Frequently Asked Questions

What are age-related neurodegenerative diseases?

Neurodegenerative brain diseases can be defined as progressive diseases of the nerve cells in the brain that occur more frequently with increasing age. The most common age-related diseases are dementia, Alzheimer’s disease, and Parkinson’s disease. Around 8.5 million people worldwide are affected by Parkinson’s disease and 55 million by Alzheimer’s or other forms of dementia. With the higher life expectancy, these numbers will increase significantly in the coming years.

Most people affected by age-related neurodegenerative diseases are older than 60, although younger people could also be affected. Depending on the condition, various mechanisms can lead to the premature ageing of nerve cells in the brain which progresses with time. Common symptoms are memory problems, changes in character, general slowing down, stiffness and tremor. There is no cure for most age-related neurodegenerative diseases, and the triggers are often unknown.

How are age-related neurodegenerative diseases diagnosed?

Presently, the diagnosis is primarily made clinically, for example, by a doctor’s consultation with a physical medical examination and with additional exams, such as a detailed (neuro)psychological test or a mobility test. Imaging is often done (MRI or computer tomography) to exclude other treatable causes of the symptoms or to confirm the diagnosis.

Early signs of age-related neurodegenerative diseases can be cognitive deficits (memory disorders, disorientation, behavioural changes, and personality changes) and movement disorders (stiffness, tremor, slowing down, changes in writing, or decreasing facial expressions). Other symptoms include smell disorders, depression, constipation, and sleep disorders.

Why do we want to diagnose age-related neurodegenerative diseases at an early stage?

One of the reasons why there is no cure for most age-related neurodegenerative diseases is related to the time of diagnosis. At this stage, a large proportion of the brain’s nerve cells have already been irretrievably lost. In Parkinson’s disease, for example, 50-60% of the important dopamine-producing cells have already lost their function by the time of the diagnosis. The progressive loss of neurons already begins many years before the first symptoms appear.

Unfortunately, little is known about this very early phase of the disease. If we could detect affected individuals early, we would be a small step closer to our research aim of slowing, stopping, or even reversing the disease process.

How might we identify people at increased risk for age-related neurodegenerative diseases before symptoms appear?

Previous research indicates that anxiety, depression, forgetfulness, personality changes, sleep disturbances, constipation, or olfactory deficits may occur up to 20 years before the neurodegenerative disease can be diagnosed. Many people above 60 years are likely to have one or another of these symptoms without developing a neurodegenerative disease later. However, we could identify individuals at exceptionally high risk for age-related neurodegenerative diseases by identifying people exhibiting several of these symptoms.

About the Healthy Ageing study

The Healthy Ageing study is a unique research study that aims to identify people at high risk for age-related neurodegenerative diseases, such as dementia or movement disorders before these diseases develop.The study will consist of a combination of simple online focusing on the factors associated with an increased risk of developing an age-related disease. The aim is to find out whether the overall result of these tests can tell us anything about those.

Will this study predict who will develop an age-related neurodegenerative disease?

No. This study aims to optimise the assessment of risk factors for certain neurodegenerative diseases in a group of people; it is not designed as a tool to predict the evolution of the state of health of single participants. Although there is already knowledge about the early stages of age-related diseases, it is currently impossible to determine precisely who will develop a neurodegenerative disease later. The results of this study will help develop more reliable methods to identify people at increased risk.

What is unique about the Healthy Ageing study?

This study is innovative because it is primarily done online. This means that participants do not have to leave their homes to participate, and we will be able to compare risk factors across multiple countries quickly and efficiently. We hope that in this way, more people will be able to participate in this study and possibly benefit from its results. It will also target the earliest known symptoms of these types of diseases.

Who can participate in the study?

We are looking for people between 50 and 80 years old with internet access, without any known age-related neurodegenerative disease, and who currently live in Luxembourg or the Greater Region. Nonetheless, people with age-related neurodegenerative diseases in their families are welcome to join.

What countries/regions are part of the Greater Region?

The Greater Region is composed of the following countries and regions:

  • Luxembourg;
  • Belgium (Wallonia, the German-speaking community);
  • France (Lorraine);
  • Germany (Saarland, Rhineland-Palatinate)

What will happen if I participate in the study?

After agreeing to participate in this study by filling out the electronic Consent Form on the secure study website, you will be asked to provide your date of birth and contact details. Your personal identification information will then be used to re-contact you if you qualify for the next steps.

The first step consists of an online questionnaire asking for medical information and questions on demographics and socio-economics, well-being, quality of life, cognition, and sleep that may influence the risk of developing age-related diseases. The questionnaire takes around 20 minutes to complete. Please have information on your medication at hand as there are specific questions on the medication you are currently taking in the survey.

Based on the online questionnaire answers, the study team will contact a subset of participants to propose a smell test to be performed at home. Some of these participants may be invited to come to the clinic for a medical examination and to undergo other tests (see below). However, if you are contacted, it does not mean that you are at an increased risk, as we will contact participants with different risk scores (low- or high-risk).

Finally, if initial analyses of the overall data provide promising results, the study might be prolonged, and participants might be asked to repeat the online tests annually.

What happens if I am one of the participants invited for further examinations?

Participants invited to perform a smell test at home and/or undergo a medical examination will be contacted after an initial evaluation of the data. Participation is voluntary for all steps. If you are invited for an appointment at our Research Clinic in Strassen, in Luxembourg City, you will be invited to perform a clinical examination and donate samples:

  • Medical interview;
  • Medical examination;
  • Olfactory tests and memory tests;
  • Blood, saliva, and urine collection.

You will have the possibility to donate a stool sample as well. The clinical team will give you a dedicated collection kit to take home, with the help of which you can collect a small amount of stool and send it to us by mail.

