Aprosexia, hyperprosexia, and paraprosexia are closely related medical and neuro-psychiatric phenomena associated with attention and concentration. They typically occur in patients suffering traumatic brain injuries.
Aprosexia is an abnormal inability to pay attention, characterized by a near-complete indifference to everything.
Hyperprosexia is the abnormal state in which a person concentrates on one thing to the exclusion of everything else.[unreliable source?]
Paraprosexia is the inability to pay attention to any one thing (a state of constant distraction).
Patients suffering traumatic brain injury experience profound disturbance of the basic functions of the cognitive, behavioral, emotional and intellectual systems. Such patients' ability to regulate interaction between the ego and the external world is greatly diminished and they typically exhibit inflexible, concrete and sometimes inappropriate behaviors.