Previous studies have explored the quality of life (QoL) in people with olfactory dysfunction from various aetiologies. However, knowledge on QoL in people with post-traumatic brain injury (TBI) olfactory dysfunction is still limited. This study evaluates the impact of post-TBI olfactory dysfunction on QoL and determine factors influencing resultant QoL.

A case-control study conducted in a single centre on 30 TBI adults with olfactory dysfunction; matched by age and gender with 32 TBI controls having intact olfactory function. All 64 adults self-rated their olfactory function using a Visual Analogue Scale (VAS). Sniffin’ Sticks test was used as an objective olfactory function assessment and results measured as TDI (Threshold, Discrimination and Identification) score. QoL was determined by a self-rated questionnaire; Questionnaire for Olfactory Disorders (QOD). Influential factors evaluated include age, gender, employment, level of education, marital status, smoking habit, TBI-related clinical information and Disability Rating Scale (DRS) score. A correlation test between the VAS and natural log TDI was also conducted.

Mean QOD score of case group was significantly higher than control group (26.31±14.37 vs 9.44±8.30 respectively; P<0.001). After removing the effect of employment, smoking habit, co-morbidities, TBI duration and DRS score; there was a significant difference of mean QOD score between the two groups (F=16.426, P<0.001, η²=0.224). Calculated effect size was large with d=1.07 and odds ratio of 7.02. The most affected QoL domain was “perception of smell changes”. DRS score and olfactory function severity were factors influencing QoL (P<0.05). VAS score was positively correlated with natural log TDI score (r=0.433, P<0.05).

Individuals with post-TBI olfactory dysfunction are at higher risk of developing a lower QoL. One of the factors influencing this is the severity of olfactory dysfunction itself.