Sleep and wakefulness disorder: causes, symptoms, diagnosis, treatment

Nearly half of the U.S. population suffers from sleep disorders, and chronic sleep deprivation leads to emotional distress, memory problems, fine motor skills, decreased performance, and an increased risk of motor vehicle injuries. Sleep disorders also contribute to cardiovascular morbidity and mortality.

The most common types of sleep disorders are insomnia and pathological daytime sleepiness (PDS). Insomnia is a disorder of falling asleep and maintaining sleep or a feeling of poor quality sleep. PDS is characterized by a tendency to fall asleep during the daytime, i.e. during the normal period of wakefulness. Insomnia and PDS are not independent diseases, but symptoms of various diseases associated with sleep disorders. The term "parasomnias" refers to a number of different conditions that occur during sleep or are associated with it.

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Physiology of sleep

There are two phases of sleep: non-rapid eye movement sleep [non-REM sleep, also known as slow-wave sleep, or NREM sleep] and rapid eye movement sleep [REM sleep, also known as REM sleep]. Both phases are characterized by corresponding physiological changes.

Non-REM sleep accounts for 75 to 80% of the total sleep time in adults. It consists of four stages of increasing sleep depth, and the stages are repeated cyclically 4 to 5 times per night (see Fig. 215-1). In stage I, the EEG shows a diffuse slowing of electrical activity with the appearance of a 9 (theta) rhythm with a frequency of 4 to 8 Hz, and in stages III and IV, a 5 (delta) rhythm with a frequency of 1/2 to 2 Hz. The slow, rotational eye movements that characterize wakefulness and the beginning of stage I disappear in subsequent stages of sleep. Muscle activity also decreases. Stages III and IV are stages of deep sleep with a high threshold for arousal; a person awakening at this stage of sleep characterizes it as “high-quality sleep.” The slow-wave sleep phase is followed by the REM sleep phase, characterized by rapid low-voltage activity on the EEG and muscle atonia. The depth and frequency of breathing in this phase of sleep are inconsistent, and dreaming is characteristic.

Individual sleep requirements vary widely, from 4 to 10 hours per day. Newborns spend most of the day sleeping; with age, the total time and depth of sleep tend to decrease, and sleep becomes more intermittent. In older people, stage IV sleep may be absent altogether. Such changes are often accompanied by pathological daytime sleepiness and fatigue with age, but their clinical significance is unclear.

Survey

History. It is important to assess the duration and quality of sleep, in particular the time of going to bed, sleep latency (the time from going to bed until falling asleep), time of morning awakening, the number of awakenings during the night, and the number and duration of daytime naps. Keeping a personal sleep log allows for more reliable information to be collected. It is always important to clarify the circumstances before going to bed (in particular, food or alcohol intake, physical or mental activity), as well as to find out whether the patient is on any prescribed (or discontinued) medications, the patient's attitude to alcohol, caffeine, smoking, and the level and duration of physical activity before bed. Psychiatric symptoms, in particular depression, anxiety, mania, and hypomania, should be noted.

It is necessary to clearly distinguish between difficulty falling asleep and sleep disorders proper (difficulty maintaining sleep). Difficulty falling asleep is characteristic of late sleep onset syndrome (also delayed sleep phase syndrome, delayed sleep phase syndrome), chronic psychophysiological insomnia, inadequate sleep hygiene, restless legs syndrome or childhood phobias. Difficulty maintaining sleep usually accompanies early sleep onset syndrome, depression, central sleep apnea syndrome, periodic limb movement syndrome or aging.

The severity of pathological daytime sleepiness is characterized based on the results of assessing situations that predispose to falling asleep. One of the popular situational assessment tools is the Epworth Sleepiness Scale; a score of 10 indicates pathological daytime sleepiness.

The patient should be asked about specific symptoms associated with sleep disturbance (e.g. snoring, shortness of breath, other respiratory disturbances at night, excessive movements and twitching of the limbs); spouses or other family members may be able to provide a more accurate description of the patient's nighttime symptoms.

It is important to know whether there is a history of diseases such as COPD or asthma, heart failure, hyperthyroidism, gastroesophageal reflux, neurological diseases (particularly movement and degenerative disorders) and any diseases with pain syndrome (for example, rheumatoid arthritis) that may interfere with sleep.

