Symptoms include:

- opsoclonus (rapid, involuntary, multivectorial (horizontal and vertical), unpredictable, conjugate fast eye movements without intersaccadic [quick rotation of the eyes] intervals)

- myoclonus (brief, involuntary twitching of a muscle or a group of muscles)

- cerebellar ataxia, both truncal and appendicular

- aphasia (a language disorder in which there is an impairment of speech and of comprehension of speech, caused by brain damage)

- mutism (a language disorder in which a person does not speak despite evidence of speech ability in the past, often part of a larger neurological or psychiatric disorder)

- lethargy

- irritability or malaise

- drooling

- strabismus (a condition in which the eyes are not properly aligned with each other)

- vomiting

- sleep disturbances

About half of all OMS cases occur in association with neuroblastoma (a cancer of the sympathetic nervous system usually occurring in infants and children).

In one of the few reported cases, the subject presented with muscle weakness and fatigue, muscle twitching, excessive sweating and salivation, small joint pain, itching and weight loss. The subject also developed confusional episodes with spatial and temporal disorientation, visual and auditory hallucinations, complex behavior during sleep and progressive nocturnal insomnia associated with diurnal drowsiness. There was also severe constipation, urinary incontinence, and excessive lacrimation. When left alone, the subject would slowly lapse into a stuporous state with dreamlike episodes characterized by complex and quasi-purposeful gestures and movements (enacted dreams). Marked hyperhidrosis and excessive salivation were evident. Neurological examination disclosed diffuse muscle twitching and spontaneous and reflex myoclonus, slight muscle atrophy in the limbs, absence of tendon reflexes in the lower limbs and diffuse erythema especially on the trunk with scratching lesions of the skin.

Compulsive behaviours, stereotypies and reduplicative paramnesias can be part of the CNS spectrum.

In most cases OMS starts with an acute flare-up of physical symptoms within days or weeks, but some less obvious symptoms such as irritability and malaise may begin weeks or months earlier.

In all of the reported cases, the need for sleep was severely reduced and in some cases not necessary. The duration of sleep in one case decreased to about 2–4 hours per 24-hour period. Clinical features pertaining to insomnia include daytime drowsiness associated with a loss of ability to sleep, intermingled with confusional oneiric status, and the emergence of atypical REM sleep from wakefulness. The Polysomnogram (PSG) picture of this disease is characterized by an inability to generate physiological sleep (key features are the suppression of the hallmarks of stage 2 non-REM sleep: spindles and K complexes) and by the emergence of REM sleep without atonia. The involvement of the thalamus and connected limbic structures in the pathology indicate the prominent role that the limbic thalamus plays in the pathophysiology of sleep. In a case documented in 1974, PSG findings documented the sustained absence of all sleep rhythms for up to a period of 4 months.

Electroencephalography (EEG) in one case was dominated by "wakefulness" and “subwakefulness” states alternating or intermingled with short (< 1 min) atypical REM sleep phases, characterized by a loss of muscle atonia. The “subwakefulness” state was characterized by 4–6 Hz theta activity intermingled with fast activity and desynchronized lower voltage theta activity, behaviourally associated with sleep-like somatic and autonomic behavior. The subject was said to suffer from “agrypnia excitata”, which consists of severe total insomnia of long duration associated with decreased vigilance, mental confusion, hallucinations, motor agitation, and complex motor behavior mimicking dreams, and autonomic activation. CNS and autonomic symptoms were caused by impaired corticolimbic control of the subcortical structures regulating the sleep-wake and autonomic functions.

Hyperekplexia ("exaggerated surprise") is a neurologic disorder classically characterised by pronounced startle responses to tactile or acoustic stimuli and hypertonia. The hypertonia may be predominantly truncal, attenuated during sleep and less prominent after a year of age. Classic hyperekplexia is caused by genetic mutations in a number of different genes, all of which play an important role in glycine neurotransmission. Glycine is used by the central nervous system as an inhibitory neurotransmitter. Hyperekplexia is generally classified as a genetic disease, but some disorders can mimic the exaggerated startle of hyperekplexia.

