Improvement In Olfactory Function Research Articles

Structures and functions of the normal and injured human olfactory epithelium.

The olfactory epithelium (OE) is directly exposed to environmental agents entering the nasal cavity, leaving OSNs prone to injury and degeneration. The causes of olfactory dysfunction are diverse and include head trauma, neurodegenerative diseases, and aging, but the main causes are chronic rhinosinusitis (CRS) and viral infections. In CRS and viral infections, reduced airflow due to local inflammation, inflammatory cytokine production, release of degranulated proteins from eosinophils, and cell injury lead to decreased olfactory function. It is well known that injury-induced loss of mature OSNs in the adult OE causes massive regeneration of new OSNs within a few months through the proliferation and differentiation of progenitor basal cells that are subsequently incorporated into olfactory neural circuits. Although normal olfactory function returns after injury in most cases, prolonged olfactory impairment and lack of improvement in olfactory function in some cases poses a major clinical problem. Persistent inflammation or severe injury in the OE results in morphological changes in the OE and respiratory epithelium and decreases the number of mature OSNs, resulting in irreversible loss of olfactory function. In this review, we discuss the histological structure and distribution of the human OE, and the pathogenesis of olfactory dysfunction associated with CRS and viral infection.

Platelet-Rich Plasma (PRP) in the Treatment of Long COVID Olfactory Disorders: A Comprehensive Review.

Background: Long COVID has brought numerous challenges to healthcare, with olfactory dysfunction (OD) being a particularly distressing outcome for many patients. The persistent loss of smell significantly diminishes the affected individual's quality of life. Recent attention has been drawn to the potential of platelet-rich plasma (PRP) therapy as a treatment for OD. This comprehensive review aims to evaluate the effectiveness of PRP therapy in ameliorating OD, especially when associated with long-term COVID-19. Methods: We executed a comprehensive search of the literature, encompassing clinical trials and observational studies that utilized PRP in treating OD limited to COVID-19. We retrieved and comprehensively discussed data such as design, participant demographics, and reported outcomes, focusing on the efficacy and safety of PRP therapy for OD in COVID-19 patients. Results: Our comprehensive analysis interestingly found promising perspectives for PRP in OD following COVID-19 infection. The collective data indicate that PRP therapy contributed to a significant improvement in olfactory function after COVID-19 infection. Conclusions: The evidence amassed suggests that PRP is a promising and safe therapeutic option for OD, including cases attributable to Long COVID-19. The observed uniform enhancement of olfactory function in patients receiving PRP highlights the necessity for well-designed, controlled trials. Such studies would help to refine treatment protocols and more definitively ascertain the efficacy of PRP in a broader, more varied patient cohort.

Surgery for chronic rhinosinusitis with nasal polyps: An update

This update aimed to evaluate surgical indications in the management of chronic rhinosinusitis with nasal polyps (CRSwNP). It was conducted and reported according to the criteria stipulated by the Synthesis Without Meta-analysis (SwiM) guidelines. From the PubMed-National Library of Medicine database, 1098 articles were identified for the period 2006–2021 using the key words “nasal polyps” and “surgery”. After screening and analysis, 39 publications were selected. The efficacy of surgery on functional improvement in CRSwNP, measured by the specific quality-of-life score SNOT-22, is established, and improvement in olfactory function is expected in 50% of patients. The rate of surgical revision is at least 10–15% at 4 years, but the disease can be controlled for several years, with the interval between primary surgery and symptomatic recurrence exceeding 10 years in some cases. The criteria for surgery are not clearly defined in the literature. However, several authors consider failure of ≥ 8 weeks’ well-conducted local medical treatment and use of more than 2 courses of systemic corticosteroids as a reliable indication. No studies or meta-analyses are currently available to determine the superiority of one surgical technique over another.

Central Compartment Atopic Disease and Its Surgical Outcomes: Olfactory Changes and Technical Notes.

