MS Research Roundup: How Sleep Problems Can Link to Fatigue
Often, people with chronic illness research symptoms, medications, or other aspects of their conditions on the Internet as a way to take ownership over their health. However, breaking down research studies can feel like leaping blind into the wilderness. In this occasional mini-series, I break down research related to sleep, fatigue, and MS. Take a walk with me; maybe I can help you better navigate the intricacies of research papers so you can better understand the latest research into MS. –Tamara Sellman, RPSGT CCSH
“Sleep disturbance and fatigue in persons with multiple sclerosis (PwMS): a meta-analysis.”
Fatigue is considered the number one symptom of MS. When we are sluggish, tired, sleepy, and listless during the day, it can make leading a normal life really tough.
For many, the daytime fatigue is so tough it means leaving behind a well-earned career, or falling behind on basic activities of daily living, or losing touch with friends and family because it can be simply too hard to maintain social ties.
How might sleep problems factor into your daytime fatigue?
Let’s take a closer look at “Sleep disturbance and fatigue in persons with multiple sclerosis (pwms): a meta-analysis.”
“The objective of the present study was to systematically and quantitatively investigate the association between sleep disturbance and fatigue in PwMS, with a focus on how this association differs between sleep parameters.”
What does this mean?
Researchers (in this case, Bhattarai, et al) wanted to look more closely at links between sleep problems, daytime fatigue problems, and multiple sclerosis. They chose to look at these links by measuring different kinds of sleep problems.
Bhattarai, et al conducted a comprehensive literature search in five electronic databases, arriving at 37 studies that:
- “Included at least one measure of fatigue and at least one measure of sleep”; and
- “Provided sufficient data to obtain bivariate correlations, odds ratios, and/or standardized mean differences for the relationship between sleep and fatigue.”
Also: “Separate analyses were conducted based on the sleep parameters assessed and whether the measures were subjective (patient-reported) or objective (PSG, actigraphy).”
What does that mean?
They are showing how they drilled down inside the data they collected to arrive at their results.
Measures of fatigue or sleep refers to the data they found, isolated, and examined in those 37 studies.
The studies they chose clearly identified relationships between sleep and fatigue, making it easier for them to compare apples to apples.
Finally, they took study data and compared it subjectively versus objectively.
Patient self-report is essentially a subjective report of sleep problems that a patient shares with the researcher. Subjective reports are not considered wholly scientific and may be a bit biased or inaccurate. Nonetheless, subjective self-reporting is considered a useful tool in research.
These objective measures of sleep problems include the raw data collected when a sleep study was performed, as well as data collected from a wrist-worn device known as an actigraph. This information is considered factual because it can be measured scientifically.
From Bhattarai, et al:
“Mean effect sizes (r) for associations between sleep parameters and fatigue were: moderate for objective REMSOL (0.42*), subjective insomnia (0.36*), objective sleep-related movement (0.34*), and objective sleep-disordered breathing (0.28); and weak for subjective sleep-disordered breathing (0.22*), objective nocturnal arousals (0.22*), sleep efficiency (0.17*), sleep onset latency (0.15*), and sleep duration (0.13). *p<.05.”
What does this mean?
It can be confusing to understand the numeric values of research!
Let’s take a look at this particular analysis by breaking down findings by what they measured.
There was a moderate (not strong or weak) link between poor sleep and fatigue when they looked at the following:
Subjective data on insomnia
For those people with MS who complained of sleeplessness, a moderate link to daytime fatigue was found. It wasn’t “in their heads” …they really didn’t sleep well and it resulted in being tired during the day.
Objective data on REM sleep onset latency, sleep-related movements, and sleep-disordered breathing
- REM sleep onset latency (REMSOL) measures the time between falling asleep and having a first stage of REM (rapid-eye movement) sleep (which normally happens up to 90 minutes after falling asleep). In this analysis, they found a moderate link between this and daytime fatigue.