Parasomnia disorders are classified into the following categories:

- arousal disorders

- sleep-wake transition disorders

- parasomnias associated with REM sleep

Satoyoshi syndrome, also known as Komura-Guerri syndrome, is a rare progressive disorder of presumed autoimmune cause, characterized by painful muscle spasms, alopecia, diarrhea, endocrinopathy with amenorrhoea and secondary skeletal abnormalities. The syndrome was first reported in 1967 by Eijiro Satoyoshi and Kaneo Yamada in Tokyo, Japan. To this date, fewer than 50 cases worldwide have been reported for the Satoyoshi syndrome.

People with the syndrome typically develop symptoms of the illness at a young age, usually between the age of six and fifteen years old. The initial symptoms are muscle spasms in the legs and alopecia, also known as baldness. The spasms are painful and progressive and their frequency varies from 1 or 2 to 100 per day, each lasting a few minutes. It can be sufficiently severe to produce abnormal posturing of the affected limbs, particularly the thumbs. With progression the illness involves the pectoral girdle and trunk muscles and finally the masseters and temporal muscles. The spasms usually spare the facial muscles. Severe spasms can interfere with respiration and speech. During an attack-free period, non-stimulus-sensitive myoclonus can occur in the arms, legs and neck. Diarrhea occurs in the first 2–3 years with intolerance to carbohydrate and high glucose diets. Endocrinopathy manifests as amenorrhea and hypoplasia of the uterus. Affected children fail to attain height after 10–12 years of age.

The syndrome is not known to be a primary cause of mortality, but some patients have died as a result of secondary complications, such as respiratory failure and malnourishment.

In one 6-year-old patient antibodies to GABA-producing enzyme glutamate decarboxylase were detected.

The three main signs of hyperekplexia are generalized stiffness, excessive startle beginning at birth and nocturnal myoclonus. Affected individuals are fully conscious during episodes of stiffness, which consist of forced closure of the eyes and an extension of the extremities followed by a period of generalised stiffness and uncontrolled falling at times. Initially, the disease was classified into a "major" and a "minor" form, with the minor form being characterized by an excessive startle reflex, but lacking stiffness. There is only genetic evidence for the existence of the major form.

Other signs and symptoms of hyperekplexia may include episodic neonatal apnea, excessive movement during sleep and the head-retraction reflex. The link to some cases of Sudden Infant Death remains controversial.

Over the past thirty years, several studies have found that those afflicted with NSRED all have different symptoms and behaviors specific to them, yet they also all have similar characteristics that doctors and psychologists have identified to distinguish NSRED from other combinations of sleep and eating disorders such as night eating syndrome. Winkelman says that typical behaviors for patients with NSRED include: "Partial arousals from sleep, usually within 2 to 3 hours of sleep onset, and subsequent ingestion of food in a rapid or 'out of control' manner." They also will attempt to eat bizarre amalgamations of foods and even potentially harmful substances such as glue, wood, or other toxic materials. In addition, Schenck and Mahowald noted that their patients mainly ate sweets, pastas, both hot and cold meals, improper substances such as "raw, frozen, or spoiled foods; salt or sugar sandwiches; buttered cigarettes; and odd mixtures prepared in a blender."

During the handling of this food, patients with NSRED distinguish themselves, as they are usually messy or harmful to themselves. Some eat their food with their bare hands while others attempt to eat it with utensils. This occasionally results in injuries to the person as well as other injuries. After completing their studies, Schenck and Mahowald said, "Injuries resulted from the careless cutting of food or opening of cans; consumption of scalding fluids (coffee) or solids (hot oatmeal); and frenzied running into walls, kitchen counters, and furniture." A few of the more notable symptoms of this disorder include large amounts of weight gain over short periods of time, particularly in women; irritability during the day, due to lack of restful sleep; and vivid dreams at night. It is easily distinguished from regular sleepwalking by the typical behavioral sequence consisting of "rapid, 'automatic' arising from bed, and immediate entry into the kitchen." In addition, throughout all of the studies done, doctors and psychiatrists discovered that these symptoms are invariant across weekdays, weekends, and vacations as well as the eating excursions being erratically spread throughout a sleep cycle. Most people that suffer from this disease retain no control over when they arise and consume food in their sleep. Although some have been able to restrain themselves from indulging in their unconscious appetites, some have not and must turn to alternative methods of stopping this disorder. It is important for trained physicians to recognize these symptoms in their patients as quickly as possible, so those with NSRED may be treated before they injure themselves.