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Epworth Sleepiness Scale

Situation

• You sit and read
• You are watching TV
• You are sitting in a public place.
• You are traveling in a car as a passenger for 1 hour.
• You lay down to rest after lunch.
• You are sitting and talking to someone
• You sit quietly after dinner (without alcohol)
• You are sitting in your car, stopped for a few minutes on the road

In each situation, the probability of falling asleep is assessed by the patient as “no” - 0, “mild” - 1, “moderate” - 2, or “high” - 3. A score of 10 indicates pathological daytime sleepiness.

Physical examination. Physical examination is primarily aimed at identifying symptoms characteristic of obstructive sleep apnea syndrome, in particular obesity with predominant distribution of adipose tissue in the neck or diaphragm; hypoplasia of the mandible and retrognathia; nasal congestion; enlargement of the tonsils, tongue, soft palate, hyperplasia of the mucous membrane of the pharynx. The chest is examined for kyphoscoliosis and stridor breathing.

It is necessary to pay attention to the presence of symptoms of right ventricular failure. A thorough neurological examination should be performed.

Instrumental examinations. Additional examinations are necessary when the clinical diagnosis is doubtful or when the effectiveness of the prescribed treatment is unsatisfactory. Patients with obvious problems (e.g. with a characteristic habitus, in a stressful situation, working the night shift) do not require additional examinations.

Polysomnography is indicated to rule out disorders such as obstructive sleep apnea, narcolepsy, or periodic limb movement disorder. Polysomnography involves monitoring parameters such as EEG, eye movements, heart rate, respiratory rate, blood oxygen saturation, muscle tone, and activity during sleep. Video recording is used to record abnormal movements during sleep. Polysomnography is typically performed in sleep laboratories. Equipment for home use is not yet widely available.

The multiple sleep latency test (MSLT, for assessing daytime sleepiness) assesses the rate of sleep onset in five polysomnographic studies separated by two-hour intervals. The patient is placed in a dark room and asked to fall asleep; the process of falling asleep and the stages of sleep (including the REM phase) are recorded on a polysomnograph. In contrast, in the wakefulness test, the patient is asked not to fall asleep in a quiet room. The wakefulness test is presumably a more accurate method of assessing a patient's tendency to fall asleep during the day.

Patients with PDS undergo additional examination of kidney, liver and thyroid function.

Treatment of sleep and wakefulness disorders

Specific disorders are subject to correction. First of all, it is necessary to ensure proper sleep hygiene, failure to observe which is the cause of sleep disorders, and correction is often the only necessary treatment for eliminating mild sleep disorders.

Sleeping pills. General recommendations for the use of sleeping pills are aimed at minimizing abuse, misuse, and addiction.

All hypnotics act on GABAergic receptors and prolong the inhibitory effects of GABA. The drugs differ mainly in the duration of action (half-life) and the time until the onset of therapeutic effect. Short-acting drugs are indicated for sleep disorders. Longer-acting drugs are recommended for problems maintaining sleep. The aftereffects of these drugs during the day are easier to tolerate, especially after prolonged use and in the elderly. If excessive sedation, impaired coordination, or other aftereffect symptoms occur during the daytime while taking hypnotics, avoid activities that require increased attention (e.g., driving), reduce the dose, stop taking the drug, or replace it with another one as indicated. The spectrum of side effects of hypnotics includes amnesia, hallucinations, impaired coordination, and falls.

Sleeping pills should be used with caution in people with respiratory failure. It should be remembered that in the elderly, any sleeping pill, even in small doses, can cause dysphoria, agitation, or worsening of delirium and dementia.

