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.

Turbinal bones are still one of the last frontiers of the tetrapod skull: hypotheses, challenges and perspectives.

Turbinals are bony or cartilaginous structures that are present in the nasal cavity of most tetrapods. They are involved in key functions such as olfaction, heat, and moisture conservation, as well as protection of the respiratory tract. Despite recent studies that challenged long-standing hypotheses about their physiological and genomic correlation, turbinals remain largely unexplored, particularly for non-mammalian species. Herein, we review and synthesise the current knowledge of turbinals using an integrative approach that includes comparative anatomy, physiology, histology and genomics. In addition, we provide synonyms and correspondences of tetrapod turbinals from about 80 publications. This work represents a first step towards drawing hypotheses of homology for the whole clade, and provides a strong basis to develop new research avenues.

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.

Disparity of turbinal bones in placental mammals.

Turbinals are key bony elements of the mammalian nasal cavity, involved in heat and moisture conservation as well as olfaction. While turbinals are well known in some groups, their diversity is poorly understood at the scale of placental mammals, which span 21 orders. Here, we investigated the turbinal bones and associated lamellae for one representative of each extant order of placental mammals. We segmented and isolated each independent turbinal and lamella and found an important diversity of variation in the number of turbinals, as well as their size, and shape. We found that the turbinal count varies widely, from zero in the La Plata dolphin, (Pontoporia blainvillei) to about 110 in the African bush elephant (Loxodonta africana). Multiple turbinal losses and additional gains took place along the phylogeny of placental mammals. Some changes are clearly attributed to ecological adaptation, while others are probably related to phylogenetic inertia. In addition, this work highlights the problem of turbinal nomenclature in some placental orders with numerous and highly complex turbinals, for which homologies are extremely difficult to resolve. Therefore, this work underscores the importance of developmental studies to better clarify turbinal homology and nomenclature and provides a standardized comparative framework for further research.

Olfaction Preservation and Long-term Outcomes in Patients with Unilateral Endoscopic Resection of Olfactory Neuroblastoma: A Systematic Review and Institutional Experience.

BACKGROUND: Endoscopic endonasal surgical resection is an effective therapeutic approach for olfactory neuroblastoma (ONB). Unilateral excision of ONBs with limited extension has been reported with the purpose of preserving olfactory function. We aimed to review implications of surgical management, olfactory preservation feasibility, and survival outcomes in patients who underwent endoscopic unilateral resection of olfactory neuroblastoma. METHODS: A systematic literature review was conducted using the search terms [("Olfactory neuroblastoma") OR ("Esthesioneuroblastoma")] AND [("Unilateral resection") OR ("Olfaction preservation")]. Studies reporting cases of unilateral olfactory neuroblastoma endoscopic resection with postoperative olfaction assessment were included. Concurrently, records of patients who met inclusion criteria at our institution were reviewed retrospectively. The survival and olfactory outcomes were analyzed in both cohorts. RESULTS: Thirty-three patients were identified in the published literature. Twenty-three (69.7%) reported postoperative olfaction preservation. Olfactory function after surgery did not show an association with Kadish stage (p=0.128). No evidence of disease was observed at the latest follow-up in this group of patients. Nine patients who met inclusion criteria were identified at our institution. The extent of resection influenced the level of olfaction preservation when cribriform plate and nasal septum resection coexisted (p=0.05). A single patient at our institution developed recurrence after being lost to follow-up for 22 months. CONCLUSIONS: Olfaction preservation can be achieved in patients who undergo endoscopic unilateral resection and adjuvant radiotherapy. The extent of resection should aim for negative margins, particularly in the midline. Larger studies are required to assess the risk of contralateral microscopic disease, and, hence, close follow-up is advised.

The Current Status and Challenges of Olfactory Dysfunction Study in Alzheimer's Disease.

