Odor Perception Research Articles

Comparing molecular representations, e-nose signals, and other featurization, for learning to smell aroma molecules.

Recent research has attempted to predict our perception of odorants using Machine Learning models. The featurization of the olfactory stimuli usually represents the odorants using molecular structure parameters, molecular fingerprints, mass spectra, or e-nose signals. However, the impact of the choice of featurization on predictive performance remains poorly reported in direct comparative studies. This paper experiments with different sensory features for several olfactory perception tasks. We investigate the multilabel classification of aroma molecules in odor descriptors. We investigate single-label classification not only in fine-grained odor descriptors ('orange', 'waxy', etc.), but also in odor descriptor groups. We created a database of odor vectors for 114 aroma molecules to conduct our experiments using a QCM (Quartz Crystal Microbalance) type smell sensor module (Aroma Coder®V2 Set). We compare these smell features with different baseline features to evaluate the cluster composition, considering the frequencies of the top odor descriptors carried by the aroma molecules. Experimental results suggest a statistically significant better performance of the QCM type smell sensor module compared with other baseline features with F1 evaluation metric.

Developmental changes in food and non-food odor importance – Data from Scotland and Pakistan

Developmental changes in objective olfactory abilities are well-documented, but the subjective importance of odors and olfaction from a developmental perspective has received less scientific interest. Here, in Scotland and Pakistan, we tested the importance of olfaction in 704 respondents (48.9% females) aged between 5 and 75 years old using a novel questionnaire. The scale comprised 18 items targeting six main functions of odor perception: appetite and regulation of food intake, pathogen and hazard avoidance, mating, social relations, bonding, and sensual pleasure. We found that the importance of olfaction was well-developed in children and often exceeded that of the adult samples. Notably, the ingestion-related element of olfactory importance seems to be observable from an early age. Our findings complement and advance the theory of human olfactory learning and help us understand the significance of smells from a developmental perspective.

Odor Hedonic Profile (OHP): a self-rating tool of everyday odors.

Odor hedonic estimation (pleasant/unpleasant) is considered the first and one of the most important dimensions in odor perception. Although there are several published scales that rate odor hedonicity, most of them use odorants that induce biases related to stimulus properties or test conditions and make difficult clinical or industrial applications. Thus, this study aimed to propose a model of odor hedonic profile (OHP) based on 14 items related to everyday odors without stimulus. The OHP is a self-rating tool based on the hedonic estimate representation and allows the determination of specific profiles, i.e., "conservative," "neutral," "liberal," "negative olfactory alliesthesia," and "positive olfactory alliesthesia." It can be useful in different contexts (e.g., food studies) and general pathologies (e.g., eating disorders) or pathologies with mood/emotional disturbances (e.g., depression).

Brain and antennal transcriptomes of host ants reveal potential links between behaviour and the functioning of socially parasitic colonies.

Insect social parasites are characterized by exploiting the hosts' social behaviour. Why exactly hosts direct their caring behaviour towards these parasites and their offspring remains largely unstudied. One hypothesis is that hosts do not perceive their social environment as altered and accept the parasitic colony as their own. We used the ant Leptothorax acervorum, host of the dulotic, obligate social parasite Harpagoxenus sublaevis, to shed light on molecular mechanisms underlying behavioural exploitation by contrasting tissue-specific transcriptomes in young host workers. Host pupae were experimentally (re-)introduced into fragments of their original, another conspecific, heterospecific or parasitic colony. Brain and antennal mRNA was extracted and sequenced from adult ants after they had lived in the experimental colony for at least 50 days after eclosion. The resulting transcriptomes of L. acervorum revealed that ants were indeed affected by their social environment. Host brain transcriptomes were altered by the presence of social parasites, suggesting that the parasitic environment influences brain activity, which may be linked to behavioural changes. Transcriptional activity in the antennae changed most with the presence of unrelated individuals, regardless of whether they were conspecifics or parasites. This suggests early priming of odour perception, which was further supported by sensory perception of odour as an enriched function of differentially expressed genes. Furthermore, gene expression in the antennae, but not in the brain corresponded to ant worker behaviour before sampling. Our study demonstrated that the exploitation of social behaviours by brood parasites correlates with transcriptomic alterations in the central and peripheral nervous systems.

The potential of almonds, hazelnuts, and walnuts SFE-CO2 extracts as sources of bread flavouring ingredients.

