Olfactory Identification Research Articles

The Neuroanatomic Correlates of Olfactory Identification Impairment in Healthy Older Adults and in Persons with Mild Cognitive Impairment.

Olfactory identification (OI) impairment appears early in the course of Alzheimer's disease dementia (AD), prior to detectable cognitive impairment. However, the neuroanatomical correlates of impaired OI in cognitively normal older adults (CN) and persons with mild cognitive impairment (MCI) are not fully understood. We examined the neuroanatomic correlates of OI impairment in older adults from the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS). Our sample included 1,600 older adults without dementia who completed clinical assessment and structural brain imaging from 2011 to 2013. We characterized OI impairment using the 12-item Sniffin' Sticks odor identification test (score ≤6). We used voxel-based morphometry (VBM) and region of interest (ROI) analyses to examine the neuroanatomic correlates of impaired OI in CN and MCI, after adjusting for potential confounders. Analyses were also separately stratified by race and sex. In CN, OI impairment was associated with smaller amygdala gray matter (GM) volume (p < 0.05). In MCI, OI impairment was associated with smaller GM volumes of the olfactory cortex, amygdala, entorhinal cortex, hippocampus, and insula (ps < 0.05). Differential associations were observed by sex in MCI; OI impairment was associated with lower insular GM volumes among men but not among women (p-interaction = 0.04). There were no meaningful interactions by race. The brain regions associated with OI impairment in individuals without dementia are specifically those regions known to be the primary targets of AD pathogenic processes. These findings highlight the potential utility of olfactory assessment in the identification and stratification of older adults at risk for AD.

Olfactory dysfunction is associated with mild cognitive impairment in community-dwelling older adults.

BackgroundOlfactory impairment is aging related and is associated with cognitive decline in older adults. However, it remains unclear if an olfactory impairment is associated with mild cognitive impairment (MCI) and the degree of impairment in the MCI subtypes.Materials and methodsIn a cohort of community-living older adults aged 60 years and above, 670 participants were recruited from the Community Health and Intergenerational (CHI) Study. Olfactory function was assessed using a locally developed nine-item smell test in association with neurocognitive assessments. Analysis of covariance (ANCOVA) was used to examine the association of smell identification score and clinical cognitive status while considering demographic, clinical, and neuropsychological factors with Bonferroni correction for group comparisons.ResultsAge-related smell detection between normal aging (NA) and MCI participants had no significant difference. The overall mean smell identification score in older adults was negatively correlated with age. The mean smell identification score of MCI participants was also not significantly different as compared with NA, but an amnestic MCI multiple domain (aMCI_MD) subgroup had significantly lower (impaired) mean smell identification scores compared with the NA and MCI single domain (amnestic and non-amnestic) group.ConclusionThis study demonstrated that olfactory identification impairment is a comorbidity in older adults with amnestic MCI (aMCI) and is a potential marker associated with an early stage of a neurocognitive disorder. The smell test could act as a screening tool to help in the early detection of smell impairment for heterogeneous syndromes of MCI among community-dwelling older adults. Clinicians and researchers could benefit from utilizing the locally developed smell test to screen their patients or research participants before the initiation of an appropriate health intervention or in a clinical trial.

Olfactory cleft mucus galectin-10 predicts olfactory loss in chronic rhinosinusitis

BackgroundEosinophils have been reported to be involved in the pathogenesis of olfactory fluctuation in chronic rhinosinusitis (CRS). Galectin-10 is more frequently associated with type 2 inflammation and potentially a sign of intense eosinophil activation. ObjectiveTo explore olfactory cleft mucus and olfactory mucosa galectin-10 level and its association with olfactory dysfunction (OD) in CRS. MethodsWe prospectively enrolled 50 patients with CRS and 15 healthy controls. Olfactory cleft mucus and superior turbinate biopsy specimens were collected to analyze galectin-10 levels and quantify tissue eosinophils. Psychophysical olfactory testing, olfactory cleft endoscopy scale, and olfactory cleft computed tomography scores were obtained. The predictability of galectin-10 levels for OD in patients with CRS was analyzed by multivariable logistic regression analysis. ResultsBoth olfactory cleft mucus and olfactory mucosa galectin-10 levels in patients with CRS with OD were significantly higher than those in patients with CRS without OD (all P < .001). Mucus galectin-10 levels were positively correlated with tissue eosinophils (r = 0.541, P = 0.002), olfactory cleft endoscopy scale (r = 0.498, P = 0.006), and olfactory cleft computed tomography scores (r = 0.432, P = 0.019) in patients with CRS. Mucus galectin-10 levels were negatively correlated threshold, discrimination, and identification (r = −0.589, P = 0.001), olfactory threshold (r = −0.522, P = 0.003), olfactory discrimination (r = −0.488, P = 0.007), and olfactory identification (r = −0.466, P = 0.011) scores. After adjusting for patient demographics and comorbidities, mucus galectin-10 levels were significantly associated with OD in patients with CRS (odds ratio, 1.299; P = .008). Mucus galectin-10 levels greater than 8.975 ng/mL were the best predictor of OD in CRS. ConclusionOlfactory cleft mucus galectin-10 is highly associated with OD in CRS.