Olfactory functioning involves multiple cognitive processes and the coordinated actions of various neural systems. Any disruption at any stage of this process may result in olfactory dysfunction, which is consequently widely used to predict the onset and progression of diseases, such as Alzheimer's Disease (AD). Although the underlying mechanisms have not yet been fully unraveled, apparent changes were observed in olfactory brain areas form patients who suffer from AD by means of medical imaging and electroencephalography (EEG). Olfactory dysfunction holds significant promise in detecting AD during the preclinical stage preceding mild cognitive impairment (MCI). Owing to the strong specificity, olfactory tests are prevalently applied for screening in community cohorts. And combining olfactory tests with other biomarkers may further establish an optimal model for AD prediction in studies of specific olfactory dysfunctions and improve the sensitivity and specificity of early AD diagnosis.

Narrative review on artificially intelligent olfaction in halitosis.

Halitosis, commonly known as oral malodor, is a multifactorial health concern that significantly impacts the psychological and social well-being of individuals. It is the third most frequent reason for individuals to seek dental treatment, after dental caries and periodontal diseases. For an in-depth exploration of the topic of halitosis, an extensive literature review was conducted. The review focused on articles published in peer-reviewed journals and only those written in the English language were considered. The search for relevant literature began by employing subject headings such as 'halitosis, oral malodor, volatile sulfur compounds, artificial intelligence, and olfaction' in databases such as PubMed/Medline, Scopus, Google Scholar, Web of Science, and EMBASE. Additionally, a thorough hand search of references was conducted to ensure the comprehensiveness of the review. After amalgamating the search outcomes, a comprehensive analysis revealed the existence of precisely 134 full-text articles that bore relevance to the study. Abstracts and editorial letters were excluded from this study, and almost 50% of the full-text articles were deemed immaterial to dental practice. Out of the remaining articles, precisely 54 full-text articles were employed in this review. As primary healthcare providers, dentists are responsible for diagnosing and treating oral issues that may contribute to the development of halitosis. To effectively manage this condition, dentists must educate their patients about the underlying causes of halitosis, as well as proper oral hygiene practices such as tongue cleaning, flossing, and selecting appropriate mouthwash and toothpaste. This narrative review summarises all possible AI olfaction in halitosis.

[Adaptation for use In Russia of the extended odor identification Sniffin' Sticks test]. / Kul'tural'naya adaptatsiya testa na identifikatsiyu zapakhov Sniffin' Sticks dlya ispol'zovaniya v Rossii.

The psychophysical Sniffin' Sticks test, which includes an odor identification test, is the gold standard for assessing the sense of smell in clinical and scientific practice. A necessary requirement for the odor identification test is a close familiarity with the odors used by the inhabitants of the region in which it is used. We studied 77 healthy volunteers and 51 patients with olfactory dysfunction and we found that Russians are not familiar with the three smells from the test (licorice, turpentine and anise) and are completely unfamiliar with the one proposed alternative answer (chives). Moreover, four odors demonstrated very low recognition (less than 75%). The test has been adapted for the use In Russia. In the booklet, licorice is replaced by cough syrup, turpentine by paint thinner, and chives by bay leaf. For odors with low recognition (lemon, apple, pineapple), the alternative fruity odors in the booklet were replaced with more contrasting ones. Based on the data obtained, we are going to develop a domestic version of the odor identification test.

The Context Matters: Women's Experiences of Their Partner's Odor in Intimate and Sexual Encounters.

Research shows that male body odor plays an important role in women's mate choice and that olfactory abilities are associated with women's sexual functioning. What remains unclear is what types of partner's odor actually shape women's experience during intimate activities. This study therefore explored women's experience associated with the partner's various odors and investigated how they affect women's intimate and sexual encounters. We performed semi-structured individual interviews with 20 single women and 20 women in a long-term relationship. Thematic analysis revealed four key natural odor types of the partner: body odor, sweat, genital odor, and semen odor. Further, we have identified three main types of fragrance odor (cologne, shower gel, and laundry agents) and investigated their perception in both intimate (hugging, kissing, cuddling, lying side by side) and sexual (intercourse, oral sex, ejaculation) contexts. Both partner's natural odor and fragrance affected women's emotional state (ranging from pleasant to unpleasant) and behavioral response (ranging from approach to avoidance of partner). Women's odor perception was frequently context-dependent, so that even mostly negatively perceived odors (e.g., semen, genital odor) were often accepted as part of sexual encounter. Finally, women's perception was negatively modified by partner's specific sweat (after workday, workout, or when the partner is ill) during intimate encounters. Our results highlight the complexity and interindividual variability of partner's odor perception.

