Subclinical cognitive impairment: epidemiology and clinical characteristics

Cross-Cultural Adaptation and Spanish Validation of the Computerized Information Processing Assessment Battery (COGNITO)

INTRODUCTION

Mild cognitive impairment (CI) has an exponential increase in its prevalence and causes functional deficits and dependence. Its early detection allows for timely treatment and greater therapeutic efficacy. However, mild cognitive impairment (MCI) is currently underdiagnosed. Although recent decades have seen a rise in computerized instruments for the detection and early diagnosis of MCI, showing numerous advantages over the classic paper-and-pencil methods, such as standardized stimulus presentation. However, their limitations include the use of self-administered application without professional supervision. Few of these instruments have Spanish-adapted versions.

OBJECTIVE

To translate, adapt, and validate the computerized Information Processing Assessment Battery (COGNITO) battery in the Spanish population and to develop a portable administration system that facilitates its application in different settings. COGNITO was then administered to 232 Spanish participants (18-89 years) without cognitive impairment, after which preliminary normative data were obtained.

RESULTS

Strong positive correlations were found between the main cognitive domains assessed by COGNITO and the variables of age, educational level, and MEC score. The gender variable only correlated with visuospatial skills, with men outperforming women. The test-retest correlations conducted after 4 weeks with 89 participants revealed adequate reliability coefficients ranging between.63 and.66 (visuospatial skills = 0.35). Internal consistency coefficients were satisfactory in Attention-Executive Functions and Memory domains.

CONCLUSIONS

The Spanish adaptation of COGNITO shows adequate psychometric characteristics of validity and reliability. The preliminary normative data provided may contribute to the early detection of cognitive impairments associated with both normal aging and various types of neurological pathology. This tool has great utility and versatility for neuropsychological practice.

Cognitive and Mood Effect of Alpha-Lipoic Acid Supplementation in a Nonclinical Elder Sample: An Open-Label Pilot Study

BACKGROUND

Memory disorders are common among elder people, and nonclinical cognitive decline is commonly experienced with age. Preclinical investigations have explored the possible role of alpha-lipoic acid (ALA), a known antioxidant compound abundant in vegetables and animal tissues, in reducing oxidative stress in the aging brain and preventing cognitive decline. However, clinical evidence is limited, and the few existing results are contrasting. In addition, while most of the existing trials have been focused on the effects of ALA administration in Alzheimer's disease (AD) or other types of dementia, studies evaluating its effects on nonclinical elder population are still missing.

METHODS

In the present open-label, pilot study, fifteen elder patients (mean age: 84.5 ± 5.77) received ALA at a daily dose of 600 mg/day for 12 weeks. General cognitive function, executive function, and mood symptom assessment were carried out at baseline and at the endpoint.

RESULTS

Overall, ALA administration was generally well-tolerated (only one dropout due to gastrointestinal side effects). However, no statistically significant effects either on cognitive function, executive function, or mood were found.

CONCLUSIONS

Despite several limitations, our study found no evidence of positive effects on cognition and mood after ALA administration in elder people without the diagnosis of AD or cognitive impairment. Further clinical trials are needed to better investigate ALA effectiveness on cognition and mood in elder subjects.

Cognitive impairment in patients with rheumatoid arthritis: A systematic review and meta-analysis

OBJECTIVE

An increasing number of studies have demonstrated cognitive impairment in patients with rheumatoid arthritis (RA). The literature indicates many factors play an important role in this clinical problem, such as the severity of depressive symptoms and the treatment used. The aim of this study was to systematically review studies comparing cognitive functioning between healthy participants and RA patients and to determine both the severity and potential moderators of cognitive impairment.

METHODS

For this purpose, 16 studies that fulfilled all selection criteria were carefully selected. Altogether, 921 patients with RA (812 women and 109 men) and 700 controls participated in these studies. Due to the inability to perform a network meta-analysis, it was decided to determine the effect sizes for studies which used the same measurement methods.