Olfactory Function and Markers of Brain Pathology in Non-Demented Individuals with Autosomal Dominant Alzheimer's Disease.

Olfactory dysfunction is one of the earliest signs of Alzheimer's disease (AD), highlighting its potential use as a biomarker for early detection. It has also been linked to progression from mild cognitive impairment (MCI) to dementia. To study olfactory function and its associations with markers of AD brain pathology in non-demented mutation carriers of an autosomal dominant AD (ADAD) mutation and non-carrier family members. We analyzed cross-sectional data from 16 non-demented carriers of the Presenilin1 E280A ADAD mutation (mean age [SD]: 40.1 [5.3], and 19 non-carrier family members (mean age [SD]: 36.0 [5.5]) from Colombia, who completed olfactory and cognitive testing and underwent amyloid and tau positron emission tomography (PET) imaging. Worse olfactory identification performance was associated with greater age in mutation carriers (r = -0.52 p = 0.037). In carriers, worse olfactory identification performance was related to worse MMSE scores (r = 0.55, p = 0.024) and CERAD delayed recall (r = 0.63, p = 0.007) and greater cortical amyloid-β (r = -0.53, p = 0.042) and tau pathology burden (entorhinal: r = -0.59, p = 0.016; inferior temporal: r = -0.52, p = 0.038). Worse performance on olfactory identification tasks was associated with greater age, a proxy for disease progression in this genetically vulnerable ADAD cohort. In addition, this is the first study to report olfactory dysfunction in ADAD mutation carriers with diagnosis of MCI and its correlation with abnormal accumulation of tau pathology in the entorhinal region. Taken together, our findings suggest that olfactory dysfunction has promise as an early marker of brain pathology and future risk for dementia.

Unsupervised Clustering of Olfactory Phenotypes.

Current clinical classifications of olfactory function are based primarily upon a percentage of correct answers in olfactory identification testing. This simple classification provides little insight into etiologies of olfactory loss, associated comorbidities, or impact on the quality of life (QOL). Community-based subjects underwent olfactory psychophysical testing using Sniffin Sticks to measure threshold (T), discrimination (D), and identification (I). The cognitive screening was performed using Mini-Mental Status Examination (MMSE). Unsupervised clustering was performed based upon T, D, I, and MMSE. Post hoc differences in demographics, comorbidities, and QOL measures were assessed. Clustering of 219 subjects, mean age 51 years (range 20-93 years) resulted in 4 unique clusters. Cluster 1 was the largest and predominantly younger normosmics. Cluster 2 had the worst olfaction with impairment in nearly all aspects of olfaction and decreased MMSE scores. This cluster had higher rates of smoking, heart disease, and cancer and had the worst olfactory-specific QOL. Cluster 3 had normal MMSE with relative preservation of D and I, but severely impaired T. This cluster had higher rates of smoking and heart disease with moderately impaired QOL. Cluster 4 was notable for the worst MMSE scores, but general preservation of D and I with moderate loss of T. This cluster had higher rates of Black subjects, diabetes, and viral/traumatic olfactory loss. Unsupervised clustering based upon detailed olfactory testing and cognitive testing results in clinical phenotypes with unique risk factors and QOL impacts. These clusters may provide additional information regarding etiologies and subsequent therapies to treat olfactory loss.

