Preventive Neurology

Photo by S L on Unsplash Human biology is systems biology; perturb one aspect of human biology and it will have downstream effects, which can be noted throughout the body. As you know sleep is critical for brain health; if you have poor sleep hygiene you are putting yourself at greater risk of developing dementia when you get older. Why?  In this study of cognitively normal older Chinese adults, spinal fluid soluble TREM2 (sTREM2) was associated with self-reported poor sleep hygiene using the Pittsburgh Sleep Quality Index. sTREM2 is shed from activated microglia or macrophages and is thought to be a marker of microglial activation. The implications are that this association may be causal, i.e. poor sleep is pro-inflammatory, both in the periphery and central nervous system and the latter contributes to driving neurodegeneration. Could improved sleep hygiene be anti-inflammatory? Or is the microglial activation simply a response to poorer clearance of CNS debris, which occurs when...

I had a terrible night last night. One of my patients who has been under my care for over a decade was admitted to a district hospital with life-threatening sepsis and has to have emergency surgery. It is touch and go if this patient will survive. I kept tossing and turning and rehearsing events that led up to their admission and kept wondering if anything could have been done to prevent the sepsis from progressing to a stage when it required surgery. The result is I had a very poor night’s sleep and feel terrible this morning; irritable, tired, groggy and foggy as if I have a hangover. What damage has this caused? Photo by engin akyurt on Unsplash It is clear that sleep is a physiological must; acute sleep deprivation is a major life-threatening stressor and kills. This is why it is used as a method of torture. Chronic sleep deprivation is also a stressor and also kills, only more slowly. The paper by Eide and colleagues below shows how one night’s sleep deprivation impairs the brain...

The role sleep plays in normal human brain physiology is becoming more clear as the link between abnormal sleep and dementia gets stronger. Here is yet another epidemiological study linking reduced sleep in middle age to a higher risk of dementia. Quin Stevenson on Unsplash Is the association between reduced sleep and dementia causal or is it due to reverse causation? Sleep is required to consolidate memories and to allow the brain to cleanse itself, i.e. flush out all the intracellular debris that could aggregate to cause Alzheimer’s disease. Therefore, sleep deprivation by impairing memory consolidation and not allowing you to clear the brain's intracellular debris properly could lower your threshold for developing dementia in the future. Reverse causation states that people who are destined to develop dementia have pathology that starts decades before dementia manifests, for example, amyloid deposition and neurofibrillary tangles. The pathology affects parts of the brain that c...

Kinga Cichewicz on Unsplash The study below found that people who experience unconscious wakefulness most often and for longer periods of time had nearly double the risk of dying from cardiovascular disease during an average of between 6 and 11 years’ follow-up when compared to the risk in the general population. The association was particularly strong in women and less clear in men. Unconscious wakefulness also referred to as cortical arousal, is a normal part of sleep. It occurs spontaneously and is part of the body’s ability to respond to potentially dangerous situations, such as noise or breathing becoming obstructed. A full bladder, pain, limb movements, trauma, temperature, light, noise, sleep disorders, acid reflux, depression and anxiety can also be triggers. Clearly, unconscious wakefulness is a major modifiable risk factor for cardiovascular disease and is also a risk factor for all-cause dementia. Isn’t it about time we took this seriously and started a public health campai...

DESIGNECOLOGIST on Unsplash If you snore you should probably make sure you don’t have obstructive sleep apnea (OSA).  In this study below OSA severity was associated with Alzheimer’s disease pathology burden in the hippocampus the region of the brain responsible for memory. These results indicate that OSA may account for some of the “cognitively normal” individuals who have been found to have substantial amyloid burdens, and are currently considered to be at a prodromal stage of AD. The implications of this and other studies linking sleep deprivation to Alzheimer’s disease and dementia are profound and imply that sleep hygiene and preventing sleep disorders may be a strategy to reduce the lifetime risk and incidence of dementia. Sleep is critical for the brain to clear itself of protein debris and if you have insufficient sleep the debris accumulates, for example, amyloid plaques associated with Alzheimer's disease. OSA and other sleep disorders may therefore bring forward the AD ...