The Need for Sleep in the Fight Against Alzheimer's
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Time to read 5 min
Until recently, Alzheimer’s had been somewhat neglected by mainstream culture. And indeed, why such a debilitating, crippling condition had previously been ignored for so long, will probably elude us for many decades to come.
However, with the ageing baby boomer population reaching 65-plus in record numbers, and numerous high-profile individuals documenting their experience with the condition, from the late author Terry Pratchett to Monty Python’s Terry Jones, our understanding of the degenerative neurological condition has evolved rapidly in recent years, as have the attempts to tackle it.
Understanding Alzheimer's: The Leading Cause of Dementia
Alzheimer’s is the most common cause of dementia and accounts for 60% to 80% of dementia cases.
Dementia itself is the general term for a gradual decline in mental capacity across multiple core mental functions, including communication, visual perception, reasoning and memory. A progressive disease, dementia worsens over time, beginning with mild memory loss before eventually developing into an inability to communicate and converse.
Alzheimer's is a specific form of dementia, usually manifesting itself in each patient through impaired thought, impaired speech, and confusion.
Without adequate support, patients with Alzheimer’s greatest struggle will come in the form of struggling to adapt / respond to their environment, before becoming unable to perform basic tasks essential to their survival. Those with Alzheimer's for example, live an average of eight years after their symptoms become noticeable to others, and is the sixth leading cause of death in the United States.
As of yet, there is no cure for Alzheimer’s, despite the recent upsurge in public recognition for the condition. Current treatments cannot stop Alzheimer's from progressing, and can only temporarily slow the worsening of symptoms.
That’s why scientists all over the world have devoted themselves to not merely finding a cure for the disease, but also, finding what precisely causes the condition, in the hope of preventing the next generation, and generations beyond that from developing it.
That’s Where Sleep Comes In
Sleep and memory are complex phenomena that are still not entirely understood. However, the two are most certainly linked with one another.
First, sleep deprivation is known to negatively impact upon one’s ability to be attentive, and be capable of absorbing new information. Second, sleep is pivotal to the consolidation process of new information.
It’s because of this connection that many have previously assumed that there existed a link between poor sleep and dementia, and more specifically, Alzheimer’s. Could the progressive neurological disorder be due to complications in the consolidation process that occurs whilst we’re asleep? And if so, does this happen to occur at a specific stage within sleep?
The Science Behind It
As we age, our sleep gradually gets worse. In particular, our NREM (non-rapid eye movement) or ‘deep’ sleep, which is when most of our memories are consolidated. However, whereas previously the relationship between sleep disruption and memory loss were considered merely a matter of correlation, scientists would now argue that sleep disruption and Alzheimer’s work in a circle-like formation, often initiating and accelerating one another.
For many years, Alzheimer's has been associated with the build-up of a toxic form of protein called beta-amyloid, which collects within the brain. Not only do these beta-amyloid 'plaques' or 'clumps' kill brain cells, but perhaps more importantly, they congregate in the middle part of our brain’s frontal lobe - IE. the brain region most vital to deep-NREM sleep. What's more, a study conducted by Matthew Walker (author of the international bestseller, Why We Sleep: The New Science of Sleep and Dreams) in 2007, suggested that these beta-amyloid plaques manage to impair one’s deep-NREM sleep, grinding away at the very region of the brain that is responsible for generating this particular stage of sleep.
Maiken Nedergaard and David Holtzman have since gone further, specifically exploring whether poor sleep at all, at any stage in life, could increase the level of beta-amyloid protein in the brain, and thereby presumably, the chances of Alzheimer’s in later life.
It’s common to associate Alzheimer’s disease and dementia with older people, but the condition is diagnosed in younger people too. An estimated 42,000 younger people (below the age of 65) have "young-onset dementia" in the UK.
Working with mice for instance, Nedergaard found a cleansing network within the brain called the ‘glymphatic system’, responsible for breaking down harmful metabolic debris generated by our neurons, using cerebrospinal fluid. Moreover, the glymphatic system was at its most vibrant during NREM sleep, expelling 10 - 20 times the amount of harmful metabolic debris as it did during the day, including the beta-amyloid protein. In many ways, the glymphatic system’s cerebrospinal fluid is the most efficient night cleanser we could possibly ask for.
This was then combined with the work of David Holtzman, which involved depriving otherwise healthy adults of their deep-NREM sleep against a control group. Without their glymphatic system working at the same efficiency, it was discovered that those who had been unable to enter deep-NREM sleep tended to shows signs of more Alzheimer’s-related amyloid in their cerebrospinal fluid. To the likes of Walker, Holtzman and Nedergaard, it was obvious that a lack of deep-NREM resulted upon more toxic beta-amyloid protein in your brain.
And thus, the vicious cycle: more beta-amyloid protein results in less deep sleep, only for less deep sleep to help produce more beta-amyloid protein.
How Can We Win The Fight?
As previously mentioned, poor quality sleep is not the only thing that can help prevent the onset of Alzheimer’s. And even now, the precise extent to which investing in the prioritisation of high-quality rest could aid in the fight against Alzheimer's, remains unclear.
But then, what do we have to lose? The risk or developing diabetes, obesity, stroke, heart disease and even cancer have each been shown to increase following a history of sleep deprivation. To have Alzheimer's now added to that particularly unfortunate list, should therefore only heighten our attention to the seemingly unending health benefits attached to high-quality sleep. Writing in The Observer in 2015, Terry Pratchett spoke of his hopes for the future, in the fight against Alzheimer's. "I believe the D-day battle on Alzheimer’s will be engaged shortly and a lot of things I’ve heard from experts strengthen that belief. It is a physical disease, not a mystic curse; therefore it will fall to a physical cure. There’s time to kill the demon before it grows." For anybody who has developed the disease, or indeed, seen a family member or loved one succumb to the condition, the heartache, pain and stress is immeasurable. And unfortunately, sleep is not the only solution to eradicating this particular "demon" from the modern world. But we must acknowledge the fact that it can help.
For more information on dementia and Alzheimer's, click here to visit the Alzheimer's Society website.
