Prevalence of ageing-associated cognitive decline in an elderly population

Development of robust normative data for the neuropsychological assessment of Greek older adults

OBJECTIVE

Normative data for older adults may be tainted by inadvertent inclusion of undiagnosed individuals at the very early stage of a neurodegenerative process. To avoid this pitfall, we developed norms for a cohort of older adults without MCI/dementia at 3-year follow-up.

METHODS

A randomly selected sample of 1041 community-dwelling individuals (age ≥ 65) received a full neurological and neuropsychological examination on two occasions [mean interval = 3.1 (SD = 0.9) years].

RESULTS

Of these, 492 participants (Group 1; 65-87 years old) were without dementia on both evaluations (CDR=0 and MMSE ≥ 26); their baseline data were used for norms development. Group 2 (n = 202) met the aforementioned criteria only at baseline, but not at follow-up. Multiple linear regressions included demographic predictors for regression-based normative formulae and raw test scores as dependent variables for each test variable separately. Standardized scaled scores and stratified discrete norms were also calculated. Group 2 performed worse than Group 1 on most tests (p-values < .001-.021). Education was associated with all test scores, age with most, and sex effects were consistent with the literature.

CONCLUSIONS

We provide a model for developing sound normative data for widely used neuropsychological tests among older adults, untainted by potential early, undiagnosed cognitive impairment, reporting regression-based, scaled, and discrete norms for use in clinical settings to identify cognitive decline in older adults. Additionally, our co-norming of a variety of tests may enable intra-individual comparisons for diagnostic purposes. The present work addresses the challenge of developing robust normative data for neuropsychological tests in older adults.

Cognitive decline monitoring through a web-based application

Cognitive decline usually begins after individuals reach maturity, which is more evident in late adulthood. Rapid and constant cognitive screenings allow early detection of cognitive decline and motivate individuals to participate in prevention interventions. Due to accelerated technological advances, cognitive screening and training are now available to the layperson using electronic devices connected to the internet. Large datasets generated by these platforms provide a unique opportunity to explore cognitive development throughout life and across multiple naturalistic environments. However, such data collection mechanisms must be validated. This study aimed to determine whether the data gathered by commercial visuospatial and phonological working memory tests (CogniFit Inc., San Francisco, USA) confirm the well-established argument that age predicts cognitive decline. Data from 3,212 participants (2,238 females) who were 45 years old or older were analyzed. A linear regression analysis explored the relationship between age and working memory while controlling for gender, sleep quality, and physical activity (variables that are known to affect working memory). We found that age negatively predicts working memory. Furthermore, there was an interaction between age and gender for visuospatial working memory, indicating that although male participants significantly outperformed females, the relationship between age and working memory differs for females and males. Our results suggest that the computerized assessment of visuospatial and phonological working memory is sensible enough to predict cognitive functions in aging. Suggestions for improving the sensitivity of self-reports are discussed. Further studies must explore the nature of gender effects on cognitive aging.

Effects of adenosine A2A receptors on cognitive function in health and disease

Adenosine A2A receptors have been studied extensively in the context of motor function and movement disorders such as Parkinson's disease. In addition to these roles, A2A receptors have also been increasingly implicated in cognitive function and cognitive impairments in diverse conditions, including Alzheimer's disease, schizophrenia, acute brain injury, and stress. We review the roles of A2A receptors in cognitive processes in health and disease, focusing primarily on the effects of reducing or enhancing A2A expression levels or activities in animal models. Studies reveal that A2A receptors in neurons and astrocytes modulate multiple aspects of cognitive function, including memory and motivation. Converging evidence also indicates that A2A receptor levels and activities are aberrantly increased in aging, acute brain injury, and chronic disorders, and these increases contribute to neurocognitive impairments. Therapeutically targeting A2A receptors with selective modulators may alleviate cognitive deficits in diverse neurological and neuropsychiatric conditions. Further research on the exact neural mechanisms of these effects as well as the efficacy of selective A2A modulators on cognitive alterations in humans are important areas for future investigation.

A novel easy-to-use index to predict institutionalization and death in older population - a 10-year population-based follow-up study

BACKGROUND

Various indexes have been developed to estimate the risk for mortality, institutionalization, and other adverse outcomes for older people. Most indexes are based on a large number of clinical or laboratory parameters. An index based on only a few parameters would be more practical to use in every-day clinical practice. Our aim was to create an index to predict the risk for mortality and institutionalization with as few parameters as possible without compromising their predictive ability.

METHODS

A prospective study with a 10-year follow-up period. Thirty-six clinical and fourteen laboratory parameters were combined to form an index. Cox regression model was used to analyze the association of the index with institutionalization and mortality. A backward statistical method was used to reduce the number of parameters to form an easy-to-use index for predicting institutionalization and mortality.

RESULTS

The mean age of the participants (n = 1172) was 73.1 (SD 6.6, range 64‒97) years. Altogether, 149 (14%) subjects were institutionalized, and 413 (35%) subjects deceased during the follow-up. Institutionalization and mortality rates increased as index scores increased both for the large 50-parameter combined index and for the reduced indexes. After a backward variable selection in the Cox regression model, three clinical parameters remained in the index to predict institutionalization and six clinical and three laboratory parameters in the index to predict mortality. The reduced indexes showed a slightly better predictive value for both institutionalization and mortality compared to the full index.

CONCLUSIONS

A large index with fifty parameters included many unimportant parameters that did not increase its predictive value, and therefore could be replaced with a reduced index with only a few carefully chosen parameters, that were individually associated with institutionalization or death.

Lactobacillus plantarum TWK10 Attenuates Aging-Associated Muscle Weakness, Bone Loss, and Cognitive Impairment by Modulating the Gut Microbiome in Mice

In humans, aging is characterized by the progressive decline in biological, physiological, and psychological functions, and is a major risk factor in the development of chronic diseases. Therefore, the development of strategies aimed at attenuating aging-related disorders and promoting healthy aging is critical. In a previous study, we have demonstrated that Lactobacillus plantarum TWK10 (TWK10), a probiotic strain isolated from Taiwanese pickled cabbage, improved muscle strength, exercise endurance, and overall body composition in healthy humans. In this study, the effect of TWK10 on the progression of age-related impairments was investigated in mice. We found that TWK10 not only enhanced muscle strength in young mice, but also prevented the aging-related loss of muscle strength in aged mice, which was accompanied by elevated muscle glycogen levels. Furthermore, TWK10 attenuated the aging-associated decline in learning and memory abilities, as well as bone mass. Further analyses of gut microbiota using next-generation sequencing (NGS) of the 16S rRNA gene showed that the pattern of gut microbial composition was clearly altered following 8 weeks of TWK10 administration. TWK10-treated mice also experienced an increase in short-chain fatty acid (SCFA)-producing bacteria and higher overall levels of gut SCFA. Furthermore, TWK10 administration to some extent reversed the aging-associated accumulation of pathogenic bacterial taxa. In conclusion, TWK10 could be viewed as a potential therapeutic agent that attenuates aging-related disorders and provides health benefits by modulating the imbalance of gut microbiota.

