There have been many attempts at explaining age-related cognitive decline on the basis of regional brain changes, with the usual but inconsistent findings being that smaller gray matter volumes in ...certain brain regions predict worse cognitive performance in specific domains. Additionally, compromised white matter integrity, as suggested by white matter hyperintensities or decreased regional white matter fractional anisotropy, has an adverse impact on cognitive functions. The human brain is, however, a network and it may be more appropriate to relate cognitive functions to properties of the network rather than specific brain regions. We report on graph theory-based analyses of diffusion tensor imaging tract-derived connectivity in a sample of 342 healthy individuals aged 72-92 years. The cognitive domains included processing speed, memory, language, visuospatial, and executive functions. We examined the association of these cognitive assessments with both the connectivity of the whole brain network and individual cortical regions. We found that the efficiency of the whole brain network of cortical fiber connections had an influence on processing speed and visuospatial and executive functions. Correlations between connectivity of specific regions and cognitive assessments were also observed, e.g., stronger connectivity in regions such as superior frontal gyrus and posterior cingulate cortex were associated with better executive function. Similar to the relationship between regional connectivity efficiency and age, greater processing speed was significantly correlated with better connectivity of nearly all the cortical regions. For the first time, regional anatomical connectivity maps related to processing speed and visuospatial and executive functions in the elderly are identified.
In this multicenter study on subjective cognitive decline (SCD) in community-based and memory clinic settings, we assessed the (1) incidence of Alzheimer's disease (AD) and non-AD dementia and (2) ...determinants of progression to dementia.
Eleven cohorts provided 2978 participants with SCD and 1391 controls. We estimated dementia incidence and identified risk factors using Cox proportional hazards models.
In SCD, incidence of dementia was 17.7 (95% Poisson confidence interval 15.2-20.3)/1000 person-years (AD: 11.5 9.6-13.7, non-AD: 6.1 4.7-7.7), compared with 14.2 (11.3-17.6) in controls (AD: 10.1 7.7-13.0, non-AD: 4.1 2.6-6.0). The risk of dementia was strongly increased in SCD in a memory clinic setting but less so in a community-based setting. In addition, higher age (hazard ratio 1.1 95% confidence interval 1.1-1.1), lower Mini–Mental State Examination (0.7 0.66-0.8), and apolipoprotein E ε4 (1.8 1.3-2.5) increased the risk of dementia.
SCD can precede both AD and non-AD dementia. Despite their younger age, individuals with SCD in a memory clinic setting have a higher risk of dementia than those in community-based cohorts.
•A large collaborative study indicates subjective cognitive decline (SCD) is a prodrome of Alzheimer's disease and non-Alzheimer's disease dementia.•Incidence of dementia for SCD is 17.7 (95% confidence interval 15.2-20.3)/1000 person-years.•Risk factors for progression from SCD to dementia are age, lower MMSE, and APOE.•SCD in a memory clinic setting increased the risk of dementia.
To determine whether severe perivascular space (PVS) dilation is associated with longitudinal cognitive decline and incident dementia over 4 and 8 years, respectively, we analyzed data from a ...prospective cohort study.
A total of 414 community-dwelling older adults aged 72-92 years were assessed at baseline and biennially for up to 8 years, with cognitive assessments, consensus dementia diagnoses, and 3T MRI. The numbers of PVS in 2 representative slices in the basal ganglia (BG) and centrum semiovale (CSO) were counted and severe PVS pathology defined as the top quartile. The effects of severe PVS pathology in either region or both regions and those with severe BG PVS and severe CSO PVS were examined. White matter hyperintensity volume, cerebral microbleed number, and lacune number were calculated.
Participants with severe PVS pathology in both regions or in the CSO alone had greater decline in global cognition over 4 years, even after adjustment for the presence of other small vessel disease neuroimaging markers. The presence of severe PVS pathology in both regions was an independent predictor of dementia across 8 years (odds ratio 2.91, 95% confidence interval 1.43-5.95,
= 0.003). The presence of severe PVS pathology in all groups examined was associated with greater dementia risk at either year 4 or 6.
Severe PVS pathology is a marker for increased risk of cognitive decline and dementia, independent of other small vessel disease markers. The differential cognitive associations for BG and CSO PVS may represent differences in their underlying pathology.
The relationship of dietary patterns to cognitive health in older adults has attracted much research attention. However, results from existing studies are inconclusive.
The aim of this study was to ...investigate the association between dietary patterns and overall cognitive performance and cognitive change over time.
This analysis was conducted as part of the longitudinal Sydney Memory and Ageing study with 6 years’ follow-up. Mediterranean diet and Dietary Approaches to Stop Hypertension diet scores were generated based on dietary intake for each individual, assessed by the Dietary Questionnaire for Epidemiological Studies Version 2.
