EEG and Sleep Disorders

• The dyssomnias are the disorders that produce either difficulty initiating or maintaining sleep or excessive sleepiness.
• This section is divided into three groups of disorders: intrinsic sleep disorders, extrinsic sleep disorders, and circadian rhythm sleep disorders.

Intrinsic Sleep Disorders

• Intrinsic sleep disorders either originate or develop within the body or arise from causes within the body.
• Psychologic and medical disorders producing a primary sleep disorder are listed here.
• Disorders arising within the body that are not primary sleep disorders are listed under Section 3, sleep disorders associated with mental, neurologic, or other medical disorders.

• Psychophysiological insomnia
• Sleep State Misperception
• Idiopathic Insomnia
• Narcolepsy
• Recurrent Hypersomnia
• Idiopathic Hypersomnia
• Posttraumatic Hypersomnia
• Obstructive sleep apnoea syndrome
• Central sleep apnoea syndrome
• Central alveolar hypoventilation syndrome
• Periodic limb movement disorder
• Restless legs syndrome

Extrinsic Sleep Disorders

• Extrinsic sleep disorders either originate or develop from causes outside of the body.
• External factors are integral in producing these disorders.
• Removal of the external factor usually is associated with resolution of the sleep disturbance unless another sleep disorder develops during the course of the sleep disturbance (e.g., psychophysiologic insomnia may follow removal of an external factor responsible for the development of an adjustment sleep disorder).

• Inadequate sleep hygiene
• Environmental sleep disorder
• Altitude insomnia
• Adjustment sleep disorder
• Insufficient sleep syndrome
• Limit-setting sleep disorder
• Sleep-onset association disorder
• Food allergy insomnia
• Nocturnal eating (drinking) syndrome
• Hypnotic-dependent sleep disorder
• Stimulant-dependent sleep disorder
• Alcohol-dependent sleep disorder
• Toxin-induced sleep disorder

Circadian Rhythm Sleep Disorders

• Circadian rhythm sleep disorders are disorders that are related to the timing of sleep within the 24-hour day.
• Some of these disorders are influenced by the timing of the sleep period that is under the individual’s control (e.g., shift work or time-zone change), whereas others are disorders of neurologic mechanisms (e.g., irregular sleep-wake pattern and advanced sleep-phase syndrome).
• Some of these disorders can be present in both an intrinsic and extrinsic form; however, their common linkage through chronobiologic, pathophysiologic mechanisms dictates their recognition as a homogeneous group of disorders.

• Time zone (jet lag) syndrome
• Shift work sleep disorder
• Irregular sleep-wake pattern
• Delayed sleep phase syndrome
• Advanced sleep phase syndrome
• Non 24-hour sleep-wake disorder

• The parasomnias (i.e., the disorders of arousal, partial arousal, and sleep-stage transition) are disorders that intrude into the sleep process and are not primarily disorders of sleep and wake states per se.
• These disorders are manifestations of central nervous system activation, usually transmitted through skeletal muscle or autonomic nervous system channels.
• They are divided into four groups: arousal disorders, sleep-wake transition disorders, parasomnias usually associated with rapid eye movement (REM) sleep, and other parasomnias.

Arousal Disorders

• Arousal disorders are manifestations of partial arousal that occur during sleep.
• These disorders are the “classic” arousal disorders that appear to be primarily disorders of normal arousal mechanisms.
• Examples:
  • Confusional arousals
  • Sleepwalking
  • Sleep terrors

Parasomnias Usually Associated with REM Sleep

• The parasomnias usually associated with REM sleep have their onset during the REM sleep stage; some of these REM sleep parasomnias do occur during other sleep stages, but this occurrence is rare.

• Nightmares
• Sleep paralysis
• Impaired sleep-related penile erections
• Sleep-related painful erections
• REM sleep-related sinus arrest
• REM sleep behaviour disorder

Other Parasomnias

• Other parasomnias are those parasomnias that do not fall into the categories of arousal disorders, sleep-wake transition disorders, or parasomnias associated with REM sleep.

