Optimizing mild cognitive impairment for discriminating dementia risk in the general older population

The links among age, sex, and glutathione: A cross-sectional magnetic resonance spectroscopy study

Glutathione (GSH) is a brain marker for oxidative stress and has previously been associated with cerebral amyloid deposition and memory decline. However, to date, no study has examined the links among GSH, sex, age, amyloid, and Apolipoprotein E (APOE) genotype in a large non-clinical cohort of older adults. We performed APOE genotyping, magnetic resonance spectroscopy (MRS) as well as simultaneous positron emission tomography with the radiotracer Flutemetamol (Amyloid-PET), in a group of older adults. The final analysis set comprised 140 healthy older adults (mean age: 64.7 years) and 49 participants with mild cognitive impairment (mean age: 71.4 years). We recorded metabolites in the posterior cingulate cortex (PCC) by a GSH-edited MEGAPRESS sequence. Structural equation modeling revealed that higher GSH levels were associated with female sex, but neither APOE- epsilon 4 carrier status nor age showed significant associations with GSH. Conversely, older age and the presence of an APOE4 allele, but not sex, are linked to higher global amyloid load. Our results suggest that the PCC shows sex-specific GSH alterations in older adults.

Gait speed, handgrip strength, and cognitive impairment among older women - A multistate analysis

BACKGROUND

Cognitive impairment imposes substantial psychological, emotional, and economic burdens on affected individuals, families and society. A better understanding of potentially modifiable risk factors that may be used in the prevention of cognitive impairment is therefore a high priority in aging research.

METHODS

This study included 9268 community-dwelling women aged 65 years or older from the Study of Osteoporotic Fractures launched between 1986 and 1988 in the US. Participants were followed for 20 years. Modified Mini-Mental State Examination (m-MMSE) was administered up to 6 times. Six updated measurements of gait speed and handgrip strength at the same visit time when m-MMSE was administered were used. The m-MMSE score was used to define cognitive impairment states (normal, mild, and severe impairment). A multi-state model (MSM) was used to estimate the transitions between different states of cognitive function.

RESULTS

Faster gait speed (one unit increase of meter/s) was associated with lower risk of transition from cognitively normal status to mild cognitive impairment (HR = 0.50, 95 % CI: 0.37-0.67), and from mild impairment to severe impairment (HR = 0.52, 95 % CI: 0.37-0.72). Higher gait speed was associated with increased risk of cognitive transition from severe impairment to mild impairment (HR = 2.56 95 % CI: 0.97-6.77), although the result did not reach statistical significance. Similarly, we observed greater handgrip strength (per kg increase) was associated with lower risk of transition of cognitive status from normal to mild impairment (HR = 0.96 95 % CI: 0.95-0.97), and from mild to severe impairment (HR = 0.98, 95 % CI: 0.96-0.99). Greater handgrip strength was associated with increased risk of cognitive transition from severe to mild cognitive impairment (HR = 1.05, 95 % CI: 1.01-1.09). In addition, we also observed that both faster gait speed and greater handgrip strength were associated with lower risk of transitions from normal or mild cognitive impairment status to death.

CONCLUSION

Our results confirmed that screening for slow gait speed or weak handgrip strength may be useful for identifying older adults at risk for cognitive decline when they are still cognitively normal or only mildly impaired. Exercise programs to improve gait speed and muscle strength may delay or prevent transitions into cognitive impairment in older adults.

Evaluation of mild cognitive impairment genetic susceptibility risks in a Chinese population

BACKGROUND

Mild cognitive impairment (MCI) is a kind of non-functional cognitive decline between normal aging and dementia. With the increase of individual age, the quality of cognitive function has become a more and more important topic. The study of gene loci in patients with MCI is essential for the prevention of dementia. In this study, we evaluate the gene polymorphism in Chinese Han patients with MCI by propensity score matching (PSM) and comparing them to healthy control (HC) subjects.

METHODS

Four hundred seventeen patients with mild cognitive impairment and 508 healthy people were included. The two groups were matched by applying one-to-one PSM, and the matching tolerance was set to 0.002. The matching covariates included gender,age,occupation,marital status,living mode. Then, a case-control associated analysis was conducted to analyze the genotype and allele frequencies of single nucleotide polymorphisms (SNPs) in the MCI group and the control group.