Central compartment atopic disease (CCAD) is a recent, novel phenotype of chronic rhinosinusitis. Only a few studies have assessed olfactory function in patients with CCAD. We aimed to investigate olfactory function changes after functional endoscopic sinus surgery (FESS) in patients with CCAD and proposed some surgical techniques to enhance the postoperative olfactory outcomes in such patients. A retrospective cohort study. We collected data from 23 patients (8 men and 15 women) with CCAD who underwent FESS performed by a surgeon in Taiwan, between June 2018 and December 2021. The demographic data, olfactory function, and serum and tissue eosinophil percentages of the included patients were analyzed. The Top International Biotech Smell Identification Test (TIBSIT; Top International Biotech, Taipei, Taiwan) was used to assess olfactory function. Of the 23 patients, most (95%) showed a positive reaction to aeroallergens, and 2 patients (8.7%) had asthma. Ten patients (43.5%) had peripheral eosinophilia, and 9 (39%) had eosinophilic nasal polyps. Moreover, the patients presented with variable olfactory dysfunction; the mean preoperative TIBSIT (pr-TIBSIT) score was 12.8 ± 2.3 (range: 0-43), whereas the mean postoperative TIBSIT (po-TIBSIT) score was 29.2 ± 1.9 (range: 16-44). The po-TIBSIT score was significantly better than the pre-TIBSIT score (paired t test, P < .0001). The improvement in olfactory function was not significantly correlated with the patients' age, serum eosinophil percentages, and nasal polyp eosinophil counts. Our findings indicate that CCAD is significantly associated with olfactory dysfunction and that FESS can effectively improve olfactory function. To optimize postoperative olfactory outcomes, precise removal of polyps from the olfactory cleft without damaging the neuroepithelium is recommended. Our study provides valuable insights into the management of CCAD patients undergoing FESS and can guide surgical decision-making to achieve optimal olfactory function outcomes.

Therapeutic options of post-COVID-19 related olfactory dysfunction: a systematic review and meta-analysis.

Olfactory dysfunction is a typical post-COVID-19 presentation, affecting patients' quality of life. There are currently multiple treatment options in this group of patients such as oral and intranasal corticosteroids, olfactory training, oral vitamin-mineral supplementation, amongst others. This meta-analysis aims to consolidate existing evidence for current therapies in patients with persistent olfactory dysfunction related to COVID-19 infection and evaluate the possible role of corticosteroid add-on therapy in olfactory training. A systematic review and meta-analysis to study current treatments/interventions for olfactory dysfunction in post-COVID-19 infection were conducted. Data were pooled for the meta-analysis. The outcomes include subjective or objective olfactory assessment major and minor adverse reactions. Eleven studies (1414 participants) were included in this review, with six studies (916 participants) then assessed for the meta-analysis. Combined treatment of intranasal corticosteroid (INCS) with olfactory training (OT) has no benefit over OT monotherapy from both a VAS score improvement and identification component of Sniffin' Sticks test standpoint. In addition, there were no differences in improvement of TDI score between combined oral corticosteroid (OCS) with OT therapy compared to OT alone. Olfactory function was, however, significantly improved after OT. There were no significant differences in the improvement of olfactory scores in combination INCS+OT or OCS+OT therapies compared to OT monotherapy. However, there is improvement in olfactory function after OT.

The effect of intra-nasal tetra sodium pyrophosphate on decreasing elevated nasal calcium and improving olfactory function post COVID-19: a randomized controlled trial

BackgroundOlfactory dysfunction is recognized as a symptom of COVID-19. Reports revealed the nasal calcium increase has adverse effects on olfactory function. Tetra sodium pyrophosphate, a chelating agent, can bind calcium and help improve olfaction.MethodsSixty-four patients with olfactory dysfunction persisting for more than 90 days after COVID-19 were recruited. Participants were divided into 2 groups that received either 0.9% sodium chloride or 1% tetra sodium pyrophosphate for topical application. Olfactory function was tested with the Sniffin' Sticks test before treatment and 1 month later. In addition, nasal calcium was determined with an ion-selective electrode.ResultsAfter topical application of tetra sodium pyrophosphate compared to sodium chloride, improvement from anosmia to hyposmia with decrease in calcium level was demonstrated. As for the results of tetra-sodium pyrophosphate, 81% showed improved olfactory function and 19% did not exhibit olfaction improvement.ConclusionsIntranasal application of tetra sodium pyrophosphate may be associated with improvement in olfactory function after COVID -19 infection.Trial registration Ethical Committee of Damietta Faculty of Medicine approved this study on January 2021 (approval number, IRB 00012367-21-03-010).

