Scientists decode why memories come back to dementia patients before death

Dementia has become rampant among human beings who are pushed into a deep mental abyss, devoid of memories and remembrance.

It has been termed as "the long goodbye". Even though the person remains alive, memories fade away slowly and irreversibly due to dementia.

Dementia eventually snatches away the ability of a person to communicate, eat and drink on their own, recognise family members and understand where they are.

From the 19th century, caregivers and health-care workers have described people suffering from dementia as becoming lucid.

The healthcare workers said that such people were engaging in meaningful conversations, making jokes, sharing memories which were assumed to have been lost, and even asking for meals.

According to the study, an estimated 43 per cent of people go through brief lucidity and then die within 24 hours, and 84 per cent die within a week.

Here's why this occurs?

The term "terminal lucidity" was coined by researchers Michael Nahm and Bruce Greyson in 2009 since it was registered that such lucid episodes often occurred just before death.

However, studies suggest that not all such lucid episodes indicate that death is imminent. As per one study, many people suffering from advanced dementia have shown brief memories of their own selves more than six months before dying.

There have also been reports of cases of lucidity in other conditions such as meningitis and schizophrenia - which affect the thinking skills or the brain - and in people who have brain tumours or have sustained a brain injury.

The moments of lucidity which do not necessarily indicate death are sometimes called paradoxical lucidity. They are considered as paradoxical as it goes against the expected course of neurodegenerative diseases like dementia.

However, such episodes of lucidity are temporary and do not hint at any reversal of neurodegenerative disease.

Scientists struggle to find cause of terminal lucidity

Scientists have been struggling to explain why terminal lucidity occurs. Few episodes of lucidity were noted to have occurred when the patient's loved ones were around him or her.

Some studies have also hinted at music improving lucidity.

Watch: London's 'light into life' exhibition inspired by nature and science However many episodes of lucidity do not have a distinct trigger. New York University's research team has speculated that changes in brain activity before death may lead to terminal lucidity.

However, this fails to explain why people suddenly recover from their abilities that they had once forgotten. It is also very difficult to explain paradoxical and terminal lucidity.

Not all those with advanced dementia experience episodes of lucidity just before death.

(With inputs from agencies)