Cross-sectional associations of tau protein biomarkers with semantic and episodic memory in older adults without dementia: A systematic review and meta-analysis

Pathological tau is suggested to play a role in cognitive deterioration in the preclinical phase of Alzheimer's disease. We investigated cross-sectional associations of tau burden with episodic and semantic memory performance in older adults without dementia. A systematic search in MEDLINE (via PubMed), PsychINFO, and Embase resulted in 24 eligible studies for meta-analysis. Tau burden was assessed using CSF, PET, or histopathological measures. All studies evaluated associations of tau with episodic memory: weighted effect sizes were -0.46 (95 % CI [-0.73; -0.20], p < .001) for episodic composite scores, -0.19 ([-0.36; -0.03], p = .024) for delayed word list recall, and -0.05 ([-0.14; 0.04], p = .257) for logical memory. Fourteen studies evaluated associations of tau with semantic memory: weighted effect sizes were -0.28 ([-0.52; -0.04], p = .023) for semantic composite scores, -0.06 ([-0.16; 0.03], p = .194) for semantic fluency, and 0.06 ([-0.06; 0.18], p = .319) for picture naming. Our findings indicate that tau burden related to both episodic and semantic memory impairment in older individuals without a diagnosis of mild cognitive impairment or manifest dementia, with episodic composite scores showing the strongest association with tau burden. Future potential lies in developing more sensitive scores to detect this subtle cognitive impairment, which could contribute to early identification of individuals in the preclinical phase of Alzheimer's disease, thereby improving early diagnosis and timely intervention.

Phosphate Brain Energy Metabolism and Cognition in Alzheimer's Disease: A Spectroscopy Study Using Whole-Brain Volume-Coil 31Phosphorus Magnetic Resonance Spectroscopy at 7Tesla

Introduction

Mitochondrial dysfunction is a neurometabolic hallmark signaling abnormal brain energy metabolism (BEM) targeted as a potential early marker of Alzheimer’s disease (AD). Advanced imaging technologies, such as ³¹phosphorus magnetic resonance spectroscopy (³¹P MRS) at ultra-high-field (UHF) magnetic strength 7T, provide sensitive phosphate-BEM (p-BEM) data with precision. The study’s first goal was to develop a methodology to measure phosphate energy and membrane metabolites simultaneously across the whole-brain using volume-coil ³¹P MRS at 7T in three groups-cognitively normal (CN), amnestic mild cognitive impairment (aMCI), and AD. The second aim investigated whether p-BEM markers in the four brain regions-frontal, temporal, parietal, and occipital were significantly different across the three groups. The final goal examined correspondence between the p-BEM markers and cognition in the three groups.

Methods

Forty-one participants (CN = 15, aMCI = 15, AD = 11) were enrolled and completed cognitive assessment and scan. The cognitive domains included executive function (EF), memory, attention, visuospatial skills, and language. The p-BEM markers were measured using energy reserve index (PCr/t-ATP), energy consumption index (intracellular_Pi/t-ATP), metabolic state indicator (intracellular_Pi/PCr), and regulatory co-factors [magnesium (Mg²⁺) and intracellular pH].

Results

Thirteen metabolites were measured simultaneously from the whole brain for all three group with high spectral resolution at UHF. In the aMCI group, a lower p-BEM was observed compared to CN group based on two markers, i.e., energy reserve (p = 0.009) and energy consumption (p = 0.05) indices; whereas in AD a significant increase was found in metabolic stress indicator (p = 0.007) and lower Mg²⁺ (p = 0.004) in the temporal lobes compared to aMCI using ANOVA between group analytical approach. Finally, using a linear mixed model, a significant positive correlation was found between Mg²⁺ and cognitive performance of memory (p = 0.013), EF (p = 0.023), and attention (p = 0.0003) in CN but not in aMCI or AD.

Conclusion

To our knowledge, this is the first study to show that it is possible to measure p-BEM in vivo with precision at UHF across the three groups. Moreover, the findings suggest that p-BEM may be compromised in aMCI even before an AD diagnosis, which in future studies should explore to examine whether this energy crisis contributes to some of the earliest neuropathophysiologic changes in AD.

A practical laboratory index to predict institutionalization and mortality - an 18-year population-based follow-up study

Background

Previously, several indexes based on a large number of clinical and laboratory tests to predict mortality and frailty have been produced. However, there is still a need for an easily applicable screening tool for every-day clinical practice.

Methods

A prospective study with 10- and 18-year follow-ups. Fourteen common laboratory tests were combined to an index. Cox regression model was used to analyse the association of the laboratory index with institutionalization and mortality.

Results

The mean age of the participants (n = 1153) was 73.6 (SD 6.8, range 64.0–100.0) years. Altogether, 151 (14.8%) and 305 (29.9%) subjects were institutionalized and 422 (36.6%) and 806 (69.9%) subjects deceased during the 10- and 18-year follow-ups, respectively. Higher LI (laboratory index) scores predicted increased mortality. Mortality rates increased as LI scores increased both in unadjusted and in age- and gender-adjusted models during both follow-ups. The LI did not significantly predict institutionalization either during the 10- or 18-year follow-ups.

Conclusions

A practical index based on routine laboratory tests can be used to predict mortality among older people. An LI could be automatically counted from routine laboratory results and thus an easily applicable screening instrument in clinical settings.

Factors Associated with the Prevalence of Cognitive Impairment in a Rural Elderly Cameroonian Population: A Community-Based Study in Sub-Saharan Africa

BACKGROUND/AIMS

With rising elderly populations, age-related health problems such as cognitive impairment and dementia are major public health concerns. We sought to assess the prevalence of cognitive impairment and associated factors in rural elderly Cameroonians.

METHODS

The Mini Mental State Examination was used to assess the cognitive function of participants randomly recruited during a house-to-house survey of the Batibo Health District.

RESULTS

The prevalence of cognitive impairment in our study was 33.3%. Increasing age, female gender, being single, a lack of formal education, and higher systolic blood pressure values were significantly and independently associated with cognitive impairment.

CONCLUSION

The identification of modifiable factors would inform evidence-based policy to decrease the health and social burdens of cognitive impairment and dementia in the elderly in rural Cameroon.

Correlates of Cognitive Impairment among Indian Urban Elders

BACKGROUND

Cognitive impairment among elderly is increasing owing to increases in life expectancy globally. The problem is multifactorial. The objective of the present paper was to study the correlates of cognitive impairment in an urban elderly population in India.

METHODS

A cross sectional study was conducted among 100 randomly selected urban elderly population. Data was collected upon household visits using a predesigned pretested questionnaire administered by a trained investigator. Measurements included cognitive function assessment using Mini Mental State Examination, depression assessment using Geriatric Depression Scale, blood pressure measurement and anthropometry. Cognitive impairment was defined at MMSE score <24. Logistic regression was done to identify independently associated factors with cognitive impairment.

RESULTS

Prevalence of cognitive impairment among elderly was 10%. Women had a higher prevalence than men. Higher age, no schooling, living single, lower weight, lower waist and hip ratios, difficulty in activities of daily living, poor self-reported health, bedridden and depression significantly associated with cognitive impairment. The independently associated factors upon logistic regression were increasing age, no schooling and bedridden status for past six months.

CONCLUSION

Although the current prevalence of cognitive impairment among Indian urban elderly is low, several associated factors exist in this population that may increase the burden in future. Geriatric health policy should address the modifiable risk factors to manage the problem of cognitive impairment and its consequent outcomes.

