- Cognition 427
Apraxia & Neglect ( Advanced )
■ Overall, apraxias are more common with left brain
injuries and neglect is more common with right brain
injuries.
■ Broadly, the frontally based executive apraxias aff ect
movement and the posterior apraxias aff ect sensory
skills and sensorimotor planning.
■ Ideational apraxia is an inability to correctly
conceptualize an action; for instance, patients might
seal an envelope and then try to stuff a letter into it.
■ Ideational apraxia localizes to the left hemispheric
temporoparietal junction.
■ Ideomotor apraxia is a failure to know how to
perform a complex motor movement — for instance,
patients might have trouble waving goodbye.
■ Ideomotor apraxia localizes to the left inferior
parietal lobule.
■ Balint syndrome (optic ataxia, gaze apraxia,
simultagnosia) is due to bilateral occipitoparietal
lesions.
■ Gerstmann syndrome is a four-part syndrome of
left –right disorientation, fi nger agnosia, dyscalculia,
and dysgraphia.
■ Gerstmann syndrome localizes to the left hemispheric
inferior parietal lobule with specifi c involvement of
the angular g yrus.
■ Hemispatial neglect involves a lack of regard for
objects in the contralateral hemisphere.
■ Right parietal lobe injuries can cause anosognosia,
which is a lack of awareness of the presence of a
defi cit.