Improvement In Olfactory Function Research Articles

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.

The Impact of High-Flow Nasal Cannula on Olfactory Function.

Oxygen therapy provided via high-flow nasal cannula (HFNC) improves gas exchange lung compliance and results in increased lung expiratory volumes. Previous data indicate that hyperbaric and humid states improve the olfactory thresholds compared to hypobaric and dry conditions. This prospective, observational study aimed to determine the impact of oxygen delivery through HFNC on olfactory function in subjects admitted to the ICU for acute respiratory failure (ARF). 30 subjects who were admitted to the ICU for ARF underwent an olfactory sniff test before and after oxygen therapy with HFNC. Baseline olfactory function of subjects with ARF was also compared against 30 healthy controls. Odor threshold (OT), odor discrimination (OD), odor identification (OI) and global olfactory score (TDI) were recorded for all subjects. The OT, OD, OI, and TDI scores were significantly higher in the control group compared to the baseline scores of the subjects with ARF (P < .001 for all comparisons). In subjects with ARF, administration of oxygen with HFNC led to significant improvements in OT (P = .02), OD (P = .001), OI (P = .02), and TDI (25.5 ± 3.8 vs 27.1 ± 3.5, P < .001) scores. Our results indicate that subjects with ARF had relative olfactory dysfunction compared to healthy controls. These results also suggest that implementation of HFNC to relieve hypoxemia in subjects presenting with ARF can lead to a significant improvement in olfactory function.

Effect of endoscopic sinus surgery on olfactory function in patients with chronic rhinosinusitis with nasal polyps

Objective:To evaluate the effect of surgery on olfactory function in patients with chronic rhinosinusitis with nasal polyps（CRSwNP） by subjective and objective olfactory tests. Method:This was a retrospective study. Forty patients with CRSwNP who underwent endoscopic sinus surgery（ESS） from 2015 to 2017 in Beijing Anzhen Hospital were enrolled. Postoperative time was 6-46 months. The patients were followed up in October 2018 and examined using Sniffin' sticks olfactory test and olfactory event-related potentials （oERP）. The polyps collected during surgery were performed to eosinophil count and percentage calculation. They were divided into eosinophilic CRSwNP（ECRS） and non-eosinophilic CRSwNP（NECRS）. The subjective and objective olfactory functions between the two groups were compared before and after surgery respectively and the paired T test was performed between the postoperative and the preoperative Sniffin' sticks olfactory test. Covariance analysis was used to adjust the effect of different postoperative time on postoperative olfactory recovery. Result:There were 21（52.5%） ECRS and 19（47.5%） NECRS patients of the 40 patients with nasal polyps. There was statistical difference in the posterior ethmoid score and the posterior olfactory cleft score of CT. According to the criterion of total TDI increased more than 5.5, olfactory function in 21（52.5%） patients had improved. In addition, there was a significant improvement in olfactory function in ECRS group either in unilateral T/TDI or bilateral T/D/TDI, but only unilateral T/TDI increased in NECRS group. There was no significant difference in Sniffin' sticks olfactory test between the two groups, but there was a statistically significant difference in the latency of oERP after surgery. Conclusion:ESS could improve olfactory function in patients with CRSwNP by more than 50%. Bilateral olfactory improvement in ECRS was better than that in NECRS, but olfactory function in postoperative ECRS was still lower than that in NECRS. oERP can more objectively and accurately reflect the severity of olfactory disorders associated with eosinophilic inflammation.

Structural Plasticity of the Primary and Secondary Olfactory cortices: Increased Gray Matter Volume Following Surgical Treatment for Chronic Rhinosinusitis

Functional plasticity of the adult brain is well established. Recently, the structural counterpart to such plasticity has been suggested by neuroimaging studies showing experience-dependent differences in gray matter (GM) volumes. Within the primary and secondary olfactory cortices, reduced GM volumes have been demonstrated in patients with olfactory loss. However, these cross-sectional studies do not provide causal evidence for GM volume change, and thereby structural plasticity. Disorders of the peripheral olfactory system, such as chronic rhinosinusitis (CRS), provide an ideal model to study GM structural plasticity, given that patients may experience long periods of olfactory impairment, followed by near complete recovery with treatment. We therefore performed a prospective longitudinal study in patients undergoing surgical treatment for CRS. We used voxel-based morphometry (VBM) to investigate GM volume change in 12 patients (M:F = 7:5; 47.2 ± 14.9 years), 3 months post-op. There was a significant improvement in olfactory function according to birhinal psychophysical testing. We performed a voxel-wise region of interest analysis, with significance corrected for number of regions (p < 0.0036corr). We found significantly increased post-operative GM volumes within the primary (left piriform cortex, right amygdala) and secondary (right orbitofrontal cortex, caudate nucleus, hippocampal–parahippocampal complex and bilateral temporal poles) olfactory networks, and decreased GM volumes within the secondary network only (left caudate nucleus and temporal pole, bilateral hippocampal–parahippocampal complex). As a control measure, we assessed GM change within V1, S1 and A1, where there were no suprathreshold voxels. To our knowledge, this is the first study to demonstrate GM structural plasticity within the primary and secondary olfactory cortices, following restoration of olfaction.

