Four odorants for olfactory training are enough: a pilot study.

BACKGROUND:  Olfactory training (OT) is commonly used for the treatment of olfactory disorders. Nevertheless, there is an ongoing debate about the most effective OT regimen. We aimed to compare the effects of OT with 7 items (rose, lemon, eucalyptus, cloves, stewed apple, balm, mint) to 4-item-OT (rose, lemon, eucalyptus, cloves) over 3 months. Methods: Participants were 40 patients with olfactory dysfunction receiving 4-item-OT or 7-item-OT and 60 gender- and age-matched individuals with normal sense of smell receiving no OT, 4-item-OT, or 7-item-OT. Before and after the OT we assessed n-butanol odor thresholds, discrimination, and identification (TDI score), additionalthresholds for (R)-(-)-carvone, ß-damascenone, salicyclic acid benzylester, the degree of phantosmia and parosmia, cognitive function, and ratings of olfactory function. Results: In both patient groups, the TDI score increased with the use of OT, regardless of the number of odors used (p < 0.001; 3.48 ± 4.21 and lower than control groups). The clinically significant increase of 5.5 points in TDI score correlated with change of ratings of parosmia (r 0.62; p < 0.01) and with ratings of olfactory dysfunction (r = 0.51; p < 0.05). CONCLUSION:  Concluding, OT over a 3-months period with 4 or 7 odors appears to produce similar results, although the sample size has to be considered.

Investigating the efficacy of melatonin, topical sodium citrate, and multivitamin with zinc as a potential treatment for postinfectious loss of smell.

OBJECTIVES: Upper respiratory tract infections, including COVID-19, are associated with olfactory dysfunction and there is a need for novel therapeutic approaches. The aim of study was evaluating the effectiveness of adding melatonin, multivitamin and sodium citrate to olfactory training for the treatment of olfactory loss caused by COVID-19. METHODS: We evaluated olfactory function using University of Pennsylvania Smell Identification Test (UPSIT ®) scores and self-reported patient outcomes in post-infectious smell loss cases. We investigated the effectiveness involved olfactory training combined with sodium citrate, melatonin, and multivitamin supplements with zinc over a three-month period compared to an olfactory training alone. RESULTS: A total of 66 patients were included, with 33 in each group. There was no significant difference in the proportion of participants who showed improvement in UPSIT scores between the groups (OR = 1.43, 95% CI 0.43-4.8, p =  0.56). Both groups showed improvement in average test scores, but there were no significant differences in self-reported olfactory ability or discomfort with olfactory loss. Qualitative symptoms, such as parosmia and phantosmia, were reported by a similar proportion in both groups before and after the treatment (p =  0.11, p =  1, respectively). CONCLUSIONS: Olfactory training alone and olfactory training with associated with melatonin, multivitamins and topical sodium citrate did not show significant differences in improving olfactory function in post-COVID-19 patients.

Comparison of smoking conventional cigarettes and using heated tobacco products on the olfactory and gustatory function in healthy young adults: A cross-sectional study.

INTRODUCTION: Smoking has a negative impact on the chemosensory function. The aim of the study was to evaluate the effects of smoking experience and type of tobacco products on gustatory and olfactory function. METHODS: This study included 30 conventional cigarette smokers, 30 heated tobacco products (HTPs) users, and 30 non-smokers. Olfactory function was assessed with a 'Sniffin' Sticks Screening 12 Test' while the taste function was assessed with 'taste strips' for the basic tastes of sweet, sour, salty, and bitter. The lifetime exposure to smoking was calculated using the Brinkman index (BI). RESULTS: Conventional cigarette smokers demonstrated decreased olfactory function in comparison to non-smokers (median: 10 vs 11; p=0.001) but HTPs users did not differ between those two groups. Overall gustatory function was lower in conventional cigarette smokers (median: 9.5) and HTPs users (median: 10) than in non-smokers (median: 14; p<0.001). A difference was detected in the sour, salty and bitter taste but without significant difference between HTPs users and conventional cigarette smokers. Negative linear correlations were found between the BI and olfactory function, overall gustatory function, sour, salty, and bitter taste (r= -0.317 - -0.585; p≤0.002). In multiple linear regression, BI was the only predictor of olfactory dysfunction when controlling for the effect of tobacco products, age, and gender accounting for 11% of variance (p=0.024, R2=0.123). For gustatory dysfunction, BI was the strongest predictor followed by gender and tobacco products accounting for 11%, 5%, and 4% (p<0.001, R2=0.259). CONCLUSIONS: Olfactory and gustatory function are adversely associated with smoking, more depending on BI than tobacco product.