RESULTS

Three hundred eleven cases were successfully matched in each group, and there was no statistical difference on all the matching variables, gender, age, occupation, marital status, living mode between two groups after the match (P > 0.05). The allele frequency of bridging integrator 1(BIN1) rs7561528 showed minimal association with MCI in the Han Chinese population (P = 0.01). Compared with the healthy control (HC) group, A allele frequency of MCI group patients was significantly decreased. The genotype frequency of BIN1 rs6733839 showed minimal association with MCI in the recessive model (P = 0.03). The genotype frequency of rs7561528 showed minimal association with MCI in the codominant, dominant, overdominant, and log-additive model (P < 0.05). The genotype frequencies of StAR-related lipid transfer domain 6 (STARD6) rs10164112 showed nominal association with MCI in the codominant, dominant, and log-additive model (P < 0.05). Unfortunately, the significant differences did not survive Benjamini-Hochberg false discovery rate correction (adjusted P > 0.05). The patients with SPI1 rs1057233 may be the protective factor of MCI (OR = 0.733, 95%CI 0.625-0.859, P < 0.001), and patients with APOE rs10164112 may be a risk factor for MCI (OR = 1.323, 95%CI 1.023-1.711, P = 0.033).

CONCLUSIONS

The polymorphisms of rs7561528, rs6733839 loci in the BIN1 gene, and rs1057233 loci in the SPI1 gene may be associated with the MCI in Chinese Han population. APOE gene was the risk factor of MCI, but further verification in a large sample population is still needed.

Effect of long-term lifestyle intervention on mild cognitive impairment in hypertensive occupational population in China

BACKGROUND

The incidence of hypertension in China is high, which seriously affects people's health, including occupational population in mining areas. Cognitive dysfunction has a serious impact on the work and life of patients. Lifestyle intervention can improve diabetes and cardiovascular diseases. However, there are few studies on the effects of lifestyle interventions on cognitive function in hypertensive patients. So the aim of this study was to analyze the effect of long-term lifestyle intervention on mild cognitive impairment in hypertensive occupational population in China.

METHODS

In September 2013, a cluster sampling was conducted for the workers in the Shaanxi Jinduicheng (intervention group) and Hancheng (control group) mining areas. In both groups, according to the blood pressure (BP) level, they were divided into hypertension stage 1 to 3 subgroups; according to their age, they were divided into between 45 and 59 and under 45 years subgroups; and according to whether or not taking medicine, they were divided into Lifestyle intervention, Lifestyle intervention plus medication, Medication, and No lifestyle intervention nor medication subgroups. The intervention group received regular lifestyle intervention for 2 years, which included diet, smoke, drink, and exercise intervention. Mild cognitive impairment was measured by the Montreal Cognitive Assessment (MoCA). The arterial stiffness was measured by Omron Automatic Atherosclerosis Tester. We conducted BP measurement and MoCA questionnaire at baseline, 6, 12, and 24 months.

RESULTS

We analyzed a total of 510 mine workers, whose average age was 45.6 ± 13.4 years old. With the increase of BP level, the MoCA scores decreased significantly both in control and lifestyle intervention groups (P < .05). There was no obvious difference between the hypertensive patients whose age was between 45 and 59 to those under 45 in MoCA scores (P > .05). After 2 years, the BP, total cholesterol, glucose, and brachial-ankle pulse wave velocity of the Lifestyle intervention subgroup and Lifestyle intervention plus medication subgroup decreased (P < .05), and the MoCA scores and ankle-brachial index increased (P < .05), and the latter improved more significantly. Compared with the No lifestyle intervention nor medication subgroup, the BP and MoCA scores had no obvious changes at 6 months (P > .05), but the BP decreased and the MoCA scores increased significantly in the Lifestyle intervention and Lifestyle intervention plus medication subgroups after 1 and 2 years of lifestyle intervention (P < .05).

CONCLUSION

Long-term lifestyle intervention can be used as adjunctive therapy to improve the BP and cognitive function of hypertensive occupational population in China.

Neuropsychiatric symptoms as risk factors of dementia in a Mexican population: A 10/66 Dementia Research Group study

Introduction

Cognitive and/or memory impairment are the main clinical markers currently used to identify subjects at risk of developing dementia. This study aimed to explore the relationship between the presence of neuropsychiatric symptoms and dementia incidence.

Methods

We analyzed the association between neuropsychiatric symptoms and incident dementia in a cohort of 1355 Mexican older adults from the general population over 3 years of follow-up, modeling cumulative incidence ratios using Poisson models.

