Assessment of olfactory function after traumatic brain injury: comparison of single odour tool with detailed assessment tool

Objectives: Olfactory disturbance (OD) is common after traumatic brain injury (TBI). Screening for OD can be performed by several different methods. While odour identification tools are considered more accurate, they are time consuming. The predominant method in clinical practice remains the use of a single odour. This study aimed to compare a brief single-odour identification tool (BSOIT) with a more detailed 12-odour assessment tool.Materials/Methods: One hundred seventy consecutive patients with TBI had their olfaction assessed using BSOIT and a 12-item tool at a single time point. The sensitivity and specificity of the BSOIT were calculated.Results: The sensitivity and specificity of the BSOIT as compared to the Burghart tool were 57.5% and 100%, respectively, for all ODs (anosmia and hyposmia). The sensitivity and specificity for anosmia only were 93.5% and 96.7%, respectively. For the two tools, the Cohen's kappa coefficient showed moderate agreement when both anosmia and hyposmia were considered (k=0.619, p<0.001) but a very strong agreement when only anosmia was considered (k=0.844, p<0.001).For both the tools, anosmia had a significant association with TBI severity (p<0.001). However, hyposmia showed no such association.Conclusions: The BSOIT is very effective at identifying anosmia but not hyposmia, producing comparable results to a more detailed test. It can be effective in clinical practice and takes considerably less time.