<unk>  lacks a clearly defining biological marker like HLA-DQB1*0602 genotype in narcolepsy. Doctors can more carefully exclude these causes of EDS in order to more correctly diagnose IH. However, "even in the presence of other specific causes of<unk> , one should carefully assess the contribution of these etiological factors to the complaint of EDS and when specific treatments of these conditions fail to suppress EDS, the additional diagnosis of IH should be considered." The severity of EDS can be quantified by subjective scales, such as the Epworth Sleepiness Scale and the Stanford Sleepiness Scale, and also by objective tests, like actigraphy, psychomotor vigilance task, maintenance of wakefulness test (MWT), multiple sleep latency test (MSLT) although as per latest research studies, the effectiveness of MSLT has been called into question. Several groups of researchers have found normal MSLT results in patients who otherwise seem to have IH. Therefore, when IH is suspected, researchers suggest appending a 24-hour continuous polysomnography to the standard overnight/MSLT study in order to record total sleep time. The recent studies have also found that reports of sleepiness in IH relate more to mental fatigue rather than physiological sleepiness per se and the subjective scales like ESS, IH symptom diary (IHSD) and PGIC better captures the severity of symptoms consistently. It is also important to note that whereas narcolepsy is strongly associated with the HLA-DQB1*0602 genotype, "HLA typing is of no help in the positive diagnosis of<unk> ." This is "despite some reports that suggest an increase sic frequency of HLA Cw2 and DRS in<unk>  subjects." In patients with IH, polysomnography typically shows short sleep latency, increased mean slow wave sleep, and a high mean sleep efficiency. "Latency to REM sleep and percentages of light sleep and REM sleep were normal, compared with normal ranges." Despite this, one study has found increased sleep fragmentation in patients with IH without long sleep time, suggesting multiple possible presentations. Per ICSD-3, five criteria must be met for a diagnosis of IH: # Daytime lapses into sleep or an irrepressible need to sleep on a daily basis, for at least 3 months # Absence of insufficient sleep syndrome # Absence of cataplexy # Absence of other causes of<unk>  # The presence of positive MSLT tests. The latest ICD 10 defines IH with long sleep time as a neurological disorder that is a rare sleep disorder characterized by prolonged sleep at night and extreme sleepiness during the day. There are no apparent causes. This disorder affects the ability to function. It is of central nervous system origin characterized by prolonged nocturnal sleep and periods of daytime drowsiness. Affected individuals experience difficulty with awakening in the morning and may have associated sleep drunkenness, automatic behaviors, and memory disturbances. This condition differs from narcolepsy in that daytime sleep periods are longer, there is no association with cataplexy, and the multiple sleep latency onset test does not record sleep-onset rapid eye movement sleep.
Idiopathic hypersomnia
Strephosymbolia
Psychoorganic syndrome
Nightmare disorder
Erotolepsy
Interictal dysphoric disorder
Narcolepsy
Klazomania