Specific localizations have been hypothesized for localization objects, body parts, and colors. Fluent aphasias generally reflect Wernicke's area pathology, non-fluent aphasias reflect expressive difficulties in the frontal lobe Broca's area. Ask the person to construct a clock, e.g. with the time 10 past 11. This involves both sides of the visual field, and the 10 has to be conceived as a 2 on the clock. Tests of copying and construction while often cited as tests of praxis involve visuospatial perception and visuomotor integration - gnosis.
Substantial skill is required to differentiate the site of the lesion.
Tests such as middle finger of right hand involve testing of finger parts and testing of right and left orientation. This apparently simple task also involves touching the nose and then the ear and this requires sequential organization. These tasks therefore require additive evaluation in order to adequately interpret them. These functions therefore involve the perceptual, integrative, and executive functions. At the perceptual level, the patient would be agnosic, and this would predominantly reflect posterior parietal pathology.