For this part of our study, the clinical examination and sample collection will be in the context of the related established Biomaterial collection for neurodegenerative disease research (ND Collection), approved by the Ministry of Health and with a favorable opinion from the National Research Ethics Committee (CNER). This national research collection was established in 2015 by the Integrated BioBank of Luxembourg (IBBL), part of the Luxembourg Institute of Health (LIH), and the Luxembourg Centre for Systems and Biomedicine (LCSB), part of the University of Luxembourg (UL) in the context of the National Centre of Excellence in Research on Parkinson’s Disease (NCER-PD).

The ND Collection aims to collect clinical data and samples from individuals with and without neurodegenerative disease to answer the most urgent research questions, such as defining disease markers and studying mechanisms causing premature neuronal ageing.

The clinical examination will, of course, take place after separate clarification and consent. The in-person examinations will take about one morning, and you can also refuse specific individual tests.

Are there any possible risks and side effects to the participation?

There are no anticipated risks of participation. For participants invited for in-person visits, they will be asked to provide blood, urine, saliva, and stool samples. There are minimal known risks associated with a blood draw. Our study is designed as a non-invasive study; however, we feel that the minimal risk of blood sampling is justified compared to the potentially high informative value of the analyses. Collecting stool, urine, and saliva is done by yourself and is risk-free.

What are the benefits of being part of the study?

There is no direct benefit from participating in this study, and there will be no compensation or remuneration given for your involvement or any subsequent developments resulting from the study. However, your participation is important because you will provide information to improve research on neurodegenerative diseases, such as finding ways to diagnose age-related neurodegenerative diseases at the earliest possible stage. This would potentially pave the way for better treatments and cures, benefiting people worldwide with age-related neurodegenerative diseases.

Are there costs associated with your participation?

There are no costs for you to participate in this study.

What if I change my mind and don’t want to participate anymore?

If you decide to withdraw your participation, you can do so at any time, without giving a reason and without any further consequences or disadvantages for you.

Why is the survey not available in Luxembourgish?

For medical or psychological questionnaires to be used in research in a specific language, it is essential that they are standardised and validated. This is necessary to reach the highest research quality standard to produce comparable answers among the international research community. Such research surveys are generally established in the languages spoken in different countries globally. Unfortunately, such standardised questionnaire versions do not exist in the Luxembourgish language. Therefore, we have provided standardised versions of the questionnaires in the four most used languages in Luxembourg and the Greater Region: French, German, English, and Portuguese. We thank you for your understanding!

Can I also participate in the online survey in person or by phone?

You can only fill out the questions online. If you require assistance filling out the survey form, you can call the study team (+352 621 789 769), who will gladly assist and guide you.

I don’t live in Luxembourg or the Greater Region. Can I participate?

The study can only include people living in Luxembourg or the Greater Region between 50 and 80 years old.

I am younger than 50 or older than 80, but one of my family members has/had a neurodegenerative disease. Can I participate?

The Healthy Ageing study is designed for an age group between 50 and 80 years only. If you suspect that you have a neurodegenerative disease, we suggest that you consult your treating physician.

I have been diagnosed with a neurodegenerative disease and am in the target audience (50-80 years old). Can I still participate in the study?

People with a known diagnosis of age-related neurodegenerative diseases such as Parkinson’s or Alzheimer’s disease or other neurological movement disorders, dementia, stroke, or amyotrophic lateral sclerosis cannot participate in the study.

However, you can still support our research by participating in the Luxembourg Parkinson Study. For any questions, feel free to contact our Parkinson’s Research Clinic at +352 44 11 4848 or

How long does it take to complete the survey?

Completing the questionnaire will take approximately 20 minutes. When starting the survey you will first receive a personalised code – it is important to write it down or save this code.

Can I stop the survey and continue it later?

Ideally, you should try to complete the survey in one go. If you cannot complete the entire survey in one sitting, you can interrupt at any time and come back at a later time using your code.

Will I receive my personal risk score?

Based on the online questionnaire answers, the study team will invite a subset of participants with particularly high or low risk scores to participate in subsequent parts of the study.

In which languages can I answer the survey?

The online survey is available in French, German, Portuguese, and English. Similarly, communication in all of the above languages will be possible at all other stages of the study. Our study team speaks all four languages above as well as Luxembourgish.

Who can I contact in case of issues with the survey or any further questions on the study?

In case of further questions, you can call the helpline of the Luxembourg Healthy Ageing Study team (+352 621 789 769, Mon. – Fri. 08:00 - 17.00h) or send an email to

If you have any other questions, please contact the Parkinson’s Research Clinic: +352 44 11 4848

How will my data be used?

You are invited to (i) share data by completing a questionnaire for this study (primary use) and (ii) authorize the subsequent use (secondary use) of data concerning you (except for your direct identifying data) for future medical research. If you give your consent for future research by ticking the box provided for this purpose in the consent form, this means that the University of Luxembourg/ Luxembourg Centre for Systems and Biomedicine (UL/LCSB) and the Luxembourg Institute of Health (LIH) will be able to make your data available for use in other medical research programs conducted by the UL/LCSB and LIH or by other duly authorized national or international organizations, for academic and/or commercial purposes, for research in the area of neurodegeneration or other biomedical research domain, depending on the options you select on the consent form.

In Luxembourg, the Healthy Brain Ageing (HeBA) project is organised under the framework of the National Centre of Excellence in Research on Parkinson’s Disease (NCER-PD), in collaboration with the University of Luxembourg and the Luxembourg Institute of Health. The international partners involved in HeBA are the Paracelsus-Elena-Klinik in Kassel, the University Medical Centre in Göttingen (Germany), the Innsbruck Medical University (Austria) and the Hospital Clinic de Barcelona (Spain). This study is financed by the Michael J Fox Foundation..