This longitudinal study comprised 1037 community dwelling nondemented participants aged 70 to 90 years at baseline (September 2005 to December 2007), recruited from Sydney, Australia.
Neuropsychological tests assessed global cognition and 6 cognitive domains on 4 occasions, at baseline and 2, 4, and 6 years later.
Linear mixed-model analyses were conducted to examine the relationship between dietary scores, food components, and overall cognitive function and cognitive change over 6 years.
No associations of Mediterranean or Dietary Approaches to Stop Hypertension dietary scores with overall cognition and cognitive decline over 6 years were found. Higher intake of legumes and nuts was related to better overall performance in global cognition (β = .091; 95% CI: 0.035-0.146; P = .001) and to multiple cognitive domains and to less decline in global cognition (β = −.016; 95% CI: −0.032 to −0.001; P = .032).
Study findings suggest that greater consumption of legumes and nuts may be important to slow cognitive decline with age.
Both cognitive ability and cognitive decline have been shown to predict mortality in older people. As dementia, a major form of cognitive decline, has an established association with shorter ...survival, it is unclear the extent to which cognitive ability and cognitive decline predict mortality in the absence of dementia.
To determine whether cognitive ability and decline in cognitive ability predict mortality in older individuals without dementia.
The Sydney Memory and Ageing Study is an observational population-based cohort study. Participants completed detailed neuropsychological assessments and medical examinations to assess for risk factors such as depression, obesity, hypertension, diabetes, hypercholesterolaemia, smoking and physical activity. Participants were regularly assessed at 2-year intervals over 8 years.
A community sample in Sydney, Australia.
One thousand and thirty-seven elderly people without dementia.
Overall, 236 (22.8%) participants died within 8 years. Both cognitive ability at baseline and decline in cognitive ability over 2 years predicted mortality. Decline in cognitive ability, but not baseline cognitive ability, was a significant predictor of mortality when depression and other medical risk factors were controlled for. These relationships also held when excluding incident cases of dementia.
The findings indicate that decline in cognition is a robust predictor of mortality in older people without dementia at a population level. This relationship is not accounted for by co-morbid depression or other established biomedical risk factors.
Word-finding difficulty is typically an early and frustrating symptom of primary progressive aphasia (PPA), prompting investigations of lexical retrieval treatment in PPA. This study aimed to ...investigate immediate treatment gains following two versus four weeks of treatment, item generalisation, and maintenance of gains with ongoing treatment in a single case series of eight individuals with heterogeneous PPA presentations (three non-fluent/agrammatic, two logopenic, two semantic, and one mixed PPA). Three individuals made initial gains in picture naming and maintained them over 6 months or more with ongoing treatment. By contrast, three individuals made marginal initial gains but were unable to continue treatment, and two individuals did not make the typically-reported initial gains with two or four weeks of treatment. There was little evidence of generalisation to untreated items. Our results add to the evidence that daily home practice of Repetition and Reading in the Presence of a Picture over extended periods can increase and maintain retrieval of personally-relevant words in picture naming for some individuals with semantic or nonfluent/agrammatic variant PPA. Further research is needed into the factors associated with long-term treatment adherence and gains, and the factors associated with nonadherence to treatment.
The Telephone Interview for Cognitive Status-modified (TICS-M) is a well-established and widely used screening instrument for dementia and assessment of global cognitive function in older people. ...This study aimed to evaluate the psychometric properties of the TICS-M and to enhance the accuracy of the instrument using Rasch methodology. Partial Credit Rasch model was applied to the TICS-M scores. The sample selected for Rasch analysis consisted of 432 participants aged 70-90 years (M = 78.85, SD = 4.73) including 195 males (237 females), and 132 (30.56%) of whom were diagnosed with dementia after the baseline assessment. Initial analysis indicated good reliability of the TICS-M assessment scores, but there were three misfitting items and local dependency issues. Combining locally dependent and misfitting items into super-items achieved the best Rasch model fit for the TICS-M. This modification improved reliability of the assessment scores and resulted in no misfitting items, no local dependency, strict unidimensionality, and invariance across individual factors such as participants age, sex, diagnosis, and in-person neuropsychological assessment scores. Satisfying Rasch model expectations allowed for creation of a transformation table to convert raw TICS-M scores into interval-level data, which improves precision of the instrument. In summary, the TICS-M assessment scores demonstrated excellent reliability as reflected by Person Separation Index (PSI = 0.86) and met expectations of the unidimensional Rasch model after minor adjustments. The ordinal-to-interval transformation table can be used to increase accuracy of the TICS-M without altering its current format. These findings contribute to more accurate assessments of cognitive decline in older people and screening for conditions such as dementia.
