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.
Cognitive disorder
Although Alzheimer's disease accounts for the majority of cases of neurocognitive disorders, there are various medical conditions that affect mental functions such as memory, thinking, and the ability to reason, including frontotemporal degeneration, Huntington’s disease, Lewy body disease, traumatic brain injury (TBI), Parkinson’s disease, prion disease, and dementia/neurocognitive issues due to HIV infection.
Neurocognitive disorders are diagnosed as mild and major based on the severity of their symptoms. While anxiety disorders, mood disorders, and psychotic disorders can also have an effect on cognitive and memory functions, the DSM-IV-TR does not consider these cognitive disorders, because loss of cognitive function is not the primary (causal) symptom. Additionally, developmental disorders such as Autism spectrum disorder are typically developed at birth or early in life as opposed to the acquired nature of neurocognitive disorders.