Research on Sleep Disorders
- Who are at risk for sleep disorders?
Some sleep disorders have a genetic component and may run in families, such as restless legs syndrome, obstructive sleep apnoea, narcolepsy and the parasomnias. People who have irregular sleep schedules, including shift workers and those who travel across multiple time zones frequently are also at increased risk of developing sleep related problems. Lifestyle factors such as excessive caffeine consumption, lack of regular exercise, poor stress management and smoking all contribute to sleep disturbances. In general, the quality of sleep declines with age. As a result of this, as well as degenerative changes and weight gain which increase with age, sleep related disorders tend to become more frequent as we grow older.
- How are sleep disorders diagnosed?
Most sleep disorders can be diagnosed with a good sleep history, including questions about the patient's sleep habits, lifestyle, medications and a physical examination. A sleep study may be required in some patients.
- What is a sleep study?
Sleep patterns can be studied in the laboratory using machines which record brainwave activity, breathing, heart rate and limb movements during sleep. The most common types of sleep studies are: * Overnight polysomnography (PSG) * Daytime nap test (also known as the multiple sleep latency test or MSLT). PSG involves staying overnight in the sleep laboratory and being hooked up to a machine which is monitored by sleep technologists. At least 6 hours of sleep are recorded using electrodes attached to the scalp and limbs, special belts across the chest and abdomen, airflow monitors and ECG leads. PSG is usually indicated in patients in whom sleep related breathing disorders and abnormal movements in sleep are suspected. The MSLT follows the overnight PSG, comprising four 20-minute naps at 2 hour intervals throughout the day. It is indicated for the diagnosis of narcolepsy and also to assess the severity of sleepiness in patients who complain of excessive daytime sleepiness.
