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The Science of Slumber

A look at common sleep disorders, and how clinicians at CGH are tackling them.

Singaporeans have one of the longest working hours in the world, and getting good-quality sleep seems to have taken a back seat. Inadequate sleep can lead to health complications, affects a person’s ability to concentrate, increases the chances of being forgetful, and impairs cognitive abilities in the long run. Yet this trend of poor sleep practices in Singapore continues. Over 40% of working adults in the country have insufficient sleep on weekdays.

In conjunction with World Sleep Day, we share more about the commonly-seen sleep disorders at Changi General Hospital (CGH). The Changi Sleep and Assisted Ventilation Centre provides a comprehensive assessment, diagnosis and treatment service to patients with different types of sleep disorders.

The Centre adopts a multi-disciplinary approach, combining the expertise of specialists from the departments of Ear, Nose and Throat (Otolaryngology), Respiratory Medicine, Dental, Sports Medicine, General Surgery and Psychological Medicine.

Many of these sleep conditions are intricately linked to other medical issues, for example, breathing issues, amongst others. A multi-disciplinary approach enables specialists across different teams to collaborate closely to diagnose and treat the sleep disorders.

OSA is a common sleep disorder that has been estimated to affect about 30% of Singapore’s population.

OSA is a condition in which the upper airway collapses repeatedly during sleep, resulting in sleep disturbances and a drop in body oxygen levels. This in turn leads to excessive daytime sleepiness that can affect work performance and increase the risk of motor vehicle accidents.

OSA patients are also at increased risk of numerous medical conditions such as heart attack, abnormal heart rhythm, difficult-to-treat high blood pressure, stroke, depression and cognitive impairment.

What are the risk factors?

Common risk factors for OSA are obesity, age, male gender, menopause in females, smoking, having a narrow upper airway as well as a family history of OSA.

Diagnosing OSA

A sleep study is necessary for the evaluation and diagnosis of OSA. The gold standard diagnostic sleep study is an overnight test conducted in a laboratory. During the study, special sensors will monitor the patient’s brainwaves, airflow from the nose and mouth, level of oxygen in the blood and muscle activity while he or she is asleep. Home sleep testing is also available but it is not suitable for everyone. Patients should discuss with their doctor on which sleep studies are suitable for them.

Treating OSA

OSA is treated through Continuous Positive Airway Pressure (CPAP) therapy. The CPAP device delivers pressurised air to the upper airway, preventing it from collapsing during sleep. The device needs to be worn every night during sleep for the treatment to be effective.

In the event one is unable to tolerate CPAP therapy, alternate treatment options such as oral appliances and surgery may be considered. Additional recommended lifestyle interventions would include weight reduction, smoking cessation and the maintenance of good sleep hygiene.

Insomnia is a sleep disorder where a person experiences dissatisfaction of sleep quantity or quality. It may be related to difficulty initiating sleep, difficulty maintaining sleep, or early morning awakening with an inability to return to sleep.

It is a common complaint, with some 15% of the local population suffering from it. Insomnia disorder is diagnosed in people who suffer from frequent insomnia that causes distress or impairment in daytime functioning, over a period of time.

Causes of Insomnia

A wide range of factors contribute to insomnia. Poor sleep habits, such as irregular bedtimes and the use of electronic devices in bed, are common reasons. Psychological factors, such as stress and anxiety, are also another major cause.

Often, people who experience insomnia worry about their sleep, which further exacerbates the condition. Other contributing factors include caffeine use, smoking and alcohol. Although alcohol helps initiate sleep, it is damaging to sleep quality.

Sleep studies are conducted at the Changi Sleep Laboratory by our sleep technologists.

Medical conditions such as hyperthyroidism or ailments that cause pain also make it difficult to enjoy good sleep. Some sufferers have problems with their body clock control and have circadian rhythm disorders. Finally, a minority have primary insomnia, which is not contributed by other causes.

Diagnosing Insomnia

Insomnia may be evaluated by a psychiatrist or a sleep specialist, who will perform a detailed enquiry about the patient’s sleep routine, associated habits, and evaluate for possible causes contributing to the symptoms.

The doctor may ask for certain investigations, such as the use of a sleep diary, rating scales, or a sleep study (also known as polysomnography) to aid in the assessment. Most patients with uncomplicated insomnia do not require polysomnography.

Treating Insomnia

There is a wide range of treatment strategies available for insomnia. One of the most effective is cognitive behavioural therapy, which involves modifying and improving habits, emotions and thought processes related to sleep. This is usually performed by a clinical psychologist.

There are also pharmacological treatments such as prescription sleeping pills. However, as these run the risk of dependence, they are recommended only for short-term use. The doctor will advise on the most suitable treatment based on the nature and underlying causes for the particular patient’s insomnia.

The Science of Slumber