Is precision medicine the answer to Alzheimer’s disease?

As a neuroscientist, I’ve dedicated my life to understanding the brain and how it processes memories. I was one of the lead researchers that discovered how eye-tracking technology can be used to identify dysfunction to the hippocampus before symptoms of Alzheimer’s disease start, and I’m so happy that Neurotrack has made that technology available to consumers via the Imprint Check-Up.

While new discoveries are exciting, I often think there’s a lot to be learned from reframing how we think about longstanding problems. For example, I’ve recently proposed that the scientific community ought to consider thinking of Alzheimer’s disease as a spectrum disorder. In a spectrum disorder, many individuals are diagnosed with the same condition, but they do not all have the same symptom profile; some will have symptoms A, B and C, while others will have symptoms B, C and D, still others will have A, C and D, etc. Currently, the most well known spectrum disorder is autism.

Alzheimer’s as a spectrum disorder

A number of studies have begun to reveal varied patterns of behavioral changes and abnormalities in patients with Alzheimer’s disease. Many of these studies point to the fact that not all patients exhibit the full range of behavioral abnormalities associated with Alzheimer’s, and many behavioral changes do not seem directly correlated with cognitive impairment. For example, in a study of behavioral changes in Alzheimer’s where the frequency and severity of ten commonly reported behaviors were assessed, it was reported that the most common behavior was apathy, exhibited by 72% of the patients, followed by agitation (60%), anxiety (48%), dysphoria (38%), and disinhibition (36%). Agitation, dysphoria and apathy were significantly correlated with cognitive impairment, but many other behavioral problems were not.

These findings point to the idea that despite having the same diagnosis, individual Alzheimer’s patients can have quite different behavioral problems, and while some behavioral changes can be linked to a defining feature of Alzheimer’s, namely cognitive changes, others cannot.

Patterns of behavioral change can vary from patient to patient, even within a diagnostic category, e.g., mild, moderate or severe Alzheimer’s. It is in this sense that some experts are calling for Alzheimer’s to be described as a spectrum disorder, rather than as a disease, with an easily identifiable set of symptoms.

The promise of precision medicine

Why does it matter whether we think about Alzheimer’s as a “one-size-fits-all” disease or a spectrum disorder? Because how we think about a disease impacts how we treat it.

Precision medicine, sometimes called personalized medicine, refers to the tailoring of medical treatment to patients, depending on their individual characteristics and the characteristics of their diagnosed disease. The most publicized research into precision medicine has focused on cancer treatment — investment in the treatment of pancreatic cancer is a recent example.

I believe that because the behavioral changes experienced by Alzheimer’s patients can be so diverse, precision medicine may have a lot to offer sufferers. However, it can only be effective if we work harder to understand the many different characteristics of Alzheimer’s and whether they correlate with people’s unique medical history. There are a number of risk factors associated with Alzheimer’s disease, both genetic and environmental. For example, certain genes make people much more likely to develop Alzheimer’s, but equally, people who have experienced traumatic brain injury (TBI) are also at higher risk. If we can understand how the different characteristics of the disease interact with someone’s unique medical history, we will then be able to design tailored treatment plans that have a higher success rate than currently possible.

What precision medicine might look like for patients with Alzheimer’s disease

The failure rate for Alzheimer’s drugs trials has remained stubbornly high. But the disappointment surrounding the failure of drug trials has obscured the more successful results in research aimed at prevention. We know that lifestyle can play a significant role in brain health: participants in the FINGER study based in Finland, which involved a range of lifestyle changes, saw a 150% improvement in brain processing speed and an 83% improvement in executive functioning. Participants in the MIND diet study, which tested the impact of diet on memory health, saw a 53% reduction in their risk of developing Alzheimer’s disease.

While it could be years or decades before a drug comes to market, changes to lifestyle can be made immediately by those at risk of, or diagnosed with, Alzheimer’s disease. If we can learn more about how environmental and genetic factors impact the behavioral changes exhibited by patients, we may be able to create more targeted and effective treatment programs. If we couple this with new brain monitoring technology, made possible by our research into eye-tracking, we could get patients on a treatment program while they’re at risk of developing the disease, rather than waiting for them to develop symptoms.

A huge shift

Changing how we think about Alzheimer’s disease and describing it as a spectrum disorder would be a huge shift for the medical community, patients and their caregivers. But given the many faces of the disease, I believe this shift is a critical way to reveal the new insights needed to improve treatments and prevention programs. If precision medicine is to live up to its promise, we need the insights into the causes and the symptoms that can help us develop the targeted treatment every patient deserves.

Dr. Stuart Zola
Dr. Stuart Zola

Stuart Zola, PhD - Dr. Stuart Zola is one of the United States’ leading neuroscientists, and the researcher behind Neurotrack’s Imprint Check-Up.