Tuesday, October 27, 2009

Hemispatial Neglect

Hemispatial neglect is a neuropsychological condition which is characterized, after damage to one hemisphere of the brain, by an attentional deficit and awareness of one side of space. Although hemispatial neglect is very commonly contralateral to the damaged hemisphere, instances of ipsilesional neglect have been reported.

In other words, hemispatial neglect is a neurological disorder which is defined as a lack of attention for stimuli contra-lateral to the brain lesion. The assessment is traditionally done with basic pencil and paper tests and the rehabilitation programs are generally not well adapted. We propose a virtual reality system featuring an eye-tracking device for a better characterization of the neglect that will lead to new rehabilitation techniques. A stroke affecting the right parietal lobe of the brain can lead to neglect for the left side of the visual field, causing a patient with neglect to behave as if the left side of sensory space is nonexistent; although they can still turn left. In an extreme case, a patient with neglect might fail to eat the food on the left half of their plate, even though they complain of being hungry.

In hemispatial neglect there is a failure to represent information appearing in the hemispace contralateralto a brain lesion. In addition to the perceptual consequences of hemispatial neglect, several authors have reported that hemispatial neglect impairs visually guided movements. In some cases, neglect has been shown to impair visual perception without affecting visuomotor control in relation to the very same stimuli.