Results

Five neuropsychiatric symptoms were associated with incident dementia: delusions, hallucinations, anxiety, aberrant motor behavior, and depression. The simultaneous presence of two symptoms had a relative risk, adjusted for mild cognitive impairment, diabetes, indicators of cognitive function, and sociodemographic factors, of 1.9 (95% confidence interval, 1.2–2.9), whereas the presence of three to five, similarly adjusted, had a relative risk of 3.0 (95% confidence interval, 1.9–4.8).

Discussion

Neuropsychiatric symptoms are common in predementia states and may independently contribute as risk factors for developing dementia.

•

Not only cognitive impairment and cognitive features are useful in identifying older adults at risk for developing dementia.

•

Of the 12 neuropsychiatric symptoms evaluated, 5 were associated with incident dementia (delusions, hallucinations, depression, anxiety, and aberrant motor behavior) in a 3-year follow-up.

•

The evaluation of neuropsychiatric symptoms, along with other simple, practical, and inexpensive features, may be useful in identifying subjects at risk of dementia in community health settings and by general practitioners.

Neuropsychological profiles of vascular disease and risk of dementia: implications for defining vascular cognitive impairment no dementia (VCI-ND)

Background

vascular cognitive impairment no dementia (VCI-ND) defines a preclinical phase of cognitive decline associated with vascular disorders. The neuropsychological profile of VCI-ND may vary according to different vascular conditions.

Objective

to determine the neuropsychological profile of individuals with no dementia and vascular disorders, including hypertension, peripheral vascular disease (PVD), coronary heart disease (CHD), diabetes and stroke. Risk of 2-year incident dementia in individuals with disease and cognitive impairment was also tested.

Methods

participants were from the Cognitive Function and Ageing Study. At baseline, 13,004 individuals aged ≥65 years were enrolled into the study. Individuals were grouped by baseline disorder status (present, absent) for each condition. Cognitive performance was assessed using the Mini Mental State Examination (MMSE) and the Cambridge Cognitive Examination (CAMCOG). Dementia was assessed at 2 years.

Results

in the cross-sectional analysis, hypertension, PVD and CHD were not associated with cognitive impairment. Stroke was associated with impaired global (MMSE) and CAMCOG sub-scale (including memory and non-memory) scores. Diabetes was associated with impairments in global cognitive function (MMSE) and abstract thinking. In the longitudinal analysis, cognitive impairments were associated with incident dementia in all groups.

Conclusion

the neuropsychological profile in individuals with vascular disorders depends on the specific condition investigated. In all conditions cognitive impairment is a risk factor for dementia. A better understanding of which cognitive domains are affected in different disease groups could help improve operationalisation of the neuropsychological criteria for VCI-ND and could also aid with the development of dementia risk prediction models in persons with vascular disease.

Potential Value of Impaired Cognition in Stroke Prediction: A U.K. Population-Based Study

Objectives

To determine whether the association between impaired cognition and greater risk of incident stroke is also observed when cognitive impairment is defined using different criteria for mild cognitive impairment (MCI).

Design

Prospective cohort study with 10 years of follow‐up.

Setting

Large multicentre study in the United Kingdom.

Participants

Individuals (aged 64–105) from the Medical Research Council Cognitive Function and Ageing Study (N = 13,004). From this, a subsample of 2,640 individuals was selected based on age, center, and cognitive ability to undergo a detailed cognitive assessment.

Measurements

Information on sociodemographic characteristics, health, cognition, and functional ability was collected in an interview. The Geriatric Mental State Automated Geriatric Examination for Computer Assisted Taxonomy and the Cambridge Cognitive Examination were used to determine cognitive status. Stroke incidence was derived from self‐report, informant report, and death certificates. Participants were divided into no, mild, moderate, and severe cognitive impairment according to their baseline Mini‐Mental State Examination (MMSE) score. MCI criteria were used to classify persons into four groups: no cognitive impairment, MCI, severe impairment (i.e. other cognitive impairment no dementia: OCIND) and dementia.

Results

Over 10 years, 703 incident strokes occurred. Lower MMSE score at baseline was associated with greater risk of incident stroke. When cognitive status was determined according to MCI criteria, those with severe impairment (odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.0–2.2) and dementia (OR = 2.6, 95% CI = 1.6–3.4) had a significantly greater risk of stroke than those with no cognitive impairment.

Conclusion

Criteria for MCI, defined using MMSE scores or clinical criteria, can capture individuals at greater stroke risk. The results highlight the need to focus on stroke risk in individuals even with MCI.

