Association of olfactory and gustatory function with memory among community-dwelling independent older adults

Background

This study examined the association between memory function and reduced olfactory and gustatory function among independent community-dwelling older adults.

Methods

This cross-sectional study included 127 older adults (65.4% women). We assessed their memory, odor, and taste identification skills. Open essence (OE) test and taste strips (TS) were used to identify hyposmia (OE test ≤6) and hypogeusia (TS test ≤8), respectively.

Results

Participants with severe hyposmia had significantly poorer memory functions compared to participants without severe hyposmia. After adjusting for covariates, multivariate logistic regression models revealed a significant association between immediate recognition performance and a decreased likelihood of severe hyposmia (odds ratio = 0.65, 95% confidence interval = 0.47-0.90). We observed no significant association between taste function and memory.

Conclusions

Memory function may be associated with olfactory impairment but not with gustatory function in older adults.

The "Sniffin' Kids-PT" test: A smell test variant for Portuguese children

OBJECTIVE

Olfactory tests tailored for children are essential, as diagnosing olfactory dysfunction at these ages can be challenging. The 16-item "Sniffin' Sticks" is reliable and easy to perform. To the best of our knowledge, there is currently no validated olfactory test for the Portuguese pediatric population. This study aimed to adapt and validate the "Sniffin' Sticks" olfactory test for the Portuguese pediatric population.

METHODS

Between August 2020 and September 2021, 354 children aged between 6 and 17years old enrolled in the study, 336 healthy children with a normal sense of smell, and 18 anosmic children with Kallmann syndrome. The study consisted of two parts. Firstly, the "Sniffin' Sticks" olfactory identification test was applied to healthy children and the odors with statistically significant low identification rates were excluded. A modified version of "Sniffin' Sticks" was defined and named "Sniffin' Kids-PT" test. Secondly, normative data were assessed and test-retest and validation tests were performed.

RESULTS

Apple and Cloves odors were identified with a low rate and were excluded from the "Sniffin' Sticks" olfactory test. In the modified 14-item "Sniffin' Kids-PT", scoring <6 (from 6-8years old), <7 (from 9-11years old) or <8 (from 12-14years old and 15-17years old) was indicative of olfactory dysfunction. The test-retest reliability was good (r=0.81; P<0.001) and the differences between scores of healthy children and anosmic children were statistically significant (U213=13.00; P<0.001).

CONCLUSION

The modified "Sniffin' Kids-PT" is a reliable test to discriminate between normosmia and olfactory dysfunction in Portuguese children over 5years old.

qU-Sniff - the development of a short version of the Universal "Sniffin' Sticks" test

OBJECTIVES

Extensive olfactory testing is sparsely applied in pediatric patients in clinical routine especially because of its time taking nature. Therefore a 5-item odor identification test (quick "U-Sniff", "qU-Sniff") from the 12-item "U-Sniff" test was developed.

METHODS

A total of 724 normosmic children between 6 and 17 years of age, divided in four age groups, were included in this retrospective study. Additionally, 17 children with congenital anosmia in the same age range were included. To calculate test-retest reliability 90 participants from the healthy group were tested twice.

RESULTS

The five most correctly identified odors from the 12-item "U-Sniff" test were: coffee (98 %), peach (95 %), flower (90 %), fish (88 %) and onion (84 %). Normosmic participants scored 4.71 ± 0.62 points on the "qU-Sniff" test. A significant correlation between results of the 12-item and 5-item test (n = 724; rs = 0.580; p < 0.001) and a significant test-retest reliability (rs = 0.626, p < 0.001) were shown. For "qU-Sniff" validation a ROC analysis to distinguish between anosmic patients and healthy controls was conducted for each age group separately. AUCs were as followed: i) 0.963 ± 0.018, p < 0,001; ii) 0.978 ± 0.013, p < 0.001; iii) 0.992 ± 0.006, p < 0.001; iv) 0.994 ± 0.005, p < 0.001. The cut-off value to determine anosmic and normosmic participants was <4 points.

CONCLUSION

With the "qU-Sniff" test, we present a short screening tool for clinical routine with <4 points as cut-off to initiate more detailed olfactory testing.

Olfactory function assessment of migraine patients by using the Sniffin' sticks test: A clinical study

OBJECTIVE

This as a cross-sectional controlled clinical study. We hypothesis that the olfactory functions in migraine patients may differ from the healthy controls. In this study, we evaluated the olfactory functions by using a Sniffin' Sticks test battery, which is a reliable and semi quantitative test to evaluate for olfactory dysfunction.

METHODS

Patients above 18 years of age who had migraine received a definitive diagnosis of migraine from experienced headache specialists based on the criteria of The International Classification of Headache Disorders-3 were included. Odor threshold, discrimination, and identification parameters were assessed using the "Sniffin' Sticks" test.

RESULTS

One-hundred and one migraine patients (age [mean ± SD], 36.9 ± 10.4 years; range, 18-60 years) and sixty healthy volunteers (age 34.5 ± 13.2 years, range 18-65 years) participated in our study. The median odor threshold score [percentiles 25th-75th] was 8.3 [6.5-9.8] for the migraine group during attack free period and 4.5[3.6-6.0] for the control group. It was found that the migraine group had a median odor discrimination score of 10.0 [10.0-13.0] and the control group 12.0 [11.0-13.0]. These differences were statistically significant (p < 0.001 and p = 0.032 respectively). The median odor discrimination and identification scores were statistically significant higher for the participants with higher educational level group than in those of lower educational group (p < 0.0001). The median odor discrimination and identification scores of those without allodynia (12.0 [10.0-14.0] and 13.0 [10.0-13.0] respectively) were higher than that of those with allodynia (11.0 [9.0-12.0] and 11.0 [10.0-13.0] respectively) (p = 0.037 and p = 0.034 respectively).