Bloody olfaction? Confounding associations of sex and age on the influence of blood parameters and body weight on odor identification performance in healthy adults

Olfactory function and nutrition are closely related and may influence each other via metabolic parameters. However, the relationship between nutritional blood parameters and olfactory performance is still unclear. Inconclusive findings exist for specific blood parameters. In this extensive analysis, we examined the relationship between olfactory performance, measured with MONEX-40, as well as intensity and pleasantness ratings with 38 metabolic blood parameters, age, sex, and the anthropometric measurements body mass index (BMI) and body fat percentage (BFP). Therefore, we included data of 418 healthy, well-phenotyped Caucasians of the Enable cohort. We replicated age-dependent olfactory identification scores (p < 0.001) and found slight evidence for a body fat dependence measured with BFP (BF10 = 10.466). We further identified a sex difference only in middle-aged adults (p < 0.001) that could be explained by environmental factors. Several blood parameters correlated significantly with the MONEX-40 score (p < 0.05 – p < 0.001). However, these effects diminished after adjusting for sex and age (p > 0.9) that were identified as confounders. The same applies for BFP. In addition, no parameters were identified to correlate significantly with perceived olfactory intensity or pleasantness score if controlled for sex and age (p > 0.08). Our results suggest that metabolic blood parameters are not related to olfactory identification performance in a relevant manner and highlight the importance of controlling for sex and age in chemosensory research.

The Effects of Brain Magnetic Resonance Imaging Indices in the Association of Olfactory Identification and Cognition in Chinese Older Adults.

BackgroundOlfactory identification dysfunction frequently occurs in individuals with cognitive decline; however, a pathological mechanism linking the two has not been discovered. We aimed to study the association between olfactory identification and cognitive function, and determine the effects of brain regions atrophy therein.MethodsA total of 645 individuals (57.5% were female) from the Taizhou Imaging Study, who underwent cognitive and olfactory identification measurements, were included. A subsample of participants underwent brain magnetic resonance imaging (n = 622). Cognition was assessed with a neuropsychological battery. Olfactory identification was measured using a 12-item Sniffin’ Sticks test. Beta and logistic regressions were used to elucidate the association between olfactory identification and cognition, and the effects of brain regions atrophy in this association.ResultsDementia was diagnosed in 41 (6.4%) individuals (mean age = 64.8 years), and mild cognitive impairment (MCI) in 157 (24.3%) individuals (mean age = 64.4 years). Olfactory identification was associated with MMSE and MoCA (both P < 0.001) and specific cognitive domains (memory, executive function, visuospatial function, and language; all P < 0.05). Higher olfactory identification was associated with lower likelihood of MCI and dementia (P < 0.05). The amygdala volume was significantly related to olfactory identification, MMSE, MoCA, and language, and could attenuate the association between olfactory identification and cognitive function.ConclusionThe association between olfactory identification and cognition can be partly attributable to differences in amygdala volume, suggesting that the amygdala could be a shared neural substrate that links olfactory identification and cognitive function. Limitations of this study include that all these results were based on a cross-sectional study.

Anosmia Testing as Early Detection of SARS-CoV-2 Positivity; A Prospective Study under Screening Conditions.

Sudden onset of anosmia is a phenomenon often associated with developing COVID-19 disease and has even been described as an initial isolated symptom in individual cases. In this case-control study, we investigated the feasibility of this condition as a suitable screening test in a population at risk. We performed a prospective study with a total of 313 subjects with suspected SARS-CoV-2 infection. In parallel to routine PCR analysis, a modified commercial scent test was performed to objectify the presence of potential anosmia as a predictor of SARS-CoV-2 positivity. Furthermore, a structured interview assessment of the participants was conducted. A total of 12.1% of the study participants had molecular genetic detection of SARS-CoV-2 infection in the nasopharyngeal swab. It could be demonstrated that these subjects had a significantly weaker olfactory identification performance of the scents. Further analysis of the collected data from the scent test and medical history via random forest (Boruta) algorithm showed that no improvement of the prediction power was achieved by this design. The assay investigated in this study may be suitable for screening general olfactory function. For the screening of COVID-19, it seems to be affected by too many external and internal biases and requires too elaborate and selective pre-test screening.

