title: Reorganization of sleep patterns in severe OSAS under prolonged CPAP treatment.
abstract: OBJECTIVE
  To evaluate the immediate and long-term recovery processes of sleep and daytime vigilance in patients with sleep apnea syndrome (OSAS) after continuous CPAP treatment.
  
  
  METHODS
  Five consecutive polysomnographic (PSG) studies were carried out on 10 male patients with severe OSAS. The first recording (baseline) was accomplished without ventilatory support (N0). The other 4 recordings were carried out during the CPAP titration night (N1), during the second night of treatment (N2), during the third night of treatment (N3), and after 30 days of regular CPAP use (N30). Ten age-balanced healthy male subjects were selected from the Parma Sleep Center database as controls. Respiratory variables, conventional PSG variables, arousals, CAP (cyclic alternating pattern) variables, and daytime function (including MSLT) were quantified. ANOVA followed by post-hoc tests explored the differences between controls and OSAS patients in the different recording conditions (N0, N1, N2, N3, N30). The PSG measures that showed significant ANOVA values were correlated with the MSLT scores.
  
  
  RESULTS
  Values of control subjects were recovered by REM sleep, REM latency, subtypes A3 and arousal index during N1, by CAP rate and total arousals during N2, by deep sleep (stages 3 + 4) during N3, by light sleep (stages 1 + 2) during N30. The only measures which remained below control values even after 1 month of sustained treatment were the amount of CAP cycles and A1 subtypes. MSLT scores correlated significantly with CAP rate, deep sleep and arousals.
  
  
  CONCLUSIONS
  The changes induced by CPAP treatment do not restore immediately a normal sleep structure, which is re-established with different time scales
  
  
  CONCLUSIONS
  The modifications of sleep patterns and the different adjustments of phase A subtypes allow us to monitor the reorganization of sleep in OSAS patients treated with CPAP and the hierarchy of the mechanisms involved in sleep regulation.
authors.affiliation: Sleep Disorders Center, Department of Neuroscience, Azienda Ospedaliera Universitaria, University of Parma, Via Gramsci 14, Parma 43100, Italy.
authors.forename: Liborio
authors.initials: L
authors.lastname: Parrino
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Thomas
authors.forename: Arianna
authors.initials: A
authors.lastname: Smerieri
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Spaggiari
authors.forename: Alessandra
authors.initials: A
authors.lastname: Del Felice
authors.forename: Mario Giovanni
authors.initials: MG
authors.lastname: Terzano
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D045422:Continuous Positive Airway Pressure; D004569:Electroencephalography; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015656:Respiratory Mechanics / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*; D012895:Sleep, REM / Q000502:physiology