The Prevalence of Mild Cognitive Impairment in China: A Systematic Review

The aim of this study was to analyze the prevalence of mild cognitive impairment (MCI) among the aging population (60 years of age and above) in China. Epidemiological investigations on MCI in online Chinese journals were identified manually using the CQVIP, CNKI, and Wanfang databases. Articles from journals published in English were identified using PubMed and Web of Science. Original studies that included prevalence surveys of MCI were selected. Forty-eight relevant studies were included in the analysis, covering 22 provinces in China. Our results showed that the pooled prevalence of MCI in the older Chinese population was 14.71% (95% confidence interval [CI], 14.50-14.92%). The prevalence was 16.72% (95% CI, 15.68-17.71%) in clinical samples vs. 14.61% (95% CI, 14.40-14.83%) in nonclinical samples (χ2=16.60, P<0.01), and 15.20% (95% CI, 14.91-15.49%) in screened samples vs. 14.16% (95% CI, 13.85-14.46%) in diagnosed samples (χ2=22.11, P<0.01). People of older age, of female sex, or living in rural areas or western China were associated with a higher prevalence of MCI. The prevalence of MCI was high in Chinese older adults, and even higher in those who were older, female, or living in rural areas or western China. Future studies are recommended to address the prevalence of MCI in the other 12 provinces of China. Furthermore, diagnostic assessments should be included in the identification of MCI.

Machine-learning Support to Individual Diagnosis of Mild Cognitive Impairment Using Multimodal MRI and Cognitive Assessments

BACKGROUND

Understanding whether the cognitive profile of a patient indicates mild cognitive impairment (MCI) or performance levels within normality is often a clinical challenge. The use of resting-state functional magnetic resonance imaging (RS-fMRI) and machine learning may represent valid aids in clinical settings for the identification of MCI patients.

METHODS

Machine-learning models were computed to test the classificatory accuracy of cognitive, volumetric [structural magnetic resonance imaging (sMRI)] and blood oxygen level dependent-connectivity (extracted from RS-fMRI) features, in single-modality and mixed classifiers.

RESULTS

The best and most significant classifier was the RS-fMRI+Cognitive mixed classifier (94% accuracy), whereas the worst performing was the sMRI classifier (∼80%). The mixed global (sMRI+RS-fMRI+Cognitive) had a slightly lower accuracy (∼90%), although not statistically different from the mixed RS-fMRI+Cognitive classifier. The most important cognitive features were indices of declarative memory and semantic processing. The crucial volumetric feature was the hippocampus. The RS-fMRI features selected by the algorithms were heavily based on the connectivity of mediotemporal, left temporal, and other neocortical regions.

CONCLUSION

Feature selection was profoundly driven by statistical independence. Some features showed no between-group differences, or showed a trend in either direction. This indicates that clinically relevant brain alterations typical of MCI might be subtle and not inferable from group analysis.

Medicalising normality? Using a simulated dataset to assess the performance of different diagnostic criteria of HIV-associated cognitive impairment

Objective

The reported prevalence of cognitive impairment remains similar to that reported in the pre-antiretroviral therapy era. This may be partially artefactual due to the methods used to diagnose impairment. In this study, we evaluated the diagnostic performance of the HIV-associated neurocognitive disorder (Frascati criteria) and global deficit score (GDS) methods in comparison to a new, multivariate method of diagnosis.

Methods

Using a simulated ‘normative’ dataset informed by real-world cognitive data from the observational Pharmacokinetic and Clinical Observations in PeoPle Over fiftY (POPPY) cohort study, we evaluated the apparent prevalence of cognitive impairment using the Frascati and GDS definitions, as well as a novel multivariate method based on the Mahalanobis distance. We then quantified the diagnostic properties (including positive and negative predictive values and accuracy) of each method, using bootstrapping with 10,000 replicates, with a separate ‘test’ dataset to which a pre-defined proportion of ‘impaired’ individuals had been added.

Results

The simulated normative dataset demonstrated that up to ~26% of a normative control population would be diagnosed with cognitive impairment with the Frascati criteria and ~20% with the GDS. In contrast, the multivariate Mahalanobis distance method identified impairment in ~5%. Using the test dataset, diagnostic accuracy [95% confidence intervals] and positive predictive value (PPV) was best for the multivariate method vs. Frascati and GDS (accuracy: 92.8% [90.3–95.2%] vs. 76.1% [72.1–80.0%] and 80.6% [76.6–84.5%] respectively; PPV: 61.2% [48.3–72.2%] vs. 29.4% [22.2–36.8%] and 33.9% [25.6–42.3%] respectively). Increasing the a priori false positive rate for the multivariate Mahalanobis distance method from 5% to 15% resulted in an increase in sensitivity from 77.4% (64.5–89.4%) to 92.2% (83.3–100%) at a cost of specificity from 94.5% (92.8–95.2%) to 85.0% (81.2–88.5%).

Conclusion

Our simulations suggest that the commonly used diagnostic criteria of HIV-associated cognitive impairment label a significant proportion of a normative reference population as cognitively impaired, which will likely lead to a substantial over-estimate of the true proportion in a study population, due to their lower than expected specificity. These findings have important implications for clinical research regarding cognitive health in people living with HIV. More accurate methods of diagnosis should be implemented, with multivariate techniques offering a promising solution.

Mild cognitive impairment: prevalence and incidence according to different diagnostic criteria

Background

Although mild cognitive impairment is associated with an increased risk of developing dementia, there has been little work on its incidence and prevalence.

Aims

To report age-specific prevalence, incidence and predictive validities for four diagnostic concepts of mild cognitive impairment.

Method

A community sample of 1045 dementia-free individuals aged 75 years and over was examined by neuropsychological testing in a three-wave longitudinal study.

Results

Prevalence rates ranged from 3% to 20%, depending on the concept applied. The annual incidence rates applying different case definitions varied from 8 to 77 per 1000 person-years. Rates of conversion to dementia over 2.6 years ranged from 23% to 47%.

Conclusions

Mild cognitive impairment is frequent in older people. Prevalence, incidence and predictive validities are highly dependent on the diagnostic criteria applied.

Increased Hippocampal ProBDNF Contributes to Memory Impairments in Aged Mice

Memory decline during aging or accompanying neurodegenerative diseases, represents a major health problem. Neurotrophins have long been considered relevant to the mechanisms of aging-associated cognitive decline and neurodegeneration. Mature Brain-Derived Neurotrophic Factor (BDNF) and its precursor (proBDNF) can both be secreted in response to neuronal activity and exert opposing effects on neuronal physiology and plasticity. In this study, biochemical analyses revealed that increased levels of proBDNF are present in the aged mouse hippocampus relative to young and that the level of hippocampal proBDNF inversely correlates with the ability to perform in a spatial memory task, the water radial arm maze (WRAM). To ascertain the role of increased proBDNF levels on hippocampal function and memory we performed infusions of proBDNF into the CA1 region of the dorsal hippocampus in male mice trained in the WRAM paradigm: In well-performing aged mice, intra-hippocampal proBDNF infusions resulted in a progressive and significant impairment of memory performance. This impairment was associated with increased p-cofilin levels, an important regulator of dendritic spines and synapse physiology. On the other hand, in poor performers, intra-hippocampal infusions of TAT-Pep5, a peptide which blocks the interaction between the p75 Neurotrophin Receptor (p75NTR) and RhoGDI, significantly improved learning and memory, while saline infusions had no effect. Our results support a role for proBDNF and its receptor p75NTR in aging-related memory impairments.