RESULTS

The analysis demonstrated greater impairment of cognitive functioning in patients with RA than in healthy controls, with effect sizes ranging from small to large, depending on the assessment method used in the study.

CONCLUSIONS

The study pinpoints potential biases, lack of replication, and inconsistencies in reporting data as possible confounding factors and suggests further recommendations for assessment methods, research directions and clinical implications.

CLINICAL TRIAL REGISTRATION

Not applicable.

Predementia constructs: Mild cognitive impairment or mild neurocognitive disorder? A narrative review

BACKGROUND

Predementia is a heuristic umbrella concept to classify older adults with cognitive impairment who do not suffer dementia. Many diagnostic entities have been proposed to address this concept, but most of them have not had widespread acceptance.

AIMS

To review clinical definitions, epidemiologic data (prevalence, incidence) and rate of conversion to dementia of the main predementia constructs, with special interest in the two most frequently used: mild cognitive impairment (MCI) and minor neurocognitive disorder (miNCD).

METHODS

We have selected in three databases (MEDLINE, Web of Science and Google scholar) the references from inception to 31 December 2019 of relevant reviews, population and community-based surveys, and clinical series with >500 participants and >3 years follow-up as the best source of evidence.

MAIN RESULTS

The history of predementia constructs shows that MCI is the most referred entity. It is widely recognized as a clinical syndrome harbinger of dementia of several etiologies, mainly MCI due to Alzheimer's disease. The operational definition of MCI has shortcomings: vagueness of its requirement of "preserved independence in functional abilities" and others. The recent miNCD construct presents analogous difficulties. Current data indicate that it is a stricter predementia condition, with lower prevalence than MCI, less sensitivity to cognitive decline and, possibly, higher conversion rate to dementia.

CONCLUSIONS

MCI is a widely employed research and clinical entity. Preliminary data indicate that the clinical use of miNCD instead of MCI requires more scientific evidence. Both approaches have common limitations that need to be addressed.

Exaggerated reaction to novelty as a predictor of incipient cognitive decline among community-dwelling older adults

OBJECTIVE

The ability to detect covert markers of incipient cognitive decline among older adults before cognitive decline becomes overtly evident on traditional cognitive tests represents an important topic of research. Exaggerated reactions to novelty, reflected in novelty-induced increases in action planning latencies ("novelty effect"; NE) and low openness to experience (openness), have been previously associated with incipient cognitive decline among older adults who appeared cognitively normal at baseline. The purposes of the present study were to extend prior research on the utility of these markers by examining whether (a) NE and openness each predict cognitive change uniquely, and (b) whether these indices predict cognitive change above and beyond measures of memory, executive functions, processing speed/efficiency, premorbid IQ, and depressive symptoms.

METHOD

Sixty-one cognitively normal community-dwelling older adults were administered a battery of tests assessing the relevant constructs at baseline and one-year follow up. Changes in cognitive status were assessed using the Demetia Rating Scale, 2nd Edition, NE was assessed using the Push-Turn-Taptap task (an electronic motor sequence learning task), and openness using the NEO Personality Inventory-Revised. The Test of Premorbid Functioning, and subtests from Repeatable Battery for the Assessment of Neuropsychological Status, Delis-Kaplan Executive Function System, and Wechsler Adult Intelligence Scale, 4th Edition, were used for additional assessment of baseline cognition. Depressive symptoms were assessed using the Geriatric Depression Scale.

RESULTS

Results confirmed our hypothesis that both NE and openness contribute to prediction of cognitive change beyond baseline cognition and depressive symptoms, but none of the covariates (i.e., depression, executive functions, processing efficiency, or memory) themselves contributed to the model. NE and openness each contributed unique variance and were independent of each other.

CONCLUSIONS

Openness and NE have the potential to provide evidence-based methods for estimating risk of future cognitive change in persons with currently normal standardized test scores.

