Use of olfactory training in post-traumatic and postinfectious olfactory dysfunction

Laryngoscope. 2013 Dec;123(12):E85-90. doi: 10.1002/lary.24390. Epub 2013 Oct 4.


Objectives/hypothesis: There is evidence that the olfactory system can be modulated by repeated exposure to odors, a procedure called olfactory training. The aim of this study was to assess the effectiveness of olfactory training in patients with postinfectious and post-traumatic olfactory dysfunction.

Study design: Prospective study of 119 patients with postinfectious and post-traumatic olfactory dysfunction.

Methods: Two groups of patients (postinfectious and post-traumatic) performed the olfactory training (n = 49 and n = 23, respectively) over a period of 16 weeks and were compared with two control groups of the same etiology (n = 32 and n = 15). Patients with sinunasal, neurologic, or idiopathic disease were excluded. Training was performed twice daily with the use of four odors (phenyl ethyl alcohol [rose], eucalyptol [eucalyptus], citronellal [lemon], and eugenol [cloves]). Olfactory testing was performed by means of the Sniffin' Sticks test battery (threshold, discrimination, identification) at the time of diagnosis, and 8 and 16 weeks later. All patients evaluated their olfactory function by means of a visual analogue scale (0-100).

Results: Compared to controls, training patients in both groups presented significantly higher scores of olfactory function as measured by the Sniffin' Sticks test. This increase was measured in 67.8% of postinfectious and 33.2% of post-traumatic patients. Subjective ratings were in accordance with the olfactory test results. Subset analysis showed that olfactory function mainly increased olfactory identification followed by discrimination in both training groups.

Conclusions: The present study suggests that a 16-week short-term exposure to specific odors may increase olfactory sensitivity in patients with postinfectious and post-traumatic olfactory dysfunction.

Keywords: Anosmia; olfactory training; post-traumatic; postinfectious.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Craniocerebral Trauma / complications*
  • Craniocerebral Trauma / diagnosis
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Odorants
  • Olfaction Disorders / etiology
  • Olfaction Disorders / physiopathology
  • Olfaction Disorders / rehabilitation*
  • Prospective Studies
  • Psychotherapeutic Processes*
  • Recovery of Function*
  • Respiratory Tract Infections / complications*
  • Respiratory Tract Infections / diagnosis
  • Sensory Thresholds
  • Smell / physiology*
  • Treatment Outcome