INTRODUCTION: Odour recognition is influenced by culture. Odour identification tests need to be adapted to a population to accurately assess olfactory function. This study's objectives were to validate the Singapore version of the Sniffin' Sticks (SS-Sg) and a locally-developed odour recognition test (Scentsor) for Singapore. METHOD: This prospective study was performed in 3 otolaryngology outpatient clinics in 3 phases (1 May to 15 November 2024). Phase 1 was a survey evaluation of 93 odour descriptors to identify familiar odour descriptors to be used in the tests (n=414); Phase 2 evaluated and finalised SS-Sg and Scentsor to ensure test odours were recognised by ≥75% of healthy controls (n=130); and Phase 3 validated both tests on healthy controls (n=473) to obtain normative data, to determine test-retest reliability (n=50), and to assess the ability to distinguish patients with olfactory loss (n=67). RESULTS: In Phase 1, the unmodified SS blue and purple sets had 15/32 (46.9%) unfamiliar test odours and 25 unfamiliar distractors combined. In Phase 2, after modification, all odours in SS-Sg and Scentsor were correctly identified by ≥75% of controls. In Phase 3, normative data (age 21-83 years) was obtained. Both tests had good test-retest reliability (Pearson's correlation coefficient of 0.88 with<0.001 for SS-Sg; and at 0.90 with<0.001 for Scentsor). Both tests differentiated among normosmia, hyposmia and anosmia (SS-Sg scores: 12.6 [±2.4] versus [vs] 9.8 (±3.2) vs 6.0 [±2.3] respectively,<0.001; Scentsor scores: 14.3 [±1.8] vs 11.3 [±2.8] vs 5.8 [±3.4] respectively,<0.001). CONCLUSION SS-Sg and Scentsor have been validated to assess olfaction in Singapore.
Humans ; Singapore ; Male ; Female ; Odorants/analysis* ; Middle Aged ; Prospective Studies ; Olfaction Disorders/diagnosis* ; Adult ; Reproducibility of Results ; Aged ; Smell/physiology* ; Young Adult

Objective:To explore the influencing factors related to olfactory dysfunction secondary to different types of chronic rhinosinusitis（CRS）. Methods:A retrospective analysis was conducted on 185 CRS patients treated at the Department of Otolaryngology-Head and Neck Surgery of Shanxi Provincial People's Hospital from July 2023 to July 2024. Based on the presence or absence of nasal polyps, CRS was divided into two groups: chronic rhinosinusitis with nasal polyps（CRSwNP） and chronic rhinosinusitis without nasal polyps（CRSsNP）. Further, based on whether olfactory dysfunction was present, the CRSwNP and CRSsNP groups were divided into subgroups with olfactory dysfunction and normal olfaction. General data, laboratory tests, and modified sinus CT scores were compared between the subgroups. Logistic regression analysis was conducted to identify independent influencing factors based on the results of univariate analysis combined with clinical significance, and two nomogram models were established. The area under the curve of the receiver operating characteristic（ROC） curve, calibration curves, and decision curve analysis were used to assess the diagnostic performance, calibration, and clinical utility of the predictive model. Results:The proportion of blood eosinophils, blood urea nitrogen, and total modified CT scores of the bilateral olfactory region were identified as independent influencing factors in the CRSwNP group; the proportion of blood monocytes and modified CT scores of the bilateral posterior region were independent influencing factors in the CRSsNP group. The nomogram prediction model showed good diagnostic performance, calibration, and clinical utility in both the CRSwNP and CRSsNP groups. Conclusion:Olfactory dysfunction in CRSwNP patients is closely related to the proportion of blood eosinophils, blood urea nitrogen, and total modified CT scores of the bilateral olfactory region, while olfactory dysfunction in CRSsNP patients is closely related to the proportion of blood monocytes and modified CT scores of the bilateral posterior region. Moreover, the predictive model established in this study demonstrates good clinical performance and can be used for early identification and risk prediction of olfactory dysfunction secondary to CRS.
Humans ; Sinusitis/complications* ; Chronic Disease ; Retrospective Studies ; Olfaction Disorders/etiology* ; Nasal Polyps/complications* ; Rhinitis/complications* ; Female ; Male ; Logistic Models ; Middle Aged ; Smell ; Adult ; ROC Curve ; Nomograms ; Eosinophils ; Tomography, X-Ray Computed

