The Lucidity That Returns Mid-Illness

“It was like a flickering light bulb: never knew when or how long, but it always brightened the room.” A 72-year-old man wrote that about a friend with dementia, in a survey he filled in during April 2023.

Clinicians and researchers have several names for these moments: terminal lucidity, paradoxical lucidity, episodes of lucidity. Someone who has not recognised their family for a long time, and can no longer hold a sentence together, calls a daughter by name, answers a question, remembers something. Minutes or hours later the clarity is gone again. The most widely cited definition, put forward in 2019 by a group connected to a US National Institute on Aging workshop, describes “unexpected, spontaneous, meaningful, and relevant communication or connectedness” in a patient assumed to have permanently lost the capacity for coherent interaction.

For a long time the evidence came as single cases, many of them from deathbeds, which is where the term “terminal lucidity” comes from. A study published in May 2026 in the International Journal of Psychiatry in Medicine looks at the phenomenon from much further away. Jeff Levin, Rebecca Bonhag, Byron R. Johnson and Stephen G. Post analysed a Gallup survey of an online panel of US adults aged 40 and over, fielded from 7 to 10 April 2023. Of 12,448 people invited, 5,944 responded; 5,940 remained after data cleaning.

Who saw it

One screening question asked: “Have you ever witnessed an unexpected return of mental clarity in a family member, friend, or any individual with dementia?” After weighting, 43.6% said yes. That figure describes witnesses: the share of US adults over 40 who say they have seen it at least once, including in the denominator people who have never known anyone with dementia. How many patients have such episodes is a separate quantity, and the survey cannot supply it.

The 2,573 people who answered yes then described one person each, and those descriptions are where the study adds something new.

In the middle of the illness

In 80.7% of the cases described, the first observed episode came at what the witness called a moderate stage of dementia. Another 16.1% placed it at a severe or advanced stage, and only 3.2% at a terminal one. Before the most recent episode, just over half of the patients had moderate difficulties with memory and thinking, 35.8% had extreme difficulties, and almost one in ten was awake but unresponsive, or mostly unconscious.

It was seldom a single event. About a third of the patients (32.8%) had one or two observed episodes; nearly a quarter (23.7%) had nine or more. The episodes were short. Among witnesses who remembered how long the latest one lasted, 56.6% said fifteen minutes or less and 11% said over an hour, while more than a fifth could not recall its length at all.

In these reports, then, the phenomenon mostly sits inside a long illness, often one diagnosed more than ten years earlier (42.3% of cases), and it tends to recur. The final goodbye before death, the scene that gave it its name, is a small minority in the data.

What remains uncertain

Everything comes through the witnesses. No patient was examined, no episode was recorded as it happened, and the survey cannot show what each respondent counted as a “return of mental clarity”. A daughter and a nurse may apply different standards. The authors acknowledge this and write that whether they have over- or underestimated prevalence “is probably not determinable in these data”. The data belong to Gallup and are not available, and the study was not preregistered.

From these results the authors draw an interpretation: lucid episodes may be “a normative feature of the dementing process”, and upwards of half of patients might experience one. That is a hypothesis, reaching beyond what the sample measured. On mechanism, the paper lists proposals that range from a neurochemical cascade to gut microbiota to theories of consciousness, and explicitly declines to evaluate them.

There is a way past the limits of recollection, though it is slow: following patients over time under protocols fixed in advance, and recording episodes when they occur. The paper cites a few such studies, still at an early stage.

The people in the room

The same questionnaire also asked how those moments felt. In a 2024 paper in the Journal of Alzheimer’s Disease, Post and colleagues report on 2,111 witnesses. The emotion chosen most often was gratitude (58.7%), followed by feeling connected (53.4%); 14.1% said they felt stressed and 13% overwhelmed.

Among the free-text answers is one from a 65-year-old woman: “It was a shock to have him know me and directly/precisely express his love. He was back!” She cried all the way home, she wrote, knowing he would recede into his “tenebrific and confused stare”.

A 54-year-old man, writing about a relative: “Each time we would wonder if it was the last time.”