Sleep Disorders
Dr. A. S. Minhas MD, FRCPC, Diplomate American Board of Sleep Medicine.
Restless Legs Syndrome
Restless legs syndrome is a disorder characterized by disagreeable leg sensations that usually occur prior to sleep onset and that cause an irresistible urge to move the legs. There is the partial or complete relief of the sensation with leg motion and the return of the symptoms upon cessation of leg movements. The sensations and associated leg movements may interfere with sleep onset and may be present if the person wakes up during the night. The sensations are usually described as aching discomfort, creeping, crawling, pulling, pricking, tingling, or itching etc.
Mostly there is no cause obvious for this condition but occasionally correctable causes are found on investigation.
Good sleep hygiene, exercise, and avoidance of caffeine and other stimulants may help. Medications are very helpful in most cases.
Periodic Limb Movement Disorder
Some people have leg or arm jerk repeatedly during sleep. In the morning they may awake feeling tired and they are sleepy during the day. Often this condition is asymptomatic. About two-third people with restless leg syndrome have this condition. This disorder can be diagnosed in a sleep laboratory. Medications are helpful in most cases.
Narcolepsy
Narcolepsy is a central nervous system disorder due to deficiency of a substance called hypocretin or orexin. This chemical is produced by certain cells in the brain, which are decreased in number in people with narcolepsy.
People with narcolepsy have excessive sleepiness. It is typically associated with cataplexy (muscle weakness with strong emotions such as laughter or anger), sleep paralysis and hypnagogic (at sleep onset) or hypnapompic (at sleep offset) hallucinations.
They need repeated brief naps. The narcoleptic patient typically sleeps for 10 to 20 minutes and awakens refreshed but within the next two to three hours begins to feel sleepy again. Sleep usually occurs in situations in which sleepiness is common: such as traveling in automobile or airplane, meetings, lectures, watching TV or movie, or in theater. The patients may be able to tolerate the sleepiness for a period of time. Eventually, however, it is impossible to combat the recurrent daily sleepiness. There may be sudden and irresistible sleep attacks in situations where sleep normally never occurs, including: during an examination, during conversation and while eating, walking, or driving.
A daytime study called a Multiple Sleep Latency Test (MSLT) can help confirm the presence of narcolepsy. The MSLT should be performed after a night in the sleep lab. The night study documents that there is not another sleep disorder causing your daytime sleepiness. MSLT is performed to examine the severity of daytime sleepiness. MSLT demonstrates that the mean sleep latency (time it takes to fall asleep) is less than 5 to 8 minutes. People with narcolepsy typically enter REM sleep during two or more MSLT naps. An occasional person may need MSLT on 4 separate days to convincingly rule out narcolepsy.
There is treatment available for various symptoms associated with narcolepsy.
Idiopathic Hypersomnia
It is a disorder of central nervous system that is associated with a normal or prolonged nighttime sleep episode and excessive sleepiness consisting of prolonged (1 to 2 hour) daytime naps consisting of NREM sleep. The excessive daytime sleepiness is worsened in situations during which sleepiness is common: after meals (especially lunch), traveling in automobile or airplane, meetings, lectures, watching TV or movie and in theater etc. You may be able to awaken the person normally but some patients report great difficulty waking up and experience disorientation after awakening. Some patients may have sleep attacks like the people with narcolepsy. Naps are usually longer than in narcolepsy or sleep apnea and short naps are generally reported as being non-refreshing. MSLT demonstrates that the mean sleep latency (time it takes to fall asleep) is less than 5 to 8 minutes. People with idiopathic hypersomnia do not enter REM sleep more than once during the MSLT naps.
Sleep Walking
Sleepwalking consists of a series of complex behaviors during slow-wave sleep and result in walking during sleep. Episodes can range from simple sitting up in bed to walking and even to apparent frantic attempts to “escape.” The patient may be difficult to awaken but, when awakened, often is mentally confused. The patient usually has no memory of the episode’s events. Sleepwalking can include inappropriate behavior, such as urinating in a closet, and these behaviors are especially common in children. Sleepwalking can result in falls and injuries. Physical harm can result from the attempt to “escape” or simply from walking into dangerous situations. Rarely, homicide or suicide during apparent sleepwalking episodes has been reported. The person attempting to awaken the patient can be violently attacked.
Sleepwalking is a treatable condition.
Sleep Terrors
These are characterized by a sudden arousal from stage 3 or 4 sleep with a piercing scream or cry, accompanied by intense fear. The person has rapid heartbeat, rapid shallow breathing and sweating. The patient usually sits up in bed, usually cannot be awakened, and, if awakened, is confused and disoriented. Usually there is no memory of the event, although sometimes the patient may report very brief vivid dream images or hallucinations. The episode may be accompanied by incoherent speech or loss of bladder control.
This is a treatable condition.
REM Sleep Behavior Disorder (RBD)
Ordinarily during REM sleep we lose all muscle tone and are unable to move. The people with RBD do not develop this loss of muscle tone and have elaborate motor activity associated with dreams. Punching, kicking, leaping, and running from the bed during attempted dream enactment are frequent manifestations and usually correlate with the reported dream imagery. Medical attention if often sought after injury has occurred to either the person or bed partner. Occasionally, a patient may present because of sleep disruption and excessive daytime sleepiness. Because RBD occurs during REM sleep, it typically appears at least 90 minutes after sleep onset. Violent episodes typically occur about once per week but may appear as frequently as four times per night over several consecutive nights. An acute, temporary form may accompany due to REM sleep rebound during withdrawal from alcohol and sedative-hypnotic agents. Drug-induced cases have been reported during treatment with antidepressants and other medications. There may be a prodromal history of sleep talking, yelling, or limb jerking. Dream content may become more vivid, unpleasant, violent, or action-filled coincident with the onset of this disorder.
The response to treatment is very gratifying for most patients.
Shift Work
Shift work sleep disorder consists of insomnia or excessive sleepiness that occur in relation to work schedules.
The work is usually scheduled during the habitual hours of sleep. The reduction in sleep length usually amounts to one to four. The sleep is unsatisfactory and non-refreshing. Early morning work shifts may also be associated with complaints of difficulty in sleep initiation as well as difficulty in awakening. Work on permanent night shifts can be associated with difficulties initiating sleep.
Excessive sleepiness usually occurs during shifts (mainly night) and is associated with the need to nap and impaired mental ability. Reduced alertness, which occurs not only during the work shift, may be associated with reduced performance, capacity, with consequences for safety.
A major portion of the individual’s free time may have to be used for recovery of sleep, which in many cases will have negative social consequences such as marital problems and impaired social relationship.
A sleep physician can provide helpful suggestions.
Delayed Sleep-Phase Syndrome
About 20% teenagers are affected by this condition and most of them outgrow it. This is a disorder in which the person cannot fall asleep at the desired time, resulting in difficulty in awakening at the desired time. There is little or no difficulty in staying asleep once the sleep has begun. Typically, the patients complain of difficulty in falling asleep until between 2 a.m. and 6 a.m. or difficulty awakening at the desired or necessary time in the morning to fulfill social or occupational obligations. Daytime sleepiness occurs depending on the degree of sleep loss that ensues due to the patient’s attempts to meet his or her social obligations by getting up on time. When not obliged to maintain a strict schedule (e.g. on weekends or during vacations), the patient sleeps normally but at a delayed phase relative to local time.
This is a treatable condition.