Head Position During Sleep: Potential Implications for Patients with Neurodegenerative Disease
The characterization of sleep in those with neurodegenerative disease (NDD) is essential in understanding the potential neurobiological mechanisms that underlie the connection between sleep disruption and NDD manifestations and progression. Explore the ...
ncbi.nlm.nih.gov
Abstract
Background: The characterization of sleep in those with neurodegenerative disease (NDD) is essential in understanding the potential neurobiological mechanisms that underlie the connection between sleep disruption and NDD manifestations and progression.Objective: Explore the inter-relationships between NDD and age, sex, diagnosis of obstructive sleep apnea, snoring, and duration of sleep time with the head in the supine and non-supine positions.
Methods: A case-control design was used to evaluate differences in sleep position obtained from multi-night, in-home Sleep Profiler recordings in 45 patients with diagnosed NDD (24 with mild cognitive impairment, 15 with Alzheimer’s disease, and 6 with Lewy Body, Parkinson’s, or other dementias) and 120 age-sex matched controls with normal cognition (NC).
Results: The frequency of supine sleep >2 h/night was significantly greater in the NDD than in the NC group (p < 0.001, odds ratio = 3.7), and remained significant after controlling for age, sex, snoring, and obstructive sleep apnea diagnosis (p = 0.01). There were no group differences in nocturnal mobility i.e., number of head position changes/h.
Conclusion: This study demonstrates the utility of in-home measurements of sleep in defining the association of supine sleep position with neurodegenerative disorders. Our findings warrant further investigation, particularly in light of the recent evidence suggesting that sleep may an active role in the brain’s ability to clear CNS neurotoxins and metabolites.
"We compared the in-home sleep patterns of patients with memory impairment resulting from neurodegenerative diseases to a large group of elderly with normal cognition," stated Daniel J. Levendowski, the study's first author and President of Advanced Brain Monitoring. "Sleeping more than 2 hours with one's head lying face upward (i.e., supine) was a significant nocturnal marker that characterized those with memory impairment, after controlling for factors such as age, sex, snoring, obstructive sleep apnea, and movements during the night."Sleeping on Back Linked to Memory Impairment [AlzWeek.com]
SLEEP: Could sleeping on your back hurt memory and increase your brain's risk of developing neurodegenerative disease? CARLSBAD, Calif.--(BUSINESSwww.alzheimersweekly.com
These results corroborate in humans a finding observed in rats by researchers at Stony Brook University and published in the Journal of Neuroscience. Using dynamic contrast MRI, they found that the clearance of neurotoxic proteins from the brain by glymphatic transport was less efficient when the rats' heads were in the supine sleep position. "Our results clearly support their conclusions," added Dr. Philip Westbrook, Chief Medical Officer of Advanced Brain Monitoring. "We also suggest how the interaction between supine sleep and the natural changes that come with age could impact the clearance of β-amyloid, tau, alpha-synuclein, and other neurotoxins from the brain during sleep."
Because imaging of the glymphatic system in humans is not yet possible, additional research is needed to establish a causal relationship between neurodegenerative disease and supine sleep. "The strength of the association, however, points to a potentially modifiable risk factor for neurodegenerative disease, similar to diet and exercise," suggested Dr. Charlene Gamaldo, a co-author and Associate Professor of Neurology at Johns Hopkins University School of Medicine.
The Effect of Body Posture on Brain Glymphatic Transport
The glymphatic pathway expedites clearance of waste, including soluble amyloid β (Aβ) from the brain. Transport through this pathway is controlled by the brain's arousal level because, during sleep or anesthesia, the brain's interstitial ...
