False memories in Lewy-body disease

Recently, de Boysson, Belleville, Phillips etal. (2011) found that patients with Lewy-body disease (LBD) showed significantly lower rates of false memories than healthy controls, using the Deese-Roediger-McDermott (DRM) experimental procedure. Given that this result could be explained by the practically null rate of true recognition in the LBD group (0.09), we decided to replicate the study by de Boysson etal. (2011), but including a new condition that would maximize the true recognition rate (and analyze its effect on the rate of false memories). Specifically, in a DRM experiment, we manipulated (within subjects) two study and recognition conditions: in the immediate condition, both the LBD patients and the control group of healthy older people received a different recognition test after each study list (containing twelve words associated with a non-presented critical word), while in the delayed condition (similar to the one in de Boysson etal., 2011), the participants received the entire series of study lists and then took only one recognition test. The results showed that, in both samples, the immediate condition produced higher corrected rates of both true and false recognition than the delayed condition, although they were both lower in the LBD patients, which shows that these patients are capable of encoding and recognizing the general similitude underlying information (gist memory) in the right conditions.