Effectiveness of platelet-rich plasma in long-lasting post-viral olfactory dysfunction: a case-series.

OBJECTIVE: To investigate the platelet-rich plasma (PRP) effectiveness in patients with a long-lasting postviral olfactory dysfunction (LPOD). METHODS: Forty-three consecutive patients with a long-lasting postviral OD were prospectively recruited. The injection of 1 mL of PRP was carried out in both olfactory clefts. The pre- to 6-month post-PRP injection change in olfaction was assessed with the olfactory disorder questionnaire (ODQ) and the threshold, discrimination, and identification (TDI) tests. RESULTS: Forty-three patients received bilateral PRP injections (24 females). The mean age of patients was 58.9 ± 16.8 years. The mean duration of LPOD was 8.7 years. The pre to 6-month post-injection mean TDI significantly improved from 10.3 ± 10.2 to 20.12 ± 12.07 (p = 0.001). The mean ODQ significantly decreased from 29.8 ± 13.0 to 23.4 ± 11.3 (p = 0.013). The average change of the TDI and the ODQ were 9.8 and 6.4, respectively. Age was inversely associated with the 6-month threshold score. CONCLUSION: PRP appears to be a promising therapeutic strategy for long-lasting postviral OD. Our findings support the conduction of controlled randomized trial in this population of patients.

Validity and Reliability of the Reflux Sign Assessment-10 (RSA-10).

OBJECTIVE: To develop and validate the Reflux Sign Assessment-10 (RSA-10) for documenting the physical findings of laryngopharyngeal reflux disease (LPRD). METHODS: Patients with LPRD at the hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring and asymptomatic individuals were consecutively recruited from two European hospitals. Three experienced otolaryngologists rated RSA-10 in patients and controls for assessing internal validity. RSA-10 was rated within a 7-day period to assess test-retest reliability. Internal consistency was measured using Cronbach's α in patients and controls. Convergent validity was evaluated through a correlation analysis between RSA-10 and Reflux Finding Score (RFS). Interrater reliability was evaluated by comparing the RSA-10 evaluations of the three otolaryngologists through Fleiss kappa. Pre- to posttreatment change of RSA-10 was evaluated to assess responsiveness to change. The RSA-10 thresholds were examined by receiver operating characteristic analysis. RESULTS: Fifty-five patients completed the pre- to posttreatment evaluations from January 2020 to December 2023. A total of 115 asymptomatic individuals completed the study. RSA-10 reported high internal consistency reliability (α = 0.822) and test-retest reliability (rs = 0.725). The RSA-10 scores of patients were significantly higher than those of controls (p = 0.001), suggesting high internal validity. RSA-10 was significantly correlated with the RFS (rs = 0.771). The interrater reliability was adequate for sub- and total RSA-10 scores (k = 0.708). RSA-10 significantly improved from baseline to 3-month posttreatment (p = 0.001). An RSA-10 > 13 may be suggestive of LPRD. Both RSA-10 > 13 and Reflux Symptom Score-12 > 11 were associated with a sensitivity of 92.7% and a specificity of 97.3%. CONCLUSION: The RSA-10 is a reliable and valid clinical instrument for documenting the most prevalent laryngeal and extra-laryngeal findings associated with LPRD. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Digestive Biomarkers of Laryngopharyngeal Reflux: A Preliminary Prospective Controlled Study.

OBJECTIVE: To investigate the digestive enzymes and biomarkers in the saliva of patients with laryngopharyngeal reflux (LPR) and asymptomatic individuals. STUDY DESIGN: Prospective controlled study. SETTING: Multicenter study. METHODS: Patients with LPR at the hypopharyngeal-esophageal impedance-pH monitoring (HEMII-pH) and asymptomatic individuals were consecutively recruited from January 2020 to April 2023 from 2 University Hospitals. The saliva of patients (off PPIs) and asymptomatic individuals was collected to measure pH, elastase, bile salts, cholesterol, gastric, and pancreatic lipases. Anxiety, symptoms, and findings were studied through perceived stress scale (PSS), reflux symptom score (RSS), and reflux sign assessment (RSA). RESULTS: Sixty-seven LPR patients and 57 asymptomatic individuals completed the evaluations. LPR patients reported higher PSS, RSS, and RSA than asymptomatic individuals. The mean saliva pH was more alkaline in LPR patients (7.23: 95% confidence interval [CI]: 7.08, 7.38) compared to controls (6.13; 95% CI: 5.95, 6.31; P = .001). The mean concentration of elastase was higher in patients (51.65 µg/mL; 95% CI: 44.47, 58.83 µg/mL) versus asymptomatic individuals (25.18 µg/mL; 95% CI: 21.64, 28.72 µg/mL; P = .001). The saliva cholesterol reported higher concentration in healthy individuals (3.43 mg/dL; 95% CI: 3.21, 3.65 mg/dL) compared to patients (1.16 mg/dL; 95% CI: 1.05, 1.27 mg/dL; P = .001). The saliva pH, and elastase concentration were significantly associated with the baseline RSS, while saliva cholesterol was negatively associated with the severity of RSS and RSA. CONCLUSION: Cholesterol, bile salts, and elastase are biomarkers of LPR and should be considered to develop future non-invasive saliva device for the detection of LPR.