Disparities in seeking care for olfactory and gustatory dysfunction: A population analysis.

INTRODUCTION: Despite effects on quality of life from olfactory and gustatory dysfunction (OD and GD), screening practices are limited, and patients' self-reporting of symptoms remains the only way to understand the burden of chemosensory dysfunction (CSD). Using a large population-based database, we sought to understand factors leading to reduced likelihood of discussing CSD with a provider. METHODS: The 2013‒2014 National Health and Nutrition Examination Survey (NHANES) chemosensory protocol was queried for factors influencing discussion of OD/GD with a healthcare provider. Sociodemographic, comorbidity, and objective OD/GD testing results were assessed with a multivariate analysis. RESULTS: Out of 146.1 million US adults, there were an estimated 41.4 million individuals with self-reported OD/GD in the prior 12 months (28.3%). A total of 86.8% of participants did not discuss their problem with a healthcare provider. Men were about half as likely to speak with a healthcare provider (odds ratio [OR] 0.42; 0.26-0.66; p < 0.001) and those with a college education were about nine times more likely to discuss the problem compared to those with less than a ninth-grade educational achievement (OR 8.83; 1.86-41.98; p = 0.02). Those with objective confirmation of CSD were still unlikely to speak with a provider (OR 0.77; 0.44-1.33; p = 0.36). CONCLUSION: Men and those with less education are less likely to discuss OD/GD with a healthcare provider. These populations tend to be at increased risk for CSD, and there are severe downstream health and quality of life implications related to CSD. Dedicated screening and increased public awareness are critical to ensure more equitable care.

Effect of physical activity on olfaction acuity: A systematic review.

Olfaction acuity, which includes detection thresholds, discrimination and identification, appears to decline with age, obesity, and various neurological disorders. Knowing that smell influences energy intake, there is a growing interest in protecting this sense. Physical activity could be a key intervention to counteract the loss of olfaction. This systematic review aims to explore the literature on the effect of physical activity on olfaction acuity. The search strategy consisted of using index terms and keywords in MEDLINE, EMBASE, EBM Reviews - Cochrane Central Register of Controlled Trials, CINAHL, SPORTDiscus, and Web of Science search engine. Data from 17 trials involving 10,861 participants showed that physical activity improved olfaction thresholds, discrimination, identification and perceived intensity. Regular practice of physical activity seemed to have better effects on olfaction components than acute exercise. Although this review has clarified the evidence on the effects of physical activity on olfaction, better methodological consistency is needed.

Multimodal interactions in Stomoxys navigation reveal synergy between olfaction and vision.

Stomoxys flies exhibit an attraction toward objects that offer no rewards, such as traps and targets devoid of blood or nectar incentives. This behavior provides an opportunity to develop effective tools for vector control and monitoring. However, for these systems to be sustainable and eco-friendly, the visual cues used must be specific to target vector(s). In this study, we modified the existing blue Vavoua trap, which was originally designed to attract biting flies, to create a deceptive host attraction system specifically biased toward attracting Stomoxys. Our research revealed that Stomoxys flies are attracted to various colors, with red proving to be the most attractive and selective color for Stomoxys compared to the other colors tested. Interestingly, our investigation of the cattle-Stomoxys interaction demonstrated that Stomoxys flies do not prefer a specific livestock fur color phenotype, despite variation in the spectrum. To create a realistic sensory impression of the trap in the Stomoxys nervous system, we incorporated olfactory cues from livestock host odors that significantly increased trap catches. The optimized novel polymer bead dispenser is capable of effectively releasing the attractive odor carvone + p-cresol, with strong plume strands and longevity. Overall, red trap baited with polymer bead dispenser is environmentally preferred.

