Barriers and Facilitators of Self-Management in Older People with Type 1 Diabetes: A Narrative Review Focusing on Cognitive Impairment

Over the past decades, life expectancy of people with type 1 diabetes has increased considerably, which brings potential challenges due to the process of aging. Cognitive aging and dementia, as well as reductions in visual acuity, hearing and dexterity, can influence the frequency and quality of daily self-management activities, including medication taking and insulin dosing, glucose self-monitoring, and healthy eating. This can increase the risk for hypo- and hyperglycemic events, which, in turn, may contribute to cognitive decline. Because there is a gap in understanding the barriers and facilitators of self-management in older adults with type 1 diabetes and the relationship to cognitive functioning, the authors 1) review the available literature on cognitive aging and type 1 diabetes, 2) describe what self-management in later adulthood entails and the cognitive functions required for effective self-management behaviors, 3) analyze the interaction between type 1 diabetes, cognition, aging, and self-management behaviors, and 4) describe the barriers and facilitators for self-management throughout the life span and how they may differ for older people. Potential evidence-based practices that could be developed for older adults with type 1 diabetes are discussed. There is need for further studies that clarify the impact of aging on T1D self-management, ultimately to improve diabetes care and quality of life.

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.

CONCLUSION

Memory function may be associated with olfactory impairment in older adults.

Tactile discrimination as a diagnostic indicator of cognitive decline in patients with mild cognitive impairment: A narrative review

Background

Tactile discrimination, a cognitive task reliant on fingertip touch for stimulus discrimination, encompasses the somatosensory system and working memory, with its acuity diminishing with advancing age. Presently, the evaluation of cognitive capacity to differentiate between individuals with early Alzheimer's disease (AD) and typical older adults predominantly relies on visual or auditory tasks, yet the efficacy of discrimination remains constrained.

Aims

To review the existing tactile cognitive tasks and explore the interaction between tactile perception and the pathological process of Alzheimer's disease. The tactile discrimination task may be used as a reference index of cognitive decline in patients with mild cognitive impairment and provide a new method for clinical evaluation.

Methods

We searched four databases (Embase, PubMed, Web of Science and Google scholar). The reference coverage was from 1936 to 2023. The search terms included "Alzheimer disease" "mild cognitive impairment" "tactile" "tactile discrimination" "tactile test" and so on. Reviews and experimental reports in the field were examined and the effectiveness of different types of tactile tasks was compared.

Main results

Individuals in the initial phases of Alzheimer's spectrum disease, specifically those in the stage of mild cognitive impairment (MCI), exhibit notable impairments in tasks involving tactile discrimination. These tasks possess certain merits, such as their quick and straightforward comparability, independence from educational background, and ability to circumvent the limitations associated with conventional cognitive assessment scales. Furthermore, tactile discrimination tasks offer enhanced accuracy compared to cognitive tasks that employ visual or auditory stimuli.

Conclusions

Tactile discrimination has the potential to serve as an innovative reference indicator for the swift diagnosis of clinical MCI patients, thereby assisting in the screening process on a clinical scale.

A Comprehensive Review of COVID-19-Related Olfactory Deficiency: Unraveling Associations with Neurocognitive Disorders and Magnetic Resonance Imaging Findings

Olfactory dysfunction (OD) is one of the most common symptoms in COVID-19 patients and can impact patients' lives significantly. The aim of this review was to investigate the multifaceted impact of COVID-19 on the olfactory system and to provide an overview of magnetic resonance (MRI) findings and neurocognitive disorders in patients with COVID-19-related OD. Extensive searches were conducted across PubMed, Scopus, and Google Scholar until 5 December 2023. The included articles were 12 observational studies and 1 case report that assess structural changes in olfactory structures, highlighted through MRI, and 10 studies correlating the loss of smell with neurocognitive disorders or mood disorders in COVID-19 patients. MRI findings consistently indicate volumetric abnormalities, altered signal intensity of olfactory bulbs (OBs), and anomalies in the olfactory cortex among COVID-19 patients with persistent OD. The correlation between OD and neurocognitive deficits reveals associations with cognitive impairment, memory deficits, and persistent depressive symptoms. Treatment approaches, including olfactory training and pharmacological interventions, are discussed, emphasizing the need for sustained therapeutic interventions. This review points out several limitations in the current literature while exploring the intricate effects of COVID-19 on OD and its connection to cognitive deficits and mood disorders. The lack of objective olfactory measurements in some studies and potential validity issues in self-reports emphasize the need for cautious interpretation. Our research highlights the critical need for extensive studies with larger samples, proper controls, and objective measurements to deepen our understanding of COVID-19's long-term effects on neurological and olfactory dysfunctions.

The Association of Allergy-Related and Non-Allergy-Related Olfactory Impairment with Cognitive Function in Older Adults: Two Cross- Sectional Studies

BACKGROUND

Evidence on the association of Olfactory Impairment (OI) with age-related cognitive decline is inconclusive, and the potential influence of allergy remains unclear.

OBJECTIVE

We aimed to evaluate the cross-sectional associations of allergy-related and non-allergy- related OI to cognitive function.

