A confusional arousal (also known as sleep drunkenness or severe sleep inertia) is

medical condition A disease is a particular abnormal condition that adversely affects the structure or function (biology), function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical condi ...

where a person awakened from

sleep Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain Sensory nervous system, sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with th ...

shows

mental confusion In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion"

for at least several minutes. Complete or partial

amnesia Amnesia is a deficit in memory caused by brain damage or brain diseases,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be temporarily caused by t ...

of the episodes may be present.

Signs and symptoms

Confusional arousals are accompanied by mental confusion and disorientation, relative lack of response to environmental stimuli, and difficulty of awakening the subject. Vocalisation accompanied with coherent speech is common. Patients may appear upset, and some of them become aggressive or agitated. As well as for children, attempting to awaken or console an adult patient may increase agitation. Confusional arousals can occur during or following an arousal of deep sleep (see

slow-wave sleep Slow-wave sleep (SWS), often referred to as deep sleep, is the third stage of non-rapid eye movement sleep (NREM), where electroencephalography activity is characterised by slow delta waves. Slow-wave sleep usually lasts between 70 and 90 mi ...

) and upon an attempt of awakening the subject from sleep in the morning. In children, confusional arousals can often be reproduced artificially by awakening the child during deep sleep. However, it doesn't have any clinical significance without deeper investigation. Children living an episode of confusional arousal typically sit up in bed, whimper, cry, moan, and may utter words like “no” or “go away”. They remain distressed and inconsolable despite all parental efforts. Paradoxically, parental efforts can rather increase agitation of the child. The onset of symptoms is usually within 2 and 3 hours of sleep onset (at the time of transition from

to a lighter sleep stage) and those events can last from 10 to 30 minutes. Patients generally wake up without any recollection of the event. It is necessary to distinguish confusional arousals in adults from children.

Neurological symptomatology

Confusional arousals are associated with behavioural awakening with persistent slow-wave electroencephalographic activity (see

) during Non-rapid eye movement sleep (NREM). It suggests that sensorimotor network is activated while non sensorimotor areas are still "asleep". The altered state of consciousness may be explained by a hypersynchronous delta activity (see

delta wave Delta waves are high amplitude neural oscillations with a frequency between 0.5 and 4 hertz. Delta waves, like other brain waves, can be recorded with electroencephalography (EEG) and are usually associated with the deep stage 3 of NREM slee ...

) in network involving the frontoparietal cortices (suggesting to be "asleep"), and higher frequency activities in sensorimotor, orbitofrontal, and temporal lateral cortices (suggesting an "awakening").

Sleep-related violence and abnormal sexual behaviours

Confusional arousals have often been linked to sleep-related violence (self-injury or injury to the bed partner). The latter highlights important medical and legal issues when such behaviours are suspected and purported to have caused a criminal offense. The first documented case of homicide as a result of confusional arousal was reported in medieval times by the case of the Silesian woodcutter Bernard Schedmaizig. Sleep-related abnormal sexual behaviours (also called sexsomnia or

sleep sex Sexsomnia, also known as sleep sex, is a distinct form of parasomnia, or an abnormal activity that occurs while an individual is asleep. Sexsomnia is characterized by an individual engaging in Human sexual activity, sexual acts while in non-rap ...

) are mainly classified as confusional arousals and more rarely associated to

sleepwalking Sleepwalking, also known as somnambulism or noctambulism, is a phenomenon of combined sleep and wakefulness. It is classified as a sleep disorder belonging to the parasomnia family. It occurs during the slow wave stage of sleep, in a state of ...

(also known as somnambulism). Even if sleep-related violence may occur during an episode of confusional arousal, it remains extremely rare and there is no specific predisposition to aggression during these episodes.

Distinction between sleepwalking and night terrors

Violent behaviours in confusional arousals slightly differ from those in sleepwalking or night terrors. Above all, during an episode of confusional arousal the patient never leaves the bed, unlike sleepwalking. A bed partner or parent who tries to calm or restrain the patient by grabbing him or her may trigger a violent reaction as with sleepwalkers. In case of a confusional arousal triggered by an attempt of awakening the patient, violent behaviours may occur almost spontaneously. Unlike confusional arousals and sleep walking, patients experiencing night terrors seem to react to some type of frightening image. Therefore, the violent reaction may occur if another individual is encountered or is in proximity.

Classification

International Classification of Sleep Disorders (ICSD)

According to the 2nd edition of the

International Classification of Sleep Disorders The International Classification of Sleep Disorders (ICSD) is "a primary diagnostic, epidemiological and coding resource for clinicians and researchers in the field of sleep and sleep medicine". The ICSD was produced by the American Academy of Sle ...

(ICSD-2), confusional arousals are classified in NREM parasomnias embedded in the non-epileptic paroxysmal motor events during sleep, which include (1)

Parasomnia Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Parasomnias are dissocia ...

, (2) Sleep-related movement disorders and (3) Isolated symptoms, apparently normal variants and unresolved issues. NREM parasomnias (or disorders of arousal) also include sleep terrors (see

night terror Night terror, also called sleep terror, is a sleep disorder causing feelings of panic or dread and typically occurring during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep and lasting for 1 to 10 minutes. It can last longe ...

