Assessment of individual odorant success rates in traumatic brain injury: key findings for clinical follow-up and olfactory rehabilitation

Objective Traumatic brain injury (TBI) is a leading cause of sensory morbidity, yet olfactory dysfunction is often underdiagnosed. This study aims to investigate the patterns of olfactory identification loss in TBI patients and evaluate the relationship between radiological findings and specific odorant deficits.Methods A total of 106 participants (53 TBI patients and 53 healthy controls) were included. Olfactory function was assessed using the Sniffin’ Sticks identification test. TBI patients were further evaluated with cranial CT and MRI to identify frontal bone fractures and intracranial pathologies (e.g. cortical contusions). Statistical analysis was performed to correlate trauma mechanisms and radiological data with olfactory scores.Results The mean olfactory identification score was significantly lower in the TBI group compared to controls (10.6 ± 3.1 vs. 13.8 ± 1.7, p < 0.001). Olfactory impairment was present in 54.7% of TBI patients (15.1% anosmia, 39.6% hyposmia). Cortical contusions (p < 0.001) and frontal fractures (p = 0.009) were strong predictors of lower scores. Notably, trigeminal-stimulating odors such as Lemon (81.1%) and Peppermint (79.2%) were better preserved compared to purely olfactory scents like Leather (37.7%) and Anise (41.5%). A strong negative correlation was found between intracranial pathology and identification success (r = -0.720, p < 0.001).Conclusion Olfactory identification deficits in TBI follow a specific pattern, where purely olfactory pathways are more susceptible to mechanical shearing injuries than trigeminal-stimulated pathways. The high prevalence of hyposmia suggests that standardized olfactory testing should be integrated into routine post-traumatic neurological assessments to facilitate early rehabilitation and improve quality of life.