Alzheimer’s disease is the most common form of dementia, which is a set of symptoms that include memory loss and problems with thinking, problem-solving and language. It is a physical disease that affects the brain and proteins build up in the brain forming ‘plaques’ and ‘tangles’ around the nerves. Connection is then lost between the nerves cells and leads to the death of the nerve cells and loss of brain tissue. Patients with Alzheimers also have a shortage of important chemicals that help to transmit signals around the brain. The disease is progressive and as more of the nerve cells die and brain tissue is lost, the more severe the symptoms.
Sleep apnoea is a condition where the walls of the throat relax and narrow during sleep and interrupts normal breathing patterns. During an episode the lack of oxygen triggers your brain to pull you out of your deep sleep so that your airway reopens and you can breathe normally. After falling back into a deep sleep again further episodes can occur even as frequently as every few minutes. Most patients snore loudly and have laboured and noisy breathing and is often interrupted by gasping and snorting. This repeated sleep interruption can make patients feel extremely tired during the day and suffer from reduced mental ability. However unless a partner or family member notices your symptoms whilst you sleep you may not know that you suffer from this condition and many people go undiagnosed.
Recent studies have shown that sleep apnoea may quicken memory decline and bring forward the onset of memory impairment conditions like Alzheimers by 10 years. The development and progression of Alzheimers may also be speeded up by sleep apnoea as well. These studies also revealed however that sleep apnoea patients that were being treated with supplemental oxygen overnight delayed the onset of memory impairment problems by as much as 10 years. Patients with sleep apnoea who were being treated declined at the same rate as volunteers who did not have sleep apnoea showing that being treated by oxygen counteracted the harm being done by the condition. It appears that the frequent drops in oxygen levels during episodes of untreated sleep apnoea have a major impact upon memory impairment and can directly lead to the early development of Alzheimer’s and dementia. Also during sleep is when the brain has time to remove harmful waste products, if sleep is disturbed then there is an accumulation of harmful proteins that block nerve cell function. Certain parts of the brain are more sensitive to drops in oxygen levels than others; certain neurons in the hippocampus (where Alzheimer’s is thought to start) is especially sensitive to drops in oxygen and sleep apnoea may ‘stress’ these neurons out.
There are currently no medications that can prevent the progression of mild cognitive impairment to Alzheimer’s disease or dementia so treating at-risk patients with CPAP (oxygen treatment for sleep apnoea) is a prevention method that is worth trialling and testing. Previous research has already shown that CPAP treatment and supplemental oxygen at night slows and improves cognitive impairment in patients with Alzheimer’s disease and increases brain tissue and now this more recent research backs up these findings. Hopefully soon there will be trials to prove whether supplemental oxygen at night could be the next new treatment for Alzheimer’s and dementia patients or even those who are at risk.