Nuts have been part of the human diet since our early ancestors, and their use goes beyond nutritional purposes, for example, as aromatic sources for dairy products. This work explores the potential of almond (Prunus dulcis (Mill.) DA Webb), hazelnut (Corylus avellana L.), and walnut (Juglans regia L.) extracts as sources of food flavouring agents, suggesting a new added-value application for lower quality or excess production fruits. The extracts were obtained by supercritical fluid extraction with carbon dioxide and characterized by: quantification of the volatile fraction by HS-SPME GC-MS; sensory perception and description; and cytotoxicity against Vero cells. All extracts revealed potential as flavouring ingredients due to terpene abundance. No significant differences were observed for the minimal sensory perception, in which the odour threshold values ranged from 8.3×10-4 to 6.9×10-3 μg·mL-1 for walnuts and almonds extracts, respectively. In contrast, the cytotoxic potential differed significantly among the extracts, and P. dulcis extract presented lower cytotoxicity. Notes as woody, fresh, and green were identified in the volatile intensifiers obtained from the P. dulcis extract. Thus, almond extract was identified as the most promising ingredient to increase the sensory value of food products, namely bread. This potential was verified by an increase in the odour perception of bread after adding 4μL of extract to each 100g of bread dough. The quantified eucalyptol and d-limonene terpenes - found in the P. dulcis extract - have improved the release of the pleasant and natural volatile compounds from bread crust and crumb compared to the control bread chemical and sensory profiles.

New Insights on Antennal Sensilla of Anastrepha ludens (Diptera: Tephritidae) Using Advanced Microscopy Techniques.

Using light, transmission, scanning electron, and confocal microscopy, we carried out a morphological study of antennal sensilla and their ultrastructures of the Mexican Fruit Fly Anastrepha ludens (Loew), an economically important species that is a pest of mangos and citrus in Mexico and Central America. Our goal was to update the known information on the various sensilla in the antennae of A. ludens, involved in the perception of odors, temperature, humidity, and movement. Based on their external shape, size, cuticle-thickness, and presence of pores, we identified six types of sensilla with 16 subtypes (one chaetica in the pedicel, four clavate, two trichoid, four basiconic, one styloconic, and one campaniform-like in the flagellum, and three additional ones in the two chambers of the sensory pit (pit-basiconic I and II, and pit-styloconic)), some of them described for the first time in A. ludens. We also report, for the first time, two types of pores in the sensilla (hourglass and wedge shapes) that helped classify the sensilla. Additionally, we report a campaniform-like sensillum only observed by transmission electronic microscopy on the flagellum, styloconic and basiconic variants inside the sensory pit, and an "hourglass-shaped" pore in six sensilla types. We discuss and suggest the possible function of each sensillum according to their characteristics and unify previously used criteria in the only previous study on the topic.

Short-term particulate matter contamination severely compromises insect antennal olfactory perception

The consequences of sub-lethal levels of ambient air pollution are underestimated for insects, for example, the accumulation of particulate matter on sensory receptors located on their antennae may have detrimental effects to their function. Here we show that the density of particulate matter on the antennae of houseflies (Musca domestica) collected from an urban environment increases with the severity of air pollution. A combination of behavioural assays, electroantennograms and transcriptomic analysis provide consistent evidence that a brief exposure to particulate matter pollution compromises olfactory perception of reproductive and food odours in both male and female houseflies. Since particulate matter can be transported thousands of kilometres from its origin, these effects may represent an additional factor responsible for global declines in insect numbers, even in pristine and remote areas.