Olfactory function trends in COVID-19 patients: a prospective cohort study

Background One of the most common symptoms in COVID-19 patients is olfactory and taste dysfunction. Aims/objectives This study aimed to evaluate the olfactory threshold, and identification using objective tests in the Iranian population. Material and methods The present study was a prospective cohort study conducted in 2020–2021 on clinically recovering COVID-19 patients. Olfactory function was evaluated at the baseline, 4–6 weeks, and 12 weeks later. Olfactory threshold assessment was performed using the Saba Sabalan kit. The Iranian version of the Pennsylvania Smell Identification Test (IR-SIT) was used for olfactory identification. The olfactory threshold was categorized as poor (<8) and good olfaction (≥8). Results In the present study, 111 patients were examined, including 55 men and 56 women (mean age 41.4 and 53.4 years, respectively). The mean olfactory threshold was better for men (7.2) than for women (6.6). Analysis showed age to have a negative relationship with good olfaction at baseline (OR = 0.93, p = .05). Using IR-SIT, only 29.7% had normal olfactory function. Using linear regression, smoking was found to be significantly related to baseline IR-SIT score (adjusted Beta <0.001, p = .03). Conclusions and significance Objective tests are appropriate methods for assessing olfactory dysfunction in COVID-19 patients. Further studies are recommended.

Correlations between Persistent Olfactory and Semantic Memory Disorders after SARS-CoV-2 Infection.

Background: One of the main symptoms of COVID-19 is hyposmia or even anosmia. Olfactory identification is most often affected. In addition, some cognitive disorders tend to appear following the infection, particularly regarding executive functions, attention, and memory. Olfaction, and especially olfactory identification, is related to semantic memory which manages general knowledge about the world. The main objective of this study was to determine whether semantic memory is impaired in case of persistent post COVID-19 olfactory disorders. Methods: 84 patients (average age of 42.8 ± 13.6 years) with post COVID-19 olfactory loss were included after consulting to the ENT department. The clinical evaluation was carried out with the Pyramid and Palm Tree Test, the word-retrieval task from the Grémots, the Sniffin’ Sticks Test and the Computerised Olfactory Test for the Diagnosis of Alzheimer’s Disease. Results: Semantic memory was impaired in 20% (n = 17) of patients, especially in the 19–39 age-group. The olfactory threshold was only significantly correlated with the semantic memory scores. Conclusions: Similar to all cognitive disorders, semantic disorders can have a negative impact on quality of life if left untreated. It is essential to carry out specific assessments of post COVID-19 patients to accurately determine their disorders and to put in place the best possible rehabilitation, such as speech and language therapy, to avoid quality-of-life impairment.

Olfactory dysfunction in type II diabetes: Therapeutic options and lessons learned from other etiologies – A scoping review

IntroductionOlfactory dysfunction (OD) is highly prevalent amongst type 2 diabetes mellitus (DM2) patients and has many associated health risks. For example, OD can lead to poor nutrition, safety issues related to diminished hazard detection, and increased mortality rates. While limited research exists about therapeutics for DM2-associated OD, recovery of olfactory function is better studied in other pathologic states. The objectives of this scoping review are to synthesize the existing data on interventions for DM2-associated OD and present the evidence for therapies that have been utilized for non-DM2-associated causes of OD. Additionally, the potential therapeutic opportunities for patients with DM2 are explored. MethodsA scoping review was conducted with a medical librarian to identify studies investigating treatments of DM2-related OD. 6 databases were searched (Embase, CINAHL, the Cochrane Library, Google Scholar, OVID Medline, and Web of Science). Studies were eligible if the primary discussion involved treatment of olfactory deficits in the context of DM2. All publication dates were included, and studies published in languages other than English were excluded. Results3631 articles were identified; 3 articles met inclusion criteria and underwent full text review. Hyperbaric oxygen (HBO), the DPP-4 inhibitor Linagliptin and the GLP-1 agonists Exenatide and Liraglutide are the only therapeutics that have been used in the context of DM2. Only HBO and GLP-1 agonists produced statistically significant improvements in olfactory identification. The literature regarding non-DM2-associated OD supports interventions such as olfactory training, dietary supplements, and intranasal insulin. Specifically, olfactory training was very effective in many contexts such as post-viral and traumatic OD while being affordable and non-invasive. ConclusionThis scoping review of olfactory rehabilitation options for DM2-induced OD demonstrates a paucity of prospective investigations of plausible therapeutics. Additionally, treatments for OD related to non-DM2-associated etiologies, such as olfactory training, are well-studied, efficacious, and should be investigated in the context of DM2. Future investigation has the potential to enhance the quality of clinical intervention for OD and improve short- and long-term outcomes for DM2 patients.