An Enriched Environment Ameliorates Oxidative Stress and Olfactory Dysfunction in Parkinson’s Disease with α-Synucleinopathy

Parkinson’s disease (PD) features nonmotor symptoms such as olfactory dysfunction referred to as hyposmia, an initial sign of disease progression. Metabolic dysfunction can contribute to neurodegenerative diseases, and various xenobiotics and endogenous compounds are also involved in the pathogenesis of PD. Although aerobic exercise was found to induce preservation or improvement in olfactory function in PD patients in a recent study, the exact underlying mechanism for this effect is not clear. We aimed to investigate the influence of an enriched environment (EE) on olfactory dysfunction especially via metabolic pathways related to detoxification enzymes. Eight-month-old transgenic (Tg) PD mice that overexpress human A53T α-synuclein (α-syn) were randomly allocated to an EE or standard conditions for 2 mo. The buried food test showed that EE group had significantly improved olfactory function compared to the control group. Reverse transcription polymerase chain reaction (PCR) and real-time quantitative PCR showed that expression of the detoxification enzymes––cytochrome P450 family 1 subfamily A member 2, paraoxonase 1, alcohol dehydrogenase 1, UDP glucuronosyltransferase family 2 member A1 complex locus, aldehyde oxidase homolog 2, and aldehyde glutathione peroxidase 6––was significantly increased in the olfactory bulb (OB) of the PD control group, but these enzymes were normalized in the EE group. Immunohistochemical staining of the OB showed that oxidative stress and nitrated α-syn were significantly increased in the control group but decreased in the EE group. In conclusion, we suggest that exposure to an EE decreases both oxidative stress and nitrated α-syn, resulting in normalized detoxification enzymes and amelioration of olfactory dysfunction.

Improvement of Olfactory Function With High Frequency Non-invasive Auricular Electrostimulation in Healthy Humans.

In past literature on animal models, invasive vagal nerve stimulation using high frequencies has shown to be effective at modulating the activity of the olfactory bulb (OB). Recent advances in invasive vagal nerve stimulation in humans, despite previous findings in animal models, used low frequency stimulation and found no effect on the olfactory functioning. The present article aimed to test potential effects of non-invasive, high and low frequency vagal nerve stimulation in humans, with supplementary exploration of the orbitofrontal cortex using near-infrared spectroscopy (NIRS). Healthy, male adult participants (n = 18) performed two olfactory tests [odor threshold test (OTT) and supra-threshold test (STT)] before and after receiving high-, low frequency vagal nerve stimulation and placebo (no stimulation). Participant's olfactory functioning was monitored using NIRS, and assessed with two behavioral olfactory tests. NIRS data of separate stimulation parameters were statistically analyzed using repeated-measures ANOVA across different stages. Data from olfactory tests were analyzed using paired parametric and non-parametric statistical tests. Only high frequency, non-invasive vagal nerve stimulation was able to positively modulate the performance of the healthy participants in the STT (p = 0.021, Wilcoxon sign-ranked test), with significant differences in NIRS (p = 0.014, post-hoc with Bonferroni correction) recordings of the right hemispheric, orbitofrontal cortex. The results from the current article implore further exploration of the neurocircuitry involved under vagal nerve stimulation and the effects of non-invasive, high frequency, vagal nerve stimulation toward olfactory dysfunction which showcase in Parkinson's and Alzheimer's Diseases. Despite the sufficient effect size (moderate effect, correlation coefficient (r): 0.39 for the STT) of the current study, future research should replicate the current findings with a larger cohort.

