Now that we've discussed the basics of what Orofacial Myofunctional Therapy is, let's dive deeper into one of the primary concerns of airway providers: sleep-disordered breathing (SDB).
SDB is an all-encompassing term for breathing difficulties or interruptions during sleep.
SDB ranges from snoring to upper airway resistance syndrome (UARS) to obstructive sleep apnea (OSA), which are conditions where part or all of the airway is blocked during sleep.
[4]
Important definitions [4, 5]
Apnea - an airflow decrease of greater than 70% that lasts at least 10 seconds
Hypopnea - a 30-70% decrease in airflow for at least 10 seconds with an associated 3-4% fall in oxyhemoglobin saturation
Apnea-hypopnea index (AHI) - the average frequency of apnea and hypopnea events per hour of sleep
Obstructive sleep apnea - AHI ≥5 associated symptoms such as daytime sleepiness, impaired cognition, mood disorders, insomnia, hypertension, heart disease, and history of a stroke
Central sleep apnea - AHI ≥5 or ≥50% of the respiratory events occur without any inspiratory effort
Note: the presence of inspiratory effort during apneas and hypopneas is what differentiates obstructive sleep apnea and central sleep apnea
Snoring is an initial indication of breathing restrictions that often develop further into UARS, which shows a higher rate of sleep interruptions and fragmentation but does not have true apneic events where breathing is fully interrupted as seen with OSA.
UARS characteristics include frequent sleep arousals (also known as microarousals) that occur during the transition from deep stages of sleep to shallower stages of sleep in response to increased respiratory effort as a result of upper airway narrowing. [6, 9]
A certain amount of spontaneous microarousals are an intrinsic part of physiological sleep, but excessive arousal can disrupt healthy sleep, and frequent sleep arousal has been linked to daytime sleepiness, declines in cognitive performance, weight gain, depression, heart disease, and diabetes.
Trained airway providers know to look for common structural, functional, and behavioral features associated with sleep-disordered breathing, which often include one or several of the following signs/symptoms [7, 10]
Snoring - the most obvious symptom of SDB is loud snoring that is present on most nights
Waking with a dry mouth
Irritability - an individual with SDB may become irritable, have daytime sleepiness, or have difficulty concentrating and display hyperactive behavior similar to ADD/ADHD
Bedwetting of frequent nighttime urination
Morning headaches or facial tension
Slow growth - children with SDB may not produce enough growth hormone, resulting in abnormally slow growth and development
Cardiovascular difficulties - OSA can be associated with an increased risk of high blood pressure or other heart and lung problems
ADD/ADHD-type symptoms
Obesity - SDB may cause the body to have increased resistance to insulin, and daytime fatigue can lead to decreased physical activity
Gasping for air during sleep
For children, enlarged tonsils and adenoids that compromise the upper airway volume are generally considered the most common cause of snoring and OSA. [8]
Approximately 10% of children snore regularly; About 2-4% of
children experience OSA. [7]
Recent studies indicate that mild SDB or snoring may cause many of the same problems as OSA in children. [7]
The list below shows the multifactorial connections between lifestyle choices, genetics, and behavior and their impact on sleep-disordered breathing risks.
Risk assessment [2, 10]
Age - sleep apnea can occur at any age, but risk increases with age
Endocrine disorders or changes in hormone levels - hormone levels can affect the size and shape of the face, tongue, and airway
Hypothyroidism, high insulin levels, or high growth hormone
levels lead to an increased risk of OSA
Family history and genetics - genes help determine the size and shape of the skull, face, and upper airway while also increasing the risk of other health conditions that can lead to sleep apnea, such as cleft lip
Heart or kidney failure - these conditions can cause fluid to build up in the neck, which can block the upper airway
Large tonsils and a thick neck - these features narrow the upper airway
Also having a large tongue and/or low tongue posture can make it
easier for the tongue to block the airway during sleep
Nasal congestion - difficulty with nasal breathing, whether from anatomical challenges or allergies, increases the risk of OSA
Medical conditions - congestive heart failure, high blood pressure, type 2 diabetes, PCOS, prior stroke, and chronic lung diseases may increase the risk of OSA
Lifestyle habits - drinking alcohol and smoking can increase the risk of sleep apnea
Alcohol can make the muscles of the mouth and throat relax,
which may close the upper airway
Smoking can cause inflammation in the upper
airway, which affects breathing
Obesity - this condition is a common cause of OSA due to increased fat deposits in the neck that block the upper airway
Sex - men are more likely to have severe sleep apnea and to get sleep apnea at a younger age than women
In both children and adults, obesity has been shown to be an independent and key risk factor in OSA, the prevalence of which is estimated to be as high as 45% in obese subjects. [11]
A 10% reduction in body mass has been shown to result in an improvement in the number of OSA events by 25%. [11]
Overall, when breathing is disrupted during sleep, the body thinks it's choking, heart rate increases, blood pressure rises, the brain is aroused, and sleep is disrupted.