Efficacy and safety of molnupiravir in adult outpatients with COVID-19

Background: One of the basic principles for the treatment of COVID-19 patients is the early initiation of etiotropic therapy. The evidence base for assessment of the efficacy and safety of antivirals for COVID-19 continues to expand with new clinical trials. One of the promising etiotropic medications is molnupiravir.
 Aim: To evaluate the efficacy and safety of molnupiravir (Esperavir) in outpatients with COVID-19.
 Materials and methods: This randomized comparative open-label clinical study was conducted from December 1, 2021 to March 11, 2022 in 12 research centers in the Russian Federation. The study involved 240 outpatients with mild and moderate COVID-19. The mean age of patients was 43.5 years; 70,0% (168/240) of the patients had comorbidities, mainly obesity grade II and arterial hypertension. The outpatients were treated with molnupiravir (Esperavir, PROMOMED RUS LLC, Russia) in 4 capsules 200 mg twice daily (every 12 hours), with the single dose being 800 mg and the daily dose 1600 mg. Duration of treatment was 5 days. The patients were followed up for 28 days. The patients in the standard treatment group (n = 120) received antiviral therapy recommended for outpatients by the provisional guidelines effective at the time of the study. Pathogenetic and symptomatic therapy in both groups was comparable.
 Results: The results of the clinical study in 240 outpatients with mild or moderate COVID-19 showed that molnupiravir at a dose of 800 mg twice daily for 5 days significantly reduced (by 4-hold at days 1415 of the follow-up) the risk of disease progression to more severe course, compared with the standard therapy group (2.5% (3/120) and 10.0% (12/120) of patients; p = 0.0149.) By days 67 of the follow-up, the virus had been eliminated in 71.67% of the patients treated with the study drug and only in 58.3% (70/120) of the patients in the standard therapy group. Complete clinical recovery at days 67 was achieved in 19.2% (23/120) of the patients in the molnupiravir group, compared to 5.8% (7/120) in the standard therapy group. Compared to the standard therapy, treatment with molnupiravir also significantly reduced the frequency and severity of the disease symptoms, such as cough and change in odor or taste perception over the last 24 hours, already at 67 days after the start of treatment. Molnupiravir treatment was well tolerated, most adverse events were mild. There were no cases of drug withdrawal or dose modification of the study drug due to adverse events.
 Conclusion: The results of the clinical study of antiviral agent molnupiravir (Esperavir) have proven its benefits over standard therapy in outpatients with mild and moderate COVID-19 in terms of the disease worsening risk reduction and hospitalization, the rate of viral elimination, the changes in symptoms severity over time, improvement of the patients general status and clinical condition and reduction of COVID-19 complications both in patients without and with risk factors for severe COVID-19 outcomes. The results of this study demonstrated a favorable safety profile of molnupiravir in COVID-19 patients.

Olfactory brain activations in patients with Major Depressive Disorder

Depression is associated with reduced olfactory function. This relationship is assumed to be based on either a reduced olfactory bulb volume or diminished functioning of higher cortical areas. As previous results are controversial, we aimed to re-evaluate central olfactory processing in depression. We recorded the BOLD signal of 21 patients with Major Depressive Disorder and 21 age and gender matched healthy controls during odor presentation. In addition, we measured the individual olfactory bulb volume, tested odor identification and odor threshold, and asked for hedonic odor perception. In both groups, odor presentation led to a pronounced activation of primary olfactory areas. However, secondary olfactory areas were significantly less activated in depressed individuals. The two groups did not differ in olfactory bulb volume. Our results point towards altered olfactory processing in patients in those regions that relate to sensory integration and attention allocation. Difficulties in cognitive processing could impact olfactory function in depression. We are therefore in favor of a top-down mechanism originating in higher cortical areas explaining parts of the relation between depression and olfaction.

An olfactory-based Brain-Computer Interface: electroencephalography changes during odor perception and discrimination.

Brain-Computer Interfaces (BCIs) are devices designed for establishing communication between the central nervous system and a computer. The communication can occur through different sensory modalities, and most commonly visual and auditory modalities are used. Here we propose that BCIs can be expanded by the incorporation of olfaction and discuss the potential applications of such olfactory BCIs. To substantiate this idea, we present results from two olfactory tasks: one that required attentive perception of odors without any overt report, and the second one where participants discriminated consecutively presented odors. In these experiments, EEG recordings were conducted in healthy participants while they performed the tasks guided by computer-generated verbal instructions. We emphasize the importance of relating EEG modulations to the breath cycle to improve the performance of an olfactory-based BCI. Furthermore, theta-activity could be used for olfactory-BCI decoding. In our experiments, we observed modulations of theta activity over the frontal EEG leads approximately 2 s after the inhalation of an odor. Overall, frontal theta rhythms and other types of EEG activity could be incorporated in the olfactory-based BCIs which utilize odors either as inputs or outputs. These BCIs could improve olfactory training required for conditions like anosmia and hyposmia, and mild cognitive impairment.

