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Home , Bruxism, Catathrenia, Confusional arousals, Exploding head syndrome, Hypnopompic, Night terror

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Parasomnias occurring in sleep–wake transition may toms and autonomic disturbance in persist in children with learning difficul- terrors. Duration can be from a few ties and occasionally into minutes to an hour (sleep ). Sleep

Zenobia Zaiwalla FRCP FRCPCH, Consultant and young adult life in neurologically terrors tend to appear around 18 months Neurophysiologist, Park Hospital for Children normal children. Though benign and of age, with sleep walking a little later and Radcliffe Infirmary, Oxford never associated with significant , in the pre-school and school-age years. the noise disturbs the family and can be NREM often disap- Clin Med 2005;5:109–12 socially embarrassing to the older child. pear by adolescence, but can persist or There is varying of the behav- appear for the first time in adolescence iour, with some acknowledging that the or adulthood. The prevalence of sleep Parasomnias are disorders of experience movements are pleasurable and help walking falls from 15% in childhood to and behaviour, sometimes with promi- overcome associated with sleep less than 1% in adults.3 A recent single nent autonomic features, occurring onset , while others appear gen- photon emission computed tomography during sleep. The sleep behaviours may uinely unaware. In the younger child, study performed during an episode of be mild and self-limiting, but in a few reassurance may be sufficient. There are sleep walking4 revealed activation of cases the potential for injury makes anecdotal reports of positive response to motor regions of the with deactiva- imperative early diagnosis and interven- a metronome in the room set at the tion of association cortices, in keeping tion. Sleep-related epileptic , movement frequency, changing to a with the apparent dissociation of motor though facilitated by sleep, are usually water , , and arousal from sleep during this not classified as parasomnias. The use of . . International Classification of Sleep 1 Disorders (ICSD) subdivides the para- Non-rapid movement Pathophysiology somnias on the basis of their timing in arousal disorders the sleep as follows (Table 1): There is a multifactorial pathophysiology. • sleep–wake transition disorders NREM arousal disorders occur on abrupt Sleep walking is at least 10 times greater • non-rapid (NREM) arousal from NREM sleep, usually deep in first-degree relatives of those who have sleep arousal disorders (slow-wave) sleep, including NREM experienced sleep walking than in the stages 3 and 4, most commonly in the general population, while a population- parasomnias associated with rapid • first part of the night. They include con- based study5 suggests a genetic con- eye movement (REM) sleep fusional , night terrors and sleep tribution in more than a third of adult • other parasomnias. walking. The complexity of the behav- sleep walkers and more than half of chil- Knowledge of the sleep stage asso- iours varies from mild disorientation in dren. Neurophysiological studies suggest ciation of the parasomnias provides a time and space in to inheritance of NREM sleep instability useful approach to diagnosis (Table 2).2 complex semidirected behaviours of sleep with high level of arousal oscillations,6 walking or prominent affective symp- suggested by some to reflect instability of Sleep–wake transition disorders Parasomnias occurring in the sleep–wake Key Points transition state are usually benign, though they can be distressing. Parasomnias are complex experiences and behaviours occurring from sleep Hypnic body jerks occurring towards are a common physiological Most parasomnias are benign though distressing, but some have potential for event. In the , injury to self and others patients report sudden sensations of The characteristics of parasomnias depend on the sleep stage from which they flashing lights and/or loud banging occur noises in the transition between wake- fulness and sleep. These occur especially includes sleep-related epileptic seizures, especially frontal/temporal lobe during periods of emotional from exaggeration of sensory experience as Chronic rapid eye movement (REM) sleep behaviour disorder in adults is often a decreases. Reassurance is precursor of neurodegenerative disorders including Parkinson’s disease usually sufficient. Understanding the complexity and range of behaviours especially in non-REM arousal parasomnias and their genetic, psychological and environmental triggers Rhythmic movement disorders is important for forensic medicine

Rhythmic movement disorders, includ- KEY WORDS: disorders, night terrors, NREM arousals, attacks, REM ing head banging and body rocking, behaviour, sleep walking

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Table 1. International Classification of Sleep Disorders.