ATP1A1 is a promising new target for melanoma treatment and can be inhibited by its physiological ligand bufalin to restore targeted therapy efficacy.

Despite advancements in treating metastatic melanoma, many patients exhibit resistance to targeted therapies. Our study focuses on ATP1A1, a sodium pump subunit associated with cancer development. We aimed to assess ATP1A1 prognostic value in melanoma patients and examine the impact of its ligand, bufalin, on melanoma cell lines in vitro and in vivo. High ATP1A1 expression (IHC) correlated with reduced overall survival in melanoma patients. Resistance to BRAF inhibitor was linked to elevated ATP1A1 levels in patient biopsies (IHC, qPCR) and cell lines (Western blot, qPCR). Additionally, high ATP1A1 mRNA expression positively correlated with differentiation/pigmentation markers based on data from The Cancer Genome Atlas (TCGA) databases and Verfaillie proliferative gene signature analysis. Bufalin specifically targeted ATP1A1 in caveolae, (proximity ligation assay) and influenced Src phosphorylation (Western blot), thereby disrupting multiple signaling pathways (phosphokinase array). In vitro, bufalin induced apoptosis in melanoma cell lines by acting on ATP1A1 (siRNA experiments) and, in vivo, significantly impeded melanoma growth using a nude mouse xenograft model with continuous bufalin delivery via an osmotic pump. In conclusion, our study demonstrates that ATP1A1 could serve as a prognostic marker for patient survival and a predictive marker for response to BRAF inhibitor therapy. By targeting ATP1A1, bufalin inhibited cell proliferation, induced apoptosis in vitro, and effectively suppressed tumor development in mice. Thus, our findings strongly support ATP1A1 as a promising therapeutic target, with bufalin as a potential agent to disrupt its tumor-promoting activity.

Mucosal antibody response and SARS-CoV-2 shedding in patients with COVID-19 related olfactory dysfunction.

Olfactory dysfunction (OD) was one of the most common symptom of infection with the Wuhan strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and could persist for several months after symptom onset. The pathogenesis of prolonged OD remains poorly understood but probably involves sustained viral replication associated with limited mucosal immune response to the virus. This prospective study was conducted to investigate the potential relationship between nasal SARS-CoV-2 viral load and antibody levels in patients with loss of smell. One hundred and five patients were recruited 2 weeks after presenting with confirmed coronavirus disease 2019 associated OD. Based on the identification sniffing test performed at enrollment, 52 patients were still anosmic or hyposmic and 53 were normosmic. SARS-CoV-2 was detectable in nasal wash of about 50% of anosmic and normosmic patients. Higher viral load was detected in anosmic patients with lower levels of SARS-CoV-2 specific nasal immunoglobulins (Ig) IgG and IgA. This association was not observed in normosmic patients. No relationship between nasal viral load and antibodies to endemic coronaviruses was observed. SARS-CoV-2 replication in the nasal cavity may be promoted by defective mucosal antibody responses in patients with OD. Boosting mucosal immunity may limit nasal SARS-CoV-2 replication and thereby help in the control of persistent OD.

Effectiveness of Platelet-Rich Plasma for COVID-19-Related Olfactory Dysfunction: A Controlled Study.

