Olfaction Research Articles

Transorbital Endoscopic Approach for Managing Challenging Frontal Sinus Lesions: Results and Operative Technique Description

Abstract Objective The aim of this study was to describe our experience using the transorbital endoscopic approach (TEA) in the frontal sinus and the step-by-step technique used. Materials and Methods We reviewed the charts from adult patients who underwent management of frontal sinus lesions with TEA performed from 2017 to 2022. Results Seven patients underwent eight surgeries for frontal sinus lesions using TEA in combination with the endoscopic transnasal approach (ETA), with the majority on the left side (5/8, 62.5%). The average age was 53.9 years, with six male patients and one female patient. Gross total resection (GTR) was achieved in all cases. The most common symptoms leading to surgery were headaches or a sensation of pressure in the forehead (5/8, 62.5%), followed by a decreased sense of smell (3/8, 37.5%), diplopia (3/8, 37.5%), proptosis (2/8, 20%), periorbital cellulitis (2/8, 20%), and decreased visual acuity (1/8, 12.5%). The most common etiology in this case series was mucocele (5/8, 62.5%), followed by osteoid osteoma (2/8, 20%), and inverted papilloma (1/8, 12.5%). The length of stay in all cases was 1 day. The most common complication was mild and transitory V1 numbness, which fully recovered after 6 months (5/8, 62.5%). The average follow-up period was 24.6 months (range of 3–48 months). Conclusion Transoral Endoscopic Approach (TEA) demonstrated being a valuable complement to ETA approaches for treating frontal sinus lesions, especially in challenging regions. The transorbital approach is feasible and can safely achieve GTR for a variety of pathologies while effectively controlling symptoms and resulting in a 1-day hospital stay.

Engineered odorant receptors illuminate the basis of odour discrimination.

How the olfactory system detects and distinguishes odorants with diverse physicochemical properties and molecular configurations remains poorly understood. Vertebrate animals perceive odours through G protein-coupled odorant receptors (ORs)1. In humans, around 400 ORs enable the sense of smell. The OR family comprises two main classes: class I ORs are tuned to carboxylic acids whereas class II ORs, which represent most of the human repertoire, respond to a wide variety of odorants2. A fundamental challenge in understanding olfaction is the inability to visualize odorant binding to ORs. Here we uncover molecular properties of odorant-OR interactions by using engineered ORs crafted using a consensus protein design strategy3. Because such consensus ORs (consORs) are derived from the 17 major subfamilies of human ORs, they provide a template for modelling individual native ORs with high sequence and structural homology. The biochemical tractability of consORs enabled the determination of four cryogenic electron microscopy structures of distinct consORs with specific ligand recognition properties. The structure of a class I consOR, consOR51, showed high structural similarity to the native human receptor OR51E2 and generated a homology model of a related member of the human OR51 family with high predictive power. Structures of three class II consORs revealed distinct modes of odorant-binding and activation mechanisms between class I and class II ORs. Thus, the structures of consORs lay the groundwork for understanding molecular recognition of odorants by the OR superfamily.

Ratting on wildlife crime: training African giant pouched rats to detect illegally trafficked wildlife