Determinants of Persistence and Recovery of Chronic COVID19 Chemosensory Dysfunction.

BACKGROUND: In 2-4% of patients, COVID19 chemosensory dysfunction (CSD) persists beyond six months, accounting for up to 4 million people in the US. The predictors of persistence and recovery require further exploration. OBJECTIVE: To define the predictors of recovery and assess the quality of CSD in registry subjects with self-reported persistent smell and taste dysfunction after COVID19. METHODS: COVID19 CSD participants (n=408) from the four major waves of the pandemic completed questionnaires at four time points between 2021 and 2023, assessing demographics, sinonasal symptoms and self-assessed recovery. Objective measurements of smell (UPSIT) and taste (BWETT) were performed on a sub-cohort (n=108). RESULTS: In this chronic CSD cohort, the average symptom duration was 24±5 months but 70% those who contracted COVID19 in 2020 have ongoing dysfunction. Phantosmia and dysgeusia were most prevalent in the early waves of COVID19, while most participants reported disrupted ability to distinguish scents and flavors and undulating chemosensory function. Subjects reported low incidence of subjective sinonasal symptoms but high prevalence of sleep and mood disturbance. Cigarette phantom smells were predictive of persistence of CSD. Conversely, self-reported environmental allergies were predictive of recovery and dust mite allergies, specifically, were negative predictors of cigarette phantom smells. Finally, no treatment resolved CSD, but nasal steroids were reported effective by recovered CSD subjects. Objective measures of both smell and taste were significantly reduced in chronic CSD compared to controls. CONCLUSIONS: Chronic COVID19 CSD is a syndrome resistant to standard anti-inflammatory therapy. Pre-existing environmental allergies and hypertension predict recovery, while cigarette smoke phantosmia predicts persistence.

The role of black soldier fly in eliminating the putrid odor of organic waste and its product application - A comprehensive review.

Organic waste including food garbage (FG) forms a major part of man-made problems that are highly associated with global pollution. This includes emission of greenhouse gases (GHGs) and foul odor which negatively affect human health. Interestingly, bioconversion of FG by black soldier fly larvae (BSFL) has been reported to reduce foul odors released from decaying FG. This paper will give overview on the potential of BSFL in lowering putrid odors from FGs. Thus, various bioconversion treatment methods of managing FG including were compared and discussed. The life cycle and role of BSF in reducing putrid odors from biowastes were also discussed in detail. Lastly, the potential utilization of BSFL in controlling odors and GHGs as well as the economic value of products derived from BSFL bioconversion were also discussed. BSFL inoculation slightly reduces odor compounds by modifying odor-producing compounds and microbes in FG. However, BSFL effectiveness is highly influenced by FG decomposition rate.

Identification of odor-active compounds in Nile tilapia (Oreochromis niloticus) from recirculated aquaculture systems: A case study with different depuration procedures.

Off-flavors are a major challenge for companies using recirculated aquaculture systems (RAS). In the presented work, we comprehensively characterize the odorant composition of Nile tilapia (Oreochromis niloticus) raised in RAS and compare the impact of two depuration processes on the odorant composition and aroma profile of the fish. Fish collected from the production tank and after two different tank pre-disinfection approaches in the depuration process (high pH versus H2O2) were investigated. A combined sensory-instrumental investigation revealed the presence of 115 odorants, of which 83 were successfully identified. The compounds decanal, tridecanal, (Z)-1,5-octadien-3-one, octane-2,3-dione, benzophenone, non-3-yn-1-ol, γ-dodecalactone, (Z)-geranylacetone, 2,3-diethyl-5-methylpyrazine, 1-methylpyrrolidin-2-one, 2-acetyl-2-thiazoline, benzothiazole, skatole, and 5α-androst-16-en-3-one were detected with the highest flavor dilution factors and are described for the first time as odor-active compounds in fish from RAS. The results indicate that depuration decreased the levels of 78 different odorants from the fish, including the potent earthy smelling odorants geosmin, isoborneol and 2,3-diethyl-5-methylpyrazine.

