SLEEP DENTISTRY/SCREENING FOR SLEEP DISORDERS
Snoring – the Silent Killer
An American research study showed that in a 30 to 45 year old population, 20% of men and 5% of women will snore, and by the age of 60, 60% of men and 40% of women will snore habitually. Obstructive Sleep Apnea (OSA) is a common sleep disorder and is estimated to have an incidence of 24% in men and 9% in women in the US. Many authorities believe that up to 93% of females and 82% of males with moderate to severe OSA remain undiagnosed.
A recent report in Singapore, published in The Straits Times, showed that 1 in 3 Singaporeans have Snoring/Obstructive Sleep Apnea, and 1 in 3 of these patients have moderate to severe OSA.
Obstructive Sleep Apnea is related to reduced airflow through the upper airway during sleep. This is due to complete or partial upper airway obstruction or increased upper airway resistance.
Snoring is frequently deemed as a social nuisance. Not a nuisance to the snorer, but a nuisance to the bed-partner. The presence of snoring is an ‘alarm’ that alerts one to the possibility of OSA. Snoring implies an increased resistance to the inflow of air during breathing at the level of the upper airways.
Snoring is due to the vibration of the tissues in the nose, mouth and oral cavity (namely the soft palate, uvula, tonsils, base of tongue and lateral side walls of the mouth). The vibration of excess tissue and the narrow airway leads to collapse, partial or complete, of these structures, which then leads to upper airway obstruction during sleep. This upper airway obstruction cause stoppages in breathing (apnea) and low oxygen at night during sleep. This results in increased heart rate (as the heart is trying to compensate for the low oxygen), and increased blood pressure (hypertension). Hence, the patient with OSA has poor quality unrested sleep.
DURING THE NIGHT
Commonest clinical symptom for patients with OSA is snoring.
Most of my patients come to see me saying: “Hey doc, you know I snore; but you know what, it doesn’t bother me, it bothers my wife!” This would be the social aspect behind the snoring.
Frequently, the bed partner prompts the patient to see a sleep doctor because of concerns over repeated choking at night/gasping/apneas (stoppages in breathing). Patients may complain of frequent awakenings with a choking and gasping sensation, teeth grinding, nocturia (frequent passing urine at night), or nightmares. Many bed partners have witnessed their partners choking and holding their breaths during their sleep. Patients with severe OSA may be unable to sleep supine (on their back), as this causes the tongue to fall backwards resulting in obstruction of the airway.
DURING THE DAY
Common daytime patient complaints include early morning tiredness and morning headaches (attributable to the repetitive nocturnal low oxygen levels). Morning dry mouth and throat are caused by mouth-breathing and snoring. Other symptoms include forgetfulness, depression, irritability and, less commonly, impotence.
Excessive daytime sleepiness is very common in patients with OSA, and is caused by a combination of frequent arousals, sleep fragmentation, repetitive oxygen desaturations, and reductions in delta and rapid eye movement (REM) sleep. Excessive daytime sleepiness can be measured by a simple questionnaire known as the Epworth’s Sleepiness Score (ESS) (see figure below).
The commonest symptoms related to obstructive sleep apnea are:
During the day:
During the night:
|Activity||Chance of Dozing|
|Sitting and Reading|
|Sitting inactive in a public place (Meeting, theatre)|
|A passenger in a car for one hour without a break|
|Lying down in the afternoon when circumstances permit|
|Sitting and talking to someone|
|Sitting quietly after lunch without alcohol|
|In a car, while stopped for a few minutes in traffic|
Each question is rated from a zero to a three.
A final score of zero (minimum) to 24 (maximum). In general, a score less than 10 is considered normal, any result between 11 to 14 is considered fairly sleepy, and any score above 14 is considered sleepy. A score of 20 to 24 is a dangerous patient who might fall asleep anytime, even when driving.
Clinical evaluation is the most important step in managing a patient with snoring and/or sleep apnea. An ear, nose and throat endoscopic examination of the upper airway assessment is crucial.
All patients should have weight and height recorded, body mass index (BMI) calculated, blood pressure taken, and neck circumference measured.
AIRWAY ASSESSMENT IS MOST IMPORTANT
The upper airway assessment is the most important step in the evaluation of the snoring patient. This would be fundamental, in assessing and deciding the modality of treatment in all snoring/sleep apnea patients.
Based on the patient’s BMI, neck circumference, oral cavity adequacy, tonsil size, palate size/length, tongue size, upper airway assessment, and the nasal passage size, the modality of treatment is decided together with the patient.
