Sleep apnea and its ability to cause brain damage

Sleep apnea is a sleep disorder where a person experiences interruptions in their breathing while they sleep. Anyone can be affected by sleep apnea, even children. The disruptions caused by sleep apnea are recurrent and can sometimes happen hundreds of times a night if left untreated. These disturbances in breathing can mean that the brain and body do not get enough oxygen to function healthily.

The most common type of sleep apnea is obstructive sleep apnea (OSA). OSA is a result of a blocked airway. Most often, the collapse of soft tissue at the back of the throat is what causes the obstruction.

The other type is called central sleep apnea. It differs from OSA in that it is not the result of a blocked airway. Central sleep apnea is when the brain neglects to send a cue to the muscles to breathe. The failure to address this signal stems from a lack of stability in the respiratory control centre of the brain.

People with sleep apnea are at risk of memory loss and other problems due to changes in the brain’s structure. Brain damage in people suffering from sleep apnea arises as a result of low blood oxygen levels and sleep disturbances.

When apnea occurs, the lungs do not receive oxygen, and the heartbeat gradually slows down. Then the person breathes again. The lungs are able to transfer oxygen into the blood and the heart pumps wildly to get it to all the cells. Within a short time, another apnea takes place and the heart begins to slow down once again. When finally another breath is drawn, the heart begins its frantic beating yet again and the cycle continues.

Oxygen is just as vital for proper brain functioning as it is for other organs. Without oxygen, brains cells will die or at the very least be damaged. Brain damage caused by the trauma inflicted on the brain due to brain cells being destroyed or deteriorating can arise in response to sleep apnea. The pattern of abrupt deprivation and then a sudden flood of oxygen is hard for the organs of the body, including the brain, to handle, resulting in cell damage.

woman sleeping on bed under blankets

Photo by Gregory Pappas

Memory Loss

People with sleep apnea often suffer from forgetfulness, caused by their brains having trouble converting short-term memories into long-term memories.

The research of many scientists, including that of Dr Seung Bong Hong, has also found that people with sleep apnea have on average twenty percent smaller mammillary bodies than regular sleepers. The mammillary bodies are a part of the brain where memory storage takes place, and this can further explain the struggles that people with sleep apnea can encounter when it comes to memory. Reducing the mammillary bodies is an easy to see the manifestation of brain damage in sleep apnea sufferers.

Learning new information takes place in three stages: acquisition, consolidation and recall. Acquisition and recall, the first and last of the three stages only take place while we are awake. While consolidation, the bridging step, can just happen during REM (rapid eye movement) sleep. The REM phase of a sleep cycle is when the brain strengthens neural pathways and clears out redundant information.

Stored experiences accessed at a later point in time play a significant role in how we, as humans interact with the world in day to day life. This is where the trouble of sleep apnea comes in. Although it can occur during any of the sleep phases, it is commonly at its worst during REM sleep. Some individuals find that they only experience sleep apnea during REM sleep due to the naturally reduced muscle tone in the upper airway. With its tendency to disturb sleep, REM cycles are disrupted, even if the individual is not roused. Due to this, the memory consolidation phase can be interfered with, thus preventing the conversion of short-term memory into long-term memory.

Gray and White Matter

Our brains consist of grey matter and white matter.

Grey matter is the darker tissue of the brain and spinal cord. Most information processing occurs in the cerebral cortex, which is what is referred to most of the time when the grey matter is mentioned. Brains cells connected with vital functions such as memory, movement, speech, emotions, self-control and decision making are what makeup grey matter. The functions of processing and cognition are mainly associated with grey matter.

In the simplest terms, white matter is referred to as the messaging system of the brain. Acting as a relay between grey matter in different areas of the brain, white matter coordinates communication between brain regions. White matter plays an active role in affecting how the brain learns and how it functions.

Chronic fatigue, a common effect of sleep apnea, can cause physical brain damage that is obvious enough to be measured.

Multiple studies have shown a decrease in grey as well as white matter in people suffering from OSA (obstructive sleep apnea). Sleep apnea caused structural changes to white matter, particularly to areas that control memory, mood and blood pressure as was found in a UCLA study in 2008. It also discovered notable damage in the brain’s fibre pathways. A survey conducted by O’Donoghue found that on top of that, sleep apnea also causes inflammation in the hippocampus part of the brain.

All of this information further supports the fact that it is vital to diagnose sleep apnea as soon as possible. That way treatment can be started to prevent further brain damage and restore the brain to its original state. When something can quite literally change the shape of the mind it is important to stop it in its tracks and begin restoration immediately, lest it continues to impact daily life.

Blood-Brain Barrier

The blood-brain barrier is a semipermeable membrane. Acting as a filter, it carries to the brain and spinal cord. Its role is to protect the brain from dangerous substances such as harmful bacteria, chemicals and potential neurotoxins to prevent infections. It does this by denying them passage into the brain into the brain.

Sleep apnea increases the blood-brain barrier’s permeability, allowing damaged substances to enter the brain. These substances have the potential to harm and can even lead to epilepsy, stroke, Alzheimer’s disease, multiple sclerosis and other ailments.

OSA sufferers have poor brain blood flow showing weakness in blood regulation in their brains, as described in a study by Paul Macey published in the Journal of Sleep Research. The hypoxia caused by the OSA heightens the threat that a compromised blood-brain barrier and irregular oxygen delivery poses to the brain.

It has been discovered that hypoxia sets off irreparable atrophy, along with cell death and inflammation in the brain. Neural changes that arise due to OSA probably also play a part in central system dysfunction, physiological problems and psychological conditions.

Hope for change

While the effects and dangers of sleep apnea can be overwhelming, CPAP therapy can reverse damage to the white and grey matter parts of the brain.

A study by Castronovo found that after three months of treatment there was some improvement in damaged white matter. However, after twelve months of CPAP therapy, the damaged white material was almost completely healed. As a result of this turnabout, there was a notable change for the better when it came to performance in cognition, mood and alertness.

When it comes to the improvement in grey matter, CPAP treatment produced results after three months. The procedure was able to reduce inflammation in the hippocampus leading to a great boost in emotional functioning. The significant improvements in mood and depressive symptoms were a result of the decrease in inflammation in the hippocampus, as this is the structure that regulates mood.

The most critical function of CPAP therapy is to get the body and brain functioning healthily again. Sleep apnea can be dangerous if left untreated. The good news is that the incurred brain damage and other symptoms are reversible if you take appropriate action.

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