CONCLUSIONS

We found that the odor thresholds, discrimination and identification scores of the migraine group demonstrate differences from those of the healthy group and in relation to allodynia.

Flavor characteristics of peeled walnut kernels under two-steps roasting processes

Currently, the effects of roasting methods on the flavor profile of peeled walnut kernels (PWKs) remain unknown. The effects of hot air binding (HAHA), radio frequency (HARF), and microwave irradiation (HAMW) on PWK were evaluated using olfactory, sensory, and textural techniques. Solvent Assisted Flavor Evaporation-Gas Chromatography-Olfactometry (SAFE-GC-O) identified 21 odor-active compounds with total concentrations of 229 μg/kg, 273 μg/kg and 499 μg/kg due to HAHA, HARF, and HAMW, respectively. HAMW exhibited the most prominent nutty taste, with the highest response among roasted milky sensors with the typical aroma of 2-ethyl-5-methylpyrazine. HARF had the highest values for chewiness (5.83 N·mm) and brittleness (0.68 mm); however, these attributes did not contribute to the flavor profile. The partial least squares regression (PLSR) model and VIP values showed 13 odor-active compounds were responsible for the sensory differences from different processes. The two-step treatment with HAMW improved the flavor quality of PWK.

Odor identification errors reveal cognitive aspects of age-associated smell loss

Human olfaction can be extraordinarily sensitive, and its most common assessment method is odor identification (OID), where everyday odors are matched to word labels in a multiple-choice format. However, many older persons are unable to identify familiar odors, a deficit that is associated with the risk of future dementia and mortality. The underlying processes subserving OID in older adults are poorly understood. Here, we analyzed error patterns in OID to test whether errors could be explained by perceptual and/or semantic similarities among the response alternatives. We investigated the OID response patterns in a large, population-based sample of older adults in Sweden (n = 2479; age 60-100 years). Olfaction was assessed by a 'Sniffin ́ TOM OID test with 16 odors; each trial involved matching a target odor to a correct label among three distractors. We analyzed the pattern of misidentifications, and the results showed that some distractors were more frequently selected than others, suggesting cognitive or perceptual factors may be present. Relatedly, we conducted a large online survey of older adults (n = 959, age 60-90 years) who were asked to imagine and rate the perceptual similarity of the target odors and the three corresponding distractors (e.g. "How similar are these smells: apple and mint?"). We then used data from the Swedish web corpus and the Word2Vec neural network algorithm to quantify the semantic association strength between the labels of each target odor and its three distractors. These data sources were used to predict odor identification errors. We found that the error patterns were partly explained by both the semantic similarity between target-distractor pairs, and the imagined perceptual similarity of the target-distractor pair. Both factors had, however, a diminished prediction in older ages, as responses became gradually less systematic. In sum, our results suggest that OID tests not only reflect olfactory perception, but also likely involve the mental processing of odor-semantic associations. This may be the reason why these tests are useful in predicting dementia onset. Our insights into olfactory-language interactions could be harnessed to develop new olfactory tests that are tailored for specific clinical purposes.

Olfactory Dysfunction in Schizophrenia: Evaluating Olfactory Abilities Across Species

Though understudied relative to perturbations in the auditory and visual domains, olfactory dysfunction is a common symptom of schizophrenia. Over the past two decades, the availability of standardized assessments to quantify human olfactory abilities, and enhance understanding of the neurophysiology supporting olfaction, has increased, enabling a more thorough characterization of these deficits. In contrast to other psychiatric conditions for which olfactory dysfunction has been observed (e.g., major depressive disorder, bipolar disorder, Alzheimer's disease), the impairments observed in schizophrenia are particularly global and profound. At this level, such deficits in olfactory abilities likely impact the enjoyment of food, detection of environmental hazards, and influence social relationships. More broadly, the study of olfactory phenotypes in schizophrenia presents new avenues for detection of those at-risk for the condition, identification of therapeutic targets for treatment development, and for the characterization of novel animal models relevant to schizophrenia and psychosis. This review will consider the olfactory performance of individuals with schizophrenia in domains for which standardized assessments are available (odor sensitivity, discrimination, identification, and memory). Paradigms available for assessing these abilities in rodents will also be discussed with the aim of facilitating translation. Thus, future studies will be able to include cross-species translation of mechanisms relevant to olfactory function and cognition, what has gone awry in the disease state, and test potential therapeutics.

Hedonic perception of odors in children aged 5-8 years is similar across 18 countries: Preliminary data

OBJECTIVE

Olfactory preference emerges very early in life, and the sense of smell in children rapidly develops until the second decade of life. It is still unclear whether hedonic perception of odors is shared in children inhabiting different regions of the globe.

METHODS

Five-hundred ten healthy children (N = 510; n_girls = 256; n_boys = 254) aged from 5 to 8 years from 18 countries rated the pleasantness of 17 odors.