Treatment of snoring and sleep apnea may be conservative and/or surgical (see chapter on Treatment of Snoring/Sleep Apnea).
Many studies have shown that the symptoms of a patient alone are fairly useful in predicting if one has sleep apnea or not. There are strong indicators of sleep apnea. Many of my younger patients (between 30 to 40 years old) who come to my clinic with severe symptoms of sleep apnea are already on anti-hypertensive (high blood pressure) medication.
It is not normal for a young male to have high blood pressure; an underlying cause should be sought for. There are some strong tell tale symptoms of sleep apnea. If you snore and have excessive daytime sleepiness, you have a close to 70% chance of having sleep apnea. If you snore, have excessive daytime sleepiness and your bed-partner noticed that you stop breathing (or noticed you gasping at night), you have an 80% probability of having sleep apnea. If you snore, have excessive daytime sleepiness, your bed-partner says you stop breathing at night, and you have high blood pressure (hypertension), you have a 90% chance of having sleep apnea.
Some simple questions that you may ask yourself to see if you might have sleep apnea:
At night, while asleep:
If you answer “yes” to any 3 of these questions, there would be a strong probability that you might have sleep apnea.
Nightmare time comes in the wee hours of the morning for people with obstructive sleep apnea. But it’s no dream: That’s when they’re at highest risk of sudden death. It has been said that “Sleep apnea is the phantom cause of heart disease and sudden death”. It is well known that patients with sleep apnea have a 6 times higher risk of dying between midnight and 6am, compared to normal non-apneic patients. As these patients with snoring and sleep apnea have numerous dips in their oxygen levels while asleep, it would not be surprising that they suffer from significant stress on the heart and brain during these low oxygen events. This in turn leads to high blood pressure, lack of oxygen in the blood and hence, strokes, heart attacks and sudden death.
Overall, it is well known that patients with sleep apnea would not live as long as people without sleep apnea. Medical research studies done over 10 years have shown that patients with severe obstructive sleep apnea (patients who stop breathing more than 30 times per hour) have a mortality rate of about 3% per year.
In general, patients with snoring/sleep apnea are classified into those with a “global” problem, i.e. obesity, and those with a “local” anatomical problem (those with huge tonsils, long thick palate, big tongue and/or a small jaw).
Patients with OSA are generally advised:
This is a non-invasive method of treatment, it entails using continuous positive airway pressure (forced air) by a mask worn by the patient on the nose or the face throughout the night (it is somethings compared to a “reversed vacuum cleaner”). For most patients with OSA, it is not easy to wear the mask throughout the entire night and for every night for the rest of his life. Hence, the issue of compliance is a major problem.
The CPAP machine and its mask would only be effective if the patient wears the mask; it would not work if it is kept in the closet. Moreover, many patients wake up with the mask on the floor, and hence, would not use it the entire night. The CPAP machine and mask is as effective as the duration that it is worn.
CPAP IS NOT A CURE, IT IS A CONTROL; IT IS ONLY EFFECTIVE WHEN IT IS WORN ON THE FACE.
The main drawback to the use of nasal CPAP is compliance. Common reasons for poor compliance with nasal CPAP include:
Failure of CPAP
The CPAP machine is effective provided the patient can tolerate it the entire night. Compliance is the main problem. Most people do NOT use the machine the entire night and every night of the week. Hence, the treatment effectiveness is based entirely on the patient’s use.
Oral appliances (like dentures) are designed to bring the mandible (lower jaw) and base of tongue forward, either by stabilizing the lower jaw position during sleep or by attempting to pull the tongue forward, in an effort to increase the posterior airway space. Oral appliances are offered especially when the patient is a poor candidate for surgical intervention, or is unable to tolerate nasal CPAP.
Oral devices can be divided into two basic types:
These oral devices are not for every OSA patient, and also has an issue with patient usage (compliance) and because the lower jaw is held forward at night, the jaw joint might start to hurt or feel the strain.
The key to surgical success is patient selection (for a successful surgery, the doctor has to select the suitable patient).
Success rates of surgery depend on
Severity of OSA can be classified according to the Apnea-Hypopnea Index (AHI) and lowest oxygen saturation level (LSAT). The severity is usually graded as the worst of the two.
|Mild OSA||5-14||86% - 95%|
|Moderate OSA||15-29||75% - 85%|
Type of nose surgery is dependent on the patient’s nose anatomy. In general, the radiofrequency of the inferior turbinates are easy, simple, painless, quick and has minimal side-effects. Other types of nose surgery:
This new technique is minimally invasive surgery; it is safe, convenient and effective in treating sinus diseases.
