Category: Dementia

A steady decline? Experts question whether the human brain really slows down with age.

Linguistic experts argue that people’s brains do not slow down with age, but actually show the benefits of experience.

Tests that had previously been taken to show cognitive decline as people age, they maintain, are actually showing the effects of having more information to process.

While accepting that physiological diseases of old age clearly exist, they say that the usual cognitive changes associated with age are exactly what you’d expect as the brain gathers more experience.

Remembering names

As linguists, they decided to test their theory using words–specifically the number of words that a person learns across their lifetime.

They set up a computer simulation to model this.

As the simulation got ‘older’, it began to slow down as it learnt more words–exactly as people do with ageing.

The lead author of the study, Dr Michael Ramscar, explained it like this:

“Imagine someone who knows two people’s birthdays and can recall them almost perfectly.

Would you really want to say that person has a better memory than a person who knows the birthdays of 2000 people, but can ‘only’ match the right person to the right birthday nine times out of ten?”

It’s not that people are forgetting words with age, it’s that there are more words competing for attention.

People face a similar problem with names: as they age, they learn more names, so one name is harder to recall because it is competing with a larger pool of alternate names in memory.

On top of this, names have become varied.

The authors give the example that in the 1880s, when trying to recall a woman’s first-name, there were about 100 equally possible alternatives.

Due to the greater variety in first-names now, however, you’d be trying to choose between 2,000 likely alternatives.

Age and experience

Even better news for the ageing population, the linguists argue, is that older people are actually making better use of the extra information that comes with experience.

On some tests, related to learning pairs of works, older people do better as they have access to more words which have been learnt over a lifetime.

Biology

What, you might wonder, about all the neurobiological evidence that the brain’s cognitive powers decline with age?

Well, excepting real diseases like Alzheimer’s, scientists have only discovered that the brain changes with age, not that these changes are the cause of any cognitive decline.

It has only been assumed that neurobiological changes in the brain are related to cognitive declines, since these two were thought to be happening simultaneously.

Now that there are questions over whether cognitive declines are really there, these neurobiological changes may have to be reassessed.

Is cognitive decline a myth?

If cognitive decline with age really is a myth then, the authors worry, simply being told that your brain slows down with age is damaging.

That’s because when people are told they are getting more stupid, they behave as though this were true.

The authors conclude by saying:

“…population aging is seen as a problem because of the fear that older adults will be a burden on society; what is more likely is that the myth of cognitive decline is leading to an absurd waste of human potential and human capital.

It thus seems likely that an informed understanding of the cognitive costs and benefits of aging will benefit all society, not just its older members.”

The study was published in the journal Topics in Cognitive Science (Ramscar et al., 2014).

Losing this sense is the strongest early sign of dementia.

Older people who cannot identify smells like lemons, paint-thinner and roses are at double the risk of developing dementia, research finds.

Problems with other senses, such as vision, hearing and touch, can also be indicative of dementia.

However, difficulty with smell is the biggest sensory sign of dementia.

Other early signs of dementia include changes in sense of humour, increased apathy, memory problems and being unaware of those memory problems, being unable to understand sarcasm and insomnia.

Dr Willa Brenowitz, the study’s first author, said:

“Sensory impairments could be due to underlying neurodegeneration or the same disease processes as those affecting cognition, such as stroke.

Alternatively, sensory impairments, particularly hearing and vision, may accelerate cognitive decline, either directly impacting cognition or indirectly by increasing social isolation, poor mobility and adverse mental health.”

The study included almost 1,800 people in their 70s who were tracked for up to 10 years.

Around one-in-five developed dementia during that time.

The results showed that people with poor senses were at twice the risk of developing the disease.

While previous research has focused on smell, this study added together the effects of all the senses.

Dr Brenowitz said:

“The olfactory bulb, which is critical for smell, is affected fairly early on in the course of the disease.

It’s thought that smell may be a preclinical indicator of dementia, while hearing and vision may have more of a role in promoting dementia.”

People’s whose sense of smell declined by 10 percent were at a 19 percent greater risk of dementia, the study found.

Declines in hearing touch and vision were linked to a 1-to-3 percent level of increased risk.

Dr Kristine Yaffe, study co-author, said:

“We found that with deteriorating multisensory functioning, the risk of cognitive decline increased in a dose-response manner.

Even mild or moderate sensory impairments across multiple domains were associated with an increased risk of dementia, indicating that people with poor multisensory function are a high-risk population that could be targeted prior to dementia onset for intervention.”

The study was published in the journal  Alzheimer’s and Dementia (Brenowitz et al., 2020).

Alzheimer’s is the most common form of dementia.

Drinking higher amounts of coffee can reduce the risk of Alzheimer’s, research suggests.

Coffee was linked to reduced levels of amyloid plaques in the brain — these are thought to be key to Alzheimer’s.

Alzheimer’s is the most common form of dementia.

People who drank coffee also had higher levels of cognitive function.

Another recent study found that drinking tea or coffee may reduce the risk of stroke and dementia by around one-third.

Dr Samantha Gardener, the study’s first author, explained:

“We found participants with no memory impairments and with higher coffee consumption at the start of the study had lower risk of transitioning to mild cognitive impairment—which often precedes Alzheimer’s disease—or developing Alzheimer’s disease over the course of the study.”

Drinking coffee could be an easy way to delay Alzheimer’s disease, Dr Gardener said:

“It’s a simple thing that people can change.

It could be particularly useful for people who are at risk of cognitive decline but haven’t developed any symptoms.

We might be able to develop some clear guidelines people can follow in middle age and hopefully it could then have a lasting effect.”

Increase to two cups

The study suggests that for a person drinking one cup of coffee a day, it may be worth increasing to two cups a day.

Dr Gardener said:

“If the average cup of coffee made at home is 240g, increasing to two cups a day could potentially lower cognitive decline by eight percent after 18 months.

It could also see a five percent decrease in amyloid accumulation in the brain over the same time period.”

However, the study wasn’t able to determine the maximum number of cups of coffee that is beneficial or whether caffeination or adding milk make any difference.

Dr Gardener said:

“We need to evaluate whether coffee intake could one day be recommended as a lifestyle factor aimed at delaying the onset of Alzheimer’s disease.”

The study was published in the journal Frontiers in Aging Neuroscience (Gardener et al., 2021).