Agnosia

Agnosia is a higher cortical dysfunction in which a patient is unable to recognize objects, persons, sounds, shapes, or smells despite intact primary sensory function. It results from focal lesions in the occipital, parietal, or temporal lobes, often due to stroke, traumatic brain injury, or neurodegenerative disorders. Clinical subtypes include visual, auditory, tactile, and prosopagnosia. Diagnosis involves detailed neuropsychological assessment and neuroimaging to localize the lesion. Treatment is primarily supportive and rehabilitative, aiming to improve compensatory strategies, although prognosis depends on lesion extent and neuroplasticity.