The links between sleep disorders and MS

As a sleep researcher at Neuroscience Research Australia (NeuRA), Dr Hanna Hensen knows about the importance of getting a good night sleep as well as anyone. Ironically, the nature of her work means that she often doesn’t get one herself.

Hensen is researching sleep disorders in people with Multiple Sclerosis (MS), in the hope of finding out how it influences fatigue, cognitive functioning, depression, and falls risk in patients. She is also studying the physiology of MS patients with sleep apnoea.

One of her jobs is monitoring study participants throughout the night at the NeuRA Sleep and Breathing Laboratory near Prince of Wales Hospital in Sydney’s Eastern Suburbs.

Inside the Sleep and Breathing Laboratory
Inside the lab, patients sleep the night in what resembles luxury hotel suites — but they aren’t on holiday. This is the sleep lab where Dr Hensen carries out her polysomnography — the gold standard test to detect sleep apnoea.

To determine if a patient has sleep apnoea, patients are sent to bed strung up with complex electronic instruments. Electrodes on the patients’ heads monitor their sleep patterns, while cannulas in their nose measure oxygen flow. Two bands around each patient’s torso measure the expansion of the chest and abdomen, while another set of electrodes on their legs measure muscle movements that could indicate restless leg syndrome.

Readings from the equipment feed into a control room where Hensen analyses the data.

Why study sleep disorders and MS?
MS is an autoimmune and neurodegenerative disease that affects the central nervous system. One of the intrinsic symptoms of MS — fatigue — affects approximately 70 per cent of cases.

Sleep disorders like sleep apnoea, insomnia, and sleep disruptions such as restless leg syndrome, are also common in MS. But it’s currently unknown how much of the fatigue MS patients experience can be attributed to the action of the disease on the central nervous system and how much to lack of sleep. “Research shows that sleeping disorders are under diagnosed in MS. A lot of patients probably have them and aren’t being treated for them,” says Hensen.

Hensen’s hope is that the findings of her research will contribute to a greater awareness of how sleeping disorders cause symptoms like fatigue, and lead to better diagnosis and treatment options for MS sufferers. “Sleep is modifiable, so treating sleeping disorders could be very beneficial in alleviating symptoms like fatigue in MS suffers,” she says.

Research into MS and risk of falling
Hensen is conducting a sub-study as part of a larger clinical trial. The larger trial — known as the I-FIMS trial — aims to see if it is possible to improve the balance and cognitive functioning, and reduce the risk of falling in people with MS by having them participate in regular step mat training.

The sub-study involves a number of questionnaires, and a device similar to an activity tracker, to measure the role sleep plays before and after the step mat training in 100 participants.

“We know that not sleeping for 17 hours makes your work performance similar to having a blood alcohol reading of 0.05. It could also be the case that a disrupted night sleep influences the risk of falling. That’s something that there isn’t a great deal of research on yet.”

Her findings so far
According to Hensen, two-thirds of the MS patients in the sub-study experienced poor sleep. Sleep apnoea was found in approximately 30 per cent of participants.

Additionally, approximately half the participants in the sub-study were found to have more than one sleeping disorder, such as restless leg syndrome, insomnia, or sleep apnoea — but only a very small number had been diagnosed or treated for these conditions.

She also found a relationship between poor sleep and depression, but it’s currently unknown if one causes the other.

Physiology study in MS patients
A second study by Hensen that looks at the physiology of patients with MS and how sleep apnoea could play an important role in determining how MS patients are treated for sleep apnoea.

In this study, she is comparing people who have sleep apnoea and MS to people who have sleep apnoea only, and trying to determine if certain anatomical features cause sleep apnoea in people with MS.

Anatomical features like a backward-facing jaw or a short neck are known to cause sleep apnoea in the general population. However, sleep apnoea is often seen in MS patients without these features, and in patients without other common risk factors for sleep apnoea like being older, being obese, or being male.

The NeuRA researchers suspect that an underlying mechanism of the disease on the central nervous system could be at work in causing sleep apnoea in MS patients.

“If we are correct, and the disease — rather than the anatomy of MS patients — is causing the sleep apnoea, this information might lead us to develop alternative treatments to those common treatments used to treat sleep apnoea in the general population,” says Hensen. “This study is just in its preliminary stages so there is a lot more work to be done.”

Do you any experiences with sleep apnoea?

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