Why do some people experience clarity of mind before death?

A recent study describes and explains the phenomenon
Dr Michael Nahm, of the International Association for Near-Death studies, defines the phenomenon, as:
“The (re)emergence of normal or unusually enhanced mental abilities in dull, unconscious, or mentally ill patients shortly before death, including marked elevation of mood and spiritual affections, or the ability to speak in a previously unusual manner , spiritualized and euphoric”.
Research shows that not only do terminally ill patients exhibit this mental clarity in an apparent state of recovery, but also those suffering from mental illness become asymptomatic shortly before death. Terminal lucidity also sees patients who have lived with dementia for years return to their previous cognitive functions, only to die some time later.
The temporal gap between terminal lucidity and the moment of death has sparked a debate about the exact nomenclature to give to the phenomenon; in fact, further research has dubbed it “ paradoxical lucidity ,” due to the fact that the state of mental clarity can manifest itself hours, days, weeks, or even months before death.
Historical cases of terminal lucidity have been explained as consequences of changes in brain physiology brought about by death, even though there is a lack of detailed explanations and scientific evidence to support the phenomenon.
However, this is a particularly puzzling phenomenon to resolve because, in most cases, it occurs in patients whose brain function is considered irreversibly damaged by a disease, as in the case of Alzheimer’s. The question that arises is, therefore, how is it possible that apparently deleted memories are accessible again?
The answer is not yet certain, but given that it is a documented phenomenon that occurs often, the scientific community has decided to investigate in depth.
- Terminal lucidity in people with mental illness and other mental disabilities: an overview and implications for possible explanatory models. (Journal of near-death studies)