Wednesday, March 30, 2011

Sleep Disturbances and PTSD

Review article in Medscape about the sleep disturbances in post-traumatic stress disorder (PTSD). Nightmares are a common feature of PTSD, with a reported prevalence of 50%-90% in long-term epidemiologic follow-up studies. Insomnia (both sleep-onset and maintenance insomnia) is a problem for most patients with PTSD. The reason for the sleep disturbance in PTSD has not been fully worked out. It's thought that underlying depression or anxiety could be a cause. Interestingly, obstructive sleep apnea is more common in PTSD patients. Periodic limb movements in sleep (PLMS) is more common in PTSD patients than in control patients. However, many of the medications used in PTSD could cause PLMS, meaning that it could have nothing to do with the PTSD directly. Treating the sleep disturbances in PTSD can potentially improve the lives of these patients.

Thursday, March 24, 2011

Sleep Deprivation and Appetite

Another article about how sleep-deprived individuals consume more calories. This is from the USA Today about findings in a study reported at the American Heart Association meeting in Atlanta. This study had 26 people who usually slept 7-9 hours per night. They had the patients sleep in a monitored room for six nights. Half of the patients slept 4 hours per night and the other slept for 9 hours per night. I don't know how or why they chose those specific hours. I am also unclear if they used a control sample during this study.

For the first days, they received a portion-controlled diet, but the last two days they could eat as much as they wanted from food they chose themselves. The results showed that patients consumed an average of 296 calories more when they were sleep-deprived compared with when they were well-rested. Overall, most of the extra calories came from high-fat foods such as ice cream and fast foods.

In the USA Today article, the reporters interviewed scientists about the study results. Reasons for overeating include possible hormonal changes that control appetite. This appetite increase, along with being too tired to exercise, could lead to weight gain in sleep-deprived people.

As I have said in other posts, sleep-deprivation does not cause obesity. It could have a contributing role. I understand the interest in these findings - after all, it could mean that overweight patients would only have to sleep a little longer to lose weight. If only it was that easy. In my opinion, weight gain is caused by eating too much and exercising too little.

Monday, March 21, 2011

Sleep Restriction and ADHD

In the March edition of the Sleep Journal, there is an article about the effect of sleep restriction on cognitive performance of children with ADHD. In this study, researchers studied children with and without ADHD. They measured the kids' performance on cognitive testing while getting normal sleep at home and after getting about an hour (average 40.7 minutes) less sleep per night for six straight nights.

The results showed that kids with and without ADHD experienced deterioration of performance on cognitive testing with sleep deprivation. The researchers had the children with ADHD stop their medications 48 hours before the study. It would have been interesting to see if the kids with ADHD were able to improve their cognitive performance on their medications despite sleep restriction.

I think the point of this study is that sleep deprivation could worsen academic performance if kids are sleep-deprived. In our society, many pre-teens are sleep deprived, at least according to the amount that sleep experts say these kids should be getting. If you have a child with ADHD, make sure they get plenty of rest.

Friday, March 18, 2011

Nasal Resistance While Awake and Upper Airway Resistance While Asleep

In the February edition of the Journal of Clinical Sleep Medicine is a study where researchers assessed the ability of non-invasive nasal resistance measurement while awake to predict the amount of upper airway resistance while asleep and on CPAP.

The researchers measured nasal airflow resistance with two different non-invasive techniques. There was no correlation between the two techniques while the subjects were sitting up awake. There was weak correlation between the two techniques while the patietns were awake but lying down on their back.

There was no clear relationship between OSA severity and either subjective reports or objective measurements of nasal airflow resistance while subjects were awake. Airlow resistance in the throat made while subjects slept did not correlate with objective measurements of nasal airflow resistance while awake.

It would be nice to have an objective, non-invasive indicator of throat resistance and/or OSA severity that could be done while the patient is awake in the sleep clinic. Unfortunately, the results from this study do not support measuring nasal airflow resistance for these purposes.