Under DSM-5 criteria, there are 11 diagnostic groups that comprise sleep-wake disorders. These include, Insomnia disorder, Hypersomnolence disorder, Narcolepsy, Obstructive sleep apnea hypopnea, Central sleep apnea, Sleep-related hypoventilation, Circadian rhythm sleep-wake disorders, Non–rapid eye movement (NREM) sleep arousal disorders, Nightmare disorder, Rapid eye movement (REM) sleep behavior disorder, Restless legs syndrome, and substance-medication-induced sleep disorder. Sexsomnia is classified under NREM arousal parasomnia.

Onset of symptoms usually occur in early adulthood and is characterized by intention tremor, progressive ataxia, convulsions, and myoclonic epileptic jerks.

Tremors usually affect one extremity, primarily the upper limb, and eventually involve the entire voluntary motor system. Overall, the lower extremity is usually disturbed less often than the upper extremity.

Additional features of the syndrome include: an unsteady gait, seizures, muscular hypotonia, reduced muscular coordination, asthenia, adiadochokinesia and errors with estimating range, direction, and force of voluntary movements. Mental deterioration can occur, however it is rare.

MRI: medial temporal lobe signal change bilateral hippocampal lesions, with signals that were hypointense in IR sequences and hyperintense in FLAIR.

Age: Children, Young Adult, Elderly

Sex: Both

Onset: Subacute

Clinical features NMDA Ab related patients in adult shows;

- Early features of higher cognitive dysfunction, confusion, behavioural changes, amnesia, dysphasia. Psychiatric: hallucinations, psychotic, agitation, depressive, anxiety, obsessive. Seizures: generalized, complex partial, simple partial.

- Late features: Spontaneous reduction in conscious level, Movement disorder: choreoathetoid (orofacial, upper limbs, lower limbs), parkinsonian, rigidity, myoclonus, oculogyric crises, opisthotonus, startle. Dysautonomia : tachy/brady-cardia, hyperhidrosis, persistent pyrexia, central hypoventilation, labile/high blood pressure, hypersalivation, pseudoobstruction, cardiac asystole.

NMDA Ab related patients in children and adolescent.

Commonly

- Behavioral or personality change, sometimes associated with

- Seizures and

- Sleep dysfunction;

- Severe speech deficits on admission

- Stereotyped movements,

- Autonomic instability

- Hypoventilation

Rarely

- Dyskinesias or dystonia;

Other Cases have similar presentation

- Disorientation,

- Hallucinations

- Confusion

- Memory loss

- Seizures: Partial temporal lobe. Pilomotor Status epilepticus

- Relative absence of cerebellar and brainstem sings

- Post partum psychosis

- Dyskinesias

Recurrent seizures are the most recognizable feature of this syndrome and are most often the first sign of this syndrome. These syndromes are often ongoing and poorly responsive to anti-seizure medications. Most patients develop seizures the first few years of life, but the age of onset ranges from ages 1 to 17. Different types of seizure have been reported in this syndrome. The most common seizure type appears to be brief focal onset epileptic seizures with impairment of consciousness and awareness, known as complex partial seizures. Other features you may see in these complex partial seizures include staring, oral automatisms, unspecified automatic behavior, involuntary motor movements and/or head turning.