METHODS

We included 2,499 participants from the Health and Retirement Study (HRS)-Harmonized Cognitive Assessment Protocol (HCAP) sub-study and 1,086 participants from the English Longitudinal Study of Ageing (ELSA)-HCAP. The Olfactory Function Field Exam (OFFE) using Sniffin' Stick odor pens was used to objectively assess olfactory function and an olfactory score <6/11 indicated OI. Mini-Mental Status Examination (MMSE) was used to assess global cognitive function and define cognitive impairment (<24/30). A neuropsychologic battery was used to assess five cognitive domains.

RESULTS

Compared to non-OI participants, individuals with OI had lower MMSE z-score [βHRS = -0.33, 95% Confidence Interval (CI): -0.41 to -0.24; βELSA = -0.31, -0.43 to -0.18] and higher prevalence of cognitive impairment (Prevalence Ratio (PR)HRS = 1.46, 1.06 to 2.01; PRELSA = 1.63, 1.26 to 2.11). The associations were stronger for non-allergy-related OI (βHRS = -0.36; βELSA = -0.34) than for allergy-related OI (βHRS = -0.26; βELSA = 0.13). Similar associations were observed with domain- specific cognitive function measures.

CONCLUSION

OI, particularly non-allergy-related OI, was related to poorer cognitive function in older adults. Although the current cross-sectional study is subject to several limitations, such as reverse causality and residual confounding, the findings will provide insights into the OI-cognition association and enlighten future attention to non-allergy-related OI for the prevention of potential cognitive impairment.

Investigating the Link between Eating Attitudes, Taste and Odour Preferences and the Chemical Senses

OBJECTIVES

To examine if higher degrees of pathological eating attitudes in a non-clinical sample are associated with odour and taste perception and preferences based on psychophysical ratings.

PARTICIPANTS AND METHODS

A total of 80 female university students completed the eating attitudes test (EAT-26), followed by four chemosensory measures including olfactory and gustatory perception plus perceptual ratings and preferences for food odours and tastes.

RESULTS

There were no significant correlations between EAT-26 scores and measures of olfactory and gustatory perception. However, a significant interaction effect indicated higher degrees of pathological eating attitudes may be associated with differential sensitivity to sweet and fatty food odours compared to those with lower levels of pathological eating attitudes.

CONCLUSIONS

This was the first study to examine pathological eating attitudes using food stimuli with a non-clinical sample. The results remain preliminary until replication. However, the findings highlight the need for development of measures of disordered eating attitudes and behaviours that go beyond caloric restriction.

The association of gustatory dysfunction, olfactory dysfunction, and cognition in older adults

BACKGROUND

The association of gustatory dysfunction (GD) with quality of life (QOL) and cognition in older adults is understudied. Our objective was to study the prevalence of GD in the community and explore impacts and associated factors.

METHODS

A prospective, multi-institutional, pre-corona virus disease (COVID) cohort of adults aged 50 years and older had smell and taste testing using "Sniffin' Sticks" (TDI) and "Taste Strips." The impact of GD on mood, QOL, and social interaction was assessed through visual analog scales. Subjects completed the Questionnaire of Olfactory Disorders, Patient Health Questionnaire 9, Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and the DeJong scale of loneliness.

RESULTS

A total of 48 patients, average age of 54.7 years, were enrolled. Thirty-two percent experienced GD on taste strips, and 62% experienced olfactory dysfunction (OD) on TDI. Almost 30% (29.5%) had both GD and OD. GD and OD correlated with worsened cognitive function on MMSE (r = 0.392 and 0.05, p = 0.018 and 0.003). Subjects with both GD and OD had worse MMSE than either alone (p = 0.003). Dry mouth and difficult chewing correlated with GD (r = -0.37 and -0.31, p = 0.10 and 0.37). Self-reported GD and OD were correlated (r = 0.46, p = 0.001), as were psychophysical GD and OD (r = 0.394, p = 0.008). GD did not correlate with other metrics.

CONCLUSION

Thirty-two percent of subjects experienced GD on psychophysical testing, yet most are unaware without impacts on daily life. However, GD correlates with worsened cognitive function. Taste testing may play a role in screening of neurocognitive decline, and multisensory dysfunction may indicate of worsened cognitive states.

Cerebral abnormalities in HIV-infected individuals with neurocognitive impairment revealed by fMRI