RESULTS

The hedonic perception of odors in children aged between 5 and 8 years was rather consistent across 18 countries and mainly driven by the qualities of an odor and the overall ability of children to label odorants.

CONCLUSION

Conclusions from this study, being a secondary analysis, are limited to the presented set of odors that were initially selected for the development of U-Sniff test and present null findings for the cross-cultural variability in hedonic perception of odors across 18 countries. These two major issues should be addressed in the future to either contradict or replicate the results presented herewith. This research lays fundament for posing further research questions about the developmental aspects of hedonic perception of odors and opens a new door for investigating cross-cultural differences in chemosensory perception of children.

Disrupted olfactory functional connectivity in patients with late-life depression

BACKGROUND

Odor identification (OI) impairment increases the risk of Alzheimer's disease and brain abnormalities in patients with late-life depression (LLD). However, it remains unclear whether abnormal functional connectivity (FC) of olfactory regions is involved in the relationship between OI impairment and dementia risk in LLD patients. The current study aims to explore the olfactory FC patterns of LLD patients and how olfactory FCs mediate the relationship between OI and cognition.

METHODS

A total of 150 participants underwent resting-state functional magnetic resonance imaging and psychometric and olfactory assessments. The primary and secondary olfactory regions were selected as regions of interest to investigate olfactory FC patterns and their association with OI and cognitive performance in LLD patients.

RESULTS

Compared with LLD patients without OI impairment and normal controls, LLD patients with OI impairment exhibited increased FC between the left orbital frontal cortex (OFC) and left calcarine gyrus, between the left OFC and right lingual gyrus, between the right OFC and right rectus gyrus, and decreased FC between the right piriform cortex and right superior parietal lobule. Additionally, these abnormal FCs were associated with scores of OI, global cognition and language function. Finally, the FC between the right piriform cortex and right superior parietal lobule exhibited a partially mediated effect on the relationship between OI and MMSE scores.

LIMITATIONS

The present study did not exclude the possible effect of drugs.

CONCLUSION

LLD patients with OI impairment exhibited more disrupted olfactory FC (a decrease in the primary olfactory cortex and an increase in the secondary olfactory cortex) than LLD patients with intact OI, and these abnormal FCs may serve as potential targets for neuromodulation in LLD patients to prevent them from developing dementia.

Olfactory capacity in anorexia nervosa: correlations with set-shifting ability

PURPOSE

The purpose of this study is to examine olfactory capacity in adults with anorexia nervosa (AN), in terms of odor identification and odor threshold and search for possible correlations between odor identification and cognitive flexibility in this population.

METHODS

Thirty-nine patients diagnosed with AN and 60 healthy participants, participated. Odor identification was assessed using the University Pennsylvania Smell Identification Test and a two alternative forced choice, ascending method with n-butanol was used to assess odor threshold. Cognitive flexibility was determined using the Intra/Extra-Dimensional Set-Shift test (IED), a subtest of the Cambridge Neuropsychological Test Automated Battery (CANTAB).

RESULTS

Patients with AN presented a poorer performance in odor identification compared with controls (p = 0.001). No differences were found in odor threshold, between the two groups. Patients with AN exhibited poor cognitive flexibility compared with controls (p = 0.003). A significant correlation between odor identification and cognitive flexibility was documented in AN (p = 0.01), but not in controls.

CONCLUSION

Our findings suggest that olfactory capacity is altered in AN: Qualitative characteristics of olfaction were affected in patients with AN (lower odor identification), while there was no difference in quantitative characteristics (odor threshold) compared with controls. Furthermore, odor identification in AN was correlated to cognitive flexibility.

LEVEL OF EVIDENCE

Level III: case-control analytic study.

Olfactory impairment in men and mice related to aging and amyloid-induced pathology

Olfaction, or the sense of smell, is one of the most ancient senses in men and mice, important for a large variety of innate and acquired behaviors. Clinical data reveal an early impairment of olfaction during normal aging and in the course of neurodegenerative diseases, but the underlying cellular/molecular mechanisms remain obscure. In the current review, we compare different aspects of the aging- and Alzheimer's disease related impairment of olfaction in men and mice, aiming at the identification of common morbidities and biomarkers, which can be analyzed in detail in the appropriate mouse models. We also identify common, often interdependent (patho)physiological pathways, including but not limited to extracellular amyloid depositions, neuroinflammation, ɛ4 allele of the apolipoprotein E, CNS insulin resistance, and the impairment of adult neurogenesis, to be targeted by basic and clinical research.

Odor identification performance in children using the "U-Sniff" test - Administered by an untrained person

OBJECTIVE

The examination of olfactory function of patients with psychophysical olfactory tests such as the "Sniffin' Stick" test is a central component of any olfactory clinical diagnostics and clinical trials. Because olfactory disorders can also occur in childhood, reliable, valid and time-efficient olfactory tests are important. With the "U-Sniff", a child-friendly odor identification test that has already been sufficiently validated is available The aim of this study was to investigate whether untrained persons (e.g. parents with their children) are able to administer the "U-Sniff" odor identification test with appropriate guidance.

METHOD

A total of 80 kindergarten children, aged 6 years, underwent an odor identification test. Half of the children were tested by their parents and the other half by a trained examiner. In addition, the examiner performed a concentration test (Kaseler Konzentrationsaufgaben). The results of the two groups were compared.

