Hemispatial neglect
From Wikipedia, the free encyclopedia
Hemispatial neglect, also called unilateral neglect, spatial neglect or neglect syndrome is a neurological condition in which, after damage to the posterior parietal lobe, a deficit in attention to the opposite side of space is observed. Damage to 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. For example, patients with neglect will often fail to eat the food on the left half of their plate, even though they complain of being hungry. If someone with neglect is shown a clock and asked to draw it, the drawing will show only the numbers 12 and 1 to 6, the other side being shrunken and essentially blank. Damage to adjacent regions of the brain can lead to neglect of parts of tactile and kinesthetic space. Someone with this form of neglect might treat his or her own leg as not belonging to his or her own body (called anosognosia).
Damage associated with the brain areas in the temporal, parietal and frontal lobes is associated with the deployment of attention (through eye movements, head turns or limb reaches) into left or right space. Neglect is most closely related to damage to the temporo-parietal junction and posterior parietal cortex. The lack of attention to the left side of space can manifest in the visual, auditory, proprioceptive, and olfactory domains. Although hemispatial neglect often manifests as a sensory deficit (and is frequently co-morbid with sensory deficit), it is essentially a failure to pay sufficient attention to sensory input. This is particularly evident in a related phenomenon known as extinction. Extinction is evident where a patient will report the presence of an object in left space when it is the only object present. If the same object is presented simultaneously with an object in right space, the patient will only report the object on the right. Hemispatial neglect is most common after right-hemisphere stroke, but has been identified following left-hemisphere stroke as well (left-hemisphere stroke results in the neglect of the right side of space).
Behaviours associated with neglect include failure to find objects on the left side of a table or in a room, sometimes meaning patients with stroke will only eat food from the right side of a plate, wash or shave only the right half of their face or bump into things on the left side when walking or moving in a wheelchair. Rehabilitation of neglect is often carried out by neuropsychologists and occupational therapists.
[edit] See also
[edit] References
Hans-Otto Karnath, A. David Milner, and Giuseppe Vallar (2002) The Cognitive and Neural Bases of Spatial Neglect. (SBN-10: 0-19-850833-6)
Robertson, I.H., & Halligan, P.W. (1999). Spatial neglect: A clinical handbook for diagnosis and treatment. Hove, East Sussex:Erlbaum.de:Visueller Neglect fr:Héminégligence it:Negligenza spaziale unilaterale is:Gaumstol