Patterns and persistence of behavioural and psychological symptoms in those with cognitive impairment: the importance of apathy

OBJECTIVE

To study the stability and emergence of a range of behavioural and psychological symptoms (BPS), their association with mortality and the effect of covariates on these transitions in a population-based study of cognitively impaired older people with a long follow-up period and large sample size, with a particular focus on apathy.

METHODS

Data were from a population-based, longitudinal cohort study of ageing. Interviews were conducted at 0, 2, 6, 8 and 10 years with 3626 participants aged 65+. The persistence of 11 BPS and their association with mortality in those with cognitive impairment (MMSE 25 or below) was investigated using multi-state models, allowing us to take into account estimations of the probability of transitions that occurred in the time between interviews.

RESULTS

Most BPS were persistent. Apathy was one of the most stable symptoms; in those with apathy, the probability of still having apathy after 1 year is 62%. Apathy, sleep problems, depression, irritability and wandering were most likely to develop. BPS are associated with mortality; in those with apathy, mortality is 3.1 times more likely than in those without apathy. Low cognitive function and dementia were associated with emergence of new symptoms.

CONCLUSIONS

This population-based, multi-centre study with a follow-up period of 10 years showed that BPS are associated with mortality and most symptoms are persistent. Apathy was characterised by a high prevalence, a high persistence and a strong association with mortality, and has a negative impact on disability, management of other disease and caregiver burden.

Dementia prediction for people with stroke in populations: is mild cognitive impairment a useful concept?

BACKGROUND

criteria for mild cognitive impairment (MCI) capture an intermediate cognitive state between normal ageing and dementia, associated with increased dementia risk. Whether criteria for MCI are applicable in the context of stroke and can be used to predict dementia in stroke cases is not known.

OBJECTIVES

to determine the prevalence of MCI in individuals with stroke and identify predictors of 2-year incident dementia in stroke cases.

METHODS

individuals were from the Medical Research Council Cognitive Function and Ageing Study. MCI prevalence in individuals with stroke was determined. Logistic regression, with receiver operating characteristic curve analysis, was used to identify variables associated with risk of dementia in stroke cases including MCI criteria, demographic, health and lifestyle variables.

FINDINGS

of 2,640 individuals seen at the first assessment, 199 reported stroke with no dementia. In individuals with stroke, criteria for MCI are not appropriate, with less than 1% of stroke cases being classified as having MCI. However, in individuals with stroke two components of the MCI definition, subjective memory complaint and cognitive function (memory and praxis scores) predicted 2-year incident dementia (area under the curve = 0.85, 95% CI: 0.77-0.94, n = 113).

CONCLUSION

criteria for MCI do not appear to capture risk of dementia in the context of stroke in the population. In stroke cases, subjective and objective cognitive performance predicts dementia and these variables could possibly be incorporated into dementia risk models for stroke cases. Identifying individuals with stroke at greatest risk of dementia has important implications for treatment and intervention.

Modulation of effective connectivity in the default mode network at rest and during a memory task

It is known that the default mode network (DMN) may be modulated by a cognitive task and by performance level. Changes in the DMN have been examined by investigating resting-state activation levels, but there have been very few studies examining the modulation of effective connectivity of the DMN during a task in healthy older subjects. In this study, the authors examined how effective connectivity changed in the DMN between rest and during a memory task. The authors also investigated whether there was any relationship between effective connectivity modulation in the DMN and memory performance, to establish whether variations in cognitive performance are related to neural network effective connectivity, either at rest or during task performance. Twenty-eight healthy older participants underwent a resting-state functional magnetic resonance imaging scan and an emotional face-name encoding task. Effective connectivity analyses were performed on the DMN to examine the effective connectivity modulation in these two different conditions. During the resting state, there was strong self-influence in the regions of the DMN, while the main regions with statistically significant cross-regional effective connectivity were the posterior cingulate cortex (PCC) and the hippocampus (HP). During the memory task, the self-influence effective connectivities remained statistically significant across the DMN, and there were statistically significant effective connectivities from the PCC, HP, amygdala (AM), and parahippocampal region to other DMN regions. The authors found that effective connectivities from PCC, HP, and AM (in both resting state and during task) were linearly correlated to memory performance. The results suggest that superior memory ability in this older cohort was associated with effective connectivity both at rest and during the memory task of three DMN regions, which are also known to be important for memory function.