Odor Identification by Parkinson's Disease Patients Tested by Using Sniffin' Sticks versus Natural Spices.

Introduction Hyposmia is a frequent symptom of Parkinson's disease (PD), which greatly impacts patients' flavor perception and their quality of life. However, PD patients recognize some odors better than others. Identifying which food odors are still recognized by PD patients may be useful for flavor enhancement. Our aim was to evaluate the olfactory identification of Sniffin' Sticks and spice odorants in PD patients and healthy controls (HC), to identify the impact of synthetic odorants compared with real-life food and the impact of odor familiarity and pleasantness on odorant identification in PD patients. Methods Sniffin' Sticks odorant identification was evaluated in 80 PD patients and 105 age-matched HC. In a subset, the spice odorant identification was evaluated. Results The mean total score was higher for the Sniffin' Sticks than for the spice odor identification test in all participants (55.4% versus 22.5%). Sniffin' Sticks orange, peppermint, rose, and fish odorants were best correctly identified by PD patients, by 62.5, 53.8, 52.9, and 57.5%, respectively. Of the spice odor identification test, garlic and “no stimulus” were best correctly identified by PD patients, by, respectively, 38.2 and 67.6%. HC identified most Sniffin' Sticks odorants and spices better than PD patients. Odorant familiarity determined real-life food odorant identification. Conclusion This study demonstrates that some food odorants, both the commercial Sniffin' Sticks as natural odorants, are still recognized by PD patients. Sniffin' Sticks were better recognized compared with real-life odorants, by both HC and PD patients. Odorant familiarity determined PD patients' odorant identification; therefore, familiar food odorants may have potential for a future flavor enhancement. Implications. This is the first study, to our knowledge, to evaluate real-life food odor identification in PD patients. Our results provide a first step towards patient-appropriate flavor enhancement strategies in PD.

Impaired odor identification ability and olfactory hedonic capacity in children with elevated autistic traits

AbstractAtypical olfactory function in autism spectrum disorder has been documented in numerous studies, but little is known about its occurrence in individuals with autistic traits. The aim of the current study was to investigate odor identification ability and olfactory hedonic capacity in children with autistic traits. We recruited 415 children and measured their autistic traits by the Short Autism Spectrum Quotient. The Universal Sniff (U‐Sniff) test was used to measure odor identification ability and olfactory hedonic capacity. Olfactory hedonic capacity was also measured using the children's version of the Chemosensory Pleasure Scale (CPS‐C). Odor identification and olfactory hedonic capacity measured by CPS‐C were negatively correlated with autistic traits. Children with higher autistic traits exhibited poorer odor identification ability and olfactory trait hedonic capacity measured by CPS‐C but intact olfactory state hedonic capacity measured by odor pleasantness. These results pertaining to odor identification and olfactory hedonic capacity may be the endophenotypic markers for autism spectrum disorder.Practical ApplicationsOur study extends the knowledge on children with high autistic traits and provides a new perspective on olfactory identification ability and olfactory hedonic capacity in children with high autistic traits. In addition, our findings suggest olfactory testing may provide a new approach for detecting and understanding autism.

Olfactory identification disorders due to Alzheimer's disease: A new test from France to Quebec.

Olfactory identification disorder is regarded as an early marker of Alzheimer’s disease (AD) and of similar diagnostic significance of biological or cognitive markers. Premature damage of the entorhinal olfactory cortex, the hippocampus and the orbitofrontal cortex characterize AD and suggest a specific impairment of olfactory identification. The use of psychophysical olfactory identification tests in clinical diagnostic practice is therefore strongly recommended, but not required. As these widespread tests are rarely used, an innovative test, adapted to this target group has been developed. It has been used and validated in a routine care protocol at different Memory Centers in France and in Quebec, Canada. A total of 157 participants were recruited: including 63 Alzheimer’s patients and 94 healthy controls. The test was composed of 14 odorants diluted into 4 different concentrations. A computer interface generated randomization of 6 odors per participant and the automatic calculation of identification scores, of perceptual thresholds and of composite scores. All participants underwent a Mini Mental Scale Examination within the previous three months or on the same day of the olfactory test. The Alzheimer’s patients had a score between 20 and 30 and healthy controls participants had a score above 28 without any loss of points on recalled items. The results show that our olfactory identification test is able to significantly differentiate Alzheimer’s patients from healthy controls (p < 0.001), and to distinguish the French population tested from the Quebec population (p < 0.001). This study highlights an olfactory identification disorder as a target for early diagnosis of AD. Its cultural qualities make it a potential candidate for differentiated calibration between France and Quebec.

