title: [The role of slow wave sleep in the homeostatic regulation of sleep].
abstract: OBJECTIVE
  The homeostatic regulation of sleep is based on the model devised by Borb ly in 1982. During the sleep waking cycle there is an interaction between the natural tendency to sleep, which increase as the vigil is prolonged (S process) and the circadian variation (C process). In this study, we aimed to find how slow activity (0.5 4.5 Hz) during sleep (SWA), mainly registered in phases 3 and 4, may be an indicator of process S.
  
  
  METHODS
  We compared two groups of persons: 10 with chronic sleep deprivation (CSD) (less than 6 hours of sleep/day) as compared with 10 persons who slept more than 6 hours per day, using spectral analysis of their delta activity during sleep.
  
  
  RESULTS
  There was a predominance of delta activity in the group of persons with CSD as compared with the control group.
  
  
  CONCLUSIONS
  An increase in SWA was accompanied by an increased tendency to sleep and may therefore be considered to be a marker for this. This marker allows conditions associated with hypersomnolence due to alteration of process S to be identified.
authors.affiliation: Servicio de Neurofisiolog a Cl nica; Hospital Cl nico Universitario San Carlos, Madrid, 28040, Espańa. AIPUENTE@teleline.es
authors.forename: A I
authors.initials: AI
authors.lastname: Puente-Muńoz
authors.forename: D A
authors.initials: DA
authors.lastname: Pérez-Martínez
authors.forename: I
authors.initials: I
authors.lastname: Villalibre-Valderrey
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003700:Delta Rhythm; D006970:Disorders of Excessive Somnolence / Q000209:etiology; D004569:Electroencephalography; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000150:complications / Q000175:diagnosis; D012895:Sleep, REM / Q000502:physiology