Differences in clinical features of post-traumatic olfactory dysfunction and non-post-traumatic olfactory dysfunction: a follow-up study

Objective:To analyze the clinical features and recovery rate of post-traumatic olfactory dysfunction (PTOD) in Chinese adults in a case control follow-up study. Method:The clinical data of 202 patients who were diagnosed with olfactory dysfunction between January 2015 and December 2016 and followed up for 14 to 473 days were analyzed in this retrospective study. The patients were divided into those with PTODs (PTOD group) and those without PTODs (non-PTOD group). The two groups were compared with regard to age (years), sex, olfactory function (Sniffin' sticks), gustatory function (triple drop method), chemosensory evoked potentials, and magnetic resonance imaging (MRI) characteristics of olfactory pathways. The recovery rate of PTOD was evaluated by Sniffin' sticks and triple drop method. Result:Patients in the PTOD group (40±11 years) were significantly younger than those in the non-PTOD group (47±15 years), whereas the number of men and women was similar in both groups. The mean TDI score (Sniffin' sticks) was significantly different between the PTOD (12±5) and non-PTOD (19±8) groups (P<0.05). The mean oERP P2 latency was significantly shorter for the non-PTOD group (418±64 ms) than for the PTOD group (483±82 ms, P<0.05). There were no significant differences in the mean oERP N1 latency, N1 amplitude, P2 amplitude, mean tERP P2 latency and MRI between the two groups. After the follow-up period, 8.9% (5/56) and 5.4% (3/56) patients in the PTOD group exhibited an improvement in olfactory function and gustatory function, respectively. Conclusion:PTOD should be considered a type of disability that can lead to serious accidents, and an adequate understanding of its clinical features and etiologies is critical for appropriate diagnosis and treatment and for improving the prognosis of treatment. The rate of recovery of olfactory function is higher than that of gustatory function in patients with PTOD; further investigations are required in this regard.

The role of Functional Endoscopic Sinus Surgery (FESS) to improve olfactory function in chronic rhinosinusitis patients without polyps

Background: Olfactory dysfunction is one of the chronic rhinosinusitis symptoms. A large number of patients with chronic rhinosinusitis without polyps whose treated by Functional Endoscopic Sinus Surgery (FESS) need to be investigated using Sniffin ' sticks test before and after surgery. Objective: The aim of this study is to investigate the role of olfactory function improvement after FESS in patients with chronic rhinosinusitis without polyps. Methods: This study is an experimental study using one group pre-post test design. The measurement of the threshold, discrimination, identification, and TDI scores were assessed by Sniffin’ stick test in 3 periods (before FESS, 2 weeks and 4 weeks after FESS intervention). Results: The mean value of the TDI score before FESS performed was 19.43 ± 7.32 (hyposmia), 2 weeks after the operation was 26.9 ± 5.78 (hyposmia), and 4 weeks after the operation was 33.25 ± 3.86 (normosmia).There is a significant mean difference in thresholds, discrimination, identification, and olfactory function (TDI) scores in patients with chronic rhinosinusitis without polyps before FESS, 2 weeks after the procedure, and 4 weeks after FESS. Conclusion:There was a significant improvement in olfactory function after FESS performed in patients with chronic rhinosinusitis without polyps.

Improvement of olfactory function after sinus surgery correlates with white matter properties measured by diffusion tensor imaging

Impaired olfaction is associated with a volume decrease in the olfactory bulb as well as in the gray matter of cortical olfactory areas. On the other hand, restitution of an impaired olfaction results in a regain of volume in these regions. Studies investigating similar changes in the cerebral white matter are virtually not existent. The aim of this prospective study therefore was to investigate cerebral white matter using magnetic resonance diffusion tensor imaging (DTI). 31 patients (54±13years) with olfactory impairment (chronic rhinosinusitis) and planned functional endoscopic sinus surgery (FESS) were included. Magnetic resonance imaging (MRI) data sets were acquired pre-operatively and 3months after surgery. Pre- and postoperative olfactory testing was performed to assess the olfactory threshold, discrimination, and identification (TDI) score. A significant postoperative TDI improvement by 9.06±8.81 points was observed. Two groups were subsequently formed – one with relevant postoperative olfactory gain (ΔTDI≥10 points, 12 patients) and one without gain (ΔTDI<10 points, 19 patients). DTI parameter showed a significant correlation with the TDI score in the left anterior cingulate cortex and the right amygdala. In the group with relevant olfactory improvement higher values of fractional anisotropy and apparent diffusion coefficient were found in the right parahippocampal area and in the white matter below the left inferior temporal sulcus. Tract-specific diffusion property analysis revealed significant group differences in the cingulate cortex in spatial relationship to the perisplenial cortex. Overall, this prospective study indicates structural changes in white matter after postoperative restoration of olfaction.

