Olfactory disorders and quality of life--an updated review

Associations between Taste and Smell Sensitivity, Preference and Quality of Life in Healthy Aging-The NutriAct Family Study Examinations (NFSE) Cohort

Taste and smell function decline with age, with robust impairment in the very old. Much less is known about taste and smell function in young and middle aged. We investigated taste and smell sensitivity via thresholds in a sub-sample of the NutriAct Family Study (NFS), the NFS Examinations cohort (NFSE; N = 251, age M = 62.5 years). We examined different aspects relating to taste and smell function: the degree to which taste and smell sensitivity relate to another and to taste and smell preferences, the role of gender and age, as well as effects on Quality of Life (QoL). Taste thresholds were highly correlated, but no correlation was observed between taste and smell thresholds and between thresholds and preference. Women were more sensitive for both taste and smell than men. We found no effect of age on sensitivity and no effect of sensitivity on QoL. All null findings were complemented by Bayesian statistics. Together our results indicate the independence of taste and smell despite their overlap during sensorial experiences. We found no evidence for age-related sensory decline, which could be due to our sample’s characteristics of non-clinical volunteers with good dental health and 93% non-smokers.

Treatment strategies for postviral olfactory dysfunction: A systematic review

Background: The coronavirus disease 2019 (COVID-19) pandemic has been associated with a dramatic increase in postviral olfactory dysfunction (PVOD) among patients who are infected. A contemporary evidence-based review of current treatment options for PVOD is both timely and relevant to improve patient care. Objective: This review seeks to impact patient care by qualitatively reviewing available evidence in support of medical and procedural treatment options for PVOD. Systematic evaluation of data quality and of the level of evidence was completed to generate current treatment recommendations. Methods: A systematic review was conducted to identify primary studies that evaluated treatment outcomes for PVOD. A number of medical literature data bases were queried from January 1998 to May 2020, with completion of subsequent reference searches of retrieved articles to identify all relevant studies. Validated tools for the assessment of bias among both interventional and observational studies were used to complete quality assessment. The summary level of evidence and associated outcomes were used to generate treatment recommendations. Results: Twenty-two publications were identified for qualitative review. Outcomes of alpha-lipoic acid, intranasal and systemic corticosteroids, minocycline, zinc sulfate, vitamin A, sodium citrate, caroverine, intranasal insulin, theophylline, and Gingko biloba are reported. In addition, outcomes of traditional Chinese acupuncture and olfactory training are reviewed. Conclusion: Several medical and procedural treatments may expedite the return of olfactory function after PVOD. Current evidence supports olfactory training as a first-line intervention. Additional study is required to define specific treatment recommendations and expected outcomes for PVOD in the setting of COVID-19.

Correlation between olfactory function, age, sex, and cognitive reserve index in the Italian population

Purpose

Loss of smell decreases the quality of life and contributes to the failure in recognizing hazardous substances. Given the relevance of olfaction in daily life, it is important to recognize an undiagnosed olfactory dysfunction to prevent these possible complications. Up to now, the prevalence of smell disorders in Italy is unknown due to a lack of epidemiological studies. Hence, the primary aim of this study was to evaluate the prevalence of olfactory dysfunction in a sample of Italian adults.

Methods

Six hundred and thirty-three participants (347 woman and 286 men; mean age 44.9 years, SD 17.3, age range 18–86) were recruited from 10 distinct Italian regions. Participants were recruited using a convenience sapling and were divided into six different age groups: 18–29 years (N = 157), 30–39 years (N = 129), 40–49 years (N = 99), 50–59 years (N = 106), > 60 years (N = 142). Olfactory function, cognitive abilities, cognitive reserve, and depression were assessed, respectively, with: Sniffin’ Sticks 16-item Odor Identification Test, Montreal Cognitive Assessment, Cognitive Reserve Index, and the Beck Depression Inventory. Additionally, socio-demographic data, medical history, and health-related lifestyle information were collected.

Results

About 27% of participants showed an odor identification score < 12 indicating hyposmia. Multiple regression analysis revealed that OI was significantly correlated with age, sex, and cognitive reserve index, and young women with high cognitive reserve index showing the highest olfactory scores.

Conclusion

This study provides data on the prevalence of olfactory dysfunction in different Italian regions.

Measured and self-reported olfactory function in voluntary Norwegian adults

Purpose

The lack of epidemiological data on the proportion of olfactory dysfunction (OD) using comprehensive olfactory assessment in healthy adults in Scandinavia motivated to the present study which aimed to explore the proportion of OD in voluntary healthy Norwegian adults, assessed by Sniffin’ Sticks, and its correlation to self-reported olfactory function. Furthermore, sociodemographic and clinical factors associated with olfactory function were analysed.

Methods

The sample included 405 Norwegian participants, aged 18–78 years, 273 women and 132 men, who underwent olfactory testing with extensive Sniffin’ Sticks test, allergy testing, clinical examination with nasal endoscopy and completed a self-administered questionnaire, including self-evaluation of olfactory function on a 100 mm Visual Analogue Scale.

Results

We found that 37% had OD, of which 1.2% had anosmia assessed with extensive Sniffin’ Sticks test. The proportion of hyposmia and anosmia increased with age. Men and participants with low education had poorer olfactory function scores. Allergy, smoking status, general health and endoscopic findings were not associated with measured olfactory function. We found no correlation between self-reported and measured olfactory function.

Conclusions

This study has identified that a large proportion of our sample of voluntary healthy Norwegian adults have OD, considerably more common in older adults and somewhat more common in men and individuals with low education. The lack of correlation between self-reported and measured olfactory function highlights the importance of using validated tests for a reliable olfactory evaluation.

Olfaction after endoscopic surgery for sellar and parasellar disease: an updated systematic review and meta-analysis

Background: Whether endoscopic surgery for sellar/parasellar disease causes significant deficits in olfactory function remains unclear. We aimed to systematically review the olfactory outcomes in such settings based on the evidence up to date. Methods: PubMed, EMBASE, and CENTRAL were searched through February 1, 2021. Included studies were limited to endoscopic surgery for sellar/parasellar disease with follow-up olfactory function measured by standardized olfactory testing methods or subjective assessment. The primary outcome was the change in olfactory function after surgery assessed by standardized olfactory testing methods. The secondary outcome was the change in subjective olfactory function. Random-effects model was used in obtaining combine effects. Study quality was assessed using the Newcastle–Ottawa scale. Sensitivity analysis was carried out using the leave-one-out approach, and publication bias was assessed using Egger’s test. Results: The results show no significant difference in olfaction assessed by standardized olfactory testing methods at 1–3 months post-surgery (880 patients in 16 studies) or at 6–12 months post-surgery (1320 patients in 16 studies) compared to pre-surgery, whereas a significantly lower subjective olfaction at 3 months was observed. In addition, the lack of significant change in olfaction as assessed by standardized olfactory testing methods was observed regardless of whether patients were treated with or without the nasoseptal flap (NSF) harvesting. Heterogeneity and publication bias were observed, whereas sensitivity analysis showed the meta-analysis results are robust. Conclusion: The findings of this updated systematic review and meta-analysis support the conclusion that endoscopic surgery for sellar and parasellar pathology may pose no greater risk of olfactory dysfunction. In addition, the current evidence does not support there is an increased risk of diminished olfaction among patients treated with NSF during surgery.

Danish Validation of a Retronasal Olfactory Powder Test and Development of a Novel Quick Retronasal Olfactory Test

Introduction  Quality of life is closely linked to retronasal olfactory function. Familiarity with odors vary, so tests need validation. Testing can be time-consuming, so a quick test and a thorough test are needed for clinical and research settings.

Objectives  The objectives of this study were to validate the original retronasal powder olfactory test in a Danish population and to develop a novel quick retronasal test for easy application.

Methods  Ninety-seven participants were included in the study, 59 healthy controls and 38 patients with olfactory impairment. The retronasal test was modified by substituting unfamiliar odors and descriptors and validated with a criterion of correct identification rate of 50% in the original test and 90% in the quick test. Items with over 90% correct identification rate in the modified original test were included in the quick test, resulting in a 10-item test.

