Mechanical obstruction of the olfactory cleft reveals differences between orthonasal and retronasal olfactory functions.

Following up on recent observations in patients with nasal polyposis (NP), the present study aimed to investigate whether a mechanical obstruction of the anterior olfactory cleft (OC) would produce differential effects on orthonasal and retronasal olfactory functions. To this end, we studied 33 healthy subjects in a randomized trial. Sponges with high content of saline were either placed in the OC or on the respiratory epithelium, such that this was blinded to both subject and observer. The results indicated that orthonasal (P = 0.04) but not retronasal (P = 0.15) olfactory identification ability was lower when the OC was blocked. This confirms the idea that differences between orthonasal and retronasal olfactory functions, as observed in NP patients, are, at least to some degree, due to mechanical obstruction of the anterior portion of the OC. The present data also suggest that mechanical obstruction is a means to induce reversible hyposmia void of side effects which can be performed in a blinded fashion. This might become a valuable model of hyposmia for future investigations.

[1]  T. Hummel,et al.  Differences between orthonasal and retronasal olfactory functions in patients with loss of the sense of smell. , 2005, Archives of otolaryngology--head & neck surgery.

[2]  D. Small,et al.  Differential Neural Responses Evoked by Orthonasal versus Retronasal Odorant Perception in Humans , 2005, Neuron.

[3]  R. Doty,et al.  Effects of drugs on olfaction and taste. , 2004, Otolaryngologic clinics of North America.

[4]  G. Kobal,et al.  Anesthesia affects olfaction and chemosensory event-related potentials , 2004, Clinical Neurophysiology.

[5]  T. Hummel,et al.  Retronasal olfactory function in nasal polyposis , 2003, The Laryngoscope.

[6]  Jan Born,et al.  Sniffing neuropeptides: a transnasal approach to the human brain , 2002, Nature Neuroscience.

[7]  Thomas Hummel,et al.  Clinical assessment of retronasal olfactory function. , 2002, Archives of otolaryngology--head & neck surgery.

[8]  T. Hummel,et al.  Decreased Trigeminal Sensitivity in Anosmia , 2001, ORL.

[9]  S. Okuyama.  The first attempt at radioisotopic evaluation of the integrity of the nose-brain barrier. , 1997, Life sciences.

[10]  J. Lötsch,et al.  Loss of olfactory function leads to a decrease of trigeminal sensitivity. , 1996, Chemical senses.

[11]  D. Perl,et al.  Aluminum, Alzheimer's Disease, and the Olfactory System a , 1991, Annals of the New York Academy of Sciences.

[12]  G Kobal,et al.  Cerebral chemosensory evoked potentials elicited by chemical stimulation of the human olfactory and respiratory nasal mucosa. , 1988, Electroencephalography and clinical neurophysiology.

[13]  William S. Cain,et al.  Interaction between chemoreceptive modalities of odour and irritation , 1980, Nature.

[14]  W. Cain.  CONTRIBUTION OF THE TRIGEMINAL NERVE TO PERCEIVED ODOR MAGNITUDE * , 1974 .

[15]  L. Klimek,et al.  Multicenter investigation of 1,036 subjects using a standardized method for the assessment of olfactory function combining tests of odor identification, odor discrimination, and olfactory thresholds , 2000, European Archives of Oto-Rhino-Laryngology.