Mometasone Furoate in Non-Allergic Rhinitis: A Real-Life Italian Study

Background: In order to evaluate the efficacy of intranasal mometasone furoate in patients with non-allergic rhinitis (NAR), a real-life, observational, prospective study is performed. Methods: Thirty-one patients (age 18–64 years) receive intranasal (mometasone furoate, 200 µg b.i.d. for 15 consecutive days per month for 6 consecutive months), plus isotonic nasal saline. The cytologic pattern of local inflammation, nasal airflow, through peak nasal inspiratory flow (PNIF), quality of life (QoL), through the rhinitis quality of life questionnaire (RQLQ), the sinonasal outcome test (SNOT-22), the short-form 36-item health survey (SF-36v2), and the combined symptom medication score (CSMS), and, finally, olfactory function, through Sniffin’ sticks-16 identification test (SSIT-16), are evaluated at baseline and after treatment. Results: NARNE is the most frequent cytological pattern (48% of the total sample). The therapeutic response shows improvement in olfactory function and QoL. Conclusions: The results of this study confirm that intranasal mometasone furoate is an effective treatment for patients with NAR.

Symptoms of depression change with olfactory function

Olfactory loss is associated with symptoms of depression. The present study, conducted on a large cohort of mostly dysosmic patients, aimed to investigate whether improvement in olfactory performance would correspond with a decrease in depression severity. In 171 participants (157 dysosmic), we assessed olfactory function and severity of depression before and after an average interval of 11 months, with many patients showing improvement in olfactory function. Separate analyses were conducted for (a) the whole group of patients and (b) the group of dysosmic patients using both classic and Bayesian approaches. For odor identification, Student t test demonstrated that the whole sample improved consistently, especially within the group of dysosmic patients. The dysosmic group also improved in odor threshold and overall olfactory function. Pearson correlation showed that an increase in olfactory function was associated with a decrease in depression severity, particularly in dysosmic patients. To conclude, the present results indicate that symptoms of depression change with olfactory function in general and odor identification in particular.

Efficacy of olfactory training program in conjunction with nasal steroid irrigation in treating persistent smell loss in COVID-19 patients

Background: Smell loss is a challenging clinical problem. There is still no evidence-based medical intervention to treat patients with persistent smell loss as a result of Coronavirus Disease 2019 (COVID-19). The aim is to analyze the efficacy of treating patients with persistent smell loss due to COVID-19 using olfactory training (OT) combined with nasal steroid irrigation. Methods: A cross-sectional study enrolled 196 COVID-19 patients with persistent smell loss were recruited. All patients underwent two testing sessions. At the first session, patients were examined by a history taking followed by an Otorhinolaryngological examination including, a thorough nasal endoscopy. In addition, an olfactory performance assessment was performed to assess the severity of smell loss. All patients were then treated with OT and nasal steroid irrigation with budesonide for 12 weeks. The second session includes an olfactory performance assessment to assess if there is an improvement in olfactory function. Results: Patients after treatment showed improvement in overall Threshold-Detection-Identification (TDI) score, odor detection threshold score, odor discrimination score, and odor identification score, which were higher than before treatment. Statistically significant differences before and after treatment results were very pronounced for the overall TDI score (p = 0.014) and odor detection threshold score (p = 0.003). There was no significant difference in odor discrimination (p = 0.08) or odor identification (p = 0.126) scores before and after treatment. Conclusion: The results of this study support the efficacy of the combination of budesonide nasal irrigation and OT in treating persistent smell loss due to COVID-19 infection.

Prognostic value of olfactory bulb volume in patients with post-viral olfactory dysfunction

