Sleep and wakefulness: causes, symptoms, diagnosis, treatment

Almost half of the US population suffers from sleep disorders, while chronic lack of sleep leads to emotional disorders, memory problems, impairment of fine motor skills, reduced performance and an increased risk of road traffic 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 - a violation of sleep and keeping sleep or a feeling of poor sleep. PDS is characterized by a tendency to fall asleep in the daytime, i.е. In the waking period is normal. Insomnia and PDS are not independent diseases, but symptoms of various diseases associated with sleep disorders. The term "parasomnia" refers to a number of different conditions that arise in a dream or associated with it.

[1], [2], [3], [4]

Physiology of sleep

There are two phases of sleep: the phase of sleep without rapid eye movements [sleep phase without BDG, also the phase of slow sleep, or NREM (pop rapid eye movements) sleep] and the sleep phase with rapid eye movements (sleep phase with BDG), also the phase of rapid sleep , the phase of paradoxical sleep, or REM (rapid eye movements) of sleep. Both phases are characterized by appropriate physiological changes.

Slow sleep (without BDG) accounts for 75 to 80% of the total sleep time in adults. It consists of four stages according to the increase in the depth of sleep, and the stages are cyclically repeated 4-5 times per night (see Figure 215-1). On the EEG in the first stage there is a diffuse deceleration of electrical activity with the appearance of a 9 (theta) rhythm with a frequency of 4-8 Hz, and in the III and IV stages - 5 (delta) rhythm with a frequency of 1 / 2-2 Hz. Slow, rotational movements of the eyes, which characterize the wakefulness and the beginning of the first stage, disappear in the subsequent stages of sleep. Also, muscle activity decreases. Stages III and IV are stages of deep sleep with a high threshold of awakening; awakened at this stage of sleep, a person characterizes it as a "dream of high quality." After the phase of slow sleep, the phase of fast sleep (with BDG) begins, characterized by fast low-voltage activity on the EEG and muscle atony. The depth and frequency of breathing in this phase of sleep is variable, characterized by dreams.

Individual needs for sleep duration vary widely - from 4 to 10 hours during the day. Newborns spend most of the day in a dream; with age, the total time and depth of sleep tend to decrease, and sleep becomes more intermittent. In old people IV stage of sleep can be absent altogether. Such changes are often accompanied by pathological daytime drowsiness and fatigue with age, but their clinical significance is unclear.

Examination

Anamnesis. It is necessary to evaluate the duration and quality of sleep, in particular, to clarify the time of going to bed, the latency of sleep (the time interval from the moment of bedding to the moment of falling asleep), the time of morning awakening, the number of awakenings per night, the number and duration of episodes of daytime sleep. Maintaining an individual sleep journal allows you to collect more reliable information. It is always necessary to clarify the circumstances before going to bed (in particular, eating food or alcohol, physical or mental activity), and to find out whether any medications have been prescribed (or canceled) the patient, to learn about the patient's attitude to alcohol, caffeine, smoking, the level and duration of exercise before bedtime. Mental symptoms, in particular depression, anxiety, mania and hypomania, should be noted.

It is necessary to clearly share the difficulty of falling asleep and actually disturbing sleep (difficulty in maintaining sleep). Difficulty falling asleep is typical for late sleep syndrome (also sleep delayed sleep phase, delayed sleep phase), chronic psychophysiological insomnia, inadequate sleep hygiene, restless legs syndrome, or phobias in childhood. Difficulty in maintaining sleep usually accompanies the syndrome of early sleep, depression, the syndrome of central sleep apnea, the syndrome of periodic limb movements in a dream or aging.

The severity of pathological daytime sleepiness is characterized by the results of an assessment of situations predisposing to falling asleep. One of the popular situational assessment tools is the Epworth Sleepiness Scale; the sum of 10 points indicates a pathological daytime sleepiness.

You should find out the patient's specific symptoms associated with sleep disorders (eg, snoring, intermittent breathing, other respiratory disorders at night, excessive movements and twitching of the limbs); Perhaps a more accurate description of the patient's nightly symptoms will be given to the spouse or other family members.

It is necessary to know whether there are any medical conditions such as COPD or bronchial asthma, heart failure, hyperthyroidism, gastroesophageal reflux, neurological diseases (in particular motor and degenerative disorders) and any diseases with pain syndrome (eg rheumatoid arthritis) that can to disturb sleep.

[5], [6]

Epoort's Sleepiness Scale

Situation

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

In each situation, the probability of falling asleep is estimated by the patient as "no" - 0, "easy" - 1, "moderate" - 2 or "high" - 3. The sum of points 10 indicates a pathological daytime drowsiness.

Physical examination. The physical examination is aimed primarily at identifying the symptoms characteristic of the obstructive sleep apnea syndrome, in particular obesity with a predominant distribution of adipose tissue in the neck or diaphragm; hypoplasia of the lower jaw and retrognathy; nasal congestion; increased tonsils, tongue, soft palate, hyperplasia of the pharyngeal mucosa. The thorax is examined for kyphoscoliosis and stridorous respiration.

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

Instrumental research. Additional studies are needed when the clinical diagnosis is uncertain or when the effectiveness of the prescribed treatment is unsatisfactory. Patients with obvious problems (for example, with a characteristic habit that is in a stressful situation working on a night shift) do not need additional research.

Polysomnography is indicated for the elimination of such disorders as the obstructive sleep apnea syndrome, narcolepsy or the syndrome of periodic limb movements in sleep. Polysomnography covers monitoring parameters such as EEG, eye movements, heart rate, BH, oxygen saturation, muscle tone and sleep activity. To record abnormal movements during sleep use video recording. Polysomnography in typical cases is performed in sleep laboratories. Equipment for domestic use is still not widely available.

