Posttraumatic Anosmia and Ageusia : Incidence and Recovery with Relevance to the Hemorrhage and Fracture on the Frontal Base

Objective : We studied whether frontal skull base fracture has an impact on the occurrence and recovery of anosmia and/or ageusia following frontal traumatic brain injury (TBI). Methods : Between May 2003 and April 2005, 102 consecutive patients who had hemorrhage or contusion on the frontal lobe base were conservatively treated. Relevant clinical and radiographic data were collected, and assessment of impaired smell and taste sensation were also surveyed up to at least 12 months post-injury. Results : Among 102 patients, anosmia was noted in 22 (21.6%), of whom 10 had ageusia at a mean 4.4 days after trauma. Bilateral frontal lobe injuries were noted in 20 of 22 patients with anosmia and in all 10 patients with ageusia. Frontal skull base fracture was noted in 41 patients, of whom 9 (21.4%) had anosmia and 4 (9.5%) had ageusia. There was no statistical difference in the occurrence of anosmia and ageusia between patients with or without fracture. Of the 22 patients with anosmia, recovery from anosmia occurred in nine (40.9%) at the interval of 6 to 24 months after trauma, of whom six had frontal skull base fracture and three were not associated with fracture. Recovery of anosmia was significantly higher in patients without fracture than those with fracture (p<0.05). Recovery from ageusia occurred in only two of 10 patients at the interval of 18 to 20 months after trauma and was not eminent in patients without fracture. Conclusion : One should be alert and seek possibile occurrence of the anosmia and/or ageusia following frontal TBI. It is suggested that recovery is quite less likely if such patients have fractures on the frontal base, and these patients should wait for at least 6 to 18 months to anticipate such recovery if there is no injury to the central olfactory structures.