The illegal wildlife trade (IWT) is one of the largest global crime economies, directly threatening species and their habitats, and biodiversity, and indirectly the global climate, and countries’ economies. Syndicates operating within the IWT are often involved in trafficking of humans, weapons, and drugs. IWT takes place in large scale through international ports, with wildlife being smuggled inside shipping containers. Current methods to combat IWT and screen these shipping containers, such as X-ray scans, are expensive and time-consuming. Scent-detection animals present an innovative approach to combatting IWT, as animals may be better suited to distinguish between organic materials and less susceptible to visual concealment methods. Previous scent-detection work has largely focused on conservation dogs (Canis lupus familiaris). Here, we present a series of proof-of-principle studies training African giant pouched rats (Cricetomys ansorgei) to detect illegally trafficked wildlife. As initial proof-of-principle within a controlled laboratory environment, we trained rats (n=11) to detect the scent of pangolin scales (Manis spp.) and a threatened African hardwood (Dalbergia melanoxylon). In subsequent experiments, we trained these rats (n=10) to detect rhinoceros horn (family Rhinocerotidae), and elephant tusks (Loxodonta spp.). At the conclusion of these studies, rats (n=7) accurately identified all four target species (although ivory samples may have been cross-contaminated, and results should be interpreted with caution) while correctly rejecting non-target items commonly used by traffickers to conceal the presence of illicit material. Rats detected the presence of wildlife targets even when these were concealed in mixtures among non-target items. These results provide the foundation to train rats for scent-detection of illegally trafficked wildlife to combat IWT. The unique attributes of rats could allow them to complement existing screening technologies in the fight against IWT. Rats have low training and maintenance costs, flexibly work with multiple handlers, have a long lifespan, and a sophisticated sense of smell. Their small size also offers unique capabilities for the screening of shipping containers, such as being able to navigate densely packed areas or be lifted to assess contents of sealed containers by screening ventilation systems. Future directions include assessing operational feasibility of deploying rats at ports.

A Drosophila-inspired intelligent olfactory biomimetic sensing system for gas recognition in complex environments

The olfactory sensory system of Drosophila has several advantages, including low power consumption, high rapidity and high accuracy. Here, we present a biomimetic intelligent olfactory sensing system based on the integration of an 18-channel microelectromechanical system (MEMS) sensor array (16 gas sensors, 1 humidity sensor and 1 temperature sensor), a complementary metal‒oxide‒semiconductor (CMOS) circuit and an olfactory lightweight machine-learning algorithm inspired by Drosophila. This system is an artificial version of the biological olfactory perception system with the capabilities of environmental sensing, multi-signal processing, and odor recognition. The olfactory data are processed and reconstructed by the combination of a shallow neural network and a residual neural network, with the aim to determine the noxious gas information in challenging environments such as high humidity scenarios and partially damaged sensor units. As a result, our electronic olfactory sensing system is capable of achieving comprehensive gas recognition by qualitatively identifying 7 types of gases with an accuracy of 98.5%, reducing the number of parameters and the difficulty of calculation, and quantitatively predicting each gas of 3–5 concentration gradients with an accuracy of 93.2%; thus, these results show superiority of our system in supporting alarm systems in emergency rescue scenarios.

Powerful Patina: The Value of Odors in a Tibetan Buddhist Temple

ABSTRACT In the past decades, attention towards a more sensory perception in the arts and architecture has gained momentum and concerns a variety of disciplines. Nonetheless, hands-on conservation efforts still overwhelmingly concentrate on the visual qualities and values of places. In the following article, I present a case study of a Tibetan–Buddhist temple in Ladakh/India that empirically examines questions of value as they extend to the idea of patina found on wall paintings inside the temple produced by the burning of butter lamps. The layer of soot which obscures these centuries-old wall paintings has particular olfactory qualities. The paper draws from my professional and personal experience as art conservator working with an NGO from 2004 until 2014. It is a methodological re-thinking of our original conservation approach through the framework of Alois Riegl's value model applied to olfactory perceptions of patina. Examined are the meaning of odors concerning heritage values, memory, and the formation of identity. Odors are site-specific, therefore, conservation work at heritage sites needs to include the documentation and value assessment of their olfactory qualities to determine the impact a removal of patina may have on stakeholder communities.

Enriching Flaws of Scent عطر עטרה A Guava Scent Collection

Abstract This essay is written around the art-action عطر עטרה A Guava scent collection from an artist’s point of view. It connects the decision-making process and manifestations of the scent collection to dominant convictions about the “flaws” of scent and the sense of smell in Western philosophy. According to these convictions, the sense of smell and scent have no relevance to rational thinking and/or scientific knowledge and by implication to a political debate, for three reasons: scent is volatile, the sense of smell is non-verbal, and the sense of smell is too subjective to rely on. By contrast, I argue that the supposed “flaws” of scent and the sense of smell, might, in fact, contribute in a constructive and productive way to a sociopolitical debate, as will be demonstrated by the art installation of the Guava scent collection.

