The Incidence of Anosmia After Traumatic Brain Injury: The SHEFBIT Cohort

Brain Inj. 2018;32(9):1122-1128. doi: 10.1080/02699052.2018.1483028. Epub 2018 Jun 6.


Background: While anosmia is common after Traumatic Brain Injury(TBI) (prevalence 4%-68%),studies differ in the associations found with other variables.

Aims: To assess the incidence of anosmia within a large, mixed TBI cohort and examine relationships with other injury or demographic features, including depression and global outcome(GOSE).

Design, subjects and setting: 774 consecutive TBI admissions over 2 years, assessed within a specialist neurorehabilitation clinic.

Methods: All patients assessed at 6-8 weeks and 1 year. Tools included the Extended Glasgow Outcome Scale(GOSE), Rivermead Head Injury Follow-up Questionnaire, Rivermead Post-Concussion Symptoms and the Hospital Anxiety and Depression Score. Olfactory function assessed with sensitivity to coffee granules.

Results: The overall incidence of anosmia was 19.7%; mild TBI (9.55%), moderate (20.01%), and severe (43.5%). On a logistic regression, features of TBI severity (p < 0.001 (95% CI 0.098-0.438)), medical comorbidities (p = 0.026 (95% CI 0.301-0.927)) and depression (p = 0.006 (95% CI 1.202-2.981)) were significant. Sixty percent of patients with anosmia at 1 year were found to be clinically depressed, compared to 36% of patients without anosmia.

Conclusion: In the largest prospective study of post-TBI anosmia, the incidence increased with TBI severity and other medical illness. The presence of anosmia should also raise the clinical suspicion of depression.

Keywords: TBI; anosmia; cohort; depression; severity.

MeSH terms

  • Brain Injuries, Traumatic / complications*
  • Brain Injuries, Traumatic / diagnostic imaging
  • Brain Injuries, Traumatic / epidemiology
  • Chi-Square Distribution
  • Cohort Studies
  • Depression / etiology
  • Female
  • Glasgow Outcome Scale
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Olfaction Disorders / diagnosis
  • Olfaction Disorders / epidemiology*
  • Olfaction Disorders / etiology*
  • Psychiatric Status Rating Scales
  • Tomography Scanners, X-Ray Computed