Furthermore, many patients have subtle nighttime behavioral changes, such as stretching, rubbing, and turning resembling a nighttime awakening. However, electroencephalography (EEG) studies during these events show abnormal electrical seizure activity, indicating that nocturnal behavioral events are actually subtle nocturnal seizures or non-convulsive status epilepticus. Many of these patients experience their seizures only during sleep. They can have seemingly bizarre features as they originate from the frontal lobe of the brain. Often, individuals with ring chromosome 20 syndrome are initially found to have complex partial seizures of frontal lobe origin, though imaging studies do not show a corresponding structural brain abnormality. In certain patients, these seizures may secondarily generalized.

Individuals from the ages of 0–17 years should be considered for ring 20 chromosome analysis if they have: predominantly complex partial seizures, medically refractory cryptogenic epilepsy, Lennox-Gastaut-like features with no cause identified, frequent subtle nocturnal seizures, an EEG showing prolonged high voltage frontally dominant slowing intermixed with spikes or sharp waves, an EEG showing overlapping features of continuous slow spike and wave discharges in sleep (CSWS) and electrical status epilepticus in sleep (ESES), and/or subsequent cognitive impairment/learning difficulties/mild retardation.These patients will typically have a normal childhood development until onset of epilepsy and lack evidence of dysmorphism or other congenital malformations.

Nocturnal sleep-related eating disorder (NSRED), also known as sleep-related eating disorder (SRED), sleep eating, or somnambulistic eating, is a combination of a parasomnia and an eating disorder. It is described as being in a specific category within somnambulism or a state of sleepwalking that includes behaviors connected to a person's conscious wishes or wants. Thus many times NSRED is a person's fulfilling of their conscious wants that they suppress; however, this disorder is difficult to distinguish from other similar types of disorders.

NSRED is closely related to night eating syndrome (NES) except for the fact that those suffering from NES are completely awake and aware of their eating and bingeing at night while those suffering from NSRED are sleeping and unaware of what they are doing. NES is primarily considered an eating disorder while NSRED is primarily considered a parasomnia; however, both are a combination of parasomnia and eating disorders since those suffering from NES usually have insomnia or difficulty sleeping and those suffering from NSRED experience symptoms similar to binge eating. Some even argue over whether NES and NSRED are the same or distinct disorders. Even though there have been debates over these two disorders, specialists have examined them to try to determine the differences. Dr. J. Winkelman noted several features of the two disorders that were similar, but he gave one important factor that make these disorders different. In his article "Sleep-Related Eating Disorder and Night Eating Syndrome: Sleep Disorders, Eating Disorders, Or both", Winkelman said, "Both [disorders] involve nearly nightly binging at multiple nocturnal awakenings, defined as excess calorie intake or loss of control over consumption." He also reported that both disorders have a common occurrence of approximately one to five percent of adults, have been predominantly found in women, with a young adult onset, have a chronic course, have a primary morbidity of weight gain, sleep disruption, and shame over loss of control over food intake, have familial bases, and have been observed to have comorbid depression and daytime eating disorders. However, Winkelman said, "The most prominent cited distinction between NES and SRED is the level of consciousness during nighttime eating episodes." Therefore, these two disorders are extremely similar with only one distinction between them. Doctors and psychologists have difficulty differentiating between NES and NSRED, but the distinction of a person's level of consciousness is what doctors chiefly rely on to make a diagnosis. One mistake that is often made is the misdiagnosis of NSRED for NES. However, even though NSRED is not a commonly known and diagnosed disease, many people suffer from it in differing ways while doctors work to find a treatment that works for everyone; several studies have been done on NSRED, such as the one conducted by Schenck and Mahowald. These studies, in turn, provide the basic information on this disorder including the symptoms, behaviors, and possible treatments that doctors are using today.

A hypnic jerk, hypnagogic jerk, sleep start, sleep twitch or night start is an involuntary twitch which occurs when a person is beginning to fall asleep, often causing them to awaken suddenly for a moment. Physically, hypnic jerks resemble the "jump" experienced by a person when startled, sometimes accompanied by a falling sensation. Hypnic jerks are associated with a rapid heartbeat, quickened breathing, sweat, and sometimes "a peculiar sensory feeling of 'shock' or 'falling into the void. A higher occurrence is reported in people with irregular sleep schedules.