Smoking and olfactory dysfunction: A systematic literature review and meta-analysis.

A systematic review and meta-analysis of the literature was undertaken, examining the association between tobacco smoking and olfactory function in humans, utilizing PubMed and Web of Science (1970-2015) as data sources. Systematic literature review and meta-analysis. This database review of studies of smoking and olfaction, with a focus on identifying high-quality studies (based on modified versions of the Newcastle-Ottawa Scale), used validated olfactory tests among the generally healthy population. We identified 11 studies meeting inclusion criteria. Of 10 cross-sectional studies, two were excluded from meta-analysis because the cohorts they studied were included in another article in the review. In meta-analysis, current smokers had substantially higher odds of olfactory dysfunction compared to never smokers (odds ratio [OR] = 1.59, 95% confidence interval [CI] = 1.37-1.85). In contrast, former smokers were found to have no difference in risk of impaired olfaction compared to never smokers (OR = 1.05, 95% CI = 0.91-1.21). The single longitudinal study reviewed found a trend toward increased risk of olfactory decline over time in ever smokers; this trend was stronger in current as compared to former smokers. Current smoking, but not former smoking, is associated with significantly increased risk of olfactory dysfunction, suggesting that the effects of smoking on olfaction may be reversible. Future studies that prospectively evaluate the impact of smoking cessation on improvement in olfactory function are warranted. N/A. Laryngoscope, 127:1753-1761, 2017.

Clinical analysis of chronic rhinosinusitis in the different age group patients

Objective:To investigate the clinical materials of chronic rhinosinusitis (CRS) in the different age group patients and explore its clinical characteristics and prognosis.Method:A retrospective analysis was carried out in 395 CRS patients with surgical treatment in our hospital in the past three years. They were divided into the young group (18 to 39 years old ), the middle-aged group (40 to 59 years old ), and the old group (over 60 years old). The clinical symptoms, accompanying diseases and prognosis in CRS patients were analyzed.Result:Among the presenting symptoms,facial pain and rhinorrhea were most common in the young group (P< 0.05), while dysosmia was most common in the old group (P< 0.05). Allergy was more prevalent in the young group and the middle-aged group than the old group (P< 0.05). CRS without polyposis was the most common diagnosis in the young group and CRS with polyposis was the more common diagnosis in the middle-aged group and the old group (P< 0.05). Patients in the young group got higher rate of improvement in olfactory function while patients in the old group got higher rate of improvement in rhinorrhea following FESS (P< 0.05).Conclusion:CRS in different age groups had different clinical features and prognosis. We can improve the personalized treatment program to this disease through the classification and grading treatment.

Effects of triamcinolone-impregnated nasal dressing on subjective and objective outcomes following endoscopic sinus surgery.

The aim of this study was to compare the effects of triamcinolone (TA)- and saline-soaked biodegradable nasal dressing on subjective symptoms, wound healing and improvement of olfactory dysfunction in patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) after undergoing endoscopic sinus surgery (ESS). The study was a prospective, randomized, double-blinded, placebo-controlled study. A total of 80 patients undergoing bilateral ESS for CRSwNP were enrolled and randomly assigned to two groups. Nasal dressing was impregnated with normal saline in the control group, while patients received triamcinolone-impregnated dressing in the TA group. Sino-Nasal Outcome Test 20 (SNOT-20) and Korean Version of the Sniffin' Stick (KVSS) II test were used to assess the patients' condition preoperatively and at postoperative 1 and 3months. Lund-Kennedy (L-K) and perioperative sinus endoscopy (POSE) scores were assessed on postoperative months 1, 2, and 3. There were significant differences between the control group and the TA group in terms of postoperative L-K scores and POSE scores at 1 and 2months. The postoperative endoscopic scores were significantly decreased in the TA group compared to the control at 1month. Olfactory functions were significantly improved at postoperative 3months (p=0.0099) compared to the preoperative score in the TA group. Significant improvement in the olfactory functions among anosmic and hyposmic patients at postoperative 1month (p=0.0475) and 3months (p=0.0019) compared to their preoperative olfactory function score was observed only in the TA group. TA-impregnated dressing had a significant advantage over saline-soaked dressing with regard to postoperative wound healing and improvement of olfactory function.

Efficacy of olfactory training in patients with olfactory loss: a systematic review and meta-analysis.

