Shelly K. Weiss
Sleep is one of our basic needs. It is important for our physical, intellectual, and emotional health. Lack of sleep makes us tired and irritable, decreases short-term memory, and can result in mistakes at work and school, as well as sleep-related accidents. Sleep disturbances are common in adolescents. Many young people acknowledge difficulties with sleep (often not obtaining adequate sleep) when specifically asked, although it may not be their chief complaint.
Sleep disorders are classified into four categories—dyssomnias cover a wide range of disorders including difficulty initiating or maintaining sleep, early morning waking (insomnias), and excessive sleepiness; parasomnias are disorders associated with undesirable physical (motor or autonomic) phenomena that occur exclusively or predominantly during sleep; sleep disorders associated with medical/psychiatric disorders, and proposed sleep disorders (Table 24.1) (International Classification of Sleep Disorders [ICSD-R], 2001). Sleep disturbances in adolescents may represent a reaction to anxiety or depression, inadequate sleep due to busy school or work schedules, and drug use (e.g., stimulants, barbiturates, or use of caffeine, nicotine, alcohol, hallucinogens, or other nonprescription substances). In addition, sleep disturbances can be secondary to a specific sleep disorder.
Sleep is divided into rapid eye movement (REM) sleep and nonrapid eye movement (NREM) sleep. Studies of sleep physiology are carried out using polysomnography, which usually includes electroencephalogram (EEG), electrooculogram, electromyogram, and measures of respiratory function such as airflow, oxygen saturation, and end-tidal PCo2 levels.
Rapid Eye Movement Sleep
REM sleep occupies 20% to 30% of sleep time in adolescents and is characterized by a high autonomic arousal state including increased cardiovascular and respiratory activity, very low voluntary muscle tone, and rapid synchronous nonpatterned eye movements. The EEG pattern shows a low-voltage variable frequency resembling the awake state. Most dreams occur during REM sleep.
Nonrapid Eye Movement Sleep
NREM sleep occupies 70% to 80% of sleep time in adolescents and is divided into four stages:
Sleep Pattern and Changes during Adolescence
Normal sleep usually consists of a brief period of stage 1 and stage 2, followed by a lengthier interval of stages 3 and 4. After approximately 70 to 100 minutes of NREM sleep, a 10- to 25-minute REM period occurs. This cycle is repeated four to six times approximately every 90 minutes throughout the night. The REM periods usually increase by 5 to 30 minutes each cycle.
There are developmental changes in sleep patterns that occur between infancy and adulthood. A meta-analysis of age-related changes in objectively recorded sleep patterns reported a decrease in slow-wave sleep of 7% per 5-year period between the ages of 5 and 15 years. There was a concurrent increase in the lighter stage of NREM (stage 2) sleep (Ohayon et al., 2004).
Another documented change in sleep during adolescence is a delay in the circadian timing system. With progressive adolescent development (documented by increasing sexual maturity ratings), there is a tendency for lengthening the internal day. This coupled with the increasing time devoted to academic, employment, social, and extracurricular activities can cause progressive delay in bedtime (Carskadon et al., 1998).
Adolescents require a minimum of 8.5 to 9.5 hours of sleep per night to awake refreshed and rested. A research study has documented that on school nights, 10- to 11-year
olds sleep an average of 9.5 hours, 12- to 13-year-olds sleep 9 hours, 14- to 15-year-olds sleep 7.75 hours, 16- to 17-year-olds sleep 7.5 hours, and 18-year-old college freshmen sleep 7 hours. The adolescent often tries to make up for the sleep deficit accumulated during the week by sleeping much longer on weekends.
Any adolescent with a sleep disturbance should be asked about the following:
A targeted physical examination should be done depending on the particular sleep complaint.
Have an adolescent keep a 1- to 2-week sleep diary, listing bedtimes, nighttime symptoms, time on awakening, daytime fatigue or sleepiness, and daytime naps, can be a very helpful tool in evaluating a sleep disturbance (Fig. 24.1).