Results  The modified retronasal olfactory test achieved good test characteristics, with a 10th percentile cut-off value of 13: sensitivity was 88.9%, specificity 83.0%, positive predictive value 78%, negative predictive value 91.7%, and the receiver operating characteristics area under the curve (ROC-AUC) was 0.86. The quick test achieved acceptable test characteristics, with a 10th percentile cut-off value of 8.2: sensitivity was 72.2%, specificity 90.6%, positive predictive value 83.9%, negative predictive value was 82.8%, and ROC-AUC 0.81.

Conclusion  Validation of both tests demonstrated satisfactory accuracy. We recommend the quick test for screening purposes, and the modified original version for a thorough evaluation. The tests are easily implemented as they are easy to understand and very affordable.

Natural Trajectory of Recovery of COVID-19 Associated Olfactory Loss

IMPORTANCE

Prevalence of post-viral olfactory loss has increased dramatically due to the frequency and severity of olfactory dysfunction associated with infection by the SARS-CoV-2 virus.

OBJECTIVE

To determine the trajectory of COVID-19 olfactory loss over a six-month period. A key secondary objective is to assess predictive factors associated with the recovery of olfaction.

DESIGN

Longitudinal repeated-measures study that enrolled from May 5, 2020 to February 2, 2021, with the last date of data collection on June 15, 2021.

SETTING

Barnes-Jewish HealthCare/Washington University School of Medicine facilities (Saint Louis, Missouri, USA).

PARTICIPANTS

Individuals who tested positive for SARS-CoV-2 by real-time polymerase chain reaction on nasopharyngeal swab and indicated olfactory loss on COVID-19 screening questionnaire. Individuals were excluded if they had previously diagnosed history of olfactory loss, neurodegenerative disorders, less than 18 years of age, admitted to hospital service, unable to read, write, and understand English, or lacked computer or internet access.

INTERVENTIONS/EXPOSURES

Watch and wait for spontaneous recovery.

MAIN OUTCOMES AND MEASURES

Participants completed olfactory assessments every 30 days for six months. Each assessment consisted of the University of Pennsylvania Smell Identification Test (UPSIT), an objective "scratch-and-sniff" test, and Clinical Global Impressions (CGI), a subjective Likert rating scale.

RESULTS

The mean age was 41 years old (SD = 16). 39 (80%) were female and 42 (86%) white. At baseline assessment of objective olfaction, 18 (36%) participants had anosmia or severe hyposmia. Subjective, complete recovery at six months was 81% (95% CI 74% to 88%). Likelihood of recovery was associated with age less than 50 years (aHR = 8.1 (95% CI 1.1 to 64.1)) and mild olfactory loss at baseline (UPSIT = 30-33 for males and 31-34 for females) (aHR 6.2 (95% CI 1.2 to 33.0)).

CONCLUSIONS AND RELEVANCE

The trajectory of olfactory recovery among adults with COVID-19 olfactory loss illustrated rapid recovery within 2-3 weeks of infection, and by six months 81% had recovered based on self-report. Age less than 50 years old and mild severity of olfactory loss at baseline were associated with increased likelihood of recovery of olfaction. These findings can be used to inform shared decision-making with patients.

Anosmia (smell failure) and dysgeusia (taste distortion) in COVID-19: it is genetic

The COVID-19 pandemic is a very contagious respiratory illness with has affected millions of individuals worldwide. In addition to the well-known symptoms of any respiratory virus, COVID-19 can present with anosmia (failure to smell) and dysgeusia (distortion of the sense of taste). It appears to be a genetic link to the biological mechanisms underlying COVID-19-related anosmia and dysgeusia. Significant locus in the vicinity of the UGT2A1 and UGT2A2 genes are currently considered as the main culprit of the symptoms. However, more studies are needed to delineate a clear pathophysiology.Communicated by Ramaswamy H. Sarma.

Prevalence of olfactory dysfunction and quality of life in hospitalised patients 1 year after SARS-CoV-2 infection: a cohort study

OBJECTIVES

To determine the long-term prevalence of olfactory and/or gustatory dysfunction (OD±GD), associated risk factors and impact on quality of life (QoL) in previously hospitalised patients with COVID-19 1 year after infection.

DESIGN

A single-centre cohort study.

SETTING

Patients admitted at a large central London hospital with COVID-19 infection between 10 February 2020 and 22 May 2020.

PARTICIPANTS

150 adult subjects with previously confirmed SARS-CoV-2 infection were recruited between 10 December 2020 and 29 January 2021. Participants were predominantly male (102/150, 68.0%); mean age 58.0±15.9 years and 41.2% (56/136) were of black, Asian and minority ethnic backgrounds.

MAIN OUTCOME MEASURES

EQ-5D-5L values and Sino-Nasal Outcome Test-22 (SNOT-22) scores.

RESULTS

Long-term prevalence of OD±GD was 12.8% (19/149) at median time of 264.5 days following SARS-CoV-2 infection onset. Patients with OD±GD had a significantly higher median total SNOT-22 score (46.1; Q1-Q3: 23.0-60.0; 95% CI 23.0 to 60.0) compared with those without (16.0; Q1-Q3: 5.0-30.5; 95% CI 12.0 to 18.0) (p=0.0002), reflecting poorer QoL, particularly psychological well-being (p=0.0004), which was not alleviated with time (p=0.4977). Median EQ-5D-5L value was not significantly different between patients with OD±GD (0.70; Q1-Q3: 0.38-0.83; 95% CI 0.38 to 0.83) and those without (0.83; Q1-Q3: 0.61-0.94; 95% CI 0.75 to 0.89) (p=0.0627). Age, sex, ethnicity, smoking status, highest C reactive protein value, intubation and ventilation, and oxygen supplementation were not found to influence OD±GD (p>0.05).

CONCLUSIONS

12.8% of previously hospitalised patients with COVID-19 in London still report persistent problems with smell or taste up to a year after infection, impacting their QoL. Increased holistic support including psychological therapy and olfactory rehabilitation for affected patients may help to reduce long-term morbidity.

Self-reported olfactory and gustatory dysfunctions in COVID-19 patients: a 1-year follow-up study in Foggia district, Italy

BACKGROUND

From the initial stages of the pandemic in early 2020, COVID-19-related olfactory and gustatory dysfunctions have been widely reported and are emerging as one of the most frequent long-term sequelae of SARS-CoV-2 infection. However, data regarding the long-term recovery of the sense of smell and taste are lacking. This study aimed to characterize the evolution up to one year after the diagnosis of self-reported olfactory and gustatory dysfunctions in COVID-19 cases.

METHODS

Based on the data of the active surveillance platform of the Apulia region, Italy, we selected the residents of Foggia district who were confirmed positive for SARS-CoV-2 from March 1st to June 16th, 2020, and home-quarantined with paucisymptomatic-to-mild clinical presentation. Self-reported olfactory and gustatory dysfunctions were recorded at baseline through a survey of dichotomous questions. The evolution of these symptoms at approximately one year was prospectively assessed via telephone by the validated sino-nasal outcome test 22 (SNOT-22, Italian version).

RESULTS

Among the 1,175 COVID-19 cases notified in the Foggia district during the first epidemic wave, 488 had paucisymptomatic-to-mild clinical presentation. Of these, 41.2% (n = 201, 95% confidence interval [CI] 36.8-45.7%) reported at least one sensory dysfunction. A total of 178 to 201 (88.5%) patients agreed to participate in the follow-up survey. According to the SNOT-22 results, the persistence of a sensory dysfunction was observed in the 29.8% (n = 53, 95% CI 23.2-37.1%) of them. Particularly, loss of smell persisted in 25.8% (n = 46, 95% CI 19.6-32.9%), loss of taste in 21.3% (n = 38, 95% CI 15.6-28.1%), loss of both in 17.4% (n = 31, 95% CI 12.2-23.8%) of participants in the follow-up. The rates of full recovery increased over time: from 59% at 30 days to 71.9% at 90 days for the sense of smell; from 61.3% at 30 days to 74.7% at 90 days for the sense of taste.

