Varieties of deficit unawareness after brain injury

The failure to recognize the existence of disease is known as anosognosia, This article provides a brief discussion of the evolution of this concept a nd reviews some qualitative differences in the manner in which the disavowa l of neurogenic impairment is expressed. Theoretical explanations for the u nawareness of deficit after neurologic illness include motivational-symboli c, cognitive subsystem, and supraordinate system theories. Observations fro m a clinically derived, structured awareness interview are presented, sugge sting three factors that may underlie patients' apparent lack of awareness of deficits after traumatic brain injury. These include diminished awarenes s of deficits secondary to impaired cognition, especially memory and reason ing deficits; psychological reactance and denial of deficits; and a relativ ely 'pure" inability to recognize areas of impaired functioning as a direct consequence of brain injury. The causes of unawareness are likely to be co mplex and multiply determined in any given patient, although it may be poss ible to identify primary, secondary, and even tertiary contributions accord ing to specific behavioral and phenomenological characteristics. The abilit y of patients to modify their perceptions and acknowledgment of deficits af ter objective feedback may have particular diagnostic value and clinical ut ility in this regard.