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ChristerHublin

Episodic Symptoms Associated with Sleep

Essentials

  • Clinically significant symptoms during sleep affect at least 10% of the general population. In adulthood, a great variety of aetiologies may be behind symptoms that arise during sleep.
  • The majority of cases can be diagnosed on the history alone without the need for further investigations. For example, if sleepwalking (somnambulism) has continued since childhood and the clinical picture has not substantially changed over the years, no further investigations are indicated.
  • An eye witness account is essential, particularly in cases where the patient either is not aware or is only partially aware of the events.
  • The assessment of symptoms is important since some of them may be associated with various risks and others warrant further investigations.
  • Should the symptoms recur frequently, or be otherwise distressing, and require medication or other forms of treatment, it is recommended that expertise in the field of sleep medicine is sought.

Symptoms and diagnosis

  • Presentation: motor activity, vocalisations, reactive to speech, stereotyped symptoms?
  • Subjective observations: awareness of events, preceding dreams, recall of events in the morning?
  • Timing: do symptoms occur at sleep onset, during sleep (how many hours after sleep onset) or during arousal from sleep, and the duration of symptoms?
  • Predisposing and preventative factors
  • In parasomnias, family history and symptoms in childhood
  • Further investigations should be considered (video telemetry and polysomnography in a specialist unit) if the episodes
    • involve violence and/or result in an injury
    • cause considerable disturbance to the surroundings
    • occur frequently leading to fatigue during the waking state
    • are clinically atypical
    • arouse a suspicion of an epileptic origin.

Parasomnias

  • Special disorders that occur in association with sleep and involve changes in the sensory, motor and/or autonomic functioning. Some are strongly associated with a certain sleep stage or sleep stage transition phase.
  • The principal pathophysiological mechanism is a dissociation of the consciousness state: the brain is adequately awake to carry out certain motor and/or verbal functions, but sufficiently asleep so that the functions are not conscious and planned.
  • Many parasomnias are well known (e.g. sleepwalking and nightmares), particularly when encountered in close or more distant family members. They are often present as a combination or mixture of parasomnias.
  • Factors which contribute towards deepening or fragmenting sleep enhance symptom development. Should elaborate motor functioning be present or the patient leave the bed, precautions in order to minimise the risk of injuries should be considered:
    • Lock the doors and windows
    • Fit a barrier to stairways
    • Locate the bedroom on the ground floor
    • Attach a cowbell to the bedroom door
    • Remove sharp objects and other potentially dangerous objects from view etc.
  • There is no standardised pharmaceutical therapy: the most often used drugs are those that suppress deep and/or REM (rapid eye movement) sleep (tricyclic antidepressants and benzodiazepines, lately also SSRIs, such as paroxetine), but their effect varies and long treatment periods are not recommended.

Arousal disorders

  • Occur during the first third of the sleep period and arise from deep sleep. The disorder is characterised by a partial and incomplete arousal, the patient reacts slowly and in a confused manner, sometimes even with aggression, for example to attempts to wake him/her up. The patient cannot clearly recall the event, and the episodes are not associated with dreams.
  • The prevalence in adulthood is a few per cent.
  • Confusional arousal (sleep drunkenness)
    • There is no impression of terror and the patient stays in bed.
    • Abnormal use of objects (e.g. talking to the alarm clock as if it were a telephone), vocalisations and bizarre speech may occur.
    • An episode typically lasts for a few minutes.
  • Sleepwalking
    • Motor functioning ranges from getting out of bed to considerably long walks during which the patient might, for example, become locked out of the house.
    • Fumbling with various objects is often evident, and in some cases the patient may also attempt to eat or prepare food or even drive a car.
    • Due to the altered consciousness the patient is clumsy and the risk of injury is significant.
    • An episode of sleepwalking usually lasts less than 15 minutes, and at the end the patient may return to bed. The patient may recall isolated events that took place towards the end of the episode.
  • Night terror (sleep terror)
    • A characteristic feature is intense activation: an episode often starts with an agitated cry, the patient sits upright in bed and appears to be seized by terror.
    • Autonomic hyperactivity is evident: the heart rate and respiration rate increase, pupils dilate and there may be profuse sweating. Symptoms may also include motor activity.
    • An episode usually lasts from 30 seconds to five minutes, after which the patient falls back asleep.