RESULTS

All children completed the rapid testing protocol. No significant differences between the results of the two testing procedures occurred. On average an odor identification score of 9.68 ± 2.02 points (mean ± SD) was reached in the examiner's group while 9.65 ± 2.38 points were observed in the parents' group.

CONCLUSION

It can be concluded that this study presents a new testing procedure using the "U-Sniff" odor identification test for children by untrained persons. Further validation of this test procedure examining olfactory impaired children should follow.

Association of pediatric idiopathic intracranial hypertension with olfactory performance

OBJECTIVE

To assess the association between pediatric Idiopathic intracranial hypertension (IIH) and olfactory performance.

METHODS

A cross-sectional comparative study was conducted including 17 patients under 18 years diagnosed with IIH at a tertiary hospital and 17 healthy age- and sex-matched subjects. All participants underwent the semi-objective chemosensory Sniffin' Sticks test for evaluation of odor threshold (OT), indicative of peripheral olfactory function, and odor identification (OI), reflecting higher cognitive olfactory processing. Scores were compared and referred to the updated normative values. Demographic, clinical, and neuroimaging data were collected from the medical files. The patients with IIH were reassessed for olfactory function and clinical state at the subsequent follow-up, under treatment.

RESULTS

Compared to controls, the IIH group had a significantly lower mean OT score (6.41 ± 3.43 vs 10.21 ± 2.79, p = 0.001) and higher rate of OT score below the 10th percentile for age and sex according to the normative values (47.1% vs 0%, p = 0.001). There was no significant between-group difference in mean OI scores (9.82 ± 1.63, vs 10.59 ± 1.84, p = 0.290). OT scores were not associated with sex, age, body mass index, neuroimaging abnormalities, or lumbar puncture opening pressure. At the follow-up assessment, the OT scores were improved (9.36 ± 4.17 vs 6.7 ± 3.32, p = 0.027) whereas the OI scores were unchanged (9.88 ± 2.5 vs 9.69 ± 1.58, p = 0.432).

CONCLUSIONS

As reported in adults, children and adolescents with IIH appear to have a selective reversible deficit in olfactory detection threshold, which may imply a reduction in peripheral olfactory perceptual ability. Future studies should examine the predictive value of olfactory function for IIH.

Analysis of the effects of subthalamic nucleus deep brain stimulation on somatosensation in Parkinson's disease patients

OBJECTIVE

Despite the subthalamic nucleus (STN) deep brain stimulation (DBS) is a treatment commonly used to ameliorate the motor symptoms of Parkinson's disease (PD), its effects on somatosensation is unclear. The purpose of this study was to investigate the potential effects of DBS on temperature, proprioceptive, tactile, exteroceptive, pain and cortical sensations, and odor identification in PD patients.

METHODS

The study included 14 patients (with a mean age of 59.78 ± 11.03 years; range, 44-70 years) with idiopathic PD who underwent DBS surgery for movement disorders caused by PD at the same Neurosurgery Department. All patients were tested while DBS was turned on (DBS-ON) and off (DBS-OFF). To clearly observe the effect of removing stimulation off, DBS devices were turned off by experimental clinical personnel for a minimum duration of 30 min prior to examination. Temperature, proprioceptive, tactile, exteroceptive, pain and cortical sensations, and odor identification were examined.

RESULTS

We found that two-point discrimination was significantly lower during DBS-ON than DBS-OFF (p = 0.031). Tactile sensation and kinesthesia deviation degree were lower during DBS-ON than DBS-OFF, but were non-significant (p > 0.05). The number of correct answers on an assessment of graphesthesia was higher during DBS-ON, but was non-significant as well (p > 0.05). Odor identification was better during DBS-OFF.

CONCLUSIONS

DBS may have an effective role to improve somatosensation and DBS-related benefits may not be explained by improvements in motor function alone, but rather by enhanced somatosensory processing. Further studies with larger study groups are needed.

Associations of olfactory dysfunction with anthropometric and cardiometabolic measures: Findings from the 2013-2014 national health and nutrition examination survey (NHANES)

We examined associations of olfactory dysfunction with anthropometric and cardiometabolic measures in a nationally representative sample of US adults. In the 2013-2014 National Health and Nutrition Examination Survey (NHANES), 3,815 participants, 40 years and older, completed a standardized taste and smell protocol, which consisted of an 8-item odor identification test and a chemosensory questionnaire. Measured dysfunction was incorrect identification of ≥3 of 8 odors; self-reported dysfunction was affirmative response to either a recent smell problem, worse ability since age 25, or phantosmia. Survey-weighted linear regression models tested associations of olfactory dysfunction with body mass index (BMI), waist circumference (WC), blood pressure, serum total cholesterol (TC) with fractions, triglycerides, and glucose levels. Models were adjusted for age, race, education, physical activity, self-reported general health condition, smoking history, and income-to-poverty ratio, stratifying by sex and age group (middle-age 40-64 years; older ≥65 years). Relative to normal, measured olfactory dysfunction was associated with lower BMI [β=-1.6 (95% CI: -3.2, -0.01)] in older men. In middle-age women, dysfunction was associated with higher BMI and WC, whether assessed by examination [β's for BMI=3.1 (0.6, 5.5), WC=5.0 (0.3, 9.8)] or self-report [β's for BMI=2.5 (0.6, 4.3), WC=6.1 (2.2, 9.9)]. Measured dysfunction was associated with significantly higher TC [β=12.8 (7.5, 18.1)] and LDL [β=18.1 (9.1, 27.2)] among older men, but significantly lower TC [β=-15.0 (-25.0, -5.7)] and marginally lower LDL [β=-12.0 (-25.0, 1.2)] among older women. Between measured dysfunction and fasting glucose, the association was inverse [β=-7.9 (-13.0, -2.6)] among middle-age men, but positive [β=15.6 (1.5, 29.7)] among older women. No significant associations were observed with blood pressure levels. In conclusion, among US adults ≥40 years, olfactory dysfunction is associated with anthropometric and glucose and lipid levels, with associations varying by sex and age group.

