Sleep Apnea

 

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Definition/Description

Sleep apnea is a disorder in which breathing is interrupted or paused during sleep. The pauses in breathing can last a few seconds to minutes and are long enough to:

• Disrupt sleep
• Decrease level of oxygen in the blood
• Increase level of carbon dioxide in the blood

These breathing interruptions can occur more than 30 times an hour and significantly impair the quality of sleep. Because of this, sleep apnea is a leading cause of excessive daytime sleepiness.
There are three types of sleep apnea: central, obstructive and mixed. Obstructive sleep apnea is the most common and the main focus of this article.

1. Obstructive sleep apnea (OSA) is caused by repeated partial or complete obstruction of the upper airway that diminishes or stops breathing. 
2. Central sleep apnea occurs when the brain is less sensitive to changes in carbon dioxide levels in the blood and fails to send signals to the respiratory muscles to breathe deeper.
3. Mixed sleep apnea is a combination of both obstructive and central sleep apnea episodes.

Aetiology

Sleep apnea occurs when there is not enough space to accommodate sufficient airflow in a portion of the upper airway during sleep.

• When muscle tone is decreased, the result is a repetitive total or partial collapse of the airway.
• In children, the most common cause of obstructive sleep apnea is enlarged tonsils and/or adenoids.
• In adults, it is most commonly associated with obesity, male sex, and advancing age.

Factors that contribute to airway obstruction are:

• Obesity
• Large neck circumference
• Large tongue or tonsils
• Narrow airway due to bony structures of head and neck
• Taking sedative medication
• Drinking alcohol
• Smoking
• Nasal congestion

Medical disorders associated with OSA include:

• Stroke
• Hypothyroidism
• Metabolic syndrome
• Acromegaly
• Neurological disorders (eg myasthenia gravis)

Epidemiology

• In the United States, it has been reported that 4% of men and 2% of women meet criteria for obstructive sleep apnea.
• More recently, prevalence has been reported to be as high as 14% of men and 5% of women in the United States.
• Prevalence is higher in Hispanic, African American, and Asian populations.
• Prevalence also increases with age, and when individuals reach 50 years of age or more, there are as many women as men who develop the disorder. 
• Genetics and abnormalities or conditions of the craniofacial morphology also increase the likelihood of OSA. Individuals with a first-degree relative with OSA were at a 1.5-2x increased risk of developing OSA.
• OSA is common in individuals who spend long periods of time sitting and driving, such as commercial truck drivers.

Characteristics/Clinical Presentation

Typical adult obstructive sleep apnea patient

• Overweight or obese middle-aged male or postmenopausal female with excessive daytime sleepiness and loud nightly snoring.
• May also complain of waking to gasp for breath or choking, sleep maintenance insomnia, night sweats, nighttime reflux, and nocturia in the absence of excessive nighttime liquid intake.
• Typically larger than average neck circumference (17 inches in males) with crowded oropharynx and large tongue.
• Retrognathism (an abnormal posterior positioning of the maxilla or mandible relative to the facial skeleton and soft tissues) may be present.

Patients with refractory atrial fibrillation, resistant hypertension, and history of a stroke should be screened for sleep apnea regardless of symptoms

Typical child with obstructive sleep apnea

• Loud nightly snoring
• May be hyperactive rather than sleepy
• May have academic difficulties.
• These children can be incorrectly diagnosed with attention deficit hyperactivity disorder (ADHD).
• Night sweats, nighttime reflux, sleep maintenance insomnia, restless sleep with frequent limb movements, and secondary nocturnal enuresis may also be present.
• A physical exam is often notable for adenoidal facies ( long, open-mouthed face of children with adenoid hypertrophy), tonsillar hypertrophy, hyponasal speech, and high arched palate.

Patients with Down syndrome and any other condition associated with hypotonia should be screened for obstructive sleep apnea regardless of symptoms.

Treatment

For adults, the use of continuous positive airway pressure (CPAP) is the most effective treatment

• Adherence to nightly CPAP use can result in near complete resolution of symptoms.
• For patients unable or unwilling to use CPAP or those who will be unable to access electricity reliably, custom fitted and titrated oral appliances can be used to bring the lower jaw forward and relieve airway obstruction.
• Severe obstructive sleep apnea can be treated with BiPAP as well and is better tolerated by patients who require higher pressure settings (greater than 15 cm to 20 cm H2O).
• For all patients, it is important to address any concomitant nasal obstruction with nasal steroids for allergic rhinitis or surgically for nasal valve collapse.
• For obstructive sleep apnea with a strong positional component. Positioning devices to keep a patient on his or her side can be an option.
• Weight loss is recommended and can often decrease the severity of obstructive sleep apnea, it is not usually curative by itself.