CONCLUSIONS

The persistence of COVID-19-related olfactory and gustatory dysfunctions up to 12 months after the disease onset in a noteworthy proportion (approximately 3 out of 10) of patients with paucisymptomatic-to-mild clinical presentation deserves further investigations due to its possible pathophysiological implications and impact on the quality of life.

The Effects of Persistent Olfactory and Gustatory Dysfunctions on Quality of Life in Long-COVID-19 Patients

(1) Background: Persistent olfactory (POD) and gustatory (PGD) dysfunctions are one of the most frequent symptoms of long-Coronavirus Disease 2019 but their effect on the quality of life (QoL) of patients is still largely unexplored. (2) Methods: An online survey was administered to individuals who reported to have had SARS-CoV-2 infection at least 6 months prior with persisting COVID-19 symptoms (using the COVID symptom index), including ratings of POD and PGD, and their physical (PCS) and mental (MCS) components of quality of life were assessed using the standardized short form 12 questionnaire (SF-12). (3) Results: Responses from 431 unique individuals were included in the analyses. The most frequent persistent symptoms were: fatigue (185 cases, 42.9%), olfactory dysfunction (127 cases, 29.5%), gustatory dysfunction (96 cases, 22.3%) and muscle pain (83 cases, 19.3%). Respondents who reported persisting muscle pain, joint pain, fatigue, headache, gastrointestinal disturbances, and dyspnea had significantly worse PCS. Those experiencing persistent fatigue and dyspnea also showed significantly lower MCS. Respondents reporting POD or PGD showed significantly worse QoL, but only pertaining to the MCS. Multiple regressions predicted MCS based on olfactory and marginally on gustatory ratings, but not PCS. Age significantly affected the prediction of PCS but not MCS, and gender and temporal distance from the COVID-19 diagnosis had no effect. (4) Conclusions: POD and PGD are frequent symptoms of the long-COVID-19 syndrome and significantly reduce QoL, specifically in the mental health component. This evidence should stimulate the establishment of appropriate infrastructure to support individuals with persistent CD, while research on effective therapies scales up.

Olfactory Dysfunction in Patients With Coronavirus Disease 2019: A Review

The coronavirus disease 2019 (COVID-19) pandemic is wreaking havoc on public-health and economic systems worldwide. Among the several neurological symptoms of patients with COVID-19 reported in clinical practice, olfactory dysfunction (OD) is the most common. OD occurs as the earliest or the only clinical manifestation in some patients. Increasing research attention has focused on OD, which is listed as one of the main diagnostic symptoms of severe acute respiratory syndrome-coronavirus-2 infection. Multiple clinical and basic-science studies on COVID-19-induced OD are underway to clarify the underlying mechanism of action. In this review, we summarize the clinical characteristics, mechanisms, evaluation methods, prognosis, and treatment options of COVID-19-induced OD. In this way, we hope to improve the understanding of COVID-19-induced OD to aid early identification and precise intervention.

A systematic review of olfactory-related brain structural changes in patients with congenital or acquired anosmia

Brain structural features of healthy individuals are associated with olfactory functions. However, due to the pathophysiological differences, congenital and acquired anosmia may exhibit different structural characteristics. A systematic review was undertaken to compare brain structural features between patients with congenital and acquired anosmia. A systematic search was conducted using PubMed/MEDLINE and Scopus electronic databases to identify eligible reports on anosmia and structural changes and reported according to PRISMA guidelines. Reports were extracted for information on demographics, psychophysical evaluation, and structural changes. Then, the report was systematically reviewed based on various aetiologies of anosmia in relation to (1) olfactory bulb, (2) olfactory sulcus, (3) grey matter (GM), and white matter (WM) changes. Twenty-eight published studies were identified. All studies reported consistent findings with strong associations between olfactory bulb volume and olfactory function across etiologies. However, the association of olfactory function with olfactory sulcus depth was inconsistent. The present study observed morphological variations in GM and WM volume in congenital and acquired anosmia. In acquired anosmia, reduced olfactory function is associated with reduced volumes and thickness involving the gyrus rectus, medial orbitofrontal cortex, anterior cingulate cortex, and cerebellum. These findings contrast to those observed in congenital anosmia, where a reduced olfactory function is associated with a larger volume and higher thickness in parts of the olfactory network, including the piriform cortex, orbitofrontal cortex, and insula. The present review proposes that the structural characteristics in congenital and acquired anosmia are altered differently. The mechanisms behind these changes are likely to be multifactorial and involve the interaction with the environment.

Genetics of congenital olfactory dysfunction: a systematic review of the literature

Olfaction, as one of our 5 senses, plays an important role in our daily lives. It is connected to proper nutrition, social interaction, and protection mechanisms. Disorders affecting this sense consequently also affect the patients' general quality of life. Because the underlying genetics of congenital olfactory disorders (COD) have not been thoroughly investigated yet, this systematic review aimed at providing information on genes that have previously been reported to be mutated in patients suffering from COD. This was achieved by systematically reviewing existing literature on 3 databases, namely PubMed, Ovid Medline, and ISI Web of Science. Genes and the type of disorder, that is, isolated and/or syndromic COD were included in this study, as were the patients' associated abnormal features, which were categorized according to the affected organ(-system). Our research yielded 82 candidate genes/chromosome loci for isolated and/or syndromic COD. Our results revealed that the majority of these are implicated in syndromic COD, a few accounted for syndromic and isolated COD, and the least underly isolated COD. Most commonly, structures of the central nervous system displayed abnormalities. This study is meant to assist clinicians in determining the type of COD and detecting potentially abnormal features in patients with confirmed genetic variations. Future research will hopefully expand this list and thereby further improve our understanding of COD.

Using the Intranasal Route to Administer Drugs to Treat Neurological and Psychiatric Illnesses: Rationale, Successes, and Future Needs

While the intranasal administration of drugs to the brain has been gaining both research attention and regulatory success over the past several years, key fundamental and translational challenges remain to fully leveraging the promise of this drug delivery pathway for improving the treatment of various neurological and psychiatric illnesses. In response, this review highlights the current state of understanding of the nose-to-brain drug delivery pathway and how both biological and clinical barriers to drug transport using the pathway can been addressed, as illustrated by demonstrations of how currently approved intranasal sprays leverage these pathways to enable the design of successful therapies. Moving forward, aiming to better exploit the understanding of this fundamental pathway, we also outline the development of nanoparticle systems that show improvement in delivering approved drugs to the brain and how engineered nanoparticle formulations could aid in breakthroughs in terms of delivering emerging drugs and therapeutics while avoiding systemic adverse effects.

Immune responses in the injured olfactory and gustatory systems: a role in olfactory receptor neuron and taste bud regeneration?

Sensory cells that specialize in transducing olfactory and gustatory stimuli are renewed throughout life and can regenerate after injury unlike their counterparts in the mammalian retina and auditory epithelium. This uncommon capacity for regeneration offers an opportunity to understand mechanisms that promote the recovery of sensory function after taste and smell loss. Immune responses appear to influence degeneration and later regeneration of olfactory sensory neurons and taste receptor cells. Here we review surgical, chemical, and inflammatory injury models and evidence that immune responses promote or deter chemosensory cell regeneration. Macrophage and neutrophil responses to chemosensory receptor injury have been the most widely studied without consensus on their net effects on regeneration. We discuss possible technical and biological reasons for the discrepancy, such as the difference between peripheral and central structures, and suggest directions for progress in understanding immune regulation of chemosensory regeneration. Our mechanistic understanding of immune-chemosensory cell interactions must be expanded before therapies can be developed for recovering the sensation of taste and smell after head injury from traumatic nerve damage and infection. Chemosensory loss leads to decreased quality of life, depression, nutritional challenges, and exposure to environmental dangers highlighting the need for further studies in this area.