Normative data for olfactory threshold and odor identification in children and adolescents

OBJECTIVE

Although previous studies have demonstrated the feasibility and validity of olfactory testing in children and adolescents using the "Sniffin' Sticks" odor threshold and "U-Sniff" odor identification test, normative data obtained in a large sample for these tests are missing. Aim of this study was therefore to obtain normative data of healthy children and adolescents for olfactory assessment.

MATERIAL AND METHODS

Olfactory testing was conducted using the "Sniffin' Sticks" olfactory threshold (THR) and the 12-item "U-Sniff" odor identification (ID) test. The data were collected from 490 children and adolescents (234 girls, 257 boys) between the age of 6 and 17 years (mean age: 11.2 ± 3.4 years). In line with previous studies, participants were divided into subgroups regarding their age: i) 6-8 years, ii) 9-11 years, iii) 12-14 years and iv) 15-17 years.

RESULTS

All participants were able to perform the task. Neither sex nor age significantly influenced THR. Girls outperformed boys in ID. In addition, the youngest age group scored lower than the three other age groups on the "U-Sniff" odor identification test. Using the 10th percentile to distinguish normosmia from a reduced sense of smell the following values were obtained for the four age groups: i) THR 4.25 points, ID 7 points, ii) THR 5.0 points, ID 9 points, iii) THR 4.75 points, ID 10 points and iv) THR 5.5 points, ID 10 points.

CONCLUSION

The present study provides normative data for olfactory assessment in children and adolescents using both an olfactory threshold and a suprathreshold test to distinguish between normosmia and a reduced sense of smell using the 10th percentile.

Influence of chronic diseases on the olfactory function in children

The association between smell impairment and chronic diseases has been reported in some studies in adults. Such information is not available for chronic diseases in children. The aim of this study was to examine olfactory function of children with chronic diseases such as diabetes mellitus type 1, hypothyroidism, and bronchial asthma in combination with allergic rhinitis in comparison to healthy controls. The data were obtained from n = 205 participants (104 boys, 101 girls) between the age of 6 and 17 years. Seventy-eight of the participants were healthy controls, n = 43 had diabetes mellitus type 1, n = 50 suffer from allergic rhinitis or bronchial asthma, and 34 presented a reduced function of their thyroid in medical history. All participants underwent olfactory testing including olfactory threshold using "Sniffin' Sticks" and odor identification using the "U-Sniff" test. In addition, a depression inventory and cognitive testing using the Ravens Progressive Matrices was performed. No significant difference in olfactory function was observed for any of the chronic diseases in children in comparison to healthy controls. Further analysis showed a trend in significance for a subpopulation of children with bronchial asthma and comorbidities performed worse on the olfactory threshold test compared to patients with bronchial asthma without comorbidities. Pediatric patients suffering from chronic diseases scored higher on the depression inventory compared to healthy controls.Conclusion: In conclusion, this study demonstrates that the influence of chronic diseases (bronchial asthma, diabetes mellitus type 1 and hypothyroidism) on olfactory function in childhood, if any, seems to be insignificant. This is partly in contrast to adult patients. Further research should be conducted in a subgroup of patients with bronchial asthma, allergic rhinitis, and atopic dermatitis or other comorbidities to better understand the association of allergic diathesis and olfactory function and the putative pathogenesis of olfactory dysfunction. What is known: • The association between smell impairment and chronic diseases has been reported in some studies in adults. • Such information is not available for chronic diseases in children. What is new: • The influence of chronic diseases (bronchial asthma, diabetes mellitus type 1, and hypothyroidism) on olfactory function in childhood, if any, seems to be insignificant. • In patients with bronchial asthma and allergic rhinitis, only a subgroup of patients with additional comorbidity (atopic dermatitis) showed a tendency to a reduced sense of smell.

The identification and health risk assessment of odor emissions from waste landfilling and composting

Odor nuisance is the main incentive for Not In My Back Yard campaigns around municipal solid waste (MSW) waste disposal facilities, and the odor identification is of significance for the understanding of the odor properties from MSW with different disposal methods. In this study, odor emissions from different stages at two large-scale working MSW disposal facilities, i.e., landfill (LF) and compost plant (CP), were distinguished with the same MSW feedstock in one city. It was found that CP suffered the heavier odor pollution and the characteristics of odorants changed significantly, especially the pile-turning workshop. Sulfides and aromatics were the main concentration contributors for LF, while that for CP were NH₃ and oxygenated compounds. Significant correlations between odor concentration and halogenated compounds, sulfides (r² = 0.945, 0.898, p<0.05, n = 12) were merely observed in CP. The priority odor pollutants of LF were H₂S, benzene and NH₃, while that of CP was NH₃, ethyl acetate and benzene with a descending order. With regarding to their contributions for occupational exposure, the carcinogenic risk was negligible for these facilities, but H₂S of LF might bring non-carcinogenic risk to on-site workers.

