Obstructive sleep apnea and multiple sclerosis

Multiple sclerosis (MS) is a neurological disease thought to be an autoimmune disorder. It causes a variety of symptoms, with a common one being fatigue. Obstructive sleep apnea (OSA) also can cause fatigue. This study sought to examine the relationship between fatigue, MS, and OSA. It was performed at University of Michigan's Neurology Department. MS patients were surveyed about OSA and fatigue. Results showed that 1 out of 5 MS patients reported a diagnosis of OSA. This is higher in the general population. Also, the researchers found that an even higher proportion of MS patients were at risk for having OSA based on a commonly administered questionnaire (the STOP-Bang). Finally, OSA was a predictor of fatigue after adjusting for other clinical and sleep related predictors of fatigue.

What the results mean is that neurologists and other physicians who care for patients with MS should not use the MS as the only reason for a patient's persistent fatigue. OSA could be contributing and the patient may benefit from a sleep evaluation. OSA is treatable and some of the fatigue may improve with OSA therapy.

L-Carnitine and narcolepsy

Narcolepsy is a sleep disorder that causes excess sleepiness. Recently, a study has shown that narcolepsy may be associated with low levels of a compound called carnitine, which is involved in fatty acid metabolism. This study looked at the effects of supplementing L-carnitine in 28 patients with narcolepsy. The study was a randomized, double-blinded, cross-over, and placebo-controlled design that lasted 16 weeks. The participants took 340 mg of L-carnitine in the morning and 170 mg of L-carnitine in the evening. The participants were allowed to take traditional medications for narcolepsy. The primary outcome measure was the patient's subjective assessment of their sleepiness, which was based on the total time the person reported they dozed off during the daytime as recorded in their sleep logs. Of note, there was no objective measurement of sleepiness, such a multiple sleep latency test.

Results showed a statistically significant reduction in subjective dozing time when participants took L-carnitine. Specifically, participants dozed for 49 +/- 34 minutes / day on L-carnitine versus 58 +/- minutes per day on placebo. This may be statistically significant, but I wonder how clinically significant it is. Researchers reported no side effects to the L-carnitine.

The researchers also noted that low carnitine levels may be seen in chronic fatigue syndrome, and that it's been reported that L-carnitine supplementation resulted in significant improvement in fatigue severity after two months of use.

The effects of sleep deprivation on facial appearance

This article received lots of press. Researchers took photographs of subjects after 8 hours of normal sleep and after 31 hours of sleep deprivation following only 5 hours of sleep the night before. The researchers then asked volunteers to list facial cues they associate with looking fatigued. The final list consisted of hanging eyelids, red eyes, swollen eyes, glazed eyes, dark circles under the eyes, pale skin, wrinkles around the eyes, rash / eczema, and droopy mouth corners. Finally, the researchers had participants rate the photographs for the fatigue cues.

The results showed that the fatigue cues were significantly found in the photographs of sleep deprived subjects - no big surprise. With the exception of glazed eyes, all of the cues that correlated with looking fatigued were also affected by sleep deprivation.

This research is interesting in that these cues for fatigue may help others determine if someone is too fatigued to be safe at work or while driving.

Sleep not to blame for all fatigue

Many of my patients feel that fatigue is due to how long they sleep. In some cases it can be. But fatigue has many causes. This article discusses research showing no link between self reported sleep duration and fatigue. Unfortunately, certain sleep disorders may be occurring without the persons awareness, like obstructive sleep apnea (OSA). OSA can cause fatigue, and treatment of OSA can help. So before concluding that your fatigue is not related to your sleep quality, talk to your doctor.

Comparing sleep between fibromyalgia and rheumatoid arthritis

Both fibromyalgia (FMS) and rheumatoid arthritis (RA) are chronic pain conditions, can disrupt sleep, and result in subjective daytime sleepiness and fatigue. This article discusses a comparison between the two conditions with regard to objective sleep quality at night and daytime sleepiness in women. Researchers did standard sleep studies and surveyed the patients for their subjective experiences.

The results showed that there was similar nighttime sleep disturbance between those with FMS and RA. The FMS patients reported greater subjective daytime sleepiness and fatigue than those with RA. But the sleep studies showed relatively low daytime sleepiness in FMS and an intermediate amount in the RA patients.

These results support clinical findings - that FMS patients are generally not sleepy, but very fatigued. Fatigue can not be measured like sleepiness. Patients with RA are more sleepy, and this is supported with objective testing. RA patients are also fatigued. The authors of the study concluded that FMS patients have less sleepiness and more fatigue due to hyperarousal. This could be true, but unfortunately it is difficult to treat.