Cognitive training modifies disease symptoms in a mouse model of Huntington's disease

Huntington's disease (HD) is an incurable neurodegenerative disorder which causes a triad of motor, cognitive and psychiatric disturbances. Cognitive disruptions are a core feature of the disease, which significantly affect daily activities and quality of life, therefore cognitive training interventions present an exciting therapeutic intervention possibility for HD. We aimed to determine if specific cognitive training, in an operant task of attention, modifies the subsequent behavioural and neuropathological phenotype of the Hdh(Q111) mouse model of HD. Three testing groups comprising both Hdh(Q111) mice and wildtype controls were used. The first group received cognitive training in an operant task of attention at 4months of age. The second group received cognitive training in a comparable non-attentional operant task at 4months of age, and the third group were control animals that did not receive cognitive training. All groups were then tested in an operant task of attention at 12months of age. Relative to naïve untrained mice, both wildtype and Hdh(Q111) mice that received cognitive training in the operant task of attention demonstrated an increased number of trials initiated, greater accuracy, and fewer 'time out' errors. A specific improvement in response time performance was observed in Hdh(Q111) mice, relative to naïve untrained Hdh(Q111) mice. Relative to the group that received comparable training in a non-attentional task, both wildtype and Hdh(Q111) mice that received attentional training demonstrated superior accuracy in the task and made fewer 'time out' errors. Despite significant behavioural change, in both wildtype and Hdh(Q111) mice that had received cognitive training, no significant changes in neuropathology were observed between any of the testing groups. These results demonstrate that attentional cognitive training implemented at a young age significantly improves attentional performance, at an older age, in both wildtype and Hdh(Q111) mice. Attentional cognitive training also improved motor performance in Hdh(Q111) mice, thus leading to the conclusion that cognitive training can improve disease symptoms in a mouse model of HD.

Safe driving and executive functions in healthy middle-aged drivers

The introduction of the point system driver's license in several European countries could offer a valid framework for evaluating driving skills. This is the first study to use this framework to assess the functional integrity of executive functions in middle-aged drivers with full points, partial points or no points on their driver's license (N = 270). The purpose of this study is to find differences in executive functions that could be determinants in safe driving. Cognitive tests were used to assess attention processes, processing speed, planning, cognitive flexibility, and inhibitory control. Analyses for covariance (ANCOVAS) were used for group comparisons while adjusting for education level. The Bonferroni method was used for correcting for multiple comparisons. Overall, drivers with the full points on their license showed better scores than the other two groups. In particular, significant differences were found in reaction times on Simple and Conditioned Attention tasks (both p-values < 0.001) and in number of type-III errors on the Tower of Hanoi task (p = 0.026). Differences in reaction time on attention tasks could serve as neuropsychological markers for safe driving. Further analysis should be conducted in order to determine the behavioral impact of impaired executive functioning on driving ability.

The Relieving Effects of BrainPower Advanced, a Dietary Supplement, in Older Adults with Subjective Memory Complaints: A Randomized, Double-Blind, Placebo-Controlled Trial

Subjective memory complaints (SMCs) are common in older adults that can often predict further cognitive impairment. No proven effective agents are available for SMCs. The effect of BrainPower Advanced, a dietary supplement consisting of herbal extracts, nutrients, and vitamins, was evaluated in 98 volunteers with SMCs, averaging 67 years of age (47-88), in a randomized, double-blind, placebo-controlled trial. Subjective hypomnesis/memory loss (SML) and attention/concentration deficits (SAD) were evaluated before and after 12-week supplementation of BrainPower Advanced capsules (n = 47) or placebo (n = 51), using a 5-point memory questionnaire (1 = no/slight, 5 = severe). Objective memory function was evaluated using 3 subtests of visual/audio memory, abstraction, and memory recall that gave a combined total score. The BrainPower Advanced group had more cases of severe SML (severity ⩾ 3) (44/47) and severe SAD (43/47) than the placebo group (39/51 and 37/51, < 0.05, < 0.05, resp.) before the treatment. BrainPower Advanced intervention, however, improved a greater proportion of the severe SML (29.5%)(13/44) (P < 0.01) and SAD (34.9%)(15/43)(P < 0.01) than placebo (5.1% (2/39) and 13.5% (5/37), resp.). Thus, 3-month BrainPower Advanced supplementation appears to be beneficial to older adults with SMCs.

Clinical and Sociodemographic Factors Associated with Cognitive Impairment and Neuroprotection in Diabetes Patients

The aim of this study is to analyze the potential impact of factors (clinical and demographic variables and comorbidities) associated with Diabetes Mellitus (DM) on certain mental processes related to cognitive impairment, with special attention to the analysis of parameters that define processing speed and executive function. Neuropsychological examination of elderly Spanish patients (N = 59, 33 females, Mage 70.98 years) diagnosed with DM, in addition to application of an ad hoc questionnaire to collect information on comorbidities and other relevant demographic variables. Based on a cross-sectional design, correlational analysis was carried out. Cognitive performance showed an inverse relationship to age and cardiopathology while years of schooling and regular physical activity appeared as neuroprotective factors. DM is an illness which, linked to other variables, can be regarded as a risk factor for the development of cognitive impairment. Certain factors (physical activity and cognitive stimulation) have the potential to mitigate this tendency. There is a need to further our understanding of the neurobiological mechanisms involved.

Endocrine factors, memory and perceptual capacities and aging in Asian men

BACKGROUND

This cross-sectional study examined the associations of hormones and age with short-term memory and perceptual capacity in 472 healthy Asian men.

METHODS

The symbol digit and digit span tests from the Swedish Performance Evaluation System were used to assess perceptual capacity and memory. Linear regression analyses with the stepwise method were carried out with the SPSS 21.0 package.

RESULTS

Age was associated with lower dehydorepiandrosterone sulphate (DHEA/S), insulin growth factor-1 (IGF-1), thyroxine (T4), testosterone (T), bioavailable T (BioT) and error rate (Err) but higher glucose (GLU), sex hormone binding globulin (SHBG), estradiol (E2) and retention time (RT). High GLU was associated with higher error rate, longer RT of the perceptual capacity domain and shorter digit span (DSpan) of the short-term memory domain. Higher insulin-like growth factor binding protein-3 (BP3) was associated with longer DSpan. High cortisol (Cor) was associated with higher Err, while high DHEA/S was associated with shorter RT. All other hormones from the adrenal, somatotrophic and gonadal were not significantly associated with cognition.

CONCLUSION

The findings suggest (1) a role for tighter control of blood glucose levels in cognitive decline with aging in men, (2) different hormones may be related to different parameters of cognition and "cognition" is not a unitary phenomenon and (3) further investigation of the potential for exogenous DHEA/S to slow cognitive decline in aging, especially as it relates to reaction time.

Cognitive impairment in individuals with low educational level and homogeneous sociocultural background

Prevalence studies of dementia and cognitive impairment in different cultures and environments are necessary.

Efficacy and Feasibility of Functional Upper Extremity Task-Specific Training for Older Adults With and Without Cognitive Impairment

BACKGROUND

Although functional task-specific training is a viable approach for upper extremity neurorehabilitation, its appropriateness for older populations is unclear. If task-specific training is to be prescribed to older adults, it must be efficacious and feasible, even in patients with cognitive decline due to advancing age.

OBJECTIVE

This cross-sectional study tested the efficacy and feasibility of upper extremity task-specific training in older adults, including those with lower cognitive scores.

METHODS

Fifty older adults (age 65-89 years) without any confounding neuromuscular impairment were randomly assigned to a training group or no-training group. The training group completed 3 days (dosage = 2250 repetitions) of a functional upper extremity motor task (simulated feeding) with their nondominant hand; the no-training group completed no form of training at all. Both groups' task performance (measured as trial time) was tested at pre- and posttest, and the training group was retested 1 month later. Efficacy was determined by rate, amount, and retention of training-related improvement, and compared across levels of cognitive status. Feasibility was determined by participants' tolerance of the prescribed training dose.

