Prognostic Factors for Olfactory Dysfunction in Adult Mild Head Trauma

Although posttraumatic olfactory disturbances are frequent, they have a poor prognosis. Our study aimed to investigate the impact of clinical factors on the progress of these olfactory disturbances.

Among patients admitted with evidence of head trauma, only suspected cases of posttraumatic olfactory disturbances were included. Patients were examined by the Sniffin'Sticks test, early posttraumatic and then later after recovery. Such factors as age, sex, olfactory bulb status, and observation period were enrolled in logistic regression analysis, because they are considered to have a possible influence on olfactory function improvements. Amelioration of olfaction was expressed as an alteration in olfactory function to a better level.

A total of 70 patients were involved, with a mean age of 38 years. The mean duration of follow-up was 6 months. Twelve patients (17.1%) had olfactory function improvements. In univariate and multivariate analyses, no clinical factors had an impact on olfactory recovery (all P > 0.05) except olfactory bulb integrity, which appears to influence improvement in olfactory function (P = 0.0327 and 0.0293).

Olfactory bulb integrity, probably the sole prognostic factor for posttraumatic olfactory recovery, where frank damage to such a structure carries a prognosis of poor posttraumatic olfactory function.