In vivo and in vitro effects of fructose on rat brain acetylcholinesterase activity: an ontogenetic study

Increased fructose concentrations are the biochemical hallmark of fructosemia, a group of inherited disorders on the metabolic pathway of this sugar. The main clinical findings observed in patients affected by fructosemia include neurological abnormalities with developmental delay, whose pathophysiology is still undefined. In the present work we investigated the in vitro and in vivo effects of fructose on acetylcholinesterase (AchE) activity in brain structures of developing rats. For the in vitro experiments, fructose was added at increasing concentrations to the incubation medium. It was observed that fructose provoked an inhibition of acetylcholinesterase activity in cerebral cortex of 30-day-old-rats, even at low concentrations (0.1 mM). For the in vivo experiments, rats were killed 1 h after a single fructose administration (5 µmol/g). Control group received the same volume of saline solution. We found that AchE activity was increased in cerebral cortex of 30- and 60-day-old rats receiving fructose administration. Finally, we observed that AchE activity was unaffected by acute fructose administration in cerebral cortex, striatum or hippocampus of 15- and 90-day-old rats. The present data suggest that a disruption in cholinergic homeostasis may be involved in the pathophysiology of brain damage observed in young patients affected by fructosemia.

The spectrum of cognitive impairment in Lewy body diseases

Cognitive impairment represents an important and often defining component of the clinical syndromes of Lewy body disorders: Parkinson's disease and dementia with Lewy bodies. The spectrum of cognitive deficits in these Lewy body diseases encompasses a broad range of clinical features, severity of impairment, and timing of presentation. It is now recognized that cognitive dysfunction occurs not only in more advanced Parkinson's disease but also in early, untreated patients and even in those patients with pre-motor syndromes, such as rapid eye movement behavior disorder and hyposmia. In recent years, the concept of mild cognitive impairment as a transitional or pre-dementia state in Parkinson's disease has emerged. This has led to much research regarding the diagnosis, prognosis, and underlying neurobiology of mild cognitive impairment in Parkinson's disease, but has also raised questions regarding the usefulness of this concept and its application in clinical and research settings. In addition, the conundrum of whether Parkinson's disease dementia and dementia with Lewy bodies represent the same or different entities remains unresolved. Although these disorders overlap in many aspects of their presentations and pathophysiology, they differ in other elements, such as timing of cognitive, behavioral, and motor symptoms; medication responses; and neuropathological contributions. This article examines the spectrum and evolution of cognitive impairment in Lewy body disorders and debates these controversial issues in the field using point-counterpoint approaches.

Single-domain amnestic mild cognitive impairment identified by cluster analysis predicts Alzheimer's disease in the european prospective DESCRIPA study

BACKGROUND/AIMS

To identify prodromal Alzheimer's disease (AD) subjects using a data-driven approach to determine cognitive profiles in mild cognitive impairment (MCI).

METHODS

A total of 881 MCI subjects were recruited from 20 memory clinics and followed for up to 5 years. Outcome measures included cognitive variables, conversion to AD, and biomarkers (e.g. CSF, and MRI markers). Two hierarchical cluster analyses (HCA) were performed to identify clusters of subjects with distinct cognitive profiles. The first HCA included all subjects with complete cognitive data, whereas the second one selected subjects with very mild MCI (MMSE ≥28). ANOVAs and ANCOVAs were computed to examine whether the clusters differed with regard to conversion to AD, and to AD-specific biomarkers.

RESULTS

The HCAs identified 4-cluster solutions that best reflected the sample structure. One cluster (aMCIsingle) had a significantly higher conversion rate (19%), compared to subjective cognitive impairment (SCI, p < 0.0001), and non-amnestic MCI (naMCI, p = 0.012). This cluster was the only one showing a significantly different biomarker profile (Aβ42, t-tau, APOE ε4, and medial temporal atrophy), compared to SCI or naMCI.

CONCLUSION

In subjects with mild MCI, the single-domain amnestic MCI profile was associated with the highest risk of conversion, even if memory impairment did not necessarily cross specific cut-off points. A cognitive profile characterized by isolated memory deficits may be sufficient to warrant applying prevention strategies in MCI, whether or not memory performance lies below specific z-scores. This is supported by our preliminary biomarker analyses. However, further analyses with bigger samples are needed to corroborate these findings.