RESULTS

The training group was able to complete the training dose without adverse responses and showed a significant rate, amount, and retention of improvement compared with the no-training group. Cognitive status did not alter results, although participants with lower scores on the Montreal Cognitive Assessment were slower overall.

CONCLUSIONS

Task-specific training may be appropriate for improving upper extremity function in older adults, yet future work in older patients with specific neurological conditions is needed.

Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis

Background

Cognitive impairment, including dementia, is a major health concern with the increasing aging population. Preventive measures to delay cognitive decline are of utmost importance. Alzheimer’s disease (AD) is the most frequent cause of dementia, increasing in prevalence from <1% below the age of 60 years to >40% above 85 years of age.

Methods

We systematically reviewed selected modifiable factors such as education, smoking, alcohol, physical activity, caffeine, antioxidants, homocysteine (Hcy), n-3 fatty acids that were studied in relation to various cognitive health outcomes, including incident AD. We searched MEDLINE for published literature (January 1990 through October 2012), including cross-sectional and cohort studies (sample sizes > 300). Analyses compared study finding consistency across factors, study designs and study-level characteristics. Selecting studies of incident AD, our meta-analysis estimated pooled risk ratios (RR), population attributable risk percent (PAR%) and assessed publication bias.

Results

In total, 247 studies were retrieved for systematic review. Consistency analysis for each risk factor suggested positive findings ranging from ~38.9% for caffeine to ~89% for physical activity. Education also had a significantly higher propensity for “a positive finding” compared to caffeine, smoking and antioxidant-related studies. Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids. Estimated PAR% were particularly high for physical activity (PAR% = 31.9; 95% CI: 22.7-41.2) and smoking (PAR%=31.09%; 95% CI: 17.9-44.3). Overall, no significant publication bias was found.

Conclusions

Higher Hcy levels, lower educational attainment, and decreased physical activity were particularly strong predictors of incident AD. Further studies are needed to support other potential modifiable protective factors, such as caffeine.

Epidemiology of mild cognitive impairment in Brazil

With the worldwide increase in longevity and rising prevalence of cognitive disorders in the aged population, efforts have been made to characterize mild cognitive impairment (MCI) and its prevalence and/or incidence in a number of countries, given MCI may be a pre-dementia phase of degenerative conditions. The aim of this review was to retrieve the available data on the prevalence and incidence of mild cognitive impairment (MCI) in Brazil and compare these with rates found by studies conducted in other countries. The Pubmed and Scielo databases were searched using the following search terms: mild cognitive impairment, prevalence, incidence, including studies in both English and Portuguese languages. Only one study on MCI prevalence has been published in Brazil, reporting a prevalence rate of 6.1% and incidence of 13.2/1000 persons-year among those aged 60 years or over. Prevalence rates for other countries are also reported. The prevalence and incidence of MCI found in Brazil is similar to rates observed in other countries.

Longitudinal imaging pattern analysis (SPARE-CD index) detects early structural and functional changes before cognitive decline in healthy older adults

This article investigates longitudinal imaging characteristics of early cognitive decline during normal aging, leveraging on high-dimensional imaging pattern classification methods for the development of early biomarkers of cognitive decline. By combining magnetic resonance imaging (MRI) and resting positron emission tomography (PET) cerebral blood flow (CBF) images, an individualized score is generated using high-dimensional pattern classification, which predicts subsequent cognitive decline in cognitively normal older adults of the Baltimore Longitudinal Study of Aging. The resulting score, termed SPARE-CD (Spatial Pattern of Abnormality for Recognition of Early Cognitive Decline), analyzed longitudinally for 143 cognitively normal subjects over 8 years, shows functional and structural changes well before (2.3-2.9 years) changes in neurocognitive testing (California Verbal Learning Test [CVLT] scores) can be measured. Additionally, this score is found to be correlated to the [(11)C] Pittsburgh compound B (PiB) PET mean distribution volume ratio at a later time. This work indicates that MRI and PET images, combined with advanced pattern recognition methods, may be useful for very early detection of cognitive decline.

The prevalence of mild cognitive impairment about elderly population in China: a meta-analysis

BACKGROUND

Dementia has been a major public health problem and mild cognitive impairment is considered the pre-dementia syndrome in recent years. However, there has not yet been a systematic analysis of the prevalence of mild cognitive impairment in China.

OBJECTIVES

The aim of this study was to analyse the prevalence of mild cognitive impairment among the population aged 60  years and older in China.

METHODS

Epidemiological investigations on mild cognitive impairment in China published in journals were identified manually and online by using CBMDISK, ChongqingVIP database and CNKI database. Those reported in English journals were identified using MEDLINE. Selected studies had to describe an original study defined by strict screening and diagnlstic criteria. The fixed effects model or random effects model was employed according to statistical test for homogeneity.

RESULTS

Twenty-two studies were selected, the statistical information of which was collected for systematic analysis. The results showed that the pooled prevalence of MCI for the elderly population was 12.7% (95% CI: 9.7-16.5%). In eastern and western China, the prevalence of MCI was 9.6 and 14.7%, respectively. There was a higher prevalence of MCI in the illiterate elderly population than in those who received years of education.

CONCLUSIONS

The prevalence of MCI affected by sex, age,education, which was lower in eastern than that in western China.

National estimates of the prevalence of Alzheimer's disease in the United States

Several methods of estimating prevalence of dementia are presented in this article. For both Brookmeyer and the Chicago Health and Aging project (CHAP), the estimates of prevalence are derived statistically, forward calculating from incidence and survival figures. The choice of incidence rates on which to build the estimates may be critical. Brookmeyer used incidence rates from several published studies, whereas the CHAP investigators applied the incidence rates observed in their own cohort. The Aging, Demographics, and Memory Study (ADAMS) and the East Boston Senior Health Project (EBSHP) were sample surveys designed to ascertain the prevalence of Alzheimer's disease and dementia. ADAMS obtained direct estimates by relying on probability sampling nationwide. EBSHP relied on projection of localized prevalence estimates to the national population. The sampling techniques of ADAMS and EBSHP were rather similar, whereas their disease definitions were not. By contrast, EBSPH and CHAP have similar disease definitions internally, but use different calculation techniques, and yet arrive at similar prevalence estimates, which are considerably greater than those obtained by either Brookmeyer or ADAMS. Choice of disease definition may play the larger role in explaining differences in observed prevalence between these studies.

Is amnestic mild cognitive impairment a useful concept?

As the world’s population continues to age, the issues of age-related memory impairment become increasingly important and relevant to individual health and quality of life, as well as an increasing public health and societal concern. The concept of mild cognitive impairment (MCI) has emerged as a response to the desire and need to identify an indolent clinical condition that would reliably predict progression to dementia, particularly Alzheimer’s disease (AD). As a result of decades of research in the field of neurodegeneration, it is becoming increasingly evident that neurodegenerative diseases begin years before the onset of clinical symptoms, and that standard clinical practice may be relatively insensitive at identifying early neurodegenerative states. The MCI concept was developed to identify the clinical parameters that define the earliest stages of the neurodegenerative process. The essence of the MCI classification is that of mild but measurable cognitive changes indicating a predisposition to progression to dementia, prior to the onset of functional decline. MCI and, more specifically, amnestic MCI were initially proposed as pathological transitional states that ultimately progress to full blown AD. However, after more than a decade of observations, it has been found that MCI subjects do not uniformly progress to dementia or AD and may revert back to normal cognitive states. While the concept of MCI may represent a valid model for characterization of the earliest stages of dementia and for delineation of risk factors, the operational definition may not adequately convey the intended concepts, and as such should be viewed with caution. Additional modifications to the concept and its operationalization are suggested in order to better identify patients with incipient AD and to guide clinical and research practices.

