Sleep disorders: Screening, assessment and diagnosis
Types of sleep disorders
Although there are more than 80 different sleep disorders, the simplistic classification of problems of too little sleep (insomnia), too much sleep (hypersomnia, excessive sleepiness), circadian rhythm problems and "things that go bump in the night" (parasomnias) is a useful rubric for classifying symptoms and managing sleep disorders.
Insomnia and excessive sleepiness are the most common presenting complaints in primary care.
Screening for insomnia
Insomnia is defined as a persistent difficulty falling asleep or staying asleep, awakening earlier than the person wishes or having non-restorative sleep despite adequate circumstances for sleep. Acute insomnia lasts for less than a month and is usually triggered by acute medical illness or stress. Chronic insomnia persists for more than 30 days and, if untreated, often lasts for decades.
The Athens Insomnia Scale (Soldatos et al., 2000) is a self-report questionnaire that patients can complete in five minutes in the clinician's office. If the person scores a total higher than 10 (Soldatos et al., 2003), assess:
- sleep schedule and sleep hygiene
- anxiety or worry at night
- daytime functioning
- medical disorders
- substance use
Sleep schedule and sleep hygiene
Collect information on bedtime, the time it takes the patient to fall asleep, the number and duration of nighttime awakenings, the final awakening in the morning, the time the patient takes to get out of bed and the difference between weeknight and weekend sleep schedules and sleep quality. Learn about bedtime routine and any disturbing factors in the sleep environment such as television, computers or telephones.
Anxiety or worry at night
Ask patients about anxiety, worry, frustration, problem-solving, rumination about stressful issues and the inability to "switch off" their mind when they are lying awake in bed at night.
Assess daytime sleepiness, mental and physical fatigue, problems with concentration and memory, and inquire about mood and irritability. Daytime sleepiness is usually not the leading daytime symptom of insomnia. Patients more often complain about mental exhaustion and an inability to nap during the day.
Screen for specific sleep disorders and medical and psychiatric conditions that may cause insomnia.
Review medications that have a CNS-stimulating effect or disrupt sleep, such as diuretics.
Inquire about caffeine and other substance use. Consider whether the patient is experiencing alcohol withdrawal.
Excessive sleepiness: Screening for apnea
Excessive sleepiness is characterized by a complaint of constant or recurrent daytime sleepiness, typically with inappropriate sleep episodes. All patients who are tired, sleepy or fatigued should be screened for sleep apnea.
A short questionnaire to assess excessive sleepiness is the Epworth Sleepiness Scale. Most patients can complete the scale in two to three minutes. A score of nine or more is considered a positive score for sleepiness.
STOP is a simple screening tool to detect sleep apnea. STOP stand for:
Do you Snore?
Do you feel Tired, fatigued or sleepy during the day?
Has anyone Observed you stop breathing in your sleep?
Do you have high blood Pressure?
If the patient answers "yes" to two of the four questions, there is a 77 per cent chance that the person has apnea.
If the person has a positive STOP screen, consider the additional mnemonic BANG. It stands for:
Age: > 50 years
Neck circumference: > 40 cm
The sensitivity of the STOP and BANG screening questions:
- for mild sleep apnea: 84%
- for moderate sleep apnea: 97%
- for severe sleep apnea: 100%