Roles of GOBP1 in perception of host plant volatiles revealed by CRISPR/Cas9‐mediated mutagenesis in Spodoptera litura

AbstractThe general odorant‐binding proteins (GOBPs) in Lepidoptera form a distinct OBP subclass, which exclusively has two members (GOBP1 and GOBP2) in a single species. GOBPs are long thought to function in perception of plant odorants and recently in sex pheromones, but the in vivo evidence is rarely provided. Here, by using CRISPR/Cas9 technique, we demonstrated that GOBP1 in a noctuid moth Spodoptera litura is involved in perception of host plant volatiles but not of the female sex pheromone, and GOBP1 in females is less important than GOBP2 in host plant perception. First, the GOBP1 knockout strain (GOBP1−/−) of S. litura was obtained by CRISPR/Cas9 technique. Second, in the electroantennography (EAG) tests, GOBP1−/− females displayed significant reduction in responses to plant volatile farnesene, and leaf discs of the host plant cabbage (males only to high leaf doses), but GOBP1−/− adults did not show significant EAG reduction to the major sex pheromone component and two pheromone analogues. Third, compared with GOBP2−/− females, GOBP1−/− females were significantly lower in reduction (in relation to WT moths) of EAG response to host plant leaves. Our results provide in vivo evidence that GOBP1 is involved in perception of host plant volatiles but is less important than GOBP2 in S. litura.

Alexithymia modulates the attitudes towards odors but not the olfactory abilities or the affective reactions to odors.

Although emotion and olfaction are closely linked, only a few studies have investigated olfactory processing in alexithymia, a condition characterized by altered emotional processing. These results do not allow comprehensive conclusions on whether individuals with alexithymia present lower olfactory abilities or only altered affective reactions and awareness of odors. Three pre-registered experiments were conducted to clarify this relation. We assessed olfactory functions, the affective qualities of odors, the awareness of odors, the attitudes towards them, and the ability to form olfactory images in the mind. Bayesian statistics were used to assess differences between low, medium and high alexithymia groups, and Linear Mixed Models (LMMs) were applied to investigate the modulation of the affective and cognitive components of alexithymia. We observed that individuals with a high level of alexithymia presented the same olfactory abilities, and did not show differences in their rating of odors compared to individuals with low alexithymia levels, while they reported lower levels of social and common odor awareness and a more indifferent attitude towards odors. Olfactory imagery was not affected by alexithymia level, and the affective and cognitive components of alexithymia, when considered separately, modulated olfactory perception differently. Learning more about olfactory perception in individuals with alexithymia leads to a better understanding of how alexithymia impacts the perception of hedonic stimuli coming from different sensory modalities. Our results imply that treatment goals for alexithymia should be the enhancement of the conscious perception of odors, supporting the use of mindfulness-based protocols in the alexithymia treatment.

Molecular mechanisms of caramel-like odorant-olfactory receptor interactions based on a computational chemistry approach

Molecular mechanisms of caramel-like odorant-olfactory receptor interactions were investigated based on molecular docking and molecular dynamics simulations. The transmembrane regions TM-3, TM-5 and TM-6 of receptors were main contributors of amino acid residues in the docking. Molecular docking results showed that hydrogen bonding and pi-pi stacking were the key forces for the stabilization of caramel-like odorants. The binding energies were positively correlated with the molecular weight of caramel-like odorants. Residues Asn155 (84%, OR2W1), Asn206 (86%, OR8D1), Ser155 (77%, OR8D1), Asp179 (87%, OR5M3), Val182 (84%, OR2J2) and Tyr260 (94%, OR2J2) with high frequencies played an important role in the complexes formation. Odorants 4-hydroxy-5-methylfuran-3(2H)-one (16#) and methylglyoxal (128#) were screened by molecular field-based similarity analysis, which tended to bind to the receptors OR1G1 and OR52H1 respectively, resulting a caramel-like aroma perception. The obtained results are useful for better understanding the perception of caramel-like odorants and their high-throughput screening.

Structural basis of amine odorant perception by a mammal olfactory receptor.