Subjective Mouthfeel and Temperature Alterations in COVID-19 Patients Six to Ten Months After Diagnosis

Introduction

The characteristics and impact of mouthfeel, temperature, smell, and taste alterations in patients with COVID-19 at a long term are yet not well known. In this study, these characteristics and their impact on daily life and quality of life (QoL) were assessed, six to ten months after infection, in patients with COVID-19 searching for peer support on Facebook.

Methods

Between December 2020 and January 2021, members of two COVID-19 Facebook groups were invited to complete a questionnaire. Participants were asked to report their perception of mouthfeel, temperature, smell, and taste alterations and their impact.

Results

The questionnaire was completed by 157/216 respondents (73%), with 92% being women. Alterations in mouthfeel, temperature, smell, and taste were reported by respectively 66, 40, 148, and 133 participants. The most frequently reported mouthfeel alterations were "a different feeling" and "dry mouth" in 38 and 30 participants, respectively. Preferences for food temperature were equally changed to "freezing", "cool", "room temperature", "a bit warmer", and "warmer". An impact on daily life and QoL was reported by most patients with alterations in mouthfeel (91% and 79%), temperature (78% and 60%), smell (98% and 93%), and taste (93% and 88%), respectively.

Conclusions

Patients with COVID-19 searching for peer support on Facebook experienced, next to smell and taste alterations, mouthfeel and temperature disturbances, six to ten months after infection. These alterations have an impact on daily life and QoL.

Implications

Health professionals should, next to smell and taste alterations, be aware of mouthfeel and temperature alterations in patients with COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12078-022-09304-y.

A Pilot Study of Self-Rated and Psychophysical Olfactory Dysfunction in Men Living with HIV

Background

Olfactory loss is associated with poor quality of life, malnutrition, and increased risk of depression, yet few studies have examined unawareness of olfactory dysfunction in men living with HIV (MLWH).

Method

MLWH (n = 51) completed olfaction self-ratings, psychophysical odor identification testing, cognitive measures, and questionnaires assessing smell habits, mood, cognitive failures, and quality of life. The sensitivity and specificity of olfactory self-ratings was calculated, and t-tests were used to examine factors contributing to discordance between self-rated and psychophysical olfaction dysfunction.

Results

We found that 33.3% (17 of 51 MLWH) of our sample demonstrated discordance between self-reported and psychophysical olfactory scores. Those unaware of olfaction dysfunction reported using less scented products in daily life but showed no other differences across demographic, clinical, or cognitive indices.

Conclusions

Our results cohere with prior studies of cognitively normal older adults, traumatic brain injury, and Parkinson's disease, which found that olfactory self-ratings may inadequately capture the full range of a person's olfactory status. Our work extends these findings to MLWH, with discordance rates ranging from 35 to 61% for self-rated and psychophysical olfactory dysfunction.

Implications

Given the differing rates of self-rated and psychophysical olfaction in our sample, psychophysical olfactory measures may be useful to consider in the neuropsychological assessment and clinical care of PLWH.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12078-022-09305-x.

Olfaction in the context of obesity and diabetes: Insights from animal models to humans

The olfactory system is at the crossroad between sensory processing and metabolic sensing. In addition to being the center of detection and identification of food odors, it is a sensor for most of the hormones and nutrients responsible for feeding behavior regulation. The consequences of modifications in body homeostasis, nutrient overload and alteration of this brain network in the pathological condition of food-induced obesity and type 2 diabetes are still not elucidated. The aim of this review was first to use both humans and animal studies to report on the current knowledge of the consequences of obesity and type 2 diabetes on odorant threshold and olfactory perception including identification discrimination and memory. We then discuss how olfactory processing can be modified by an alteration of the metabolic homeostasis of the organism and available elements on pharmacological treatments that regulate olfaction. We focus on data within the olfactory system but also on the interactions between the olfactory system and other brain networks impacted by metabolic diseases.

Patients' Perspectives on Qualitative Olfactory Dysfunction: Thematic Analysis of Social Media Posts

Background

The impact of qualitative olfactory disorders is underestimated. Parosmia, the distorted perception of familiar odors, and phantosmia, the experience of odors in the absence of a stimulus, can arise following postinfectious anosmia, and the incidences of both have increased substantially since the outbreak of COVID-19.

Objective

The aims of this study are to explore the symptoms and sequalae of postinfectious olfactory dysfunction syndrome using unstructured and unsolicited threads from social media, and to articulate the perspectives and concerns of patients affected by these debilitating olfactory disorders.

Methods

A thematic analysis and content analysis of posts in the AbScent Parosmia and Phantosmia Support group on Facebook was conducted between June and December 2020.

Results

In this paper, we identify a novel symptom, olfactory perseveration, which is a triggered, identifiable, and usually unpleasant olfactory percept that persists in the absence of an ongoing stimulus. We also observe fluctuations in the intensity and duration of symptoms of parosmia, phantosmia, and olfactory perseveration. In addition, we identify a group of the most common items (coffee, meat, onion, and toothpaste) that trigger distortions; however, people have difficulty describing these distortions, using words associated with disgust and revulsion. The emotional aspect of living with qualitative olfactory dysfunction was evident and highlighted the detrimental impact on mental health.

Conclusions

Qualitative and unsolicited data acquired from social media has provided useful insights into the patient experience of parosmia and phantosmia, which can inform rehabilitation strategies and ongoing research into understanding the molecular triggers associated with parosmic distortions and research into patient benefit.

A Preliminary Investigation of Interspecific Chemosensory Communication of Emotions: Can Humans (Homo sapiens) Recognise Fear- and Non-Fear Body Odour from Horses (Equus ferus caballus)

Simple Summary

Thus far, little attention has been paid to interspecific odour communication of emotions, and no studies have examined whether humans are able to recognise animal emotions from body odour. Thus, the aim of the present study was to address this question. Body odour samples were collected from 16 two-year-old thoroughbred horses in fear and non-fear situations, respectively. The horse odour samples were then assessed by 73 human odour raters. We found that humans, as a group, were able to correctly assign whether horse odour samples were collected under a fear- or a non-fear condition, respectively. An open question remains, which is whether humans could simply distinguish between little versus much sweat and between high intensity versus low intensity or were able to recognise horses’ fear and non-fear emotions. To conclude, the present results indicate that olfaction might contribute to the human recognition of horse emotions. However, these results should be addressed with caution in light of the study’s limitations and only viewed as exploratory for future studies.

Abstract

Mammalian body odour conveys cues about an individual’s emotional state that can be recognised by conspecifics. Thus far, little attention has been paid to interspecific odour communication of emotions, and no studies have examined whether humans are able to recognise animal emotions from body odour. Thus, the aim of the present study was to address this question. Body odour samples were collected from 16 two-year-old thoroughbred horses in fear and non-fear situations, respectively. The horse odour samples were then assessed by 73 human odour raters. We found that humans, as a group, were able to correctly assign whether horse odour samples were collected under a fear- or a non-fear condition, respectively. Furthermore, they perceived the body odour of horses collected under the fear condition as more intense, compared with the non-fear condition. An open question remains, which is whether humans could simply distinguish between little versus much sweat and between high intensity versus low intensity or were able to recognise horses’ fear and non-fear emotions. These results appear to fit the notion that the ability to recognise emotions in other species may present an advantage to both the sender and the receiver of emotional cues, particularly in the interaction between humans and domesticated animals. To conclude, the present results indicate that olfaction might contribute to the human recognition of horse emotions. However, these results should be addressed with caution in light of the study’s limitations and only viewed as exploratory for future studies.

Reliability and validity of a brief version of the Questionnaire of Olfactory Disorders (brief QOD) in patients with olfactory dysfunction

BACKGROUND

The aim of this study was to determine the reliability and validity of the brief version of Questionnaire of Olfactory Disorders (brief QOD).