Effects of white matter integrity and brain volumes on late life depression in the Framingham Heart Study

BACKGROUND

It is unclear whether brain white matter hyperintensities (WMHI) causes or is a result of late life depression. We used the Framingham Heart Study offspring to examine whether indices of brain aging are related to incident depression in the elderly.

METHODS

The Center for Epidemiologic Studies Depression Scale (CES-D) was administered along with a brain MRI scan at baseline and was re-administered (n = 1212) at an average 6.6 + 0.6 year follow-up. The outcomes (i) change in CES-D scores from baseline; (ii) depression defined as CES-D ≥16; (iii) severe depression defined as CES-D ≥21; and (iv) CES-D cutoff scores and/or on antidepressant were used.

RESULTS

Among those who did not have depression at baseline, 9.1% (n = 110) developed depression, 4.0% (n = 48) developed severe depressive symptoms, and 11.1% (n = 135) were put on antidepressants. When depressive symptoms only was the outcome, we found that baseline WMHI was positively associated with change in CES-D scores and that those with an extensive WMHI at baseline had a high risk of developing severe depressive symptoms; the relationship was strengthened in the absence of cardiovascular diseases. In contrast, when depressive symptoms or taking antidepressant was the outcome, larger total cerebral brain volume and temporal lobe brain volume, but not WMHI, were negatively associated with the development of depression.

CONCLUSIONS

Brain WMHI is a probable risk factor for vascular depression in the elderly. The depression outcomes with and without antidepressant were related to different brain pathologies. Copyright © 2016 John Wiley & Sons, Ltd.

Amyloid-associated depression and ApoE4 allele: longitudinal follow-up for the development of Alzheimer's disease

BACKGROUND

Amyloid-associated depression is associated with cognitive impairment cross sectionally. This follow-up study was to determine the relationship between amyloid-associated depression and the development of Alzheimer's disease (AD).

METHODS

Two hundred and twenty three subjects who did not have dementia at baseline were given a repeat cognitive evaluation for incident AD. Depression was defined by having a Center for Epidemiological Studies Depression (CES-D) score ≥ 16, and non-amyloid vs. amyloid-associated depression by having a low vs. high plasma amyloid-β peptide 40 (Aβ40)/Aβ42 ratio. Apolipoprotein E (ApoE) genotype was determined, and antidepressant usage was documented.

RESULTS

Fifteen subjects developed AD (7%) after an average follow-up time of 6.2 years. While none of those with non-amyloid depression developed AD, 9% of those with amyloid-associated depression developed AD. Further, among those with amyloid-associated depression, ApoE4 carriers tended to have a higher risk of AD than ApoE4 non-carriers (40% vs. 4%, p = 0.06). In contrast, 8% of those who did not have depression at baseline developed AD, but ApoE4 carriers and non-carriers did not show a difference in the AD risk. After adjusting for age, the interaction between ApoE4 and amyloid-associated depression (β = +0.113, SE = 0.047, P = 0.02) and the interaction between ApoE4 and antidepressant use (β = +0.174, SE = 0.064, P = 0.007) were associated with the AD risk.

CONCLUSIONS

Amyloid-associated depression may be prodromal depression of AD especially in the presence of ApoE4. Future studies with a larger cohort and a longer follow-up are warranted to further confirm this conclusion.

Depression and plasma amyloid beta peptides in the elderly with and without the apolipoprotein E4 allele