Olfactory Dysfunction in Obesity and Type 2 Diabetes

The article analyzes literature data on the close relationship between energy balance and sense of smell. Olfaction is one of the main modalities of hedonic evaluation of food. Odor is one of the most important sensory signals predicting food quality and plays a key role in food selection and consumption. Appetite can be stimulated by various stimuli, but the leading role belongs to olfactory signals (tasty smells) and levels of hormones that signal hunger and satiety. Olfactory perception is subject to hormonal modulation. In this regard, special attention in the article is paid to the modulating function of insulin. Insulin, one of the main metabolic hormones that controls food intake, has an anorexigenic effect not only at the level of the hypothalamus, but also at the level of the olfactory pathway, especially strong in the olfactory bulb. It has a rate of insulin transport two to eight times higher than in other parts of the brain, and it contains the highest concentration of insulin and the highest density of insulin receptor kinase. Thus, insulin is not only able to penetrate to the site of olfactory information processing, but do so quickly. At the same time, insulin and its receptors are localized in the olfactory epithelium, namely in mature olfactory sensory neurons. Therefore, insulin affects the primary stage of perception of an odorous molecule – odor detection, which occurs at the level of the olfactory epithelium. The sense of smell is impaired up to its complete loss in obesity and type 2 diabetes, worsening the quality of life of such patients. The paper examines the effectiveness of intranasal insulin administration to restore olfactory function in metabolic disorders and other diseases.

Hypogonadotropic hypogonadism as a cause of NOA and its treatment

Abstract Hypogonadotropic hypogonadism (HH) represents a relatively rare cause of nonobstructive azoospermia (NOA), but its knowledge is crucial for the clinical andrologists, as it represents a condition that can be corrected with medical therapy in 3 quarters of cases. There are forms of congenital HH, whether or not associated with an absent sense of smell (anosmic HH or Kallmann syndrome, and normosmic HH, respectively), and forms of acquired HH. In congenital HH, complete absence of pubertal development is characteristic. On the other hand, if the deficit occurs after the time of pubertal development, as in acquired HH patients, infertility and typical symptoms of late-onset hypogonadism are the main reasons for seeking medical assistance. Gonadotropin-releasing hormone (GnRH) or gonadotropin replacement therapy is the mainstay of drug therapy and offers excellent results, although a small but significant proportion of patients do not achieve sufficient responses.

Humans without a sense of smell breathe differently

Olfaction may play a restricted role in human behavior, yet paradoxically, its absence in anosmia is associated with diverse deleterious outcomes, culminating in reduced life expectancy. The mammalian nose serves two purposes: olfaction and breathing. Because respiratory patterns are impacted by odors, we hypothesized that nasal respiratory airflow may be altered in anosmia. We apply a wearable device that precisely logs nasal airflow for 24-hour-long sessions in participants with isolated congenital anosmia and controls. We observe significantly altered patterns of respiratory nasal airflow in anosmia in wake and in sleep. These differences allow classification of anosmia at 83% accuracy using the respiratory trace alone. Patterns of respiratory airflow have pronounced impact on health, emotion and cognition. We therefore suggest that a portion of the deleterious outcomes associated with anosmia may be attributed to altered patterns of respiratory nasal airflow rather than a direct result of lost odor perception per se.

Olfactory and gustatory chemical sensor systems in the African turquoise killifish: Insights from morphology.

