Effects of pulsed and continuous ultrasound therapy on olfactory disorders in COVID-19 patients.

Background and Objectives: Olfactory dysfunction is common in COVID-19 patients, with a pooled prevalence of up to 50%. This study investigated the efficacy of pulsed and continuous ultrasound treatment on olfactory disorders of these patients. Materials and Methods: Three groups of COVID-19 patients having anosmia were studied, each including 15 patients. Pulsed ultrasound and continuous ultrasound were used to evaluate their efficacy on anosmia recovery in two groups of patients. The patients were subjected to pulsed or continuous ultrasound intervention 10 times during two weeks (5 days per week). The control group received no intervention. The SIT (Smell Identification Test) was used to assess the severity of olfactory dysfunctions of all patients on days 0 and 14. Data analysis was done using MANCOVA test. Results: Totally 20 (44.4%) and 25 (55.6%) patients were affected by Delta and Omicron variants of COVID-19 virus. The SIT test results showed a significant improvement in olfactory recovery of all 30 patients except one after ultrasound treatment (p < 0.05), but this was not observed in the control group. Pulsed and continuous ultrasound treatment showed an almost equal effect on olfaction status. Conclusion: Although there was no difference in olfactory test results in the control group during intervention period, pulsed and continuous ultrasound interventions were significantly effective in improving patients' olfaction. Pulsed and continuous therapeutic ultrasound improved the COVID-19 related olfactory dysfunction and can be considered as a promising technique for postinfectious olfaction.