Odorants are detected as smell in the nasal epithelium of mammals by two G-protein-coupled receptor families, the odorant receptors and the trace amine-associated receptors1,2 (TAARs). TAARs emerged following the divergence of jawed and jawless fish, and comprise a large monophyletic family of receptors that recognize volatile amine odorants to elicit both intraspecific and interspecific innate behaviours such as attraction and aversion3-5. Here we report cryo-electron microscopy structures of mouse TAAR9 (mTAAR9) and mTAAR9-Gs or mTAAR9-Golf trimers in complex with β-phenylethylamine, N,N-dimethylcyclohexylamine or spermidine. The mTAAR9 structures contain a deep and tight ligand-binding pocket decorated with a conserved D3.32W6.48Y7.43 motif, which is essential for amine odorant recognition. In the mTAAR9 structure, a unique disulfide bond connecting the N terminus to ECL2 is required for agonist-induced receptor activation. We identify key structural motifs of TAAR family members for detecting monoamines and polyamines and the shared sequence of different TAAR members that are responsible for recognition of the same odour chemical. We elucidate the molecular basis of mTAAR9 coupling to Gs and Golf by structural characterization and mutational analysis. Collectively, our results provide a structural basis for odorant detection, receptor activation and Golf coupling of an amine olfactory receptor.

Antagonistic interactions between odorants alter human odor perception

The olfactory system uses hundreds of odorant receptors (ORs), the largest group of the G-protein-coupled receptor (GPCR) superfamily, to detect a vast array of odorants. Each OR is activated by specific odorous ligands, and like other GPCRs, antagonism can block activation of ORs. Recent studies suggest that odorant antagonisms in mixtures influence olfactory neuron activities, but it is unclear how this affects perception of odor mixtures. In this study, we identified a set of human ORs activated by methanethiol and hydrogen sulfide, two potent volatile sulfur malodors, through large-scale heterologous expression. Screening odorants that block OR activation in heterologous cells identified a set of antagonists, including β-ionone. Sensory evaluation in humans revealed that β-ionone reduced the odor intensity and unpleasantness of methanethiol. Additionally, suppression was not observed when methanethiol and β-ionone were introduced simultaneously to different nostrils. Our study supports the hypothesis that odor sensation is altered through antagonistic interactions at the OR level.

Metabolic activity organizes olfactory representations.

Hearing and vision sensory systems are tuned to the natural statistics of acoustic and electromagnetic energy on earth and are evolved to be sensitive in ethologically relevant ranges. But what are the natural statistics of odors, and how do olfactory systems exploit them? Dissecting an accurate machine learning model (Lee et al., 2022) for human odor perception, we find a computable representation for odor at the molecular level that can predict the odor-evoked receptor, neural, and behavioral responses of nearly all terrestrial organisms studied in olfactory neuroscience. Using this olfactory representation (principal odor map [POM]), we find that odorous compounds with similar POM representations are more likely to co-occur within a substance and be metabolically closely related; metabolic reaction sequences (Caspi et al., 2014) also follow smooth paths in POM despite large jumps in molecular structure. Just as the brain's visual representations have evolved around the natural statistics of light and shapes, the natural statistics of metabolism appear to shape the brain's representation of the olfactory world.

Mammalian evolution of human cis-regulatory elements and transcription factor binding sites.

Understanding the regulatory landscape of the human genome is a long-standing objective of modern biology. Using the reference-free alignment across 241 mammalian genomes produced by the Zoonomia Consortium, we charted evolutionary trajectories for 0.92 million human candidate cis-regulatory elements (cCREs) and 15.6 million human transcription factor binding sites (TFBSs). We identified 439,461 cCREs and 2,024,062 TFBSs under evolutionary constraint. Genes near constrained elements perform fundamental cellular processes, whereas genes near primate-specific elements are involved in environmental interaction, including odor perception and immune response. About 20% of TFBSs are transposable element-derived and exhibit intricate patterns of gains and losses during primate evolution whereas sequence variants associated with complex traits are enriched in constrained TFBSs. Our annotations illuminate the regulatory functions of the human genome.

Smell the Rainbow: Olfactory Intensity Changes Color, not Luminescence in a Synesthete (P2-9.011)

