Mild traumatic brain injury: evaluation of olfactory dysfunction and clinical-neurological characteristics

Objective: To evaluate olfactory function and clinical–neurological characteristics in a group of patients with mild head trauma. Methods: A total of 352 patients with MTBI underwent olfactory function evaluation. The site of head trauma, loss of consciousness <20 min, memory loss, subjective presence or absence of olfaction and other clinical, neurological and radiological aspects were evaluated and compared with the olfactory dysfunction. Results: A total of 33.5% patients enrolled in the study had an olfactory dysfunction. Eighty-seven percent of the patients had a diagnosis of anosmia whereas 13% had a diagnosis of hyposmia. Statistical analysis did not show a correlation between radiologically detected head lesions and different types of olfactory dysfunction (p > 0.05). Besides, no difference between head lesion site and different olfactory dysfunction was reported (p = 0.5). Regarding olfactory sub-tests a low detection threshold was present in these patients. Conclusion: The possibility of olfactory dysfunction should be considered in any case of MTBI appears differently than expected, a minor head injury causes anosmia much more frequently than hyposmia.