Depression associated with low plasma amyloid-beta peptide 42 (Abeta42) leading to a high ratio of Abeta40/Abeta42, a biomarker of Alzheimer disease (AD), may represent a unique depression subtype. The relationship between low plasma Abeta42 in depression and the major risk factor of AD, apolipoprotein E4 (ApoE4), is unknown. With the goal of clarifying this relationship, we analyzed 1060 homebound elders with ApoE characterization and depression status in a cross-sectional study. Plasma Abeta40 and Abeta42 were measured, and cognition were evaluated. In the absence of the ApoE4 allele, depressed subjects had lower plasma Abeta42 [median (Q1, Q3): 17.1 (11.6, 27.8) vs. 20.2 (12.9, 32.9) pg/mL, P=0.006], a higher Abeta40/Abeta42 ratio [median (Q1, Q3): 7.1 (4.6, 11.3) vs. 6.9 (3.4, 9.7), P=0.03], and lower cognitive function (mean+/-SD of Mini-Mental State Examination: 24.5+/-3.1 vs. 25.5+/-3.3, P<0.0001) than those without depression. In contrast, these relationships were not observed in the presence of ApoE4. Instead, regardless the depression status ApoE4 carriers had lower plasma Abeta42 and a higher Abeta40/Abeta42 ratio than non-ApoE4 carriers. Using multivariate logistic regression, it was found that depression was not associated with ApoE4 allele, but with the interaction between plasma Abeta42 and ApoE4 (odds ratio=3.94, 95% confidence interval=1.50, 10.33, P=0.005), denoting low plasma Abeta42 in the absence of ApoE4. Both ApoE4 carriers and non-ApoE4 carriers with depression had lower Abeta42 and a higher Abeta40/Abeta42 ratio in plasma compared with non-ApoE4 carriers without depression in the homebound elderly. As a combination of low plasma Abeta42 and high plasma Abeta40 has been shown to increase the risk of AD in 2 large cohort studies, amyloid-associated depression shown in this study may suggest a risk factor of AD in the absence of ApoE4.

Serum brain-derived neurotrophic factor is associated with cognitive function in healthy older adults

Cognitive decline is common in older adults, even in the absence of significant medical or neurological conditions. Recent work implicates serum levels of brain-derived neurotrophic factor in age-related cognitive decline, though no study has directly examined this possibility. A total of 35 older adults without neurological history underwent fasting blood draw and completed a brief neuropsychological test battery during a single session. After adjusting for demographic and medical confounds, higher serum brain-derived neurotrophic factor levels were associated with better performance on the Mini-Mental State Examination (r = .36) and short form of the Boston Naming Test (r = .39). These findings extend work from Alzheimer disease and vascular dementia samples and indicate that higher brain-derived neurotrophic factor levels are associated with better neuropsychological function in healthy older adults. The exact mechanisms for this relationship are unknown and require further examination.

Mild cognitive impairment in the general population: occurrence and progression to Alzheimer disease

OBJECTIVES

Our aims were to 1) detect the occurrence of three mild cognitive impairment (MCI) subtypes in the general population; 2) identify cases of cognitive impairment which are not detected by current operational criteria for MCI and; 3) determine the predictive value of the subtypes for identifying future Alzheimer disease (AD).

DESIGN

Three-year prospective study.

SETTING

Population-based Swedish study, the Kungsholmen Project.

PARTICIPANTS

Three hundred seventy-nine nondemented older adults aged 75-95.

MEASUREMENTS

Standard plus modified MCI criteria were applied at baseline. In the modified definitions, the requirement for normal general cognition was removed. A category for persons without MCI who had only global cognitive deficits was added. Three-year progression to AD was assessed (DSM-III-R criteria).

RESULTS

Occurrence per 100 nondemented persons of MCI-amnestic, MCI-multidomains, and MCI-single-nonmemory was 2.1%, 1.8%, and 7.2%, respectively. When applying modified definitions for MCI-amnestic and MCI-multidomains, the occurrence almost doubled. Seven percent of the sample had impairment on a global cognitive task but performed at normal levels on all other domain-specific tasks. MCI-multidomains showed the highest progression to AD (hazard ratio [HR]: 23.6, 9.3-60.1). MCI-amnestic reached similar predictivity only when using the modified definition (HR: 17.9, 6.8-46.9). Even participants without MCI who had only global deficits had a ninefold risk of AD (HR: 9.1, 2.8-29.4).

