title: Lateralized differences in olfactory function.
abstract: BACKGROUND
  Birhinal testing of odor identification will not allow the detection of unilateral olfactory loss. The aim of the presented study was to evaluate side differences of odor identification in large groups of healthy subjects and in patients with nasal symptoms.
  
  
  METHODS
  Self-assessment of olfactory function and evaluation of olfactory function by means of a validated test were performed in 479 healthy subjects, in 765 patients with chronic rhinosinusitis (CRS), and in 53 patients with a tumor. A 12-item odor identification test ("Sniffin' Sticks") was used to evaluate olfactory function separately for each nostril.
  
  
  RESULTS
  Fifteen percent of the healthy subjects demonstrated side differences in the identification of at least 3 out of 12 odors. Healthy elderly subjects showed larger side differences in identification of odor than younger ones; a general difference between odor identification with the right or left nostril was not found. Both CRS patients and patients with a tumor had larger side differences than healthy subjects. Only 20% of the patients with a tumor complained about impaired olfactory sensitivity, but more than 75% of them showed deficits in olfactory tests.
  
  
  CONCLUSIONS
  Side differences of odor identification of 25% or greater should give reason for further investigation. Future studies are needed to investigate whether side differences in healthy subjects are a predicator of a higher risk for general olfactory loss.
authors.affiliation: Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Gudziol
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hummel
authors.forename: Simona
authors.initials: S
authors.lastname: Negoias
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishimaru
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009669:Nose Neoplasms / Q000503:physiopathology; D000857:Olfaction Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D010255:Paranasal Sinus Neoplasms / Q000503:physiopathology; D012220:Rhinitis / Q000503:physiopathology; D012647:Self-Assessment; D012852:Sinusitis / Q000503:physiopathology; D012903:Smell / Q000502:physiology*