Sleep terror

Night terror, also known as sleep terror, is a sleep disorder causing feelings of terror or dread typically occurring during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep and lasting for 1 to 10 minutes. They can last longer, especially in children. Sleep terrors are then classified in the category of NREM-related parasomnias in the International Classification of Sleep Disorders. There are two other categories: REM-related parasomnias and other parasomnias. Parasomnias are qualified as undesirable physical events or experience that occur during entry into sleep, within sleep, or during arousals from sleep. Night terror, also known as sleep terror, is a sleep disorder causing feelings of terror or dread typically occurring during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep and lasting for 1 to 10 minutes. They can last longer, especially in children. Sleep terrors are then classified in the category of NREM-related parasomnias in the International Classification of Sleep Disorders. There are two other categories: REM-related parasomnias and other parasomnias. Parasomnias are qualified as undesirable physical events or experience that occur during entry into sleep, within sleep, or during arousals from sleep. Sleep terrors usually begin in childhood and usually decrease with age. Factors which may lead to sleep terrors are young age, sleep deprivation, medications, stress, fever and intrinsic sleep disorders. Though the frequency and severity vary between individuals, the episodes can occur in intervals of days or weeks, but can also occur over consecutive nights or multiple times in one night. This has created a situation in which any type of nocturnal attack or nightmare may be confused with and reported as a night terror. Night terrors tend to happen during periods of arousal from delta sleep, also known as slow-wave sleep. Delta sleep occurs most often during the first half of a sleep cycle, which indicates that people with more delta sleep activity are more prone to night terrors. However, they can also occur during daytime naps. Night terrors can often be mistaken for confusional arousal. While nightmares (bad dreams that cause feelings of horror or fear) are relatively common during childhood, night terrors occur less frequently. The prevalence of sleep terrors in general is unknown. Sleep terror episodes (not similar to sleep terror disorder which is recurrent and causes distress or impairment ) are estimated at 36.9% at 18 months of age and at 19.7% at 30 months of age. In adults the prevalence is lower, and rises up to 2.2%. Night terrors have been known since ancient times, although it was impossible to differentiate them from nightmares until rapid eye movement was discovered. The universal feature of night terrors is inconsolability, very similar to that of a panic attack. During night terror bouts, people are usually described as 'bolting upright' with their eyes wide open and a look of fear and panic on their faces. They will often scream. Furthermore, they will usually sweat, exhibit rapid breathing, and have a rapid heart rate (autonomic signs). In some cases, individuals are likely to have even more elaborate motor activity, such as a thrashing of limbs—which may include punching, swinging, or fleeing motions. There is a sense that the individuals are trying to protect themselves and/or escape from a possible threat of bodily injury. Although people may seem to be awake during a night terror, they will appear confused, be inconsolable and/or unresponsive to attempts to communicate with them, and may not recognize others familiar to them. Occasionally, when a person with a night terror is awakened, they will lash out at the one awakening them, which can be dangerous to that individual. Most people who experience this do not remember the incident the next day, although brief dream images or hallucinations may occur and be recalled. Sleepwalking is also common during night terror bouts, as sleepwalking and night terrors are different manifestations of the same parasomnia. During lab tests, subjects are known to have very high voltages of electroencephalography (EEG) delta activity, an increase in muscle tone, and a doubled increase in heart rate, if not more. Brain activities during a typical episode show theta and alpha activity when using an EEG. It is also common to see abrupt arousal from NREM sleep that does not progress into a full episode of a night terror. These episodes can include tachycardia. Night terrors are also associated with intense autonomic discharge of tachypnea, flushing, diaphoresis, and mydriasis—that is, unconscious or involuntary rapid breathing, reddening of the skin, profuse sweating, and dilation of the pupils. In children with night terrors, there is no increased occurrence of psychiatric diagnoses. However, in adults who suffer from night terrors there is a close association with psychopathology or mental disorders. There may be an increased occurrence of night terrors—particularly among those suffering or having suffered from post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD). It is also likely that some personality disorders may occur in individuals with night terrors, such as dependent, schizoid, and borderline personality disorders. There have been some symptoms of depression and anxiety that have increased in individuals that have suffered from frequent night terrors. Low blood sugar is associated with both pediatric and adult night terrors. A study of adults with thalamic lesions of the brain and brainstem have been occasionally associated with night terrors. Night terrors are closely linked to sleepwalking and frontal lobe epilepsy. Night terrors typically occur in children between the ages of three and twelve years, with a peak onset in children aged three and a half years old.An estimated 1–6% of children experience night terrors. Children of both genders and all ethnic backgrounds are affected equally. In children younger than three and a half years old, peak frequency of night terrors is at least one episode per week. Among older children, peak frequency of night terrors is one or two episodes per month. The children will most likely have no recollection of the episode the next day. Pediatric evaluation may be sought to exclude the possibility that the night terrors are caused by seizure disorders or breathing problems. Most children will outgrow sleep terrors. Night terrors in adults have been reported in all age ranges. Though the symptoms of night terrors in adolescents and adults are similar, the cause, prognosis and treatment are qualitatively different. These night terrors can occur each night if the sufferer does not eat a proper diet, get the appropriate amount or quality of sleep (e.g. sleep apnea), is enduring stressful events, or if he or she remains untreated. Adult night terrors are much less common, and often respond to treatments to rectify causes of poor quality or quantity of sleep. Night terrors are classified as a mental and behavioral disorder in the ICD. A study done about night terrors in adults showed that other psychiatric symptoms were prevalent in most patients experiencing night terrors hinting at the comorbidity of the two. There is some evidence of a link between night terrors and hypoglycemia.