CONCLUSIONS

Two-thirds of MCI-multidomains, but only half of MCI-amnestic progress to AD. The standard MCI criteria failed to identify those people with global cognitive deficits who have, however, a high risk of progressing to AD.

Amyloid-associated depression: a prodromal depression of Alzheimer disease?

CONTEXT

A high ratio of plasma amyloid-beta peptide 40 (Abeta(40)) to Abeta(42), determined by both high Abeta(40) and low Abeta(42) levels, increases the risk of Alzheimer disease. In a previous study, we reported that depression is also associated with low plasma Abeta(42) levels in the elderly population.

OBJECTIVE

To characterize plasma Abeta(40):Abeta(42) ratio and cognitive function in elderly individuals with and without depression.

DESIGN

Cross-sectional study.

SETTING

Homecare agencies.

PARTICIPANTS

A total of 995 homebound elderly individuals of whom 348 were defined as depressed by a Center for Epidemiological Studies Depression score of 16 or greater.

MAIN OUTCOME MEASURES

Cognitive domains of memory, language, executive, and visuospatial functions according to levels of plasma Abeta(40) and Abeta(42) peptides.

RESULTS

Subjects with depression had lower plasma Abeta(42) levels (median, 14.1 vs 19.2 pg/mL; P = .006) and a higher plasma Abeta(40):Abeta(42) ratio (median, 8.9 vs 6.4; P < .001) than did those without depression in the absence of cardiovascular disease and antidepressant use. The interaction between depression and plasma Abeta(40):Abeta(42) ratio was associated with lower memory score (beta = -1.9, SE = 0.7, P = .006) after adjusting for potentially confounders. Relative to those without depression, "amyloid-associated depression," defined by presence of depression and a high plasma Abeta(40):Abeta(42) ratio, was associated with greater impairment in memory, visuospatial ability, and executive function; in contrast, nonamyloid depression was not associated with memory impairment but with other cognitive disabilities.

CONCLUSION

Amyloid-associated depression may define a subtype of depression representing a prodromal manifestation of Alzheimer disease.

Decline in verbal memory in non-demented older adults

Decline in memory function was detected in 30% of healthy community-dwelling elderly over 6 years using a task assessing delayed word list recall. Individuals with memory decline over time also demonstrated relative deficits on additional tasks of memory and learning, a task of working memory and executive function, and on a verbal (category) fluency task at their most recent assessment. These relative deficits in the performance of individuals with memory decline cannot be explained by age-related changes, education, intelligence, mood, health-related factors, or the individuals' APOE epsilon 4 status. Decline in memory performance did not result in greater complaints of cognitive difficulties when compared with normal elderly, nor did it limit overall participation in life activities. Although the significance of memory decline in the current study was not determined quantitatively, memory decline is consistent with the early deterioration characteristic of mild cognitive impairment and preclinical Alzheimer's disease and confirms the need to monitor individuals with objective memory decline, even when these individuals fall within normal limits for a given neuropsychological task.

A new Brief computerized cognitive screening battery (CompCogs) for early diagnosis of Alzheimer's disease

Screening tests for early diagnosis of dementia are of great clinical relevance. The ideal test set must be brief and reliable, and should probe cognitive components impaired in Alzheimer’s disease (AD).

Depression, antidepressants, and plasma amyloid beta (Beta) peptides in those elderly who do not have cardiovascular disease

BACKGROUND

Low plasma amyloid-beta peptide 42 (Abeta42) is associated with depressive symptoms independently of cardiovascular disease (CVD) in the elderly. It is critical to investigate whether antidepressants modify this relationship.

METHODS

We evaluated 324 elders without CVD in a cross-sectional study. Depression was evaluated with the Center for Epidemiological Studies Depression (CES-D) scale. Antidepressants were documented. Plasma Abeta40 and Abeta42 were measured.

