436 Neuroanatomy: Draw It to Know It
Apraxia & Neglect ( Advanced ) (Cont.)
Now, in regards to neglect, in the right cerebral hemi-
sphere, draw the intraparietal sulcus and label the infe-
rior parietal lobule as the site for hemispatial neglect.
Hemispatial neglect involves a lack of regard for objects
in the contralateral hemisphere. It may be as mild as to
cause extinction to double simultaneous stimulation,
meaning that patients will perceive a sensory stimulus on
the left side when it is presented only to that side and
neglect the stimulus when it is presented to both sides.
Or it may be as severe as to cause failure to attend to the
left half of the world, entirely.^21
Finally, show that large right parietal lobe injuries can
cause anosognosia, which is a lack of awareness of the
presence of a defi cit. When anosognosia accompanies
occipital lobe injury, which results in a visual fi eld defi -
cit, patients may display a denial of their own blindness,
called Anton syndrome. In a separate form of lack of
awareness, patients may demonstrate autotopagnosia,
which manifests with an unawareness of one’s own body
parts; for instance, in right hemispheric strokes with
hemispatial neglect, patients with autotopagnosia may
insist that their left hand is not their own but is instead
the examiner’s hand. Note that autotopagnosia can occur
as a more restricted clinical phenomenon (separate from
a broad neglect injury).^25 , 26