METHODS

A total of 372 patients participated in this study. Olfactory function was examined using the Sniffin' Sticks test. The brief version of QOD, including 4 items concerning parosmia (QOD-P), 7 items concerning quality of life (QOD-QOL), and 3 visual analog scales to rate disease burden, awareness of the disorder and issues related to professional life (QOD-VAS), was used to assess subjective information on olfactory dysfunction. We evaluated the split-half reliability, internal consistency and validity of the brief QOD.

RESULTS

The split-half reliability was 0.60 (QOD-P), 0.87 (QOD-QOL), and 0.66 (QOD-VAS), respectively. The Cronbach's α coefficient was 0.63 (QOD-P), 0.87 (QOD-QOL), and 0.71 (QOD-VAS), respectively. Olfactory function was found to be associated with QOD-P, QOD-QOL and QOD-VAS.

CONCLUSIONS

The brief QOD is a suitable scale for the assessment of subjective severity of olfactory dysfunction for purposes such as treatment counseling, disability assessment, treatment control, and research in patients with olfactory disorder.

Otolaryngic sensory loss as a measure of frailty among older US adults

BACKGROUND

Frailty is a syndrome characterized by reduced physiologic reserve and increased vulnerability to poor health outcomes. Disruption of sensorineural function appears to serve as a novel biomarker of frailty. Using population-level data, we sought to characterize the association between otolaryngic sensory dysfunction and frailty.

METHODS

A cross-sectional analysis of the 2011-2012 US National Health and Nutrition Examination Survey was performed on adults ≥40 years of age (n = 2138). Participants were grouped by subjective gustatory dysfunction (sGD), olfactory dysfunction (sOD), hearing loss (sHL), and measured hearing loss (mHL) with pure tone averages (PTAs). Frailty was operationalized using a continuous 36-item frailty index (FI) scored from 0 to 1, stratified in 4 categories ("non-frail," "vulnerable," "frail," or "most frail").

RESULTS

All sensory loss groups had significantly higher FI scores than those without sensory loss (sGD = 0.15; sOD = 0.14; sHL = 0.15; low-frequency mHL = 0.16; high-frequency mHL = 0.14 vs control = 0.11; p < 0.007 for all). "Vulnerable" individuals had increased odds of sOD (adjusted odds ratio [aOR], 1.45; 95% confidence interval [CI], 1.05-2.00), whereas "frail" individuals had increased odds of sOD (aOR, 1.85; 95% CI, 1.26-2.71) and low-frequency mHL (aOR, 4.01; 95% CI, 1.27-12.63). The "most frail" individuals had increased odds of sHL (aOR, 11.72; 95% CI, 2.88-47.66) and high-frequency mHL (aOR 5.10; 95% CI, 1.72-15.12). PTAs were linearly associated with FI (low: β = 10.15; 95% CI, 1.78-18.51; high: β = 19.85; 95% CI, 5.19-34.53).

CONCLUSION

Otolaryngic sensory loss is associated with increased frailty. Independent association of frailty with measures of olfaction and hearing suggests that olfactory and hearing assessments may help identify at-risk individuals with modifiable risk factors.

Clinical Features of Parosmia Associated With COVID-19 Infection

Objective

To characterize the clinical features, risk factors, symptom time‐course, and quality of life implications for parosmia among coronavirus disease (COVID)‐related olfactory dysfunction patients.

Methods

Individuals with olfactory dysfunction associated with laboratory‐confirmed or clinically suspected COVID‐19 infection were recruited from otolaryngology and primary care practices over a period from August 2020 to March 2021. Participants completed olfactory dysfunction and quality of life surveys.

Results

A total of 148 (64.1%) of 231 respondents reported parosmia at some point. Parosmia developed within 1 week of any COVID‐19 symptom onset in 25.4% of respondents, but more than 1 month after symptom onset in 43.4% of respondents. Parosmia was associated with significantly better quantitative olfactory scores on Brief Smell Identification Test (8.7 vs. 7.5, P = .006), but demonstrated worse quality of life scores, including modified brief Questionnaire of Olfactory Dysfunction—Negative Statements and Sino‐Nasal Outcome Test‐22 scores (12.1 vs. 8.5, P < .001; 26.2 vs. 23.2, P = .113). Participants who developed parosmia at any point were significantly younger and less likely to have history of chronic sinusitis than those who did not develop parosmia (40.2 vs. 44.9 years, P = .007; 7.2% vs. 0.7%, P = .006).

Conclusion

COVID‐19‐associated olfactory dysfunction is frequently linked with development of parosmia, which often presents either at onset of smell loss or in a delayed fashion. Despite better quantitative olfactory scores, respondents with parosmia report decreased quality of life. A majority of respondents with persistent parosmia have sought treatment.

Level of Evidence

3 Laryngoscope, 132:633–639, 2022

Prevalence of Persistent Olfactory Disorders in Patients With COVID-19: A Psychophysical Case-Control Study With 1-Year Follow-up

The purpose of this multicenter case-control study was to evaluate a group of patients at least 1 year after coronavirus disease 2019 (COVID-19) with Sniffin' Sticks tests and to compare the results with a control population to quantify the potential bias introduced by the underlying prevalence of olfactory dysfunction (OD) in the general population. The study included 170 cases and 170 controls. In the COVID-19 group, 26.5% of cases had OD (anosmia in 4.7%, hyposmia in 21.8%) versus 3.5% in the control group (6 cases of hyposmia). The TDI score (threshold, discrimination, and identification) in the COVID-19 group was significantly lower than in the control group (32.5 [interquartile range, 29-36.5] vs 36.75 [34-39.5], P < .001). The prevalence of OD was significantly higher in the COVID-19 group, confirming that this result is not due to the underlying prevalence of OD in the general population.

Automated olfactory bulb segmentation on high resolutional T2-weighted MRI

The neuroimage analysis community has neglected the automated segmentation of the olfactory bulb (OB) despite its crucial role in olfactory function. The lack of an automatic processing method for the OB can be explained by its challenging properties (small size, location, and poor visibility on traditional MRI scans). Nonetheless, recent advances in MRI acquisition techniques and resolution have allowed raters to generate more reliable manual annotations. Furthermore, the high accuracy of deep learning methods for solving semantic segmentation problems provides us with an option to reliably assess even small structures. In this work, we introduce a novel, fast, and fully automated deep learning pipeline to accurately segment OB tissue on sub-millimeter T2-weighted (T2w) whole-brain MR images. To this end, we designed a three-stage pipeline: (1) Localization of a region containing both OBs using FastSurferCNN, (2) Segmentation of OB tissue within the localized region through four independent AttFastSurferCNN - a novel deep learning architecture with a self-attention mechanism to improve modeling of contextual information, and (3) Ensemble of the predicted label maps. For this work, both OBs were manually annotated in a total of 620 T2w images for training (n=357) and testing. The OB pipeline exhibits high performance in terms of boundary delineation, OB localization, and volume estimation across a wide range of ages in 203 participants of the Rhineland Study (Dice Score (Dice): 0.852, Volume Similarity (VS): 0.910, and Average Hausdorff Distance (AVD): 0.215 mm). Moreover, it also generalizes to scans of an independent dataset never encountered during training, the Human Connectome Project (HCP), with different acquisition parameters and demographics, evaluated in 30 cases at the native 0.7 mm HCP resolution (Dice: 0.738, VS: 0.790, and AVD: 0.340 mm), and the default 0.8 mm pipeline resolution (Dice: 0.782, VS: 0.858, and AVD: 0.268 mm). We extensively validated our pipeline not only with respect to segmentation accuracy but also to known OB volume effects, where it can sensitively replicate age effects (β=-0.232, p<.01). Furthermore, our method can analyze a 3D volume in less than a minute (GPU) in an end-to-end fashion, providing a validated, efficient, and scalable solution for automatically assessing OB volumes.

Differences in Correlation between Subjective and Measured Olfactory and Gustatory Dysfunctions after Initial Ear, Nose and Throat Evaluation

Introduction  Subjective chemosensory function can differ from measured function. Previous studies on olfactory assessment have found a positive correlation between subjective and measured scores. However, information on gustatory correlation between measured and subjective functions is sparse in patients who have undergone an initial ear, nose and throat (ENT) evaluation.