JAK and STAT5B mediate olfactory response of migratory locusts to their own volatiles.

Janus kinase (JAK) and signal transducer and activator of transcription (STAT) signaling affect social aggregation, mood and psychiatric disorders, nociceptive and depressive behaviors. Olfactory dysfunction is one of the distinct symptoms of these behaviors, but function and mechanism of JAK and STAT in modulating olfaction remain largely unknown. Migratory locusts show olfactory preference for their own volatiles. We thus use this animal model to explore functions and mechanisms of JAK and STAT5B in mediating olfaction response to their own volatiles. Tissue distribution study shows that JAK and STAT5B express in antennae and brains, especially in antennal lobes and mushroom bodies in locust brains, and knockdown of these two genes by RNA interference (RNAi) in antennae and brains results in the loss of olfactory preference for locust volatiles, including chemical odorants indole and ß-ionone. RNA-seq analysis reveals that JAK and STAT5B RNAi knockdown downregulates a functional class of transcripts in nucleoprotein complex, including heterogeneous nuclear ribonucleoprotein C (hnRNPC) and small nuclear ribonucleoprotein polypeptide F (SNRPF). HnRNPC and SNRPF mRNAs and proteins are also expressed in antennae and brains, and RNAi knockdown of these two genes reduces the percentage of locusts preferring volatiles, including chemical odorants indole and ß-ionone. Furthermore, RNAi knockdown of dopamine receptor 1 (DopR1) results in the decrease of JAK mRNA level in antennae, and JAK/STAT5B, hnRNPC and SNRPF are required for dopamine receptor 1 (DopR1) to modulate olfactory preference for their own volatiles. This study confirms that JAK/STAT5B signaling modulates olfaction by affecting expression levels of hnRNPC and SNRPF, and this pathway is also required for DopR1 to modulate olfactory preference for their own volatiles. These findings highlight novel roles of JAK and STAT5B in modulating olfactory preference. This study provides novel insights into functional links among JAK/STAT5B signaling, RNA binding proteins and DopR1 underlying the modulation of olfactory behaviors.

Influence of visual information on sniffing behavior in a routinely trichromatic primate.

Most catarrhine primates are considered to be strongly visually oriented, obtaining information about conspecifics and their environment from a diversity of visual cues. Other sensory modalities may provide information that is redundant and/or complimentary to visual cues. When cues from multiple sensory modalities are available, these may reinforce or suppress each other, as shown in several taxa ranging from insects to humans. Here, we tested how the presence and ambiguity of visual information affect the use of olfactory cues when exploring food and non-food items in semi-free-ranging Barbary macaques at Affenberg Salem, Germany. We presented monkeys with pipes containing food (peanuts, popcorn), non-food (stones, feces), or no items in transparent or opaque containers and assessed whether animals looked, sniffed, and/or grabbed into the pipes depending on the visibility of the contents (experiment 1). Visual information had no robust effect on sniffing probability, but monkeys were more likely to sniff before any other form of inspection if the can was opaque than if it was transparent. Both visual and olfactory information affected, whether or not monkeys attempted to retrieve the items from the pipes, whereby monkeys showed an overall decrease in the propensity to grab after sniffing. Furthermore, we manipulated the visual appearance of familiar food items (popcorn) with food colorant (experiment 2), which resulted in substantially increased olfactory inspections compared to unmanipulated popcorn. Taken together, reliance on the olfactory sense was modulated by the available visual information, emphasizing the interplay between different sensory modalities for obtaining information about the environment.

Geosmin, a Food- and Water-Deteriorating Sesquiterpenoid and Ambivalent Semiochemical, Activates Evolutionary Conserved Receptor OR11A1.

