[Memory deficits and confabulation].

The term "confabulation" refers to a verbal statement of fabricated, distorted or misinterpreted memories about oneself or the world, without the conscious intention to deceive. The difference between confabulation and delusion lies in the fact that the former is essentially linked with memory deficits and the latter is characterized by a firm belief in false stories. It has been established that delusion often arises from personality or emotional problems; however, the premorbid personality of confabulators has not been clarified. Confabulation is usually divided into 2 types-provoked and spontaneous. Theoretical explanations for the cognitive mechanisms underlying confabulation includes the notion that confabulation reflects the tendency of filling gaps in memory. It has also been suggested that confabulation is the consequence of memory loss and frontal dysfunction, specifically dificits in self-monitoring and/or reality monitoring. A number of studies have indicated that temporal context confusion in memory is a characteristic trait of confabulators. Recently, it has been suggested that spontaneous confabulators fail to suppress previously activated memory traces or currently irrelevant memory traces, which intrude into ongoing thinking. In addition, it has been indicated that confabulation can be attributed to problems in the regulation of autobiographical recollection. This account may explain why confabulators focus on particular themes and why the content of confabulations is distorted toward more positive and optimistic self-representations. Lesions involving the basal forebrain and the orbitofrontal cortex may lead to confabulation. In particular, patients with severe or chronic spontaneous confabulation appear to have multiple lesions involving the basal forebrain and the orbitofrontal cortex, including the striatum or the dorsolateral prefrontal cortex. Cognitive rehabilitation methods such as keeping a diary, re-orientation, and self-monitoring training are reported to reduce the severity of confabulation.