Science / Psychiatry / Agnosia: Failure to recognize or identify objects despite intact sensory function; This may be seen in dementia of various types. An example would be the failure of someone to recognize a paper clip placed in their hand while keeping their eyes closed.
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Science / Psychiatry / Spatial Agnosia: Inability to recognize spatial relations; disordered spatial orientation. MORE
Science / Psychiatry / Simultanagnosia: Inability to comprehend more than one element of a visual scene at the same time or to integrate the parts into a whole MORE
Science / Psychiatry / Prosopagnosia: Inability to recognize familiar faces that is not explained by defective visual acuity or reduced consciousness or alertness. MORE