OBJECTIVE: To investigate the effectiveness of platelet-rich plasma (PRP) injection into the olfactory clefts of coronavirus disease 2019 (COVID-19) patients with persistent olfactory dysfunction (OD). STUDY DESIGN: Controlled study. SETTING: Multicenter study. METHODS: From March 2022 to November 2022, COVID-19 patients with persistent OD were recruited from three European hospitals to undergo PRP injections into the olfactory clefts. Olfactory function was evaluated at baseline and 10 weeks postinjection with the Olfactory Disorder Questionnaire (ODQ) and threshold, discrimination, and identification (TDI) test. Data were compared with a control group of untreated patients. RESULTS: Eighty-one patients who underwent PRP injection and 78 controls were included. Sixty-five PRP patients (80.3%) experienced subjective smell improvement after a mean duration of 3.4 ± 1.9 weeks. The parosmia, life quality statement, and ODQ sub- and total scores significantly decreased from pre- to 10-week postinjection in the PRP group. The TDI sub- and total scores significantly increased 10 weeks postinjection. In controls, the ODQ score did not change over time, while the discrimination, identification, and total TDI scores significantly increase after 10 weeks of follow-up. The 10-week TDI and ODQ scores were significantly better in the PRP group compared with the controls. CONCLUSION: Patients who underwent PRP injection reported better 10-week subjective and objective smell outcomes than controls. Future randomized-controlled studies using saline injection into the olfactory cleft of controls are needed to determine the superiority of PRP over placebo.

The Dubai Definition and Diagnostic Criteria of Laryngopharyngeal Reflux: The IFOS Consensus.

OBJECTIVE: The objective of this work was to gather an international consensus group to propose a global definition and diagnostic approach of laryngopharyngeal reflux (LPR) to guide primary care and specialist physicians in the management of LPR. METHODS: Forty-eight international experts (otolaryngologists, gastroenterologists, surgeons, and physiologists) were included in a modified Delphi process to revise 48 statements about definition, clinical presentation, and diagnostic approaches to LPR. Three voting rounds determined a consensus statement to be acceptable when 80% of experts agreed with a rating of at least 8/10. Votes were anonymous and the analyses of voting rounds were performed by an independent statistician. RESULTS: After the third round, 79.2% of statements (N = 38/48) were approved. LPR was defined as a disease of the upper aerodigestive tract resulting from the direct and/or indirect effects of gastroduodenal content reflux, inducing morphological and/or neurological changes in the upper aerodigestive tract. LPR is associated with recognized non-specific laryngeal and extra-laryngeal symptoms and signs that can be evaluated with validated patient-reported outcome questionnaires and clinical instruments. The hypopharyngeal-esophageal multichannel intraluminal impedance-pH testing can suggest the diagnosis of LPR when there is >1 acid, weakly acid or nonacid hypopharyngeal reflux event in 24 h. CONCLUSION: A global consensus definition for LPR is presented to improve detection and diagnosis of the disease for otolaryngologists, pulmonologists, gastroenterologists, surgeons, and primary care practitioners. The approved statements are offered to improve collaborative research by adopting common and validated diagnostic approaches to LPR. LEVEL OF EVIDENCE: 5 Laryngoscope, 134:1614-1624, 2024.

Preventive and Therapeutic Effect of Metformin in Head and Neck Cancer: A Concise Review.

BACKGROUND: Head and neck cancer (HNC) is a complex affection. Nowadays, conventional treatments are associated with many side effects, reducing the patient's quality of life. Recent studies suggest that metformin, a first-line treatment for diabetes, could decrease cancer incidence and improve cancer-related survival rates. METHODS: This systematic review summarizes important data from studies evaluating metformin's contribution to preventing and treating HNC. RESULTS: The results suggest a protective effect of metformin in HNC. However, no consensus has been found on its therapeutic effects. Metformin seems to confer an improved cancer-related survival rate in a diabetic population, but compared to a non-diabetic population, the review could not identify any advantages. Nevertheless, no studies presented a negative impact. CONCLUSION: In conclusion, the results of this systematic review suggest that HNC patients may benefit from metformin. Indeed, it would reduce the HNC incidence. However, more studies are required to evaluate the effect on cancer-related survival rates.

Macrophage Profiling in Head and Neck Cancer to Improve Patient Prognosis and Assessment of Cancer Cell-Macrophage Interactions Using Three-Dimensional Coculture Models.