Although the combination antiretroviral treatment (cART) has considerably lowered the risk of HIV associated dementia (HAD), the incidence of neurocognitive impairments (NCI) has not decreased likely due to the insidious and slow progressive nature of HIV infection. Recent studies showed that the resting-state functional magnetic resonance imaging (rs-fMRI) is a prominent technique in helping the non-invasive analysis of neucognitive impairment. Our study is to explore the neuroimaging characteristics among people living with HIV (PLWH) with or without NCI in terms of cerebral regional and neural network by rs-fMRI, based on the hypothesis that HIV patients with and without NCI have independent brain imaging characteristics. 33 PLWH with NCI and 33 PLWH without NCI, recruited from the Cohort of HIV-infected associated Chronic Diseases and Health Outcomes, Shanghai, China (CHCDO) which was established in 2018, were categorized into the HIV-NCI and HIV-control groups, respectively, based on Mini-Mental State Examination (MMSE) results. The two groups were matched in terms of sex, education and age. Resting-state fMRI data were collected from all participants to analyze the fraction amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) to assess regional and neural network alterations in the brain. Correlations between fALFF/FC values in specific brain regions and clinical characteristics were also examined. The results showed increased fALFF values in the bilateral calcarine gyrus, bilateral superior occipital gyrus, left middle occipital gyrus, and left cuneus in the HIV-NCI group compared to the HIV-control group. Additionally, increased FC values were observed between the right superior occipital gyrus and right olfactory cortex, bilateral gyrus rectus, and right orbital part of the middle frontal gyrus in the HIV-NCI group. Conversely, decreased FC values were found between the left hippocampus and bilateral medial prefrontal gyrus, as well as bilateral superior frontal gyrus. The study concluded that abnormal spontaneous activity in PLWH with NCI primarily occurred in the occipital cortex, while defects in brain networks were mostly associated with the prefrontal cortex. The observed changes in fALFF and FC in specific brain regions provide visual evidence to enhance our understanding of the central mechanisms underlying the development of cognitive impairment in HIV patients.

Gustatory dysfunction perceptions versus objective gustatory dysfunction among older adults

BACKGROUND

Research on gustatory dysfunction among older adults has been scarce relative to research on olfactory dysfunction, and the relationship between subjective and objective gustatory dysfunction has not been studied in detail. We aimed to evaluate whether subjective recognition of gustatory dysfunction correlates with objective diagnosis of gustatory dysfunction among older adults.

METHODS

In this retrospective, cross-sectional study, we reviewed the medical records of 138 patients of ages ≥ 60 years for whom data were available on self-reported and objectively measured gustatory and olfactory function from January 2018 through April 2021 at a specialized smell/taste center of a single institution. We reviewed self-reported and measured outcomes of gustatory and olfactory function using patient data including clinical characteristics, including age, sex, smoking history, and medical history.

RESULTS

We found that the subjective recognition of gustatory dysfunction does not correlate with the objective diagnosis of gustatory dysfunction based on the measured results of gustatory function tests. Subjective gustatory dysfunction, however, was correlated with subjective olfactory dysfunction. Among clinical and demographic characteristics, age and sex were significantly associated with measured gustatory function outcomes.

CONCLUSION

We suggest that subjective gustatory dysfunction underestimates objective dysfunction and recommend that older men with diminished olfactory function undergo gustatory function testing regardless of their self-reported gustatory function status.

Association Between Olfactory Dysfunction and Cognitive Impairment in Dementia-Free Older Adults: A Prospective Cohort Study in Taiwan

BACKGROUND

Previous studies assessing olfactory function and cognition have mostly been cross-sectional, and few have investigated the Asian geriatric population.

OBJECTIVE

To examine the relationships of olfaction with global or domain-specific cognitive function in Taiwanese community-dwelling older adults.

METHODS

This cohort study (2015-2019) is part of the Taiwan Initiative for Geriatric Epidemiological Research. The Taiwanese version of the Montreal Cognitive Assessment (MoCA-T) and a battery of neuropsychological tests were assessed at baseline and at a two-year follow-up. The cross-culture modified Sniffin' Sticks Identification Test (SSIT) was utilized to measure olfactory function. Generalized linear mixed models were used to examine the association of olfaction with cognitive performance over two years.

RESULTS

Data were collected from 376 participants (55.1% women), with a mean age of 75.6 years. A one-point decrease in the SSIT score (worsening of olfaction) was associated with worse global cognition (MoCA-T: βˆ= -0.13), memory (βˆ= -0.08 to -0.06), and verbal fluency (βˆ= -0.07). Compared with an SSIT score ≥ 11 (normosmia), an SSIT score < 8 (anosmia) was associated with worse global cognition (MoCA-T: βˆ= -0.99), memory (βˆ= -0.48 to -0.42), executive function (Trail Making Test A: βˆ= -0.36), attention (digit span backward: βˆ= -0.34), and verbal fluency (βˆ= -0.45). After stratified analyses, the associations remained in older adults ≥ 75 years, males, and non-carriers of apolipoprotein E ɛ4 in terms of global cognition, memory, and verbal fluency.

CONCLUSIONS

Odor identification deficits were associated with poor global or domain-specific cognitive function in a four-year cohort of community-dwelling older adults. Cognitive assessments should be conducted in dementia-free elderly individuals with impaired odor identification.

Olfactory and neurological outcomes of SARS-CoV-2 from acute infection to recovery

Educational objective

To investigate the impact of SARS-CoV-2 on sinonasal quality of life, olfaction, and cognition at different stages of viral infection and evaluate the association between olfaction and cognition in this population cohort.

