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.
Associative visual agnosia
The affected individual may not realize that they have a visual problem and may complain of becoming "clumsy" or "muddled" when performing familiar tasks such as setting the table or simple DIY.
Anosognosia, a lack of awareness of the deficit, is common and can cause therapeutic resistance. In some agnosias, such as prosopagnosia, awareness of the deficit is often present; however shame and embarrassment regarding the symptoms can be a barrier in admission of a deficiency. Because agnosias result from brain lesions, no direct treatment for them currently exists, and intervention is aimed at utilization of coping strategies by patients and those around them. Sensory compensation can also develop after one modality is impaired in agnostics