Psychophysical testing of smell and taste function

The senses of smell and taste are largely underappreciated by laypersons and medical professionals alike. Unlike vision, hearing, balance, and touch, they are rarely evaluated quantitatively in the clinic, even though hundreds of thousands of persons seek medical help annually for disorders of these senses. Chemosensory disorders impact quality of life, including the flavor of foods and beverages, and compromise the ability to detect such environmental hazards as fires, leaking natural gas, and spoiled foodstuffs. Moreover, olfactory dysfunction can be a harbinger for Alzheimer's and other neurodegenerative diseases, and is known to triple the likelihood of mortality in older persons over the course of 4 or 5 years. Without accurate testing, one cannot establish the veracity of a patient's complaint, the probability of malingering, the impact of treatments, and whether the degree of dysfunction is normal relative to a patient's age and sex. This chapter provides basic information as to how to measure both the senses of smell and taste, as well as normative data for several clinical smell and taste tests.

Olfactory function and neurocognitive outcomes in old age: The Atherosclerosis Risk in Communities Neurocognitive Study

INTRODUCTION

We tested the hypothesis that poor sense of smell is associated with lower cognitive function and higher mild cognitive impairment (MCI) prevalence.

METHODS

Olfaction, measured by the Sniffin' Sticks test, was categorized as olfactory impairment (OI) (score ≤6) or no OI (score >6). MCI was adjudicated based on review of a neuropsychological examination. Linear regression estimated the mean difference in cognitive factor scores, and log-binomial regression quantified MCI prevalence among participants with versus without OI.

RESULTS

Participants with OI had lower mean factor scores (memory: -0.27 standard deviation [SD], 95% confidence interval [CI]: -0.35 to -0.19; language: -0.24 SD, 95% CI: -0.30 to -0.17; executive function/processing speed: -0.09 SD, 95% CI: -0.12 to -0.06; and general cognitive performance: -0.25 SD, 95% CI: -0.30 to -0.20). OI was also associated with MCI (n = 204; prevalence ratio = 1.56, 95% CI: 1.37, 1.78).

DISCUSSION

An impaired sense of smell may serve as a readily accessible early marker of neurodegeneration and improve upon the prevailing delayed diagnoses and underascertainment of MCI/dementia.

Olfactory perception in children

The ability to smell is important for protection from danger and quality of life, even in children. Although smell loss is rare in children, it can be indicative of some childhood disorders and may be useful for understanding some disorders. This paper reviews the methods and results of behavioral testing olfaction in children, with an emphasis on odor identification, the most common method of assessing the sense of smell in both children and adults. The Pediatric Smell Wheel® is described as a relatively new and powerful tool for testing olfaction in children as young as 4 years of age. An example of its use in testing children with a childhood disorders (autism spectrum disorder, ASD) is provided in addition to a review of the literature on smell function in ASD. It is possible to reliably test sense of smell in children as young as 4 years old and many studies have shown that performance improves with age and can be impacted by childhood disorders. Sex differences in children are briefly discussed. Finally, the paper suggests other methods of testing olfaction in children, such as odor discrimination, that depend less on cognitive factors, which may enhance our understanding of the olfactory capabilities of young children.

Initiation of the age-related decline of odor identification in humans: A meta-analysis

BACKGROUND

Aging is an important contributor to olfactory system deterioration in humans, leading to increased health and safety risks as well as affecting the quality of life. However, it is currently unknown when age-related olfactory deterioration begins in humans and thus when to initiate interventions to prevent or slow it.

OBJECTIVE

To determine the decade in which olfactory function begins to deteriorate in healthy humans by determining when odor identification is first impaired.

DATA SOURCE AND STUDY SELECTION

Studies cited in the PubMed database were searched from its inception to March 2017 using the terms "olfac*" or "smell" and "ag*". The effect size of each comparison was calculated.

RESULTS

In this meta-analysis, the effect sizes as determined using Cohen's d for the comparisons between 30 and 39.9- and 40-49.9-year-olds was 0.06 (95% CI: -0.17 to 0.29), between 40-49.9-year-olds was 0.62 (95% CI: 0.20-1.04), considered a medium effect size, and between 35-55-year-olds and those >55years old was 1.12 (95% CI: 1.06-1.45), considered a very large effect.

CONCLUSION

Olfactory function deterioration, as determined by an impaired ability to identify odors, starts in the fifth decade of life in healthy humans.

Olfactory dysfunction in behavioral variant frontotemporal dementia

OBJECTIVE

Several neurodegenerative disorders show olfactory dysfunction. In patients with frontotemporal dementia (FTD), olfactory impairment is probably due to the involvement of the temporal and orbitofrontal lobes. We hypothesized that due to the disrupted areas in FTD, there would be an impairment in smell identification, differentiation and association. Moreover, we hypothesized that there would be a correlation between the severity of FTD and the severity of odor dysfunction.

METHODS

In the current study, we compared odor identification, discrimination and association of nine patients with behavioral variant FTD with eleven healthy controls using the Brief Smell Identification Test and the Odor Perception and Semantics Battery.

RESULTS

The results showed significant differences in the odor association test, but not in the identification or discrimination test. There was no correlation between disease severity and the performance in the odor tests.