Effects of Nasal Airflow-Inducing Maneuver in Total Laryngectomy Patients Based on Changes to Olfactory Test Results: A Retrospective Study

Introduction: This study aims to retrospectively examine temporal changes in three aspects, i.e., olfactory threshold test, olfactory identification test, and olfactory perception on daily living test, caused by the use of the nasal airflow-inducing maneuver (NAIM). Methods: The olfactory threshold test (Sniffin’ Sticks test), olfactory identification test (Open Essence [OE]), and olfactory perception on daily living test (self-administered odor question; SAOQ) were administered to 46 patients who had undergone a total laryngectomy (NAIM Start group: 17; Using group: 19; and Nonuse group: 10). The tests were immediately performed after the NAIM and again after an average of 8 months. Results: In the NAIM Start group, all olfactory functions significantly improved in the second test compared with the first test (Sniffin’ Sticks test and OE, p < 0.01 for both; self-administered, p < 0.05). Additionally, in terms of the intergroup changes among scores for the Sniffin’ Sticks test and OE, the NAIM Start group showed a significant difference compared with all of the other groups (Start group > Using and Nonuse group, p < 0.01). The NAIM Using group did not exhibit any significant changes. In the NAIM Nonuse group, olfactory identification function was lower in the second test compared with the first test and showed a trend toward a significant difference (OE, p < 0.1). Temporal changes in SAOQ showed a significant increase in all intragroup comparisons. However, there were no significant differences observed in terms of the changes between the groups. Conclusion: The results demonstrated that even in those who were not using NAIM and undergoing olfactory rehabilitation after laryngectomy (NAIM Start group), the subsequent daily use of NAIM and voluntary rehabilitation aided in the recovery of olfactory function to the same level as that in the already using NAIM group. SAOQ results were considered because of the experimenter effect and they appeared to be unrelated to use NAIM. This study showed that in total laryngectomy patients who did not receive olfactory rehabilitation, olfactory identification was reduced.

The Examination of Olfactory Function and Mucocilliary Transport in Gas Station Officers in Makassar, Indonesia

Introduction: Chronic exposure to fuel oil can cause chemical burns to the olfactory epithelium, which can cause anosmia. This study aimed to compare mucociliary transport time and olfactory function between operator and non-operator officers at gas stations. Methods: This cross-sectional study was conducted from September to November 2020 and involved 40 subjects divided into two equal groups each consisting of 20 gas station operators and non-operators, respectively. The examination of mucociliary transport time was carried out by saccharin test, while the olfactory function was examined by assessing e olfactory threshold, discrimination, and identification (TDI) score using the Sniffin sticks test. Results: There was a significant difference in the mean mucociliary transport time and olfactory function between gas station operators and non-operators (P&lt;0.001). In addition, there was also a significant correlation between the mucociliary transit time and olfactory function (p&lt;0.05), with a strong negative correlation coefficient (r=-0.620). Therefore, the longer the mucociliary transit time, the gas station attendant's olfactory function will decrease. Conclusion: mucociliary transport time and olfactory function in non-operator public gas station officers were better than operators, probably because inhalation of chemical pollutants induces the release of proinflammatory cytokines, chronic inflammation of the nasal mucosa results in impaired olfactory cells and mucin glands.

Relationship between Olfactory Function and BMI in Normal Weight Healthy Subjects and Patients with Overweight or Obesity.

Smell plays a critical role in food choice and intake by influencing energy balance and body weight. Malnutrition problems or modified eating behaviors have been associated with olfactory impairment or loss. The obesity epidemic is a serious health problem associated with an increased risk of mortality and major physical comorbidities. The etiopathogenesis of obesity is complex and multifactorial, and one of the main factors contributing to the rapid increase in its incidence is the environment in which we live, which encourages the overconsumption of foods rich in energy, such as saturated fats and sugars. By means of the “Sniffin’ Sticks” test, we measured the olfactory threshold, discrimination and identification score (TDI score) in patients of the Obesity Center of the University Hospital (OC; n = 70) and we compared them with that of healthy normal weight controls (HC; n = 65). OC patients demonstrated a significantly lower olfactory function than HC subjects both general and specific for the ability to discriminate and identify odors, even when they were considered separately as females and males. For OC patients, a negative correlation was found between body mass index (BMI) and olfactory scores obtained by each subject, both when they were divided according to gender and when they were considered all together. Besides, normosmic OC patients showed a significantly lower BMI than hyposmic ones. A reduced sense of smell may contribute to obesity involving the responses of the cephalic phase, with a delay in the achievement of satiety and an excessive intake of high-energy foods and drinks.

