Several case reports in the 19th century described the unusual condition of an improvement and recovery of the mental state in people days or weeks before death.
[11][12] In 2018, a group of researchers at Dongguk University Ilsan Hospital published a study involving the observation of people weeks prior to death.
[13] A survey of 45 Canadian palliative care volunteers reported that 33% of them personally witnessed at least one case of terminal lucidity within the past year.
[20] Research in 2020 screened for "paradoxical lucidity", a general term for unexpected remissions in dementias, independent of whether the person died shortly thereafter.
The research found that in only 6% of the paradoxical lucidity cases did the person live longer than a week, and stated that it is a "primarily death-related phenomenon".
But as new research emerges and more insight is gained on previously poorly understood mechanisms involving the brain, it may be discovered that what was initially assumed to be permanent is actually reversible.
Near-death experiences have been reported worldwide, independent of culture, by people who unexpectedly recovered from life-threatening injury or by individuals who escaped a potentially fatal situation.
Case reports have found that there is a sudden increase in brain electrical activity that is normally associated with consciousness in people who are dying due to critical illness.
[8] The earliest attempt at explanation was issued by Benjamin Rush in 1812, which hypothesized that a reawakening could be due to a nervous excitation caused by pain or fever, or because of dead blood vessels, released by a leakage of water in the brain chambers.
[17][31] In 2018, the US National Institute on Aging (NIA) announced two funding opportunities in order to encourage scientists to advance nascent science of lucidity.
[33] In 2021, a non-tested hypothesis of neuromodulation was proposed, whereby near-death discharges of neurotransmitters and corticotropin-releasing peptides act upon preserved circuits of the medial prefrontal cortex and hippocampus, promoting memory retrieval and mental clarity.
[34] A study by NYU Langone Health in collaboration with the NIA which began in 2022 and is set to end in 2025 "aims to establish methods for measuring episodes of lucidity" in people with severe end-stage dementia.
[35] The Penn Program on Precision Medicine for the Brain (P3MB) have several current projects in the works in partnership with various organizations such as the Alzheimer's Association, the CDC, and the NIA.
[36] Undertaking a multidisciplinary approach, P3MB conducts and participates in various research involving neurological diseases with the aim to potentially translate new discoveries into clinical practice.
This process is being explored as a potential treatment for Alzheimer's disease, though as of 2024 further research is still required to ensure safety and determine long-term effects.
Deep sedation, which is often used to alleviate intractable symptoms, could deprive patients of the opportunity to experience moments of clarity and connection with loved ones before dying.
[19] Terminal lucidity may provide a positive experience for family members who see these moments of clarity as a way to resolve unfinished business, reach closure, or reaffirm spiritual beliefs.