Cystic fibrosis-related chronic rhinosinusitis: the key role of a comprehensive evaluation in the era of highly effective modulator therapy.

BACKGROUND: Chronic rhinosinusitis (CRS) is prevalent in cystic fibrosis (CF), significantly affecting quality of life. The introduction of CFTR modulators, including elexacaftor-tezacaftor-ivacaftor (ETI), offers promise for improving sinonasal outcomes. METHODS: We conducted a retrospective cohort multicenter study analyzing electronic medical records of 45 adult CF patients with CRS, predominantly heterozygous for the ΔF508 mutation, treated with ETI between January 2018 and December 2023. Assessments included Sinonasal Outcome Test 22 (SNOT-22), Nasal Polyp Score (NPS), modified Lund-Kennedy Score (mLKS), Lund-Mackay Score (LMS), and olfactory function using smell loss visual analog scale (VAS) and Sniffin' Sticks identification test (SSIT). RESULTS: After 12 months of ETI therapy, significant improvements were observed in pulmonary function parameters (FEV1, FVC), CRS severity scores (SNOT-22, NPS, mLKS), radiological findings (LMS), and olfactory function. Subgroup analysis suggested enhanced efficacy in patients with prior endoscopic sinonasal surgery. CONCLUSIONS: ETI therapy demonstrates comprehensive improvements in CRS and olfactory function in CF patients, highlighting the potential of CFTR modulators in managing sinonasal manifestations.

Machine learning predictive modeling of the persistence of post-Covid19 disorders: Loss of smell and taste as case studies.

The worldwide health crisis triggered by the novel coronavirus (COVID-19) epidemic has resulted in an extensive variety of symptoms in people who have been infected, the most prevalent disorders of which are loss of smell and taste senses. In some patients, these disorders might occasionally last for several months and can strongly affect patients' quality of life. The COVID-19-related loss of taste and smell does not presently have a particular therapy. However, with the help of an early prediction of these disorders, healthcare providers can direct the patients to control these symptoms and prevent complications by following special procedures. The purpose of this research is to develop a machine learning (ML) model that can predict the occurrence and persistence of post-COVID-19-related loss of smell and taste abnormalities. In this study, we used our dataset to describe the symptoms, functioning, and disability of 413 verified COVID-19 patients. In order to prepare accurate classification models, we combined several ML algorithms, including logistic regression, k-nearest neighbors, support vector machine, random forest, extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM). The accuracy of the loss of taste model was 91.5 % with an area-under-cure (AUC) of 0.94, and the accuracy of the loss of smell model was 95 % with an AUC of 0.97. Our proposed modelling framework can be utilized by hospitals experts to assess these post-COVID-19 disorders in the early stages, which supports the development of treatment strategies.

The relationship between social odour awareness and emotional contagion susceptibility in females.

Previous research has shown a strong link between our sense of smell and emotion. More recently, the importance we attach to olfaction has been found to relate to our susceptibility to 'catch' the emotions of others. We explore this further by examining the relation between a newly developed measure of olfaction (social odour scale, SOS), which measures awareness of social odours, and emotional contagion susceptibility in female participants. The study therefore aimed to test the strength of this relationship and also help validate the English language version of the SOS. Female (n = 148) participants completed an online study that measured odour awareness [SOS; important of odour questionnaire, IOQ] and emotional contagion (EC). We found that the English version of the SOS yielded high reliability and supported the previous factor structure of the scale; additionally, we demonstrated a strong association between the SOS and IOQ which provides criterion validity for its usage. The study also revealed that whilst both the SOS and IOQ were positively associated with EC, the SOS was the more accurate predictor. These findings provide further validation for the use of the SOS and suggest that our subjective awareness of olfaction, especially concerning 'social odours' is an accurate predictor of emotional contagion.

A Study on the Effects of Hypothyroidism on the Senses: A Comprehensive Narrative Review.