) and

. Confusional arousals are characterised by more or less complex movements without leaving bed with whimpering, sitting up in bed and some articulation without walking or terror. In comparison, of other arousal parasomnias the age onset of sleep walking is generally between 5 and 10 years whereas confusional arousals and sleep terror may occur 3 years earlier. Sleep terrors are mainly characterised by screaming, agitation, flushed face, sweating and only share the inconsolability with confusional arousals. The current 3rd edition of the International Classification of Sleep Disorders (ICSD-3) added the sleep-related eating disorders in the disorders of arousal from NREM sleep.

Diagnostic and Statistical Manual of Mental Disorders (DSM)

Confusional arousals are at the time not considered as a disorder in the current 5th edition of the

Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (''DSM''; latest edition: ''DSM-5-TR'', published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a com ...

(DSM-V). This absence may be explained by the fact that confusional arousals have been understudied by the scientific community.

Diagnosis

The evaluation "should include a comprehensive medical history, a physical, neurological, and developmental examination, and a detailed description of the nocturnal events, sleep-wake schedules, and daytime behaviour”. However, the episodes have a long duration and a low rate of same-night recurrence. Even if

usually follows episodes of confusional arousal, it is not a distinct trait related to severity. A video-polysomnography (see

polysomnography Polysomnography (PSG) is a multi-parameter type of sleep study and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Greek πολύς ('' ...

) might be required if life history is untypical. In case of suspicion parents are encouraged to use infrared camera to record the behaviour of their child during sleep. Association of video recordings of nocturnal episodes with historical features is an important tool for both understanding and correctly diagnosing the disorder differently from other episodes of parasomnia. Confusional arousals as well as arousal parasomnias in general must be distinguished from

epileptic seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

on the basis of clinical and electroencephalographic features (see

electroencephalography Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignal, bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in ...

Management

Children mostly outgrow the condition by late adolescence if not sooner. Management includes mainly non-pharmacological treatments and daily behaviours guidelines, but may include safety measures and/or medications if the patient is in danger from his or her behaviour: * Ensure regular and adequate sleep routines in order to prevent sleep-wake cycle to be disrupted. * Use of safety measures for the patient and family by clearing the bedroom from obstacles, securing the windows, or installing locks or alarms. *Medications are necessary if the patient is in danger from his or her behaviour. In this case,

Imipramine Imipramine, sold under the brand name Tofranil, among others, is a tricyclic antidepressant (TCA) mainly used in the treatment of depression. It is also effective in treating anxiety and panic disorder. Imipramine is taken by mouth. Common s ...

or low-dose

Clonazepam Clonazepam, sold under the brand name Klonopin among others, is a benzodiazepine medication used to prevent and treat anxiety disorders, seizures, bipolar mania, agitation associated with psychosis, obsessive–compulsive disorder (OCD), and ...

is beneficial.

Epidemiology

The current prevalence of confusional arousals varies according to the year and the sample population and is approximately 4% (4.2% in 1999 in UK sample population, 6.1% (15–24 years old), 3.3% (25–34 y.o.) and 2% (35+ y.o.) in 2000 in UK, Germany and Italy sample population, 6.9% in 2010 in Norway sample population with a lifetime prevalence of 18.5%). The current prevalence of confusional arousals in children (3–13 y.o.) is higher and around 17.3%. Confusional arousals without a known cause or associated condition is uncommon (for about 1% of cases ).The contribution of genetics and family link is strong and episodes of confusional arousals can occur in several members of the same family.

Risk factors

Some independent risk factors associated with confusional arousals have been identified. According to studies, they are shift work, hypnagogic hallucinations (also known as

hypnagogia Hypnagogia is the transitional state from wakefulness to sleep, also defined as the waning state of consciousness during the onset of sleep. Its corresponding state is '' hypnopompia'' sleep to wakefulness. Mental phenomena that may occur duri ...

), excessive daytime sleepiness,

insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...

and

hypersomnia Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes (such as seasonal affective disorder) and can cause distress and problems with functioning. In the fifth edition ...

disorder,

circadian rhythm sleep disorder Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep–wake disorders (CRSWD), are a family of sleep disorders that affect the timing of sleep. CRSDs cause a persistent pattern of sleep/wake disturbances that arise eit ...

restless legs syndrome Restless legs syndrome (RLS), also known as Willis–Ekbom disease (WED), is a neurological disorder, usually chronic, that causes an overwhelming urge to move one's legs. There is often an unpleasant feeling in the legs that improves temporaril ...

obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial airway obstruction, obstruction of the respiratory tract#Upper respiratory tract, upper airway lea ...

syndrome (OSAS),

bipolar disorder Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in ...

, daily smoking, and age of 15–24 years. These risk factors of confusional arousals are somehow related to mental disorders and medical conditions and affecting mostly younger subjects regardless of gender. Precipitating factors include

sleep deprivation Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either Chronic (medicine), chronic ...

, use of hypnotics or tranquilisers before bedtime, and sudden awakening from sleep (e.g., telephone ringing, alarm clock). In the ICSD-2 alcohol intake had been considered as a precipitating factor of confusional arousals. In the ICSD-3American Academy of Sleep Medicine. International classification of sleep disorders (ISCD). 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014. the relation between alcohol use and disorder or arousal have been excluded. Moreover, the alcohol blackout has been added as a differential diagnosis. These changes have important implications for forensic cases.

References

{{Reflist Parasomnias Sleep disorders