• The primary treatment for obstructive sleep apnea in a child is tonsillectomy and adenoidectomy. The consideration for surgery should be balanced with the severity of symptoms, physical exam, and age. In mild cases, a trial of montelukast and nasal steroids may be enough to reduce the apnea-hypopnea index to goal.
• There are surgical options for adults, but these are usually reserved for severe obstructive sleep apnea and patients unable to tolerate noninvasive treatment modalities due to surgical risks and varying efficacy.

Evaluation

• Nighttime in-laboratory Level 1 polysomnography (PSG) is the standard gold test for diagnosis of obstructive sleep apnea. During the test, patients are monitored with EEG leads, pulse oximetry, temperature and pressure sensors to detect nasal and oral airflow, respiratory impedance plethysmography or similar resistance belts around the chest and abdomen to detect motion, an ECG lead, and EMG sensors to detect muscle contraction in the chin, chest, and legs. A hypopnea can be based on one of two criteria. It can either be a reduction in airflow of at least 30% for more than 10 seconds associated with at least 4% oxygen desaturation or a reduction in airflow of at least 30% for more than 10 seconds associated with at least 3% oxygen desaturation or an arousal from sleep on EEG.
• Home sleep tests (HST) have gained popularity due to their relative accessibility and lower cost. They are appropriate for adults with a high pretest probability for sleep apnea and no significant medical comorbidities (advanced congestive heart failure, COPD, and neurologic disorders). These are level 3 sleep tests consisting of pulse oximetry, heart rate monitoring, temperature and pressure sensors to detect nasal and oral airflow, resistance belts around the chest and abdomen to detect motion, and a sensor to detect body position.

Other testing may include

• History: possible risk factors, co-morbidities, snoring, and what a normal night of sleep is like to him/her.
• Indices: AHI (apnea-hypopnea index), RDI (respiratory disturbance index)
• Clinical Examination: nose, tonsils, palate, tongue, neck circumference, upper airways.  Findings are predominantly inconclusive and requires training for proper assessment.
• Questionnaires: Epworth Sleepiness Score (ESS) for daytime sleepiness; Berlin questionnaire for common OSA risk factors and symptoms.
• Oximetry: analyse oxygen saturation of haemoglobin to help identify individuals unlikely to have OSA.

Morbidities associated with OSA

• OSA induced biological changes include intermittent hypoxia, intermittent hypercapnia, intrathoracic pressure changes, sympathetic activation and sleep fragmentation.
• OSA can cause metabolic dysregulation, endothelial dysfunction, systemic inflammation, oxidative stress and hypercoagulation, and neurohumoral changes.
• There is evidence suggesting that OSA is independently associated with metabolic syndrome.
• OSA has been shown to increase the risk for systemic hypertension, pulmonary vascular disease, ischemic heart disease, cerebral vascular disease, congestive heart failure and arrhythmias

Physical Therapy Management

Although there is little research providing sound evidence based physical therapy interventions for OSA at this time, it often goes undiagnosed providing opportunities for physical therapists to identify, educate and refer patients who present with signs and symptoms of OSA.

Undiagnosed OSA is associated with increased risk of hypertension, cardiovascular disease, motor vehicle accidents and reduced quality of life.  

Physical Therapists can educate patients on OSA:

• Signs and symptoms
• Risk factors
• Associated co-morbidities
• How to get diagnosed/tested
• Risks of undiagnosed OS

Aerobic Exercise

Studies show significant effect of exercise in reducing the severity of sleep apnea in patients with OSA with minimal changes in body weight. The interventions typically involved aerobic activities for 30 minutes minimum on 3-5 days a week. The significant effects of exercise on cardiorespiratory fitness, daytime sleepiness, and sleep efficiency indicate the potential value of exercise in the management of OSA.

An example of physiotherapy intervention

• Supervision of 150 min/week of aerobic exercise (treadmill, elliptical trainer, or recumbent bicycle), performed at 60 % of heart rate reserve, spread across 4 days/week for 12 week

• On 2 days/week for 12 week, aerobic exercise was followed by resistance exercise, consisting of 2 sets of 10–12 repetitions for 8 different exercises

Tongue Exercises

Physiotherapeutic treatment eg muscular exercises could have a place in the treatment ofOSA, particularly in the mild cases. This treatment could help to prevent the muscular hypotonia that develops progressively in the OSA.