Smell and taste are extensively studied in fish species as essential for finding food and selecting mates while avoiding toxic substances and predators. Depending on the evolutionary position and adaptation, a discrete variation in the morphology of these sense organs has been reported in numerous teleost species. Here, for the first time, we approach the phenotypic characterization of the olfactory epithelium and taste buds in the African turquoise killifish (Nothobranchius furzeri), a model organism known for its short lifespan and use in ageing research. Our observations indicate that the olfactory epithelium of N. furzeri is organized as a simple patch, lacking the complex folding into a rosette, with an average size of approximately 600µm in length, 300µm in width, and 70µm in thickness. Three main cytotypes, including olfactory receptor neurons (CalbindinD28K), supporting cells (β-tubulin IV), and basal cells (Ki67), were identified across the epithelium. Further, we determined the taste buds' distribution and quantification between anterior (skin, lips, oral cavity) and posterior (gills, pharynx, oesophagus) systems. We identified the key cytotypes by using immunohistochemical markers, i.e. CalbindinD28K, doublecortin, and neuropeptide Y (NPY) for gustatory receptor cells, glial fibrillary acidic protein (GFAP) for supporting cells, and Ki67, a marker of cellular proliferation for basal cells. Altogether, these results indicate that N. furzeri is a microsmatic species with unique taste and olfactory features and possesses a well-developed posterior taste system compared to the anterior. This study provides fundamental insights into the chemosensory biology of N. furzeri, facilitating future investigations into nutrient-sensing mechanisms and their roles in development, survival, and ageing.

Childhood trauma impacts internalizing problems in early adulthood: the affective implications of olfactory dysfunctions

Early detection and prevention of internalizing problems demand a thorough exploration of latent vulnerabilities before clinical symptoms emerge. Limited research attention has been paid to the influence of olfactory perception, a flexible factor intricately linked to emotional processing and external environmental factors. This study sought to examine the mediating role of olfactory function in the relationship between childhood trauma, encompassing both dimensions of child abuse and neglect, and internalizing problems. A total of 1661 individuals (801 males, Meanage = 21.67 years) participated in wave 1, with 327 participants (152 males, Meanage = 21.8 1 years) included in the follow-up wave 2 three months later. Online questionnaires, including the Childhood Trauma Questionnaire, Self-reported Olfactory Disorder Questionnaire, Beck Depression Inventory, and General Anxiety Disorder-7, were administered. Mediation tests were conducted using Mplus 8. Our findings revealed a significant mediating effect of olfactory dysfunction between childhood trauma and adult internalizing problems in wave 1 (B = 0.224, 95% CI [0.167, 0.294]). Childhood trauma heightened vulnerability to olfactory dysfunction (B = 0.721, 95% CI [0.671, 0.724]), subsequently exacerbating internalizing problems (B = 0.311, 95% CI [0.226, 0.408]). This effect persisted in longitudinal data (abuse: B = 0.686, p < 0.001; neglect: B = 0.200, p < 0.001). Regarding internalizing problems influenced by olfactory function, childhood abuse had a greater impact compared to childhood neglect (wave 1: χ2 = 56.012, p < 0.001; wave 2: χ2 = 5.156, p = 0.023). This study found that olfactory dysfunction mediated the relationship between childhood trauma and internalizing problems, contributing valuable insights into psychopathology and the early identification of symptoms related to internalizing problems.

Comparative analysis of chromosome-level genomes provides insights into chromosomal evolution in Chiroptera.

Chiroptera (bats) presents a fascinating model due to its remarkable variation in chromosome numbers, which range from 14 to 62. This astonishing diversity makes bats an excellent subject for studying chromosome evolution. The black-bearded tomb bat (Taphozous melanopogon) occupies a pivotal phylogenetic position within Chiroptera, emphasizing its crucial role in the systematic examination of bat chromosome evolution. In this study, we present the first chromosome-level genome of T. melanopogon within the family Emballonuridae. Together with previously published genomes, we construct a strongly supported phylogenetic tree of bats, which supports that Emballonuridae forms a basal group within Yangochiroptera. Furthermore, we reconstruct ancestral karyotypes at key nodes along the bat phylogeny and conduct a synteny analysis among the genomes of 12 bat species. Our findings identified evolutionary breakpoint regions (EBRs) that are of particular interest. Notably, some bat genomes exhibit an enrichment of genes related to host defense against microbial pathogens within EBRs. Remarkably, one species possesses multiple copies of some β-defensin genes, while six other species have experienced the loss of some β-defensin genes due to EBRs. Furthermore, some olfactory receptor genes are located in EBRs of 12 species, 4 of which have a significant enrichment in sensory perception of smell. Together, our comparative genomic analysis underscores the potential link between chromosome rearrangements and the adaptation of bats to defend against microbial pathogens.

