Interview with Prof. Martin Rossor, NIHR National Director for Dementia Research and Principal Research Associate at the UCL Queen Square Institute of Neurology

Alzheimer's disease, a neurodegenerative condition that slowly and progressively destroys brain cells, has a severe impact on individuals as well as the people around them. Moreover, it is often challenging to detect this condition before the emergence of clear symptoms. In the light of this, Prof. Martin Rossor, NIHR National Director for Dementia Research and Principal Research Associate at the UCL Queen Square Institute of Neurology, shares his views on some of the challenges in detecting Alzheimer’s as well as the opportunities provided by digital health technologies. 

What is Alzheimer's disease (AD) and how is it linked to developing AD dementia? 

AD describes a clinical clinicopathological disorder that is characterised by progressive impairment in cognition, particularly affecting memory. The brains of those with AD show the hallmarks of the disease described by Alzheimer, which are the senile plaques and neurofibrillary tangles. Dementia is a general term used to describe cognitive impairment that is sufficiently severe to interfere with everyday activities. AD dementia is thus dementia due to Alzheimer's disease and will occur as the disease progresses. However, the disease does have a long period of development, probably extending up to 10 years before symptoms become clear. 

How is AD dementia affecting people in the UK and in Europe? And particularly, what are the implications of AD dementia for countries with ageing populations?

Since we currently have no cure for AD it is progressive and will in the vast majority of cases lead to dementia or severe impairment. This not only affects individuals with the disease but also spouses and family. Moreover, AD as well as AD dementia are also common as we get older. Estimated numbers for dementia, all forms and causes included, are at least 1 million in the UK and more than 9.5 million in Europe. This also has major economic impact. According to the World Health Organization (WHO), the annual costs of dementia are approximately €275 billion (US$ 300 billion) for the WHO European Region.

Could you elaborate on the current challenges in detecting AD before the emergence of clear symptoms?

There are a number of challenges in detecting AD before clear symptoms emerge. A major issue is what we mean by AD in this context. Currently, AD is a clinicopathological concept, i.e., a combination of clear symptoms and underlying plaques and tangles. The identification of tau and amyloid deposition in the brain is now feasible with PET imaging and for amyloid also identifiable in CSF by lumbar puncture. However, we are still not able to predict reliably the prognosis following detection of tau and amyloid. This is particularly true in the elderly. Moreover, in the absence of a treatment early detection outside a research context may be of limited value or, in some instances, harmful.

Could you elaborate on the link between lifestyle factors and the risk of developing AD dementia? 

The two major risks for AD are genetic and advanced age. In very rare instances, AD can be inherited as an autosomal dominant disorder due to mutations in the presenilin and APP genes. The APOE4 genotype also confers an increased risk but is neither sufficient nor necessary to cause AD. Age is the other major factor, but AD is less clearly defined in the elderly and usually coexists with vascular disease and other neurodegenerative processes. A number of lifestyle factors have been identified that lead to an increased risk of dementia, rather than specifically to AD. These include smoking, hypertension, diabetes and obesity. The general rule is that what is good for the heart is also good for the head. Improvement in managing high blood pressure may be linked to the reported reduction in some countries of the incidence of dementia, although the prevalence is expected to increase with increased longevity. Many lifestyle factors are modifiable, but it is not yet known to what extent they may modify Alzheimer's Disease. There is an excellent review by Livingstone and colleagues (

What are, in your opinion, the main challenges and opportunities associated with using digital health technologies to enhance the early detection of AD?

There are many opportunities from understanding early symptoms, through to providing care and support. Testing individual domains of cognition using tests of graded difficulty is the standard approach to assessment of cognitive impairment. This is most powerful when serial assessments can detect change within an individual. With the ubiquity of data from phone usage through to shopping patterns, there is an opportunity to detect change in how an individual interacts with a complex environment. This has opportunities for research but also for support when in the early stages of vulnerability. For example, in managing financial matters whereby subtle changes in decisions can alert family members. With more advanced disease, digital health technology via the internet of things gives the opportunity for individuals to maintain independence. The major challenge is to ensure security, autonomy and privacy in the handling of individuals data.