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Biomedical subjects

C Jonker

Publications and source records attributed to C Jonker.

At least 55 records · Page 3Linked to original sources
PubMed1999

Education and incident Alzheimer's disease: a biased association due to selective attrition and use of a two-step diagnostic procedure?

BACKGROUND: It is still not clear whether a low level of education increases the risk of developing Alzheimer's disease (AD). Two common problems in cohort studies involving an elderly population and a two-step diagnostic procedure are the loss to follow-up without data on the presence of AD, and the fact that, in general, people with higher levels of education perform better on traditional cognitive tests, such as the Mini-Mental State Examination (MMSE). Both phenomena may lead to misclassification, resulting in a biased association between level of education and AD. This study investigated to what extent these selection mechanisms may influence this association. METHODS: In the community-based Amsterdam Study of the Elderly (AMSTEL) a cohort at risk for AD was selected of 3778 people aged 65-84 years. Level of education was expressed in two categories: low (primary education or less) versus high (partial secondary education to completed university education). At follow-up, a subsample of elderly people was selected for further diagnostic evaluation, using a memory test in addition to the MMSE. Clinical diagnoses of AD were made according to DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) criteria. To examine the extent to which loss to follow-up may have affected the results, a sensitivity analysis was performed comparing two extreme possibilities. Furthermore, to examine to what extent use of the MMSE only may have affected the results, the observed odds ratio (OR) was compared with the OR based on only those AD patients who were selected for diagnostics with the MMSE alone. RESULTS: After an average of 3.2 years, 77 people had developed AD. Multivariate logistic regression analyses indicated that a low level of education was associated with incident AD (OR adjusted for age and sex 2.09; 95% CI: 1.29-3.38). The results of the sensitivity analysis still indicated that a low level of education was associated with incident AD. Screening with only the MMSE led to a higher OR than the one observed. CONCLUSION: Selective attrition and use of cognitive screening tests that are associated with educational level may influence the strength of the association between a low level of education and incident AD; however, it appears that these influences cannot completely explain this association.

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PubMed1999

Nonlinear EEG analysis in early Alzheimer's disease.

Nonlinear EEG analysis attempts to characterize the dynamics of neural networks in the brain. Abnormalities in nonlinear EEG measures have been found repeatedly in Alzheimer's disease (AD). The present study was undertaken to investigate whether these abnormalities could already be found in the early stage of AD. In a representative sample of 49 community-dwelling elderly, Alzheimer's disease was diagnosed in 7 subjects. Correlation dimension (D2) and nonlinear prediction were measured at 16 electrodes and in two different activational states. Also, 10 surrogate data sets were generated for each EEG epoch in order to investigate the presence of nonlinear dynamics. Differences between nonlinear statistics derived from original and from surrogate data sets were expressed as Z-scores. We found lower D2 and higher predictability in the demented subjects compared to the normal subjects. The results obtained with the Z-scores pointed to changed nonlinear dynamics in frontal and temporal areas in demented subjects. However, the major differences between demented and healthy subjects are not due to nonlinearity. From this it appears that linear dynamics change first in the course of AD, followed by changes in nonlinear dynamics.

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PubMed1999

Association between memory complaints and incident Alzheimer's disease in elderly people with normal baseline cognition.

OBJECTIVE: Results of previous studies suggest that memory complaints may predict cognitive decline and dementia among elderly people in whom cognitive impairment is already apparent. However, cognitive decline is often a gradual process, and elderly people may notice that their memory deteriorates before mental status tests are able to detect any change in cognitive functioning. Therefore, the authors hypothesized that memory complaints would predict incident Alzheimer's disease in elderly subjects with no signs of cognitive impairment. METHOD: In the community-based Amsterdam Study of the Elderly, a sample of 3,778 nondemented persons, 65 to 84 years old, was selected and divided into two cognitive categories: normal (Mini-Mental State scores of 26-30) and borderline and impaired (Mini-Mental State scores less than 26). At baseline, the presence or absence of memory complaints was assessed. At follow-up, incident cases of Alzheimer's disease were diagnosed in a two-step procedure. RESULTS: After an average of 3.2 years, 2,169 persons were reevaluated, of whom 77 had incident Alzheimer's disease. Multivariate logistic regression analyses showed that memory complaints were associated with incident Alzheimer's disease in subjects with normal baseline cognition but not in subjects with impaired baseline cognition. CONCLUSIONS: The findings of this study suggest that memory complaints are a relatively strong predictor of incident Alzheimer's disease in older persons in whom cognitive impairment is not yet apparent. Furthermore, they suggest that older persons may be aware of a decline in cognition at a time when mental status tests are still unable to detect a decline from premorbid functioning.

