Agnosia
Agnosia is the inability to process sensory information. Often there 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, such as vision or hearing. More recently, a top-down interruption is considered to cause the disturbance of handling perceptual information.
Cerebral atrophy
Many diseases that cause cerebral atrophy are associated with dementia, seizures, and a group of language disorders called the aphasias. Dementia is characterized by a progressive impairment of memory and intellectual function that is severe enough to interfere with social and work skills. Memory, orientation, abstraction, ability to learn, visual-spatial perception, and higher executive functions such as planning, organizing and sequencing may also be impaired. Seizures can take different forms, appearing as disorientation, strange repetitive movements, loss of consciousness, or convulsions. Aphasias are a group of disorders characterized by disturbances in speaking and understanding language. Receptive aphasia causes impaired comprehension. Expressive aphasia is reflected in odd choices of words, the use of partial phrases, disjointed clauses, and incomplete sentences.