Agnosia

Agnosia (from ancient Greek ἀγνωσία, "ignorance", "absence of knowledge") is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. It is usually associated with brain injury or neurological illness, particularly after damage to the occipitotemporal border, which is part of the ventral stream. Agnosia only affects a single modality for example vision or hearing may be affected.