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PubMed1999

Development of the EURO-D scale--a European, Union initiative to compare symptoms of depression in 14 European centres.

BACKGROUND: In an 11-country European collaboration, 14 population-based surveys included 21,724 subjects aged > or = 65 years. Most participating centres used the Geriatric Mental State (GMS), but other measures were also used. AIMS: To derive from these instruments a common depression symptoms scale, the EURO-D, to allow comparison of risk factor profiles between centres. METHOD: Common items were identified from the instruments. Algorithms for fitting items to GMS were derived by observation of item correspondence or expert opinion. The resulting 12-item scale was checked for internal consistency, criterion validity and uniformity of factor-analytic profile. RESULTS: The EURO-D is internally consistent, capturing the essence of its parent instrument. A two-factor solution seemed appropriate: depression, tearfulness and wishing to die loaded on the first factor (affective suffering), and loss of interest, poor concentration and lack of enjoyment on the second (motivation). CONCLUSIONS: The EURO-D scale should permit valid comparison of risk-factor associations between centres, even if between-centre variation remains difficult to attribute.

Age Distribution↗
PubMed1999

[Normal values for a short form of the Raven Colored Progressive Matrices].

Psychometric data are presented for the Raven Coloured Progressive Matrices (RCPM), shortened to series A and B. The data were derived from a sample of 2791 persons aged 55 to 85 years. Six 5-year age strata were equally represented, as well as both sexes. The distribution of educational attainment was representative for the elderly population. Norms were stratified for age and education; gender differences were too small to necessitate separate norms. Analysis of reliability according to Mokken's IRT-model indicated modest scalability, but high internal consistency. A loss of 2 to 4 points at retest (depending on personal characteristics) is interpretable as a loss of capacity. Ample attention is paid to qualitative aspects of test performance, but it is concluded that error analysis is mainly useful to def1p4 positional preferences.

Age Factors↗
PubMed1998

Association between apolipoprotein E epsilon4 and the rate of cognitive decline in community-dwelling elderly individuals with and without dementia.

OBJECTIVE: To determine whether the apolipoprotein E epsilon4 allele (apoE epsilon4) is associated with cognitive decline in individuals with and without dementia, we conducted a 4-year longitudinal study of subjects with a range of cognitive function. SETTING: At baseline, respondents (n=511) were randomly selected according to age and Mini-Mental State Examination score from a community-based study of dementia among noninstitutionalized persons aged 65 to 84 years. Respondents were examined at baseline and followed up in 3 annual visits. At baseline, subjects were classified as having normal cognitive function, minimal dementia, or dementia, according to criteria from the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX) and the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Of the 511 respondents at baseline, 405 who were examined at least 2 times are included in this analysis. MAIN OUTCOME MEASURES: Cognitive decline was determined by a slope estimating yearly change in score on the neuropsychological test, the CAMCOG (the cognitive section of the CAMDEX), and its sub-scales of memory and nonmemory functions. RESULTS: Among the subjects who had normal cognitive function at baseline, apoE epsilon4 carriers showed a significantly greater decline (P<.001) in score on the CAMCOG compared with noncarriers. Differences in decline on the memory and nonmemory subtests were also significant (P<.001). Rates of cognitive decline were not related to apoE epsilon4 status in the groups with minimal dementia and dementia. CONCLUSIONS: In our community-based sample, apoE epsilon4 was associated with the rate of cognitive decline prior to the clinically symptomatic phase of dementia. Knowing the apoE epsilon4 status of those already symptomatic for dementia may not improve knowledge about a patient's prognosis.

