Agnosia is loss of ability to comprehend the meaning of sensory stimulation, such as auditory, visual, olfactory, tactile, and gustatory sensations.
auditory a. Inability to recognize different sounds; usually due to a lesion in the auditory cortex of the temporal lobe of the brain.
tactile a. Failure to recognize objects or to appreciate their form by touch; caused by a lesion in the contralateral parietal lobe of the brain.
visual a. Inability to recognize objects by sight; usually due to a lesion in the visual association areas of the brain.