Tumor-associated macrophages are key components of the tumor microenvironment and play important roles in the progression of head and neck cancer, leading to the development of effective strategies targeting immune cells in tumors. Our study demonstrated the prognostic potential of a new scoring system (Macroscore) based on the combination of the ratio and the sum of the high and low densities of M1 (CD80+) and M2 (CD163+) macrophages in a series of head and neck cancer patients, including a training population (n = 54) and a validation population (n = 19). Interestingly, the Macroscore outperformed TNM criteria and p16 status, showing a significant association with poor patient prognosis, and demonstrated significant predictive value for overall survival. Additionally, 3D coculture spheroids were established to analyze the crosstalk between cancer cells and monocytes/macrophages. Our data revealed that cancer cells can induce monocyte differentiation into protumoral M2 macrophages, creating an immunosuppressive microenvironment. This coculture also induced the production of immunosuppressive cytokines, such as IL10 and IL8, known to promote M2 polarization. Finally, we validated the ability of the macrophage subpopulations to induce apoptosis (M1) or support proliferation (M2) of cancer cells. Overall, our research highlights the potential of the Macroscore as a valuable prognostic biomarker to enhance the clinical management of patients and underscores the relevance of a spheroid model in gaining a better understanding of the mechanisms underlying cancer cell-macrophage interactions.

Effect of the Size and Shape of Dendronized Iron Oxide Nanoparticles Bearing a Targeting Ligand on MRI, Magnetic Hyperthermia, and Photothermia Properties-From Suspension to In Vitro Studies.

Functionalized iron oxide nanoparticles (IONPs) are increasingly being designed as a theranostic nanoplatform combining specific targeting, diagnosis by magnetic resonance imaging (MRI), and multimodal therapy by hyperthermia. The effect of the size and the shape of IONPs is of tremendous importance to develop theranostic nanoobjects displaying efficient MRI contrast agents and hyperthermia agent via the combination of magnetic hyperthermia (MH) and/or photothermia (PTT). Another key parameter is that the amount of accumulation of IONPs in cancerous cells is sufficiently high, which often requires the grafting of specific targeting ligands (TLs). Herein, IONPs with nanoplate and nanocube shapes, which are promising to combine magnetic hyperthermia (MH) and photothermia (PTT), were synthesized by the thermal decomposition method and coated with a designed dendron molecule to ensure their biocompatibility and colloidal stability in suspension. Then, the efficiency of these dendronized IONPs as contrast agents (CAs) for MRI and their ability to heat via MH or PTT were investigated. The 22 nm nanospheres and the 19 nm nanocubes presented the most promising theranostic properties (respectively, r2 = 416 s-1·mM-1, SARMH = 580 W·g-1, SARPTT = 800 W·g-1; and r2 = 407 s-1·mM-1, SARMH = 899 W·g-1, SARPTT = 300 W·g-1). MH experiments have proven that the heating power mainly originates from Brownian relaxation and that SAR values can remain high if IONPs are prealigned with a magnet. This raises hope that heating will maintain efficient even in a confined environment, such as in cells or in tumors. Preliminary in vitro MH and PTT experiments have shown the promising effect of the cubic shaped IONPs, even though the experiments should be repeated with an improved set-up. Finally, the grafting of a specific peptide (P22) as a TL for head and neck cancers (HNCs) has shown the positive impact of the TL to enhance IONP accumulation in cells.

Comparison of prevalence and evolution of COVID-19 olfactory disorders in patients infected by D614 (wild) and B.1.1.7. Alpha variant: a brief report.

OBJECTIVES: To investigate the prevalence and the evolution of olfactory disorders (OD) related to coronavirus disease 2019 (COVID-19) in patients infected during the first and the second European waves. METHODS: From March 2020 to October 2020, COVID-19 patients with OD were recruited and followed over the 12-month post-infection. The following data were collected: demographic, treatments, vaccination status, and olfactory function. Olfaction was assessed with the Olfactory Disorder Questionnaire (ODQ), and threshold, discrimination, and identification (TDI) test. Outcomes were compared between patients of the first wave (group 1: wild/D614G virus) and the second wave (group 2: B.1.1.7. Alpha variant) at 1-, 3- and 12-month post-infection. RESULTS: Sixty patients completed the evaluations accounting for 33 and 27 patients in group 1 and 2, respectively. The 1-month TDI score (23.7 ± 5.3) was significantly lower in group 2 compared to group 1 (29.8 ± 8.7; p = 0.017). Proportion of normosmic patients at 1-month post-infection was significantly higher in group 1 compared to group 2 (p = 0.009). TDI scores only significantly increased from 1- to 3-month post-infection in anosmic and hyposmic patients. Focusing on There was a negative association between the 1-month ODQ and the 1-month TDI (rs = - 0.493; p = 0.012). ODQ was a significant predictor of TDI scores at 3- and 12-month post-infection. The 12-month prevalence of parosmia was 60.6% in group 1 and 42.4% in group 2, respectively. There was no significant influence of oral corticosteroid treatment, adherence to an olfactory training and vaccination status on the olfactory outcomes. CONCLUSIONS: Patients of the second wave (Alpha B.1.1.7. variant) reported significant higher proportion of psychophysical test abnormalities at 1-month post-infection than patients infected during the first wave (D614G virus).