Objective:The purpose of this study was to compare the olfactory function examination results of patients with post-viral olfactory dysfunction（PVOD） in different prognostic groups and analyze prognostic factors, especially the influence of olfactory bulb volume（OBV） on prognosis, so as to provide objective basis for clinical diagnosis and treatment. Methods:After approval by the hospital ethics committee, the patients with PVOD admitted to Beijing Anzhen Hospital's outpatient department from January 2019 to December 2019 were followed up for at least 1 year. These patients completed the Sniffin' Sticks test and MRI examination of the olfactory pathway before treatment. According to the results of the Sniffin' Sticks test after 1 year follow-up（threshold-discrimination-identification（TDI） score of the patients was increased at least 6 points）, the patients were divided into two groups as the improvement group and the non-improvement group. The prognostic factors of PVOD patients were preliminarily determined by comparing the differences of various factors and the results of olfactory function examination between the two groups. Results:In this study, 47 patients with PVOD were included, with the smell improvement rate was 53.2%. Compared with the improvement group, the patients in the non-improvement group had longer duration, poorer initial olfactory function, higher olfactory threshold, and poorer olfactory discrimination and recognition ability（All P<0.01）. There was no statistical difference in terms of gender, age, allergic rhinitis and smoking between the two groups（All P>0.05）.The OBV of the non-improvement group was （59.48±23.92） mm³, which was significantly lower than that in the improvement group（[92.77±14.35]mm³, P<0.001）. Multiple logistic regression analysis showed that prognostic factors included course of disease（OR 0.677, 95%CI 0.461-0.993, P=0.046）, initial T value（OR 263.806, 95%CI 1.028-67 675.884, P=0.049） and OBV（OR 1.160, 95%CI 1.002-1.343, P=0.047）. The area under the receiver operating characteristic curve（ROC curve） of OBV was 0.888（0.797-0.979, P<0.001）. The correct diagnostic index of OBV≥78.50 mm³was used to determine the prognosis of olfactory function, with a specificity of 0.818 and a sensitivity of 0.840. The ROC curve analysis showed that the area under the ROC curve of duration was 0.822（0.703-0.940, P<0.001）. The correct diagnostic index of the duration ≤6 months was used to determine the prognosis of olfactory function, with a specificity of 0.727 and a sensitivity of 0.800. The area of T score was 0.793（0.662-0.924, P=0.001）. T score ≥1.25 was used as the correct diagnostic index to determine the prognosis of olfactory function. The specificity and sensitivity were 0.818 and 0.680, respectively. Conclusion:The prognosis of olfactory function in PVOD patients is related to the course of disease, the degree of olfactory loss and OBV. Those with no improvement in olfactory function have a longer disease course, aggravated olfactory damage and reduced OBV than those with improved olfactory function. The factors of Duration ≤6 months, T value ≥1.25 and OBV≥78.50 mm³suggested better prognosis, and the results of objective olfactory examination have greater value in evaluating the prognosis of olfactory function.

Stereotactic Radiosurgery for Olfactory Groove Meningiomas: An International, Multicenter Study.

Stereotactic radiosurgery (SRS) is increasingly considered for selected olfactory groove meningiomas (OGMs). To investigate the safety and efficacy of SRS for OGMs. From 20 institutions participating in the International Radiosurgery Research Foundation, we pooled patients who underwent SRS for histologically confirmed or radiologically suspected WHO grade I OGMs and were followed for 6 mo or more after the SRS. In total, 278 (median age 57 yr) patients underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) WHO grade I OGMs Median treatment volume was 4.60 cm3 (range: 0.12-27.3 cm3), median prescription dose was 12Gy, and median dose to the olfactory nerve was 11.20Gy. During median post-SRS imaging follow-up of 39 mo (range: 6-240 mo), 43% of patients had partial or marginal response, 54% of patients had stable disease, and 3% of patients experienced progression. During median post-SRS clinical follow-up of 51 mo (range: 6-240 mo), 36 (13%) patients experienced clinical and/or radiological adverse radiation events (AREs). Elevated risk of AREs was associated with larger OGM volume (P=.009) and pre-SRS peritumoral T2/fluid-attenuated inversion-recovery signal abnormalities (P<.001). After the SRS, olfaction remained stable, improved, or deteriorated in 90%, 8%, and 2% of patients, respectively. Complete post-SRS anosmia was predicted by partial/complete anosmia before the SRS (odds ratio [OR]=83.125; 95% CI [24.589-281.01], P<.001) and prior resection of OGM (OR=3.919; 95% CI [1.713-8.970], P=.001). SRS is associated with durable local control of the majority of OGM patients with acceptable safety profile. SRS allows preservation or improvement of olfactory function in the majority of OGM patients.

Adaptation of the Pediatric Smell WheelTM to evaluate olfactory function in Brazilian children