"The consequence of the interruption of normal sleep and breathing patterns due to SDB is a reduction in oxygen levels, which has been shown to trigger a cascade of events causing oxidative stress, metabolic alterations, damage to the vascular endothelium, and resultant inflammation. It is this systemic inflammatory response that has been linked to an increased risk of insulin resistance, abnormal lipid profiles, and other metabolic abnormalities [11]."
Another key nutrient lost with improper breathing habits -- whether during sleep or with daytime mouth breathing -- is nitric oxide (NO).
NO is an important signaling molecule in the cardiovascular system that relaxes smooth muscles and has antithrombotic, antiproliferative, and anti-inflammatory properties. [1]
Low levels of nitric oxide are associated with impaired endothelial function; Endothelial dysfunction promotes atherosclerosis and cardiovascular diseases along with hypertension, hypercholesterolemia, and diabetes mellitus. [1, 3]
Early morning circulating nitric oxide levels are lower in subjects with OSA compared with control subjects without OSA;
The more severe the sleep apnea, the greater the nitric oxide suppression. [3]
The predominant test for diagnosing OSA at this time is a polysomnography
(i.e. a sleep test). [4]
These are often done in a sleep lab or hospital setting, but more options are becoming available for at-home testing as well. For reliability, the primary requirement of all sleep tests is that a trained sleep physician must interpret the results to fully understand where a patient is on the sleep-disordered breathing spectrum.
The prevalence of OSA in adults is approximately 13% of men and 6% of women with children ranging in prevalence from 1.2% to 5.7%, making this a disease that is likely to be encountered by most clinicians in the dental profession. [11]
Although myofunctional therapists, dental hygienists, and other dental care providers cannot diagnose sleep disorders, having a solid understanding of the signs and symptoms of each phase in the sleep-disordered breathing continuum should be seen as the new standard of care. Detection of sleep-related diseases early on in growth and development is imperative to preventing the progression of several systemic complications and truly optimizing our patient’s whole-body health.
Talk soon,
Liz Laney, Myofunctional Therapist
*None of the information included in this post is intended to be medical advice. Please talk with your healthcare provider(s) before making lifestyle changes or starting/stopping any medications and/or diets.
Resources
1. Badran M, Golbidi S, Ayas N, Laher I. Nitric Oxide Bioavailability in Obstructive Sleep Apnea: Interplay of Asymmetric Dimethylarginine and Free Radicals. Sleep Disord. 2015;2015:387801. doi:10.1155/2015/387801 2. Causes and risk factors. National Heart Lung and Blood Institute. Accessed August 18, 2023. https://www.nhlbi.nih.gov/health/sleep-apnea/causes. 3. IP MSM, LAM B, CHAN L-Y, et al. Circulating nitric oxide is suppressed in obstructive sleep apnea and is reversed by nasal continuous positive airway pressure. American Journal of Respiratory and Critical Care Medicine. 2000;162(6). doi:10.1164/ajrccm.162.6.2002126 4. Jaffe F, Markov D, Doghramji K. Sleep-disordered breathing: in depression and schizophrenia. Psychiatry (Edgmont). 2006;3(7):62-68. 5. Khawaja IS, Kazaglis L, Hashmi A, Khurshid KA, Eiken C, Hurwitz TD. Obstructive sleep apnea and Depression: A review. Psychiatric Annals. 2016;46(3):187-191. doi:10.3928/00485713-20160125-02 6. Pandey A, Vala B, Shah M. Upper Airway Resistance Syndrome. Int J Head Neck Surg 2019;10(1):18–21. 7. Pediatric sleep-disordered breathing. ENT Health. December 2018. Accessed August 18, 2023. https://www.enthealth.org/conditions/pediatric-sleep-disordered-breathing/. 8. Pirila-Parkkinen K, Pirttiniemi P, Nieminen P, Tolonen U, Pelttari U, Lopponen H. Dental arch morphology in children with sleep-disordered breathing. 2008;31(2):160-167. doi:10.1093/ejo/cjn061 9. Qian X, Qiu Y, He Q, et al. A Review of Methods for Sleep Arousal Detection Using Polysomnographic Signals. Brain Sci. 2021;11(10):1274. Published 2021 Sep 26. doi:10.3390/brainsci11101274 10. Sleep apnea. Mayo Clinic. April 6, 2023. Accessed August 18, 2023. https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631#:~:text=Obstructive%20sleep%20apnea%20occurs%20when,breathing%20is%20momentarily%20cut%20off. 11. Sleep disordered breathing and dentistry: Waking up to reality. Pocket Dentistry. January 9, 2020. Accessed August 18, 2023. https://pocketdentistry.com/sleep-disordered-breathing-and-dentistry-waking-up-to-reality/.
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