Neuropsychiatric symptoms are associated with increased risks of progression to dementia: a 2-year prospective study of 321 Chinese older persons with mild cognitive impairment

BACKGROUND

studies have suggested that neuropsychiatric (NP) symptoms influence the development of dementia among older adults. But, the results are inconsistent and there is limited information about NP symptoms in population-based samples.

OBJECTIVE

to explore the association between NP symptoms and risk of cognitive decline in Chinese older persons residing in the community.

DESIGN

prospective study.

SETTING

community sample.

SUBJECTS

a total of 321 community-dwelling Chinese older persons aged 60 or over with mild cognitive impairment participated in the study.

METHODS

at baseline, each subject was assessed with Clinical Dementia Rating (CDR), Mini-Mental State Examination, list learning and delayed recall, and Category Verbal Fluency Test. Severity of NP symptoms was evaluated with Neuropsychiatric Inventory (NPI). Global cognitive status at the end of 2-year study period was determined by CDR.

RESULTS

at baseline, 40.5% of participants exhibited one or more NP symptoms (NPI total score ≥ 1). Night-time behaviours (22.1%), depression (16.8%), apathy (14.0%) and anxiety (12.8%) were the most common NP symptoms. At the end of 2-year follow-up, 27.5% of participants with depression at baseline developed dementia, compared with 14.8% of those without depression (χ² = 4.90, P= 0.03). Aberrant motor behaviour was also significantly associated with deterioration in cognition (χ² = 5.84, P= 0.02), although it was an infrequent occurrence. On logistic regression analysis, only depression at baseline was shown to be a risk factor for progression to dementia (OR= 2.40, 95% CI 1.05-5.46, P= 0.04).

CONCLUSION

depression in non-demented older persons may represent an independent dimension reflecting early neuronal degeneration. Further studies should be conducted to assess whether effective management of NP symptoms exerts beneficial effects on cognitive function.

Prevalence of aging-associated cognitive decline in an Italian elderly population: results from cross-sectional phase of Italian PRoject on Epidemiology of Alzheimer's disease (IPREA)

BACKGROUND AND AIMS

The prevalence of the preclinical phase of dementia varies greatly, according to the diagnostic criteria and assessment procedures applied. The purpose of this study was to estimate the prevalence of cognitive impairment according to the Aging-Associated Cognitive Decline (AACD) diagnostic criteria in an Italian elderly population.

METHODS

In a multicenter community-based prospective study, 4785 Italian subjects aged 65-84 years, randomly selected from the registries of 12 Italian municipalities, were assessed by personal and informant interviews, physical and neurological examinations and an extensive neuropsychological battery.

RESULTS

Of these older subjects, 274 (9.2%) fulfilled all the AACD criteria, whereas 561 (18.8%) fulfilled only 3 of them (AACD-3). When the two groups diagnosed according to AACD criteria (AACD and AACD- 3) were merged, the prevalence was 28.0% (28.3% for men, 27.6% for women). Two other groups of subjects were also identified: a) Subjects with Objective evidence of Cognitive Decline without cognitive complaints (OCD), 508 (17.0%), i.e., subjects with documented neuropsychological deficits, although neither subjects nor informants reported cognitive complaints; and b) Subjects with Cognitive Complaints without objective demonstrable cognitive deficits (CC), 44 (1.5%), i.e., subjects and/or informants reported cognitive complaints without evidence of neuropsychological deficits. Thus, taking into account the additional OCD group, a total of 1343 persons with cognitive impairment without dementia (45.0%) was identified.

CONCLUSIONS

On the basis of our results, we estimate that 45% of our population-based Italian sample aged 65-84 years had some kind of cognitive deficits without dementia.

Montreal Cognitive Assessment Arabic version: reliability and validity prevalence of mild cognitive impairment among elderly attending geriatric clubs in Cairo

AIM

Mild cognitive impairment (MCI) is a clinical label which includes elderly subjects with memory impairment and with no significant daily functional disability. MCI is an important target for Alzheimer's dementia prevention studies. Data on the prevalence and incidence of MCI varies greatly according to cultural difference. The first aim of this study was to assess the reliability and validity of Montreal Cognitive Assessment (MoCA) Arabic version in MCI detection. The second was to determine the prevalence of MCI among apparently healthy elderly people attending geriatric clubs in Cairo.

METHODS

In stage I reliability & validity of MoCA Arabic version were assessed in reference to Cambridge Cognitive Examination (CAMCOG). In stage II prevalence of MCI was estimated using Arabic MoCA among apparently healthy elderly attending geriatric clubs. These geriatric clubs were randomly selected from different regions in Cairo governorate.

RESULTS

Test-retest reliability data of the Arabic MoCA were collected approximately 35.0 +/- 17.6 days apart. The mean change in Arabic MoCA scores from the first to second evaluation was 0.9 +/- 2.5 points, and correlation between the two evaluations was high (correlation coefficient = 0.92, P < 0.001). The internal consistency of the Arabic MoCA was good, yielding a Cronbach's alpha on the standardized items of 0.83. In diagnosing mild cognitive impairment, the Arabic MoCA showed 92.3% sensitivity and 85.7% specificity. The prevalence of MCI among elderly subjects attending geriatric clubs in Cairo is 34.2% and 44.3% of healthy men and women, respectively.

CONCLUSION

Older age, female sex and less education are the independent risk factors for MCI among apparently healthy elderly subjects attending geriatric clubs in Cairo.

Prevalence and distribution of cognitive impairment no dementia (CIND) among the aged population and the analysis of socio-demographic characteristics: the community-based cross-sectional study

The epidemiology on "cognitive impairment no dementia" (CIND) and its natural history are of great importance for understanding the transition from normal aging to dementia. Epidemiologic studies of CIND, however, are limited in China. The goal of our study was to determine the prevalence and distribution of CIND in the aged population and analyze socio-demographic factors. To accomplish this, we performed cluster random sampling of 6192 people aged over 65 years in Taiyuan, a metropolitan city located in northern China. Socio-demographic factors were surveyed by self-administered questionnaires. Neuropsychologic testing consisting of the Mini-Mental State Examination, Boston Naming Test, Trail Making Tests A and B, Block Design, Rey Auditory Verbal Learning Test, Visual Reproduction, Logical Memory, letter and category fluency, the National Adult Reading Test, the Geriatric Depression Scale, and the "state" section of the State-Trait Anxiety Inventory was also obtained. Pearson chi statistics and odds ratio with 95% confidence intervals were used to identify the relationship between CIND and socio-demographic factors. Logistic regression modeling was undertaken to identify potential risk factors. Results showed that an overall prevalence of CIND was 9.70% (95% confidence intervals: 9.62%-9.77%). Univariate analyses showed that the prevalence of CIND differed significantly according to age, sex, education level, monthly household income, and marital status (P<0.01), but not by occupational achievement (P>0.05). In a multiple logistic regression analysis, age, sex, marital status, educational level, and occupation were significantly associated with increased risk for CIND (P<0.01). This study confirms the high prevalence of CIND among the elderly population of China, similar to previous epidemiologic studies in other countries. Nearly all socio-demographic characteristics are associated with CIND. The putative risk factors identified merit further study.

The prevalence of cognitive impairment with no dementia in older people: the Seoul study

OBJECTIVE

This study aimed to estimate prevalence of cognitive impairment with no dementia (CIND) in older people. It was conducted in an urban area of Korea, Seoul, and employed a two-stage design for case identification.

