Confabulation and delusional denial: frontal lobe and lateralized influences.

Various forms of confabulation, including denial of illness (e.g., paralysis, blindness), and conditions that often give rise to these disorders, such as cerebral disconnection, disinhibitory states, incomplete information reception, and "gap filling" are discussed. On the basis of clinical observation and a review of a number of studies, it appears that confabulatory states frequently are associated with cerebral damage that involves the right hemisphere, notably, the frontal (often bilaterally) and parietal lobes--areas intimately involved in arousal, attention, information regulation, and integration. With certain forms of injury, initially there appear disturbances in the organization, integration, and assimilation of ideas and associations, such that large gaps appear in the information transmitted to and received by the language axis of the left hemisphere. It is argued that in these instances, the language areas act so as to fill these "gaps" with information that, although inappropriate, is linked in some manner to the fragments received. In contrast, frontal lobe damage sometimes results in gross disinhibition and cortical overresponsiveness and, thus, speech release due to the flooding of the language axis (and other cortical regions) with tangential, fantastical, and grandiose associations. Other forms of confabulation also are reviewed briefly.