Thursday, March 17, 2011

Nose Flow Resistance and Obstructive Sleep Apnea

There is a study in the Journal of Clinical Sleep Medicine where researchers investigated which patients with OSA would respond to a new treatment device. The treatment is Provent which is a one-way valve worn in the nostrils during sleep. The valve allows you to inhale normally, but makes it difficult to exhale through the nose. This exhalation difficulty increases the pressure inside the upper airway at a time when some patients with OSA are prone to collapse their throat, usually due to decreased airway pressure.

The way Provent works to reduce OSA is not known entirely. It is postulated that the device increases pressure duing expiration, which would make it harder for the airway to collapse. The device might also increase CO2 levels during sleep, which could incresae muscle tone in the airway and make it more difficult to collapse. Finally, the device could increase lung volumes while asleep, which would "tug" on the upper airway and reduce collapsibility.

The researchers studied 20 patients and ten of them demonstrated an objective response during polysmongraphy. Four patients had a partial response and five patients were considered non-responders to Provent. Neither baseline OSA severity nor obesity level predicted who would respond to Provent. However, there was a trend with the resonders if they had more severe OSA on their back than on their sides.

There could be a few reasons why the Provent did not work in all patients. Some were mouth breathers, so a nose device would not help. Also, in some patients with OSA, their airway collapses during inspiration, but not expiration. As this device works only during the expiratory phase of breathing, it would not work in those particular patients.

Monday, March 14, 2011

Bedwetting Children and Sleep Quality at Home

Interesting article in the March edition of the Sleep Journal about bedwetting, which occurs in upto 15% of children and sometimes has no known cause. Parents of children who wet the bed often say that their child sleeps too deeply. But research does not support this when kids with and without bedwetting have sleep studies.

In an attempt to cope with the bedwetting, some parents wake up their child during the night or maneuver them to the potty to prevent accidents in the bed. The authors of this study suggest these awakenings could worsen bed wetting.

They measured the sleep in children with and without bedwetting over five continuous nights at home with a portable sleep monitor (actigraphy). The results showed that kids with bedwetting had more nighttime awakenings and were more tired in the morning. Of all the awakenings, 27% were to prevent bedwetting, 2% were by parent after bedwetting, 20% were by child after bedwetting, and 50% were unrelated to bedwetting.

The authors theorize that if bedwetting kids have more broken up sleep at home, they are more likely to be sleep-deprived. Being more sleep-deprived will make it harder to wake up to empty their bladders. Therefore, reduced sleep quality may play a role in the maintenance of bedwetting.

Thursday, March 10, 2011

Obstructive Sleep Apnea and Neurocognitive Performance

In the March edition of the Sleep Journal is an article featuring a cross-sectional analysis to see if patients with untreated obstructive sleep apnea (OSA) have impairments in attention, learning, memory, and ability to follow through on tasks (referred collectively as neurocognitive function). The patients are from a large study to determine if 6 months of CPAP use improves neurocognitive functioning in OSA patients.

There are studies that show that OSA is associated with neurocognitive deficits. The results from this study, however, show that the associations between OSA severity, objectively determined sleep quality, and sleep duration, and neurocognitive function are weak and inconsistent. When there was neurocognitive impairment, it was associated with severe oxygen desaturations, regardless of OSA severity.

The study authors noted that participants were more educated than the U.S. population, with 15.5 years of education on average. Perhaps because they were more educated, the study participants started out with higher intelligence than the average U.S. population. Apparently, there is evidence that patients with higher intelligence are more resistant to adverse neurocognitive effects from untreated OSA.

The point of all this is that this study did not show that neurocognitive deficits are associated with OSA (regardless of the severity) by itself. The finding that was associated was low oxygen levels (<85%) which can occur in conditions other than OSA like COPD. These results fly in the face of my clinical experience - that patients with broken up sleep from OSA (even without low oxygen levels) have trouble concentrating and don't feel as sharp. After they start CPAP, they can function better.