Objectives  To evaluate the correlation between subjective and measured olfactory and gustatory dysfunctions in a population complaining of taste and/or smell dysfunction after an initial ENT evaluation without chemosensory testing. Furthermore, we aimed to assess the need for chemosensory testing depending on the type of subjective chemosensory dysfunction.

Methods  A case series in which subjective chemosensory function was assessed through a questionnaire and measured chemosensory function was assessed by validated clinical tests.

Results  In total, 602 patients with complaints of olfactory and/or gustatory dysfunction were included. We found that 50% of the patients with normal gustatory function and an olfactory impairment classified their olfactory impairment as a subjective taste disorder. Furthermore, 98% of the patients who rated their olfactory function as absent did have a measurable olfactory impairment, but only 64% were anosmic.

Conclusion  Subjective gustatory dysfunction was poorly correlated with measured gustatory dysfunction, and was often found to reflect olfactory dysfunction. Contrarily, subjective olfactory dysfunction was positively correlated with measurable olfactory dysfunction. Although subjective anosmia was a strong indicator of measured anosmia or hyposmia, the existence of remaining olfactory function was frequently found in these patients. Validated chemosensory testing should be performed in patients with perceived olfactory or gustatory deficits, as this could help ensure increased diagnostic precision and a relevant treatment.

Olfactory-Specific Quality of Life Outcomes after Endoscopic Endonasal Surgery of the Sella

Objective

To assess olfactory outcomes as measured by an olfactory-specific quality of life (QOL) questionnaire in patients undergoing EESBS for sellar lesions.

Design

Retrospective case series.

Setting

Tertiary academic medical center.

Participants

In total, 36 patients undergoing EESBS for lesions limited to the sella were evaluated.

Main Outcome Measures

The following were performed before and three months after surgery: 22-Item Sinonasal Outcomes Test (SNOT-22), University of Pennsylvania Smell Identification Test (UPSIT), and the Assessment of Self-reported Olfactory Functioning (ASOF), which has three domains: subjective olfactory capability scale (SOC), smell-related problems (SRP), and olfactory-related quality of life (ORQ).

Results

Median age at surgery was 52.5 years, with a median tumor size of 1.8 cm (range: 0.2 to 3.9 cm). Pre- and postoperative median scores were 35 [34, 36.2] and 34.5 [32, 36] for UPSIT, 21 [7.5, 33.5] and 21.5 [6.8, 35.7] for SNOT-22, 10 [9, 10] and 9 [8, 10] for ASOF-SOC, 5 [4.8, 5] and 4.5 [4, 5] for ASOF-SRP, and 5 [5, 5] and 5 [4.5, 5] for ASOF-ORQ. There was no significant change in the two of the three domains of the ASOF. Correlation between ASOF and UPSIT scores were weak. Older age and larger tumor size were associated with worsened olfaction after surgery.

Conclusions

Patients did not experience significant changes in olfactory-specific QOL three months after EESBS, as measured by two domains of the ASOF. The ASOF may serve as a useful adjunctive tool for assessing olfaction after surgery. The lack of correlation between UPSIT and ASOF suggests the need for more research in subjective olfactory-related quality of life after surgery.

Taste, smell and mouthfeel disturbances in patients with gastrointestinal stromal tumors treated with tyrosine-kinase inhibitors

CONTEXT

Taste, smell, and mouthfeel disturbances are underrated and underreported, but important side effects of anti-cancer medication. These symptoms are associated with a lower quality of life (QoL). The prevalence and the impact of taste, smell, and mouthfeel disturbances on daily life in patients with a gastrointestinal stromal tumor (GIST) are largely unknown.

OBJECTIVES

This exploratory study assessed the prevalence and type of taste, smell, and mouthfeel disturbances and their impact on daily life and QoL in patients with a GIST treated with a tyrosine-kinase inhibitor (TKI).

METHODS

Patients currently treated with TKIs for GIST completed a standardized questionnaire. The questionnaire addressed changes in taste, smell, and mouthfeel and, if changes occurred, impact on daily life and QoL. Statistics are descriptive.

RESULTS

A total of 65 GIST patients on TKI treatment completed the questionnaire. Of these patients, 79%, 12%, and 9% currently used imatinib, sunitinib, and regorafenib respectively. Taste, smell, and mouthfeel disturbances were reported by 25 (38%), 15 (23%), and 36 (55%) patients respectively. Salty and sweet tastes were mostly affected, respectively in 14 and 13 patients. A dry mouth was experienced by 29 (45%) patients. Taste disturbances were more often reported to have impact on daily life and QoL (80% and 60%) than smell (47% and 31%) and mouthfeel disturbances (47% and 30%).

CONCLUSION

Taste, smell, and mouthfeel disturbances are frequent side effects of TKIs in GIST patients. Daily life and QoL are affected in a considerable number of those patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NL7827 (2019-06-25).

Radiofrequency ablation turbinoplasty improves the sense of smell in pediatric patients: A prospective study

INTRODUCTION

The olfactory sense is of paramount importance for the adequate development of a child. Olfactory loss in children might have different origins. One of the most common is conductive, when nasal obstruction prevents odorants from reaching the olfactory epithelium. Rhinitis and turbinate enlargement have been proven to diminish the sense of smell in pediatric patients. A common treatment for resistant rhinitis in these patients is turbinate radiofrequency ablation (TRA). However, despite an increasing research effort in this field, there are no studies instrumentally assessing olfaction in children undergoing turbinate surgery to date. This study was designed with the aim of assessing changes in olfaction through validated instrumental tools in pediatric patients undergoing TRA for the first time.

METHODS

A prospective uncontrolled intervention clinical trial design was conducted. Two cohorts of children ranging 4-15 years old were consecutively selected from a third level referral Hospital and subjected to the universal sniff test (U-Sniff), alcohol sniff test (AST), and sniffin sticks threshold test (SST) before and 1, 3 and 6 months after surgery. Cohort A consisted of children solely undergoing TRA. Cohort B consisted of children on whom adenoidectomy and TRA had been performed. Additionally, a cohort of Spanish healthy controls, paired by sex and age, were asked to perform the U-Sniff.

RESULTS

A total of 81 participants with a mean age of 10.31 ± 2.56 years were included. Fifty-three patients underwent TRA exclusively and 28 were subjected to associated adenoidectomy. Despite a tendency toward improvement in the U-sniff scores, there were no statistically significant differences after surgery. However, statistically significant differences were obtained for threshold tasks measured with SST and AST, revealing differences at 1, 3 and 6 months after surgery compared to preoperative scores.

CONCLUSIONS

In summary, this research demonstrated adequate levels in the sense of smell regarding identification tasks, but decreased olfactory threshold scores in pediatric patients suffering from TE. TRA, alone or with adenoidectomy, improved smell threshold scores, but had no significant effect on identification tasks.

What about using sniffin' sticks 12 items test to screen post-COVID-19 olfactory disorders?

Background

Post-COVID-19 Olfactory impairment has a negative impact on quality of life. The Sniffin Sticks test 12 items (SST-12) can be used in quick olfactory disorders screening. Its evaluation in a post-covid-19 situation was the main objective of this work.

Methods

All patient impaired with a post-COVID olfactory loss were included while consulting to the ENT department. The clinical examination included an olfaction recovery self-assessment (VAS), a nasofibroscopy, a quality of life (QoL) assessment, the complete Sniffin’ Sticks Test (SST), and the SST-12.

Results

Among the 54 patients included, 92% (n = 50) were correctly screened as olfactory impaired by SST-12. We report excellent correlations between SST-12 and SST (rho ₍₅₂₎ = 0.98, p < 0.001), QoL(rho₍₅₂₎ = 0.33 p = 0.016), or VAS (rho₍₅₂₎ = 0.49, p < 0.001) assessments.