Changes in weight secondary to improved odor perception in chronic rhinosinusitis with nasal polyps' patients treated with Dupilumab.

The advent of biologic therapies, notably Dupilumab, has transformed therapeutic approaches to nasal polyposis. This retrospective multicentric study aimed to investigate weight changes in CRSwNP patients undergoing Dupilumab treatment and explore potential correlations with olfactory improvement. Ninety-six patients with CRSwNP were followed for at least 12 months, with assessments including BMI (Body Mass Index), olfactory function, and disease severity. Significant increases in BMI and olfactory perception were observed after 1 year of Dupilumab treatment (p < .001). Subgroup analysis showed that patients with hyposmia and normosmia at T12 (1-year follow up) experienced significant weight gain (p < .001) alongside improved olfaction (both p < .001). Conversely, patients with anosmia after 1 year of therapy and also patients with stable or worsened olfaction did not show significant BMI changes (respectively p = .201 and p = .107). While these findings suggest a correlation between olfactory improvement and weight gain/BMI, factors like improved nasal airflow and corticosteroid cessation under Dupilumab treatment may also influence weight in CRPwNP patients. The study highlights the need for further research to elucidate the causal relationship and long-term implications of Dupilumab-induced olfactory improvement on weight regulation.

Human olfactory perception embeds fine temporal resolution within a single sniff.

A sniff in humans typically lasts one to three seconds and is commonly considered to produce a long-exposure shot of the chemical environment that sets the temporal limit of olfactory perception. To break this limit, we devised a sniff-triggered apparatus that controls odorant deliveries within a sniff with a precision of 18 milliseconds. Using this apparatus, we show through rigorous psychophysical testing of 229 participants (649 sessions) that two odorants presented in one order and its reverse become perceptually discriminable when the stimulus onset asynchrony is merely 60 milliseconds (Cohen's d = 0.48; 95% confidence interval, (55, 59); 120-millisecond difference). Discrimination performance improves with the length of stimulus onset asynchrony and is independent of explicit knowledge of the temporal order of odorants or the relative amount of odorant molecules accumulated in a sniff. Our findings demonstrate that human olfactory perception is sensitive to chemical dynamics within a single sniff and provide behavioural evidence for a temporal code of odour identity.

Multi-Sensory Interaction and Spatial Perception in Urban Microgreen Spaces: A Focus on Vision, Auditory, and Olfaction

