Cognitives et Sciences Affectives, Université Lille Nord de France Lille, France.
Mauraine
M
Carlier
Service de Neuropsychologie, Centre de rééducation et de réadaptations fonctionnelles spécialisées - Sainte Barbe, Fouquières les Lens France.
Sabrina
S
Hassaini
Service de Neuropsychologie, Centre de rééducation et de réadaptations fonctionnelles spécialisées - L'Espoir, Hellemmes France.
Yves
Y
Martin
Laboratoire Unité de Recherche en Sciences Cognitives et Sciences Affectives, Université Lille Nord de France Lille, France.
Yann
Y
Coello
brain damage; perception and action; peripersonal space; right left hemispheres; spatial vision