Sleep IX

Alzheimer's is a scary term. When I was learning to be a yoga therapist, the doctor who taught us alzheimer's had a personal experience of it and she looked at us very sternly and said "i have no words to tell you how much it breaks you down - irrespective of whether you are suffering from it or if you are a caregiver".

Many many many suffer from this condition and the numbers are only increasing, not only as human life has stretched but also as total sleep time as decreased. Matthew claims that sleep can help us with diagnosis, prevention and therapeutics of the condition.

Over 60% of patients with Alzheimer's have at least one clinical sleep disorder. Sleep quality especially deep NRE sleep, deteriorates as we age. This causes a decline in memory - in the case of an Alzheimer's patient, memory loss is more exaggerated - sleep disturbance precedes the onset of the disease and therefore can act as a warning sign or even a contributor to it - therefore often they act in a self-fulfilling negative spiral that can initiate or accelerate the condition.

Alzheimer's disease is the build up of a toxic form of protein called beta-amyloid, which aggregates in sticky clumps or plagues within the brain - these are poisonous to neurons, killing surrounding brain cells. But this affects only certain parts of the brain and not others. 

The area of the brain that the plagues most affect is the middle part of the frontal lobe - the same region that generates the deep NREM sleep. It was not just a general loss of deep sleep, which is common as we age, but the very deepest of the powerful slow brainwaves of NREM sleep that the disease was eroding.  "Sleep impairment caused by amyloid buildup in the brain was more than just "normal aging". It was unique"

Despite Alzheimer's disease being typified by memory loss, the hippocampus - the memory reservoir of the brain - is not affected by the amyloid protein.

Through an experiment Matthew confirms that the elderly with highest levels of amyloid buildup in the frontal regions of the brain had the most sever loss of deep sleep and failed to consolidate new memories - overnight forgetting instead of remembering had taken place. But is it possible that a lack of sleep actually causes amyloid build-up in your brain to begin with?

Dr. Maiken Nedergaard, working with mice, found that a sewage network called the glymphatic system exists within the brain. It's name is derived from the body's equivalent lymphatic system, but it's composed of cells called glia.

Glial cells are distributed throughout the entire brain, just as the lymphatic system drains contaminants from your body, the glymphatic system collects and removes dangerous metabolic contaminants generated by the hard work performed by the neurons in your brain.

It is during sleep that this neural sanitization actually goes on full blast, alongside the deep pulsating rhythm of the deep NREM sleep, which leads to a more effective removal of the wastes from the brain. The purifying work of the glymphatic system is accomplished by the cerebrospinal fluid that that bathes the brain. 

Why only at night you say? Nedergaard found that the glial cells of the brain were shrinking in size by up to 60% during NREM sleep, enlarging the space around the neurons and allowing the cerebrospinal fluid to efficiently clean out the metabolic refuse of the day's neural activity - letting us wake up with a clean brain every morning.

One of the toxins the system eliminates is the amyloid protein. Without efficient sleep amyloid protein build up in the brain, in deep-sleep generating regions, attacking and degrading them. The loss of deep NREM sleep caused by this assault therefore lessens the ability or remove amyloid from the brain ta night resulting in greater amyloid deposits.

More amyloid = less deep sleep

Less deep sleep = more amyloid

Getting too less sleep in your adult life span will significantly raise your risk of developing Alzheimer's disease.