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Hello everyone, SCIENSPOT is a podcast that shines a spotlight on the latest scientific
technology from Japan. Your host is REN from SCIENTALK.
アルツハイマー病の超早期検出
Today on SCIENSPOT, I am exploring a breakthrough in detecting Alzheimer's disease. A joint
research group from several Japanese universities, including Fujita Health University, Gakushuin
University and National Institute for Contemporary Science and Technology, has shown that combining
3D virtual reality goggles with blood tests could enable ultra-early screening for Alzheimer's
disease.
Alzheimer's disease, a progressive neurodegenerative disorder, is a growing concern globally as
our population age. Currently, there is no cure to stop its progression once symptoms
appear. This is why identifying the disease in its ultra-early stage before symptom manifests
is crucial for timely intervention and potential prevention.
Traditional diagnostic methods for Alzheimer's often focus on assessing higher brain functions
related to memory, primarily linked to the hippocampus region of the brain. However, the
earliest pathological changes in Alzheimer's are actually known to begin in the endothelial
cortex, a brain area located just before the hippocampus.
One vital function of the endothelial cortex is path integration. Path integration is our
ability to estimate our current position and orientation by integrating self-motion cues
アルツハイマー病の早期検出
like visual, vestibular, and proprioceptive information without relying on external landmarks.
It's like having an internal GPS that tracks your movement and updates your location in
your mind, even if you can't see where you're going.
Grid cells in the medial endothelial cortex are thought to be particularly involved in
this. This study's core idea was to detect functional changes in the endothelial cortex
before structural damage occurs or memory problems linked to the hippocampus become apparent,
thereby enabling earlier detection of Alzheimer's diseases.
The research team recruited 111 healthy adults aged 22 to 79 to evaluate their path integration
ability using a unique 3D VR navigation task. Participants wore VR goggles and entered a
20-virtual-meter circular arena with a minimal surrounding scenery. In this virtual space,
they were asked to move from a starting point to point 1, then to point 2, and finally to
return accurately to the starting point. This was repeated three times and the average error
distance, how far they deviated from the starting point, was measured.
Imagine trying to retrace your steps perfectly in a dark room, relying solely on your internal
sense of movement. The error distance would be how far off you were from your starting
mark. A larger error distance suggested a potential issue with path integration.
In parallel, blood tests were conducted to measure various biomarkers associated with
アルツハイマー病とバイオマーカー
Alzheimer's disease. Biomarkers are indicators in the body that can reveal the presence or
progression of a disease. Three key biomarkers were particularly focused on. The first one is
p-tau-181, a modified form of tau protein that accumulates in the brain in early Alzheimer's.
It's measurable in the blood and typically rises above 2.2 picograms per milliliter when
any pathology is present. Think of it as a very specific early warning signal for Alzheimer's.
The second one is GFAP, glenal fibrillate acidic protein. A protein released from
astrocytes brain support cells, its levels in the blood are known to increase with the
accumulation of amyloid beta, another abnormal protein in AD. It's like a fire alarm indicating
inflammation in the brain. And the final one is NFL, neural filament light chain. A protein
released into the blood when nerve cells are damaged, it's a general indicator of neuro
degeneration. This biomarker signals general damage to brain nerve cells. The results were
quite remarkable. The error distance measured in the VR navigation task showed a significant
correlation with age and blood levels of p-tau-181, GFAP, and NFL. This means that
individual who performed worse on the VR task generally had higher levels of these Alzheimer's
related biomarkers. Further analysis using multivariate analysis revealed that p-tau-181
and GFAP were independently associated with error distance even after accounting for age.
アルツハイマー病の早期検出
When machine learning was employed to determine the most important predictor of error distance,
p-tau-181 emerged as the most crucial factor. Crucially, error distance alone could identify
elevated p-tau-181 level, which indicated probable Alzheimer's disease pathology with
very high accuracy. The diagnostic performance represented by the area under the curve was
impressive at 0.86. This means the test could creatively identify approximately 86 out of
100 people with a sensitivity of 91.7% and a specificity of 77.8%. It's almost as if your
performance in a VR game could predict your blood test results. The study also leaked a structural
change in the brain using MRI, specifically the thickness of the entahinal cortex. While
it showed a negative correlation with age and error distance, this significance disappeared
after adjusting for age. This suggests that the VR test might capture factual changes in the brain
even before detectable structural changes occur. It's like detecting a subtle electrical wiring
issue in a house before the world starts to clock. This research process is a new screening
strategy that combines a non-invasive, quick, and low-validance 3D VR navigation test with
blood biomarker analysis to potentially detect ultra-early changes associated with Alzheimer's
diseases. While not yet ready for clinical use, if implemented, this could lead to VR tests
アルツハイマー病の早期検出
becoming a part of routine health checkup, allowing us to identify early signs of Alzheimer's even
before symptoms appear. Early intervention could potentially slow the progression of the disease
or enable preventive measures. This research brings significant hope for the future of combined
Alzheimer's disease. The research group plans to further investigate annual changes in error
distance, predict brain atrophy, clarify the relationship with more detail at how PET
scans, and ultimately aims for the social implementation of this non-invasive screening
method, making it accessible to everyone. That's all for today's SciencePod. It's exciting to imagine
how VR technology, once primarily for entertainment, could become a powerful tool for medical diagnosis,
helping us navigate these challenges of diseases like Alzheimer's. This podcast is broadcast in
both Japanese and English. I invite you to listen to the podcast and post your thoughts with the
hashtag SciencePod. Thank you for listening and see you next time.
