Insomnia subtype affects daytime functioning

This article discusses research about insomnia. It follows revision of the mental health classification manual (DSM-V) that emphasizes insomnia as a disorder, rather than as a symptom of another mental, medical, or sleep disorder. Researchers surveyed people with insomnia. Results showed that in those with the most sleep disruption - both onset and maintenance problems, coexisting mental health problems, and if it started in childhood, have the most daytime impact. This makes sense to me and fits what I see in my chronic insomnia patients.

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.

CPAP Use, Sleepiness, Quality of Life, and Daytime Functioning

In the January issue of Sleep, there is an article that studied the effect of three months of CPAP use on daytime sleepiness, daytime mental functioning, and quality of life in patients diagnosed with moderate to severe obstructive sleep apnea (OSA).

The authors explain that excessive daytime sleepiness (EDS) is common in patients with and without OSA. Other causes of EDS are obesity, age, typical sleep duration, diabetes, and smoking. Also, studies have shown that EDS does not improve in every patient with OSA even if they are optimally treated with CPAP.

In this study, the authors performed a maintenance of wakefulness test (MWT) after three months of CPAP use, which measures a patient's ability to stay awake throughout the day. The Federal Aviation Administration uses the MWT results in pilots with OSA to determine if the CPAP is working such that they can fly safely. Interestingly, there was no improvement in the MWT results even in patients who were optimally compliant with CPAP.

The authors measured subjective sleepiness with a common question and answer scale called the ESS. Finally, the measured daytime mental functioning with subjective (question and answer tests) and objective computer testing.

The ESS scale showed improvement with more CPAP use. However, even if the patient used CPAP 7 hours per night, 19% of compliant OSA patients had an elevated ESS, indicating persistent sleepiness.

Daytime mental function levels varied considerably in OSA patients before treatment. There was a predictable improvement in some patients who used CPAP on some of the measures of daytime functioning, but not in everyone, including those who used the CPAP an optimal amount.

The results of this study are consistent with other studies' results and with my clinical experience. Not everyone gets all the way better with regular CPAP use. There are other reasons to use CPAP consistently, though, including cardioascular protection.

Another intersting point brought up by the authors was whether the MWT is the most appropriate measure of a pilot's ability to fly safely with regards to EDS. Perhaps these pilots should have a different daytime sleepiness measure such as the MSLT, which is used to diagnose narcolepsy.