Brains of Young Adults With Alzheimer’s Risk
By Amy Norton
THURSDAY, Oct. 22, 2015 (HealthDay News) — Young adults who have an increased genetic risk for Alzheimer’s disease may already show differences in how their brains handle spatial navigation, a small study suggests.
“That is still unclear and needs to be investigated in further studies,” said senior researcher Dr. Nikolai Axmacher, of the German Center for Neurodegenerative Diseases, in Bonn.
But the hope, he said, is that the findings will improve researchers’ understanding of the earliest processes that lead to Alzheimer’s — the most common form of dementia.
And if the brain differences do turn out to predict Alzheimer’s disease years later, that information could be used to pinpoint high-risk people early, Axmacher added.
Other researchers said the findings were important, because everyone wants to find reliable biological signs that indicate a person has a high risk of Alzheimer’s later in life.
The study, published in the Oct. 23 issue of Science, involved 75 young adults, half of whom carried a variant of the APOE gene that is believed to boost the risk of Alzheimer’s.
It’s estimated that one in six people carry the variant, known as APOE4, Axmacher said. They have a threefold greater risk of Alzheimer’s than non-carriers do.
The researchers used an advanced form of MRI to study a brain area known as the entorhinal cortex, which contains so-called “grid cells.” Those cells, Axmacher explained, are important in spatial navigation — one of the first skills to go awry when Alzheimer’s begins.
The team tracked activity in those grid cells as study participants navigated a “virtual” task that gauged their spatial memory: They had to remember the spatial location of objects in a virtual arena, then place those objects in the correct place.
It turned out that, on average, the APOE4 carriers showed less functioning in their grid cells during the task, versus young adults who did not carry the gene variant.
Still, both groups performed similarly on the test.