Total laryngectomy is a crucial surgical intervention for patients with advanced malignant tumors of the larynx and nasopharynx. Despite its effectiveness, this procedure permanently severs the connection between the nasal cavity and the lower respiratory tract, leading to the cessation of nasal airflow. This disruption significantly impairs the patient's sense of smell and adversely affects their quality of life. Although olfactory loss is common in these patients, the assessment and rehabilitation of their olfactory function are often overlooked. This article reviews relevant literature on evaluating olfactory function and rehabilitation methods following total laryngectomy, with the aim of providing a theoretical foundation to enhance olfactory rehabilitation and overall quality of life for these patients.
Humans ; Laryngectomy/rehabilitation* ; Quality of Life ; Smell ; Laryngeal Neoplasms/surgery* ; Olfaction Disorders/etiology*

Objective: To determine the relationship between olfactory function threshold and quality of life (QOL) among adult Filipinos with perceived olfactory dysfunction (OD). Methods: Design:Cross - Sectional Study. Setting:Tertiary Government Training Hospital. Participants: 98 adults who had self-perceived olfactory dysfunction described as “poor” or “no sense” of smell Results: We analyzed data from 98 participants, with a mean age of 35.91 + 12.58 years old, composed of 46 men (47%) and 52 women (53%), with 82 normosmic, six hyposmic and ten anosmic as categorized by their BTT scores. Twenty-seven percent (27%) identified themselves as having poor QOL based on Fil 17 QODNS. Differences were exhibited between sexes’ BTT scores - [t(96) = -2.32; p = .022; females, M: 9.25; SD: 2.33 vs. males, M: 7.76; SD : 3.91], civil status - Fil17QODNS scores [t(96)= 3.05, p < .003; married M: 11.72, SD: 13.74 vs. single, M: 4.71; SD: 8.66), and the presence of ENT symptoms BTT [t(96) = -7.15; p < .0001; symptomatic, M: 5.62; SD: 4.54, vs. asymptomatic, M: 9.78; SD: 1.14] and Fil 17 QODNS scores [t(96)= 3.94; P < .00001; symptomatic, M: 14.86; SD: 13.97] vs. asymptomatic, M: 5.217; SD: 9.60]. Significant risk factors were the presence of ENT symptoms [OR= 0.15; 95% CI: 0.02-0.97; P = .046] for poor smell threshold, and comorbidities [OR= 3.36; 95% CI: 1.04-10.85; P = .043] for poor QOL. A negative correlation was observed between Fil-QOD-NS scores and BTT scores [r = -0.477, p < .001; rs = -0.292, p = .004], signifying that the presence of olfactory dysfunction has an inverse relationship with the quality of life. Conclusion Individuals with olfactory dysfunction in this study population had poor quality of life as determined by the translated Filipino 17-item QOD-NS which has an inverse relationship with their smell threshold as represented by the BTT results. Among the factors studied, significant differences were found between sexes, civil status and presence of ENT symptoms in the BTT and Fil 17 QODNS scores. However, only presence of comorbidities and ENT symptoms are significant risk factors for quality of life and smell threshold, respectively, in this population.
Smell ; Quality of Life

Olfactory bulb is a critical component in encoding and processing olfactory signals, characterized by its intricate neural projections and networks dedicated to this function. It has been found that descending neural projections from the olfactory cortex and other advanced brain regions can modulate the excitability of olfactory bulb output neurons in the olfactory bulb, either directly or indirectly, which can further influence olfactory discrimination, learning, and other abilities. In recent years, advancements in optogenetic technology have facilitated extensive application of neuron manipulation for studying neural circuits, thereby greatly accelerating research into olfactory mechanisms. This review summarizes the latest research progress on the regulatory effects of neural projections from the olfactory cortex, basal forebrain, raphe nucleus, and locus coeruleus on olfactory bulb function. Furthermore, the important role that photogenetic technology plays in olfactory mechanism research is evaluated. Finally, the existing problems and future development trends in current research are preliminarily proposed and explained. This review aims to provide new insights into the mechanisms underlying olfactory neural regulation as well as applications of optogenetic technology, which are crucial for advancing the research on olfactory mechanism and the application of optogenetic technology.
Olfactory Bulb/physiology* ; Optogenetics/methods* ; Animals ; Humans ; Olfactory Pathways/physiology* ; Olfactory Cortex/physiology* ; Smell/physiology*