Sleep–wake transition disorders NREM arousal disorders REM sleep parasomnias Others

Restless leg syndrome Confusional arousals Sleep Sleep starts Night terrors Sleep Sleep Exploding head syndrome Sleep walking Impaired/painful sleep-related Sleep-related abnormal swallowing syndrome Nocturnal leg cramps REM sleep-related sinus arrest Benign neonatal sleep Rhythmic movement disorders REM sleep behaviour disorder Sleep-related panic attacks Sleep talking Hypnagogic/ Sleep-related episodes Sleep-related laryngospasm Nocturnal groaning Periodic leg movements in sleep

NREM = non-rapid eye movement; REM = rapid eye movement.

levels affecting smooth transi- will be indicated. There has been consid- the literature on violence during sleep tion through various sleep stages. erable recent interest in the forensic walking, Rosalind Cartwright9 proposed Environmental triggers are also impor- consequence of sleep-related behaviours, a standard protocol in assessing forensic tant, including febrile illness, sleep including driving, personal injury, cases which, in addition to clinical/ deprivation, obstructive sleep apnoea, inappropriate sexual behaviour and psychiatric history, should include: , and psychotropic homicide. NREM sleep-related violent • childhood/family history of NREM drugs, , emotional stress and behaviours often show combined fea- parasomnias . tures of and sleep walking. • three of sleep recording, with Psychiatric disorders were identified in a one night preceded by 36 hours of Diagnosis third of adult onset episodes of violence to induce an 7 from sleep, with persistence of sleep episode in the sleep laboratory. Diagnosis of NREM arousal parasomnias walking associated with high scores on Sleep studies may also be necessary is usually clinical, but in some situations hysteria, anxiety and externally directed when the parasomnia behaviour is diffi- video/EEG/ studies hostility scales.8 Following a review of cult to differentiate from sleep-related epileptic seizures,10 especially frequent Table 2. Sleep time and sleep stage linkage to parasomnias (modified from Ref 2). brief nocturnal frontal/ temporal lobe Time and sleep stage Sleep stage Parasomnia seizures. Table 3 outlines the electro- clinical features that can aid differential Pre-sleep Restless leg syndrome diagnosis. Sleep onset NREM stages 1–2 Hypnic jerks Hypnagogic hallucinations Head banging (rhythmic movement disorders) Treatment Bruxism Exploding head syndrome Treatment of arousal parasomnias can be Night groaning challenging. Advice on common Panic attacks/choking episodes from sleep measures to reduce risk of injury during Sleep talking sleep walking behaviours is important, First third of sleep NREM stages 3–4 (all sleep stages) for example: Confusional arousals Sleep walking • locking windows and doors Night terrors • avoiding triggers like alcohol and Middle and late sleep REM sleep Nightmares sleep deprivation Cluster treating obstructive sleep apnoea Painful nocturnal erections • and periodic leg movements REM behaviour disorder Late sleep, early morning NREM or REM sleep Hypnopompic hallucinations (REM sleep) (essential where present). Arousal Sleep drunkenness Psychopathology is present in about (REM sleep; can also occur half the adults with persistent arousal at sleep onset) parasomnias, and -oriented NREM = non-rapid eye movement; REM = rapid eye movement. psychotherapy is advocated. There is no obvious psychopathology in the others