Below shows examples of exercises For Obstructive Sleep Apnea

EXERCISES FOR THE TONGUE
TONGUE BRUSHING
Method:
1. With your toothbrush brush the top and sides of your tongue, while your tongue is sitting on the floor of your mouth.
2. Repeat the individual sections 5 times each.
3. Complete the exercise three times daily.
Purpose – to strengthen the tongue muscles-with the added advantage of maintaining great oral hygiene!

TONGUE SLIDE
Method:
1. Looking straight ahead, position the tip of your tongue against the back of your top, front teeth.
2. Slide your tongue backward.
3. Repeat 10 times.
Purpose – to tone and strengthen the tongue and throat muscles.

TONGUE FORCES
Method:
1. Forcibly suck your tongue upward until the whole tongue is against your palate.
2. Hold this position for 4 seconds.
3. Repeat 5 times.
Method:
1. Force the back of your tongue downward until the whole tongue is resting on the floor of your mouth.
2. Keep the tip of your tongue touching the back of your lower teeth.
3. Hold for 4 seconds.
4. Repeat 5 times.
Purpose - both of these exercises strengthen the tongue and tone your soft palate.

TONGUE PRESS
Method:
1. Push your tongue against your hard palate (the top and front of your mouth).
2. Do this for 5 seconds.
3. Slide your tongue backward to the back of your mouth.
4. The initial third of your tongue should be against your hard palate, not just the tip.
5. Keep your jaw open throughout the exercise.
6. Refrain from biting down - keep your teeth apart.
7. Repeat this movement 10 times.
8. Repeat 4 times a day.
Purpose – to strengthen the genioglossus (the main muscle used for sticking your tongue out), and to increase the strength in the hyoid muscles and bone. The hyoid bone is located in the centre of the neck. It sits between the chin and thyroid cartilage.
The exercise assists by putting the hyoid bone in the correct position and keeping it there1.
The hyoid bone is a free moving, u-shaped bone in the neck. The volume of the tongue should reduce too.

Breathing Exercise

Diaphragmatic Breathing

Respiratory training was found to have significant effect of sleep apnea, as shown by in the 2021 systematic review were patients with sleep apnea that underwent respiratory retraining had a measurable improvement in  apnea-hypopnea indexes (AHI).

There is a diversity of breathing retraining methods that were found to improve sleep apnea including:  inspiratory resistance training and diaphragmatic breathing. Also, they were found helpful in decreasing fatigue and day time sleepiness.

Inspiratory resistance training involves using an inspiratory threshold training device, examples for these devices include POWER breathe.

Diaphragmatic breathing involves patients taking slow and deep breathes, inhaling through their nose and exhaling through their mouth, placing a hand on their abdomen aiming to lifting it during inspiration.

Regular practice of breathing control activities such as singing and playing wind instruments may also be helpful for people with sleep apnea.

Differential Diagnosis

• Asthma
• Central sleep apnea
• Chronic Obstructive Pulmonary Disease
• Depression
• Gastroesophageal reflux
• Hypothyroidism
• Narcolepsy
• Periodic limb movement disorder

Case Reports/ Case Studies

1. Daoulah A, Ocheltree S, Al-Faifi S, Ahmed W, Asrar F, Lotfi A. Sleep apnea and severe bradyarrhythmia – an alternative treatment option: a case report. J Med Case Reports 2015; 9(1): 113-117. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4437673/ (OSA and Bradyarrhythmia)
2. Guimarães T, Colen S, Cunali P, Rossi R, Dal-Fabbro C, Ferraz O, et al. Treatment of obstructive sleep apnea with mandibular advancement appliance over prostheses: A case report. Sleep Science 2015;8(2):103-106.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608885/ (Treatment of OSA with Mandibular Appliance)
3. Fang H, Miao N, Chen C, Sithole T, Chung M. Risk of Cancer in Patients with Insomnia, Parasomnia, and Obstructive Sleep Apnea: A Nationwide Nested Case-Control Study. J Cancer 2015;6(11):1140-1147. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4615350/ (OSA and Cancer)
4. Cadby G, McArdle N, Briffa T, Hillman D, Simpson L, Knuiman M, et al. Severity of OSA Is an Independent Predictor of Incident Atrial Fibrillation Hospitalization in a Large Sleep-Clinic Cohort Chest. 2015;148(4):945-952.http://www.sciencedirect.com/science/article/pii/S0012369215502833 (OSA and A-fib)
5. Meuleners L, Fraser M, Govorko M, Stevenson M. Obstructive Sleep Apnea, Health-Related Factors, and Long Distance Heavy Vehicle Crashes in Western Australia: A Case Control Study. Journal of Clinical Sleep Medicine 2015; 11(4): 413-418.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4365454/ (OSA and MVA)