Brain Structure as a Correlate of Odor Identification and Cognition in Type 2 Diabetes.

Background: It has been reported that type 2 diabetes (T2DM) is associated with olfactory identification (OI) impairments and cognitive decline. However, the relationship between OI impairments and cognitive decline is largely unknown in T2DM patients.Methods: Sixty-eight T2DM patients and 68 healthy controls underwent 3D-T1 MRI scans, olfactory and cognitive assessments. The cortical thickness of olfaction-related brain regions, olfactory and cognitive scores were compared between groups. Correlation analyses were carried out among cognition, olfaction, and cortical thickness of olfaction-related brain regions.Results: First, the cognitive and olfactory test scores of T2DM patients were lower than healthy subjects. Second, higher olfactory scores were associated with increased cortical thickness in the left parahippocampal gyrus and bilateral insula in T2DM. Third, higher olfactory scores were associated with higher cognitive performance in T2DM. Fourth, some cognitive performances were related to cortical thickness in the left parahippocampal gyrus and left insula in T2DM.Conclusion: These findings indicated that olfactory dysfunction may be useful for future applications that attempt to predict cognitive decline or develop tailored therapies in T2DM patients.

Molecular and Phenotypic Expansion of Alström Syndrome in Chinese Patients.

Alström syndrome (ALMS) is a rare inherited metabolic disease and ciliopathy. Large cohorts of ALMS are lacking around the world. Detailed genetic and phenotypic data were obtained from all affected individuals. Olfactory function was evaluated by the Chinese Smell Identification Test and facial pattern was analyzed with Face2gene. Fifty ALMS patients were included in this study, aged from 0.3 to 21.7 years old. Sixty-one ALMS1 variants in 50 patients from 47 different families were confirmed, including 59 truncating and two exon deletions. Twenty-four of those variants were novel. We also summarized all previously reported cases of Chinese ALMS patients (69 patients) and identified specific and common variants within the Chinese population. Besides, the Chinese Smell Identification Test scores in patients was lower than that in controls (11.97 Vs. 10.44, p < .05), indicating olfactory identification impairments in ALMS patients. The facial pattern in ALMS patients was also distinctive from that of the controls (p < .05). In conclusion, this is the largest cohort of Chinese ALMS patients. We have successfully identified both specific and common variants in our cohort. We found a new phenotype of olfactory impairments in ALMS patients through a case-control study.

Cognitive Function and Olfactory Impairment in Community-Dwelling Older Adults Attending a Salon.

Background:Early detection, treatment, and care are important for the prevention of dementia. Though olfactory impairment has been reported to be associated with mild cognitive impairment (MCI), there are few reports involving community-dwelling older adults with no difficulty in daily life in Japan.Objective:This study aimed to identify the frequency of MCI in community-dwelling elderly people attending community salons in a city with a high aging population, and to determine the usefulness of a pocket olfactory discrimination test.Methods:We recruited 268 independent older adults attending community salons. The Japanese version of the MCI Screen was used to evaluate cognitive function, defining MCI as <49.8 out of 100 scores of the memory performance index (MPI). The Japanese version of the University of Pennsylvania Smell Identification Test (UPSIT-J) was used for olfactory discrimination and the number of correct answers out of 4 questions was noted.Results:Of the salon participants, 138 (51.5%) were classified as having MCI. As the number of correct answers on the olfactory test decreased, the percentage of participants with MCI increased. The MPI score of the low UPSIT score group was significantly lower than that of the high UPSIT score group.Conclusions:This study revealed that approximately half of the elderly local residents living without daily problems were suspected of having MCI. The UPSIT-J-4 is a simple olfactory identification test, and can be used at any time and any place. It is useful for screening cognitive function via olfactory identification in a salon-like setting.