medical importance of sleep was recognized. by the 1970s in the us, clinics and laboratories devoted to the study of sleep and sleep disorders had been founded, and a need for standards arose. the medical community began paying more attention to primary sleep disorders, such as sleep apnea, as well as the role and quality of sleep in other conditions. specialists in sleep medicine were originally and continue to be certified by the american board of sleep medicine. those passing the sleep medicine specialty exam received the designation "diplomate of the absm." sleep medicine is now a recognized subspecialty within internal medicine, family medicine, pediatrics, otolaryngology, psychiatry and neurology in the united states. certification in sleep medicine shows that the specialist:"has demonstrated expertise in the diagnosis and management of clinical conditions that occur during sleep, that disturb sleep, or that are affected by disturbances in the wake-sleep cycle. this specialist is skilled in the analysis and interpretation of comprehensive polysomnography, and well-versed in emerging research and management of a sleep laboratory." competence in sleep medicine requires an understanding of a myriad of very diverse disorders. many of which present with similar symptoms such as excessive daytime sleepiness, which, in the absence of volitional sleep deprivation, "is almost inevitably caused by an identifiable and treatable sleep disorder", such as sleep apnea, narcolepsy, idiopathic hypersomnia, kleine–levin syndrome, menstrual-related hypersomnia, idiopathic recurrent stupor, or circadian rhythm disturbances. another common complaint is insomnia, a set of symptoms which can have a great many different causes, physical and mental. management in the varying situations differs greatly and cannot be undertaken without a correct diagnosis. sleep dentistry (bruxism, snoring and sleep apnea), while not recognized as one of the nine dental specialties, qualifies for board-certification by the american board of dental sleep medicine (abdsm). the qualified dentists collaborate with sleep physicians at accredited sleep centers, and can provide oral appliance therapy and upper airway surgery to treat or manage sleep-related breathing disorders. the resulting diplomate status is recognized by the american academy of sleep medicine (aasm), and these dentists are organized in the academy of dental sleep medicine (usa). occupational therapy is an area of medicine that can also address a diagnosis of sleep disorder, as rest and sleep is listed in the occupational therapy practice framework (otpf) as its own occupation of daily living. rest and sleep are described as restorative in order to support engagement in other occupational therapy occupations. in the otpf, the occupation of rest and sleep is broken down into rest, sleep preparation, and sleep participation. occupational therapists have been shown to help improve restorative sleep through the use of assistive devices/equipment, cognitive behavioral therapy for insomnia, therapeutic activities, and/or lifestyle interventions. in the uk, knowledge of sleep medicine and possibilities for diagnosis and treatment seem to lag. the imperial college healthcare shows attention to obstructive sleep apnea syndrome (osa) and very few other sleep disorders. some nhs trusts have specialist clinics for respiratory and/or neurological sleep medicine. epidemiology children and young adults according to one meta-analysis of sleep disorders in children, confusional arousals and sleepwalking are the two most common sleep disorders among children. an estimated 17.3% of kids between 3 and 13 years old experience confusional arousals. about 17% of children sleepwalk, with the disorder being more common among boys than girls, the peak ages of sleepwalking are from 8 to 12 years old. a different systematic review offers a high range of prevalence rates of sleep bruxism for children. parasomnias like sleepwalking and talking typically occur during the first part of an individual's sleep cycle, the first slow wave of sleep during the first slow wave of sleep period of the sleep cycle the mind and body slow down causing one to feel drowsy and relaxed. at this stage it is the easiest to wake up, therefore many children do not remember what happened during this time. nightmares are also considered a parasomnia among children, who typically remember what took place during the nightmare. however, nightmares only occur during the last stage of sleep - rapid eye movement (rem) sleep. rem is the deepest stage of sleep, it is named for the host of neurological and physiological responses an individual can display during this period of the sleep cycle which are similar to being awake. between 15.29% and 38.6% of preschoolers grind their teeth at least one night a week. all but one of the included studies reports decreasing bruxist prevalence as age increased, as well as a higher prevalence among boys than girls. another systematic review noted 7-16% of young adults have delayed sleep phase disorder. this disorder reaches peak prevalence when people are in their 20s. between 20 and 26% of adolescents report a sleep onset latency of greater than 30 minutes. also, 7-36% have difficulty initiating sleep. asian teens tend to have a higher prevalence of all of these adverse sleep outcomes—than their north american and european counterparts. by adulthood, parasomnias can normally be resolved due to a person's growth; however, 4% of people have recurring symptoms. effects of untreated sleep disorders children and young adults who do not get enough sleep due to sleep disorders also have many other health problems such as obesity and physical problems where it could interfere with everyday life. it is recommended that children and young adults stick to the hours of sleep recommended by the cdc, as it helps increase mental health, physical health, and more. insomnia insomnia is a prevalent form of sleep deprivation. individuals with insomnia may have problems falling asleep, staying asleep, or a combination of both resulting in hyposomnia - i.e. insufficient quantity and poor quality of sleep. combining results from 17 studies on insomnia in china, a pooled prevalence of 15.0% is reported for the country. this result is consistent among other east asian countries; however, this is considerably lower than a series of western countries (50.5% in poland, 37.2% in france and italy, 27.1% in usa). men and women residing in china experience insomnia at similar rates. a separate meta-analysis focusing on this sleeping disorder in the elderly mentions that those with more than one physical or psychiatric malady experience it at a 60% higher rate than those with one condition or less. it also notes a higher prevalence of insomnia in women over the age of 50 than their male counterparts. a study that was resulted from a collaboration between massachusetts general hospital and merck describes the development of an algorithm to identify patients with sleep disorders using electronic medical records. the algorithm that incorporated a combination of structured and unstructured variables identified more than 36,000 individuals with physician-documented insomnia. insomnia can start off at the basic level but about 40% of people who struggle with insomnia have worse symptoms. there are treatments that can help with insomnia and that includes medication, planning out a sleep schedule, limiting oneself from caffeine intake, and cognitive behavioral therapy. obstructive sleep apnea obstructive sleep apnea (osa) affects around 4% of men and 2% of women in the united states. in general, this disorder is more prevalent among men. however, this difference tends to diminish with age. women experience the highest risk for osa during pregnancy, and tend to report experiencing depression and insomnia in conjunction with obstructive sleep apnea. in a meta-analysis of the various asian countries, india and china present the highest prevalence of the disorder. specifically, about 13.7% of the indian population and 7% of hong kong's population is estimated to have osa. the two groups in the study experience daytime osa symptoms such as difficulties concentrating, mood swings, or high blood pressure, at similar rates (prevalence of 3.5% and 3.57%, respectively). sleep paralysis a systematic review states 7.6% of the general population experiences sleep paralysis at least once in their lifetime. its prevalence among men is 15.9%, while 18.9% of women experience it. when considering specific populations, 28.3% of students and 31.9% of psychiatric patients have experienced this phenomenon at least once in their lifetime. of those psychiatric patients, 34.6% have panic disorder. sleep paralysis in students is slightly more prevalent for those of asian descent (39.9%) than other ethnicities (hispanic: 34.5%, african descent: 31.4%, caucasian 30.8%). restless leg syndrome according to one meta-analysis, the average prevalence rate for north america and western europe is estimated to be 14.5±8.0%. specifically in the united states, the prevalence of restless leg syndrome is estimated to be between 5% and 15.7% when using strict diagnostic criteria. rls is over 35% more prevalent in american women than their male counterparts.