Hemispatial neglect

When visual neglect is a perception disorder ( Contidex ) in the form of neglect of a room or part of the body ( egocentric ) and / or object halves ( allocentrically ). There is a related to vision special form of Neglects.

Symptoms

Patients with visual neglect neglect one half of their perceptual field, which - depending on the lesion side - located either on the left or right of the fixation point. A very important feature of this disorder is that the patient does not perceive this limitation. He may not realize is that it neglects one half of the room, even if one presents him repeatedly experimental evidence of its capabilities. This is an important distinguishing criterion to visual field defects (see hemianopsia, scotoma ): In these cases, the patient is blind in parts of his vision, he takes this limitation but true. Visual field defects also go back to causes other than the neglect.

Some exemplary egocentric (on one's own body axis ) and allocentric ( object to the general page ) manifestations of the visual Neglects:

  • The food the patient eats only from that side dish he did not neglected. He can completely unnoticed This other side. One rotates the plate by 180 ° so that the rendered page is located in the field of perception, the patient eats that half the meal. Nevertheless, he can not perceive his fault. Substituting the patients with left-sided neglect, for example, a plate in front, on the left side, only potatoes and vegetables and meat are just right, so the patient complained that he receives no potatoes to the meal.
  • Patients wash and shave only one side of the body.
  • If you show patients images of faces, which consist of two different halves of the face (eg left half and right half of Bill Clinton Elvis Presley ) as passed to the patient that full face of the person to see whose face is on their perceived side.
  • You put the patient in front of a sheet of paper with many horizontal lines and asks him to divide each of the lines exactly by a vertical line in the middle. Firstly, the patient worked only those horizontal lines that are in its field of perception ( and will still indicate to have met the task). On the other hand it tends to slightly shift the vertical lines at each horizontal line in the direction of his perceptual field, rather than draw in the middle.
  • If the patient is a picture or photo looming, it records only the perceived half.
  • If the patient draw a watch face, he paints in general, although a complete circle, but records every 12 hours markings only on its perceived object side.
  • The patient is shown the sketched image of a flower. The flower has ever branch off a thick stem, from the left and on the right a large blooms. If the patient zweiblütige this plant emerge, he sketched only one of the two flowers and neglects the second. If the experimenter but the thick stems of the flower covered, and thus the common origin of the two flowers is obscured, so the patient takes both flowers true - however drawing from each flower only the perceived one half. The resulting limitations in daily life can be significant and affect all other therapies such as physiotherapy rehabilitation of other disorders ( paralysis, etc.) strongly or even impossible. A particular problem often proves the simultaneous presence of a visual or multimodal Neglects and a visual field loss.

Causes

The visual neglect is not - while vermutbar - of harm to the primary visual system back. With neglect patients without Sehfeldverlust both the optical paths, as well as the visual cortex, the occipital lobe are not damaged. For a visual neglect it comes rather by a lesion in the parietal lobe of the cortex. In this area of ​​the brain localized to the attention control. With the help of imaging techniques, it was found that especially the right parietal hemisphere is responsible for attentional control in most people. It leads you back that most neglect patients have a left-side Neglect:

The left field of perception is controlled by the right hemisphere. When damage to the right Paritellappens this important control system fails. When damage to the left parietal cortex ( which controls the right field of perception ), one observes, however, only a slight neglect on the right side of the face. This is attributed to the fact that attention is controlled mainly by the intact right hemisphere and thus this can compensate for the left-sided lesion partially.

Forms of visual field defects are:

  • Hemianopia ( half-side failure)
  • Quadrantenanopsie
  • Scotoma

Another central visual disturbance is:

  • Cortical blindness

There are in the field of clinical neuropsychology different treatment approaches of visual Neglects. In addition to the exploration training stimulation of the neck muscles, optokinetic stimulation therapy and a prism therapy can be successfully applied.

Other special forms of Neglects

  • Olfactory Neglect - Smell
  • Somatosensory neglect - sense of touch
  • Auditory Neglect - Listen
Field of view Medical imaging Quadrantanopia
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