Olfactory and executive dysfunctions following orbito-basal lesions in traumatic brain injury

Objective: To study the acute relationship between olfactory function and traumatic brain injury (TBI), cognitive functions and outcome. Methods: Sixty-two patients with TBI were evaluated within the first 2 weeks following TBI. The Sniffin'Sticks identification test was used to assess olfaction. A neuropsychological evaluation was carried out to assess attention, verbal fluency, naming, memory, problem-solving and mental flexibility. The extended Glasgow Outcome Scale (GOSE) and the Disability Rating Scale (DRS) were rated at discharge from acute care. Results: Traumatic lesions located in the basal frontal area resulted in odour identification scores that were significantly lower than when lesions were elsewhere (p<0.001). A significant positive correlation was shown between odour identification scores and mental flexibility scores (p=0.004) and patients with hyposmia had worse performances on executive tests measuring problem-solving, verbal fluency and mental flexibility (p<0.01). Moreover, the odour identification score and the DRS total score were related (p=0.019). Conclusions: These findings add information regarding acute olfactory status following TBI and provide evidence on the importance of assessing olfaction very early post-TBI in order to plan intervention and determine what accident prevention advice will be required for home or work re-integration.