[Delirium superimposed on dementia. Clinical practice and perspectives].

Delirium is a commonly encountered syndrome in clinical practice. Older people with cognitive disorders are most at risk of developing delirium during the hospital stay. However, the risk of underdiagnosis is significant, particularly because of the overlap of behavioral symptoms and cognitive impairment between delirium and dementia. With an aging population and an ever-increasing prevalence of cognitive disorders, this article exposes the bilateral relationship maintained between dementia and delirium and bring certain diagnostic tools and clinical management clues to support the clinician. Finally, the perspectives of ongoing clinical research that could respond to current challenges are discussed.