<unk> , or the lack of<unk>  ability, results from brain damage, particularly to the parietal lobe, thalamus, and secondary somatosensory cortex. A significant relationship has been found between<unk>  and people living with Alzheimer's disease. Alzheimer's patients typically experience the lack of sensation in both their dominant and non-dominant hands. Astereognosis, the inability to identify a physical object solely by touch, is commonly found in conjunction with<unk>  in Alzheimer's patients. Some research suggest that<unk>  can be used to track the cognitive decline in Alzheimer's patients once the disease is diagnosed. Studies also show that patients diagnosed with schizophrenia and their immediate relatives have a decreased ability to perform<unk>  tasks in comparison to people without relatives diagnosed with schizophrenia. Therefore, researchers have suggested that somatosensory dysfunction in the parietal cortex is a potential cause of<unk>  impairments.
Agraphesthesia
Dysmorphopsia
Palinopsia
Metamorphopsia
Homonymous hemianopsia
Pelopsia
Cynanthropy
Akinetopsia