Prognostic value of olfactory evoked potentials in patients with post-infectious olfactory dysfunction

Purpose Prognostic assessment of patients with post-infectious olfactory dysfunction (PIOD) poses a challenge for clinicians. While there have been some studies on the prognostic factors of PIOD focusing on demographic factors, the aim of this study was to investigate whether event-related potentials (ERPs) could be used as a new predictor of olfactory recovery in PIOD. Methods This was a retrospective study involving patients who underwent olfactory examinations using Sniffin' Sticks test before treatment and after 1 year of follow-up. The responder group was defined by an increase of threshold-discrimination-identification (TDI) score of >= 6 points. All patients underwent ERP examination and the amplitude and latency of each wave of ERPs were recorded before treatment. Results A total of 61 patients (age 47.50 +/- 11.04 years, 27 males) were analyzed. The presence of olfactory ERPs (oERPs) was greater in the responder group than in the non-responder group (P = 0.007), while that of trigeminal ERPs (tERPs) did not differ between the two groups (P = 0.346). Logistic-regression analyses showed that factors associated with improvement of subjective olfactory function were duration (OR, 1.604; 95% CI, 1.062-2.423; P = 0.025), initial threshold (odds ratio [OR], 0.043; 95% confidence interval [CI], 0.004-0.439; P = 0.008), and latency of N1 in oERPs (OR, 1.007; 95% CI, 1.001-1.013; P = 0.021). Conclusion Our study shows that duration of OD, initial threshold, and latency of N1 in oERPs were associated with olfactory improvement in PIOD patients, which may provide guidance for clinicians.

Automated summary

This study showed that event-related potentials (ERPs), duration of olfactory dysfunction (OD), and initial threshold were associated with olfactory improvement in patients with post-infectious olfactory dysfunction (PIOD). These findings may provide guidance for clinicians in developing more effective treatment plans.