• Sleep bruxism
• Sleep enuresis
• Sleep-related abnormal swallowing syndrome
• Nocturnal paroxysmal dystonia
• Sudden unexplained nocturnal death syndrome
• Primary snoring
• Infant sleep apnoea
• Congenital central hypoventilation syndrome
• Sudden infant death syndrome
• Benign neonatal sleep myoclonus

Characteristic	Nightmare Disorder	Sleep Terror Disorder	REM Sleep Behavior Disorder	Sleepwalking Disorder
Sleep stage	REM	NREM	REM	NREM
Dream recall	Yes	No	Yes	No
Motor activity	No	Screaming, motoric agitation	Yes	Yes
On awakening	Alert	Confused, disoriented	Alert	Confused, disoriented
Time of night	Last third of night	First third of night	Second half of night	First half of night
Prevalence	Children, 20%; adults, 5–10%	Children, 5%; adults, <1%	Unknown	Children, 1–20%; adults, <1%
Autonomic activation	Slight, secondary to fear	Extreme, with sweating and vocalizations	Associated with REM and motor activity	Not present
Danger to self	No	No	Patient acts out dream	Patient walks anywhere

• This section lists those disorders that are not primarily sleep disorders but are mental, neurologic, or other medical disorders that have either sleep disturbance or excessive sleepiness as a major feature of the disorder.
• This listing of mental, neurologic, or other medical disorders is not intended to include all mental and medical disorders that affect sleep or wakefulness.
• It does include, however, those disorders most commonly associated with sleep symptoms.

Associated with Mental Disorders

• Psychoses
• Mood Disorders
• Anxiety Disorders
• Panic Disorder
• Alcoholism

Associated with Neurological Disorders

• Cerebral degenerative disorders
• Dementia
• Parkinsonism
• Fatal Familial Insomnia
• Sleep-related epilepsy
• Electrical status epilepticus of sleep
• Sleep-related headaches

Associated with Other Medical Disorders

• Sleeping Sickness
• Nocturnal cardiac ischaemia
• Chronic obstructive pulmonary disease
• Sleep-related asthma
• Sleep-related gastroesophageal reflux
• Peptic ulcer disease
• Fibrositis syndrome

• This section lists those disorders for which there is insufficient information available to confirm the unequivocal existence of the disorder (e.g., subwakefulness syndrome).
• Most newly described sleep disorders fall under this category until replicated data are available in the literature (e.g., sleep choking syndrome).
• Some sleep disorders that are controversial as to whether they are the extremes of the normal range or represent a definitive disorder of sleep also are included here (e.g., short and long sleepers).

• Short sleeper
• Long sleeper
• Subwakefulness syndrome
• Fragmentary myoclonus
• Sleep hyperhidrosis
• Menstrual-associated sleep disorder
• Pregnancy-associated sleep disorder
• Terrifying Hypnogogic Hallucinations
• Sleep-related neurogenic tachypnea
• Sleep-related laryngospasm
• Sleep choking syndrome

• The predominant complaint is difficulty initiating or maintaining sleep, or non-restorative sleep, for at least 1 month.
• The sleep disturbance (or associated daytime fatigue) causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The sleep disturbance does not occur exclusively during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia.
• The disturbance does not occur exclusively during the course of another mental disorder (eg, major depressive disorder, generalized anxiety disorder, a delirium).

General Considerations

• Transient difficulty sleeping is a vastly more common phenomenon than is chronic insomnia.
• Particularly when the onset of the complaint is coincident with a recent stressful life event, such as bereavement, the short-term administration of mild sedative-hypnotics such as benzodiazepines may be indicated.

The diagnosis of chronic insomnia is based on the subjective complaint of difficulty in initiating or maintaining sleep or of non-restorative sleep (not feeling well-rested after sleep that is apparently adequate in amount) for a duration of 1 month.

Insomnia is more common in women than in men; is more common with age; and is often associated with medical and psychiatric disorders or with abuse of alcohol, drugs, and medications.

• Because chronic insomnia most often occurs as a co-morbid diagnosis with other disorders, the clinician should look carefully for other conditions and treat the primary disorder.
• In fact, primary insomnia in its "pure" form apparently comprises only a very small proportion of the population of patients complaining of difficulty sleeping.

Insomnia Associated with Behavioral or Psychophysiologic Disorders

Acute stress is probably the most common cause of transient and short-term insomnia. These patients may not come to the attention of a clinician because the condition is self-limited and usually resolves without intervention.

Polysomnographic abnormalities have been documented in acute bereavement; however, persistent insomnia over months should raise the consideration of depression, adjustment disorder, and other disorders in the differential diagnosis.

