title: [Arousal and its influence on vigilance].
abstract: BACKGROUND
  The term arousal usually refers to transient, brief arousal during nocturnal sleep or to a state of vigilance which is maintained during the day.
  
  
  CONCLUSIONS
  In this review we consider the various accepted meanings and clinical disorders of 'arousal'. Insomnia (hyperarousal), parasomnias (partial arousal) and the sudden death syndrome of infancy are all attributed to disorders of arousal. It is concluded that diurnal hyperarousal leads to difficulty in getting off to sleep and staying asleep, whilst nocturnal arousal leads to excessive somnolence during the day, due to broken sleep during the night.
authors.affiliation: Unidad de Sueño, Hospital Clínico San Carlos, Madrid, España.
authors.forename: J
authors.initials: J
authors.lastname: Espinar-Sierra
mesh_terms: D001143:Arousal / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D020921:Sleep Arousal Disorders / Q000175:diagnosis*; D012895:Sleep, REM / Q000502:physiology; D014851:Wakefulness / Q000502:physiology*