As important recreational spaces for urban residents, urban microgreen parks enhance the urban living environment and alleviate psychological pressure on residents. The visual, auditory, and olfactory senses are crucial forms of perception in human interaction with nature, and the sustainable perceptual design of miniature green parks under their interaction has become a recent research hotspot. This study aimed to investigate the effects of the visual, acoustic, and olfactory environments (e.g., aromatic green vegetation) on human perception in miniature green parks. Participants were evenly divided into eight groups, including single-sensory groups, multi-sensory interaction groups, and a control group. Eye-tracking technology, blood pressure monitoring, and the Semantic Differential (SD) scales and Profile of Mood State (POMS) were used to assess the effectiveness of physical and mental perception recovery in each group. The results revealed that in an urban microgreen space environment with relatively low ambient noise, visual–auditory, visual–olfactory, and visual–auditory–olfactory interactive stimuli were more effective in promoting the recovery of visual attention than single visual stimuli. Additionally, visual–auditory–olfactory interactive stimuli were able to optimize the quality of spatial perception by using positive sensory inputs to effectively mask negative experiences. Simultaneously, environments with a high proportion of natural sounds had the strongest stimuli, and in the visual–auditory group, systolic blood pressure at S7 and heart rate at S9 significantly decreased (p &lt; 0.05), with reductions of 18.60 mmHg and 20.15 BPM, respectively. Aromatic olfactory sources were more effective in promoting physical and mental relaxation compared to other olfactory sources, with systolic blood pressure reductions of 24.40 mmHg (p &lt; 0.01) for marigolds, 23.35 mmHg (p &lt; 0.01) for small-leaved boxwood, and 27.25 mmHg (p &lt; 0.05) for camphor trees. Specific auditory and olfactory conditions could guide visual focus, such as birdsong directing attention to trees, insect sounds drawing attention to herbaceous plants, floral scents attracting focus to flowers, and leaf scents prompting observation of a wider range of natural vegetation. In summary, significant differences exist between single-sensory experiences and multi-sensory modes of spatial perception and interaction in urban microgreen parks. Compared to a silent and odorless environment, the integration of acoustic and olfactory elements broadened the scope of visual attention, and In the visual–auditory–olfactory interactive perception, the combination of natural sounds and aromatic camphor tree scents had the best effect on attention recovery, thereby improving the quality of spatial perception in urban microgreen parks.

Multi-channel portable odor delivery device for self-administered and rapid smell testing

To improve our understanding of the perception of odors, researchers are often required to undertake experimental procedures with users exposed to multiple odors in a variety of settings, including to diagnose smell loss in clinics and care homes. Existing smell tests are typically administered using multiple sniffing pens, manually presented to patients by a highly specialized nurse using a time-consuming and complex testing paradigm. Automated odor delivery devices, such as olfactometer systems, exist but are expensive, bulky and typically lab based, making them difficult to use for on the ground odor delivery. Here we have developed a portable, affordable, odor delivery device that can deliver 24 odors through individual channels with high temporal precision and without cross-contamination. The device allows for the rapid, flexible sequencing of odors via digital control using a mobile application and has been experimentally validated in the lab, as well as tested on patients. The design provides several advantages for investigating olfactory perception and offers the possibility that users can one day self-administer smell tests in a range of settings, including at home, allowing smell healthcare services to evolve and become part of a routine practice and self-care culture.

Orthonasal and retronasal olfactory function in patients with chronic rhinosinusitis without nasal polyps undergoing endoscopic sinonasal surgery.

Olfactory dysfunction (OD) is a key symptom of chronic rhinosinusitis (CRS). Although extensively studied in CRS with nasal polyps (CRSwNP), OD in CRS without nasal polyps (CRSsNP) remains under-researched. This study aims to assess the prevalence of OD and its evolution in surgically naïve patients with CRSsNP undergoing endoscopic sinus surgery (ESS). This prospective study included 97 participants with CRSsNP (mean age, 46.5 years; 70.1% men) and 97 healthy controls (mean age, 46.5 years; 70.1% men). Participants underwent psychophysical evaluations of orthonasal (using the Sniffin' Sticks test) and retronasal olfaction (using powdered aromas) at enrolment and 6 months post-ESS. Out of 97 patients, 81 (83.5%) completed all assessments. At enrolment, 23 (28.4%) CRSsNP patients had OD based on composite threshold, discrimination, identification scores, compared with 7 (8.6%) controls (absolute % difference, 19.8% [95% CI, 8.2-31.4]). Retronasal olfactory function was also significantly worse in CRSsNP patients. Six months post-ESS, 30 patients (37.0%) experienced a clinically significant improvement in olfactory, whereas nonsignificant changes were observed in retronasal olfactory score, and 3.7% of patients experienced a deterioration of the olfactory function. In conclusion, although 37% of patients experienced a clinically significant improvement in their sense of smell following ESS, the overall prevalence of OD in this surgically naive population appears relatively low, especially when compared to that observed in patients with CRSwNP. Therefore, ESS may offer some benefits for enhancing orthonasal olfactory function, but the extent of these improvements appears to be limited.