Objectives

While olfactory dysfunction (OD) is a frequently reported symptom of COVID-19 (98% prevalence), neurocognitive symptoms are becoming more apparent as patients recover from infection. This study aims to address how different stages of infection [active infection (positive PCR test, symptomatic) vs. recovered (7 days post-symptoms)] compared to healthy control patients influence sinonasal quality of life, olfactory function, and cognition.

Study design

Prospective, longitudinal, case-control.

Methods

Participants completed the SNOT-22, University of Pennsylvania Smell Identification Test (UPSIT) and validated cognitive examinations to assess degree of smell loss and neurocognitive function at baseline and at 1 and 3 months for the active group and 3 months for the recovered group. Self-reported olfactory function and overall health metrics were also collected.

Results

The recovered group had the lowest average UPSIT score of 27.6 compared to 32.7 (active) and 32.6 (healthy control). 80% (n = 24) of the recovered patients and 56.3% (n = 9) of the active patients suffered from smell loss. In follow-up, the active group showed improvement in UPSIT scores while the recovered group scores worsened. In terms of neurocognitive performance, recovered patients had lower processing speed despite an improving UPSIT score.

Conclusion

SARS-CoV-2 infection was found to impact olfactory function in a delayed fashion with significant impact despite recovery from active infection. Although olfactory function improved, decrements in cognitive processing speed were detected in our cohort.

D2/D3 Receptor Agonism: Paving the Way for a New Therapeutic Target for Taste Disorders in Parkinson's Disease and Other Conditions?

Chemosensory (i.e., olfaction and taste) dysfunction is common in neurodegenerative (e.g., Parkinson's disease, Alzheimer's disease, and dementia), psychiatric (e.g., depression, bipolar disorders, other conditions), and postinfectious (i.e., long COVID) diseases and in the elderly. Despite its impact on patients' quality of life, no established treatment for taste disorders exists so far. A recent report on the effect of pramipexole, a D2/D3 agonist, on taste performance in healthy participants provides support for a new potential therapeutic target for taste dysfunction to be tested in future randomized, placebo-controlled, clinical trials across several populations reporting gustatory symptoms.

Olfaction and Executive Cognitive Performance: A Systematic Review

Objective tests of olfaction are widely available to aid in the assessment of olfaction. Their clearest role is in the characterization of olfactory changes, either reported by or suspected in a patient. There is a rapidly growing literature concerned with the association of olfactory changes with certain neuropsychiatric conditions and the use of olfactory testing to supplement conventional assessments in clinical and research practice is evolving. Neural pathways important for olfactory processing overlap extensively with pathways important for cognitive functioning, and especially those important for executive functioning, many of which are concentrated in the frontal lobes. Previous work has identified associations between performance on certain olfactory tests (most frequently olfactory identification) and executive functioning and behavioral measures (e.g. of impulsivity). More recently, similar associations have also been identified in non-clinical samples, raising new questions as to the utility of olfactory test scores as proxy measures for non-olfactory phenomena. In this systemic review, we sought to identify studies, both clinical and non-clinical, that investigated the associations of olfaction with performance on tasks sensitive to frontal lobe functioning. Our search criteria led to the identification of 70 studies published in English. We examined in detail and tabulated the data from these studies, highlighted each study's key findings, and critically evaluated these studies. We use the results of this review to reflect on some of the current and future challenges concerning the use of olfactory testing in clinical neuropsychiatric practice and research and speculate on the potential benefits of administering phonemic fluency in combination with olfactory testing to enhance its predictive value.

Gustatory event-related potential alterations in olfactory dysfunction patients

The phenomenon that longstanding impaired olfactory function is associated with the decreased gustatory function was described in present studies, which was seems attributed to mutual chemosensory interactions. And the interaction between olfaction and gustation still needs more research to figure out. The objective of the study was to investigate how the taste was influenced by olfactory impairment in the central pathway. We tested 33 subjects with normal (n = 19) or impaired (n = 14) olfactory function for their gustatory event-related potentials (gERPs). Validated tests were used for olfactory and gustatory testing (Sniffin’ Sticks, gERPs, and three-drop test). This study reported an objective gustatory function decline in olfactory dysfunction participants. However, it also reported the increased gustatory event-related potentials of olfactory dysfunction participants, especially at the frontal electrode (F_Z) and electrode 16 (E16), and the reduced latency of P2 peak of them at electrode 21 (E21), while no obvious difference was observed at the centro-parietal electrode (P_Z). Inferior insula might be the main response area for the increase in gERPs, and this increase averaged amplitude of the P2 component may attribute to compensation of the secondary gustatory response that occurred in the gustatory processing of olfactory-impaired patients.