Psycho-physiologic Insomnia

Psychophysiologic insomnia is defined as a "disorder of somatized tension and learned sleep-preventing associations that result in a complaint of insomnia".

All patients with chronic insomnia probably develop some learned sleep-preventing associations, such as marked over concern with their inability to sleep.

The frustration, anger, and anxiety associated with trying to sleep or maintain sleep serve only to arouse them as they try to go to sleep or maintain sleep.

These patients may acquire aversive associations with their bedrooms and often sleep better in other places such as in front of the television set, in a hotel, or in the sleep laboratory.

Insomnia Associated with Sleep-Related Movement Disorders

Restless leg syndrome (RLS) and periodic limb movement of sleep (PLMS) are often discussed together because of the clinical overlap in presentation and symptoms.

RLS has often been described as an uncomfortable "creeping, crawling" sensation or "pins and needles feeling" in the limbs, especially in the lower extremities.

RLS tends to occur during waking and at sleep onset, whereas PLMS occurs during sleep.

Patients with RLS sometimes also have PLMS, but patients with PLMS often do not have RLS.

For most patients with RLS, being recumbent increases the discomfort in the legs and leads to difficulty sleeping.

Further sleep disruption may occur if movement of the affected limb becomes the only way to relieve the dysesthesia.

Patients with RLS or PLMS may present with either of two very different primary complaints: insomnia or hypersomnia.

The movements in PLMS are involuntary, rhythmic, periodic contractions of the anterior tibial muscle with dorsiflexion of the ankle.

The twitches or contractions themselves are about 0.5–5 seconds in duration, usually occurring roughly every 20–40 seconds over periods that can last from minutes to hours.

Each movement may lead to a brief arousal from sleep, although the degree of disruption can vary greatly from patient to patient and even between nights for a given patient.

PLMS may thus provoke tremendous fragmentation of sleep throughout an entire night, a disruption of which the patient is commonly not consciously aware.

The incidence of PLMS increases with advancing age: Patients aged 30–50 years have a slight chance of developing PLMS; the chance increases to 30% over the age of 50 years and to almost 50% over the age of 65 years.

Polysomnographic evaluation confirms and quantifies severity of PLMS and resultant sleep disruption.

Treatment: Gamma amino butyric acid (GABA)-ergic agents (eg, baclofen, carbamazepine, and benzodiazepines, especially clonazepam)

Treatment Approaches

Nonpharmacologic Approaches

• Doctor-Patient Relationship: The doctor-patient relationship is often important not only for its positive benefits but also for preventing secondary complications of insomnia, such as psychological dependence and misuse of hypnotics, alcohol abuse, and circadian disturbances.
• Counselling & Psychotherapy: Some authorities advocate psychotherapy because they believe that insomnia results from anxiety, depression, obsessive rumination, internalization of emotions, and other cognitive and emotional arousal processes.
• Sleep Hygiene: Stimulus-control treatment approaches have been shown in some studies to be effective, usually with young patients who have relatively mild insomnia.

Sleep hygiene

• Keep bedtimes and awakening times constant, even on the weekends.
• Do not use the bed for watching television, reading, or working.
• If sleep does not begin within a period of time, say, 30 minutes, leave the bed and do not return until drowsy.
• Avoid napping.
• Exercise regularly (three to four times per week), but try to avoid exercising in the evening if this tends to interfere with sleep.
• Discontinue or reduce alcohol, caffeine, cigarettes, and other substances that may interfere with sleep.
• Sleep on a comfortable bed.
• Keep room comfortable: temperature, lighting, mosquito, rodents.
• If possible, sleep alone. Avoid snoring partner, avoid partner who engage in midnight calls, etc.

Behavioural & Biofeedback Techniques: These techniques include autogenic training, progressive muscle relaxation, EMG biofeedback, and EEG feedback.

Sleep Restriction Therapy: Because many patients with chronic insomnia both underestimate their actual sleep time and have poor sleep efficiency, it has been proposed that patients limit the time they spend in bed to the estimated duration of total sleep.

• For example, if the patient reports sleeping 6 hours per night, he or she is required to limit time in bed to 6 hours or slightly more. This simple maneuver usually produces mild sleep deprivation, shortens sleep latency, and increases sleep efficiency. As sleep becomes more consolidated, the patient is allowed to gradually increase time in bed.

