Detecting Alzheimer’s disease early can be challenging, especially in the pre-clinical stages before any symptoms are apparent. Brain changes associated with Alzheimer’s disease occur years and years before any symptoms are noticeable, and it is hypothesized that for future treatments to be most effective, giving these treatments as early as possible is best, before significant brain damage occurs. The challenge, then, is developing a way to identify pre-clinical Alzheimer’s disease so that treatment can begin as soon as possible.
Where does Alzheimer’s disease begin?
Alzheimer’s disease starts in an area of the brain called the entorhinal cortex.1 More specifically, it arises in the lateral entorhinal cortex (LEC), which can be thought of as a “gateway to the hippocampus.” The hippocampus helps with consolidating long-term memories, and if the LEC is compromised, other functions of the hippocampus can also be affected. As the disease progresses, Alzheimer’s spreads to other parts of the cerebral cortex, especially the parietal cortex, which is involved in spatial orientation and navigation.1
A cell phone game and Alzheimer’s disease
Researchers from Alzheimer’s Research United Kingdom, the University of East Anglia, University College London in the UK, and Deutsche Telekom collaborated on the development of a cell phone game, Sea Hero Quest, that might help researchers and clinicians identify who may be at risk for developing Alzheimer’s disease.2 Issues with spatial navigation and wayfinding are some of the earliest signs of Alzheimer’s disease, and the main focus of Sea Hero Quest is finding one’s way through mazes.
When looking at spatial navigation, however, there’s a lot of variation between individuals and their abilities. Some people are just better at navigating than others, and it’s helpful to look at various confounding factors. In a study published in the journal PNAS, scientists looked at participants who had the APOE genotype (one of the genes implicated in Alzheimer’s disease), and whether Sea Hero Quest could accurately distinguish those with APOE (labeled high-risk) from those who did not have APOE (labeled low-risk). The study found that although baseline navigation ability varied between men and women, sex did not interact with APOE.3 It was also found that using this game, high-risk pre-clinical cases could be reliably differentiated from low-risk participants using big-data spatial navigation benchmarks.3 This was in contrast to episodic memory tests generally used in clinical settings, which could not accurately or reliably differentiate between the two populations.3 These high-risk individuals not only had impaired spatial navigation tasks, but also took routes that were less efficient in the game.2
It is hypothesized that perhaps in the not-too-distant future, this data can be used to more accurately identify and classify spatial impairments in high-risk of Alzheimer’s disease individuals who are otherwise healthy, and also provide personalized, more individualized diagnostics and eventually treatment. It can also make diagnostic evaluation more efficient: according to the researchers, two minutes of playing the game is the equivalent to five hours of lab-based study.2 By identifying these problems at the pre-clinical stage, it offers the possibility of earlier treatment, which will likely be more effective. By the time an individual starts displaying symptoms, considerable damage to the brain has already occurred.
While this is very promising, this is an early study and more research needs to be done with pre-clinical diagnostic testing, as well as treatments in the pre-clinical stage. If you’re interested in learning more or seeing if you or someone you love could potentially participate in a similar clinical study, talk with your doctor.
Study Shows Where Alzheimer’s Starts and How It Spreads. Columbia University Irving Medical Center. https://www.cuimc.columbia.edu/news/study-shows-where-alzheimers-starts-and-how-it-spreads Published December 22, 2013. Accessed July 22, 2019.
Sharkey L. Could A Cell Phone Game Detect Who is At Risk of Alzheimer’s? Medical News Today. https://www.medicalnewstoday.com/articles/325103.php Published May 5, 2019. Accessed July 22, 2019.
Coughlan G, Coutrot A, Khondoker M, Minihane A-M, Spiers H, & Hornberger M. Toward personalized cognitive diagnostics of at-genetic-risk Alzheimer’s disease. PNAS. 2019; 116(19), 9285-9292. Doi: https://doi.org/10.1073/pnas.1901600116