Mild cognitive impairment: a concept in evolution

The construct of mild cognitive impairment (MCI) has evolved over the past 10 years since the publication of the new MCI definition at the Key Symposium in 2003, but the core criteria have remained unchanged. The construct has been extensively used worldwide, both in clinical and in research settings, to define the grey area between intact cognitive functioning and clinical dementia. A rich set of data regarding occurrence, risk factors and progression of MCI has been generated. Discrepancies between studies can be mostly explained by differences in the operationalization of the criteria, differences in the setting where the criteria have been applied, selection of subjects and length of follow-up in longitudinal studies. Major controversial issues that remain to be further explored are algorithmic versus clinical classification, reliability of clinical judgment, temporal changes in cognitive performances and predictivity of putative biomarkers. Some suggestions to further develop the MCI construct include the tailoring of the clinical criteria to specific populations and to specific contexts. The addition of biomarkers to the clinical phenotypes is promising but requires deeper investigation. Translation of findings from the specialty clinic to the population setting, although challenging, will enhance uniformity of outcomes. More longitudinal population-based studies on cognitive ageing and MCI need to be performed to clarify all these issues.

The unbearable lightness of MCI

The title of this Editorial, with apologies to Milan Kundera (Kundera, 1985) implies no lack of gravitas in the concept of Mild Cognitive Impairment (MCI). Rather, it refers to the current definitions of MCI being somewhat free-floating, loosely anchored to diagnostic frameworks, and more conceptual than operational. In their defense, we cannot completely obliterate the flexibility clinicians need in order to exercise expert judgment and take individual patients’ circumstances into account when making clinical diagnoses. Further, it would be imprudent to prematurely codify diagnostic criteria for MCI; after all, we are still gathering basic information about the wide range of mildly impaired states that we encounter in different clinical settings and in the population at large.

Cognitive lifestyle jointly predicts longitudinal cognitive decline and mortality risk

Cognitive lifestyle measures such as education, occupation, and social engagement are commonly associated with late-life cognitive ability although their associations with cognitive decline tend to be mixed. However, longitudinal analyses of cognition rarely account for death and dropout, measurement error of the cognitive phenotype, and differing trajectories for different population sub-groups. This paper applies a joint latent class mixed model (and a multi-state model in a sensitivity analysis) that accounts for these issues to a large (n = 3,653), population-based cohort, Paquid, to model the relationship between cognitive lifestyle and cognitive decline. Cognition was assessed over a 20-year period using the Mini-Mental State Examination. Three cognitive lifestyle variables were assessed: education, mid-life occupation, and late-life social engagement. The analysis identified four latent sub-populations with class-specific longitudinal cognitive decline and mortality risk. Irrespective of the cognitive trajectory, increased social engagement was associated with a decreased mortality risk. High education was associated with the most favourable cognitive trajectory, and after adjusting for cognitive decline, with an increased mortality risk. Mid-life occupational complexity was also associated with more favourable trajectories but not with mortality risk. To realistically examine the link between cognitive lifestyle and cognitive decline, complex statistical models are required. This paper applies and compares in a sensitivity analysis two such models, and shows education to be linked to a compression of cognitive morbidity irrespective of cognitive trajectory. Furthermore, a potentially modifiable variable, late-life social engagement is associated with a decreased mortality risk in all of the population sub-groups.

Estimated maximal and current brain volume predict cognitive ability in old age

Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging.

The presence of behavioural and psychological symptoms and progression to dementia in the cognitively impaired older population

OBJECTIVE

Behavioural and psychological symptoms (BPS) are common in the older population and may be an indication of early dementia. We explored the predictive effect of the presence of BPS on the 2-year progression to dementia in a cognitively impaired population aged 65 years and over without dementia at baseline.

METHODS

Twelve symptoms were measured in 2024 participants without dementia at baseline as part of a population-based longitudinal study of ageing. The risk of progression to dementia was predicted in those with cognitive impairment for each individual BPS and using a BPS composite score.

RESULTS

Wandering and persecution were independently associated with progression to dementia after adjustment for socio-demographic factors, cognitive domains and other BPS. When stratifying by cognitive function, those with low cognition (MMSE 0-18) and 4 or more BPS were more likely to progress to dementia than those without BPS.

CONCLUSIONS

We have shown that some psychiatric symptoms are associated with increased short-term progression to dementia in those with low cognition. The predictive effect of BPS in dementia progression has implications for risk stratification of those at high risk of progression to dementia, along with memory impairment, other cognitive impairment and health variables.