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PubMed1998

Apolipoprotein E phenotype is not related to late-life depression in a population-based sample.

Apolipoprotein E (ApoE) allele frequencies were examined in a population-based sample (n = 475: age range 65-84 years: Amsterdam Study of the Elderly). The relation of ApoE epsilon 4 with dementia and with various types of late-life depression was studied. Depression was measured with the Geriatric Mental State schedule. Dementia was diagnosed by DSM-III-R criteria. It was expected that ApoE epsilon 4 allele frequencies would be elevated not only in Alzheimer's disease and dementia in general, but also in first episode, late-life depression accompanied by subtle cognitive impairment (possibly organic depression). However, the results indicated that epsilon 4 allele frequency is related to (family history of) dementia and cognitive impairment, but not to possibly organic depression. The main predictor of late-life depression is an episode of psychiatric problems before the age of 65 years.

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PubMed1998

Psychological distress of caregivers: the mediator effect of caregiving appraisal.

This study concerns the role of caregiving appraisal, whether it explains why stressors in the caregiving situation affect caregivers' psychological distress. This putative mediator effect of caregiving appraisal is separately tested for spouse and non-spouse caregivers of demented elderly persons. Caregiving appraisal is operationalized by a measure of pressure from informal care as perceived by the caregiver. For spouse caregivers, perceived pressure explained the association between their caregiving tasks and psychological distress. However, the strong association found between behavioral problems and psychological distress was not explained by perceived pressure in spouse caregivers. Furthermore, results showed clear mediator effects of perceived pressure for associations between stressors (both behavioral problems of the demented elder and caregiving tasks) and non-spouse caregivers' psychological distress. Thus, it is inadequate to focus interventions merely on stressors in the caregiving situation, for non-spouse caregivers in particular. A reduction of perceived pressure from informal care is also needed.

Adaptation, Psychological↗
PubMed1998

Reading ability as an estimator of premorbid intelligence: does it remain stable in emergent dementia?

The 6-year stability of reading performance was investigated in subjects who were normal at baseline but suspect for dementia at follow-up (MMSE score < or = 23; n = 197), and in a cognitively intact control group (n = 117). The Dutch version of the National Adult Reading Test (DART) was used. The DART-based estimate of IQ appeared to be very stable in healthy elderly. In the "suspect" group, the decline after 6 years was about 3 IQ-points in subjects who were still not demented, minimally demented, or mildly demented. Reliability remained satisfactory in these subgroups. In cases with moderate and severe dementia, the decline was considerable (> or = 15 IQ points). The decline of DART IQ was related to deterioration of semantic memory as reflected in verbal abstraction and category fluency. It is concluded that the DART remains a valid estimator of premorbid verbal intelligence in mild and questionable dementia. A formula is presented which can correct the underestimation on the basis of the MMSE score.

Adult↗
PubMed1998

Elder abuse in the community: prevalence and consequences.

OBJECTIVES: (1) To assess the prevalence and the consequences of chronic verbal aggression, physical aggression, financial mistreatment, and neglect in a community-based sample; (2) to investigate the circumstances that led to the abuse and the ways in which the victims handled the problem. DESIGN: Prevalence was assessed in a population-based sample of 1797 older people living independently in Amsterdam, the Netherlands. In a follow-up study 1 year later, the victims were questioned again about the background and consequences of the abuse. RESULTS: The 1-year prevalence of elder abuse was 5.6%. The prevalence of the various types of elder abuse was: verbal aggression 3.2%, physical aggression 1.2%, financial mistreatment 1.4%, and neglect 0.2%. Most victims reported emotional reactions immediately after the abuse. Seven of 36 victims experienced physical or financial damage as a consequence of the abuse. More than 70% of the victims were able to stop the abuse, either by themselves or with the help of others. CONCLUSION: The rate of occurrence and the consequences of elder abuse in the Netherlands was established. Elder abuse is more widely spread if not only close relatives or people with whom the older person lives are considered as possible perpetrators but other familiar and trusted people are considered as well. Intervention should be focused on the roughly 40% of victims who were not able to stop the abuse.

