False recognition in Lewy-body disease and frontotemporal dementia.

The primary goal of this study was to evaluate the false recognition phenomenon in persons with frontotemporal dementia (FTD) and those with Lewy-body disease (LBD). Patients with LBD (n=10) or FTD (n=15) and their corresponding controls (n=30) were subjected to the Deese-Roediger-McDermott (DRM) paradigm to induce false recognition. Patients were first presented with items semantically related to a nonpresented critical target. The critical target was later included in a word list shown to patients to assess level of recognition. Both groups of patients showed a reduced level of false recognition of the critical target when controlling for their overall level of false alarms. This reduction was greater in persons with LBD than in those with FTD. Correlational analyses of performance on neuropsychological tests and the DRM variables indicated that the reduced DRM effect was associated with inhibition deficits in patients with LBD and with inhibition deficits and verbal memory in those with FTD. Our results support current models suggesting that these cognitive components contribute to the false recognition effect.