The recently invented Pang’s Expansion Sphincter Pharyngoplasty technique (invented by Dr Kenny Pang) has been shown to be over 80% effective in patients with obstructive sleep apnea
Types of Palate Surgery
Types of Tongue Surgery
Notes for OSA patients
Many patients who see me present with two ends of the spectrum in sleep disorders, they usually have 2 main complaints:
“Doc, I’m so tired but I just can’t fall asleep!” or
“Doc, I sleep 8-9 hours, but I’m still so tired, I can’t keep awake!”
These sleep disorders range from insomnia (unable to fall asleep) to obstructive sleep apnea (excessive daytime tiredness, unable to keep awake).
Some self administered sleep test questionnaire might help.
These sleep tests are not intended to be diagnostic, they are just helpful for patients who suspect that they have a sleep disorder.
Answer some of these questions:
In general, with more than 5 answers as positive (yes), one should seek a sleep specialist consult. It might indicate that you could have a sleep disorder.
Sleep Assessment Tests
To say that a patient has high blood pressure, one would have to take the blood pressure reading; to say that a patient has diabetes, one would have to take a glucose blood test. Similarly, to diagnose a patient with a sleep disorder, one would have to perform a sleep assessment test.
There are 2 main types of sleep test:
Depending on the type of sleep disorder suspected, the sleep specialist would order the appropriate sleep test. The type of sleep test ordered would be dependent on the number of parameters required.
Overnight Hospital Sleep Test (Polysomnogram)
The in-hospital overnight attended (monitored by a sleep technician throughout the night) sleep test comprises of multiple parameters including:
With these parameters, the sleep specialist would be able to determine the sleep stage (dream sleep versus non-dream sleep), the stoppages of breathing, and whether there is continued chest/abdominal effort to breathe.
Apnea – stoppage in breathing by more than 10 seconds duration
Obstructive – some form of obstruction in the upper airway
In obstructive sleep apnea, there would be no nasal or oral airflow (stoppage in breathing), but there would be persistent effort by the patient to breathe (body trying to breathe despite an obstructed airway).
In central apnea, there would be no nasal or oral airflow (stoppage in breathing), but no effort nor attempts by the body to breathe (brain forgetting to breathe).
Although the in-hospital overnight sleep test is useful, it suffers from a few disadvantages (see figure) namely:
Hence, due to these short-comings of the in-hospital overnight sleep test, many sleep specialists have moved away from asking the patient to stay in hospital for the sleep test and have encouraged patients to monitor their sleep in the comfort of his own home.
Home Based Overnight Sleep Test (done in the patient’s own home)
A wrist-worn device known as the Watch PAT (American FDA approved) has been used to detect OSA. The PAT (peripheral arterial tonometry) technology represents a unique and accurate concept of non-invasive measurement of stress levels that appears to be very accurate for detecting sleep-disordered events (see figure). This is a self-contained device worn around the wrist.
It is lightweight and silent, easy to use, portable, and accurate, which is essential for a practical ambulatory device. Only ONE finger probe is used in this device. One is the optico-pneumatic (light and pressure) sensor that detects the peripheral arterial tonometry (PAT) signal (stress level in the finger); the other measures arterial oxygen saturation (amount of oxygen in the blood). The body of the device also contains an actigraph (which measures and detects muscle tension and tone), which is used to differentiate sleep stages from wakefulness.
Simplistically speaking, the Watch PAT looks at any desaturation in oxygen level in the blood and correlates this with the arterial tone in the finger probe.
Pang K.P. and his researchers found that this wrist worn device had very close correlation and accuracy with the in-hospital overnight sleep test. As discrete obstructive airway events (i.e. stoppages in breathing) cause stress to the heart, lungs and brain, this increases arousal from sleep, stress activation and hence these events would markedly increase peripheral arterial tone (finger tone) signal. Many other authors have also found good correlation between the Watch PAT and the overnight sleep study in the hospital.
Suffice to say, the paradigm has shifted from the cumbersome in-hospital laboratory overnight sleep test, to the convenient, cheaper and accurate home based device (Watch PAT). It is of important note that the Watch PAT is already FDA approved in the United States of America and most insurance companies in the USA recognize its advantages and are proponents of it.