title: Long-term follow-up of olfactory loss secondary to head trauma and upper respiratory tract infection.
abstract: OBJECTIVE
  To determine the extent to which olfactory function can improve after loss induced by head trauma or a previous upper respiratory tract infection (URI) and the time for this improvement for more effective patient counseling.
  
  
  METHODS
  Patients initially evaluated at the University of Cincinnati (Ohio) Taste and Smell Center were reevaluated for olfactory loss with the University of Pennsylvania (Philadelphia) Smell Identification Test 1 to 5 years after initial testing. Changes in score on this test were used to indicate improvement in sensory function. Subjective information on olfactory ability and olfactory symptoms was also collected.
  
  
  METHODS
  University-based tertiary care center.
  
  
  METHODS
  Forty-one patients with olfactory loss induced by head trauma (20) or previous URI (21).
  
  
  RESULTS
  Seven (35%) of 20 patients with head trauma improved on the smell test by 4 points or more. Fourteen of 21 (67%) patients with a previous URI had improved scores of this magnitude or more. A statistically significant correlation was noted between the amounts of improvement and length of follow-up for URI patients. Thirteen of these patients also reported improved olfactory function.
  
  
  CONCLUSIONS
  These findings for patients with head trauma are consistent with other reports of recovery of (or improvement in) olfactory function after trauma-induced loss. For patients with previous URI, these data indicate that improvement in olfactory function occurs, but the improvement may take several years.
authors.affiliation: Department of Otolaryngology--Head and Neck Surgery, University of Cincinnati Medical Center, Ohio, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Duncan
authors.forename: A M
authors.initials: AM
authors.lastname: Seiden
mesh_terms: D000328:Adult; D003376:Counseling; D006259:Craniocerebral Trauma / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009812:Odorants; D000857:Olfaction Disorders / Q000209:etiology* / Q000503:physiopathology; D012075:Remission, Spontaneous; D015203:Reproducibility of Results; D012141:Respiratory Tract Infections / Q000150:complications*; D012903:Smell / Q000502:physiology