Hypothyroidism has been found to have long-term effects on each of the senses, but with proper treatment, many of them can be significantly minimized. This paper analyzes the research on the impact of hypothyroidism on the senses of smell, taste, hearing, vision, and thermoregulation. Data were collected from the National Library of Medicine, PubMed, and Google Scholar databases using the keywords "hypothyroidism," "taste," "smell," "vision," "hearing," and "thermoregulation." Approximately 413 articles were found when searching with these parameters, and 30 were used in this paper. Studies were excluded if they were outside this paper's scope or older than 2012. Studies were included if they specifically focused on hypothyroidism and one of the five listed senses. Patients with hypothyroidism had a significantly increased risk of sensorineural hearing loss, decreased perception of the blue-yellow color axis, decreased sense of olfaction and number of olfactory bulbs, and decreased thermogenesis. Hypothyroidism was also found to show increased length of COVID-19-induced anosmia and decreased bitter taste perception. It can be concluded that hypothyroidism has many effects on the senses, particularly an increased risk of sensorineural hearing loss. More studies need to be done on these effects.

Olfactory perceptual fingerprints of people with olfactory dysfunction and healthy controls.

Objectives: An olfactory perceptual fingerprint (OPF) defines one's olfactory perception using perceptual descriptor ratings (such as odor pleasantness, intensity) for a set of odors. OPFs have been shown to distinguish patients with COVID-related olfactory dysfunction (OD) and healthy controls with 86% accuracy. However, all participants rated the same odorants. With the aim to evaluate whether the OPFs are indeed odorant independent, previously published dataset by Lötsch et al. was reanalyzed. Furthermore, this independent dataset was used to check whether the OPFs separate patients with OD due to various causes from controls. Methods: The study included 104 controls and 42 patients, who were randomized into four odor sets with 10 odorants each. Odorants were presented using a computer-controlled olfactometer and evaluated on scales from 1 (not at all) to 5 (very) using perceptual descriptors pleasant, intensive, familiar, edible, irritating, cold/warm, and painful. Results: Permutational multivariate analysis of variance showed that the odor set did not have a significant effect on the OPFs, confirming that the OPFs are indeed odorant independent. On the other hand, both diagnosis and age affected the OPFs (p < .001) and explained around 11% and 5% of the variance of the OPFs, respectively. Furthermore, a supervised machine learning method, random forest classifier, showed that OPF can distinguish patients and controls with 80% accuracy. Conclusion: OPFs are odorant independent. Patients perceived odors as less familiar, less intense, and less edible than controls. Other perceptual descriptors were much less important for the separation of patients and controls. Level of evidence: 3.

[Development and validation of Russian olfactory test]. / Otechestvennyi obonyatel'nyi test: razrabotka i validizatsiya.

Olfactory disorders is one of the first symptoms of diseases from various departments of medicine (otorhinolaryngology, psychology, neurology, etc.). Based on international clinical recommendations, olfactory tests are the gold standard for the diagnosis of olfactory disorders. There are many different psychophysical tests: UPSIT (USA, Pennsylvania), Sniffin' Sticks test (Germany), BAST-24 (Spain), etc. Currently, there is an acute shortage of olfactory tests available for clinical practice In Russia. This problem is related to the fact that there are no olfactory tests registered as medical devices on the territory of the Russian Federation. Also, a significant limitation is the unrecognizability of odors by the population of our country, which include foreign analogues (licorice, anise, turpentine, etc.). OBJECTIVE: To develop and validate the national olfactory test on healthy volunteers. MATERIAL AND METHODS: The development and validation of the olfactory test included several stages. First, the development of an olfactory test was carried out, the selection of aromas to assess the threshold and identification ability of olfaction. 25 dilutions of n-butanol were used for the assessment of the threshold olfactory ability. For the stage of assessing the identification ability of the sense of smell, in our previous study, an assessment of the recognition of odor names in the territory of the Russian Federation was carried out. A total of 3.000 people from 8 federal districts of the Russian Federation were interviewed. During the development of the test, 20 names of flavors with the highest rating were used. By the 8th, the selection of monocomponent substances was carried out. Commercially available certified food and perfume flavorings have been used for fragrances whose equivalent in the test cannot be a monocomponent substance. A group of 25 healthy volunteers selected a flavor or a monocomponent for each of the 20 positions. To carry out the identification stage of testing, a booklet was developed with answer options for each fragrance, including 80 images associated with the smell. A methodology for conducting diagnostics has been created. Next, the validation of the developed olfactory test was carried out on 150 healthy volunteers. The study included an assessment of the threshold and identification ability of the sense of smell using the developed test and conducting a comparative analysis with a set of flavors and descriptors corresponding to the Sniffin' Sticks test. RESULTS: The developed test includes: 2 panels - panel 1 to assess the threshold ability of smell, panel 2 to assess the identification ability of smell, a booklet with 80 images and captions to them. The norms of threshold and identification olfactory abilities were also determined in the developed test. The domestic test was validated against the relative foreign Sniffin' Sticks test. Spearman's correlation between the accuracy values of the domestic test (17-20; 85.00-100.00%) and the values of the foreign test (11-16; 68.75-100.00%) did not reveal statistically significant differences (rs=0.065, p=0.432), which confirms the equally effective assessment of olfactory ability by the domestic olfactory test in comparison with its foreign counterpart. CONCLUSION: In this work, a methodology for the use of Russian olfactory test was developed and validated on healthy volunteers. The features of the developed test are an assessment of the threshold and identification ability of smell, an adapted set of odors for the Russian population, the use of paper blotters when applying flavor and visual images of descriptors. Despite the wide variety of psychophysical tests, this problem requires further study and comparative analysis of olfactory tests available In Russia and foreign analogues in order to obtain a universal and effective diagnostic method for the populations of our country.This work was supported by the Russian Foundation for Basic Research (Project No. 24-25-00415).