Conclusions

SST-12 is a quick and reliable tool to screen large-scale population of post-COVID-19 olfactory impaired patients and could be used in a general daily clinical practice.

Sensory compensation beliefs among blind and sighted individuals

The process of neural and behavioral reorganization following sensory loss is known as sensory compensation. Typically, it is believed that sensory loss is followed by increased acuity of the intact modalities. Indeed, many studies compared blind and sighted individuals' sensitivity of the intact sensory modalities. Yet, it remains poorly understood whether sensory compensation is reflected in the lay beliefs of those, whom it concerns. We examined whether blind and sighted individuals believe that their lack of vision is compensated by increased sensitivity of the intact senses. Study 1 (n = 63) aimed to compare the ratings of sensory sensitivity made by blind and sighted people. Participants rated the sensory sensitivity of a blind population in four modalities (i.e., olfaction, audition, gustation, touch) and compared it to the sensory sensitivity of a sighted population. In Study 2 (n = 191) participants rated their own sensory sensitivity in four modalities. Each participant referred to (1) people of the same sensory status and (2) people of the opposite sensory status. The level of global self-esteem was controlled to verify self-enhancing nature of these beliefs. The results of both studies showed that the beliefs about sensory compensation are shared by blind and sighted participants on group and on individual levels. The self-enhancement underpinning of these beliefs was most pronounced in gustatory sensitivity assessment. Psychological and medical consequences of sensory compensation beliefs are discussed.

Development of quality of life assessment questionnaire associated with osmophobia in people with migraine

BACKGROUND

It is important to implement disease-specific precautions to develop quality of life in migraine. The effect of osmophobia, which is one of the specific symptoms of migraine that might help to differentiate migraine from other headache disorders, on quality of life is unknown. The aim of the present study was to develop a practicable and reliable scale that assesses the effect of osmophobia on quality of life in migraine.

METHODS

This cross-sectional study was carried out with 163 patients with migraine and 110 healthy individuals for control group. The scale items were constructed based on after literature review, expert opinions, and preliminary trial stage. A semi-structured interview was conducted with the patients by the Neurologist to evaluate the presence of osmophobia retrospectively. Migraine osmophobia-related quality of life assessment (MORA) consisted of 6 items including personal care, eating or cooking, house cleaning, close relationship, social life and traveling.

RESULTS

The Cronbach's α coefficient was 0.86; and the Guttman split-half coefficient was 0.83. Receiver operating characteristic analysis showed an area under the curve of 0.943 (95%) confidence interval [CI] = 0.902-0.984), a cut off score of > 9.5, a sensitivity of 91.6%, a specificity of 85.7%. Mean scores of the MORA differed between people with migraine (with and without osmophobia) and healthy controls (<0.001).

CONCLUSION

MORA is a valid and reliable self-report questionnaire that assesses the effect of osmophobia on quality of life in migraine. This questionnaire appears to be practicable diagnostic instrument in clinical practice and research.

The Link between Attachment Style and Self-Reported Olfactory Ability: A Preliminary Investigation

Individuals in healthy romantic relationships gain significant benefits to their psychological wellbeing and physiological health. Notably, the majority of relationship research has focused on how adult attachment influences these relationship outcomes while the role of olfaction remains an emerging research focus. The aim of the current study was to bring together these seemingly unrelated factors–attachment and olfaction–in an online quasi-experimental design. The participants were 401 undergraduate students, predominantly females, ranging in age from 17 to 70 years. Participants completed a battery of questionnaires that evaluated their attachment tendencies, olfactory ability and experiences in romantic relationships. Results indicated that attachment insecurity, across both attachment anxiety and avoidance, was associated with decreased olfactory functioning for females. These findings provide preliminary evidence that olfaction is related to romantic relationship maintenance and suggests that body odors could be fundamental for evoking the attachment system. These findings also elicit enticing new avenues of research which can assist psychologists to provide targeted treatments to individuals with olfactory deficits and insecure attachment tendencies.

A study of depression, partnership and sexual satisfaction in patients with post-traumatic olfactory disorders

Post-traumatic olfactory dysfunction (PTOD) is associated with a significant decrease in quality of life. The present study aimed to explore whether PTOD is associated with depression and changes in sexuality. There were two groups in this case-control study. The patient group consisted of patients with PTOD (n = 55), and the control group comprised healthy individuals without the olfactory disorder (n = 115). Olfactory function, depression, partnership, and sexual satisfaction were assessed using the Iranian version of the Sniffin' Sticks test (Ir-SST), Beck Depression Inventory (BDI), Enrich Couple Scale (ECS) and Sexual Satisfaction Scale for Women (SSSW). The BDI scores were higher in the patient group than in the control group (p < 0.001). The SSSW score was lower in the patient group than in controls (p < 0.01), although the ECS score was not significantly different between patients and controls. Also, there was no significant difference in the severity of trauma between marital satisfaction and sexual satisfaction. However, the analysis showed a statistically significant difference in depression scores in connection with the head trauma severity. In the PTOD group, depression was increased and sexual satisfaction declined. Understanding the association of olfactory dysfunction with depression and sexuality allows patients and doctors to deal with less notable consequences of this disorder.

Odorant metabolism of the olfactory cleft mucus in idiopathic olfactory impairment patients and healthy volunteers

BACKGROUND

It remains unclear whether the metabolic activity of nasal mucus in the olfactory and respiratory areas is different. Moreover, age- and olfaction-related changes may affect metabolism.

METHODS

Hexanal, octanal, and 2-methylbutanal were selected for in vitro metabolism analysis and compared between the olfactory cleft and respiratory mucus of participants < 50-year-old with normal olfaction using gas chromatography mass spectrometry. The metabolic activity of hexanal in the olfactory cleft mucus was further compared between three groups, (1) normal olfaction, age < 50 years old, (2) normal olfaction, age ≥50 years old, and (3) idiopathic olfactory impairment. To characterize the enzyme(s) responsible for aldehyde reduction, we also tested if epalr22897estat and 3,5-dichlorosalicylic acid, types of reductase inhibitors, affect metabolism.

RESULTS

Conversion of aldehydes to their corresponding alcohols was observed in the olfactory cleft and respiratory mucus. The metabolic production of hexanol, octanol, and 2-methybutanol was significantly higher in the olfactory cleft mucus than in the respiratory mucus (p < 0.01). The metabolic conversion of hexanal to hexanol in the mucus of the idiopathic olfactory impairment group was significantly lower than that in the age-matched normal olfaction group. Excluding the nicotinamide adenine dinucleotide phosphate (NADPH) regenerating system from the reaction mixture inhibited metabolism. The addition of either epalr22897estat or 3,5-dichlorosalicylic acid did not inhibit this metabolic conversion.

CONCLUSIONS

The enzymatic metabolism of odorants in the olfactory cleft mucus is markedly higher than in the respiratory mucus and decreases in patients with idiopathic olfactory impairment.

Olfactory Outcomes with Dupilumab in Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

Loss of smell (LoS) is one of the most troublesome and difficult-to-treat symptoms of severe chronic rhinosinusitis with nasal polyps (CRSwNP).

OBJECTIVE

To assess the impact of dupilumab on sense of smell in severe CRSwNP.

METHODS

In the randomized SINUS-24 and SINUS-52 studies, adults with severe CRSwNP received dupilumab 300 mg subcutaneously or matching placebo every 2 weeks for 24 or 52 weeks, respectively. Smell was assessed using daily patient-reported LoS score (0-3) and University of Pennsylvania Smell Identification Test (UPSIT; 0-40). Data from the 2 studies were pooled through week 24. Relationships between patient phenotypes and smell outcomes were also assessed.

