Agnosia is a condition where you are unable to properly perceive objects.
It's the result of damage to the brain, usually in the occipital lobe (which is where the brain handles visual processing) or parietal lobes (where the brain processes peripheral sensory information). It affects how your brain is able to identify and perceive objects around you.
Agnosia may impact any of the senses, although it usually only affects a single sense. For example, a person suffering from auditory agnosia may not be able to identify a sneeze based on its sound, but would have no trouble visually identifying a person who is sneezing. A person suffering from visual agnosia may not be able to distinguish the spoon in a set of flatware but has no problem with sense of taste. If you suffer from gustatory agnosia, you may not be able to identify your favorite culinary dish. And so on. This type of damage may result from a tumor, injury or degeneration, and may be caused by stroke, dementia, brain lesions, and other neurological problems and developmental conditions.
While most people will recover from agnosia within three months, it may take as much as a full year for the condition to resolve.