Olfactory Testing Informs the Decision Process to Obtain Advanced Neuroimaging in Traumatic Brain Injury

The purpose of this article is to examine the usefulness of olfactory testing as a tool for the evaluation or stratification of traumatic brain injury (TBI) patients. Olfactory dysfunction is more likely to be overlooked by both the patient and the provider, especially in the acute setting, in contrast to deficits in other senses like vision or hearing. This is a retrospective clinical analysis (case series) of eight active duty service members referred to ear, nose, and throat clinic at Walter Reed National Military Medical Center during a 2-yr period between March 2014 and March 2016 for subspecialist evaluation of suspected olfactory impairment after an exposure to closed head trauma. Advanced neuroimaging revealed evidence of frontal lobe injury in all eight patients, which was subtle and subcentimeter in half of the cases, best demonstrated with high-resolution imaging in the coronal plane. In this article, we discuss the correlation between olfactory dysfunction and brain pathology in both TBI and non-TBI settings. We then provide our recommendation for an orbit magnetic resonance imaging (MRI) to evaluate the inferior frontal lobes and olfactory bulbs in patients with unexplained anosmia.