RESULTS

In the absence of CVD, those with depression had lower plasma Abeta42 (median: 13.7 vs. 18.8 pg/mL, p = .003) than those without. Depressed subjects on antidepressant treatment had a lower concentration of plasma Abeta40 (median: 97.8 vs. 133.5 pg/mL, p = .008), but not Abeta42, than those without the treatment. Multivariate logistic regression showed that antidepressant use did not influence the relationship between depression and low plasma Abeta42 (odds ratio = .55; 95% CI = .33, .90; p = .02) after adjusting for confounders, but its use interacted with plasma Abeta40 in the model.

CONCLUSIONS

Lower concentration of plasma Abeta42 is associated with depression in the absence of CVD that is not related to the antidepressant use by those subjects. Prospective studies are needed to determine whether depression associated with low plasma Abeta42 predicts the onset of Alzheimer's disease.

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.

Depression is associated with low plasma Abeta42 independently of cardiovascular disease in the homebound elderly

BACKGROUND

Depression often precedes the onset of Alzheimer's disease (AD) before the appearance of cognitive symptoms. Plasma Amyloid-beta peptide 42 (Abeta42) declines before and soon after the onset of AD, yet the relationship between plasma Abeta42 and depression is unclear.

METHODS

We used 515 homebound elders aged 60 and older in a population-based, cross-sectional study to investigate associations between plasma Abeta levels and depression with and without cardiovascular co-morbidities. Depression was evaluated by using the Center for Epidemiological Studies Depression (CES-D) scale. Plasma Abeta40 and Abeta42 were measured.

RESULTS

The elderly with depression had lower plasma Abeta42 (median: 15.3 vs. 18.9, p = 0.008) than those without depression. The CES-D score was inversely associated with plasma Abeta42 (p = 0.001) in subjects with no cardiovascular disease (CVD); however, in the presence of CVD, this association did not exist. Low plasma Abeta42 (OR = 0.41, p = 0.007) and the presence of CVD (OR = 1.84, p = 0.005) were independently associated with depression after adjusting for the confounders of age, stroke and apolipoprotein E4.

CONCLUSIONS

Depressive symptoms are associated with low plasma Abeta42 independently of CVD. Prospective studies are needed to determine whether depression associated with low plasma Abeta42 is a separate depression subtype that could predict the onset of AD.

Hormones and dementia - a comparative study of hormonal impairment in post-menopausal women, with and without dementia

CONTEXT

Women seem to be more vulnerable to dementia, particularly Alzheimer's disease (AD), than men. There is controversy among studies correlating estrogen deficit to cognitive impairment. Because of the sudden drop of estrogens in menopause, this hormonal deficit could represent one of the risk factors for the larger incidence and prevalence of AD in post-menopausal women.

RATIONALE

We therefore wanted to find out if post-menopausal women with dementia, or even in a prior stage, mild cognitive impairment (MCI), would have a more significant deficit of estrogens than post-menopausal women without dementia, or any other type of cognitive problem.

OBJECTIVES

The aim of this study was to detect possible differences of the sex hormone levels among post-menopausal women, simultaneously affected by MCI or dementia, in comparison with a control group without cognitive impairment.

DESIGN, SETTING, AND PARTICIPANTS

A small, multicenter, prospective study was performed on 82 post-menopausal women (41 cases, 41 controls), aged 45-81 years, to investigate their sex hormone balance. The diagnosis of dementia was made according to ICD 9 or 10 and DSM III-R or IV appropriate to the time interval. The diagnosis of probable AD followed the NINCDS-ADRDA criteria. MCI met the Paquid-study criteria. Blood was analyzed in qualified centers for LH, FSH, and 17-beta-estradiol. All women went through a thorough psychiatric examination and those with a suspected hormonal impairment were examined by a gynecologist.

RESULTS

15 cases (36.6%) had impaired hormonal function, compared with 8 controls (19.5%). Of the 15 cases with hormonal impairment, 9 had MCI.