With the help of a multiple sleep latency test (MTLS, to assess daytime sleepiness), the rate of falling asleep is estimated for five times 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 stage of sleep (including the phase of fast sleep) are recorded on the polysomnograph. And in the patient's wakefulness test, on the contrary, they ask not to fall asleep in a quiet room. The wakefulness test, presumably, is a more accurate method of assessing the patient's propensity to fall asleep during the day.

Patients with PDS are additionally examined for kidney, liver and thyroid function.

Treatment of sleep and wakefulness

Specific violations are subject to correction. First of all, it is necessary to ensure proper sleep hygiene, non-observance of which is the cause of sleep disorders, and correction is often the only necessary treatment to eliminate mild sleep disorders.

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

All hypnotic drugs affect GABAergic receptors and prolong the inhibitory effects of GABA. Drugs differ mainly in the duration of the action (half-life) and the time before the onset of therapeutic action. Short-acting drugs are indicated for sleep disorders. Drugs with a longer duration of action are recommended if there are problems with maintaining sleep. The aftereffect of these drugs during the day is easier to tolerate, especially after prolonged admission and elderly persons. If excessive sedation, coordination disorder and other symptoms of aftereffects occur during the day, avoid activities that require attention (for example, driving), reduce the dose of the drug, cancel the drug, or replace it with another one according to the indications. The spectrum of side effects of hypnotics includes amnesia, hallucinations, coordination disorder and falling.

Sleeping pills are prescribed with caution to persons with respiratory failure. It should be remembered that in the elderly, any sleeping pill, even in small doses, can cause dysphoria, agitation or aggravation of delirium and dementia.

Measures to improve sleep

Event	Execution
Regular sleep	Sleeping and especially waking at the same time every day, including weekends. It is not recommended to stay in bed excessively.
Restriction of time of stay in bed	Restriction of the time spent in bed improves sleep. If you can not sleep for 20 minutes, you should get out of bed and come back when sleepiness reappears. Bedding is used only for the purpose - for sleep, but not for reading, eating, watching television programs.
Failure, if possible, from sleep during the day. Exceptions are only permissible for persons working in shifts, elderly and narcolepsy	Sleep during the day aggravates disturbances in night sleep in insomnia sufferers. As a rule, daytime sleep reduces the need for stimulants in people with narcolepsy and improves the efficiency of streets working in shifts. Daytime sleep is preferred at the same time, its duration should not exceed 30 minutes.
Observance of rituals before going to sleep	Execution before going to bed with the usual daily activities - brushing teeth, washing, setting an alarm clock, usually helps to fall asleep.
Providing an external environment that is prone to sleep	The bedroom should be dark, quiet and cool; it should only be used for sleep. The darkness in the room is provided by dense curtains or a special mask, the silence is earplugs for the ears.
Selection of comfortable pillows	For greater comfort, you can put cushions under your knees or under your waist. A large pillow under your knees is recommended in situations where back pain disrupts normal sleep.
Regular exercise	Physical stress is useful for healthy sleep and stress relief, but if you engage in fitness late at night, the effect may be reversed: stimulation of the nervous system interferes with relaxation and falling asleep.
Use of relaxation techniques	Stress and anxiety disturb sleep. Reading or a warm bath before going to bed can help to relax. You can use special methods of relaxation, such as mental representation of visual images, muscle relaxation, breathing exercises. Patients should not follow the time by the clock.
Refusal to take stimulant drugs and diuretics	It is not recommended to drink alcohol or caffeine, smoking, eating caffeine-containing foods (chocolate), taking anorexigens and diuretics shortly before going to bed.
Use of bright light during wakefulness	Light during wakefulness improves the regulation of circadian rhythms

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

Other sedatives. For the induction and maintenance of sleep use a wide range of means that are not classic sleeping pills. Alcohol is popular with alcohol, which is not a good choice, since long-term intake of alcohol in high doses leads to a feeling of "breakdown" after sleep, intermittent sleep with frequent nightly awakenings, drowsiness during the day. In addition, alcohol disturbs breathing in sleep in persons with obstructive sleep apnea syndrome. Some over-the-counter antihistamine drugs (eg, doxylamine, diphenhydramine) also have a hypnotic effect, but their effect is little predictable, with side effects such as residual sedation in the daytime, confusion and systemic anticholinergic effects more common in the elderly.

Recommendations for the use of hypnotics

• Definition of clear indications and treatment goals.
• Assignment of minimum effective doses.
• Limit the duration of treatment to several weeks.
• Selection of individual doses.
• Reducing doses while taking depressants of the central nervous system or alcohol and street diseases of the kidneys and liver.
• Avoiding the use of sleeping pills for people with sleep apnea syndrome, with a history of abuse of sleeping pills and pregnant women.
• Avoid abrupt withdrawal of drugs (instead, a gradual dose reduction).
• Conducting repeated assessments of the effectiveness and safety of treatment.

Low doses of some antidepressants at night can 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 (rarely) or there is depression.

Melatonin is the hormone of the epiphysis, the secretion of which is stimulated by darkness and suppressed by light. Linking to the same-named receptors in the suprachiasmal 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 going to bed) can eliminate sleep disorders associated with shift work, with biorhythms malfunctioning when moving to a different time zone, as well as with blindness, late sleep and late sleep fragmentation in old age. Melatonin should be taken only at the time when endogenous melatonin is secreted, otherwise it can only aggravate sleep disturbances. The effectiveness of melatonin has not been proved yet, and there are experimental data on the negative effect of melatonin on the cardiovascular system. The commercial preparations of melatonin have not been approved by regulatory authorities, therefore, the content of active substance in them and its purity, as well as the therapeutic effects with prolonged use are unknown. It is recommended to use melatonin under the supervision of a doctor.