Hypnic jerk

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Hypnic jerk
Other namesMyoclonic jerk, hypnagogic jerk, sleep start, sleep twitch, night start
Specialty Sleep medicine
CausesRandom involuntary muscle contraction of unknown causation without pathology plus possibly associated with fatigue, sleep deprivation, caffeine, anxiety

A hypnic jerk, hypnagogic jerk, sleep start, sleep twitch, myoclonic jerk, or night start is a brief and sudden involuntary contraction of the muscles of the body which occurs when a person is beginning to fall asleep, often causing the person to jump and awaken suddenly for a moment. Hypnic jerks are one form of involuntary muscle twitches called myoclonus.

Contents

Physically, hypnic jerks resemble the "jump" experienced by a person when startled, sometimes accompanied by a falling sensation. [1] Hypnic jerks are associated with a rapid heartbeat, quickened breathing, sweat, and sometimes "a peculiar sensory feeling of 'shock' or 'falling into the void'". [2] It can also be accompanied by a vivid dream experience or hallucination. [3] A higher occurrence is reported in people with irregular sleep schedules. [4] When they are particularly frequent and severe, hypnic jerks have been reported as a cause of sleep-onset insomnia. [3]

Hypnic jerks are common physiological phenomena. [5] Around 70% of people experience them at least once in their lives with 10% experiencing them daily. [6] [7] They are benign and do not cause any neurological sequelae. [7]

Causes

According to the American Academy of Sleep Medicine (AASM), there is a wide range of potential causes, including anxiety, stimulants like caffeine and nicotine, stress, and strenuous activities in the evening. It also may be facilitated by fatigue or sleep deprivation. [7] However, most hypnic jerks occur essentially at random in healthy people.[ citation needed ] [8] Nevertheless, these repeated, intensifying twitches can cause anxiety in some individuals and a disruption to their sleep onset. [6]

Sometimes, hypnic jerks are mistaken for another form of movement during sleep. For example, hypnic jerks can be confused with restless leg syndrome, periodic limb movement disorder, hypnagogic foot tremor, rhythmic movement disorder, and hereditary or essential startle syndrome, including the hyperplexia syndrome. But some phenomena can help to distinguish hypnic jerk from these other conditions. For example, the occurrence of hypnic jerk arises only at sleep onset and it happens without any rhythmicity or periodicity of the movements and EMG bursts. Also, other pertinent history allows to differentiate it. [6]

This physiological phenomenon can also be mistaken for myoclonic seizure, but it can also be distinguished by different criteria such as the fact that hypnic jerk occurs at sleep onset only or that the EEG is normal and constant. In addition, unlike seizures, there are no tongue bites, urinary incontinence and postictal confusion in hypnic jerk. This phenomenon can therefore be distinguished from other more serious conditions. [6]

Scientists do not know exactly why this phenomenon occurs and are still trying to understand it. None of the several theories that have attempted to explain it has been fully accepted. [9] One hypothesis posits that the hypnic jerk is a form of reflex, initiated in response to normal bodily events during the lead-up to the first stages of sleep, including a decrease in blood pressure and the relaxation of muscle tissue. [10] Another theory postulates that the body mistakes the sense of relaxation that is felt when falling asleep as a sign that the body is falling. As a consequence, it causes a jerk to wake the sleeper up so they can catch themselves. [11] A researcher at the University of Colorado suggested that a hypnic jerk could be "an archaic reflex to the brain's misinterpretation of muscle relaxation with the onset of sleep as a signal that a sleeping primate is falling out of a tree. The reflex may also have had selective value by having the sleeper readjust or review his or her sleeping position in a nest or on a branch in order to assure that a fall did not occur", but evidence is lacking. [2]

During an epilepsy and intensive care study, the lack of a preceding spike discharge measured on an epilepsy monitoring unit, along with the presence only at sleep onset, helped differentiate hypnic jerks from epileptic myoclonus. [12]