Sleep Disorders in Adolescents
In order to appropriately evaluate and manage an adolescent with a sleep disorder, the specific sleep disorder must be determined. Examples of adolescent sleep disorders include the following:
Dyssomnia due to Inadequate Sleep
The most common cause of excessive daytime sleepiness in adolescents (and people of all ages) is inadequate sleep. Inadequate sleep may be due to poor sleeping habits or late bedtimes (often due to busy schedules). Adolescents may have rigorous schedules with academic, employment, and extracurricular activities that result in their having less than the required hours of sleep. In addition, in some school districts, high school starting times are earlier than middle school leaving even less time for sleep. This chronic sleep deprivation may cause complaints of fatigue or difficulty staying awake during school or work, adversely affecting performance. This may result in stimulant use to stay awake, moodiness, and even automobile accidents related to falling asleep at the wheel. Drowsiness or fatigue is associated with >100,000 automobile accidents each year and are especially common in the 16- to 25-year-old driver.
Other causes of inadequate sleep include difficulty falling asleep as a result of stress, anxiety, or depression. Adolescents with depression frequently have sleep onset or sleep maintenance insomnia. Other less common causes of insomnia include any physical illness associated with pain or discomfort and substance abuse or withdrawal (particularly stimulants, alcohol, or sedatives). Medications may
also cause insomnia, including selective serotonin reuptake inhibitors (SSRIs), stimulants, sympathomimetics, and corticosteroids.
FIGURE 24.1 Sleep diary. (From The National Sleep Foundation. 1999 sleep in America poll results. Washington, DC: The National Sleep Foundation, 1999, with permission.)
Dyssomnia due to Delayed Sleep Phase Syndrome
Daytime sleepiness can result from delayed bedtime resulting in extreme difficulty in waking in the morning. Adolescents are particularly prone to this problem because of their busy evening schedules and an intrinsic biological preference for a later bedtime.
A delayed sleep phase syndrome is a circadian phase disorder in which the timing of sleep is delayed. The adolescent has difficulty falling asleep and waking at an expected time; the person tends to fall asleep 3 to 6 hours later than the desired bedtime. If the adolescent is allowed to sleep for a normal length of time, he/she will wake refreshed but will have a difficult time waking for work, school, or social needs because the timing of waking will also be delayed by 3 to 6 hours. If the adolescent is awakened to attend school, he/she may have difficulty arising and may experience daytime sleepiness due to inadequate sleep. If the adolescent is asked to fall asleep at a normal bedtime, he/she will have sleep-onset insomnia.
Dyssomnia due to Obstructive Sleep Apnea Syndrome
The main cause of sleep-disordered breathing (SDB) is obstructive sleep apnea syndrome (OSAS). This is the presence of complete or partial obstruction of the upper airway during sleep and is associated with the following history:
Even if obstructive sleep apnea is present, there may be no abnormalities seen on physical examination. Physical examination may reveal evidence of the following (American Academy of Pediatrics, 2002):
Risk factors include obesity, African-American heritage, and other respiratory factors such as chronic cough, occasional and persistent wheezing, sinus problems, and asthma.
Sleep studies are used to evaluate for apnea (defined as the absence of any effective airflow into the lungs) or hypopneas (defined as incomplete apnea). A sleep study in a person with obstructive sleep apnea demonstrates a pause in breathing, lasting >10 seconds with an associated decrease in oxygen saturation. An apnea-hypopnea index (AHI) divides the number of respiratory events by the estimated sleep time. Different thresholds are used with little consensus. An AHI of 10 is a reasonable cutoff for adolescents.
Narcolepsy is a chronic neurological disorder characterized by two major abnormalities—excessive and over-whelming daytime sleepiness and intrusion of REM sleep phenomenon into wakefulness. The age at onset is usually between 10 and 25 years.