Neuropathological profile of mild cognitive impairment from a population perspective

Whether the neuropathological profile of mild cognitive impairment (MCI) reflects an intermediate state between normal aging and dementia is not clear. Identifying which phenomena initiate disease and which occur secondary to the neuropathological process is important for targeted disease prevention. Current definitions of MCI include amnestic (aMCI), nonamnestic (nMCI), and multidomain (mMCI) subtypes. In an unbiased population-based cohort of brain donors, we have determined how many individuals fulfill these criteria in the period leading up to death [n=10 (5 multidomain MCI, 4 amnestic MCI, 1 nonamnestic MCI)]. All MCI cases were collapsed into 1 group and we tested whether their pathologic profile, including markers of Alzheimer disease (AD) and vascular disease (VD), is intermediate to individuals (matched for age, sex, and education) without cognitive impairment (n=20) or dementia (n=20). The main findings are of a significant linear trend in the odds of neuritic plaques (entorhinal/hippocampus), atrophy (hippocampal and cortical), infarcts, and small vessel disease (SVD) with increased cognitive impairment. Neuropathologically, MCI is complex, with 10% of MCI brains classified as normal, 10% as VD, 10% as AD, and 40% as mixed AD/VD, with the remaining showing other pathologies. Rather than pure pathologic changes, several different factors seem to contribute to the impairment of MCI. In MCI, both AD and non-AD pathology should be considered as possible intervention targets.

Active cognitive lifestyle is associated with positive cognitive health transitions and compression of morbidity from age sixty-five

BACKGROUND

Three factors commonly used as measures of cognitive lifestyle are education, occupation, and social engagement. This study determined the relative importance of each variable to long term cognitive health in those with and without severe cognitive impairment.

METHODS

Data came from 12,470 participants from a multi-centre population-based cohort (Medical Research Council Cognitive Function and Ageing Study). Respondents were aged 65 years and over and were followed-up over 16 years. Cognitive states of no impairment, slight impairment, and moderate/severe impairment were defined, based on scores from the Mini-Mental State Examination. Multi-state modelling was used to investigate links between component cognitive lifestyle variables, cognitive state transitions over time, and death.

RESULTS

Higher educational attainment and a more complex mid-life occupation were associated with a lower risk of moving from a non-impaired to a slightly impaired state (hazard ratios 0.5 and 0.8), but with increased mortality from a severely impaired state (1.3 and 1.1). More socially engaged individuals had a decreased risk of moving from a slightly impaired state to a moderately/severely impaired state (0.7). All three cognitive lifestyle variables were linked to an increased chance of cognitive recovery back to the non-impaired state.

CONCLUSIONS

In those without severe cognitive impairment, different aspects of cognitive lifestyle predict positive cognitive transitions over time, and in those with severe cognitive impairment, a reduced life-expectancy. An active cognitive lifestyle is therefore linked to compression of cognitive morbidity in late life.

Prediction of incident dementia: impact of impairment in instrumental activities of daily living and mild cognitive impairment-results from the German study on ageing, cognition, and dementia in primary care patients

OBJECTIVES

There is an increasing call for a stronger consideration of impairment in instrumental activities of daily living (IADL) in the diagnostic criteria of Mild Cognitive Impairment (MCI) to improve the prediction of dementia. Thus, the aim of the study was to determine the predictive capability of MCI and IADL impairment for incident dementia.

DESIGN

Longitudinal cohort study with four assessments at 1.5-year intervals over a period of 4.5 years.

SETTING

: Primary care medical record registry sample.

PARTICIPANTS

As part of the German Study on Ageing, Cognition, and Dementia in Primary Care Patients, a sample of 3,327 patients from general practitioners, aged 75 years and older, was assessed.

MEASUREMENTS

The predictive capability of MCI and IADL impairment for incident dementia was analysed using receiver operating characteristics, Kaplan-Meier survival analyses, and Cox proportional hazards models.

RESULTS

MCI and IADL impairment were found to be significantly associated with higher conversion to, shorter time to, and better predictive power for future dementia. Regarding IADL, a significant impact was particularly found for impairment in responsibility for one's own medication, shopping, and housekeeping, and in the ability to use public transport.

CONCLUSIONS

Combining MCI with IADL impairment significantly improves the prediction of future dementia. Even though information on a set of risk factors is required to achieve a predictive accuracy for dementia in subjects with MCI being clinically useful, IADL impairment should be a very important element of such a risk factor set.

