Your questions on Alzheimer's answered by an expert

Dr Murali Doraiswamy, a physician at Duke University Health System and coauthor of The Alzheimer's Action Plan, responds to questions sent in from our Facebook audience.

Do we know what cause Alzheimer's? Are there are preventive measures we can take? (Question from Nidaa Darr)

Alzheimer’s is caused by progressive nerve cell death but we don’t yet fully know what causes this. Theories range from buildup of toxic brain proteins and plaques, inflammation, autoimmune damage, brain infections, loss of signaling chemicals and blockages in blood vessels. Scientists are hopeful that large ongoing brain research programs such as the Alzheimer’s Disease Neuroimaging Initiative, the China Brain Project and Genes to Therapies project will provide new answers. Ultimately we may need to double or triple our investment in brain research to accelerate the search for causes and cures.

There is no proven way to prevent Alzheimer's yet. A number of experimental treatments and vaccines are undergoing clinical trials. In a recent early phase study, immunotherapy, with a monoclonal antibody called aducanumab, cleared brain plaques and improved cognition – if the results hold up in larger trials that will be a breakthrough.

My top recommendations to keep your brain healthy are 1) Watch your body weight, blood pressure, cholesterol and sugar (through annual check-ups) so they are in normal range. 2) Exercise regularly. 3) Follow a heart healthy diet such as a Mediterranean diet or plant-based diet. 4) Minimize your risk of head injury by wearing helmets when appropriate. 5) Stay socially active. 6) Pursue mentally stimulating activities. A two-year trial recently showed these strategies could prevent cognitive decline in at-risk individuals.

Is this a genetic disease? (Begümhan Bilici Kurşunoğlu)

In people with early-age-onset, familial Alzheimer’s, which comprises about 2-3% of all cases, a genetic mutation is the cause. If a woman carries such a gene, she could potentially choose a new genetic technique called PGD (pre-implantation genetic diagnosis) to select embryos free of the Alzheimer’s gene to conceive a healthy baby. We recently reported using PGD to help a family with five generations of familial dementia break this cycle. Genetics is also thought to account for at least 50% of the more common form of late-age Alzheimer’s. The apolipoprotein E4 gene, carried by one in four Caucasians, can double or triple a carrier’s risk. The Alzheimer’s Prevention Initiative, the DIAN trial and the A4 trial are testing ways to delay the onset of Alzheimer’s in such at risk individuals.

Is there any genetic test to find out if you will develop Alzheimer’s and if it will be transmitted to your children? (Georgia Jo)

Yes there are genetic blood tests for rare familial forms of the disease that can be done at any dementia specialist’s office. Such tests should be followed with genetic counselling since the results can often be unsettling given there is no cure. I don’t recommended getting such testing done through online companies. There is no definitive predictive genetic test for the more common form of Alzheimer’s at present.

Do you think that there is a link between Alzheimer's and gut bacteria? (Samo Paulini)

Yes but it is not well studied yet. Several decades ago, the Nobel laureate Elie Metchnikoff postulated that "good gut bacteria" may delay senility. The gut microbiome (technical term for gut bacteria) can influence levels of many brain chemicals and there is essentially a two-way communication between the brain and gut. The Cure Alzheimer’s Fund is studying this and the Alzheimer’s Disease Metabolomics Consortium will soon publish important links. You can also read my recent blog on the growing links between brain infections and Alzheimer’s.

What kind of physical activity is best for preventing Alzheimer's? How much can music and other forms of art help? (Atul Deshpande)

Walking five times a week for 30-45 minutes a day is the best, in my opinion. A two-decade study of 387 women showed that even gentle regular physical activity (e.g. walking around the block on a daily basis) was associated with better memory 20 years later. One does not have to be a gym rat or run laps - in fact some studies show that vigorous running may shrink the brain. Two large studies, ENLIGHTEN and EXERT, are more conclusively testing whether exercise can improve cognition.