ObjectiveOlfaction influences nutrition, safety, and the cognitive development of children. Presently there are few olfactory tests for children, and normative reference values are generally lacking. In this study, we validate the Pediatric Smell WheelTM (PSW) to evaluate olfactory function in Brazilian children. MethodsWe modified and validated the PSW, a test developed in the United States, for administration in Brazil, and established normative data for Brazilian children. The validation process consisted of five phases. First, we identified odorants familiar to Brazilian children. Second, we established the test-retest reliability of the Brazilian PSW test that employed these odorants. Third, we compared the test scores of healthy children to those microsmic from adenoid hypertrophy. Fourth, we examined the test’s ability to detect improvement in olfactory function before and after adenoidectomy. Finally, we determined a normative 10th percentile cut point for defining microsmia in a sample of 169 healthy Brazilian children between 5 and 12 years of age. ResultsEleven odors were identified for inclusion in the test. The test-retest reliability was modest (r = 0.54, p < 0.001), although likely attenuated based on the inclusion of only data from children with normal function. The test clearly differentiated the olfactory function of children with adenoid hypertrophy from that of healthy children and demonstrated the return of function after adenoidectomy. An overall score <7 was found useful in defining hyposmia, although additional age-related cut-points were also defined. ConclusionA Brazilian version of the PSW was developed and validated and found to be efficacious in detecting smell dysfunction in children ranging in age from 5 to 12 years. Level of evidence1b (Diagnosis).

Bacterial biofilm in adults with ENT pathology

Introduction. Chronic rhinosinusitis, a very common inflammatory condition, is a main public health issue affecting the quality of life. Furthermore, some patients do not respond to either medical or surgical intervention, which could be explained by the presence of the bacterial biofilm in the rhinosinusal zone. Objectives. The aim of this study is to evaluate the influence of endoscopic sinus surgery on olfactory impairment caused by chronic sinusitis with and without nasal polyps (CRSNP and CRS), by testing the olfactory function and potential dysfunction before and after endoscopic sinus surgery. Another objective is to find a connection between the percentage of coverage with bacterial biofilm of the nasal mucosa from patients with CRSNP and CRS and to evidence the fountain of infection role of the bacterial biofilm, while demonstrating that antibiotic therapy is not efficient once the bacterial biofilm is formed in the nasal sinuses. Materials and methods. We investigated 123 patients with CRSNP and CRS, which underwent functional endoscopic sinus surgery (FESS). The olfactory function was tested pre and post FESS. We also analyzed and compared the scores of endoscopic images of Lund-Kennedy and CT staging scale of LundMackey for the two study groups. The degree of olfactory rehabilitation in patients with CRSNP and CRS was evaluated performing smell diskettes test. The presence of bacterial biofilm on the surface of the nasal mucosa extracted during FESS from patients with CRSNP and CRS was examined with the electronic microscope and the percentage of coverage with bacterial biofilm was measured with Carnoy software. Results. Bacterial biofilm was present in a higher percentage in patients with CRS vs. CRSNP. By comparing the level of olfactory function, significant improvement was found after FESS intervention in both study groups. Postoperatively, Lund-Kennedy scores decrease significantly for the whole group (Z = -9.66 at p &lt; 0.001, d Cohen = 4.40), indicating the major role of surgery in the treatment of CRS. The decrease in Lund-Kennedy score values is also significant for each group. In the case of subjects diagnosed with CRS, the mean values decrease from 6.57 (preoperative) to 0.90 (postoperative), respectively Z = -6.779 to p &lt; 0.001. In the case of subjects diagnosed with CRSNP, the mean values decrease from 9.03 (preoperative) to 1.44 (postoperative), Z = -6.927 at p &lt; 0.001. Out of the total number of patients included in the study, 59 patients tested positive with the Prick test for dust and mites and more than half of the patients with positive allergy test were from the lot diagnosed with CRSNP. Conclusions. FESS plays an important role in the improvement of olfactory function in patients with CRS. Bacterial biofilm was present in both study groups but in higher percentage in the CRS group and was found in lower percentage in the group with positive allergy tests. The CRSNP group presented a higher positive result regarding the allergy Prick test and a lower percentage of coverage with bacterial biofilm of the nasal mucosa. In conclusion, chronic rhinosinusitis with or without nasal polyps that is refractary to antibiotic therapy should be directed to the ENT department in order to receive surgical therapy in order to improve olfactory function.

Six-month smell and taste recovery rates in coronavirus disease 2019 patients: a prospective psychophysical study.

The long-term recovery rate for coronavirus disease 2019 related chemosensory disturbances has not yet been clarified. Olfactory and gustatory functions were assessed with psychophysical tests in patients in the first seven days from coronavirus disease 2019 onset and one, two, three and six months after the first evaluation. A total of 300 patients completed the study. The improvement in olfactory function was significant at the two-month follow up. At the end of the observation period, 27 per cent of the patients still experienced a persistent olfactory disturbance, including anosmia in 5 per cent of cases. As for taste, the improvement in the psychophysical scores was significant only between the baseline and the 30-day control. At the 6-month evaluation, 10 per cent of the patients presented with a persistent gustatory disturbance with an incidence of complete ageusia of 1 per cent. Six months after the onset of coronavirus disease 2019, about 6 per cent of patients still had a severe persistent olfactory or gustatory disturbance.