Smell and taste disorders in childhood: Diagnostic challenges and significant impacts on a child's well-being.

AIM: Smell and taste are senses that contribute to a child's overall well-being. Disorders affecting these senses can impact a child's daily life from enjoying meals to detecting potential dangers through scent. The aim of this study is to describe patient characteristics and etiological causes of olfactory (OD) and/or gustatory disorders (GD) in children referred to a smell and taste clinic. Secondly, we aim to suggest a clinical work up. METHODS: Retrospective study where data were collected from 57 children who were referred consecutively to the University Clinic for Flavour, Balance, and Sleep; Department of Otorhinolaryngology (ORL), Head and Neck Surgery; Goedstrup Hospital, Denmark, for assessment due to OD/GD from January 2017 to May 2023. RESULTS: Most of the children had anosmia (60 %), whereas sensation of the basic tastes was intact in all but eight children (16 %). The lowest TDI scores were in children with congenital OD. The underlying etiology was congenital followed by postinfectious mostly related to Covid-19. Picky eating including anorectic traits were seen in 16 % of patients. CONCLUSION: The focus on smell loss in pediatric population is low, and probably does not adequately reflect either underlying prevalence in this group or the possible consequences on a child's well-being. Moreover, increased awareness of children's smell and taste loss is needed, as it may be associated with eating disturbances.

Preclinical Evaluation of Sodium Butyrate's Potential to Reduce Alcohol Consumption: A Dose-Escalation Study in C57BL/6J Mice in Antibiotic-Enhanced Binge-Like Drinking Model.

INTRODUCTION: In our earlier efforts to establish gut-brain axis during alcohol use disorder (AUD), we have demonstrated that supplementation of C57BL/6J male mice with 8 mg/mL sodium butyrate, a major short-chain fatty acid, in drinking water reduced ethanol intake and neuroinflammatory response in antibiotic (ABX)-enhanced voluntary binge-like alcohol consumption model, drinking in the dark (DID). METHODS: To further evaluate the preclinical potential of SB, we have set a dose-escalation study in C57BL/6J male mice to test effects of ad libitum 20 mg/mL SB and 50 mg/mL SB and their combinations with ABX in the DID procedure for 4 weeks. Effects of these SB concentrations on ethanol consumption and bodily parameters were determined for the duration of the treatments. At the end of study, blood, liver, and intestinal tissues were collected to study any potential adverse effects ad to measure blood ethanol concentrations. RESULTS: Increasing SB concentrations in the drinking water caused a loss in the protective effect against ethanol consumption and produced adverse effects on body and liver weights, reduced overall liquid intake. The hypothesis that these effects were due to aversion to SB smell/taste at these high concentrations were further tested in a follow up proof-of-concept study with intragastric gavage administration of SB. The higher gavage dose (320 mg/kg) caused reduction in ethanol consumption without any adverse effects. CONCLUSION: Overall, these findings added more support for the therapeutic potential of SB in management of AUD, given a proper form of administration.

