Wednesday, September 24, 2014

Insomnia and obstructive sleep apnea

I've followed Dr. Barry Krakow's work for years, starting when I was a fellow at Dartmouth. Dr. Krakow is an expert on insomnia, nightmare treatments, and obstructive sleep apnea (OSA). I have a copy of one of his insomnia books, called Sound Sleep, Sound Mind, and I recommend it highly. Besides treating nightmares, Dr. Krakow has brought to the mainstream the common co-existence of insomnia and OSA, and the relationship to each other. Now, he has published an exciting paper in the Mayo Clinic Proceedings, but I don't have access to it - all I have is the abstract.

In this study, Dr. Krakow evaluated over 1200 patients with chronic insomnia. Almost three-fourths of the insomnia patients did not respond to medications for their insomnia. Dr. Krakow studied 942 of them in the sleep lab using the most modern testing equipment, not done in older insomnia studies. Results showed that over 90% of these patients had moderate to severe OSA! The results are somewhat surprising with respect to the percentage of insomnia patients that had undiagnosed OSA. In my clinic, I regularly get patients referred to me for "insomnia" that actually have OSA, and sometimes it is severe. In these cases, treating the OSA usually improves sleep quality significantly such that sleeping pills are no longer needed.

The bottom line is that patients with chronic insomnia that do not respond to medications may benefit from referral to a sleep specialist for evaluation of underlying medical causes of the insomnia, such as OSA.

Wednesday, September 17, 2014

Brain changes before and after CPAP treatment for obstructive sleep apnea

Some studies have shown changes in the white and gray matter of the brain from untreated obstructive sleep apnea (OSA). The gray matter refers to cell bodies in the brain and is generally on the outer surface. White matter is the connections between the cell bodies and some of the supporting cell types - it's deeper in the brain, meaning below the gray matter.

This study sought to evaluate white matter changes and impact on cognition in patients with OSA, and if the changes were reversible with CPAP therapy. The researchers studied 17 patients with severe OSA and compared them to similar patients that did not have OSA. The treated patients were evaluated at baseline, 3 months, and at 12 months - however, the controls were only evaluated at baseline. CPAP use was monitored objectively with downloads from each unit.

Results showed changes in white matter in the untreated OSA patients. There was only limited improvement with 3 months of CPAP, but there was significant improvement at 12 months of CPAP. This is an exciting study because it suggests that the brain damage inflicted by untreated severe OSA may be reversible with regular, prolonged CPAP treatment.

Wednesday, September 10, 2014

Benefit of CPAP use in older people with obstructive sleep apnea

Here is a study about obstructive sleep apnea (OSA) treatment in elderly people. It was done in the UK over 12 months in those 65 years and older with OSA. Subjects were randomized to get CPAP treatment or no CPAP treatment. Those who did not get CPAP received advice on minimizing daytime sleepiness through sleep habits, napping, caffeine use, and weight loss. The main purpose of the study was to see if CPAP use reduced sleepiness levels and if CPAP is cost-effective.

Results showed that subjective sleepiness was reduced to a greater extent in those that received CPAP treatment. As expected, the reduction in sleepiness levels was greatest for those who started out with the highest sleepiness levels. CPAP use reduced healthcare usage, which offset the cost of the CPAP - the authors concluded that CPAP use is cost effective for older patients.

Other outcomes were measured as well. CPAP use did not improve cognitive function or blood pressure. CPAP did improve total cholesterol levels at 3 months, but not at 21 months. Night time urination, and home and driving accidents were not improved with CPAP use.

What is most interesting to me about this study is that CPAP improved sleepiness despite a low amount of CPAP use by the participants. Good CPAP usage is generally defined as using CPAP at least 4 hours per night on 7 out of 10 nights. In this study, usage was about 2 hours per night on average.

Wednesday, September 3, 2014

American Pediatric Association "Let Them Sleep" statement

The American Pediatric Association recently released a statement that middle and high school students start school at 8:30 AM or later. Sleep-related research supports the later school start time so that adolescents can get more sleep per night. The recommended amount of sleep for teenagers is 8.5 to 9 hours per night, with the majority of teens not getting close to that. Chronic sleep deprivation has been linked with obesity, diabetes, mental health problems, and reduced academic performance.

The statement goes on to explain that teens lack of sleep is complex and involves homework, extracurricular activities, after-school jobs and use of technology that can keep them up late on week nights. So just delaying school start times may not improve teens' sleep duration if other lifestyle changes are not made. The most obvious one is restricting screen time at night.