title: Arousal responses to olfactory or trigeminal stimulation during sleep.
abstract: OBJECTIVE
  The interaction of sensory physiology and sleep has been studied for various sensory systems. Nevertheless, the question whether chemosensory (especially olfactory) stimuli may lead to arousals during sleep remains under discussion. Specifically, the central processing of olfactory information shows fundamental differences compared to other sensory systems.
  
  
  METHODS
  Prospective controlled trial.
  
  
  METHODS
  Sleep research facility, University Hospital.
  
  
  METHODS
  Five young healthy, normosmic volunteers.
  
  
  METHODS
  Intranasal chemosensory stimulation during sleep was based on air-dilution olfactometry. For olfactory stimulation H2S (smell of rotten eggs) was used in 4 concentrations (1, 2, 4, and 8 ppm). For trigeminal stimulation CO2 (stinging sensation) was also administered in 4 concentrations (10%, 20%, 40%, and 60% v/v) while odorless stimuli were used for control.
  
  
  METHODS
  Arousal reactions due to chemosensory stimulation were assessed during overnight polysomnography 30 seconds after the presentation of every stimulus during 23 nights of testing.
  
  
  RESULTS
  For olfactory testing, an average number of 703 olfactory stimuli and 157 odorless controls were used for analysis per subject. Even the highest stimulus concentration did not produce an increase in arousal frequency. For trigeminal testing, an average number of 405 stimuli and 79 controls were used for analysis per subject, and an increase in arousal frequency was observed following the increase of stimulus concentration.
  
  
  CONCLUSIONS
  With the present results we were able to demonstrate that, in contrast to trigeminal stimulation, the presentation of a strong but selective olfactory stimulus does not lead to arousals during nocturnal sleep in humans.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Germany. boris.stuck@hno.ma.uni-heidelberg.de
authors.forename: Boris A
authors.initials: BA
authors.lastname: Stuck
authors.forename: Kathrin
authors.initials: K
authors.lastname: Stieber
authors.forename: Sabine
authors.initials: S
authors.lastname: Frey
authors.forename: Christopher
authors.initials: C
authors.lastname: Freiburg
authors.forename: Karl
authors.initials: K
authors.lastname: Hörmann
authors.forename: Joachim T
authors.initials: JT
authors.lastname: Maurer
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology; D002628:Chemoreceptor Cells / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008032:Limbic System / Q000502:physiology; D009297:Nasal Mucosa / Q000294:innervation; D009832:Olfactory Nerve / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D017286:Polysomnography; D012684:Sensory Thresholds / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D012903:Smell / Q000502:physiology*; D014276:Trigeminal Nerve / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide