The relationship between olfaction and cognitive function in the elderly

Uchida, Sae; Shimada, Chiho; Sakuma, Naoko; Kagitani, Fusako; Kan, Akiko; Awata, Shuichi

doi:10.1186/s12576-020-00777-8

Cited by 10 publications

(17 citation statements)

References 35 publications

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“…The TMT is not only sensitive to changes in cognitive function due to brain injury ( Reitan, 1958 ); it may also detect those that occur due to aging and education ( Hashimoto et al, 2006 ; Specka et al, 2021 ). The TMT is widely used in the evaluation of cognitive function in older adults, including evaluation indicators in intervention studies ( Jacobs et al, 2020 ; Suzuki et al, 2020 ), driving performance in older adults ( Vaucher et al, 2014 ), and studies examining the relationship between physiological indicators and attention function ( Uchida et al, 2020 ). Both TMT scores are sensitive to progressive cognitive decline associated with dementia ( Greenlief et al, 1985 ).…”

Section: Introductionmentioning

confidence: 99%

Normative Data of the Trail Making Test Among Urban Community-Dwelling Older Adults in Japan

Suzuki

Sakuma

Kobayashi

et al. 2022

Front. Aging Neurosci.

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IntroductionPopulation aging is likely to increase the number of people with dementia living in urban areas. The Trail Making Test (TMT) is widely used as a cognitive task to measure attention and executive function among older adults. Normative data from a sample of community-dwelling older adults are required to evaluate the executive function of this population. The purpose of this study was to examine the Trail Making Test completion rate and completion time among urban community-dwelling older adults in Japan.MethodsA survey was conducted at a local venue or during a home visit (n = 1,966). Cognitive tests were conducted as a part of the survey, and TMT Parts A (TMT-A) and B (TMT-B) were completed after the completion of the Japanese version of the Mini-Mental State Examination (MMSE-J). Testers recorded TMT completion status, completion time, and the number of errors observed.ResultsIn the TMT-A, 1,913 (99.5%) participants understood the instructions, and 1,904 (99.1%) participants completed the task within the time limit of 240 s. In the TMT-B, 1,839 (95.9%) participants understood the instructions, and 1,584 (82.6%) participants completed the task within the time limit of 300 s. The completion rate of TMT-B was 90.2 and 41.8% for participants with an MMSE-J score of >23 points and ≦23 points, respectively. Results of multiple regression analyses showed that age, education, and the MMSE-J score were associated with completion time in both TMTs.ConclusionIn both TMTs, completion time was associated with age, education, and general cognitive function. However, not all participants completed the TMT-B, and the completion rate was relatively low among participants with low MMSE-J scores. These findings may help interpret future TMT assessments.

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Section: Introductionmentioning

confidence: 99%

Normative Data of the Trail Making Test Among Urban Community-Dwelling Older Adults in Japan

Suzuki

Sakuma

Kobayashi

et al. 2022

Front. Aging Neurosci.

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“…Previous research has also suggested that cholinergic neurons in the basal forebrain may explain the relationship between olfaction and attentional ability. 17 A line of research has suggested that the impairment of the cholinergic basal forebrain is related to both olfactory dysfunction and cognitive impairment, especially attention and memory. 49 Use of anticholinergic medication has been associated with greater brain atrophy and cognitive decline among cognitively normal older adults.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies examining neuropsychological function in older adults are mostly cross-sectional and have reported that olfactory function, specifically odor identification, is associated with global cognitive function, verbal memory, attention, executive function, fluency, psychomotor speed, and manual dexterity. 2,[17][18][19][20][21][22][23] Data on the relation between olfaction and longitudinal changes in domain-specific neuropsychological function are limited, especially in domains involving a motor component, such as psychomotor speed and manual dexterity. 24,25 To address prior limitations, in this study we examined associations of olfactory function with longitudinal changes in brain volumes and neuropsychological function over time in a sample of well-characterized community-dwelling adults from the Baltimore Longitudinal Study of Aging (BLSA).…”

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confidence: 99%

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confidence: 99%

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Associations of Olfaction With Longitudinal Trajectories of Brain Volumes and Neuropsychological Function in Older Adults

Tian

Triolo

et al. 2023

Neurology

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Background and objectives:Olfactory function declines with aging and olfactory deficits are one of the earliest features of neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. Previous studies have shown that olfaction is associated with brain volumes and cognitive function, but data are exclusively cross-sectional. We aimed to examine longitudinal associations of olfaction with changes in brain volumes and neuropsychological function.Methods:In the Baltimore Longitudinal Study of Aging, we chose the first assessment of olfaction to examine the associations with retrospective and prospective changes in neuropsychological performance and brain volumes in participants aged 50 or older using linear mixed-effects models, adjusted for demographic variables and cardiovascular disease. Olfaction was measured as odor identification scores via the 16-item Sniffin’ sticks.Results:We analyzed data from 567 (58% women, 42% men, 27% Black, 66% White, 7% Others) participants who had data on odor identification scores and brain volumetric MRI (n=420 with retrospective repeats over a mean of 3.7 years, n=280 with prospective repeats over a mean of 1.2 years). We also analyzed data from 754 participants (56% women, 44% men, 29% Black, 65% White, 6% Others) with neuropsychological assessments (n=630 with retrospective repeats over a mean of 6.6 years, n=280 with prospective repeats over a mean of 1.5 years). After adjustment, higher odor identification scores were associated with prior and subsequent slower brain atrophy in entorhinal cortex (β±SE=0.0093±0.0031,p=0.0028 and β±SE=0.0176±0.0073,p=0.0169,respectively), hippocampus (β±SE=0.0070±0.0030,p=0.0192 and β±SE=0.0173±0.0066,p=0.0089,respectively), and additional frontal and temporal areas (all p<0.05). Higher odor identification scores were also associated with prior slower decline in memory, attention, processing speed, and manual dexterity, and subsequent slower decline in attention (all p<0.05). Some associations were attenuated after exclusion of data points at and after symptom onset of cognitive impairment or dementia.Discussion:In older adults, olfaction is related to brain atrophy of specific brain regions and neuropsychological changes in specific domains over time. The observed associations are driven, in part, by those who developed cognitive impairment or dementia. Future longitudinal studies with longer follow-ups are needed to understand whether olfactory decline precedes cognitive decline and whether it is mediated through regionally-specific brain atrophy.

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“…Also, the condition was found to be minimized in the presence of cholinesterase inhibitors. 15 People who showed olfactory loss were found to have a higher chance of the modification of disease state to show dementia symptoms. The olfactory impairment occurring in the early stages can hence be linked to the involvement of the cerebral cortex and, therefore, is applicable as a biomarker for assessment of patients with PD on the risk of the developing cognitive deficits and conditions like dementia.…”

Section: Methodsmentioning

confidence: 99%

The Role of Olfactory System in the Etiogenesis of Parkinson’s Diseases: An Overview

Avanipully

Thekkekkara

Sahyadri

et al. 2022

Journal of Pharmacology and Pharmacotherapeutics

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Parkinson’s disease (PD) mainly affects the dopaminergic neuronal networks of the substantia nigra, which leads to both motor and nonmotor symptoms of the disease. Based on the reports from the previous studies, 95% of the cases are presented along with olfactory dysfunction. The relevant publications from 2002 to 2021 were searched and shortlisted using PubMed and Google Scholar. In this review, we have discussed the correlation between olfactory dysfunction and PD. Olfactory damage presents earlier than the motor symptoms. Because there are no current methodologies for the early detection of PD, olfactory dysfunction can be used as a potential marker for the early detection of PD and hence paving the way for better therapeutic approaches.

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The relationship between olfaction and cognitive function in the elderly

Cited by 10 publications

References 35 publications

Normative Data of the Trail Making Test Among Urban Community-Dwelling Older Adults in Japan

Normative Data of the Trail Making Test Among Urban Community-Dwelling Older Adults in Japan

Associations of Olfaction With Longitudinal Trajectories of Brain Volumes and Neuropsychological Function in Older Adults

The Role of Olfactory System in the Etiogenesis of Parkinson’s Diseases: An Overview

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