Exercise training improves daytime functioning in sleep apnea patients

Exercise may improve obstructive sleep apnea (OSA) severity, even in the absence of weight loss. The less severe the OSA, the better patients may feel in the daytime. This article in the August edition of the Journal of Clinical Sleep Medicine is about a study done to see if exercise training can improve daytime functioning even without reducing OSA severity.

In the study, they had a group of people do supervised exercise for 12 weeks versus the control group that did only stretching for 12 weeks. The two groups of participants were similar with the exception of their baseline sleepiness scores, with the exercise group reporting a little more sleepiness than the stretching group.

The results of the study showed that at the end of the 12 weeks, the OSA severity was 25% lower in the exercise group. The exercise group also had less depressive symptoms, less fatigue, and more vigor than the stretching group. Exercise training caused a lowering if subjective sleepiness, but this was not statistically significant. Exercise training improved physical functioning, vitality, and mental health as measured by questionnaires. Interestingly, there was no difference in participants performance on tests of cognition with exercise versus stretching.

Now you may say that the improvements in exercise were due to OSA severity reduction, not because of the exercise itself as the authors proposed. But, only improvement in fatigue was linked to reduction in OSA severity in the exercise group. All of the other improvements occurred in the exercise group even when the OSA severity remained the same.

These findings are exciting, because not everyone feels better on CPAP. Perhaps exercise may improve their functioning, even though they still have OSA.

Better Sleep and Daytime Functioning When Parents Set Bedtimes in Adolescents

There is an interesting article in the June edition of the Sleep Journal about parents setting bedtimes for adolescents, and the impact this can have on sleep and daytime functioning. Many adolescents are sleep-deprived these days due to early school start times, need to complete homework, after school activities like work and sports, and of course, smart phones / TV / video games in the bedroom.

Researchers surveyed 385 adolescents aged 13-18 years old, and 17.5% of them said their parents set their bedtime. Naturally, this was an age dependent finding, with more younger children reporting parent-set bedtimes than older children. But the interesting part was that those children that had parent-set bedtimes went to bed 23 minutes earlier, slept 19 minutes more on school nights, reported less datyime fatigue, and had less trouble staying awake during the day. There was no difference in the reported time it took to fall asleep, whether the parent or adolescent set the bedtime.

The researchers concluded that the findings from this study support the potential benefit of parent limit-setting around bedtimes for adolescents. Of note, the differences in sleep parameters disappeared on the weekends, when parents did not set bedtimes for the adolescents. This further strengthens the positive effect that the parent-set bedtimes had on sleep.

FAA and Air Traffic Controller Fatige

I saw in the LA Times that the FAA has announced new rules to prevent air traffic controllers from falling asleep on the job. Currently, air traffic controllers caught sleeping on the job, even if on break, can be fired because the agency says that the controllers need to be available for recall at all times. Since April, the FAA said there has been 7 instances of controllers sleeping on the job and 2 others where the controllers did not respond to attempts to contact them.

So the FAA's new plan is that controllers who are sleepy can listen to the radio or read to stay alert during overnight shifts when air traffic is light. The ruling still does not allow the controllers to take naps, even though that would be the most effective way to improve alertness. This makes no sense - if I'm sleepy, reading is probably not going to keep me alert. Physical exercise, napping, and perhaps some caffeine might, but not the radio or reading. I wonder if the American Academy of Sleep Medicine will get involved in this, to help guide the FAA in their attempts to combat controller fatigue.

CPAP, Fatigue, and Sleepiness

An article getting some press is in the January edition of the Sleep Journal. In it, the authors discuss how people use the terms sleepiness and fatigue as if they were the same thing - but they are not. In patients with obstructive sleep apnea (OSA), patients sometimes complain more of fatigue, tiredness, and lack of energy rather than sleepiness. CPAP has been shown to reduce subjective (patient-perceived) and objective (measurable) sleepiness, but has not been shown conclusively to reduce fatigue.

The authors investigated the levels of fatigue, energy/vigor, and sleepiness before and after a three week trial of CPAP in OSA patients. They compared using therapeutic CPAP to fake (sham) CPAP. A total of 59 patients were studied.

The results showed that therapeutic CPAP significantly reduced fatigue and sleepiness, and increased energy/vigor levels compared to sham CPAP. Of note, CPAP was only able to reduce sleepiness in those patients who had a high degree of sleepiness before CPAP. This makes sense and is consistent with what I see in my practice. The authors theorize that fatigue might improve with CPAP because it reduces inflammation that can be seen in untreated OSA.

One reason this study is important is because of the effects on fatigue and energy/vigor levels. This is a common complaint in patients with OSA and is not measured regularly by us sleep physicians. Perhaps it is time we did include a fatigue measure the same way we always ask about sleepiness.