The Invisible Problem: The Incidence of Olfactory Impairment following Traumatic Brain Injury

Background and aims: As many as 50-60% of patients with traumatic brain injury (TBI) admitted to rehabilitation facilities may have olfactory impairment (OI). These incidence estimates are derived from studies conducted internationally and there is no comparable data available in the Australian context. The primary aim of this study was to identify the incidence of OI following TBI in a consecutive sample of adults admitted to the Epworth Hospital Brain Injury Rehabilitation Program in Victoria, Australia. A secondary aim was to investigate whether age, duration of posttraumatic amnesia (PTA) and presence of facial fractures made a significant contribution to the prediction of severity of OI. Method: The sample comprised 134 adults (mean age 39.09 years, SD 18.36), the majority of whom had sustained moderate to severe injury (PTA mean 21.57 days, SD 18.78). OI was measured using the Pocket Smell Test (PST) and the University of Pennsylvania Smell Identification Test (UPSIT). Results: Seventy-three participants (54.48%) demonstrated OI on the PST whereas 89 (66.42%) demonstrated OI on the UPSIT. Age, PTA duration, and presence of facial fractures predicted 10.3% of the variance in severity of OI. Conclusion: A substantial proportion of adults admitted for rehabilitation following TBI has OI. Accurate assessment and appropriate management of post-traumatic OI must be incorporated into rehabilitation programs.