<h3>Objective:</h3> To inform how odor concentration may change color perception in a synesthete. <h3>Background:</h3> In a synesthete, different concentrations of the same odor inducing different colors has not heretofore been described. <h3>Design/Methods:</h3> <h3>Case Study:</h3> This 27-year-old right-handed single male presented with a lifelong history of odor-color synesthesia. Each odor is associated with a specific color. While odors induce perception of color, colors do not induce perception of odors. <h3>Results:</h3> Amyl acetate in concentrations diluted in USP grade mineral oil to 10%, 1%, 0.1% 0.01% (Moberg, 2003; Doty, 1995) was presented randomly six times. This demonstrated retest reliability as well as change in color as identified on the Hexadecimal Real Color Wheel (Jusko, 2022), as opposed to change in brightness, with the most intense, 10% and 1%: yellow; 0.1%: orchid; and 0.01%: light pink. This revealed change in intensity correlated with change in color as opposed to change in luminescence. <h3>Conclusions:</h3> Some odorants, when presented with higher concentration, induce perception of entirely different aromas, as occurs with hydrogen sulfide (Hirsch, 1996). This would be consistent with each percept of odor inducing its own color. Peradventure, the increased intensity of each of the odors may decrease the perception of brightness or luminance (Zellner, 2008). This, minimal but still discreet, well-defined inducers, precipitating superimposition of specific colors, may be viewed as a variant of synesthesia, a super-synesthete. This suggests the presence of an underlying synesthetic network hyperconnectivity with the V4 occipital lobe, the primary color area of the visual cortex (Gennaro, 2021), and the hippocampal representation of memory of aroma (White, 2015), or olfactory lobe (orbital frontal cortex and insular cortex) (Mauric, 2013), and V4 occipital lobe hyperconnection (Hubbard, 2005). Further exploration of such connections may reveal greater understanding of olfactory and visual system. <b>Disclosure:</b> Miss Brar has nothing to disclose. Dr. Hirsch has nothing to disclose.

Body odor disgust sensitivity (BODS) is related to extreme odor valence perception.

Odors are important disease cues, and disgust sensitivity to body odors reflects individual differences in disease avoidance. The body odor disgust sensitivity (BODS) scale provides a rapid and valid assessment of individual differences. Nevertheless, little is known about how individual differences in BODS might correlate with overall odor perception or how it is related to other differences in emotional reactivity (e.g., affect intensity). We investigated how BODS relates to perceptual ratings of pleasant and unpleasant odors. We aggregated data from 4 experiments (total N = 190) that were conducted in our laboratory, and where valence and intensity ratings were collected. Unpleasant odors were body-like (e.g., sweat-like valeric acid), which may provide disease cues. The pleasant odors were, in contrast, often found in soap and cleaning products (e.g., lilac, lemon). Across experiments, we show that individuals with higher BODS levels perceived smells as more highly valenced overall: unpleasant smells were rated as more unpleasant, and pleasant smells were rated as more pleasant. These results suggest that body odor disgust sensitivity is associated with a broader pattern of affect intensity which causes stronger emotional responses to both negative and positive odors. In contrast, BODS levels were not associated with odor intensity perception. Furthermore, disgust sensitivity to odors coming from external sources (e.g., someone else's sweat) was the best predictor of odor valence ratings. The effects were modest in size. The results validate the BODS scale as it is explicitly associated with experimental ratings of odor valence.

Could olfactory identification be a prognostic factor in detecting cognitive impairment risk in the elderly?

Aging contributes to the deterioration of the olfactory system in humans. Several studies indicate that the olfactory identification test alone may function as a screening test for olfactory dysfunction and they are more feasible to apply in clinical practice. Olfactory identification may be a predictor for cognitive impairment. Multiple studies have considered the use of odor identification as a measure to identify the conversion from normality to mild cognitive impairment or dementia. The objectives were (i) to elucidate the associations between cognitive status and olfactory identification performance in aging; (ii) understand the predictive value of olfactory capacity in identifying subjects with cognitive impairment risk; and (iii) to study how cognitive status and olfactory identification relate with other variables of wellness in aging, such as functional capabilities and clinical measures. For this purpose, a group of 149 participants (77.15 ± 7.29 years; 73 women of 76.7 ± 8 years and 76 men of 77.6 ± 6.52 years) were recruited and were subjected to a sociodemographic questionnaire, a psychological screening tool of general cognitive status, an olfactory identification evaluation, and clinical measures. The participants were divided into groups based on their cutoff scores of previous scientific reports about the Spanish version of Montreal Cognitive Assessment. Our results indicate an age-associated decline in olfactory identification ability and intensity of odor perception. The predictive ability of olfactory identification scores for the risk of mild and severe impairment is around 80%. Olfactory identification decreases with cognitive function. Performance in odor identification is associated with impairment of episodic memory and executive functions. These findings further our current understanding of the association between cognition and olfaction, and support olfactory assessment in screening those at higher risk of dementia.