METHODS

Overall 643 persons aged 65 years and older participated and 217 persons sampled from the three levels of performance of MMSE underwent a second stage clinical evaluation. CIND was diagnosed when the global Clinical Dementia Rating (CDR) index was 0.5 and the Diagnostic and Statistical Manual of Mental Disorders, 4th edition diagnostic features of dementia were not satisfied. CIND cases without any apparent causes were classified as CIND of unidentified cause (CIND(uc)).

RESULTS

CIND prevalence ranged from 26.3% in persons aged 65-69 to 46.5% in persons aged 85 years and older. The age-standardized prevalence for overall CIND was 31.9% and for CIND(uc) 19.2%. The prevalences of CIND for the three severity grade were 15.8%, 9.7%, and 6.2% for CDR sum of boxes scores of 0.5, 1-1.5, and >or=2, respectively.

CONCLUSIONS

The prevalence of CIND in community-residing elderly is probably higher than previously reported. The results of this study are useful for assessments of present and future demands for healthcare services.

Mental stimulation, neural plasticity, and aging: directions for nursing research and practice

An unprecedented increase in the number of older adults and consequent age-related cognitive declines may negatively contribute to an already overwhelmed healthcare system. Many older adults report cognitive changes and express interest in methods to maintain cognitive functioning. Mental stimulation that consists of cognitively challenging activities is a means to facilitate neural plasticity, which can increase cognitive reserve and result in maintained or improved cognitive functioning. In addition, compensatory activities may provide mental stimulation that can improve cognitive functioning and increase cognitive reserve. Several mental stimulation (e.g., education, cognitive remediation therapy) and mental compensation (e.g., spaced retrieval method, method of loci) strategies are described in this article. Because nurses have a significant amount of direct contact with older adults, these strategies have important implications for nursing practice and research.

Follow-up of mild cognitive impairment and related disorders over four years in adults in their sixties: the PATH Through Life Study

AIMS

The study aimed to estimate incidence rates of mild cognitive impairment and related disorders, and conversion to dementia.

METHODS

The data are drawn from the PATH Through Life Study. Baseline assessment in 2001-2002 included 2,551 participants 60-64 years old with 2,222 participating in a 4-year follow-up. Those screened positive with a cognitive assessment received clinical assessment for diagnoses of mild cognitive disorders (MCD) or dementia using established clinical criteria. Prevalence and incidence rates for the cohort were estimated with predictive regression models.

RESULTS

Annual incidence of dementia was 0.25%. Prevalence of mild cognitive impairment was 4.2%, age-associated memory impairment was 2.4%, age-associated cognitive decline was 7.6%, mild neurocognitive disorders occurred in 12.9% and other cognitive disorders in 7.3%. Prevalence of any diagnosis of any MCD (Any-MCD) was 29.5% and the annual incidence rate for Any-MCD was 5.7%. Agreement for specific diagnoses between waves 1 and 2 was fair to poor (0-47.0%), but agreement for Any-MCD over 4 years was 89.0%.

CONCLUSION

MCD diagnoses do not predict dementia at a 4-year follow-up in young-old adults. Prevalence rates for MCD vary greatly depending on the criteria and time of assessment.

Anxiety symptoms and cognitive performance in later life: results from the longitudinal aging study Amsterdam

OBJECTIVES

This study investigates whether, and if so how, anxiety symptoms are related to cognitive decline in elderly persons and whether anxiety symptoms precede cognitive decline.

METHOD

Data were obtained from the Longitudinal Aging Study Amsterdam. Anxiety symptoms were measured with the Hospital Anxiety and Depression Scale. General cognitive functioning was measured with the Mini-Mental State Examination, episodic memory with the Auditory Verbal Learning Test, fluid intelligence with the Raven's Coloured Progressive Matrices and information processing speed with the coding task. Multilevel analyses were performed to investigate the relationship between anxiety symptoms and cognitive decline over 9 years, taking into account confounding variables.

RESULTS

Although not consistent across all dimensions of cognitive functioning, a curvilinear effect of anxiety on cognitive performance was found. Furthermore, we found that previous measurement of anxiety symptoms were not predictive of cognitive decline at a later time-point.

CONCLUSION

This study suggests that the effect of anxiety on cognition depends on the severity of the present anxiety symptoms with mild anxiety associated with better cognition, whereas more severe anxiety is associated with worse cognition. The effect of anxiety symptoms on cognitive functioning seems to be a temporary effect, anxiety is not predictive of cognitive decline.

Prevalence of cognitive impairment without dementia in the United States

BACKGROUND

Cognitive impairment without dementia is associated with increased risk for disability, increased health care costs, and progression to dementia. There are no population-based prevalence estimates of this condition in the United States.

OBJECTIVE

To estimate the prevalence of cognitive impairment without dementia in the United States and determine longitudinal cognitive and mortality outcomes.

DESIGN

Longitudinal study from July 2001 to March 2005.

SETTING

In-home assessment for cognitive impairment.

PARTICIPANTS

Participants in ADAMS (Aging, Demographics, and Memory Study) who were age 71 years or older drawn from the nationally representative HRS (Health and Retirement Study). Of 1770 selected individuals, 856 completed initial assessment, and of 241 selected individuals, 180 completed 16- to 18-month follow-up assessment.

MEASUREMENTS

Assessments, including neuropsychological testing, neurologic examination, and clinical and medical history, were used to assign a diagnosis of normal cognition, cognitive impairment without dementia, or dementia. National prevalence rates were estimated by using a population-weighted sample.

RESULTS

In 2002, an estimated 5.4 million people (22.2%) in the United States age 71 years or older had cognitive impairment without dementia. Prominent subtypes included prodromal Alzheimer disease (8.2%) and cerebrovascular disease (5.7%). Among participants who completed follow-up assessments, 11.7% with cognitive impairment without dementia progressed to dementia annually, whereas those with subtypes of prodromal Alzheimer disease and stroke progressed at annual rates of 17% to 20%. The annual death rate was 8% among those with cognitive impairment without dementia and almost 15% among those with cognitive impairment due to medical conditions.

LIMITATIONS

Only 56% of the nondeceased target sample completed the initial assessment. Population sampling weights were derived to adjust for at least some of the potential bias due to nonresponse and attrition.

CONCLUSION

Cognitive impairment without dementia is more prevalent in the United States than dementia, and its subtypes vary in prevalence and outcomes.

Early identification of Alzheimer's disease: what have we learned from mild cognitive impairment?

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline, functional disability, and neuropsychiatric symptoms. Initial diagnosis is often delayed to a point when there is significant neurodegenerative pathology and secondary downstream pathogenic sequelae. The disease should be diagnosed during its earliest stage, as this would likely represent an ideal therapeutic window for disease-modifying therapies. Despite recent research that has focused on defining the clinically identifiable at-risk phase that precedes AD, reliable criteria for identifying patients in the prodromal to incipient stages of AD remain elusive.

In addressing the prodrome of AD, it has been clearly recognized that there are age-inappropriate cognitive declines that fall short of meeting the criteria for dementia. Most broadly, patients in this category have been classified as cognitively impaired not demented (CIND). In epidemiological studies, it has been estimated that 19% to 37% of patients ≥65 years of age are CIND. Conditions within the taxonomy of CIND include age-associated memory impairment (AAMI), age-associated cognitive decline (AACD), and mild cognitive impairment (MCI) (Slide 1).