Pharmacological treatments

• Sedative-Hypnotics
• Sedating Antidepressants

Diagnostic Criteria

• Primary Hypersomnia

• The predominant complaint is excessive sleepiness for at least 1 month (or less if recurrent) as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur almost daily.
• The excessive sleepiness causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The excessive sleepiness is not better accounted for by insomnia and does not occur exclusively during the course of another sleep disorder and cannot be accounted for by an inadequate amount of sleep.
• The disturbance does not occur exclusively during the course of another mental disorder.
• The disturbance is not due to the direct physiological effects of a substance or a general medical condition.

Narcolepsy

• Irresistible attacks of refreshing sleep that occur daily for at least 3 months.
• The presence of one or both of the following:
• cataplexy (i.e., brief episodes of sudden bilateral loss of muscle tone, most often in association with intense emotion)
• Recurrent intrusions of elements of rapid eye movement sleep into the transition between sleep and wakefulness, as manifested by either hypnopompic or hypnagogic hallucinations or sleep paralysis at the beginning or end of sleep episodes
• The disturbance is not due to the direct physiological effects of a substance or another general medical condition.

Narcolepsy is a disorder classically associated with uncontrollable sleep attacks in which the patient abruptly falls asleep in inappropriate (e.g., while eating), embarrassing (e.g., during intercourse), and even dangerous (e.g., while driving) situations. Although sleep attacks have been described as brief (e.g., lasting 15–20 minutes) and refreshing, this is not always true.

Most narcoleptics experience related symptoms, including cataplexy (a sudden loss of muscle tone), hypnagogic hallucinations (dreamlike experiences while falling asleep but not yet asleep), and sleep paralysis (brief paralysis associated with the onset of sleep or wakefulness).

However, only 10–15% of narcoleptic patients will have all four major symptoms (the classic tetrad).

Many narcoleptic patients also report having performed complex behaviors (such as walking from one place to another or writing) without recalling them.

Even in the absence of serious consequences, these symptoms can be frightening for patients and vexing for family members, co-workers, and others. The symptoms can be misinterpreted or misidentified by lay people and unwary clinicians alike. For example, milder episodes of cataplexy (dropping a cup upon hearing a joke) may be attributed to carelessness or clumsiness. Alternatively, a patient may be misdiagnosed as psychotic if his or her doctor mistakenly assumes the hypnagogic hallucinations occur during full wakefulness or have the same significance as waking hallucinations.

Narcolepsy is believed to result from defective REM sleep regulation. Cataplexy and sleep paralysis can be thought of as atonia without REM, whereas hypnagogic hallucinations and sleep attacks have been likened to REM intrusion. Narcolepsy has a prevalence of roughly 0.1%. It generally begins in adolescence and occurs equally in males and females.

Empiric evidence of increased incidence associated with positive family history and histocompatibility locus antigen (HLA)-typing studies are consistent with a genetic contribution. The antigens HLA-DR2 and DQw are highly prevalent in narcolepsy.

Diagnosis of narcolepsy is confirmed in the sleep laboratory by a sleep-onset REM period (on all-night PSG) or a positive multiple sleep latency test (MSLT) (e.g., REM onset during two of the daytime nap opportunities).

Kleine-Levin Syndrome

Recurrent Hypersomnia (Kleine-Levin Syndrome)

Recurrent hypersomnia is characterized by infrequent (usually once or twice a year) episodes of sleeping 18 or more hours per day for at least 3 days at a time. Episodes may also be associated with hyperphagia, hypersexuality, irritability, and confusion, with normal interepisode functioning. It occurs most commonly in adolescent males.

Treatment of hypersomnias

• Treatment of narcolepsy is based on the individual patient's specific target symptoms, the severity of the symptoms, and lifestyle considerations unique to the patient.
• Although some patients with narcolepsy are able to achieve reasonable control of their sleep attacks by structuring their days with scheduled naps, many patients require stimulants (eg, methylphenidate, amphetamines, pemoline) for EDS.

More recently, modafinil has shown considerable promise in preventing sleep attacks and appears to be well tolerated.

Treatment of cataplexy and other cardinal symptoms is based on inhibition of REM sleep by antidepressants such as protriptyline or monoamine oxidase inhibitors.

Treating other causes of hypersomnia tends to be more difficult than managing narcolepsy; however, similar use of stimulants has been partially successful