CONCLUSIONS

These preliminary data stress a considerable difference between the sex hormone status of these two populations, showing a tendency towards a more accentuated estrogen deficit linked to cognitive deficit. Enlarging the sample and following the evolution could bring more interesting data.

Neuropsychological markers of progression from mild cognitive impairment to Alzheimer's disease

To find early clinical markers that may predict a likely progression to Alzheimer's disease (AD), the authors performed neuropsychological tests on 82 mild cognitive impairment (MCI) subjects. After 3 years, 38 patients developed AD while 44 retained the diagnosis of MCI. The cognitive differences between the groups were studied. Patients who developed AD showed significantly lower values than did MCI subjects in some neuropsychological scores (P = .02-.001), with sensitivities and specificities higher than 84% and 64%, respectively, for detecting early-onset AD, with a 7.9-fold increased risk of converting to AD (P < .001). Regarding the logistic regression model, the CAMCOG Memory and Perception cognitive screening items were the optimum independent tools to classify the patients who will progress to AD, showing a relative risk of progression of 10.5 (P = .002), 5.5 (P = .008), and 3.9 times (P = .05), respectively, with a sensibility of of 92.1% and a specificity 72.7%.

Mild memory impairment in healthy older adults is distinct from normal aging

Mild memory impairment was detected in 28% of a sample of healthy community-dwelling older adults using the delayed recall trial of a word list learning task. Statistical analysis revealed that individuals with memory impairment also demonstrated relative deficits on other measures of memory, and tests of executive function, processing speed and global cognition, as measured by the CERAD and CogState batteries and CANTAB paired associate learning task. These relative deficits cannot be explained by age-related changes, education, intelligence, mood, health-related factors, or the individuals' ApoEepsilon4 status. Memory-impaired individuals (n = 30) did not recognize the extent of their memory and cognitive difficulties beyond the general complaints expressed by normal elderly (n = 77) within the study and their apparent difficulties did not appear to impact on their participation in life activities. These findings suggest it is unlikely that the memory and cognitive difficulties demonstrated by individuals with mild memory impairment reflect normal aging. Rather it is possible that such impairment may signal early neurodegenerative processes worthy of further investigation.

Association between Physical and Cognitive Function in Healthy Elderly: The Health, Aging and Body Composition Study

Performance measures of physical function (gait speed, chair stands, standing balance) and cognitive function [Teng-modified Mini-Mental Status Exam (3MS) and digit symbol substitution test (DSST)] were assessed at baseline in 3,075 participants in the Health, Aging and Body Composition Study. Each physical function measure was examined for the strength and magnitude of association with cognitive function. All physical function measures were associated with both the 3MS and DSST scores (p < 0.001), and in multivariate analysis each relationship was independent of demographic characteristics, weight, physical activity and comorbid health conditions of participants. The association of motor performance was consistently greater for the DSST than the 3MS and, among the motor tests, gait speed retained a significant association with both cognitive measures independent of demographic, weight, physical activity and comorbid health conditions. In this large cohort of high-functioning older adults, the correlation between physical and cognitive function was not entirely explained by demographics. Longitudinal studies are needed to determine the direction of causality in this relationship.

Looking Backward to Move Forward: Early Detection of Neurodegenerative Disorders

Early detection of neurodegenerative disorders would provide clues to the underlying pathobiology of these diseases and would enable more effective diagnosis and treatment of patients. Recent advances in molecular neuroscience have begun to provide the tools to detect diseases like Alzheimer's disease, Parkinson's disease, and others early in their course and potentially even before the development of clinical manifestations of disease. These genetic, imaging, clinical, and biochemical tools are being validated in a number of studies. Early detection of these slowly progressive diseases offers the promise of presymptomatic diagnosis and, ultimately, of disease-modifying medications for use early in disease and during the presymptomatic period.

