521 - The link between olfactory dysfunction and dementia: the road so far.

Dementia is characterized by the presence of progressive cognitive impairment losses in the individual’s social and occupational activities. Its etiological diagnosis has therapeutic and prognostic implications. Although its definitive diagnosis depends on neuropathological analysis, detailed anamnesis, physical and neuropsychological tests; biochemical and neuroimaging exams may enable a greater accuracy. Technological innovations using structural and functional neuroimaging methods, as well as biology and molecular genetics techniques, have presented perspectives for the early diagnosis of dementias, particularly Alzheimer’s disease (AD). However, such techniques burden the diagnostic investigation, making its practice unfeasible most the times. The probable link between neurodegenerative diseases and impaired olfactory dysfunction has long been studied. It is suggested that smell tests can be used in dementia’s early detection and differential diagnosis, reducing costs and facilitating the establishment of appropriate treatment. In order to verify the validity of this information, a medical literature search was carried out in may 2021 using PubMed and Cochrane Library, including the terms “olfaction” and “olfactory dysfunction” combined individually with “neurodegenerative disorder”, “dementia” and “Alzheimer’s disease”. Only systematic reviews and meta-analyses written in English from 1991 to 2021 were included. Results show that olfactory impairment in neurodegenerative diseases worsens progressively as patients progress from mild cognitive impairment to AD. It suggests that odor tests could potentially identify AD in the preclinical stages. Although, rigorously designed longitudinal cohort studies are necessary to clarify the value of olfactory identification testing in predicting the onset of AD and its value as an early marker of cognitive decline. In addition, AD patients are more impaired on odor identification and recognition tasks and Parkinson’s Disease (PD) patients on odor detection thresholds tasks, what suggests that PD patients are more impaired on low-level perceptual olfactory tasks whereas AD patients are more strongly impaired on higher-order olfactory tasks involving specific cognitive processes. The results suggest smell tests are a cheaper, simpler to apply and a promising weapon for detecting individuals at risk of dementia.

Discordance Between Subjective and Objective Measures of Smell and Taste in US Adults

Objective Examine the rates and factors associated with under- and overreporting of subjective changes in smell or taste as compared with objective measures. Study Design Cross-sectional analysis. Setting National Health and Nutrition Examination Survey (2013-2014). Methods We examined participants ≥40 years old who completed subjective questionnaires (smell, n = 3510; taste, n = 3089), validated objective 8-odor pocket smell tests, and NaCl/quinine taste tests. Over- and underreporting was determined by the difference in subjective and objective results. Univariate and multivariate logistic regression analyses incorporated sampling weights. Results A majority of participants correctly classified impairment: smell (73.7%; 95% CI, 71.2%-76.1%) and taste (78.3%; 95% CI, 75.6%-80.7%). Age ≥65 years (odds ratio, 2.23; P = .001) was associated with underreporting impairment, and persistent cold symptoms (odds ratio, 2.15; P = .001) were associated with overreporting smell impairment. Smoke, onion, and natural gas scents were incorrectly identified more frequently by individuals aged ≥65 years after Bonferroni correction. No factors were associated with under- and overreporting taste impairment. Conclusion Although the concordance rate between subjective and objective assessment of smell and taste impairment remains high, we found that older age was associated with incorrect report of impairment. This suggests that the subjective perception of smell varies across demographical and clinical factors, and it is important to not overlook such factors in clinical practice. Potentially using a simplified odor assessment regularly in the clinical setting may aid in early detection and intervention.

Interviewer Effects in Biosocial Survey Measurements

Increasingly surveys are using interviewers to collect objective health measures, also known as biomeasures, to replace or supplement traditional self-reported health measures. However, the extent to which interviewers affect the (im)precision of biomeasurements is largely unknown. This article investigates interviewer effects on several biomeasures collected in three waves of the National Social Life, Health, and Aging Project (NSHAP). Overall, we find low levels of interviewer effects, on average. This nevertheless hides important variation with touch sensory tests being especially high with 30% interviewer variation, and smell tests and timed balance/walk/chair stands having moderate interviewer variation of around 10%. Accounting for contextual variables that potentially interact with interviewer performance, including housing unit type and presence of a third person, failed to explain the interviewer variation. A discussion of these findings, their potential causes, and their implications for survey practice is provided.

Diagnosis of Anosmia and Hyposmia: A Systematic Review

Background Anosmia and hyposmia have many etiologies, including trauma, chronic sinusitis, neoplasms, and respiratory viral infections such as rhinovirus and SARS-CoV-2. We aimed to systematically review the literature on the diagnostic evaluation of anosmia/hyposmia. Methods PubMed, EMBASE, and Cochrane databases were searched for articles published since January 1990 using terms combined with Medical Subject Headings (MeSH). We included articles evaluating diagnostic modalities for anosmia, written in the English language, used original data, and had two or more patients. Results A total of 2065 unique titles were returned upon the initial search. Of these, 226 abstracts were examined, yielding 27 full-text articles meeting inclusion criteria (Level of evidence ranging from 1 to 4; most level 2). The studies included a total of 13,577 patients. The most utilized diagnostic tools were orthonasal smell tests (such as the Sniffin’ Sticks and the UPSIT, along with validated abridged smell tests). Though various imaging modalities (including MRI and CT) were frequently mentioned in the workup of olfactory dysfunction, routine imaging was not used to primarily diagnose smell loss. Conclusion The literature includes several studies on validity and reliability for various smell tests in diagnosing anosmia. Along with a thorough history and physical, validated orthonasal smell tests should be part of the workup of the patient with suspected olfactory dysfunction. The most widely studied modality was MRI, but criteria for the timing and sequence of imaging modalities was heterogenous.