Olfactory training for Olfactory dysfunction in COVID-19: A promising mitigation amidst looming neurocognitive sequelae of the pandemic

Olfactory dysfunction (OD) is a recognized symptom of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is independently associated with neurodegenerative disorders. Moreover, the central nervous system manifestations in patients infected with the coronavirus -2019 (COVID-19) have demonstrated cognitive decline and neuropsychiatric manifestations. Hence, OD in COVID -19 necessitates perusal of its' mechanism and available treatment options to avert possible development of neurocognitive sequelae of the pandemic. The article presents a literature review organized from the published information about olfactory training (OT) for OD during COVID-19. The methodology comprised retrieval of available literature from database searches and subsequent scrutinization of relevant information. Inferentially, Injury to the sustentacular cells, possessing angiotensin-converting enzyme 2 (ACE-2) receptors, is an important mechanism causing OD in COVID-19. OD may be prolonged in severe cases of anosmia predisposing to neurodegenerative and cognitive impairment in COVID-19 infection. OT demonstrates an effective treatment for OD based on human and animal-derived evidence through recent studies. It curtails the progression of OD, besides inducing neural rearrangement and changes in functional connectivity in patients receiving OT. Additionally, contemporary reports support that the administration of OT for COVID-induced anosmia is effective and encompasses no significant adverse effects. The present review highlights the prominence of olfactory training as a recommended intervention for OD in COVID-19. This review can guide the clinicians in curbing neurological repercussions of COVID besides enhancing cognitive rehabilitation through olfactory training.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Assessment of gustatory function in aging people using event-related potentials

Gustatory dysfunctions are more frequent than other chemosensory dysfunctions in aging people. Gustatory event-related potentials (ERPs) has been suggested as a reliable and effective approach for assessing gustatory functions in young and middle subjects, but has rarely been investigated in aging people, leaving influencing factors of ERPs in that population not completely understood. In this study, we analyzed gustatory ERPs results of aging participants and characterized potential impacting factors, including age, sex, BMI, drinking, smoking, hypertension, diabetes, cognition and psychophysical test scores of gustation and olfaction. Our results revealed three components (P1, N1 and P2) in gustatory ERPs upon salty stimulation. Significant differences between responses collected from different recording electrodes were observed: minimum latencies and maximum amplitudes of P1 were detected at frontal electrode, and maximum amplitudes of N1 and P2 were detected at central and centro-parietal electrodes, respectively. Major cortical sources of components P1, N1 and P2 were located at bilateral insula, frontal operculum, and orbitofrontal cortex. Diabetes was positively associated with latencies of P1. Sex was positively associated with amplitudes of P1, N1 and P2. Hypertension was negatively associated with amplitudes of P1 and P2. In conclusion, gustatory ERPs in aging people exhibited a specific topographical distribution, represented by sex-related differences and negative impacts of diabetes and hypertension.

Odor Sensitivity Versus Odor Identification in Older US Adults: Associations With Cognition, Age, Gender, and Race

The ability to identify odors predicts morbidity, mortality, and quality of life. It varies by age, gender, and race and is used in the vast majority of survey and clinical literature. However, odor identification relies heavily on cognition. Other facets of olfaction, such as odor sensitivity, have a smaller cognitive component. Whether odor sensitivity also varies by these factors has not been definitively answered. We analyzed data from the National Social Life, Health, and Aging Project, a nationally representative study of older US adults (n = 2081). Odor identification was measured using 5 validated odors presented with Sniffin' Stick pens as was odor sensitivity in a 6-dilution n-butanol constant stimuli detection test. Multivariate ordinal logistic regression modeled relationships between olfaction and age, gender, race, cognition, education, socioeconomic status, social network characteristics, and physical and mental health. Odor sensitivity was worse in older adults (P < 0.01), without gender (P = 0.56) or race (P = 0.79) differences. Odor identification was also worse in older adults, particularly men (both P ≤ 0.01), without differences by race. Decreased cognitive function was associated with worse odor identification (P ≤ 0.01) but this relationship was weaker for odor sensitivity (P = 0.02) in analyses that adjusted for other covariates. Odor sensitivity was less strongly correlated with cognitive ability than odor identification, confirming that it may be a more specific measure of peripheral olfactory processing. Investigators interested in associations between olfaction and health should consider both odor sensitivity and identification when attempting to understand underlying neurosensory mechanisms.

Exposure to Particulate Matter Air Pollution and Anosmia

IMPORTANCE

Anosmia, the loss of the sense of smell, has profound implications for patient safety, well-being, and quality of life, and it is a predictor of patient frailty and mortality. Exposure to air pollution may be an olfactory insult that contributes to the development of anosmia.

OBJECTIVE

To investigate the association between long-term exposure to particulate matter (PM) with an aerodynamic diameter of no more than 2.5 μm (PM2.5) with anosmia.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study examined individuals who presented from January 1, 2013, through December 31, 2016, at an academic medical center in Baltimore, Maryland. Case participants were diagnosed with anosmia by board-certified otolaryngologists. Control participants were selected using the nearest neighbor matching strategy for age, sex, race/ethnicity, and date of diagnosis. Data analysis was conducted from September 2020 to March 2021.

EXPOSURES

Ambient PM2.5 levels.

MAIN OUTCOMES AND MEASURES

Novel method to quantify ambient PM2.5 exposure levels in patients diagnosed with anosmia compared with matched control participants.