Alzheimer and vascular neuropathological changes associated with different cognitive States in a non-demented sample

The state between aging with no cognitive impairment and dementia has become a major focus for intervention. The neuropathological and neurobiological correlates of this intermediate state are therefore of considerable interest, particularly from population representative samples. Here we investigate the neuropathological profile associated with different cognitive ability levels measured using strata defined by Mini Mental State Examination (MMSE) scores. One hundred and fifty one individuals were stratified into three cognitive groups including: non-, mildly, and moderately impaired at death. Alzheimer's disease, atrophy, and vascular pathologies were investigated. Mild impairment was associated with an increased risk of vascular pathologies including small vessel disease and lacunes. In contrast, the moderately impaired group showed a more extensive pattern of pathology, including tangles and neuritic plaques (entorhinal/hippocampus), atrophy (cortical and hippocampal), and vascular disease (small vessel disease, lacunes, and infarcts). In a population-based sample of older people, MMSE score defined strata are associated with multiple pathologies. The profile of AD and vascular changes becomes more complex with increased cognitive impairment and these changes are likely to constitute a major substrate for age associated cognitive impairment. The results highlight the need for rigorous investigation of both neurodegenerative and vascular risks factors in old age.

The reliability of assigning individuals to cognitive states using the Mini Mental-State Examination: a population-based prospective cohort study

Background

Previous investigations of test re-test reliability of the Mini-Mental State Examination (MMSE) have used correlations and statistics such as Cronbach's α to assess consistency. In practice, the MMSE is usually used to group individuals into cognitive states. The reliability of this grouping (state based approach) has not been fully explored.

Methods

MMSE data were collected on a subset of 2,275 older participants (≥ 65 years) from the population-based Medical Research Council Cognitive Function and Ageing Study. Two measurements taken approximately two months apart were used to investigate three state-based categorisations. Descriptive statistics were used to determine how many people remained in the same cognitive group or went up or down groups. Weighted logistic regression was used to identify predictive characteristics of those who moved group.

Results

The proportion of people who remained in the same MMSE group at screen and follow-up assessment ranged from 58% to 78%. The proportion of individuals who went up one or more groups was roughly equal to the proportion that went down one or more groups; most of the change occurred when measurements were close to the cut-points. There was no consistently significant predictor for changing cognitive group.

Conclusion

A state-based approach to analysing the reliability of the MMSE provided similar results to correlation analyses. State-based models of cognitive change or individual trajectory models using raw scores need multiple waves to help overcome natural variation in MMSE scores and to help identify true cognitive change.

An international perspective on advanced neuroimaging: cometh the hour or ivory tower?

Over the past five to ten years, neuroimaging capability for neurodegenerative diseases has made remarkable progress. However, debate remains as to the true clinical utility of these advanced and costly investigations. Not only is the place of these tests in diagnostic algorithms unclear, but the access to them varies both within and between countries. We sought to gather informed opinion from recognized leaders in the field who can combine both an academic and a clinical perspective on the use of neuroimaging in their own countries. Opinion is presented from Scotland, Argentina, the Czech Republic, France, the USA and Australia. The emerging consensus was one of ongoing caution. While in most countries there was a sense that the use of more advanced imaging techniques was growing, their hour has not yet cometh. However, these techniques, rather than falling from the Ivory Tower, should descend slowly step by step onto fertile and receptive clinics from where better clinical guidelines will emerge.

Should mild cognitive impairment be subtyped?

PURPOSE OF REVIEW

To review evidence on the validity and utility of recent approaches to subtyping late-life mild cognitive impairment.

RECENT FINDINGS

There is growing evidence that amnestic mild cognitive impairment is associated with biomarkers for Alzheimer's disease, while nonamnestic mild cognitive impairment maps more closely to cerebrovascular disease. The former is more likely to progress to dementia than the latter. Mild impairment in multiple cognitive domains appears to represent a more advanced disease state than single-domain impairment, and is more likely to progress to dementia. The cognitive subtypes have imprecise boundaries and have limited ecological validity. Approaches to subtyping that also incorporate biomarkers increase diagnostic specificity and have greater predictive value. However, these approaches have yet to be validated outside specialized memory clinic populations.

SUMMARY

Mild cognitive impairment as currently defined is still etiologically and prognostically heterogeneous, particularly outside specialty clinical settings. The objective of further subtyping is to delineate subgroups that are more clinically homogeneous. The current cognitive subtypes have some validity and utility but additional approaches should be explored so as to enhance these properties.