RESULTS

We randomized 724 patients (286 placebo, 438 dupilumab); mean CRSwNP duration was 11 years; 63% had prior sinonasal surgery. Mean baseline LoS was 2.74. Dupilumab produced rapid improvement in LoS, evident by day 3, which improved progressively throughout the study periods (least squares mean difference vs placebo -0.07 [95% CI -0.12 to -0.02]; nominal P < .05 at day 3, and -1.04 [-1.17 to -0.91]; P < .0001 at week 24). Dupilumab improved mean UPSIT by 10.54 (least squares mean difference vs placebo 10.57 [9.40-11.74]; P < .0001) at week 24 from baseline (score 13.90). Improvements were unaffected by CRSwNP duration, prior sinonasal surgery, or comorbid asthma and/or nonsteroidal anti-inflammatory drug-exacerbated respiratory disease. Baseline olfaction scores correlated with all measured local and systemic type 2 inflammatory markers except serum total immunoglobulin E.

CONCLUSIONS

Dupilumab produced rapid and sustained improvement in sense of smell, alleviating a cardinal symptom of severe CRSwNP.

Olfactory hallucinations in a population-based sample

Olfactory hallucinations referring to olfactory perceptions in the absence of chemical stimuli, occur in non-clinical and clinical populations. Few studies have investigated their prevalence in the general population and little is known about factors triggering and maintaining them such as substance use, severe life events, and mood. We analyzed self-report data from 2500 community dwelling Norwegians, aged 18-96 years, for occurrence of olfactory hallucinations and co-occurring hallucinations in other modalities (auditory, visual, tactile). Analyses included age, sex, self-reported symptoms of depression and anxiety, mental health status, and experience of severe life-events. The results show that 4.2% (95% CI 3.5-5.1%) reported having experienced olfactory hallucinations, and 56% of individuals experiencing olfactory hallucinations also reported these in combination with hallucinations in other modalities. Prevalence varied significantly in terms of age and sex, in that olfactory hallucinations were most frequently reported by young individuals and females. Self-reported symptoms of anxiety and experience of stressful life events were significantly associated with olfactory hallucinations, suggesting that experiencing olfactory hallucinations may negatively affect functioning and may increase the likelihood of developing psychopathology. Findings underline the need to continue to examine olfactory hallucinations albeit with a more comprehensive assessment in order to increase knowledge on this experience.

Altered smell and taste: Anosmia, parosmia and the impact of long Covid-19

Background

Qualitative olfactory (smell) dysfunctions are a common side effect of post-viral illness and known to impact quality of life and health status. Evidence is emerging that taste and smell loss are common symptoms of Covid-19 that may emerge and persist long after initial infection. The aim of the present study was to document the impact of post Covid-19 alterations to taste and smell.

Methods

We conducted exploratory thematic analysis of user-generated text from 9000 users of the AbScent Covid-19 Smell and Taste Loss moderated Facebook support group from March 24 to 30th September 2020.

Results

Participants reported difficulty explaining and managing an altered sense of taste and smell; a lack of interpersonal and professional explanation or support; altered eating; appetite loss, weight change; loss of pleasure in food, eating and social engagement; altered intimacy and an altered relationship to self and others.

Conclusions

Our findings suggest altered taste and smell with Covid-19 may lead to severe disruption to daily living that impacts on psychological well-being, physical health, relationships and sense of self. More specifically, participants reported impacts that related to reduced desire and ability to eat and prepare food; weight gain, weight loss and nutritional insufficiency; emotional wellbeing; professional practice; intimacy and social bonding; and the disruption of people’s sense of reality and themselves. Our findings should inform further research and suggest areas for the training, assessment and treatment practices of health care professionals working with long Covid.

Development of a questionnaire to investigate socio-cultural differences in the perception of smell, taste and flavour

Objectives

Clinical experience and daily life indicate that the importance of smell, taste and flavour is variable among individuals. Therefore, the aim of this research was to develop a questionnaire to investigate the importance attributed to smell, taste and flavour and socio-cultural differences among individuals.

Methods

Cross-cultural adaptation of the questionnaire was executed by two professional translators and one bilingual investigator and pre-tested on a pilot group of 25 subjects with normal smell and taste abilities. The final version of the questionnaire was sent by e-mail to 850 healthy subjects. The Google form consisted of three parts: "The importance of olfaction" developed by Croy et al. in 2010, "The importance of taste and flavour" developed by our team and a section to collect demographic data. The questions were classified into "association", "application", "consequence" and "aggravation". Statistical differences were assessed using t-test with p ≤ 0.05. Correlations were calculated using Spearman's test. Internal consistency was assessed using the Cronbach's Alpha, while test-retest reliability was analysed by calculating the Intraclass Correlation Coefficients (ICC2k).

Results

The questionnaire received a non-response rate of 10.7%. Calculation of Cronbach's alpha showed good internal reliability (a = 0.87). Test-retest evaluation was satisfactory for all subscales, with an overall ICC2k = 0.84 (CI 0.79-0.89). Statistical analysis showed that smell, taste and flavour appeared to be more important for women when compared to men (p < 0.001). No statistical differences were seen between individuals with various educational background (p > 0.05), and the importance of smell (r = 0.16; p < 0.01), taste and flavour (r = 0.08; p < 0.05) did not decline with age.

Conclusions

The development of this original test provides an overview into the importance of smell, taste and flavour among individuals. Although further research is needed, it can help in the evaluation and investigation of aspects that influence people to seek medical attention in the presence of sensory alterations.

Age-Related Olfactory Decline Is Associated With Levels of Exercise and Non-exercise Physical Activities

Objective: This cross-sectional study evaluates the impact of active or non-active lifestyle in terms of physical, cognitive and social activity on the olfactory function in Elderly Subjects (ES) and aims at looking for a correlation between the time devoted to life activities and the score obtained during the olfactory tests by each individual.

Methods: One hundred and twenty-two elderly volunteers were recruited in Sardinia (Italy) and divided into active ES (n = 60; 17 men, 43 women; age 67.8 ± 1.12 years) and inactive ES (n = 62; 21 men, 41 women, age 71.1 ± 1.14 years) based on their daily physical activities. The olfactory function was evaluated using the “Sniffin’s Sticks” battery test, while the assessment of daily activities was made by means of personal interviews.

Results: A significant effect of active or inactive lifestyle was found on the olfactory function of ES (F_(1,120) > 10.16; p < 0.005). A positive correlation was found between the olfactory scores and the number of hours per week dedicated to physical activities (Pearson’s r > 0.32, p ≤ 0.014) in both active and inactive ES.

Conclusions: High levels of exercise and non-exercise physical activity are strongly associated with the olfactory function and, consequently, with the quality of life of the elderly. Given the limited physical exercise of elderly people, they can benefit from a more active lifestyle by increasing non-exercise physical activities.

Loss of smell in patients with traumatic brain injury is associated with neuropsychiatric behavioral alterations

OBJECTIVE

We sought to identify and correlate the severity of traumatic brain injuries (TBIs) associated with olfactory dysfunction with cognitive and behavioral profiles.

PARTICIPANTS AND SETTING

Patients with TBI undergoing treatment in a specialized neuro-rehabilitation hospital.

DESIGN

Prospective study.

MAIN MEASURES

Glasgow Coma Scale (GCS) at the time of injury and during posttraumatic amnesia. Motor functions were assessed with the Functional Instrument Measure and Disability Rating Scales. The Wechsler Adult Intelligence test was used for neuropsychologic assessment and the Neuropsychiatric Inventory was used to assess behavioral changes. The Barcelona Smell Test-24 was used to study subjective smell loss.

RESULTS

A total of 111 patients with TBI were enrolled (33 females; mean age 32.86 years); 38.73% exhibited smell loss. Patients with no olfactory impairment (OI) had worse TBIs than those with OI (GCS scores 5.65 and 7.74, respectively); no significant differences in cognitive behaviors, such as attention memory, visuoperception, and visuoconstruction, were observed. However, patients with TBI and olfactory dysfunction showed statistically significant alterations in neuropsychiatric behavioral performances such as feeding when compared with patients with TBI without smell loss.

CONCLUSION

Olfactory dysfunction in patients with a TBI correlates with altered neuropsychiatric behavioral performances such as feeding, sleeping, and motor behavior.