110 Clinical Medicine Vol 5 No 2 March/April 2005 CME Sleep but they are often people who control These patients typically wake 2–3 disorders. In addition to psychotherapy their during the day; obtaining hours after sleep onset, with ‘out of con- for anxiety/stress and daytime eating a handle on unresolved issues main- trol’ food ingestion, becoming agitated patterns, patients may respond to clonez- taining their sleep behaviour can be chal- and angry if resisted. Both types occur on apam, alone or combined with dopamin- lenging for the therapist. Hypnosis has arousal from NREM sleep, with compul- ergic agents, and selective serotonin been tried with varying success.11 The sive food-seeking; they are probably re-uptake inhibitors. anticipatory waking technique described manifestations of a single disorder13 and 12 by Lask can be valuable in children in are associated with a high incidence of Parasomnias associated with whom the parasomnias usually occur psychiatric disorders and psychotropic before parental . Patients at risk drug use. A quarter of cases develop this of injury or harm may need long-term parasomnia for the first time in adult life, REM sleep parasomnias such as sleep treatment with a low dose of with no history of childhood sleep paralysis and hypnogogic hallucinations at night.7,9 walking7 and often associated with day- are classically seen in but may time dieting because of . occur in isolation, as in familial sleep Sleep-related eating disorders paralysis or when there is rebound Treatment increase in REM sleep, for example Eating disorders related to sleep deserve following abrupt withdrawal of alcohol a special mention. Early literature Treatment of sleep-related eating disor- or of or psychotrophic drugs, with differentiated: ders overlaps with management of sleep mental stress or sleep deprivation. • nocturnal eating syndrome, when walking behaviour. Triggers for confu- there is full awareness of eating on sional arousals from NREM sleep such as Rapid eye movement sleep waking and periodic leg movements in sleep and behaviour disorder • sleep-related , when obstructive sleep apnoea as well as night eating occurs in a state of sleep / psychotropic drugs (, The condition of REM sleep behaviour with only partial or no risperidone, olanzapine) have been disorder (RSBD)14 is characterised by vio- awareness. incriminated in sleep-related eating lent/injurious behaviours from attempted

Table 3. Characteristics of frontal/temporal epileptic seizures versus parasomnias.

Epilepsies Parasomnias

NREM arousal REM behaviour Temporal lobe disorder disorder

Time of night Any time Any time 1st third Mid-third or later Duration <1 min Minutes Minutes to 1 hour Minutes Frequency Very frequent (20–30 per night) Few More than 1 uncommon Recur through REM sleep blocks Semiology Stereotype complex motor Confused stereotype Confused, Complex movements and vocalisation automatisms semipurposeful enactment behaviours varying automatisms Directed behaviour/ No No Can occur Can occur violence Resistive Too brief to cause significant Yes, especially postictal Yes Yes injury to others of event Absent Absent Absent Can relate to dream content Family history Sometimes Rarely Common Rarely Polysomnography: sleep NREM stage 2 NREM or REM NREM stages 3–4 REM sleep stage occurrence Arousal immediately leads to Usually an interval Episode immediately Intermittent during REM between arousal and on abrupt arousal sleep with loss of REM seizure atonia EEG Interictal/ictal EEG may be Interictal/ictal No epileptiform activity No epileptiform activity abnormal but can be normal epileptiform change usually present Video Usually diagnostic Usually helpful Helpful May be helpful

NREM = non-rapid eye movement; REM = rapid eye movement.