Association between laryngopharyngeal reflux, gastroesophageal reflux and recalcitrant chronic rhinosinusitis: A systematic review.

OBJECTIVE: To investigate the association between laryngopharyngeal reflux (LPR), gastroesophageal reflux disease (GERD) and recalcitrant chronic rhinosinusitis (CRS). DATA SOURCES: PubMed, Cochrane Library and Scopus. REVIEW METHODS: Three investigators searched the specified databases for studies investigating the relationship between LPR, GERD and recalcitrant CRS with or without polyposis. The following outcomes were investigated with PRISMA criteria: age; gender; reflux and CRS diagnosis; association outcomes and potential treatment outcomes. The authors performed a bias analysis of papers and provided recommendations for future studies. RESULTS: A total of 17 studies investigated the association between reflux and recalcitrant CRS. According to pharyngeal pH monitoring, 54% of patients with recalcitrant CRS reported hypo or nasopharyngeal acid reflux events. The number of hypo- and nasopharyngeal acid reflux events was significantly higher in patients compared to healthy individuals in 4 and 2 studies, respectively. Only one study did not report intergroup differences. The proportion of GERD was significantly higher in CRS patients compared to controls, with a prevalence ranging from 32% to 91% of cases. No author considered nonacid reflux events. There was significant heterogeneity in the inclusion criteria; definition of reflux and association outcomes, limiting the ability to draw clear conclusions. Pepsin was found in sinonasal secretions more frequently in CRS patients than controls. CONCLUSION: Laryngopharyngeal reflux and GERD may be contributing factors of CRS therapeutic resistance, but future studies are needed to confirm the association considering nonacid reflux events.

Therapies for COVID-19-Related Persistent Olfactory Disorders: One of the Good Fruits of the Pandemic.

At the beginning of 2021, the scientific community realized the burden of COVID-19-related persistent olfactory disorders (ODs). The percentage of those infected with COVID-19 who developed severe and persistent ODs [1-3] with devastating effects on their quality of life was 5 to 40% [4,5].

Bioconjugation studies of an EGF-R targeting ligand on dendronized iron oxide nanoparticles to target head and neck cancer cells.

A major challenge in nanomedicine is designing nanoplatforms (NPFs) to selectively target abnormal cells to ensure early diagnosis and targeted therapy. Among developed NPFs, iron oxide nanoparticles (IONPs) are good MRI contrast agents and can be used for therapy by hyperthermia and as radio-sensitizing agents. Active targeting is a promising method for selective IONPs accumulation in cancer tissues and is generally performed by using targeting ligands (TL). Here, a TL specific for the epidermal growth factor receptor (EGFR) is bound to the surface of dendronized IONPs to produce nanostructures able to specifically recognize EGFR-positive FaDu and 93-Vu head and neck cancer cell lines. Several parameters were optimized to ensure a high coupling yield and to adequately quantify the amount of TL per nanoparticle. Nanostructures with variable amounts of TL on the surface were produced and evaluated for their potential to specifically target and be thereafter internalized by cells. Compared to the bare NPs, the presence of the TL at the surface was shown to be effective to enhance their internalization and to play a role in the total amount of iron present per cell.

Usefulness, acceptation and feasibility of electronic medical history tool in reflux disease.