An individual displaying MERRFs syndrome will manifest not only a single symptom, but regularly patients display more than one affected body part at a time. It has been observed that patients with MERRF syndrome will primarily display Myoclonus as a first symptom, along with it they can also manifest seizures, cerebellar ataxia and myopathy. Secondary features include dementia, optic atrophy, bilateral deafness, peripheral neuropathy, spasticity or multiple lipomata. Additional symptoms include dementia, optic atrophy, bilateral deafness and peripheral neuropathy, spasticity, lipomatosis, and/or cardiomyopathy with wolff parkinson-white syndrome. Most patients will not exhibit all of these symptoms, however more than one of these symptoms will be present in a patient who has been diagnosed with MERRFS disease. Due to the multi-symptoms presented by the individual, the severity of the syndrome is very difficult to evaluate. Mitochondrial disorders may present at any age, and this holds truth for MERRS, since it forms part of them. Therefore, if a patient is presenting some of these symptoms, the doctor is able to narrow it down to MEERF mitochondrial disorder.

The cardinal features of Rolandic epilepsy are infrequent, often single, focal seizures consisting of:

Hemifacial sensorimotor seizures are often entirely localised in the lower lip or spread to the ipsilateral hand. Motor manifestations are sudden, continuous or bursts of clonic contractions, usually lasting from a few seconds to a minute. Ipsilateral tonic deviation of the mouth is also common. Hemifacial sensory symptoms consist of unilateral numbness mainly in the corner of the mouth.

Hemifacial seizures are often associated with an inability to speak and hypersalivation:

"The left side of my mouth felt numb and started jerking and pulling to the left, and I could not speak to say what was happening to me."

Negative myoclonus can be observed in some cases, as an interruption of tonic muscular activity

Oropharyngolaryngeal ictal manifestations are unilateral sensorimotor symptoms inside the mouth. Numbness, and more commonly paraesthesias (tingling, prickling, freezing), are usually diffuse on one side or, exceptionally, may be highly localised even to one tooth. Motor oropharyngolaryngeal symptoms produce strange sounds, such as death rattle, gargling, grunting and guttural sounds, and combinations:

"In his sleep, he was making guttural noises, with his mouth pulled to the right, ‘as if he was chewing his tongue’". "We heard her making strange noises ‘like roaring’ and found her unresponsive, head raised from the pillow, eyes wide open, rivers of saliva coming out of her mouth, rigid."

Arrest of speech is a form of anarthria. The child is unable to utter a single intelligible word and attempts to communicate with gestures.

"My mouth opened and I could not speak. I wanted to say I cannot speak. At the same time, it was as if somebody was strangling me."

Hypersalivation , a prominent autonomic manifestation, is often associated with hemifacial seizures, oro-pharyngo-laryngeal symptoms and speech arrest. Hypersalivation is not just frothing:

"Suddenly my mouth is full of saliva, it runs out like a river and I cannot speak."

Syncope-like epileptic seizures may occur, probably as a concurrent symptom of Panayiotopoulos syndrome:

"She lies there, unconscious with no movements, no convulsions, like a wax work, no life."

Consciousness and recollection are fully retained in more than half (58%) of Rolandic seizures.

"I felt that air was forced into my mouth, I could not speak and I could not close my mouth. I could understand well everything said to me. Other times I feel that there is food in my mouth and there is also a lot of salivation. I cannot speak."

In the remainder (42%), consciousness becomes impaired during the ictal progress and in one third there is no recollection of ictal events.

Progression to hemiconvulsions or generalised tonic–clonic seizures occurs in around half of children and hemiconvulsions may be followed by postictal Todd’s hemiparesis .

Duration and circadian distribution: Rolandic seizures are usually brief, lasting for 1–3 min. Three quarters of seizures occur during nonrapid eye movement sleep, mainly at sleep onset or just before awakening.

