is characterized by an inability to recognize and identify objects and/or persons. Symptoms may vary, according to the area of the brain that is affected. It can be limited to one sensory modality such as vision or hearing; for example, a person may have difficulty in recognizing an object as a cup or identifying a sound as a cough. Agnosia can result from strokes, traumatic brain injury, dementia, a tumor, developmental disorders, overexposure to environmental toxins (e.g., carbon monoxide poisoning), or other neurological conditions. Visual agnosia may also occur in association with other underlying disorders. People with agnosia may retain their cognitive abilities in other areas. Treatment of primary agnosia is symptomatic and supportive; when it is caused by an underlying disorder, treatment of the disorder may reduce symptoms and help prevent further brain damage. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.