Olfactory loss is a challenging clinical problem with few proven therapeutic options. Early experimental results with olfactory training suggest that this novel therapy may be an effective intervention for olfactory dysfunction of multiple etiologies. The aim of this study was to systematically review currently available studies that assess the efficacy and outcomes of olfactory training in patients with olfactory loss. A comprehensive systematic literature review was performed with the assistance of a reference librarian using the PubMed, PsycInfo, Google Scholar, EMBASE, and Proquest databases. Eligible studies were extracted based on defined inclusion criteria and the effect of olfactory training on objective olfactory function was evaluated qualitatively and by meta-analysis. A total of 10 studies with 639 patients were identified and systematically reviewed. Sufficient data for meta-analysis was available for 3 studies. Patients receiving olfactory training experienced a statistically significant improvement in the Threshold, Discrimination, Identification (TDI) score compared to control patients (mean difference [MD] 3.77; 95% confidence interval [CI], 2.28 to 5.26). Improvement in olfactory function was observed in discrimination (MD 1.92; 95% CI, 1.13 to 2.71) and identification (MD 1.61; 95% CI, 0.55 to 2.68), but not in olfactory thresholds (MD -0.01; 95% CI, -0.42 to 0.39). Olfactory training is a promising modality for the treatment of olfactory dysfunction. Results of this systematic review and meta-analysis suggest that it may be an effective treatment for olfactory dysfunction due to multiple etiologies. Additional high-quality studies are needed to define indications, outcomes, and duration of therapy for this novel therapy.

Olfaction improvement after nasal septal perforation repair with the "cross-stealing" technique.

The surgical treatment of nasal septal perforation is known to improve nasal respiratory airflow and, thereby, should be beneficial to the patient's olfactory abilities. However, there are only limited data on the effect of nasal septal perforation repair (NSPR) on olfaction, and most studies reported contradictory results. The aim of this prospective study was to investigate the change in the olfactory abilities of 42 patients with a primary concern of nasal septal perforation. NSPR was performed with the "cross-stealing" technique. The inferior-based mucoperichondrial flap in one side and the superior-based mucoperichondrial flap from the other side of the nasal septum were passed to the opposite sides through the perforation. Surgery was completed by placing an interpositional graft between the flaps before suturing. The interpositional grafts were residual cartilage. The olfactory performance of the patients before and at 1, 3, and 6 months after the closure of the nasal septal perforation was measured by using an olfaction test kit. The success rate with complete closure of nasal septal perforation with the "cross-stealing" technique was 92.8%. Analysis of the data indicated statistically significant improvement in olfactory function scored as odor threshold (T), odor discrimination (D), odor identification (I) and TDI at 1, 3, and 6 months after NSPR (p < 0.001 for all). The mean TDI score evaluated 6 months after NSPR was improved by 64%. Analyses of variance indicated statistically significant improvement in olfactory scores within time factors were calculated as preoperative versus 1, 3, and 6 months; 1 versus 3 and 6 months; and 3 versus 6 months (p < 0.001 for all). Analysis of the present data indicates a beneficial effect of NSPR on olfactory abilities of patients with perforation. Our data on the short- and long-term olfactory abilities of 42 patients with nasal septal perforation after NSPR when using an olfaction test kit indicated statistically significant improvement in olfactory function.

Efficacy of ESS in chronic rhinosinusitis with and without nasal polyposis: a Danish cohort study.

Endoscopic sinus surgery (ESS) for patients with severe chronic rhinosinusitis (CRS) has become a well-established treatment in cases where medical therapy fails. Even though CRS patients are divided into two subgroups, CRS with nasal polyposis (CRSwNP) and CRS without nasal polyposis (CRSsNP), most studies present only results for the total cohort. This prospective cohort study evaluated the efficacy of ESS on both quality of life and olfactory function measures, in a cohort of Danish CRS patients diagnosed according to the EPOS criteria, with results analysed separately for the CRSwNP and CRSsNP subgroups. All 97 CRS patients who underwent ESS over an 18-month trial period were evaluated preoperative by SNOT-22 score, Sniffin' Sticks score, modified Lund-Kennedy endoscopic score and Lund-Mackay CT score. Patient outcomes were reevaluated at clinical follow-up 1 and 6 months postoperative. ESS efficiently and immediately improved quality of life for both CRSwNP and CRSsNP patients, with over 50 % reduction in SNOT-22 score 1 month after surgery, which sustained 6 months postoperative. Olfactory function measured by Sniffin' Sticks score showed overall improvement in both groups. ESS efficiently improved quality of life in both CRSwNP and CRSsNP patients, and surgery lead to an overall improvement in olfactory function. However, a minor proportion of patients experienced deterioration in olfactory function after ESS.