Priming performance in Alzheimer's disease: The role of task sensitivity

Studies examining implicit memory performance in Alzheimer's disease (AD) h ave yielded inconsistent findings, with these patients demonstrating impair ed performance within some priming studies and intact performance within ot hers. The present study examined the role of task sensitivity in detecting impaired priming in memory-impaired patients. Twelve healthy older adults a nd 12 AD patients were administered a picture fragment identification test. Task sensitivity was increased by employing stimulus cues expected to prod uce larger and more variable priming effects than obtained in previous stud ies. A simple comparison of priming scores revealed that the AD patients de monstrated significantly impaired priming relative to normal control partic ipants. However, further analysis of priming in relation to certain stimulu s characteristics revealed that AD patients often demonstrated impaired pri ming when overall priming effects were large but relatively intact priming when priming effects were small. These findings suggest that the prevention of ceiling effects in control participants may aid in the detection of imp aired priming in patient populations.