The olfactory test established by Henkin: is it reliable and does it correlate to established psychophysical tests?

PURPOSE: This pilot study aimed to determine whether the Henkin olfactory test discriminates between the olfactory function of patients with olfactory loss and healthy individuals, and whether the Henkin test is correlated with a validated psychophysical olfactory test. METHODS: Participants underwent olfactory testing using the modified Henkin test (including detection [DT] and recognition [RT] thresholds, magnitude estimation [ME], and hedonic ratings [H], for four different odors) and the extended "Sniffin' Sticks" test battery (odor detection, discrimination, identification). RESULTS: Forty-four individuals (28 women, aged 19-81 years, mean: 39 years) were included. Twenty-three were healthy (mean age: 38 years) and 21 had olfactory dysfunction (OD) (mean age: 40 years). OD patients had worse mean DT, lower composite RT, and lower ME ratings. Mean and individual odor H ratings were not significantly different between the groups. Most individuals were classified as hyposmic when using the prescribed classification by Henkin, with only very few satisfying the stringent criteria of anosmia and normosmia. Modified Henkin subtests were all positively correlated with each other and with the "Sniffin' Sticks", except for Unpleasant Mean H which was only correlated with Pleasant Mean H; and Pleasant mean H which was not correlated with mean DT scores. CONCLUSION: The Henkin test is able to separate between OD patients and controls. However, modifications to the conduct of this test may be required. Studies that used this test should be carefully interpreted.

Olfactory training: perspective from people who were disturbed by their smell problems.

PURPOSE: Olfactory training (OT) is an effective and affordable option in the treatment of olfactory dysfunction. Despite significant progress in the field in recent years, some factors influencing OT participation remain unclear. METHODS: Based on an anonymous online survey orchestrated by AbScent.org the present study enrolled 450 participants and divided them into OT (n = 161) and No OT (n = 289) groups based on their OT participation. Participants also provided information on demographics, medical history, quality of life, OT duration for those who engaged in OT, and the reasons for non-participation in OT among those who did not. RESULTS: Patients who had greater loss of quality of life participated more in OT. Similarly, more participation was observed in patients who noticed an improvement in their ability to smell. Notably, most of the sample engaged in OT trained less than four weeks (73%). In the No OT group, the primary barrier to OT participation was the unawareness of OT treatment (37%) and these barriers differed by age, where older people expressed interest but were unaware of OT treatment, while younger individuals exhibited more cautiousness about its effectiveness. CONCLUSION: Lower quality of life drives active OT participation. Limited training periods and unawareness of OT serve as potential barriers to olfactory recovery. Clinicians should actively promote the background of OT and underscore the significance of adhering to the "prescribed" training regimen.

Short-term efficacy of platelet-rich plasma in the treatment of persistent olfactory dysfunction: systematic review and meta-analysis.

PURPOSE: To assess the short-term effects of topical platelet-rich plasma (PRP) injection on persistent refractory olfactory dysfunction. METHODS: A comprehensive literature search of the PubMed, SCOPUS, EMBASE, Web of Science, Google Scholar, and Cochrane databases was conducted for articles up to November 2023. The search focused on studies that compared the amelioration of olfactory dysfunction between a topical PRP treatment cohort and a control group (receiving either placebo or no treatment), along with pre- and post-treatment comparisons. Subgroup analysis of the evaluation of olfactory function was also performed. RESULTS: The improvement in olfactory scores 1-3 months post-treatment (standardized mean difference = 1.5354 [95% confidence interval: 0.7992; 2.2716], I2 = 83.8%) was greater in the treatment group than in the control group. In the treatment group, PRP increased the threshold, discrimination, and identification (TDI) score for Sniffin' Sticks by > 5.5 (minimum clinically significant difference; mean difference = 6.1789 [3.9788; 8.3789], I2 = 0.0%), indicating clinically significant improvement based on verified examinations. The rate of significant improvement among patients was 0.6683 [0.5833; 0.7436] after treatment. All TDI subdomains were significantly and similarly improved after treatment. CONCLUSION: This meta-analysis suggests that injection of PRP into the olfactory fissure or surrounding mucosal areas is an effective treatment for persistent refractory olfactory dysfunction in the short term.

