Interference and Negative Priming in Normal Aging and in Mild Alzheimer's Disease

Most studies that have administered interference and negative priming tasks to patients with Alzheimer’s disease (AD) and healthy elderly subjects have demonstrated inhibitory dysfunction in AD patients, and mixed results in the elderly. In the present study, we re-explored these two effects in these populations by administering two tasks that allow assessing interference and negative priming effects. Results on both tasks showed (1) the presence of an interference effect in AD and elderly adults, that can be explained by cognitive slowing in the case of elderly controls; (2) the preservation of negative priming abilities in the two groups. These surprising results for AD patients were interpreted by proposing that AD patients have a preserved ability to suppress the representation of a distracter, but specific inhibitory deficits when they have to resolve a selection conflict at the stage of response production (i.e. when competing stimuli have been fully processed).