Persisting olfactory dysfunction improves in patients 6 months after COVID-19 disease

Background Smell disorders persist in about half of the patients with other symptoms of COVID-19 disease, but the exact duration of the symptoms is yet unknown. Especially, only a few studies used validated olfactory tests for this. Aims/Objectives The aim of this study was to investigate how many patients with olfactory function impairment, which was detected in a validated olfactory test 3 months after COVID-19 disease, showed improvement in olfactory function after 6 months. Methods About 26 patients with a PCR-confirmed, former COVID-19 disease, with an impaired olfactory function after three months, were included in the study. The olfactory function was evaluated with the sniffing sticks test, the taste function with taste sprays. Results Smelling function improved in all but one patient (96%). All measured subitems, i.e. olfactory threshold, identification and discrimination of odours significantly improved. In the whole mouth taste test all patients showed normal taste function. Conclusions and significance 6 months after COVID-19 disease, olfactory function improves in just about all patients. Long-term measurements must investigate whether complete regeneration of the olfactory function will occur in all patients.

Sustained Chemosensory Dysfunction during the COVID-19 Pandemic

Introduction: Chemosensory dysfunction (CD) has proven valuable in prediction of COVID-19, as it is a frequent and specific symptom of the disease. The aim of this study was to investigate the duration of CD in patients with sudden subjective olfactory and/or gustatory loss during the SARS-CoV-2 pandemic. The secondary aim was to identify possible prognostic factors for the duration of CD. Methods: An online baseline questionnaire was designed to assess subjective CD. Three rounds of follow-up questionnaires were sent out to any participants with persistent CD in 6-week intervals, prospectively assessing subjective chemosensory function and extending the follow-up time of this cohort significantly. Results: In total, 467 participants completed the baseline questionnaire. The most significant improvement and recovery of chemosensory function was observed within the first month after the initial loss. Rates became stagnant after about 2 months, and only little improvement and recovery was seen after 2–4 months. After a mean follow-up of 95.9 days (olfactory dysfunction) and 94.0 days (gustatory dysfunction), 86.7% of participants reported gustatory improvement and 82.6% reported olfactory improvement, while 55.0% reported full gustatory recovery and 43.8% reported full olfactory recovery. Female gender was associated with better improvement of gustatory function. High subjective severity of chemosensory loss was associated with lower rates of olfactory and gustatory recovery as well as improvement of olfactory function. Young age was not associated with a better prognosis. Discussion/Conclusion: Rates of improvement and recovery of chemosensory function decreased after 2–4 months after initial chemosensory loss, possibly indicating that prolonged and perhaps permanent chemosensory loss may be a complication of SARS-CoV-2 infections. High subjective severity of CD may worsen the prognosis for improvement and recovery of chemosensory function.

Assessment of Olfaction Following Endoscopic Sinus Surgery.

To assess the olfactory outcomes following Endoscopic Sinus Surgery (ESS) in patients diagnosed with Chronic Rhinosinusitis (CRS) and Sinonasal polyposis (SNP). To assess and compare the pre-operative and post-operative olfactory scores of patients undergoing ESS/ ESS + polypectomy/ESS + Septoplasty by subjective and objective methods. This is a prospective, cohort study which included a total of 60 patients. Subjective assessment was done using a Questionnaire. Preoperative olfactory assessment was performed with Sniffing Sticks. Olfactory assessment was done at 1st,3rd, 6th and 12th week following surgery. The preoperative and postoperative scores were statistically analysed and compared. In patients who underwent ESS, there was a significant reduction in olfactory scores in the immediate few weeks after surgery which improved over time by the end of 3months. In patients who underwent ESS with polypectomy, there was a significant improvement in olfactory scores from the third week following surgery which was sustained over 3rd month follow-up. In patients who underwent ESS with Septoplasy, there was a significant decrease in olfactory scores during the initial few weeks with a marginal improvement during 3months follow-up. At the end of 12weeks post ESS, no patient was found to be anosmic. Patients with pre-existing hyposmia did not show statistically significant change post surgery.However patients with anosmia showed statistically significant improvement in olfactory function, but did not become normosmic at 12th post-operative week. Majority of normosmics did not have alteration in their olfactory perception at 12th post-operative week.