Geosmin, a ubiquitous volatile sesquiterpenoid of microbiological origin, is causative for deteriorating the quality of many foods, beverages, and drinking water, by eliciting an undesirable "earthy/musty" off-flavor. Moreover, and across species from worm to human, geosmin is a volatile, chemosensory trigger of both avoidance and attraction behaviors, suggesting its role as semiochemical. Volatiles typically are detected by chemosensory receptors of the nose, which have evolved to best detect ecologically relevant food-related odorants and semiochemicals. An insect receptor for geosmin was recently identified in flies. A human geosmin-selective receptor, however, has been elusive. Here, we report on the identification and characterization of a human odorant receptor for geosmin, with its function being conserved in orthologs across six mammalian species. Notably, the receptor from the desert-dwelling kangaroo rat showed a more than 100-fold higher sensitivity compared to its human ortholog and detected geosmin at low nmol/L concentrations in extracts from geosmin-producing actinomycetes.

Changes in paranasal sinus volumes, temporal bone pneumatization, internal acoustic canal and olfactory cleft dimensions over the centuries: a comparison of skulls from different epochs in Anatolia.

OBJECTIVES: Investigating changes in temporal bone pneumatization (TBP) and paranasal sinus volumes (PSV) across different eras may help understanding not only changes in skull anatomy but also pathophysiology of chronic otitis media and sinusitis, respectively, which are common health problems. METHODS: Eight skulls from the second century AD, 20 skulls were from the 10th-11th centuries AD, 20 skulls from the 16th-19th centuries AD, and 60 contemporary skulls were included in this cross-sectional observational study. Using computerized tomography (CT) scans, the PSV were calculated by multiplying the height, width, and antero-posterior distance of the sinuses. TBP was divided into three types. Internal acoustic canal (IAC) length and width, and olfactory cleft (OC) width were measured. RESULTS: No statistically significant differences were found between the paranasal sinus (frontal, maxillary, and sphenoid) volumes between the groups. However, TBP decreased statistically significantly over time on both sides of the skulls (p = 0.001). The contemporary IAC and OC measures were found to be significantly lower on both sides compared to the skulls from the other three eras (p < 0.001 for both). CONCLUSIONS: Although no significant change was observed in PSV, decreases were evident in TBP, OC width and IAC length and width over time. It appears a fair inference that changes in size of OC and IAC might be another indication of the fact that olfaction and hearing were more vital for survival in old eras. Since we do not know incidence of chronic ear problems in old eras, we cannot speculate outcome of increased TBP in terms of developing chronic ear diseases. On the contrary, increased TBP was likely to play a protective role in traumas in old ears. Additionally, the environmental influences may be crucial role in the development of paranasal sinuses.

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

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

Multi-institutional validation of an AI-based sinus CT analytic platform with olfactory assessments.

KEY POINTS: AI-based CT sinus analysis may have advantages over visual based systems, for example, Lund-Mackay score. Here, we show multi-institutional validation of an AI algorithm using novel OMC classification. Significant, robust correlations are seen between algorithm outputs and clinical outcomes.

Validation of a rodent model of episodic memory replay.

Vivid episodic memories in humans have been described as the replay of the flow of past events in sequential order. Recently, Panoz-Brown et al. Current Biology, 28, 1628-1634, (2018) developed an olfactory memory task in which rats were presented with a list of trial-unique odors in an encoding context; next, in a distinctive memory assessment context, the rats were rewarded for choosing the second to last item from the list while avoiding other items from the list. In a different memory assessment context, the fourth to last item was rewarded. According to the episodic memory replay hypothesis, the rat remembers the list items and searches these items to find the item at the targeted locations in the list. However, events presented sequentially differ in memory trace strength, allowing a rat to use the relative familiarity of the memory traces, instead of episodic memory replay, to solve the task. Here, we directly manipulated memory trace strength by manipulating the odor intensity of target odors in both the list presentation and memory assessment. The rats relied on episodic memory replay to solve the memory assessment in conditions in which reliance on memory trace strength is ruled out. We conclude that rats are able to replay episodic memories.