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dream enactment during REM sleep, sec- as in frontal lobe . The episodes ders: polysomnographic correlates of a ondary to loss of the normal REM sleep occur from NREM stages 2 and 3. heterogeneous syndrome distinct from atonia. The disorder shows a male pre- Differential diagnosis includes night daytime eating disorders. Sleep 1991;14: 419–31. ponderance with a mean age of onset in terrors and arousals from obstructive 8 Ohayon MM, Guilleminault C, Priest RG. various series of 52–62 years, patients sleep apnoea. Night terrors, , and confusional reporting a change in dream character to The sleep choking syndrome – repeated arousals in the general population: their fre- more vivid, violent out of char- episodes of waking through the night quency and relationship to other sleep and acter with their daytime personality. with choking sensation, often in those mental disorders. J Clin 1999;60: 268–76. Acute transient RSBD can occur with with anxious personality – has overlap- 9 Cartwright R. Sleepwalking violence: a sleep stress or rapid withdrawal of alcohol, ping symptoms with panic attacks and disorder, a legal dilemma, and a psycholog- drugs like selective serotonin reuptake may be the same disorder. ical challenge. Review. Am J Psychiatry 2004; inhibitors, tricyclics and . A In sleep-related laryngospasm, on 161:1149–58. proportion of older chronic RSBD waking there is inability to breathe and 10 Malow BA. Paroxysmal events in sleep. Review. J Clin Neurophysiol 2002;19:522–34. patients were thought to be idiopathic, stridor, the episodes occurring infre- 11 Hurwitz TD, Mahowald MW, Schenck CH, but increasingly the view is that RSBD is quently (ca 2–3 times a year). A 24-hour Schluter JL, Bundlie SR. A retrospective out- almost always a precursor of a neurode- ECG recording may be necessary to come study and review of hypnosis as treat- generative disorder such as Parkinson’s exclude REM sleep-related sinus arrest ment of adults with sleepwalking and sleep disease and multisystem . Rarely, when patients can wake abruptly with terror. J Nerv Ment Dis 1991;179:228–33. 12 Lask B. Novel and non-toxic treatment for RSBD may occur in children with disor- vague light headedness or faintness. night terrors. BMJ 1988;297:592. ders involving structures. 13 Winkelman JW. Clinical and polysomno- RSBD in the neurologically normal young Conclusions graphic features of sleep-related eating dis- patient should point to idiopathic overlap order. J Clin Psychiatry 1998;59:14–9. disorder with co-occurrence of NREM Parasomnias are a fascinating group of 14 Schenck CH, Bundlie SR, Ettinger MG, Mahowald MW. Chronic behavioral disor- 15 arousal parasomnia and RSBD. disorders of varying clinical significance ders of REM sleep: a new category of which can challenge clinical skills. They parasomnia. Sleep 1986;9:293–308. 15 Schenck CH, Mahowald MW. REM sleep Diagnosis and treatment open a window to the understanding of the process of both normal and behavior disorder: clinical, developmental, Polysomnography studies with multiple abnormal sleep and overlap a number of and perspectives 16 years after its formal identification in SLEEP. Sleep EMG channels are essential for diagnosis medical specialties. Awareness of the 2002;25:120–38. to demonstrate the loss of muscle atonia range of behaviours that occur in sleep is 16 Vetrugno R, Provini F, Plazzi G, Vignatelli L and other features, including increase essential to target investigations and to et al. (nocturnal groaning): a both in slow-wave sleep and in periodic consider treatment or reassurance, as new type of parasomnia. 2001; leg movements. Most patients respond to appropriate. 56:681–3. clonazepam. References Other parasomnias 1 American Sleep Disorders Association. A number of parasomnias are classified Parasomnias. The international classification of sleep disorders, revised: diagnostic and under ‘Other parasomnias’ in the current coding manual. Rochester, MN: ASDA, ICSD diagnostic and coding manual. 1997:141–213. This allows some leeway to include newly 2 Parkes JD. The parasomnias. Review. Lancet recognised parasomnias such as cata- 1986;ii:1021–5. threnia (nocturnal expiratory groaning) 3 Kavey NB, Whyte J, Resor SR Jr, Gidro-Frank S. Somnambulism in adults. occurring in NREM stage 2 and REM Neurology 1990;40:749–52. 16 sleep in the second part of the night. 4 Bassetti C, Vella S, Donati F, Wielepp P, Panic attacks occurring only from sleep Weder B. SPECT during sleepwalking. are an under-recognised form of para- Lancet 2000;356:484–5. somnia. These patients have recurrent 5 Hublin C, Kaprio J, Partinen M, Heikkila K, Koskenvuo M. Prevalence and genetics of awakening with panic or , often a sleepwalking: a population-based twin feeling of impending death or of study. Neurology 1997;48:177–81. choking. This is neither preceded by 6 Zucconi M, Ferini-Strambi L. NREM para- remembered dreams nor associated with somnias: arousal disorders and differentia- confused behaviour, as occurs in night tion from nocturnal . Review. Clin Neurophysiol 2000;111 terrors, the patient becoming fully awake (Suppl 2):S129–35. immediately on waking. There is no 7 Schenck CH, Hurwitz TD, Bundlie SR, accompanying stereotype motor activity Mahowald MW. Sleep-related eating disor-

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