According to a study on sleep disturbances in the Journal of Neural Transmission, a hypnic jerk occurs during the non-rapid eye movement sleep cycle and is an "abrupt muscle action flexing movement, generalized or partial and asymmetric, which may cause arousal, with an illusion of falling". [13] Hypnic jerks are more frequent in childhood with 4 to 7 per hour in the age range from 8 to 12 years old, and they decrease toward 1 or 2 per hour by 65 to 80 years old. [13]

Treatment

There are ways to reduce hypnic jerks, including reducing consumption of stimulants such as nicotine or caffeine, avoiding physical exertion prior to sleep, and consuming sufficient magnesium. [14] [15]

Some medication can also help to reduce or eliminate the hypnic jerks. For example, low-dose clonazepam at bedtime may make the twitches disappear over time. [6]

In addition, some people may develop a fixation on these hypnic jerks leading to increased anxiety, worrying about the disruptive experience. This increased anxiety and fatigue increases the likelihood of experiencing these jerks, resulting in a positive feedback loop. [16]

See also

Related Research Articles

Absence seizures are one of several kinds of generalized seizures. In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures ; however, usage of this terminology is no longer recommended. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy. Absence seizures are most common in children. They affect both sides of the brain.

Exploding head syndrome (EHS) is an abnormal sensory perception during sleep in which a person experiences auditory hallucinations that are loud and of short duration when falling asleep or waking up. The noise may be frightening, typically occurs only occasionally, and is not a serious health concern. People may also experience a flash of light. Pain is typically absent.

<span class="mw-page-title-main">Myoclonus</span> Involuntary, irregular muscle twitch

Myoclonus is a brief, involuntary, irregular twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus describes a medical sign and, generally, is not a diagnosis of a disease. It belongs to the hyperkinetic movement disorders, among tremor and chorea for example. These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions or brief lapses of contraction. The most common circumstance under which they occur is while falling asleep. Myoclonic jerks occur in healthy people and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shuddering attacks in babies fall in this category.

Opsoclonus myoclonus syndrome (OMS), also known as opsoclonus-myoclonus-ataxia (OMA), is a rare neurological disorder of unknown cause which appears to be the result of an autoimmune process involving the nervous system. It is an extremely rare condition, affecting as few as 1 in 10,000,000 people per year. It affects 2 to 3% of children with neuroblastoma and has been reported to occur with celiac disease and diseases of neurologic and autonomic dysfunction.

<span class="mw-page-title-main">Hyperkinesia</span> Excessive movements due to basal ganglia dysfunction

Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease.

Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RLS), which is characterized by a voluntary response to an urge to move legs due to discomfort. PLMD on the other hand is involuntary, and the patient is often unaware of these movements altogether. Periodic limb movements (PLMs) occurring during daytime period can be found but are considered as a symptom of RLS; only PLMs during sleep can suggest a diagnosis of PLMD.

<span class="mw-page-title-main">Stiff-person syndrome</span> Human medical condition

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Rhythmic movement disorder (RMD) is a neurological disorder characterized by repetitive movements of large muscle groups immediately before and during sleep often involving the head and neck. It was independently described first in 1905 by Zappert as jactatio capitis nocturna and by Cruchet as rhythmie du sommeil. The majority of RMD episodes occur during NREM sleep, although REM movements have been reported. RMD is often associated with other psychiatric conditions or mental disabilities. The disorder often leads to bodily injury from unwanted movements. Because of these incessant muscle contractions, patients' sleep patterns are often disrupted. It differs from restless legs syndrome in that RMD involves involuntary muscle contractions before and during sleep while restless legs syndrome is the urge to move before sleep. RMD occurs in both males and females, often during early childhood with symptoms diminishing with age. Many affected individuals also have other sleep related disorders, like sleep apnea. The disorder can be differentially diagnosed into small subcategories, including sleep related bruxism, thumb sucking, hypnagogic foot tremor, and rhythmic sucking, to name a few. In order to be considered pathological, the ICSD-II requires that in the sleep-related rhythmic movements should “markedly interfere with normal sleep, cause significant impairment in daytime function, or result in self-inflicted bodily injury that requires medical treatment ”.