Human perception of Parkinson's disease body odor in comparison to the volatile organic compounds of Parkinson's disease.

INTRODUCTION: Patients with Parkinson's Disease (PD) have a distinctive body odor, which was first described by a patient's wife as musky and strong. Later analysis of sebum of patients with PD revealed four volatile organic compounds (VOC) (perillic aldehyde, hippuric acid, eicosane, octadecanal), that differed from healthy subjects, and the patient's wife confirmed that three of them smelled like patients with PD. However, it is unclear whether other people can also perceive this PD body odor and whether it can be artificially recreated. Hence, we aimed to systematically assess whether young women can perceive the PD body odor and whether they can discriminate between the PD body odor and the "artificial PD odor" composed of the four VOCs mentioned above. METHODS: T-shirts were collected from 19 people with idiopathic PD and 15 age- and gender-matched healthy participants to represent the PD body odor and the healthy body odor, respectively. The four VOCs were diluted in 1,2-propanediol to prepare the artificial PD body odor. Body odors were rated by 26 young women. RESULTS: PD body odor was perceived as more musty, strong, smelly, and unpleasant compared to healthy and artificial PD body odor. Furthermore, around 80 % of women were able to discriminate PD body odor from artificial PD body odor. CONCLUSION: Overall, this study confirmed a distinctive body odor quality of patients with PD, which can be perceived by young women. However, the four VOCs, composing the artificial PD body odor, were insufficient to reproduce the body odor from PD patients.

Synaptic Connectivity and Electrophysiological Properties of the Nucleus of the Lateral Olfactory Tract.

The sense of smell is tightly linked to emotions, a link that is thought to rely on the direct synaptic connections between the olfactory bulb (OB) and nuclei of the amygdala. However, there are multiple pathways projecting olfactory information to the amygdala, and their unique functions are unknown. The pathway via the nucleus of the lateral olfactory tract (NLOT) that receives input from olfactory regions and projects to the basolateral amygdala (BLA) is among them. NLOT has been very little studied, and consequentially its function is unknown. Furthermore, formulation of informed hypotheses about NLOT function is at this stage limited by the lack of knowledge about its connectivity and physiological properties. Here, we used virus-based tracing methods to systematically reveal inputs into NLOT, as well as NLOT projection targets in mice of both sexes. We found that the NLOT is interconnected with several olfactory brain regions and with the BLA. Some of these connections were reciprocal, and some showed unique interhemispheric patterns. We tested the excitable properties of NLOT neurons and the properties of each of the major synaptic inputs. We found that the NLOT receives powerful input from the piriform cortex, tenia tecta, and the BLA but only very weak input from the OB. When input crosses threshold, NLOT neurons respond with calcium-dependent bursts of action potentials. We hypothesize that this integration of olfactory and amygdalar inputs serves behaviors that combine smell and emotion.

Noninvasive Diagnostic Method to Objectively Measure Olfaction and Diagnose Smell Disorders by a Molecularly Targeted Fluorescence Imaging Agent.

Despite the recent advances in understanding the mechanisms of olfaction, no tools are currently available to noninvasively identify loss of smell. Because of the substantial increase in patients presenting with coronavirus disease 2019-related loss of smell, the pandemic has highlighted the urgent need to develop quantitative methods. Methods: Our group investigated the use of a novel fluorescent probe named Tsp1a-IR800P as a tool to diagnose loss of smell. Tsp1a-IR800P targets sodium channel 1.7, which plays a critical role in olfaction by aiding the signal propagation to the olfactory bulb. Results: Intuitively, we have identified that conditions leading to loss of smell, including chronic inflammation and coronavirus disease 2019, correlate with the downregulation of sodium channel 1.7 expression in the olfactory epithelium, both at the transcript and at the protein levels. We demonstrated that lower Tsp1a-IR800P fluorescence emissions significantly correlate with loss of smell in live animals-thus representing a potential tool for its semiquantitative assessment. Currently available methods rely on delayed subjective behavioral studies. Conclusion: This method could aid in significantly improving preclinical and clinical studies by providing a way to objectively diagnose loss of smell and therefore aid the development of therapeutic interventions.