Efficacy of corticosteroid therapy in the treatment of long- lasting olfactory disorders in COVID-19 patients.

The growing number of COVID-19 patients with long-lasting olfactory disorders makes it necessary to identify ef- fective treatments that enhance the spontaneous recovery of olfactory function. Multicentre randomised case-control study that involved 18 patients with COVID-19 related anosmia or severe hyposmia for more than 30 days. Nine patients were prescribed systemic prednisone and nasal irrigation with betamethasone, ambroxol and rinazine for 15 days. The other 9, untreated, patients were used as controls. The olfactory function was evaluated with CCCRC test at 20 and 40 days from the first evaluation. In the control group, a median olfactory score of 20 (IQR 30) was detected at baseline. At the 20-day control there was no significant improvement in olfactory function. The improvement in olfactory performance became significant at the 40-day follow-up compared to baseline scores [60 (IQR 60) versus 20 (IQR 30)]. In the treatment group, patients had a mean olfactory score of 10 (IQR 15) at initial control. At the 20-day control, a significant im-provement in the olfactory scores, compared to the baseline, was detected [70 (IQR 40) versus 10 (IQR 15)]. Olfactory function further improved at 40 days [median score 90 (IQR 50)]. Patients in the treatment group reported significantly higher improvements of the olfactory scores than the controls at both the 20-day [40 (IQR 45) versus 10 (IQR 15)] and 40-day [60 (IQR 40) versus 30 (IQR 25)] evaluations. Based on the results of this study, the mix of drugs including steroids could represent a useful specific therapy to reduce the prevalence of this long-term morbidity.

Olfactory Dysfunction in Traumatic Brain Injury: the Role of Neurogenesis.

Olfactory functioning disturbances are common following traumatic brain injury (TBI) having a significant impact on quality of life. A spontaneous recovery of the olfactory function over time may occur in TBI patients. Although there is no standard treatment for patients with posttraumatic olfactory loss, olfactory training (OT) has shown some promise beneficial effects. However, the mechanisms underlying spontaneous recovery and olfactory improvement induced by OT are not completely known. The spontaneous recovery of the olfactory function and the improvement of olfactory function after OT have recently been associated with an increase in subventricular (SVZ) neurogenesis and an increase in olfactory bulb (OB) glomerular dopaminergic (DAergic) interneurons. In addition, after OT, an increase in electrophysiological responses at the olfactory epithelium (OE) level has been reported, indicating that recovery of olfactory function not only affects olfactory processing at the central level, but also at peripheral level. However, the role of OE stem cells in the spontaneous recovery and in the improvement of olfactory function after OT in TBI is still unknown. In this review, we describe the physiology of the olfactory system, and the olfactory dysfunction after TBI. We highlight the possible role for the SVZ neurogenesis and DAergic OB interneurons in the recovery of the olfactory function. In addition, we point out the relevance of the OE neurogenesis process as a future target for the research in the pathophysiological mechanisms involved in the olfactory dysfunction in TBI. The potential of basal stem cells as a promising candidate for replacement therapies is also described.

Prognostic Factors for Olfactory Dysfunction in Adult Mild Head Trauma

Although posttraumatic olfactory disturbances are frequent, they have a poor prognosis. Our study aimed to investigate the impact of clinical factors on the progress of these olfactory disturbances. Among patients admitted with evidence of head trauma, only suspected cases of posttraumatic olfactory disturbances were included. Patients were examined by the Sniffin'Sticks test, early posttraumatic and then later after recovery. Such factors as age, sex, olfactory bulb status, and observation period were enrolled in logistic regression analysis, because they are considered to have a possible influence on olfactory function improvements. Amelioration of olfaction was expressed as an alteration in olfactory function to a better level. A total of 70 patients were involved, with a mean age of 38 years. The mean duration of follow-up was 6 months. Twelve patients (17.1%) had olfactory function improvements. In univariate and multivariate analyses, no clinical factors had an impact on olfactory recovery (all P > 0.05) except olfactory bulb integrity, which appears to influence improvement in olfactory function (P= 0.0327 and 0.0293). Olfactory bulb integrity, probably the sole prognostic factor for posttraumatic olfactory recovery, where frank damage to such a structure carries a prognosis of poor posttraumatic olfactory function.