Specific brain networks are strengthened by playing music but we don’t yet know if this protects against dementia. We do know that people who speak two or more languages have a lower risk so it is possible this may hold true for music as well. A Swedish study is testing this. Music can help calm people with late stage dementia and bring back associated memories.

What is the probability for a person who has no family history of Alzheimer’s getting the disease? (Manimaran T)

Such a person’s lifetime risk is about 10-12%. Some studies suggest the risk may be higher in women than in men but this is not yet fully proven. If you have a family history then the risk can be raised 2-3 fold or even higher depending on the genes inherited.

Are there any signs we can notice at an early age which predict that someone will get Alzheimer's? (Bouba Koriem)

There is no perfect predictive test for dementia at an early age but many blood tests and brain scans are in development. One study of handwritten autobiographies of nuns in their 20s showed that low linguistic ability predicted dementia six decades later. Another study found that a vascular risk factor score (obesity, high blood pressure, high cholesterol) could predict dementia 20 years later in middle-aged people. Silent build-up of Alzheimer’s plaque pathology can be detected via new brain scans and in one study, people with a positive scan were more likely to deteriorate cognitively over the next three years than those with a negative scan. Ultimately, new home sensors that can analyze people’s speech patterns, TV watching patterns, or ability to handle appliances may make it possible for early signs of dementia to be detected passively simply by flagging deviations from norm.

What are the differences between Alzheimer's and dementia? (Anne Grey)

Dementia is an umbrella term used to refer to anyone whose cognitive and reasoning abilities have declined. Hundreds of conditions can cause dementia and people can also have multiple causes (known as mixed dementia). Alzheimer's disease is the most common cause of dementia in old age. Other common causes of dementia include strokes, head injuries, metabolic changes and infections. One reason why it is important to get a timely check-up is because many treatable causes such as vitamin deficiencies, alcohol abuse, thyroid deficiency or depression can mimic Alzheimer’s.

More and more reminder tools and other inventions are being developed to help people with early stage dementia. Do these entail a risk of faster degradation, because the mind will then not be trained anymore? Also, are there differences across the types of dementia? (Elizabet Okmen)

To date there is no evidence that the use of smartphone calendars or reminder tools raises a dementia person’s risk for faster deterioration – as long as the person continues to engage in other forms of mentally challenging activities. But this is a great question: as you suggest, the “use it or lose it” saying is very relevant to the brain.

There are dozens of varieties of dementia that each affect the brain uniquely and manifest with different clinical features. For example, some types of dementia may come on very rapidly (e.g. infections) while others may take decades (Alzheimer’s). One rare type of dementia, Benson’s syndrome, may spare memory but rob a person of their ability to recognize pictures and faces. That is why a neurological exam, brain scan and blood tests may be needed to tell the difference.

With the improving technology and science in medicine, every day we get closer to new treatment for many diseases. Are you feeling optimistic about finding a treatment for Alzheimer? If so, why? (Alban Vogel)

We need to double or triple our current investment so that we can rapidly test and bring to market new therapies. Yes, new technologies will help. For example a recently developed “Alzheimer’s in a Dish” model at Harvard is now allowing scientists to rapidly screen hundreds of potential therapies. The first human stem cell trial for Alzheimer’s is underway at University of Miami. I am optimistic that large ongoing clinical trials as well as global brain science projects, such as the Allen Institute Brain Atlas and Cell Types project, the Brain Initiative, the Human Brain Project, the Blue Brain Project and the China Brain Science Project, will not only help us better understand the causes of Alzheimer’s but also lead to better treatments.

Excluding medicinal treatments, what can carers do best for people with Alzheimer's? How can they best make them feel mentally comfortable? (Ally Bainton)

Carers should not only be supportive but try as much as possible to see things from the affected person’s perspective. A positive environment is very helpful – and can consist of things like soothing colors, personalized musical or movie playlists that bring back fond memories, providing utensils, phones and devices that are easy to use, and ultimately treating them with respect and dignity. New smart home technology, such as door sensors and wearables to track location, are beginning to allow affected seniors to live independently at home with a higher quality of life.