6 Special reportDementia The EconomistAugust 29th 2020
2 face tremendous pressure to cover it. But the drug will be extreme-
ly expensive, at least in its first, patent-protected years. Others ar-
gue that, since insurers will approve a treatment only for patients
for whom it is effective, the problem may not be so acute.
The best progress in treating the condition is likely to come
from combinations of drugs that deal with different aspects of the
brain. Dr Kivipelto, the Finnish neurologist, believes in the “cock-
tail” approach of combining drugs and behavioural therapies that
tackle different aspects of dementia’s pathology. That includes po-
tential genome editing, using crisprtechnology.
By the time people are diagnosed with dementia, it is usually
quite advanced. So another thrust of the scientific campaign is to
find ways of catching the condition earlier. Several techniques are
employed, besides cognitive testing. One is to identify those with a
genetic predisposition to Alzheimer’s. Three genes have been im-
plicated in the rare, inherited, early-onset form of Alzheimer’s. For
the more common sort, several genes have been found to increase
the risk, particularly one form of the apoegene, apoe4, which also
appears to raise the risk of heart disease and covid-19. This can be
detected by a blood test.
However, all it indicates is a somewhat higher risk, not the
presence of the disease. For this two other sorts of “biomarker” are
used. One is to measure levels of amyloid and tau in a person’s ce-
rebrospinal fluid. This requires a lumbar puncture (the insertion
of a needle into the lower spine). The other is a scan, usually a mag-
netic-resonance imaging (mri) scan, to look at the size of the
brain, along with a positron-emission tomography (pet) scan that
can measure the build-up of amyloid.
Scanners are expensive and often unavailable. So the search is
on for a simpler and cheaper approach. Many believe a blood test
offers the best prospects. At the Alzheimer’s Association’s annual
conference in July, hopes were raised by a test that could distin-
guish between Alzheimer’s and other
neurodegenerative conditions, and spot
those at risk years before symptoms ap-
pear. This measures a form of tau called p-
tau217, and was found to predict Alz-
heimer’s with 96% accuracy. It is already
possible, using the technique of mass spec-
trometry, to measure the level of beta-amy-
loid in the blood. But it is not known how
this relates to levels in the brain. A trial in
America last year found that the testmatched the result of a petscan 88% of the time, a hopeful result
but not accurate enough for a clinical diagnostic test. The success
rate rises to 94% if two other risk factors are considered: age and
the presence of the apoe4 gene.
Others look to the use of data and artificial intelligence (ai). Ku-
rokawa Kiyoshi, a professor of medicine at the Graduate Institute
for Policy Studies in Tokyo, argues that “data tech is progressing
much faster than biotech”. Data research should allow more exten-
sive mapping of correlations between physical conditions and be-
haviour and the later onset of dementia. Even without ai, scien-
tists can detect evidence of dementia from how people use words.
In her final novel, Iris Murdoch, who went on to develop severe
Alzheimer’s, uses a more limited vocabulary and simpler language
than in earlier works. Doctors analysing Ronald Reagan’s public
pronouncements say signs of Alzheimer’s could be detected in his
speech patterns years before his diagnosis in 1994.
Nowadays, the way people use digital technology—navigation
apps, for example, since impaired spatial awareness and sense of
direction are often early signs of dementia—may provide an early
indication of cognitive decline. This raises the uncomfortable
spectre of tech giants tracking their customers’ mental decay.
Those worried will be only partly reassured by studies showing
that the use of digital technology helps slow the process.
Even in the absence of data from apps, many factors have been
linked to an increased or reduced risk of dementia. A study pre-
sented at the July Alzheimer’s Association conference estimated
that dementia could be prevented or delayed in 40% of cases by
attacking 12 risk factors. It added three (excessive drinking or in-
curring head injuries in middle life, and exposure to air pollution
in old age) to nine already identified (including smoking, high
blood pressure, obesity, hearing loss, less education and diabetes).Hearts and minds
“What is good for the heart is good for the brain” is a bromide often
trotted out. So public-health campaigns intended to reduce the
chances of developing heart disease, cancer and diabetes will also
reduce dementia rates. Such is the fear of the disease that this
should reinforce efforts to promote healthy ways of life. What else
works against dementia is not certain, but it includes retaining so-
cial contacts and keeping an active mind (though learning some-
thing new such as a language is more effective than doing a famil-
iar puzzle like a crossword every day).
Dr Kivipelto’s study in Finland (known as the “finger” trial),
published in 2015, showed that changing ways of life could signifi-
cantly reduce the rate of mental decline. Conducted among a group
of 60- to 77-year olds with higher risk factors for dementia, it mon-
itored and changed lifestyles and put them through “cognitive
training”—computer-based mental gymnastics. She speculates
that for some, part of the benefit may have come from learning to
use computers and the internet for the first time.
There is evidence that the age-specific incidence of dementia is
going down as lifestyles change, notably in Europe—and going up
in others, such as China and Japan. A study published in the jour-
nal Neurologyearlier this month followed nearly 50,000 people in
America and Europe (clinically representative of no more than 16%
of the world’s population) from 1988 to 2015. It found that 8.6% de-
veloped dementia. But the risk of being among them had, remark-
ably, fallen by an average of about 13% a decade, from about a one in
four chance for a 75-year-old in 1995 to less than one in five now.
Yet however wholesome a person’s way of life and however
much they stretch their minds by learning Tibetan or reading The
Economist, they cannot eliminate the risk of dementia. For the
foreseeable future, there is no cure and the world will keep grow-
ing older. So how to look after people with dementia, and how to
pay for it, will be ever more pressing questions. 7Dementia could
be prevented
or delayed in
40% of cases by
attacking 12 risk
factors