Prevalence and Patterns of Unexpected Lucidity Among Deeply Forgetful Patients: Findings From a U.S. Population-Based Study.

ObjectiveReports from caregivers and other witnesses describe episodes of unexpected or paradoxical lucidity among adults diagnosed with dementia. However, until now, there has not been a representative national survey documenting its prevalence in the U.S. adult population. This study reports on (a) the prevalence of terminal or unexpected lucidity in adults diagnosed with Alzheimer's disease or other dementias, and (b) its distribution across sociodemographic characteristics and parameters of clinical cases.MethodData are from a nationally representative population-based survey of observers (N = 5940) of dementia patients, aged 40+, who experienced one or more episodes of unexpected lucidity.ResultsThe national prevalence of unexpected lucidity, according to observers, is 43.6% (weighted n = 2587). Episodes occur regardless of the age or sex of patients, parameters of the clinical case, or characteristics of observers.ConclusionFindings reveal that lucid episodes are not rare, but possibly a normative feature of the dementing process. If so, this has implications for clinical practice and ethical decision-making involving "deeply forgetful people."