- Sleep-related movements describe periodic movements of the limbs that happen after you fall asleep. Most people are unaware they even have these, but they can be a huge disrupter of sleep. While common in the general population, they’re possibly even more common in people with MS.
- Sleep-disordered breathing refers to snoring, upper airway resistance, and or sleep apnea. Sleep-disordered breathing is commonly viewed as a mechanical problem, but it can also occur neurologically. This makes it a concern for people with MS.
Meanwhile, a weak (not strong or moderate) link between poor sleep and fatigue was uncovered with:
Subjective sleep-disordered breathing
If the patients complained of having problems breathing while sleeping, it did not seem to be linked to their daytime fatigue. This is interesting because when sleep breathing was measured objectively by sleep studies in this analysis, it was found to show a moderate linkage to daytime fatigue.
Objective nocturnal arousals
- These are all those times you wake up at night, caught and recorded by scientific measures. The study implies that measures of nighttime awakenings didn’t seem to have an effect on daytime fatigue.
- Sleep efficiency, sleep onset latency, and sleep duration
- These are also objective measures captured in an overnight sleep study, and represent details of a typical night’s sleep for the patient. According to Bhattarai, et al, these measures were poorly linked to daytime fatigue.
From Bhattarai, et al:
“For PwMS, sleep disturbances stemming from abnormal sleep staging, neurologic symptoms, and perceptions of poor sleep were the strongest predictors of fatigue.”
The study authors also suggested that “interventions focused on identifying and treating co-morbid sleep disorders (e.g., narcolepsy, restless legs, sleep apnea) and problematic sleep behaviors may offer more promise in improving fatigue in MS than those focused on extending sleep duration or increasing sleep efficiency.”
What does this mean?
Basically, their data review and analysis suggests that people with MS are most likely to experience daytime fatigue related to:
- Problems with their sleep architecture (the various stages of sleep they achieve, and how many),
- Their neurological symptoms (spasticity, disruption of the parts of the brain that contribute to the sleep process), and
- Perceptions of poor sleep
Perceptions of poor sleep is an interesting phenomenon. Generally speaking, people cannot be certain about how much sleep they actually get (because they’re asleep, after all!) and often underestimate how many winks they get in a given night. (As a sleep technologist, I’ve frequently seen this unfold in sleep studies.)
What Bhattarai, et al is suggesting here is that patients who believe they did not get enough sleep (a subjective opinion) are potentially more likely to feel tired during the day. However, objective data doesn’t seem to support this.
I know that if I feel like I sleep poorly one night, I feel tired during the next day, even if an objective test measures otherwise. Sometimes we must face our relationship with the power of suggestion…
Bhattarai, et al encourages more investigation into the sleep problems of people with MS. Our daytime fatigue may not necessarily relate to how much sleep or the quality of the sleep we have. It’s possible that we may also have a separate sleep disorder that needs diagnosis and treatment.
What you should take away from this research
If you have problems with daytime fatigue, it might be worthwhile to undergo a sleep study.
This can happen either:
- Overnight in the lab, where a large amount of data is collected, or
- At home, using wristband actigraphy or a home sleep apnea test in conjunction with a pulse oximeter
You need a referral to undergo a sleep test. If you explain your sleep and fatigue concerns to your neurologist or primary care physician, they can help you decide your next course of action.
Identifying and treating a hidden sleep disorder may not cure your MS, but ultimately, it could help you reclaim your daytime energy and feel better.
See the original paper here: https://academic.oup.com/sleep/article/41/suppl_1/A377/4988060
- Bhattarai J, Dunn KM, Hughes AJ. SLEEP, 27 Apr 2018;41:Issue suppl_1, p. A377. https://doi.org/10.1093/sleep/zsy061.1015. Disclosures: J Bhattarai’s research is funded by the National Multiple Sclerosis Society Mentor-Based Fellowship #0032. AJ Hughes’s research is funded by the National Institutes of Health #K23HD086154.