Public Significance Statement
Rasch analysis is an advanced statistical method that is increasingly becoming a gold standard for examining and improving accuracy of clinical outcome measures. This study applied Rasch analysis to investigate measurement characteristics of the Telephone Interview for Cognitive Status-modified and performed important modifications to enhance its accuracy for capturing global cognition among older adults with and without dementia.
There is widespread consumer concern that statin use may be associated with impaired memory and cognitive decline.
This study sought to examine the association between statin use and changes in ...memory and global cognition in the elderly population over 6 years and brain volumes over 2 years. Interactions between statin use and known dementia risk factors were examined.
Prospective observational study of community-dwelling elderly Australians age 70 to 90 years (the MAS Sydney Memory and Ageing Study, n = 1,037). Outcome measures were memory and global cognition (by neuropsychological testing every 2 years) and total brain, hippocampal and parahippocampal volumes (by magnetic resonance) in a subgroup (n = 526). Analyses applied linear mixed modeling, including the covariates of age, sex, education, body mass index, heart disease, diabetes, hypertension, stroke, smoking, and apolipoprotein Eε4 carriage. Interactions were sought between statin use and dementia risk factors.
Over 6 years there was no difference in the rate of decline in memory or global cognition between statin users and never users. Statin initiation during the observation period was associated with blunting the rate of memory decline. Exploratory analyses found statin use was associated with attenuated decline in specific memory test performance in participants with heart disease and apolipoprotein Eε4 carriage. There was no difference in brain volume changes between statin users and never users.
In community-dwelling elderly Australians, statin therapy was not associated with any greater decline in memory or cognition over 6 years. These data are reassuring for consumers concerned about statin use and risk of memory decline.
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Changes in criteria and differences in populations studied and methodology have produced a wide range of prevalence estimates for mild cognitive impairment (MCI).
Uniform criteria were applied to ...harmonized data from 11 studies from USA, Europe, Asia and Australia, and MCI prevalence estimates determined using three separate definitions of cognitive impairment.
The published range of MCI prevalence estimates was 5.0%-36.7%. This was reduced with all cognitive impairment definitions: performance in the bottom 6.681% (3.2%-10.8%); Clinical Dementia Rating of 0.5 (1.8%-14.9%); Mini-Mental State Examination score of 24-27 (2.1%-20.7%). Prevalences using the first definition were 5.9% overall, and increased with age (P < .001) but were unaffected by sex or the main races/ethnicities investigated (Whites and Chinese). Not completing high school increased the likelihood of MCI (P ≤ .01).
Applying uniform criteria to harmonized data greatly reduced the variation in MCI prevalence internationally.
OBJECTIVES
Telephone‐based cognitive screens, such as the Telephone Interview for Cognitive Status (TICS), can potentially reduce the barriers and costs of assessing older adults. However, validation ...of clinically relevant psychometric properties is lacking in a large and comprehensively assessed sample of older adults. Furthermore, published normative data may lack sensitivity as they have not used regression‐based demographic corrections or accounted for cases with subsequent dementia. We address these gaps using the modified TICS (TICS‐M; a modified, 13‐item, 39‐point version) and provide an online norms calculator for clinicians and researchers.
DESIGN
Prospective longitudinal study.
SETTING
Sydney, Australia.
PARTICIPANTS
A total of 617 community‐living older adults, aged from 71 to 91 years.
MEASUREMENTS
The measures used included the TICS‐M, the Mini‐Mental State Examination (MMSE), Addenbrooke's Cognitive Examination‐Revised (ACE‐R), and a comprehensive neuropsychological test battery. Descriptive statistics, correlations, area under the curve, and regression analyses were used to determine the validity and normative properties of the TICS‐M.
RESULTS
TICS‐M total scores (mean = 24.20; SD = 3.76) correlated well with the MMSE (0.70) and ACE‐R (0.80) and moderately with neuropsychological tests tested noncontemporaneously. A cutoff score of 21 or lower reliably distinguished between those with and without incident dementia after 1 year (sensitivity = 77%; specificity = 88%) but was less reliable at distinguishing mild cognitive impairment from normal cognition. TICS‐M scores decreased with age and increased with higher education levels. The robust normative sample, which excluded incident dementia cases, scored higher on the TICS‐M and with less variability than the whole sample. An online calculator is provided to compute regression‐based norms and reliable change statistics.
CONCLUSIONS
In a large sample of community‐dwelling older adults, the TICS‐M performed well in terms of construct validity against typical screening tools and neuropsychological measures and diagnostic validity for incident dementia. The comprehensive, regression‐based, and robust normative data provided will help improve the sensitivity, accessibility, and cost‐effectiveness of cognitive testing with older adults. J Am Geriatr Soc 67:2108–2115, 2019
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