An interdisciplinary research team is investigating cases of paradoxical lucidity, a phenomenon in which a person with severe dementia suddenly “wakes up” and exhibits surprisingly normal behaviors, only to pass away shortly thereafter.
Writing in the journal Alzheimer’s & Dementia, the researchers outline what is known and unknown about paradoxical lucidity, consider its potential mechanisms, and detail how a thorough scientific analysis could help shed light on the pathophysiology of dementia.
The study is one of the first to scientifically investigate these phenomena, although these incidents have been reported all throughout history.
“Science is now trying to be thoughtful and attentive to something that has long been reported,” said study leader George A. Mashour, M.D., Ph.D., professor in the department of anesthesiology at Michigan Medicine and director of the Center for Consciousness Science.
“We’ve assumed that advanced dementia is an irreversible neurodegenerative process with irreversible functional limitations. But if the brain is able to access some sort of functional network configuration during paradoxical lucidity, even in severe dementia, this suggests a reversible component of the disease.”
The new paper describes earlier work documenting case studies of individuals with advanced dementia, including Alzheimer’s disease, appearing to be able to communicate and recall in a seemingly normal fashion at the end of life, to the astonishment of their caregivers.
“The accumulation of anecdotal reports about paradoxical lucidity in the scientific literature prompts several important research questions,” said National Institute on Aging (NIA) medical officer Basil Eldadah, M.D., Ph.D.
“We look forward to additional research in this area, such as better characterization of lucidity in its varying presentations, new instruments or methods to assess episodes of lucidity retrospectively or in real-time, tools to analyze speech patterns or other behavioral manifestations of lucidity, and evidence to inform decision-making challenges and opportunities prompted by unexpected lucidity.”
One precedent for studying such events exists in the research of near-death experiences. In 2013, Mashour and his team at Michigan Medicine published a study showing evidence of electrical brain features indicative of a conscious state following cardiac arrest.
“We don’t know that the same thing is occurring with paradoxical lucidity, but the fact that this is usually happening around the time of death suggests there could be some common neural network mechanism,” he says.
Mashour acknowledges that researching paradoxical lucidity will be a challenge, given the fleeting nature of the phenomenon. Case studies report episodes lasting from mere seconds to at most several days in a small minority of cases.
The research team also outlines important ethical implications of this work, including the ability of vulnerable patients to participate in research and how the observation of paradoxical lucidity might change the way caregivers interact with people with dementia.
“Would research that might identify a systematically observable paradoxical lucidity provide comfort, for example, by offering loved ones a potential channel for closure, or might it induce worry if loved ones are left to wonder if a reversible cause of the dementia could have been found? We do not know the answers but these could be important research questions in their own right,” said co-first author Lori Frank, Ph.D., of the RAND Corporation and former Health and Aging Congressional fellow with the National Institute on Aging.
The research team, assembled by the National Institutes of Health’s (NIH) National Institute on Aging, hopes their paper will help raise awareness within the scientific community to help make further progress in paradoxical lucidity research, as well as validate the experiences of a multitude of caregivers.