www.ncbi.nlm.nih.gov
Abstract
The glymphatic pathway expedites clearance of waste, including soluble amyloid β (Aβ) from the brain. Transport through this pathway is controlled by the brain's arousal level because, during sleep or anesthesia, the brain's interstitial space volume expands (compared with wakefulness), resulting in faster waste removal. Humans, as well as animals, exhibit different body postures during sleep, which may also affect waste removal. Therefore, not only the level of consciousness, but also body posture, might affect CSF-interstitial fluid (ISF) exchange efficiency. We used dynamic-contrast-enhanced MRI and kinetic modeling to quantify CSF-ISF exchange rates in anesthetized rodents' brains in supine, prone, or lateral positions. To validate the MRI data and to assess specifically the influence of body posture on clearance of Aβ, we used fluorescence microscopy and radioactive tracers, respectively. The analysis showed that glymphatic transport was most efficient in the lateral position compared with the supine or prone positions. In the prone position, in which the rat's head was in the most upright position (mimicking posture during the awake state), transport was characterized by "retention" of the tracer, slower clearance, and more CSF efflux along larger caliber cervical vessels. The optical imaging and radiotracer studies confirmed that glymphatic transport and Aβ clearance were superior in the lateral and supine positions. We propose that the most popular sleep posture (lateral) has evolved to optimize waste removal during sleep and that posture must be considered in diagnostic imaging procedures developed in the future to assess CSF-ISF transport in humans.Significance statement: The rodent brain removes waste better during sleep or anesthesia compared with the awake state. Animals exhibit different body posture during the awake and sleep states, which might affect the brain's waste removal efficiency. We investigated the influence of body posture on brainwide transport of inert tracers of anesthetized rodents. The major finding of our study was that waste, including Aβ, removal was most efficient in the lateral position (compared with the prone position), which mimics the natural resting/sleeping position of rodents. Although our finding awaits testing in humans, we speculate that the lateral position during sleep has advantage with regard to the removal of waste products including Aβ, because clinical studies have shown that sleep drives Aβ clearance from the brain.
Sleeping in the lateral, or side position, as compared to sleeping on one's back or stomach, may more effectively remove brain waste and prove to be an important practice to help reduce the chances of developing Alzheimer's, Parkinson's and other neurological diseases, according to researchers at Stony Brook University.Could body posture during sleep affect how your brain clears waste?
Sleeping in the side position, as compared to on one’s back or stomach, may more effectively remove brain waste and prove to be an important practice to help reduce the chances of developing Alzheimer’s and other neurological diseases, new research suggests.www.sciencedaily.com
By using dynamic contrast magnetic resonance imaging (MRI) to image the brain's glymphatic pathway, a complex system that clears wastes and other harmful chemical solutes from the brain, Stony Brook University researchers Hedok Lee, PhD, Helene Benveniste, MD, PhD, and colleagues, discovered that a lateral sleeping position is the best position to most efficiently remove waste from the brain. In humans and many animals the lateral sleeping position is the most common one. The buildup of brain waste chemicals may contribute to the development of Alzheimer's disease and other neurological conditions.
Dr. Benveniste, Principal Investigator and a Professor in the Departments of Anesthesiology and Radiology at Stony Brook University School of Medicine, has used dynamic contrast MRI for several years to examine the glymphatic pathway in rodent models. The method enables researchers to identify and define the glymphatic pathway, where cerebrospinal fluid (CSF) filters through the brain and exchanges with interstitial fluid (ISF) to clear waste, similar to the way the body's lymphatic system clears waste from organs. It is during sleep that the glymphatic pathway is most efficient. Brain waste includes amyloid β (amyloid) and tau proteins, chemicals that negatively affect brain processes if they build up.
In the paper, "The Effect of Body Posture on Brain Glymphatic Transport," Dr. Benveniste and colleagues used a dynamic contrast MRI method along with kinetic modeling to quantify the CSF-ISF exchange rates in anesthetized rodents' brains in three positions -- lateral (side), prone (down), and supine (up).
"The analysis showed us consistently that glymphatic transport was most efficient in the lateral position when compared to the supine or prone positions," said Dr. Benveniste. "Because of this finding, we propose that the body posture and sleep quality should be considered when standardizing future diagnostic imaging procedures to assess CSF-ISF transport in humans and therefore the assessment of the clearance of damaging brain proteins that may contribute to or cause brain diseases."
It was found that the material exchange efficiency of cerebrospinal fluid (CSF) and interstitial fluid (ISF) was the highest in the right lying position and the lowest in the prone position. The reason may be that the heart position is higher in right lying position, which can promote blood suction and venous return, increase cardiac output, improve cerebral artery pulsation and thus improve the material exchange efficiency of CSF and ISF; while in prone position, the head is relatively higher, CSF outflow along neck vessels increases, which can reduce CSF in the brain, resulting in decreasing of the material exchange efficiency of CSF and ISF.
A left lateral body position increases pulmonary vein stress in healthy humans
Pulmonary vein (PV) stretch is proarrhythmic for atrial fibrillation (AF). AF patients often report that a left lateral (LL) body position can trigger arrhythmia symptoms. Because the PV myocardium is thought to trigger AF, we hypothesized that the LL compared to the supine body position...
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