Sleep-wake transition disorders

  • Sudden jerking movements and sensory experiences at sleep onset are manifold. Sudden short myoclonic muscle twitches of the limbs are very common (in 60-70% of the general population).
  • A sensation of falling, heat, itching or a noise in the head may also be present, or the patient may experience a painless explosion or a flash or a brief hallucinatory dream.
  • Stress, excessive exercise and a large caffeine intake may predispose to symptoms. In some cases, symptoms recurring nightly may lead to the fear of sleep onset or sleep deprivation, and the jerks may be painful.
  • Sleep talking is usually a brief episode and void of strong emotion, sometimes it consists only of incoherent vocalisations but may also occur as nightly lengthy and intense monologues. Occurrence is often periodic and common also in adults.

REM parasomnias

Nightmares

  • Distressing or "bad" dreams, which usually wake the person up. The dream is associated with gradually intensifying emotions, usually fear, sometimes sorrow or hatred.
  • Usually there is no screaming or leaving the bed, and the level of consciousness is normal upon awakening in contrast with arousal disorders and REM behaviour disorders.
  • Encountered in about one fifth of the adult population at least from time to time.
  • Incidence increases with some medication (levodopa, some beta blockers as well as antipsychotics and hypnotics) and during alcohol withdrawal.

Post-traumatic stress disorder nightmares

  • The patient repeatedly re-experiences the same threatening event during the night.
  • The symptoms often have similarities with a night terror episode (occurs at the early part of the sleep period, confusion, partial amnesia or signs of strong autonomic activation); may represent an intermediate stage between a nightmare and a night terror attack. Prazosin (e.g. 1-6 mg in the evening) alleviates the symptom in some patients, but the evidence on its effect is inconsistent.

Sleep paralysis

  • A phenomenon lasting no longer than a few minutes, experienced either at sleep onset or upon awakening and usually associated with a fear response, during which the patient is not able to voluntarily move the limbs, body or head. In contrast, eye movements and respiratory muscles function normally.
  • The ability to function normally is restored either spontaneously or through an external stimulus.
  • One quarter to half of otherwise healthy people have experienced an isolated episode of sleep paralysis. It is most common in youth and early adulthood. Predisposing factors may include an irregular sleep-wake rhythm, sleep deficit and stress.
  • An X-linked dominant inherited form is very rare, but in these cases the patient may experience frequent episodes of sleep paralysis in the similar manner as seen in some cases of narcolepsy Narcolepsy and other Hypersomnias of Central Origin.

REM sleep behaviour disorder (RBD)

  • The characteristic feature is diminished or absent muscle atonia (diminished muscle tone) leading to preserved ability to move during a dream.
  • Symptoms are usually associated with a repeated violent dream where, for example, the person is attacked by an animal or a stranger. The motor activity reflects the fleeing or defending of the dreamer and may target the bed partner, who is perceived as the persecutor.
  • Hitting, kicking and jumping out of bed are common and may lead to an injury. The patient does not usually wake up spontaneously but does, for example, to the shout of the bed partner.
  • Estimated incidence is 0.5%, markedly more common in men. The clinical picture is usually chronic and progressive.
  • The disorder is idiopathic in two thirds of cases and the usual age at onset is over 60 years.
  • Often associated with various central nervous system diseases (inflammations, circulatory disturbances, injuries, tumours, dementia-inducing diseases etc.) and may precede classic Parkinson's disease Parkinson's Disease by several years.
  • Anticholinergics, tricyclic antidepressants, other SSRIs and MAO inhibitors as well as alcohol withdrawal may provoke the disorder.
  • Clonazepam and melatonin are effective treatments in the majority of cases.
  • Even where the clinical picture is typical, the diagnosis should be confirmed in specialist health care.