CONCLUSION

We showed impairment of odor association that is most likely due to disruption of specific associative areas involved in olfactory processing. Specifically, we propose that the impairment may well be due to disrupted areas in the temporal lobe and amygdala.

Effects of nutritional status and cognitive ability on olfactory function in geriatric patients

OBJECTIVE

The aim of this study was to investigate the prevalence of olfactory dysfunction and evaluate the relationship between olfactory function and nutritional status, comorbidity, and the results of a neurocognitive test in geriatric patients who do not suffer from neurodegenerative disease.

MATERIALS AND METHODS

A total of 45 patients who visited the Geriatric Health Center of Chungnam National University Hospital were enrolled in this study. Olfactory function was assessed using a Korean Version of Sniffin' Stick Test II. Cognitive status of all participants was assessed with the MMSE-K (Korean version of the Mini-Mental State Examination). Nutritional status was assessed with body mass index, Mini-Nutritional Assessment (MNA), and serum total protein and albumin.

RESULTS

A total of 45 participants were enrolled in this study. Of these subjects, 28 were men and 17 were women, with a mean age of 71.7±5.16 years. Nine (20%) were normosmia, 13 (28.9%) were hyposmia, and 23 (51.1%) were anosmia. Thirty-six patients (80%) suffered from olfactory dysfunction (anosmia or hyposmia). MMSE score showed significant correlation with MNA score. There were significant negative correlations between age and total TDI (threshold, discrimination, and identification) score, discrimination score, identification score, and MMSE score. MMSE score showed significant correlation with discrimination score and identification score. However, MNA score did not show any significant correlation with olfactory function test results.

CONCLUSION

Although olfactory function was not influenced by nutritional status, abilities of discrimination and identification of odors were associated with cognitive function in geriatric patients.

An odor identification approach based on event-related pupil dilation and gaze focus

Olfactory disorders constitute a potential marker of many diseases and are considered valuable clues to the diagnosis and evaluation of progression for many disorders. The most commonly used test for the evaluation of impairments of olfactory identification requires the active participation of the subject, who must select the correct name of the perceived odor from a list. An alternative method is required because speech may be impaired or not yet learned in many patients. As odor identification is known to be facilitated by searching for visual clues, we aimed to develop an objective, vision-based approach for the evaluation of odor identification. We used an eye tracking method to quantify pupillary and ocular responses during the simultaneous presentation of olfactory and visual stimuli, in 39 healthy participants aged from 19 to 77years. Odor presentation triggered an increase in pupil dilation and gaze focus on the picture corresponding to the odor presented. These results suggest that odorant stimuli increase recruitment of the sympathetic system (as demonstrated by the reactivity of the pupil) and draw attention to the visual clue. These results validate the objectivity of this method.

Olfactory function in Wave 2 of the National Social Life, Health, and Aging Project

OBJECTIVE

To investigate the sense of smell, including sensitivity and odor identification, and characterize the U.S. national prevalence of olfactory dysfunction in older adults, thereby facilitating further investigation of the substantial risks for older adults associated with this basic sensory ability.

METHOD

The sense of smell was evaluated using the Olfactory Function Field Exam (OFFE), a measure designed specifically for field research, which assesses 3 components of olfaction: sensitivity to n-butanol (a standard testing odorant) and androstadienone (AND, a key social odor produced by humans), as well as the ability to identify odors. Respondents were randomly selected from the National Social Life, Health, and Aging Project Wave 2 sample to receive the OFFE (n = 2,304), and 2,212 consented to participate.

RESULTS

In the U.S. population aged 62-90, n-butanol detection ability was significantly worse at older ages (ordinal logistic regression, p < .001); however, there was no difference in detection ability between genders (p = .60). AND detection ability was also significantly worse at older ages (p = .003), but in contrast to n-butanol, women outperformed men (p = .001). As expected, odor identification ability was worse in older people than in younger (p < .001), and women were more accurate than men (p = .001).

DISCUSSION

We report for the first time 3 facets of olfactory function and its association with age and gender in a representative sample of U.S. older adults. Future analyses of these data are needed to elucidate the sense of smell's role in physical, social, and mental health with aging.

Sensitivity and Specificity of Self-Reported Olfactory Function in a Home-Based Study of Independent-Living, Healthy Older Women

INTRODUCTION

The 2011-14 US National Health and Nutrition Examination Survey chemosensory protocol asks adults to self-rate their orthonasal (via nostrils) and retronasal (via mouth) smell abilities for subsequent odor identification testing. From data collected with a similar protocol, we aimed to identify a self-reported olfactory index that showed the best sensitivity (correctly identifying dysfunction) and specificity (correctly indentifying normosmia) with measured olfaction.

METHODS

In home-based testing, 121 independent-living older women (age 73±7 years) reported their olfactory function by interviewer-administered survey. Olfactory function was measured orthonasally via composite (odor threshold, identification task) or identification task alone.

RESULTS

Only 16 % of women self-rated "below average" smell function. More women perceived loss of smell (38 %) or flavor (30 %) with aging. The rate of measured dysfunction was 30 % by composite (threshold and identification) and 21.5 % by identification task, the latter misclassifying some mild dysfunction as normosmia. An index of self-rated smell function and perceived loss yielded the most favorable sensitivity (65 %) and specificity (77 %) to measured function. Self-rated olfaction showed better agreement with severe measured dysfunction; mild dysfunction was less noticed.