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PubMed1997

[The Stimulation Program Health Research. X. Evaluation of the program section 'Psychogeriatrics'].

In the programme section 'Psychogeriatrics' of the SGO Health Research Promotion Programme a longitudinal study was carried out in Amsterdam from 1989 until 1994, concerning the course of mild cognitive decline in elderly people (the AMSTEL project). The scientific aims were the development of diagnostical instruments for the early diagnosis of dementia, the development of criteria which predict the course of mild cognitive impairment and the expansion of knowledge on the relationship between somatic and psychiatric pathology and dementia. The programme also had aims regarding medical education and patient care. The results include the following: in order to diagnose dementia in general practice questions regarding orientation and short-term memory are helpful. Risk factors for cognitive deterioration in elderly people include hippocampal atrophy on the MRI scan, a low level of education and subjective complaints regarding memory. Subjective complaints regarding memory are not primarily caused by a depressive mood, as is often thought, but are important as correct self-observations of cognitive deterioration, and go with an increased risk of developing dementia. Besides the AMSTEL project a feasibility study was carried out concerning a psychogeriatric case register in Amsterdam.

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PubMed1997

Norms for an abbreviated Raven's Coloured Progressive Matrices in an older sample.

Percentile age norms for ages 55 to 85 using overlapping intervals at specified age midpoints are presented for the sum scores of sections A and B of Raven's Coloured Progressive Matrices (RCPM). The representative age and gender stratified sample (N = 2,815) used is derived from the Longitudinal Aging Study Amsterdam (the Netherlands). As RCPM scores appear to be strongly associated with education, percentile norms for three educational levels are presented: low (0-9 years), middle (10-15 years) and high (16 years and more).

Aged↗
PubMed1997

Limitations of the Mini-Mental State Examination in diagnosing dementia in general practice.

The aim of the study was to investigate the value of the Mini-Mental State Examination (MMSE) for use by general practitioners (GPs) in a group of elderly patients in whom the GPs are considering a dementia diagnosis. The study population consisted of 533 elderly patients (aged 65 and older) judged by 36 GPs as suffering from 'minimal to severe' dementia. Cross-sectional data were used to determine the criterion validity of separate items, a set of items and the total MMSE. The GMS/AGECAT diagnosis was used as an external criterion. MMSE items were analysed and two items testing general knowledge were added. The most effective set of items was determined using a stepwise logistic regression analysis. Adjusted for age, sex and education, the differentiating ability of the set of items was compared to that of the total MMSE score. The total MMSE score was divided into three categories (cutoffs 21/22 and 26/27) and into two categories (cutoff 23/24). In total, 114 patients (21%) were diagnosed as having an 'organic syndrome' by the GMS/AGECAT. The differentiating ability of separate items was poor. The following combination of items had the best predictive ability: items concerning the date, the day of the week, the patient's address and the current prime minister. This set of items was just as adequate in differentiating dementia from non-dementia as the total MMSE score (sensitivity 64.9% and 64.8% respectively, specificity 96.4% and 93.3%). The value of the MMSE in diagnosing dementia in general practice is limited. The score on cognitive test items can be one aspect of the individual's overall clinical picture, on which the diagnosis should be based.

Aged↗
PubMed1997

Low education is a genuine risk factor for accelerated memory decline and dementia.

A relatively high prevalence and incidence of dementia have been found in population strata with low levels of education in comparison to population strata with high levels of education. However, doubt remains whether this may be an artifact of education bias in the screening tests used. To investigate this matter, we analyzed results of two Dutch population surveys in which unbiased measures of memory decline were used. In the Longitudinal Aging Study Amsterdam (n = 1774) the percentage of words retained in a verbal learning test was found to be disproportionately low in the oldest age cohort (80-85 years) with less than 11 years of education. The Amsterdam Study of the Elderly (n = 4051) found a "dose-response" relationship between education and dementia prevalence. Cross-sectional and longitudinal results showed that, in less educated people, memory decline is faster and sets in at an earlier age. These findings indicate that the relationship between dementia and education is not just an artifact of case detection methods.