AAMI is defined psychometrically by memory test scores that are ≥1 standard deviation below scores of young healthy control patients. AACD is characterized by scores in any cognitive domain that are ≥1 standard deviation below age- and education-adjusted normal measures. MCI is identified by memory function at a level ≥1.5 standard deviations below age- and education-adjusted means. Of these three conditions, MCI has been investigated most thoroughly and is defined by a clinical phenotype.

Plasma trace elements and cognitive function in older men and women: the Rancho Bernardo study

OBJECTIVE

This study examines the sex-specific associations of plasma concentrations of iron, copper, and zinc with cognitive function in older community-dwelling adults.

DESIGN

Cross-sectional study.

SETTING

1988-92 follow-up clinic visit.

PARTICIPANTS

602 men and 849 women (average age=75 +/- 8 years) who were community-dwelling and not clinically demented.

MEASUREMENTS

Blood samples were assayed for trace elements and 12 cognitive function tests were administered. Sex-specific analyses were adjusted for age, education, alcohol consumption, smoking, exercise, and estrogen use in women.

RESULTS

Men and women differed significantly in education and alcohol intake (p's < 0.001), concentrations of plasma iron, copper and zinc (p's < 0.001) and scores on 11 of 12 cognitive function tests (p=0.04 to < 0.001). Regression analyses showed significant inverted U-shaped associations in men; both low and high iron levels were associated with poor performance on total and long-term recall and Serial 7's (p's=0.018, 0.042 and 0.004, respectively) compared to intermediate concentrations. In women, iron and copper concentrations had inverse linear associations with Buschke total, long and short-term recall and Blessed scores (p's < 0.05). Zinc was positively associated with performance on Blessed Items (p=0.008). Analyses comparing cognitive function using categorically defined mineral concentrations yielded similar sex specific results.

CONCLUSION

Optimal trace element concentrations may exist for optimal cognitive function in older adults, and these levels may differ by sex and cognitive function domain.

Cognitive impairment: classification and open issues

Several clinically-defined cognitive impairment syndromes, with differing diagnostic criteria and nomenclature, have been proposed to describe nondisabling symptomatic cognitive deficits. Incidence and prevalence rates vary as a result of different diagnostic criteria and sampling procedures across studies. The incidence rates of cognitive impairment increase with age; but no consistent data have been reported on the association with family history, age, sex, education, Apo E4 genotype, depression, and other traditional risk factors for dementia. Several studies have suggested that most patients with cognitive impairment clinically defined will progress to Alzheimer Disease (AD), but rates of conversion vary widely among studies. This review summarizes existing definitions and related epidemiological data.

The critical period hypothesis: can it explain discrepancies in the oestrogen-cognition literature?

Although there is compelling evidence from small randomised controlled trials and cross-sectional studies indicating that oestrogen helps to protect against cognitive ageing in women, the findings of the large, Women's Health Initiative Memory Study failed to support the earlier findings. The attempt to resolve these discrepancies led to the formulation of the Critical Period Hypothesis which holds that oestrogen has maximal protective benefits on cognition in women when it is initiated closely in time to a natural or surgical menopause but not when treatment is begun decades after the menopause. This article reviews the evidence from basic neuroendocrinology, from animal behavioural studies and from human studies that supports the critical period hypothesis. In view of the promise of this hypothesis and its considerable clinical implications, a direct test of its validity is warranted.

Testosterone and cognitive function: current clinical evidence of a relationship

BACKGROUND

Testosterone levels decline as men age, as does cognitive function. Whether there is more than a temporal relationship between testosterone and cognitive function is unclear. Chemical castration studies in men with prostate cancer suggest that low serum testosterone may be associated with cognitive dysfunction. Low testosterone levels have also been observed in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). This paper reviews the current clinical evidence of the relationship between serum testosterone levels and cognitive function in older men.

METHODS

A systematic literature search was conducted using PubMed and EMBASE to identify clinical studies and relevant reviews that evaluated cognitive function and endogenous testosterone levels or the effects of testosterone substitution in older men.

RESULTS

Low levels of endogenous testosterone in healthy older men may be associated with poor performance on at least some cognitive tests. The results of randomized, placebo-controlled studies have been mixed, but generally indicate that testosterone substitution may have moderate positive effects on selective cognitive domains (e.g. spatial ability) in older men with and without hypogonadism. Similar results have been found in studies in patients with existing AD or MCI.

CONCLUSIONS

Low endogenous levels of testosterone may be related to reduced cognitive ability, and testosterone substitution may improve some aspects of cognitive ability. Measurement of serum testosterone should be considered in older men with cognitive dysfunction. For men with both cognitive impairment and low testosterone, testosterone substitution may be considered. Large, long-term studies evaluating the effects of testosterone substitution on cognitive function in older men are warranted.

The state of mental health in old-age across the 'old' European Union-- a systematic review

OBJECTIVE

The paper provides the first syllabus on the prevalence of mental disorders in old-age focusing on surveys conducted in the 15 countries, which comprised the 'old' European Union.

METHOD

A systematic search of the literature published from 1990 onwards was conducted.

RESULTS

Mental disorders in old-age are common. The most serious threats to mental health in old-age are posed by dementia and depression. It is a clear cut finding that dementia exponentially increases with age. The basic issue of whether depression increases or decreases with age remains unsolved. Databases on substance use, mild cognitive impairment, psychotic syndromes, anxiety, and somatoform disorders in old-age are much smaller, making conclusions difficult to draw.

CONCLUSION

Numerous questions in the field remain to be answered. Concerted action is needed to produce comparable data across Europe.

Assessment of cognitive status in the elderly using telephone interviews

OBJECTIVE

To examine the feasibility to assess cognitive status in the elderly using telephone interviews.

RESEARCH DESIGN AND METHODS

From January to December 2003, 740 participants of the ongoing Heidelberg longitudinal study (HeiDE) aged 70 years or more were eligible for a telephone interview on cognitive status. Validated instruments to assess cognitive status, including the Telephone Interview of Cognitive Status (TICS) and the East Boston Memory Test (EBMT, immediate and delayed recall), the Verbal Fluency Test, the HAWIE-"Vocabulary Test" and the HAWIE-"General Knowledge", a prospective memory test, and a digit span backwards-test were translated into German, if applicable.

RESULTS

Out of 740 participants at the age of 70 or older, 473 participants were interviewed (64.9%). The total score of the TICS (maximum=best: 41) ranged from 21 to 40 (mean 33.5, SD 3.1; median 34.0). The EBMT scores (immediate recall; maximum=best: 12) ranged from 4 to 12 (mean 9.2, SD 1.7; median 9.0).

CONCLUSIONS

Cognitive status could be successfully assessed by telephone interview in elderly participants of an ongoing population-based cohort study. Specifically, some of the tests showed pronounced variability allowing cross-sectional analyses whereas others seem more valuable for longitudinal assessment.

The impact of change in cognitive functioning and cognitive decline on disability, well-being, and the use of healthcare services in older persons. Results of Longitudinal Aging Study Amsterdam

The study investigated the impact of change in cognitive functioning and cognitive decline on disability, well-being, and the use of healthcare services among older persons in the Longitudinal Aging Study Amsterdam (LASA). Data were collected from 1,349 subjects, aged 65-85 years, who had scores of 24 and higher on the Mini-Mental State Examination (MMSE) at baseline, over a period of 6 years in three waves. The results indicate that cognitive decline and changes in cognitive functioning in older persons who were either not impaired or only mildly cognitively impaired at baseline have an impact on disability, well-being, and the use of healthcare services. With the aging of the population, the number of persons with cognitive impairment is likely to increase, and appropriate services should be available to them.