Status epilepticus: Although rare, focal motor status or hemiconvulsive status epilepticus is more likely to occur than secondarily generalised convulsive status epilepticus, which is exceptional. Opercular status epilepticus usually occurs in children with atypical evolution or may be induced by carbamazepine or lamotrigine. This state lasts for hours to months and consists of ongoing unilateral or bilateral contractions of the mouth, tongue or eyelids, positive or negative subtle perioral or other myoclonus, dysarthria, speech arrest, difficulties in swallowing, buccofacial apraxia and hypersalivation. These are often associated with continuous spikes and waves on an EEG during NREM sleep.

Other seizure types: Despite prominent hypersalivation, focal seizures with primarily autonomic manifestations (autonomic seizures) are not considered part of the core clinical syndrome of Rolandic epilepsy. However, some children may present with independent autonomic seizures or seizures with mixed Rolandic-autonomic manifestations including emesis as in Panayiotopoulos syndrome.

Atypical forms: Rolandic epilepsy may present with atypical manifestations such early age at onset, developmental delay or learning difficulties at inclusion, other seizure types, atypical EEG abnormalities.

These children usually have normal intelligence and development. Learning can remain unimpaired while a child is afflicted with Rolandic epilepsy.

Benign neonatal sleep myoclonus (BNSM) is the occurrence of myoclonus (jerky movements) during sleep. It is not associated with seizures.

Occurs in the first few weeks of life, usually resolves in first 2–3 months of life. Often worries parents because they appear like seizures, but they are not. Features that can help distinguish this condition from seizures include: The myoclonic movements only occur during sleep, when baby is woken up the myoclonic movements stop, normal EEG, normal neurological examination, normal developmental examination. The myoclonic jerks occur during non-REM sleep

Benign Rolandic epilepsy or benign childhood epilepsy with centrotemporal spikes (BCECTS) is the most common epilepsy syndrome in childhood. Most children will outgrow the syndrome (it starts around the age of 3-13 with a peak around 8–9 years and stops around age 14-18), hence the label benign. The seizures, sometimes referred to as "sylvian seizures", start around the central sulcus of the brain (also called the centrotemporal area, located around the Rolandic fissure, after Luigi Rolando).

RHS type 1 is caused by the impairment of a regulatory mechanism between cerebellar and brainstem nuclei and has been associated with a wide range of diseases, including Lafora disease, dentatorubropallidoluysian atrophy, and celiac disease.

Thorough history regarding frequency of bedwetting, any period of dryness in between, associated daytime symptoms, constipation, and encopresis should be sought.

Nocturnal awakenings are more common in older patients and have been associated with depressive disorders, chronic pain, obstructive sleep apnea, obesity, alcohol consumption, hypertension, gastroesophageal reflux disease, heart disease, menopause, prostate problems, and bipolar disorders.

Nocturnal awakenings can be mistaken as shift work disorder.

Benign occipital epilepsy of childhood (BOEC) is an idiopathic localization-related epilepsy and consists of an evolving group of syndromes. Most authorities include two subtypes, an early subtype with onset between three and five years, and a late onset between seven and 10 years. Seizures in BOEC usually feature visual symptoms such as scotoma or fortifications (brightly colored spots or lines) or amaurosis (blindness or impairment of vision). Convulsions involving one half the body, hemiconvulsions, or forced eye deviation or head turning are common. Younger patients typically experience symptoms similar to migraine with nausea and headache, and older patients typically complain of more visual symptoms. The EEG in BOEC shows spikes recorded from the occipital (back of head) regions. The EEG and genetic pattern suggest an autosomal dominant transmission as described by Ruben Kuzniecky, et al. Lately, a group of epilepsies termed Panayiotopoulos syndrome that share some clinical features of BOEC but have a wider variety of EEG findings are classified by some as BOEC.

The medical name for bedwetting is "nocturnal enuresis". The condition is divided into 2 types: primary nocturnal enuresis (PNE) and secondary nocturnal enuresis.