Impact of Exercise Timing on Chemosensory Response, Appetite, and Energy Intake in Lean Males

Background: High-intensity exercise can have an anorectic impact, leading to negative energy balance. Several studies have reported that the practice of physical activity could also cause a shift in perceptions and preferences, causing a change in food intakes. Objective: This study aimed to question to what extent the timing of exercise in relation to a meal could have an impact on olfaction and gustation, appetite, and food choices. Methods: Twelve males aged 25 (4) years with a body mass index of 22.4 (2.0) kg/m2 attended two experimental visits in a counterbalanced fashion. The participants consumed a standardized breakfast between 7:00 and 7:30 a.m. and were subjected to smell and taste tests upon arrival at the laboratory (8:30 a.m.). In the EX9:40 visit, the participants performed a 30-min exercise session (70% of maximum oxygen uptake) at 9:40 a.m., followed by a 90-min sedentary break. In EX10:30, the participants first took part in the 90-min sedentary break and then performed the 30-min exercise session at 10:30 a.m. Taste and smell tests were performed again at 11:40 a.m., immediately followed by an ad libitum buffet-style meal. Visual analog scales were used to report appetite sensations during the session and satiety quotients around the lunch. Results: There was no difference in energy intakes between the EX9:40 (596 [302] kcal) and EX10:30 (682 [263] kcal) conditions (p = .459). There was no condition effect for the taste and smell sensations (all ps > .05), appetite sensation, or satiety quotients around the meal (all ps > .05). Conclusion: Exercise timing in the morning had no effect on taste and smell perceptions, appetite sensations, or energy intakes.

Screening performance of abbreviated versions of the UPSIT smell test

ABSTRACTBackgroundHyposmia features in several neurodegenerative conditions, including Parkinson’s disease (PD). The University of Pennsylvania Smell Identification Test (UPSIT) is a widely used screening tool for detecting hyposmia, but is time-consuming and expensive when used on a large scale.MethodsWe assessed shorter subsets of UPSIT items for their ability to detect hyposmia in 891 healthy participants from the PREDICT-PD study. Established shorter tests included Versions A and B of both the 4-item Pocket Smell Test (PST) and 12-item Brief Smell Identification Test (BSIT). Using a data-driven approach, we evaluated screening performances of 23,231,378 combinations of 1-7 smell items from the full UPSIT.ResultsPST Versions A and B achieved sensitivity/specificity of 76.8%/64.9% and 86.6%/45.9% respectively, whilst BSIT Versions A and B achieved 83.1%/79.5% and 96.5%/51.8% for detecting hyposmia defined by the longer UPSIT. From the data-driven analysis, two optimised sets of 7 smells surpassed the screening performance of the 12 item BSITs (with validation sensitivity/specificities of 88.2%/85.4% and 100%/53.5%). A set of 4 smells (Menthol, Clove, Gingerbread and Orange) had higher sensitivity for hyposmia than PST-A, -B and even BSIT-A (with validation sensitivity 91.2%). The same 4 smells also featured amongst those most commonly misidentified by 44 individuals with PD compared to 891 PREDICT-PD controls and a screening test using these 4 smells would have identified all hyposmic patients with PD.ConclusionUsing abbreviated smell tests could provide a cost-effective means of screening for hyposmia in large cohorts, allowing more targeted administration of the UPSIT or similar smell tests.

Scents and Sensibility: Olfaction, Sense-Making, and Meaning Attribution

How are smells invested with meaning and how do those meanings structure interactions and group relations? I use cultural theories of meaning-making to explore these questions, situating my inquiry in the world of commercially marketed perfumes. Using blind smell tests in focus groups, I examine how individuals make sense of certain fragrances absent direction from manufacturers or marketing materials. I find that most participants can correctly decode perfume manufacturers’ intended message, target users, and usage sites. I unpack the role of culture in these initial classifications of smells, and later, in how participants apply those evaluations to reify social boundaries and reproduce social relations—especially with reference to race and class. I also identify two cognitive mechanisms—embodied simulation and iterative reprocessing—illustrating how these mechanisms facilitate a dynamic interaction between practical and discursive modes of consciousness in deciphering smells. Finally, I elaborate the role of sociocultural location in olfactory meaning-making. People in all locations may be familiar with public olfactory codes, but social position influences how participants think about, interpret, and apply those codes in meaning-making.