<span class="mw-page-title-main">MERRF syndrome</span> Medical condition

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References

  1. ↑ "Brain Basics: Understanding Sleep" (PDF). National Institute of Neurological Disorders and Stroke . National Institutes of Health. 2006. Archived from the original (PDF) on 2019-07-03. Retrieved 2019-07-03. Many also experience sudden muscle contractions called hypnic myoclonia, often preceded by a sensation of starting to fall. These sudden movements are similar to the "jump" we make when startled.
  2. 1 2 Friedman, Lauren F. (2014-05-21). "Why You Sometimes Feel Like You're Falling And Jerk Awake When Trying To Fall Asleep". Business Insider . Retrieved 2016-07-17.
  3. 1 2 Oswald, Ian (1959-03-01). "Sudden Bodily Jerks on Falling Asleep". Brain . 82 (1): 92–103. doi:10.1093/brain/82.1.92. ISSN   0006-8950. PMID   13651496.
  4. ↑ "Basics of Sleep Behavior: NREM and REM Sleep". Sleep Syllabus. Archived from the original on 2011-07-18. Retrieved 2019-07-03. These muscular contractions, called sleep related myoclonias are not pathological events, although they tend to occur more frequently with stress or unusual or irregular sleep schedules.
  5. ↑ Sander, Howard; Geisse, Hildegarde; Quinto, Christine; Sachdeo, Rajesh; Chokroverty, Sudhansu (1998). "Sensory sleep starts". Journal of Neurology, Neurosurgery & Psychiatry. 64 (5): 690. doi:10.1136/jnnp.64.5.690. PMC   2170079 . PMID   9598699.
  6. 1 2 3 4 5 Chokroverty, Sudhansu; Bhat, Sushanth; Gupta, Divya (2013). "Intensified Hypnic Jerks: A Polysomnographic and Polymyographic Analysis". Journal of Clinical Neurophysiology. 30 (4): 403–410. doi:10.1097/WNP.0b013e31829dde98. PMID   23912581. S2CID   38840788.
  7. 1 2 3 Vetrugno, Roberto; Montagna, Pasquale (2011). "Sleep-to-wake transition movement disorders". Sleep Medicine. 12: S11–S16. doi:10.1016/j.sleep.2011.10.005. PMID   22136891.
  8. ↑ Syring, Kaitlyn (2008-02-28). "A case of the jerks". The University Daily Kansan . Archived from the original on 2010-07-26. Retrieved 2019-10-16.
  9. ↑ "Hypnic (Hypnagogic) Jerking Explained – The Comprehensive Guide For 2019". Sleep Advisor. Retrieved 27 June 2019.
  10. ↑ Castro, Joseph (21 November 2017). "Why Do People 'Twitch' When Falling Asleep?". LiveScience .
  11. ↑ "Complete Guide to Hypnic Jerks". Hack to Sleep: a guide to better sleep. 26 March 2019. Retrieved 1 July 2019.
  12. ↑ Bruce J Fisch, MD (23 October 2009). Epilepsy and Intensive Care Monitoring: Principles and Practice. Demos Medical Publishing. ISBN   978-1-935281-59-7.
  13. 1 2 Askenasy, J. J. M. (2003). "Sleep Disturbances in Parkinsonism". Journal of Neural Transmission. 110 (2). Springer-Verlag: 125–50. doi:10.1007/s007020300001. PMID   12589574. S2CID   9147326.
  14. ↑ Sathe, Harshal; Karia, Sagar; Desousa, Avinash; Shah, Nilesh (2015). "Hypnic jerks possibly induced by escitalopram". Journal of Neurosciences in Rural Practice. 6 (3): 423–424. doi: 10.4103/0976-3147.158797 . PMC   4481805 . PMID   26167034.
  15. ↑ Shebak, Shady; Bader, Geoffrey (2015). "Midazolam and Low Magnesium Associated With Myoclonic Jerks: A Case Report". The Primary Care Companion for CNS Disorders. 17 (2): 10.4088/PCC.14l01724. doi:10.4088/PCC.14l01724. PMC   4560178 . PMID   26445681.
  16. ↑ Green, Ethan (April 16, 2013). "Hypnic Jerks: How To Avoid Waking With A Jolt". No Sleepless Nights. Retrieved 3 July 2019.
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