Sunday, March 6, 2011

The CDC and Adult Americans Sleep Habits

There has been some press about the two reports in the March 4th issue of the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report.

In the first report, 35.3% reported having <7 hours of sleep on average during a 24-hour period. 37.9% reported unintentionally falling asleep during the day at least one day in the prior 30 days, and 4.7% reported nodding off or falling asleep while driving in the preceding 30 days.

In the second report, 37.1% of adults reported regularly sleeping less than seven hours per night. Perceived sleep-related difficulties were more likely among individuals reporting <7 hours of sleep as compared with those reporting 7-9 hours of sleep; the most prevalent was an inability to concentrate on doing things (23.2 percent).

As others have stated, both of these reports suggest that more than one-third of American adults are not getting enough sleep. It would be interesting to know if the the same 35.3% who get <7 hours of sleep were among the same 37.9% who felt sleepy during the day. As sleep needs vary, some people can get by on less than 7 hours. Also, some still feel sleepy with more than 7 hours if their sleep quality is reduced by a medical or sleep disorder.

Thursday, March 3, 2011

Obesity and Inadequate Sleep

At the Annual Meeting of the Associated Professional Sleep Societies, there was a research study that concluded that body mass index (BMI), an indicator of obesity, correlated with self-reported days of insufficient sleep per month.

The researchers studied more than 380,000 U.S. adults via telephone health survey. The asked participants how many of the last 30 days did the person feel like they did not get enough rest or sleep. The number of days of insufficent sleep steadily rose as the BMI increased. Normal weight participants (37% of those studied) reported 7.9 days of insufficient sleep per month. Morbidly obese participants (3.5% of those studied) reported 11.1 days of insufficient sleep per month.

After adjusting for demographic variables, physical activity, and smoking, those with morbid obesity were 1.8 times more likely to have at least 14 days of insufficient sleep in the past 30 days.

A spokeswoman from the CDC said that the implications of this study is that insufficient sleep should be addressed in weight-reduction programs, and excess weight should be considered in developing programs to address sleep disorders. The spokeswoman did not attempt to say that insufficient sleep causes obesity.

I have some issues with this research. One is that it is a telephone survey with no objective data from a clinician or testing. Patients who report that they did not get enough sleep could be getting the right quantity of sleep, but just the wrong quality of sleep. Obstructive sleep apnea, which is associated with obesity can rob people of sleep quality, no matter how much they slept. It is not clear the researchers addressed this comorbidity. Also, the percentage of participants that were morbidly obese was over ten times smaller than those with normal weight, so that could skew the results.

Tuesday, March 1, 2011

Sleep Deprivation, Elective Surgical Procedures, and Informed Consent

There was an article in the December 30th edition of the New England Journal of Medicine about sleep-deprived surgeons. The authors propose that surgeons awake 22-24 hours be required by law to disclose that to patients about to undergo elective surgery so that the patient can reschedule if they want. Apparently, complication risk goes up 83% for elective surgeries when the surgeon has less than a six hour opportunity to sleep between procedures when on call the night before.

Organized medicine, such as the surgery specialty societies are not happy about this proposal. They feel that surgeons should be able to judge for themselves if they are capable of proceeding with an elective surgery. Also, telling a patient that you are "sleep-deprived" could set up a surgeon for a lawsuit. Surgeons fear that next they will be forced to reveal any financial or even marital problems they are having to their patients, because such personal problems could affect operating room performance.

Unfortunately, sleep deprivation decreases your ability to recognize if you are impaired from the sleep loss. Thus, one solution is educating surgeons (and all other medical specialties) how to recognize fatigue and how fatigue degrades cognitive and physical performance.

Already, the FAA restricts pilots from flying if they haven't had a certain number of hours of sleep. And residents (physicians in training) have their work hours limited to improve patient safety and reduce resident health problems.

I am not convinced federal regulation is the answer to sleep deprived surgeons, but I can see both sides of the argument. More data is needed and more education of all involved might a good first step.