People who experience even a mild concussion are likely to have impaired olfactory function 24 hours later and may experience associated anxiety problems a year later, a study in the journal Brain Injury suggests.
The cross-sectional study evaluated olfaction 24 hours (baseline) in 20 patients after a first-time mild traumatic brain injury (TBI) and 22 patients after orthopaedic injury (limb fracture), and at one-year follow-up (n=12 mild TBI, n=7 orthopaedic controls). The researchers further evaluated the influence of the cognition and affective state on olfactory function.
At baseline, patients with mild TBI demonstrated significantly reduced olfactory function, compared to controls, with 55 per cent (n=11) of the mild TBI patients presenting signs of hyposmia, compared to 4.5 per cent of the controls (n=1).
One year later, no significant differences in olfactory scores between cases and controls were observed.
However, patients with mild TBI who had exhibited hyposmia at baseline exhibited higher anxiety levels than patients with mild TBI with normal olfactory function, at baseline (P=.020) and at follow-up (P =.009), and more post-concussion symptoms at follow-up (P=.008).
Olfactory testing in the acute phase may therefore serve as a useful screening tool, but more research is needed, the researchers concluded.