To investigate changes of olfactory bulb (OB) volume over time in relation to olfactory function.
Prospective, before-after trial.
Outpatient clinic of a university clinic for otorhinolaryngology.
A total of 20 patients with olfactory loss participated in the study. The duration of olfactory deficits ranged from 3 months to 6 years.
Main Outcome Measures
Olfactory function was assessed for phenyl ethyl alcohol odor threshold, odor discrimination, and odor identification. Olfactory bulb volume was determined using magnetic resonance imaging.
In initially hyposmic patients (n = 13), changes in OB volume were found to correlate with odor threshold changes (r = 0.82; P = .001); no such correlation was found for odor discrimination or odor identification.
As demonstrated in a longitudinal study for the first time to our knowledge, the human OB is a highly plastic structure that responds to individual changes in olfactory status.