The first and primary manifestation of narcolepsy is excessive daytime sleepiness. The disorder is characterized by the following four classic symptoms:
Frequency of components:
Etiology of Narcolepsy
Narcolepsy is a genetically complex disorder. The close association between narcolepsy–cataplexy and the human leukocyte antigen (HLA) allele DQB1*0602 suggests an autoimmune etiology. Recent studies have identified abnormalities in hypothalamic hypocretin (orexin) neurotransmission (important in regulating the sleep–wake cycle) and in the pathophysiology of narcolepsy (Chabas et al., 2003).
Diagnosis of Narcolepsy
Narcolepsy is diagnosed by history and documentation of objective findings using both overnight polysomnography and daytime multiple sleep latency test (MSLT). The overnight polysomnography will exclude other sleep disorders, such as sleep apnea. The MSLT is the most specific test for narcolepsy. It will show a shortened time to sleep onset (sleep latency) and early onset of REM sleep.
Sleepwalking and Night Terrors (Disorders of Partial Arousal)
Sleepwalking (somnambulism) and night terrors (sleep terrors, pavor nocturnus) are both disorders of impaired and partial arousal from deep slow-wave sleep.
Night terrors (sleep terrors, pavor nocturnus):
Rapid Eye Movement–Related Parasomnia
Although frequently seen in narcolepsy, they can occur in nonnarcoleptics.
Treatment of Sleep Disorders
Preventive counseling can preclude the development of certain sleep disorders that are secondary to poor sleep habits. The sleep-smart tips for teens from the National Sleep Foundation (www.sleepfoundation.org) are useful for adolescents with and without complaints of sleep difficulties.
Sleep-Smart Tips for Teens
Insomnia/Excessive Daytime Sleepiness due to Inadequate Sleep
The treatment of insomnia/excessive daytime sleepiness will differ depending on the cause. Some general management strategies include:
Insomnia due to Delayed Sleep Phase Syndrome
Insomnia due to Obstructive Sleep Apnea Syndrome
The treatment of OSAS requires a team effort. Weight loss, tonsillectomy and adenoidectomy, constant positive airway pressure, and bi-level pressure ventilation are all modalities used to treat SDB. Consultation with pulmonology, a sleep laboratory or center, and head and neck surgery is suggested. A cardiac echocardiogram, looking for pulmonary artery hypertension or right ventricular hypertrophy, and a lateral x-ray of the soft tissues of the neck are useful studies.
Sleep Disorder Clinics
For severe sleep disorders or diagnostic dilemmas, referral to a sleep disorder clinic can help. Appendix II contains a partial list of institutions specializing in the treatment of sleep disorders.
The National Sleep Foundation keeps an updated state-wise list of accredited sleep disorder centers (www.sleepfoundation.org). In addition, clinics in the United States accredited by the American Academy of Sleep Medicine (listed by state) are available at www.aasmnet.org and clinics in Canada (listed by province) are available at www.css.to/sleep/centers.htm.
American Academy of Sleep Medicine
6301 Bandel Road, Suite 101
Rochester, MN 55901; www.asda.org
Canadian Sleep Society
National Center on Sleep Disorders Research
National Heart, Lung, and Blood Institute
National Institutes of Health (NIH)
9000 Rockville Pike, Bldg 31
Bethesda, MD 20892; www.nhlbi.nih.gov/about/ncsdr/index/htm
National Sleep Foundation
1522 K Street, NW, Suite 500
Washington, DC 20005; www.sleepfoundation.org
For Teenagers and Parents
http://www.sleephomepages.org. Sleep Home Pages.
http://www.nhlbi.nih.gov/about/ncsdr/. NIH site about sleep disorders.
http://www.sleepnet.com/disorder.htm. Information about various sleep disorders.
For Health Professionals
http://www.aasmnet.org/. American Academy of Sleep Medicine.
http://www.css.to. Canadian Sleep Society.
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