title: Differences in clinical features of upper airway resistance syndrome, primary snoring, and obstructive sleep apnea/hypopnea syndrome.
abstract: BACKGROUND
  The clinical features of patients with upper airway resistance syndrome (UARS) have previously been compared to patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). No data regarding differences between patients with primary snoring (PS) or patients with obstructive sleep apnea/hypopnea without daytime sleepiness (OSAH) are available. We conducted a study to investigate clinical features of UARS, comparing them to those in patients with PS, OSAH, and OSAHS.
  
  
  METHODS
  Retrospective chart analysis of 157 patients with PS, 424 patients with UARS, 562 patients with OSAH, and 1610 patients with OSAHS seen in two sleep disorders clinics between 1996 and 2006. All patients had a diagnostic polysomnography (PSG) and a comprehensive clinical history taken by board-certified sleep specialists.
  
  
  RESULTS
  PS and UARS patients were significantly younger, less overweight and had lower weight gain during the past 5years. The female-to-male ratio was highest in the UARS group. UARS patients had significantly less stage non-rapid eye movement sleep (NREM) 1 and NREM 2 and significantly more NREM 3 and NREM 4 sleep than OSAH and OSAHS patients. Arousal indices between PS/UARS and OSAH/OSAHS patients were significantly lower, with no significant difference within these diagnostic categories. Patients with UARS presented the highest degree of subjective impairment.
  
  
  CONCLUSIONS
  UARS patients share some clinical features of patients with OSAHS and PS, although these two groups differ in their presentation of clinical sleepiness. Patients with UARS were most impaired in terms of their daily functioning and perception of sleep quality. This finding could not be corroborated by objective measures.
authors.affiliation: Somnolab - Dortmund Sleep Disorders Center, Hörder Burgstr. 18, 44263 Dortmund, Germany. rastoohs@somnolab.de
authors.forename: Riccardo A
authors.initials: RA
authors.lastname: Stoohs
authors.forename: Lennart
authors.initials: L
authors.lastname: Knaack
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Blum
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Janicki
authors.forename: Winfried
authors.initials: W
authors.lastname: Hohenhorst
mesh_terms: D001143:Arousal / Q000502:physiology; D015992:Body Mass Index; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D003937:Diagnosis, Differential; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology; D012894:Sleep Stages; D012913:Snoring / Q000175:diagnosis* / Q000503:physiopathology*