Other parasomnias

  • Bruxism: a stereotyped movement characterized by grinding or clenching of the teeth during sleep.
    • Encountered in about one fifth of adults.
    • Common in masticatory system disorders (enamel damage, painful disorders of the face and head etc.); stress increases symptoms.
    • An occlusal splint (to protect the teeth) is the principal treatment option.
  • Nocturnal bedwetting (enuresis nocturna): rare in adults and in most cases associated with an organic cause.
  • Catathrenia: the principal symptom is repeated sleep-related groaning that occurs night after night.
    • The monotonic sound, arising from central sleep apnoea, lasts for 5-50 seconds and is repeated over several minutes, even up to one hour, usually during the second half of the sleep period.
    • Often starts in childhood and is chronic. The person producing the sound is not aware of it, and catathrenia alone does not affect the person's daytime wellbeing.
  • Nocturnal sleep-related eating disorders: several types exist
    • The clinical picture, which is classified as a parasomnia, often has origins similar to those of sleepwalking.
    • In some cases the disorder is associated with other sleep disorders (e.g. narcolepsy Narcolepsy and other Hypersomnias of Central Origin or restless legs syndrome Restless Legs and Akathisia), whilst in some cases a triggering factor can be identified (changes in medication or the use of stimulants, major life change etc.).
    • Three quarters of patients are women. Among patient series, 10% of those who are obese and 6% of those with insomnia may suffer from this disorder.

Nocturnal epilepsy

  • The pathophysiological mechanism behind parasomnias and epilepsy differ but are closely linked: sleep (lowered consciousness) and sleep deprivation predispose to both conditions, and complex partial seizures may resemble parasomnias.
  • Parasomnias may occasionally lead to epileptic seizures, and an epileptic mechanism may also produce symptoms that resemble parasomnias.
  • In epilepsy, however, seizures normally also occur during the waking state. Most seizures in one quarter of epileptic patients are, nevertheless, associated with sleep.
  • Seizures usually occur either at the beginning or end of a sleep period.
  • Common characteristics:
    • abnormal motor activity (generalised tonic-clonic seizures or focal limb movements)
    • automatisms (lip smacking, fumbling with the bedclothes etc.)
    • urinary incontinence
    • tongue biting
    • a cry at the start of the seizure
    • abnormally heavy breathing
    • postictal confusion.

Paroxysmal dystonias

  • Similar dystonic or dyskinetic limb and head movements occur repeatedly during non-REM sleep but with a varying duration and frequency.
  • The episodes may be brief (15-60 seconds) or longer (up to one hour), and several episodes may occur during one night. An episode is occasionally associated with vocalisations.
  • There is increasing evidence that the origin may be frontal lobe epilepsy. A positive family history of the symptoms is present in some cases.

Functional and psychiatric causes

  • The most common causes are panic attacks and other anxiety states as well as dissociative and conversion disorders.
  • These aetiologies also usually cause symptoms during the waking state.

Features and possible causes of sleep-related disorders

ManifestationPossible causeTypical features
Leaving the bedSleepwalkingEarly part of the night, motor activity usually calm
Sleep behaviour disorderEarly morning hours, motor activity may be dramatic
Complex partial epilepsyEpisodes are usually repeated in a similar fashion
Abnormal movements in bedMuscle twitches and jerksCommon at sleep onset and during the REM stage, particularly at the distal limb parts
Sleep paralysisInability to move skeletal muscles, during sleep onset or arousal from sleep
EpilepsyTonic-clonic seizures, tongue biting
Paroxysmal dystoniasDystonic, ballistic or choreoathetotic movements of varying duration
Disagreeable sensation or an impression of one, abnormal behaviourNightmareMainly in the early morning hours; a dream with an increasingly disagreeable content with subsequent recollection and quick alertness upon arousal
Night terrorEarly night; initially an agitated cry, then the patient sits upright in bed and appears to be seized by terror, not able to make contact
Confusional arousalBizarre behaviour, not able to make contact
Panic attackSudden nocturnal waking up accompanied by fear and an unpleasant feeling as well as various somatic sensations
VocalisationsSleep talkingUsually only sounds or short clips of speech
BruxismGnashing and grinding sound of the teeth
Night terrorEarly night; initially an agitated cry, then the patient sits upright in bed and appears to be seized by terror, not able to make contact
Confusional arousalVocalisations, bizarre behaviour or speech content, not able to make contact
CatathreniaGroaning, usually during the latter half of sleep
EpilepsyA cry at the start of the episode, snoring breathing after the seizure phase, cannot be woken up immediately postictally