RESULTS

A total of 2690 patients were identified with a mean (SD) age of 55.3 (16.6) years. The case group included 538 patients with anosmia (20%), and the control group included 2152 matched control participants (80%). Most of the individuals in the case and control groups were women, White patients, had overweight (BMI 25 to <30), and did not smoke (women: 339 [63.0%] and 1355 [63.0%]; White patients: 318 [59.1%] and 1343 [62.4%]; had overweight: 179 [33.3%] and 653 [30.3%]; and did not smoke: 328 [61.0%] and 1248 [58.0%]). Mean (SD) exposure to PM2.5 was significantly higher in patients with anosmia compared with healthy control participants at 12-, 24-, 36-, 60-month time points: 10.2 (1.6) μg/m3 vs 9.9 (1.9) μg/m3; 10.5 (1.7) μg/m3 vs 10.2 (1.9) μg/m3; 10.8 (1.8) μg/m3 vs 10.4 (2.0) μg/m3; and 11.0 (1.8) μg/m3 vs 10.7 (2.1) μg/m3, respectively. There was an association between elevated PM2.5 exposure level and odds of anosmia in multivariate analyses that adjusted for age, sex, race/ethnicity, body mass index, alcohol or tobacco use, and medical comorbidities (12 mo: odds ratio [OR], 1.73; 95% CI, 1.28-2.33; 24 mo: OR, 1.72; 95% CI, 1.30-2.29; 36 mo: OR, 1.69; 95% CI, 1.30-2.19; and 60 mo: OR, 1.59; 95% CI, 1.22-2.08). The association between long-term exposure to PM2.5 and the odds of developing anosmia was nonlinear, as indicated by spline analysis. For example, for 12 months of exposure to PM2.5, the odds of developing anosmia at 6.0 µg/m3 was OR 0.79 (95% CI, 0.64-0.97); at 10.0 µg/m3, OR 1.42 (95% CI, 1.10-1.82); at 15.0 µg/m3, OR 2.03 (95% CI, 1.15-3.58).

CONCLUSIONS AND RELEVANCE

In this study, long-term airborne exposure to PM2.5 was associated with anosmia. Ambient PM2.5 represents a potentially ubiquitous and modifiable risk factor for the loss of sense of smell.

Hyposmia Is Associated with Reduced Cognitive Function in COVID-19: First Preliminary Results

BACKGROUND

Hyposmia is frequently reported as an initial symptom in coronavirus disease 2019 (COVID-19).

OBJECTIVE

As hyposmia accompanies cognitive impairment in several neurological disorders, we aimed to study whether hyposmia represents a clinical biomarker for both neurological involvement and cognitive impairment in mild CO-VID-19. We aimed to study whether olfactory dysfunction (OD) represents a clinical biomarker for both neurological involvement and cognitive impairment in mild COVID-19.

METHODS

Formal olfactory testing using the Sniffin'Sticks® Screening test, neuropsychological assessment using the Montreal Cognitive Assessment (MoCA), and detailed neurological examination were performed in 7 COVID-19 patients with mild disease course and no history of olfactory or cognitive impairment, and 7 controls matched for age, sex, and education. Controls were initially admitted to a dedicated COVID-19 screening ward but tested negative by real-time PCR.

RESULTS

The number of correctly identified odors was significantly lower in COVID-19 than in controls (6 ± 3, vs. 10 ± 1 p = 0.028, r = 0.58). Total MoCA score was significantly lower in COVID-19 patients than in controls (20 ± 5 vs. 26 ± 3, p = 0.042, r = 0.54). Cognitive performance indicated by MoCA was associated with number of correctly identified odors in COVID-19 patients and controls (COVID-19: p = 0.018, 95% CI = 9-19; controls: p = 0.18, r = 0.63, 95% CI = 13-18.5 r = 0.64).

DISCUSSION/CONCLUSION

OD is associated with cognitive impairment in controls and mild COVID-19. OD may represent a potentially useful clinical biomarker for subtle and even subclinical neurological involvement in severe acute respiratory distress syndrome coronavirus-2 infection.

The Association between Olfactory Function and Cognitive Impairment in Older Persons with Cognitive Impairments: A Cross-Sectional Study

Olfactory function is an emerging topic of research in the fields of cognitive impairment and neurodegenerative diseases. We aimed to confirm the association between olfactory function and cognitive impairment by assessing the olfactory function of older persons with cognitive impairment and identify whether olfactory function is associated with cognitive impairment. For this study, we recruited 117 older people aged ≥65 years with cognitive impairments from a public hospital in Korea. We used the Korean version of the expanded clinical dementia rating scale to evaluate participants’ cognitive impairments, and the University of Pennsylvania’s smell identification test to assess their olfactory function. Our results indicate a significant negative correlation between olfactory function and all domains of cognitive impairment (memory, orientation, judgement and problem-solving, community affairs, home and hobbies, and personal care). In addition, olfactory function was a factor associated with cognitive impairment in older persons. Therefore, we expect that our results to provide useful data for the development of interventions using olfactory stimulation to improve cognitive function in older persons with cognitive impairment.

