Lucid episodes in dementia patients mean they are not lost forever

Researchers have found dementia patients who had been assumed to have lost the capacity for coherent interactions experience lucid episodes
Researchers have found dementia patients who had been assumed to have lost the capacity for coherent interactions experience lucid episodes - Jasper Chamber

Lucid episodes are common in people with dementia and prove that loved ones are not gone forever, scientists have found.

There have been anecdotal reports that people with Alzheimer’s disease or other forms of dementia will sometimes experience periods of clarity, when they can recognise loved ones and regain memories, even if only temporarily.

Such episodes were often thought to be a harbinger of death, but the first major study of lucid episodes by the Mayo Clinic has found that half happen at least six months before death and show that the disease can be reversed.

Researchers surveyed hundreds of carers who had looked after dementia patients and found 61 per cent had witnessed a lucid episode, with nearly a quarter lasting longer than 30 minutes.

The team found most occurred after visits from family or friends, when they listened to music or when they reminisced about the past.

“We know these lucid episodes are happening, but we didn’t know if there are different types of episodes that happen at different times or under different circumstances,” said Dr Joan Griffin, the lead author of the study.

“It’s important for people to know that these are not necessarily harbingers for death. I think people can get anxious when they happen, so it’s good to know that there are different kinds of episodes that don’t necessarily mean death is imminent.”

Researchers defined lucid episodes as unexpected, spontaneous, meaningful and relevant communication from a person who is assumed to have permanently lost the capacity for coherent interactions.

The findings showed that 75 per cent of people having lucid episodes were reported to have Alzheimer’s, as opposed to other forms of dementia, and 61 per cent were women.

Unexpected presence

They were most often reported by children who did not live with the parent with dementia, and visited infrequently, suggesting that their unexpected presence might trigger the improvement.


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Around 12 per cent of cases did occur shortly before death, a phenomenon known as “terminal paradoxical lucidity” in which people regain memories and the ability to communicate in the days before they die.

The term was coined by Michael Nahm, the German biologist, after reading multiple cases in 18th- and 19th-century medical case reports.

Experts believe that the moments of clarity show that dementia can be reversed and that the memories and recognition are not lost forever. But they do not know how the brain restores the lost function during these moments of clarity.

The team are keen to discover if the episodes can be extended.

Writing in the journal Alzheimer’s & Dementia, the researchers concluded: “Findings suggest that multiple types of lucid periods exist, that not all are indicative of the end of life, and that some episodes are precipitated by external stimuli while others are not.

“Our findings challenge the clinical assumption of a linear cognitive and behavioural decline for people living with dementia, suggesting that this decline can, at least temporarily, shift.

“A deeper understanding of temporary reversals of cognitive ability could lead to pathways to induce some types of lucid episodes and extend the duration of others.”