Wednesday, November 25, 2015

Sleep apnea and Meniere's Disease

Meniere's Disease involves the ear, and produces symptoms of hearing loss, tinnitus (ringing in the ears), and vertigo (a form of dizziness). Nausea and vomiting often accompany the vertigo. Meniere's Disease is usually treated with medications, but that does not always help. Some research has pointed to an association of poor sleep quality and Meniere's Disease. Obstructive sleep apnea (OSA) can result in poor sleep quality and could worsen Menierie's.

This small study looked at the effect of 6 months of CPAP therapy on Meniere's Disease. All 20 patients had failed medication management of Meniere's Disease. All had OSA diagnosed with a sleep study, and all used CPAP therapy only. They did not restart their Meniere's medications during this study. Results showed that CPAP therapy by itself reduced the impact of the vertigo and the low-frequency hearing loss associated with Meniere's disease.

The reason that treating OSA may help Meniere's is unknown. The study authors speculate that elimination of low oxygen levels when asleep may be the factor that improves the Meniere's. I also wonder if elimination of the snoring helps.

Wednesday, November 18, 2015

Pets and sleep

Lots of people sleep with their pets in their bed. This is fine unless it disrupts your sleep. This article discusses research at the Mayo Clinic showing that 18% of pet owners feel their pets disturb their sleep. The article goes on to discuss how you can get your pet out of your bed if it is bothering your sleep.

Wednesday, November 11, 2015

Control of dream sleep

The neurobiology of sleep is complicated - so many pathways in our brains seem to affect sleep and the different sleep stages. For example, the pons, a part of the brainstem, is thought to be the major part of the brain generating dream sleep. This article and abstract summarize elegant research demonstrating that a group of neurons in the medulla, which is below the pons, can generate signals that start dream sleep. The researchers postulate that these medullary neurons project up into the pons. This finding is interesting in that the medulla is responsbile for unconscious processes that regulate heart rate, blood pressure, and breathing, as well as other autonomic features. These research results may bolster the argument that dreams are not from the conscious brain, but more of an automatic process like breathing or heart rate. Unfortunately, these findings don't help us understand the function of dreaming any better than our current understanding.

Wednesday, November 4, 2015

Restless legs syndrome and cardiovascular disease and kidney disease

Restless legs syndrome (RLS) is a chronic neurological condition that causes discomfort in the legs in the evening before sleep. Studies have linked RLS with certain cardiovascular diseases such as high blood pressure. This article is about a study that examined RLS in veterans. Specifically, the researchers studied the relationship between RLS and stroke, heart disease, kidney disease, and mortality rate. The researchers compared about 3700 veterans with and without RLS. Results showed higher amounts of stroke, coronary heart disease, chronic kidney disease, and mortality in those that had RLS compared to those that did not.

The results are not surprising. And as the article points out, the findings don't show that RLS causes strokes, heart disease, or kidney disease. One issue is whether the RLS in these veterans was primary, or secondary to another disorder, such as obstructive sleep apnea (OSA). OSA can significantly worsen RLS, meaning that it may be the OSA that is increasing the incidence of cardiovascular or kidney disease - not necessarily the RLS. Also, RLS is known to be common in patients with chronic kidney disease, especially those on dialysis. More studies are needed to tease out the relationship between RLS and these other disorders.

Wednesday, October 28, 2015

Sleep patterns of traditional societies

Here is an interesting article about a research study that received lots of media attention. The researchers studied the sleeping patterns of three traditional societies in Africa and South America - apparently their lifestyles resemble ancient hunter-gatherers. Results showed that the three groups slept 6 hours and 25 minutes per night on average. The sleep duration was similar between the three groups. Despite getting only 6'25" of sleep per night, the participants did not complain of feeling sleepy in the daytime and very rarely took naps.

A surprising result was that natural light did not affect the timing of sleep, as all three groups fell asleep on average 3.3 hours after sunset - which is the time when the temperature was falling. Even more interesting was that all of the group members woke up when the temperature was at its lowest.

Of note, insomnia was extremely rare - two of the groups did not even have a word for it!

Wednesday, October 14, 2015

Sleep and heart disease

Certain sleep disorders such as obstructive sleep apnea have been linked with cardiovascular disease. This article reviews research about sleep duration and quality and coronary artery disease. I only have access to the article and the abstract. Researchers asked subjects to rate their sleep quality and the amount of sleep they get. The results showed that those who slept 5 or less hours, or 9 or more hours, had increased rates of coronary artery calcification and stiffness - both of which are early signs of coronary artery disease.

As far as I can tell, sleep quality and duration were assessed via questionnaire. There was no sleep study or other objective sleep duration measurement such as actigraphy. So it could be that some of the subjects had poor sleep quality from un-diagnosed obstructive sleep apnea, and that could account for some of the increased rates in coronary artery disease.

Wednesday, September 30, 2015

CPAP use, obstructive sleep apnea, and cardiac function

Studies have shown that obstructive sleep apnea (OSA) can negatively impact cardiac function, especially if the OSA is severe. And studies have shown that treating severe OSA with CPAP can improve cardiac function. However, studies have not shown clearly that treating milder cases of OSA provides significant cardiac benefit.

This study looked at patients with mild-to-moderate OSA with mild cardiac dysfunction. Patients were minimally symptomatic with regards to OSA as well. Patients were either given CPAP for 6 months or given no CPAP. Compliance with CPAP was determined based on the CPAP download. The results did not show any convincing change in cardiac function or structure after 6 months of CPAP usage. There was no dose response effect with CPAP usage either, meaning that there still was no change in cardiac function in those that used CPAP the longest per night.

The researchers concluded that CPAP use in patients with mild OSA and mild cardiac dysfunction may not be as helpful as traditional cardiac dysfunction treatments like blood pressure medications.