The Importance of Complementary Collaboration of Researchers, Veterinarians, and Husbandry Staff in the Successful Training of Marmoset Behavioral Assays

Interest in marmosets as research models has seen exponential growth over the last decade, especially given that the research community is eager to improve on gaps with historical animal models for behavioral and cognitive disorders. The spectrum of human disease traits that present naturally in marmosets, as well as the range of analogous human behaviors that can be assessed in marmosets, makes them ideally suited as translational models for behavioral and cognitive disorders. Regardless of the specific research aims of any project, without close collaboration between researchers, veterinarians, and animal care staff, it would be impossible to meet these goals. Behavior is inherently variable, as are marmosets that are genetically and phenotypically diverse. Thus, to ensure rigor, reliability, and reproducibility in results, it is important that in the research environment, the animal's daily husbandry and veterinary needs are being met and align with the research goals while keeping the welfare of the animal the most critical and highest priority. Much of the information described herein provides details on key components for successful behavioral testing, based on a compendium of methods from peer-reviewed publications and our own experiences. Specific areas highlighted include habituation procedures, selection of appropriate rewards, optimization of testing environments, and ways to integrate regular veterinary and husbandry procedures into the research program with minimal disruptions to the behavioral testing plan. This article aims to provide a broad foundation for researchers new to establishing behavioral and cognitive testing paradigms in marmosets and especially for the veterinary and husbandry colleagues who are indispensable collaborators of these research projects.

Olfactory loss and aging: connections with health and well-being

Age-related olfactory dysfunction, or presbyosmia, is a common sensory impairment in aging adults. People in this demographic group with comorbid conditions or exposure to viral, traumatic, or environmental insults remain at the greatest risk for impairment. Several methods for assessing olfaction exist, but they are only available in special settings and require consideration of age, sex, ancestry, and cognition. Perhaps most importantly, olfactory dysfunction has been suggested as an early sign of Alzheimer's and Parkinson's disease and therefore may serve as a tool in the diagnosis and prognosis of these neurodegenerative conditions. Outside of this context, olfactory loss also impacts nutrition, safety, and social relationships, and even predicts mortality itself. This review covers the detection and manifestations of olfactory decline in aging individuals and the myriad ways in which olfactory impairment is connected to their health and well-being.

The association of frailty with olfactory and gustatory dysfunction in older adults: a nationally representative sample

BACKGROUND

Olfaction and gustation are associated with age-related decline. Deficits in these chemosenses have been associated with significant comorbidities. Meanwhile, frailty, defined as a reduced physiological reserve, is well correlated with mortality and worse health outcomes. We sought to analyze a nationally representative patient population to determine the association between chemosensory dysfunction and frailty.

METHODS

Cross-sectional analysis of U.S. National Health and Nutrition Examination Survey (NHANES) 2013-2014 was performed, using multivariate logistic regression to examine the association between chemosensory dysfunction and frailty in adults aged ≥40 years (n = 3547). Self-reported olfactory dysfunction (sOD) and gustatory dysfunction (sGD), and measured olfactory dysfunction (mOD) and gustatory dysfunction (mGD) were assessed for all participants. Frailty was operationalized using a 39-item frailty index (FI) and stratified into 4 groups using validated cutoffs.

RESULTS

Participants with sOD and mOD had significantly higher mean FI scores (sOD: 0.18 vs 0.13, p < 0.001; mOD: 0.20 vs 0.14, p < 0.001), whereas subjects with sGD, but not mGD, had higher mean FI scores (sGD: 0.21 vs 0.13, p < 0.001; mGD: 0.14 vs 0.14, p = 0.953). Multivariate logistic regression demonstrated frail participants had significantly greater odds of sGD (odds ratio [OR] 4.11; 95% confidence interval [CI], 3.46 to 4.88), sOD (OR 2.35; 95% CI, 1.98 to 2.78), and mOD (OR 1.58; 95% CI, 1.22 to 2.05), but not mGD (OR 1.21; 95% CI, 0.91 to 1.61). This association was strongest in the frailest group.

CONCLUSION

Self-reported chemosensory dysfunction and mOD are independently associated with measures of frailty, suggesting a novel method to assess or predict frailty.

Gustatory Dysfunction Is Closely Associated With Frailty in Patients With Chronic Kidney Disease

OBJECTIVE

Gustatory function is frequently impaired in patients with chronic kidney disease (CKD), and the associated taste dysfunction contributes to compromised nutrition. Whether gustatory dysfunction is an underappreciated risk factor for frailty in patients with CKD remains unclear. The objective of this work was to examine the role of gustatory dysfunction as a risk factor for frailty in patients with CKD.

METHODS

We prospectively enrolled patients with stage 3 or higher CKD from a single institute, with their gustatory function assessed using both objective (taste strip method) and subjective approaches, and frailty identified using the Edmonton frail scale, FRAIL scale, and Study of Osteoporotic Fracture (SOF) scale. Multiple regression analyses were performed to investigate whether results from gustatory function tests independently correlated with frailty.