CONCLUSIONS

Self-reported indices that query about current and perceived changes in smell and flavor with aging showed better sensitivity estimates than those previously reported. Specificity was somewhat lower-some older adults may correctly perceive loss unidentified in a single assessment, or have a retronasal impairment that was undetected by an orthonasal measure.

IMPLICATIONS

Our findings should inform self-rated measures that screen for severe olfactory dysfunction in clinical/community settings where testing is not routine.

How olfactory acuity affects the sensory assessment of boar fat: a proposal for quantification

Due to animal welfare concerns the production of entire male pigs is one viable alternative to surgical castration. Elevated levels of boar taint may, however, impair consumer acceptance. Due to the lack of technical methods, control of boar taint is currently done using sensory quality control. While the need for control measures with respect to boar taint has been clearly stated in EU legislation, no specific requirements for selecting assessors have yet been documented. This study proposes tests for the psychophysical evaluation of olfactory acuity to key volatiles contributing to boar taint. Odor detection thresholds for androstenone and skatole are assessed as well as the subject's ability to identify odorants at various levels through easy-to-use paper smell strips. Subsequently, fat samples are rated by the assessors, and the accuracy of boar taint evaluation is studied. Considerable variation of olfactory performance is observed demonstrating the need for objective criteria to select assessors.

Neurofunctional dopaminergic impairment in elderly after lifetime exposure to manganese

BACKGROUND

Manganese (Mn) is an essential element that can become neurotoxic through various exposure windows over the lifespan. While there is clear evidence of Mn neurotoxicity in pediatric and adult occupational populations, little is known about effects in the elderly who may exhibit enhanced susceptibilities due to compromised physiology compared to younger adults. In the province of Brescia, Italy, the Valcamonica area has been the site of three ferroalloy plants operating from 1902 to 2001. Metal emissions of Mn and to a lesser extent lead (Pb) have impacted the surrounding environment, where a high prevalence of Parkinsonism was previously observed. This study aimed to assess neurocognitive and motor functions in healthy elderly subjects residing for most of their lifetime in Valcamonica or in a reference area unimpacted by ferroalloy plant activity.

METHODS

Subjects were enrolled for extensive neurobehavioral assessment of motor, cognitive and sensory functions. Exposure was assessed with 24h personal air sampling for PM10 airborne particles, surface soil and tap water measurement at individual households, Mn levels in blood and urine and Pb in blood. Dose-response relationships between exposure indicators and biomarkers and health outcomes were analyzed with generalized (linear and logistic) additive models (GAM).

RESULTS

A total of 255 subjects (55% women) were examined; most (52.9%) were within the 65-70 years age class. Average airborne Mn was 26.41 ng/m(3) (median 18.42) in Valcamonica and 20.96 ng/m(3) (median 17.62) in the reference area. Average Mn in surface soil was 1026 ppm (median 923) in Valcamonica and 421 ppm (median 410) in the reference area. Manganese in drinking water was below the LDL of 1 μg/L. The GAM analysis showed significant association between airborne Mn (p=0.0237) and the motor coordination tests of the Luria Nebraska Neuropsychological Battery. The calculation of the Benchmark Dose using this dose-response relationship yielded a lower level confidence interval of 22.7 ng/m(3) (median 26.4). For the odor identification score of the Sniffin Stick test, an association was observed with soil Mn (p=0.0006) and with a significant interaction with blood Pb (p=0.0856). Significant dose-responses resulted also for the Raven's Colored Progressive Matrices with the distance from exposure point source (p=0.0025) and Mn in soil (p=0.09), and for the Trail Making test, with urinary Mn (p=0.0074). Serum prolactin (PRL) levels were associated with air (p=0.061) and urinary (p=0.003) Mn, and with blood Pb (p=0.0303). In most of these associations age played a significant role as an effect modifier.

CONCLUSION

Lifelong exposure to Mn was significantly associated with changes in odor discrimination, motor coordination, cognitive abilities and serum PRL levels. These effects are consistent with the hypothesis of a specific mechanism of toxicity of Mn on the dopaminergic system. Lead co-exposure, even at very low levels, can further enhance Mn toxicity.

Connecticut (CCCRC) Olfactory Test: Normative Values in 426 Healthy Volunteers

Application of Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory test to healthy Turkish volunteers, obtain normative data set and analyse the role of age, sex and smoking on olfactory scores. The present study was conducted at Bezmialem Vakif University, Department of Otorhinolaryngology. Total of 426 healthy volunteers were subjected to CCCRC olfactory test which consists of n-butanol smell threshold test and smell identification test. Olfactory function score was assessed (0: worst score; 7: best score) and mean scores were calculated. Mean age was (36.7 ± 11.1; range, 17-68). 46.2 % of the subjects were male and 53.8 % were female; 37.1 % were smokers and 62.9 % were non-smokers. Mean n-butanol threshold score was 6.36 out of 7, mean identification score was 6.34 and mean total score was 6.35. According to CCCRC score: there were no anosmic individuals, 0.5 % were severely hyposmic, 2.6 % were moderately hyposmic,15.3 % were mildly hyposmic and 81.6 % were normosmic. CCCRC olfactory test is cost-effective, simple and practical. It can be easily applied in clinical settings. The CCCRC olfactory test is appropriate for assessment of olfactory function: Turkish population is familiar in terms of the odors used in CCCRC test. The power of this study is that it provides a normative data set against which many factors can be compared.