What is mild cognitive impairment? Variations in definitions and evolution of nondemented persons with cognitive impairment

Numerous studies have endeavoured to explore the nature of cognitive impairment in nondemented elderly persons. Comparison of this literature is hampered by huge variations in criteria and methodology. Despite these limitations, there are repeated reports that nondemented persons with cognitive impairment have a higher chance of progressing to dementia. Evidence also indicates higher mortality in cognitively impaired persons but there is also a chance of improvement in cognition over time. The current paper provides an overview of the various concepts and criteria proposed for cognitive impairment in nondemented persons, discusses some of the problems with current research in this field, and presents some of the findings concerning the evolution of cognitive impairment in relation to dementia, mortality and cognitive improvement.

Detection of Alzheimer's disease and dementia in the preclinical phase: population based cohort study

OBJECTIVES

To evaluate a simple three step procedure to identify people in the general population who are in the preclinical phase of Alzheimer's disease and dementia.

DESIGN

Three year population based cohort study.

SETTING

Kungsholmen cohort, Stockholm, Sweden.

PARTICIPANTS

1435 people aged 75-95 years without dementia.

ASSESSMENTS

Single question asking about memory complaints, assessment by mini-mental state examination, and neuropsychological testing.

MAIN OUTCOME MEASURE

Alzheimer's disease and dementia at three year follow up.

RESULTS

None of the three instruments was sufficiently predictive of Alzheimer's disease and dementia when administered separately. After participants had been screened for memory complaints and global cognitive impairment, specific tests of word recall and verbal fluency had positive predictive values for dementia of 85-100% (95% confidence intervals range from 62% to 100%). However, only 18% of future dementia cases were identified in the preclinical phase by this three step procedure. Memory complaints were the most sensitive indicator of Alzheimer's disease and dementia in the whole population, but only half the future dementia cases reported memory problems three years before diagnosis.

CONCLUSION

This three step procedure, which simulates what might occur in clinical practice, has a high positive predictive value for dementia, although only a small number of future cases can be identified.

Mild cognitive impairment--a review of prevalence, incidence and outcome according to current approaches

OBJECTIVE

Mild cognitive impairment is associated with an increased risk of developing dementia. However, agreement needs to be reached on clearly specified diagnostic criteria for mild cognitive impairment. The present paper critically reviews the different constructs of mild cognitive impairment on the basis of the available empirical evidence.

METHOD

All published papers on mild cognitive impairment during the last 15 years on Medline and other databases were reviewed.

RESULTS

Age-specific prevalence and incidence rates according to the different constructs as well as the prognostic significance of the different constructs concerning the development of dementia are reported. Furthermore, a brief summary of recent research on possible risk factors for a negative course of mild cognitive impairment is provided.

CONCLUSION

As there is no construct to date that pools all efforts of defining mild cognitive impairment, the review provides suggestions for an agreement on constructive terminology and research practice.

Impaired cerebral glucose metabolism and cognitive functioning predict deterioration in mild cognitive impairment

The objective of this study was to assess whether reduced glucose metabolism (rCMRGlu) and cognitive functioning could predict development of Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI). Twenty MCI patients underwent baseline and follow-up investigations of rCMRGlu, as measured by PET, and cognitive function measured by neuropsychological test assessments. Subjects were clinically followed up with an average interval of 36.5 months. Two groups were obtained after the second clinical assessment. Nine patients were diagnosed as AD and classified as progressive MCI (P-MCI), whereas 11 patients remained clinically stable and were classified as stable MCI (S-MCI). There were no differences in demographic variables or baseline MMSE between the two subgroups. Logistic regression indicated the two variables that most effectively predicted future development of AD were rCMRGlu from the left temporoparietal area and performance on the block design. These combined measures gave an optimal 90% correct classification rate, whereas only rCMRGlu or neuropsychology alone gave 75% and 65% correct classification, respectively. Measures of temporoparietal cerebral metabolism and visuospatial function may aid in predicting the evolution to AD for patients with MCI.