RESULTS

Among the enrolled patients with CKD, 14 (17.9%) were found to be frail. We discovered that higher taste strip scores, or better taste function, were significantly associated with a lower frail probability (odds ratio [OR] 0.74 per score, 95% confidence interval [CI] 0.57-0.97), independent of clinical features, while better subjective taste function (OR 0.84 per score, 95% CI 0.74-0.96) and better oral cavity intactness (OR, 0.94; 95% CI, 0.9-0.98) were similarly associated with a lower frail probability among patients with CKD.

CONCLUSION

Gustatory dysfunction may be an important risk factor for frailty in patients with CKD. It is tempting to presume that interventions aiming to ameliorate such deficits may bear the potential of reducing frailty severity in this population with a high frailty burden.

Selective Peripheral Taste Dysfunction in APP/PS1 Mutant Transgenic Mice

BACKGROUND

Previous studies indicate that taste dysfunction occurs early in the development of Alzheimer's disease. It is debatable whether the deficit in taste is due primarily to peripheral sensory mechanisms or to central processing, or a combination of the two.

OBJECTIVE

The aim of our current study is to combine behavior and histological data in APP/PS1 transgenic mice to determine whether APP/PS1 transgenic mice show deficits in unconditioned taste preference and avoidance behaviors and whether taste impairments are due to defects in the peripheral taste system and/or problems with central processing of taste information.

METHODS

The APP/PS1 transgenic mutant mice were used as a model of Alzheimer's disease. We employed a brief-access gustometer test to assess immediate orosensory taste responses of APP/PS1 mice. We used immunohistochemistry to examine tongue, gustatory ganglion, and brain tissues to determine a cytological basis for behavioral deficits.

RESULTS

There is a significant, selective reduction of bitter taste sensitivity in APP/PS1 mice. These mice also have a loss of TRPM5-expressing taste receptor cells in the circumvallate papillae of the tongue. While we observed no overt loss of neuron cell bodies within the primary gustatory sensory neurons, degeneration of the neurons' peripheral axons innervating the taste bud may play a role in the observed loss of TRPM5-expressing taste receptor cells.

CONCLUSION

This data supports a potential role for peripheral taste dysfunction in AD through the selective loss of taste receptor cells. Further study is necessary to delineate the mechanisms and pathological significance of this deficit in AD.

Sensory and cognitive functions, gait ability and functionality of older adults

Objective:

to know the relationship between the sensory function, gait ability, and cognitive function with dependency in older adults.

Method:

a descriptive cross-sectional design, 146 older adults took part.

Measurements:

Snellen chart, Audiometer, Stereognosia tests, Semmes-Weinstein monofilament, basic aromas and flavors, GAITRite system, Montreal Cognitive Assessment Test, the Barthel Index, and the Lawton and Brody Index.

Results:

sensory function, cognitive function and gait explain 25% dependence on basic activities of daily life and 21% dependence on instrumental activities of daily life. The variables that influence dependence on basic activities were taste (p=.029), gait speed (p=.009), cadence (p=.002) and step length (p=.001) and, in instrumental activities, gait speed (p=.049), cadence (p=.028) and step length (p=.010).

Conclusion:

gait speed, cadence and stride length are variables that influence both dependence on basic and instrumental activities of daily life.

Acceptability of oral liquid pharmaceutical products in older adults: palatability and swallowability issues

Background

In institutional care, oral liquid pharmaceutical products are widely prescribed for older patients, especially for those with swallowing disorders. As medicines acceptability is a key factor for compliance in the older population, this study investigated the acceptability of oral liquid pharmaceutical products in this targeted population.

Methods

An observational, multicenter, prospective study was conducted in eight geriatric hospitals and eight nursing homes in France. Observers reported several behaviours/events describing the many aspects of acceptability for various pharmaceutical products’ uses in patients aged 65 and older. Acceptability scores of oral liquid pharmaceutical products were obtained using an acceptability reference framework (CAST - ClinSearch Acceptability Score Test®): a 3D-map summarizing the different users’ behaviors, with two clusters defining the positively and negatively accepted profiles materialized by the green and red zones, respectively.

Results

Among 1288 patients included in the core study and supporting the acceptability reference framework, 340 assessments were related to the administration of an oral liquid pharmaceutical product. The mean age of these patients was 87 (Range [66-104y]; SD = 6.7), 68% were women and 16% had swallowing disorders. Globally, the oral liquid pharmaceutical products were classified as “positively accepted,” the barycenter of the 340 assessments, along with the entire confidence ellipses surrounding it, were positioned on the green zone of the map. Sub-populations presenting a different acceptability profile have also been identified. For patients with swallowing disorders, the oral liquid pharmaceutical products were classified as “negatively accepted,” the barycenter of the 53 assessments along with 87% of its confidence ellipses were associated with this profile. A gender difference was observed for unflavored oral liquids. In women, they were classified “negatively accepted,” the barycenter of the 68 assessments with 75% of its confidence ellipses were located in the red zone, while they were classified “positively accepted” in men.

Conclusion

This study showed that oral liquid pharmaceutical products are a suboptimal alternative to solid oral dosage forms in patients with swallowing disorders. To ensure an optimal acceptability, prescribers should also consider the presence of a taste-masker in these oral liquids. As highlighted herein, palatability remains crucial in older populations, especially for women.