Loss of smell in patients with traumatic brain injury is associated with neuropsychiatric behavioral alterations.

Objective: We sought to identify and correlate the severity of traumatic brain injuries (TBIs) associated with olfactory dysfunction with cognitive and behavioral profiles.

Participants And Setting: Patients with TBI undergoing treatment in a specialized neuro-rehabilitation hospital.

Design: Prospective study.

Main Measures: Glasgow Coma Scale (GCS) at the time of injury and during posttraumatic amnesia. Motor functions were assessed with the Functional Instrument Measure and Disability Rating Scales. The Wechsler Adult Intelligence test was used for neuropsychologic assessment and the Neuropsychiatric Inventory was used to assess behavioral changes. The Barcelona Smell Test-24 was used to study subjective smell loss.

Results: A total of 111 patients with TBI were enrolled (33 females; mean age 32.86 years); 38.73% exhibited smell loss. Patients with no olfactory impairment (OI) had worse TBIs than those with OI (GCS scores 5.65 and 7.74, respectively); no significant differences in cognitive behaviors, such as attention memory, visuoperception, and visuoconstruction, were observed. However, patients with TBI and olfactory dysfunction showed statistically significant alterations in neuropsychiatric behavioral performances such as feeding when compared with patients with TBI without smell loss.

Conclusion: Olfactory dysfunction in patients with a TBI correlates with altered neuropsychiatric behavioral performances such as feeding, sleeping, and motor behavior.