Objective:To analyze the influencing factors and perform the prediction of olfactory disorders in patients with chronic rhinosinusitis（CRS） based on artificial intelligence. Methods:The data of 75 patients with CRS who underwent nasal endoscopic surgery from October 2021 to February 2023 in the Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively. There were 53 males and 22 females enrolled in the study, with a median age of 42.0 years old. The CRS intelligent microscope interpretation system was used to calculate the proportion of area glands and blood vessels occupy in the pathological sections of each patient, and the absolute value and proportion of eosinophils, lymphocytes, plasma cells and neutrophils. The patients were grouped according to the results of the Sniffin' Sticks smell test, and the clinical baseline data, differences in nasal mucosal histopathological characteristics, laboratory test indicators and sinus CT were compared between the groups. Determine the independent influencing factors of olfactory disorders and receiver operating characteristic curves（ROC） were used to evaluate the performance of the prediction model. Statistical analysis was performed using SPSS 25.0 software. Results:Among the 75 CRS patients, 25 cases（33.3%） had normal olfaction and 50 cases（66.7%） had olfactory disorders. Multivariate Logistic regression analysis showed that tissue eosinophils percentage（OR=1.032, 95%CI 1.002-1.064, P=0.036）, Questionnaire of olfactory disorders-Negative statement（QOD-NS）（OR=1.079, 95%CI 1.004-1.160, P=0.040） and Anterior olfactory cleft score（AOCS）（OR=2.672, 95%CI 1.480-4.827, P=0.001） were independent risk factors for olfactory disorders in CRS patients. Further research found that the area under the ROC curve（AUC） of the combined prediction model established by the tissue eosinophil percentage, QOD-NS and AOCS was 0.836（95%CI 0.748-0.924, P<0.001）, which is better than the above single factor prediction model in predicting olfactory disorders in CRS. Conclusion:Based on pathological artificial intelligence, tissue eosinophil percentage, QOD-NS and AOCS are independent risk factors for olfactory disorders in CRS patients, and the combination of the three factors has a good predictive effect on CRS olfactory disorders.
Male ; Female ; Humans ; Adult ; Retrospective Studies ; Artificial Intelligence ; Rhinosinusitis ; Rhinitis/complications* ; Nasal Polyps/complications* ; Sinusitis/complications* ; Olfaction Disorders/etiology* ; Smell ; Chronic Disease

