Parasomnias

Excerpt

Literary allusions referencing the phenomenology of sleep are evident throughout history, as evident in Virgil's (70 B.C. - 19 B. C.) Aeneid, 'That sweet, deep sleep, so close to tranquil death'. This perennial fascination with sleep has even engendered appraisal in mythology. In ancient Greece, sleep was personified by the deity Hypnos, while his Roman equivalent was named Somnos. Even now, the precise impetus of the phenomenology of sleep remains elusive, leading to a somewhat residual arcane enchantment with sleep.

Sleep disturbances are one of the most abundant presentations in the outpatient setting. In fact, up to 50% of chief complaints in the primary care setting correlate with maladaptive sleep patterns. Normal sleep architecture is composed of rapid eye movement (REM) and non-REM (NREM). NREM is further subdivided into four stages, stage 0, stage 1, stage 2, and stage 3. NREM and REM alternate in a cycle that lasts about 120 minutes. The initial REM stage lasts about 5-10 minutes, followed by progressively protracted and frequent periods.

Disruptions to this sleep cycle, either during continuous sleep or upon the transition to wakefulness, are categorized under the nosology of 'parasomnias'. The nomenclature of 'parasomnias' was first introduced by Henri Roger in 1932. The etymology derives from the prefix para (Greek) - 'alongside' - and the noun Somnus (Latin) - 'sleep'. Parasomnias are characterized by aberrant behavioral, phenomenological, or physiological events in accordance with sleep. The most prevalent deviant patterns of sleep arousal, and the ones of salience for this scholastic endeavor, consist of 'REM sleep behavior disorder,' 'NREM sleep arousal disorders,' and 'nightmare disorder'.