Visual
Agnosia is a rare neurological disorder that leaves the individual unable to recognize faces, objects, , or places. It is a result of lesions on the brian and depending on the area of the damage it can affect different sensations. Below are the three major classes of agnosia, auditory, visual, or tactile.
Three Basic Types
ABOUT
Caused by damage to Wernike's area of the brain in the parietal lobe, auditory agnosia is the inabilitiy to recognize sounds, words, or music. Auditory agnosia can be in the form of pure word agnosia, the inability to repeat or understand spoken language, or auditory agnosia for sounds dealing with the environment.
Auditory
Due to lesions in the parietal lobe, tactile agnosia is the inability to recognize objects by touch. Tactile agnosia can even be limited to one area, such as a case of a 61-year-old man, who after a stroke, was unable to idenify objects by touching them with his left hand, but when using his right he still had the abilty to recognize the different objects.
Tactile
The inability to recongnize faces, objects, places or sounds that use to be framiliar. There are two subdivisions of visual agnosia; primary and secondary. Primary visual agnosia from a an injury to the brain and secondary agnosia is from a disease, such as alzhimers, the effects the brain and leads to agnosia as a secondary diagnosia to the first disorder. Visual agnosia can consists of two different types; apperceptive or associative visual agnosia.
Impact on the Brain
Agnosia is caused from a lesion on the brain, specifically the temproal, occipital or parietal lobe. The damage can stem from trauma, strokes, diseases, such asalzheimers, or chemicals, such as carbon monozixde. Visual agnosia is from damage to the occiptal lobe, which processes visual information. The auditory cortex is located within temporal lobe and when damage occurs there it can lead to auditory agnosia. Tactile agnosia is caused from damage to the parietal lobe which processes sensory information.