Don’t sleep on this troubling symptom of Alzheimer’s.
Despite primarily affecting people over the age of 65, the most common type of dementia can be detected through early warning signs like poor memory and a short attention span.
Now, a new study led by the University of Kentucky offers a major clue to the link between Alzheimer’s and a common signal of cognitive decline.
Brain function and sleep are strongly connected, as those who don’t get enough slow-wave or deep sleep are often at a higher risk of developing dementia.
But recent research explains why those with Alzheimer’s often experience insomnia, and it’s due to the toxic build-up of tau protein in the brain.
These tau tangles or clumps damage and disrupt communication between brain cells, causing the cognition and memory issues typically associated with Alzheimer’s disease.
Tau can also “hijack” the brain’s energy supply, keeping neurons excited and making it more difficult to fall asleep.
“It’s like a petulant toddler who just won’t calm down and go to sleep,” said principal investigator Shannon Macauley.
The researchers studied tau-related disease models in mice, discovering a switch-up in how the brain creates energy.
When tau builds up abnormally, the brain goes into overdrive and produces glutamate, a neurotransmitter that stimulates neurons and helps with learning and memory, instead of using sugar to make energy in the normal way.
“The brain is hijacking all your glucose to make glutamate over and over again, keeping the system awake and preventing it from reaching the deep, restorative stages of sleep necessary for recovery and memory formation,” Macauley said.
Both tau and glutamate are usually beneficial, as tau helps stabilize nerve cell structure. But too much of both keeps the brain — and you — wide awake.
Notably, the researchers noticed the brain making glutamate even before tau started clumping, which may explain why poor sleep can precede Alzheimer’s by years.
They also noted the cyclical process of the degenerative disease disrupting sleep, which can worsen symptoms.
The study also suggests that medications for epilepsy or type 2 diabetes that modify the brain’s metabolism could lessen hyperactivity and improve sleep while slowing progression of the disease.
This study comes as there’s increasing evidence that lifestyle factors can cause or worsen Alzheimer’s, such as physical activity, smoking, chronic stress and poor sleep.