Monorhinal and Birhinal Odor Processing in Humans: an fMRI investigation.

The olfactory nerve, also known as cranial nerve I, is known to have exclusive ipsilateral projections to primary olfactory cortical structures. However, the lateralization of olfactory processes is known to depend on the task and nature of stimuli. It still remains unclear whether olfactory system projections in humans also correspond to functional pathways during olfactory tasks without any trigeminal, perceptual or cognitive-motor components. Twenty young healthy subjects with a normal sense of smell took part in an olfactory functional magnetic resonance imaging (fMRI) study. We used two types of nostril specific stimulation, passive (no sniffing) and active (with sniffing), with phenyl ethyl alcohol, a pure olfactory stimulant, to investigate fMRI activity patterns in primary and secondary olfactory-related brain structures. Irrespective of the stimulated nostril and the type of stimulation, we detected symmetrical activity in primary and secondary olfactory-related brain structures such as the primary olfactory cortex, entorhinal cortex, and orbitofrontal cortex. In the absence of perceptual or cognitive-motor task demands, the perception of monorhinally presented pure odors is processed bilaterally in the brain.

Visual placebo and nocebo effects.

Placebo and nocebo effects modulate symptom perception through expectations and learning processes in various domains. Predominantly, their impact has been investigated on pain and physical performance. However, the influence of placebos and nocebos on visual system functionality has yet to be explored. The present study aimed to test whether placebo and nocebo effects can intervene in altering participants' performance outcomes during a novel visual accuracy task and to examine the underlying neural mechanisms through EEG. After performing a baseline session, visual accuracy was said to be enhanced or disrupted by a sham transcranial electrical stimulation over the occipital lobe. Behavioural results showed a significant increase in visual accuracy for the placebo group, from the baseline session to the test session, whereas the nocebo group showed a decrease in visual accuracy. EEG analyses on the event-related potential P300 component, conducted on both a centro-parietal electrode patch and a parieto-occipital, one displayed an increase in the amplitude of P300 for the placebo group, and a decrease in the nocebo group. These findings suggest for the first time that placebo and nocebo effects can influence visual perception and attentional processes linked to it. Overall, the present study contributes to understanding how expectations affect sensory perception beyond pain and the motor system, paving the way for investigating these phenomena in other sensory modalities such as auditory or olfactory perception. KEY POINTS: Placebo and nocebo effects have been studied predominantly in pain and motor performance fields. In a novel visual task, the impact of placebo and nocebo effects on the visual system has been evaluated, in both early components (stimuli-related) and late components (attention-related). The placebo group showed an increase in visual accuracy and EEG-evoked potential amplitudes, whereas the nocebo group showed a decrease in both. This study shows how expectations and the related placebo and nocebo effects can shape basic stimuli sensory perception in the visual domain.

Reduced Sense of Smell in Patients with Severe Chronic Rhinosinusitis and its Implications for Diagnosis and Management: A Narrative Review.

Reduced sense of smell is a common symptom in patients with chronic rhinosinusitis (CRS). Although it is often under-diagnosed by healthcare providers, reduced sense of smell can have a substantial negative impact on patient's quality of life as measured by health-related quality of life (HRQoL) assessments and patient-reported outcomes. This narrative review describes current smell loss diagnosis and management guidelines in CRS, and the relationship between smell loss and CRS. Reduced sense of smell can be an indication of CRS disease severity in patients with (CRSwNP) and without nasal polyps (CRSsNP), and recovery of smell can be an indicator of successful CRS treatment. The current first-line therapeutic options for smell loss are intranasal corticosteroids and nasal irrigation, and second-line therapeutic options include systemic steroids and surgery. Shared decision-making between patient, caregiver, and healthcare provider is important when choosing the most appropriate CRS treatment option. Emerging biologic therapies that target type 2 inflammation signaling pathways, such as dupilumab, omalizumab, and mepolizumab, have been shown to improve smell and taste in randomized controlled trials of patients with CRSwNP.A graphical abstract and video abstract are available with this article.