Aged↗
PubMed1997

The diagnostic value of magnetic resonance imaging and technetium 99m-HMPAO single-photon-emission computed tomography for the diagnosis of Alzheimer disease in a community-dwelling elderly population.

The objective of this study was to assess the diagnostic value for Alzheimer disease (AD) of single-photon-emission computed tomography (SPECT) and magnetic resonance imaging (MRI), separately and in combination. The study was part of a two-stage population-based study of mental functioning among noninstitutionalized 65-to 85-year-olds living in Amsterdam, The Netherlands. Participants (n = 51) were randomly selected within strata of cognitive function to obtain a sample of AD patients (n = 10) and clinically normal subjects (n = 41), of whom 22 displayed some cognitive impairment and fulfilled criteria for "minimal dementia" according to the Cambridge Examination for Mental Disorders of the Elderly. Coronal T1-weighted MRI was used to visualize the medial temporal lobe. Medial temporal lobe atrophy (MTA) was assessed qualitatively on a 0-4 scale. Regional cerebral blood flow on SPECT was assessed with the use of technetium 99m-HMPAO in three manually drawn regions of interest (frontal, parietal, and temporoparietal). Ratios were calculated by using the cerebellum as the reference area. MTA differed significantly between AD patients and clinically normal subjects (p = 0.0009), with sensitivity for AD of 70% and a specificity of 76%. None of the three SPECT ratios differed between normal and AD subjects. The temporoparietal/cerebellar ratio had a sensitivity of 30% and a specificity of 71% as a cutoff of 0.76. When both tests were positive the combined sensitivity was low (20%), but the false-positive rate was also very low (5%). A negative result on MRI or any SPECT ratio yielded a high specificity (93%-98%) but also a high false-negative rate (60-80%). Adding SPECT to MRI seems useful only if a diagnosis of AD is suspected clinically and confirmation is needed. When the clinical probability that AD is absent is high, normal results on either MRI or SPECT may confirm this notion. Given the fact that structural imaging should be performed in a clinical workup for dementia, using MRI only would be the most cost-effective approach.

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PubMed1997

Cognitive and emotional predictors of disablement in older adults.

This study focused on the association between aspects of emotional and cognitive functioning and two stages of the disablement process model, functional limitations, and instrumental activities of daily living (IADL) disability. The age- and sex-stratified sample aged 55 to 89 years consisted of 100 inhabitants of a small Dutch town who scored 24 or higher on the Mini Mental State Examination (MMSE). Controlling for background factors (health problems, age, education, and gender), depressive symptoms and fluid intelligence were independently associated with functional limitations. Of the cognitive functions, only everyday memory was independently associated with IADL disability. Emotional functioning was not independently associated with IADL disability. These findings expand on the disablement process model and demonstrate the importance of emotional functioning, fluid intelligence, and everyday memory for the disablement process.

Activities of Daily Living↗
PubMed1997

Subjective memory complaints in the elderly: depressive symptoms and future dementia.

BACKGROUND: Population studies indicate that subjective memory complaints by elderly people are correlated with cognitive performance. These complaints have some predictive power regarding the development of dementia. The present study attempted to replicate this finding, and investigated which variables determine subjective memory complaints. METHOD: Participants in the Amsterdam Study of the Elderly (n = 2114; 65-84 years of age), who were not demented and had a normal MMSE score (> 23) at baseline, were re-examined after four years. Subjective complaints were measured using a previously developed scale. Dementia and depression were measured using the Geriatric Mental State Schedule (GMS). Premorbid intelligence was measured by the Dutch Adult Reading Test (DART). RESULTS: Memory complaints at baseline contributed a small but significant amount of diagnostic information with respect to the prediction of future dementia. Depressive symptoms at baseline had no predictive value when these memory complaints were accounted for. Subjective memory complaints were associated with depression, baseline MMSE score, and premorbid intelligence. CONCLUSIONS: Subjective memory complaints are not just secondary to depression, but in part reflect realistic self-observations of cognitive decline.

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