Covert versus overt self-recognition in late stage Alzheimer's disease.

Some persons with Alzheimer's disease (AD) lose the ability to recognize themselves, as when they cannot overtly recognize their reflection in a mirror. There is evidence, however, that covert or unconscious self-recognition might be displayed in such individuals. In this study, 3 persons with AD lacking the ability to overtly self-recognize demonstrated multiple instances of unconscious or covert self-recognition. A variety of interventions, inspired by research with prosopagnosics, was implemented to remediate this loss. Interventions enabled all participants to exhibit overt self-recognition, though each did so with the aid of a different intervention. In addition, successful overt self-recognition required a verbal probe and was entirely intervention-dependent: When the intervention was removed, overt self-recognition was lost. Results support a dissociation between explicit-declarative versus implicit-nondeclarative memory systems, and extends this dissociation into the realm of self-recognition in AD.