Humans ; Olfaction Disorders/etiology* ; Smell

Objective: This cross-sectional investigation aimed to determine the incidence, clinical characteristics, prognosis, and related risk factors of olfactory and gustatory dysfunctions related to infection with the SARS-CoV-2 Omicron strain in mainland China. Methods: Data of patients with SARS-CoV-2 from December 28, 2022, to February 21, 2023, were collected through online and offline questionnaires from 45 tertiary hospitals and one center for disease control and prevention in mainland China. The questionnaire included demographic information, previous health history, smoking and alcohol drinking, SARS-CoV-2 vaccination, olfactory and gustatory function before and after infection, other symptoms after infection, as well as the duration and improvement of olfactory and gustatory dysfunction. The self-reported olfactory and gustatory functions of patients were evaluated using the Olfactory VAS scale and Gustatory VAS scale. Results: A total of 35 566 valid questionnaires were obtained, revealing a high incidence of olfactory and taste dysfunctions related to infection with the SARS-CoV-2 Omicron strain (67.75%). Females(χ2=367.013, P<0.001) and young people(χ2=120.210, P<0.001) were more likely to develop these dysfunctions. Gender(OR=1.564, 95%CI: 1.487-1.645), SARS-CoV-2 vaccination status (OR=1.334, 95%CI: 1.164-1.530), oral health status (OR=0.881, 95%CI: 0.839-0.926), smoking history (OR=1.152, 95%CI=1.080-1.229), and drinking history (OR=0.854, 95%CI: 0.785-0.928) were correlated with the occurrence of olfactory and taste dysfunctions related to SARS-CoV-2(above P<0.001). 44.62% (4 391/9 840) of the patients who had not recovered their sense of smell and taste also suffered from nasal congestion, runny nose, and 32.62% (3 210/9 840) suffered from dry mouth and sore throat. The improvement of olfactory and taste functions was correlated with the persistence of accompanying symptoms(χ2=10.873, P=0.001). The average score of olfactory and taste VAS scale was 8.41 and 8.51 respectively before SARS-CoV-2 infection, but decreased to3.69 and 4.29 respectively after SARS-CoV-2 infection, and recovered to 5.83and 6.55 respectively at the time of the survey. The median duration of olfactory and gustatory dysfunctions was 15 days and 12 days, respectively, with 0.5% (121/24 096) of patients experiencing these dysfunctions for more than 28 days. The overall self-reported improvement rate of smell and taste dysfunctions was 59.16% (14 256/24 096). Gender(OR=0.893, 95%CI: 0.839-0.951), SARS-CoV-2 vaccination status (OR=1.334, 95%CI: 1.164-1.530), history of head and facial trauma(OR=1.180, 95%CI: 1.036-1.344, P=0.013), nose (OR=1.104, 95%CI: 1.042-1.171, P=0.001) and oral (OR=1.162, 95%CI: 1.096-1.233) health status, smoking history(OR=0.765, 95%CI: 0.709-0.825), and the persistence of accompanying symptoms (OR=0.359, 95%CI: 0.332-0.388) were correlated with the recovery of olfactory and taste dysfunctions related to SARS-CoV-2 (above P<0.001 except for the indicated values). Conclusion: The incidence of olfactory and taste dysfunctions related to infection with the SARS-CoV-2 Omicron strain is high in mainland China, with females and young people more likely to develop these dysfunctions. Active and effective intervention measures may be required for cases that persist for a long time. The recovery of olfactory and taste functions is influenced by several factors, including gender, SARS-CoV-2 vaccination status, history of head and facial trauma, nasal and oral health status, smoking history, and persistence of accompanying symptoms.
Female ; Humans ; Adolescent ; SARS-CoV-2 ; Smell ; COVID-19/complications* ; Cross-Sectional Studies ; COVID-19 Vaccines ; Incidence ; Olfaction Disorders/etiology* ; Taste Disorders/etiology* ; Prognosis

气味是评价食品新鲜度最重要的参数之一。当气味以其自然浓度存在时，会在嗅觉系统中引发不同的神经活动模式。本研究提出了一种通过检测食物气味进行食物检测与评价的在体生物传感系统。我们通过将多通道微电极植入在清醒大鼠嗅球的僧帽/丛状细胞层上，进而对神经信号进行实时检测。结果表明，不同的气味可以引起不同的神经振荡活动，每个僧帽/丛状细胞会表现出特定气味的锋电位发放模式。单个大鼠的少量细胞携带足够的信息，可以根据锋电位发放频率变化率的极坐标图来区分不同储存天数的食物。此外，研究表明气味刺激后，β振荡比γ振荡表现出更特异的气味响应模式，这表明β振荡在气味识别中起着更重要的作用。综上，本研究提出的在体神经接口为评估食品新鲜度提供了一种可行性方法。
Olfactory Bulb ; Odorants ; Smell

Olfaction and food intake are interrelated and regulated. In the process of feeding, the metabolic signals in the body and the feeding signals produced by food stimulation are first sensed by the arcuate nucleus of hypothalamus and the nucleus tractus solitarius of brain stem, and then these neurons project to the paraventricular nucleus of hypothalamus. The paraventricular nucleus transmits the signals to other brain regions related to feeding and regulates feeding behavior. In this process, olfactory signals can be transmitted to hypothalamus through olfactory bulb and olfactory cortex to regulate feeding behavior. At the same time, gastrointestinal hormones (ghrelin, insulin, leptin, etc.) and some neurotransmitters (acetylcholine, norepinephrine, serotonin, endocannabinoid, etc.) produced in the process of feeding act on the olfactory system to regulate olfactory function, which in turn affects the feeding itself. This review summaries the research progress of the interaction between olfaction and food intake and its internal mechanism from the aspects of neuronal and hormonal regulation.
Arcuate Nucleus of Hypothalamus/metabolism* ; Feeding Behavior/physiology* ; Hypothalamus ; Paraventricular Hypothalamic Nucleus ; Smell