Recovery from spontaneous confabulations parallels recovery of temporal confusion in memory

Background: In previous studies, the authors found that patients with spont aneous confabulation differ from those with nonconfabulating amnesia by 1) temporal context confusion (TCC) in memory based on an inability to suppres s intrusions of currently irrelevant memory traces into ongoing thinking; a nd 2) lesions involving the orbitofrontal cortex, basal forebrain, or amygd ala and perirhinal cortex. Objectives: To study the long-term clinical cour se of spontaneous confabulations, determine whether TCC in memory also para llels the clinical course of spontaneous confabulations, and study the impa ct of lesion site on clinical course. Methods: Eight patients with spontane ous confabulation were re-examined 18 months after onset. Tests of memory a nd executive functioning and measurement of TCC in memory were again applie d. MRI according to a standard protocol was performed to determine areas of permanent damage. Results: Seven patients eventually stopped confabulating . TCC, but not common memory or executive tests, precisely paralleled the c ourse of spontaneous confabulations. Patients with isolated, less extensive , orbitofrontal lesions stopped confabulating first and had the best neurop sychological outcome. Patients with basal forebrain lesions continued to co nfabulate for several months and remained amnesic. One patient with extensi ve orbitofrontal damage and perirhinal cortex damage continues to confabula te after more than 3 years, continuing to confuse memory traces. Conclusion s: Temporal context confusion in memory is not only the sole feature reliab ly separating patients with spontaneous confabulation from those with nonco nfabulating amnesia in the acute stage, it is also the only feature that pr ecisely parallels the clinical course of spontaneous confabulations. Most p atients eventually stop confabulating but duration of confabulations depend s on the lesion site.