A seafaring mobile game could be a key to early Alzheimer’s detection, according to a recent study published in Proceedings of the National Academy of Sciences.
In the study a users’ gaming performance results were able to predict whether or not the participant had the gene linked to a predisposition for Alzheimer’s, called APOE4. This is in contrast to the neuropsychological episodic memory test, which found the results from the participants with and without the gene indistinguishable, according to the study.
"Our current findings show that we can reliably detect such subtle navigation changes in at-genetic-risk of Alzheimer's disease healthy people without any problem symptoms or complaints,” Michael Hornberger, a professor at the University of East Anglia’s medical school, said in a statement. “Our findings will inform future diagnostic recommendations and disease treatments to address this devastating disease.”
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Researchers zeroed in on how subjects performed on a way finding skill—or ability to solve spatial problems—in the ResearchKit-connected smartphone game, dubbed Sea Hero Quest. Using a regression model for how a subject performed on wayfinding distance in the game, researchers were able to correctly classify 71.3% of the cohort with the APOE4 genotype.
"We found that people with a high genetic risk, the APOE4 carriers, performed worse on spatial navigation tasks. They took less efficient routes to checkpoint goals,” Hornberger said. “This is really important because these are people with no memory problems. Meanwhile, those without the APOE4 gene travelled roughly the same distance as the 27,000 people forming the baseline score. This difference in performance was particularly pronounced where the space to navigate was large and open. It means that we can detect people who are at genetic risk of Alzheimer's based on how they play the game.”
Researchers did find that sex impacts wayfinding ability, with males outperforming females, but researchers were able to plot each person’s age, sex and educational level to match the subpopulation from the normal distribution of the UK population.
Researchers collected a big data set from 27,108 users from the Sea Hero Quest game. Next, researchers recruited 150 individuals between the ages of 55 and 75-years old. The subjects were tested for a history of psychiatric or neurological disease and a history of substance abuse. Eventually the researchers narrowed that group down to 60 participants, who were then tested for the gene. In that group 31 subjects had the APOE4 gene and 29 did not. Researchers then matched the groups to the benchmark data from the big data set of 27,108 individuals.
Alzheimer's disease the sixth leading cause of death in the United States, according to the Alzheimer's Association. The number of deaths from Alzheimer's is growing. In fact, between 2000 and 2017, the number of Alzheimers deaths increased by 145%, according to the association.
Early detection for Alzheimer’s can be difficult. Authors of the study noted that spatial navigation is a factor for identifying preclinical Alzheimer’s disease.
“Spatial navigation is a promising cognitive fingerprint for underlying Alzheimer’s disease pathophysiology and has been adopted by many high-profile clinical trials (such as the European Prevention of Alzheimer’s Dementia Consortium) to improve the sensitivity of neurocognitive testing and assess the efficacy of potentially disease-modifying treatments,” authors of the study wrote.
However, individual ability and variation can make it difficult to assess.
“A major challenge at this stage, however, is to understand how inter-individual and demographic factors affect spatial navigation to identify earliest pathological spatial navigation changes in [Alzheimer’s disease],” authors of the study wrote.
“Our results show that we can replicate previous wayfinding changes in APOE4 gene carriers; sex differences significantly impact on wayfinding behavior, but the effect of sex is negligible compared with APOE genetic risk; healthy [individuals] 'at-genetic-risk' of AD with no memory deficits can be distinguished on wayfinding measures on an individual level,” authors of the study wrote.