Activities to improve sleep

Event	Execution
Regular sleep schedule	Going to bed and especially waking up at the same time every day, including weekends. It is not recommended to stay in bed for too long.
Limit time spent in bed	Limiting the time spent in bed improves sleep. If you cannot fall asleep within 20 minutes, you should get out of bed and return when you feel sleepy again. The bed is used only for its intended purpose - for sleeping, but not for reading, eating, or watching television.
Avoiding daytime sleep if possible. Exceptions are only allowed for shift workers, the elderly, and those suffering from narcolepsy	Daytime sleep worsens nighttime sleep disturbances in insomniacs. As a rule, daytime sleep reduces the need for stimulants in narcolepsy sufferers and improves the performance of street workers who work shifts. Daytime sleep is preferably taken at the same time, its duration should not exceed 30 minutes.
Observing rituals before going to bed	Performing your usual daily activities before going to bed - brushing your teeth, washing your face, setting an alarm clock - usually helps you fall asleep.
Providing an external environment conducive to sleep	The bedroom should be dark, quiet and cool; it should be used only for sleeping. Darkness in the room is provided by thick curtains or a special mask, silence - by earplugs.
Selection of comfortable pillows	For greater comfort, you can place pillows under your knees or lower back. A large pillow under your knees is recommended in situations where back pain interferes with normal sleep.
Regular exercise	Physical activity is good for healthy sleep and stress relief, but if you exercise late at night, it can have the opposite effect: stimulating the nervous system interferes with relaxation and sleep.
Using relaxation techniques	Stress and anxiety interfere with sleep. Reading or a warm bath before bed can help to relax. Relaxation techniques such as mental imagery, muscle relaxation, and breathing exercises can be used. Patients should not watch the clock.
Avoidance of stimulant drugs and diuretics	It is not recommended to consume alcohol or caffeine, smoke, consume caffeine-containing products (chocolate), take anorexigenic drugs and diuretics shortly before going to bed.
Using bright light while awake	Light during wakefulness improves regulation of circadian rhythms

Long-term use of sleeping pills is not recommended due to the risk of developing tolerance and dependence (withdrawal syndrome), when sudden withdrawal of the drug can provoke insomnia, anxiety, tremors and even epileptic seizures. Such effects are typical for withdrawal of benzodiazepines (in particular, triazolam). To reduce the negative effects associated with withdrawal, it is recommended to prescribe the minimum effective dose for a short time, gradually reducing it before completely withdrawing the drug. The new generation drug of medium duration of action eszopiclone (1-3 mg before bedtime) does not cause addiction and dependence even with long-term use (up to 6 months).

Other sedatives. A wide range of drugs other than classic hypnotics are used to induce and maintain sleep. Alcohol is popular, but it is not a good choice because long-term high-dose alcohol consumption can result in a feeling of being “broken” after sleep, interrupted sleep with frequent nighttime awakenings, and daytime sleepiness. Alcohol also disrupts breathing during sleep in people with obstructive sleep apnea syndrome. Some over-the-counter antihistamines (e.g., doxylamine, diphenhydramine) also have a hypnotic effect, but their action is unpredictable and side effects such as residual daytime sedation, confusion, and systemic anticholinergic effects, which are more common in the elderly, are highly likely.

Recommendations for the use of sleeping pills

• Defining clear indications and treatment goals.
• Prescribing minimal effective doses.
• Limiting the duration of treatment to several weeks.
• Selection of individual doses.
• Dose reduction when taking CNS depressants or alcohol at the same time and in patients with kidney and liver diseases.
• Avoid prescribing hypnotics to individuals with sleep apnea, a history of hypnotic drug abuse, and pregnant women.
• Avoid abrupt discontinuation of medications (instead, gradually reduce the dose).
• Conducting repeated assessments of the effectiveness and safety of treatment.

Low doses of some antidepressants at night may also improve sleep: for example, doxepin 25-50 mg, trazodone 50 mg, trimipramine 75-200 mg, and paroxetine 5-20 mg. However, they are used mainly when standard sleeping pills are poorly tolerated (rare) or when depression is present.

Melatonin is a pineal gland hormone, the secretion of which is stimulated by darkness and suppressed by light. By binding to the receptors of the same name in the suprachiasmatic nucleus of the hypothalamus, melatonin indirectly affects the circadian rhythm, especially in the initial stages of physiological sleep. Taking melatonin (usually 0.5-5 mg orally before bedtime) can eliminate sleep disorders associated with shift work, with biorhythm failure when moving to another time zone, as well as with blindness, late sleep syndrome and sleep fragmentation in old age. Melatonin should be taken only at the time when endogenous melatonin is secreted, otherwise it can only worsen sleep disorders. The effectiveness of melatonin has not yet been proven, although there is experimental data on the negative effect of melatonin on the cardiovascular system. Commercially available melatonin products have not been approved by regulatory authorities, so their active substance content and purity, as well as therapeutic effects with long-term use, are unknown. It is recommended to use melatonin under the supervision of a physician.