OBJECTIVES: To investigate usefulness, feasibility, and patient satisfaction of an electronic pre-consultation medical history tool (EPMH) in laryngopharyngeal reflux (LPR) work-up. METHODS: Seventy-five patients with LPR were invited to complete electronic medical history assessment prior to laryngology consultation. EPMH collected the following parameters: demographic and epidemiological data, medication, medical and surgical histories, diet habits, stress and symptom findings. Stress and symptoms were assessed with perceived stress scale and reflux symptom score. Duration of consultation, acceptance, and satisfaction of patients (feasibility, usefulness, effectiveness, understanding of questions) were evaluated through a 9-item patient-reported outcome questionnaire. RESULTS: Seventy patients completed the evaluation (93% participation rate). The mean age of cohort was 51.2 ± 15.6 years old. There were 35 females and 35 males. Patients who refused to participate (N = 5) were > 65 years old. The consultation duration was significantly lower in patients who used the EPMH (11.3 ± 2.7 min) compared with a control group (18.1 ± 5.1 min; p = 0.001). Ninety percent of patients were satisfied about EPMH easiness and usefulness, while 97.1% thought that EPMH may improve the disease management. Patients would recommend similar approach for otolaryngological or other specialty consultations in 98.6% and 92.8% of cases, respectively. CONCLUSION: The use of EPMH is associated with adequate usefulness, feasibility, and satisfaction outcomes in patients with LPR. This software is a preliminary step in the development of an AI-based diagnostic decision support tool to help laryngologists in their daily practice. Future randomized controlled studies are needed to investigate the gain of similar approaches on the traditional consultation format.

Platelet-rich plasma injection in the olfactory clefts of COVID-19 patients with long-term olfactory dysfunction.

OBJECTIVE: To investigate safety, feasibility, and effectiveness of platelet-rich plasma (PRP) injection into the olfactory clefts of COVID-19 patients with persistent olfactory dysfunction (OD). METHODS: From March 2022 to July 2022, COVID-19 patients with persistent OD were consecutively recruited to benefit from PRP injection into the olfactory clefts. Patient pain, annoyance, time of procedure, and adverse events were evaluated. Olfactory function was evaluated at baseline and 2-month post-injection with the olfactory disorder questionnaire (ODQ) and threshold, discrimination, and identification (TDI) test. RESULTS: Eighty-seven patients with anosmia (N = 30), hyposmia (N = 40), or parosmia (N = 17) with a mean OD duration of 15.7 months completed the evaluations. The PRP injection was successfully performed in all patients with a mean procedure time of 18.4 ± 3.4 min. The adverse events included transient epistaxis (N = 31), parosmia related to xylocaine spray (N = 10), and vasovagal episode (N = 2). The injection procedure was evaluated as somewhat or moderately painful by 41 (47%) and 22 (25%) patients, respectively. Thirty-seven patients were assessed after 2 months post-injection. The mean ODQ and TDI scores significantly improved from baseline to 2-month post-injection (p < 0.01). The olfactory improvement occurred after a mean of 3.6 ± 1.9 weeks. CONCLUSION: The injection of PRP into the olfactory clefts is safe and associated with adequate patient-reported outcomes. The findings of this preliminary study suggest possible efficacy on subjective and psychophysical evaluations, but future randomized controlled studies are needed to determine the superiority of PRP injection over placebo.

Effectiveness of olfactory training in COVID-19 patients with olfactory dysfunction: a prospective study.

OBJECTIVES: To investigate effectiveness of olfactory training (OT) in COVID-19 patients with persistent olfactory dysfunction (OD). METHODS: From March 2020 to March 2022, COVID-19 patients with OD were prospectively followed in three European medical centers for a period of 18 months. A standardized OT protocol were recommended to patients. Patient-reported outcome questionnaires and psychophysical evaluations were used to evaluate olfaction at baseline, 6, 12, and 18 months after the start of OT. The evolution of olfactory outcome was compared according to the adherence to the OT protocol. RESULTS: Fifty-seven patients completed the evaluations. Thirty-two patients fully adhered to the OT, while 25 did not adhere. The psychophysical scores significantly improved from baseline to 6-month post-infection in both groups. In the OT group, the psychophysical scores continued to significantly improve from 6 to 12 months after the start of OT (p = 0.032). The mean duration of OT was 15.4 weeks. The mean delay of patient recovery perception was comparable between groups (27.4 weeks). The occurrence of cacosmia (35.1%) and parosmia (43.9%) throughout the follow-up period was comparable between groups. There proportion of phantosmia was higher in training (34.4%) compared with no-OT (16.0%; p = 0.007) group. The baseline Sniffin'Sticks tests was positively associated with the 6-month Sniffin'Sticks tests (rs = 0.685; p < 0.001) and negatively associated with the time of recovery (rs = - 0.369; p = 0.034). CONCLUSIONS: The adherence to an OT protocol was associated with better mid-term improvement of psychophysical scores. Future large-cohort randomized-controlled studies are needed to confirm the effectiveness of OT in COVID-19 patients.