The MRC Multicentre Study of Cognitive Function and Ageing: a EURODEM incidence study in progress

Community mental health nursing and early intervention in dementia: developing practice through a single case history

People Nursing in association with Journal of Clinical Nursing 13, 6b, 57-67 Community mental health nursing and early intervention in dementia: developing practice through a single case history This paper reports on a single case history taken from the 'Dementia Action Research and Education' project, a 15-month primary care intervention study that was undertaken in North Wales in the early part of 2000. The study sought to address the meaning, context and diversity of early intervention in dementia care and employed a community mental health nurse and a psychiatric social worker to undertake early and psychosocial interventions with older people with dementia (aged 75 years and over) and their families. The workers tape-recorded, documented and analysed their interventions with 27 older people with dementia and their families over the 15-month duration of the study. Clinical supervision was also undertaken during the intervention phase. One case history is presented in this paper to illustrate the work of the community mental health nurse and to identify areas of practice development. Greater role transparency, collaborative working and improvement in educational preparation for practice are called for.

Attrition and bias in the MRC cognitive function and ageing study: an epidemiological investigation

BACKGROUND

Any hypothesis in longitudinal studies may be affected by attrition and poor response rates. The MRC Cognitive Function and Ageing study (MRC CFAS) is a population based longitudinal study in five centres with identical methodology in England and Wales each recruiting approximately 2,500 individuals. This paper aims to identify potential biases in the two-year follow-up interviews.

METHODS

Initial non-response: Those not in the baseline interviews were compared in terms of mortality to those who were in the baseline interviews at the time of the second wave interviews (1993-1996). Longitudinal attrition: Logistic regression analysis was used to examine baseline differences between individuals who took part in the two-year longitudinal wave compared with those who did not.

RESULTS

Initial non-response: Individuals who moved away after sampling but before baseline interview were 1.8 times more likely to die by two years (95% Confidence interval(CI) 1.3-2.4) compared to respondents, after adjusting for age. The refusers had a slightly higher, but similar mortality pattern to responders (Odds ratio 1.2, 95%CI 1.1-1.4). Longitudinal attrition: Predictors for drop out due to death were being older, male, having impaired activities of daily living, poor self-perceived health, poor cognitive ability and smoking. Similarly individuals who refused were more likely to have poor cognitive ability, but had less years of full-time education and were more often living in their own home though less likely to be living alone. There was a higher refusal rate in the rural centres. Individuals who moved away or were uncontactable were more likely to be single, smokers, demented or depressed and were less likely to have moved if in warden-controlled accommodation at baseline.

CONCLUSIONS

Longitudinal estimation of factors mentioned above could be biased, particularly cognitive ability and estimates of movements from own home to residential homes. However, these differences could also affect other investigations, particularly the estimates of incidence and longitudinal effects of health and psychiatric diseases, where the factors shown here to be associated with attrition are risk factors for the diseases. All longitudinal studies should investigate attrition and this may help with aspects of design and with the analysis of specific hypotheses.

Performance and normative values of a concise neuropsychological test (CAMCOG) in an elderly population sample

BACKGROUND

CAMCOG is a widely used brief neuropsychological test. To date no normative values are available for English speaking individuals representative of the general population.

OBJECTIVES

The aims of the study were to describe the population distribution of performance on CAMCOG, and to provide normative data derived from a representative population sample.

METHODS

CAMCOG was administered at the assessment stage of the MRC Cognitive Function and Ageing Study. MRC CFAS is a multi-centre population-based study in England and Wales in respondents aged 65 years and older. Initial screening provided provisional identification of cognitive impairment. The subsequent assessment interview provided an algorithmic diagnosis of dementia, or other disorders, in a 20% sub-sample.

RESULTS

There were large differences between demented and non-demented groups on the CAMCOG total score and on all CAMCOG subscales. Charts of normative values for CAMCOG are presented by age group, sex and education for the non-demented population (n = 1 914, representing 11 008 individuals screened).

CONCLUSIONS

Population-derived normative data are valuable for comparing an individual's score to the score which would be expected of the general population, given the individual's specific demographic characteristics.

The experience of caring for older people with dementia in a rural area: using services

This paper reports findings from the carer component of the Gwynedd Dementia Study. It is based on carer interviews, using quantitative and qualitative data. It confirms earlier findings that carers for people with dementia are typically female and older than other carers, although it notes that caring husbands are amongst the oldest carers. The problems that are most common are those that cause psychological stress to carers. Carers were found to receive both help and appreciation from their families and to perceive neighbours to be helpful if needed. In Gwynedd, as elsewhere, levels of formal service inputs are low, but most of the carers appeared to receive the services they needed. Problems are primarily associated with crisis support and long-term care is accepted reluctantly. It is suggested that community care dementia specialists could play a supporting role for carers.

A review of ordinal regression models applied on health-related quality of life assessments

There has been increasing emphasis in medical research on the design and analysis of quality of life scales. Many quality of life scales are ordinal and statistical methods such as ordinal regression models have been reviewed on a number of occasions. However, when such models are applied, the way the data have been generated is often overlooked. In this paper we illustrate the use of ordinal regression models, in particular the proportional odds model, the partial proportional odds model and the stereotype model in the MRC Cognitive Function and Ageing Study (MRC CFAS). The partial proportional odds and the stereotype models are often under-utilized, perhaps due to the lack of available software. However, in this paper, analysis based on these models has been carried out using the popular statistical software package SAS and macros devised in SAS. Furthermore, bootstrapping techniques have been applied to obtain valid estimates of the standard errors of the parameters in the stereotype model. Strikingly different results were obtained using the different ordinal regression models. We conclude that the way the data have been generated is particularly important for the analysis of quality of life assessments. Different methods of generating scores yield data with different properties. It is now possible to fit a variety of ordinal regression models and so select the appropriate one that correctly models the data.

Cognitive function in the Caerphilly study: associations with age social class, education and mood

Baseline cognitive function was established for a study of pre-symptomatic cognitive decline in 1870 men from the general population aged 55-69 years as part of the third examination of the Caerphilly Study. Cognitive assessment included the AH4, a four choice serial reaction time task, a modified CAMCOG, MMSE, NART and various memory tests. Distributions and relationships with age, social class, education and mood at time of testing are presented for a younger population than has previously been available. Multiple linear regression showed cognitive function to be independently associated with all four factors. The age effect was equivalent to one half of a standard deviation (SD) in CRT and AH4 scores. Only the NART score was not associated with age, supporting the use of NART score as an estimate of pre-morbid IQ. The largest age adjusted differences between men with low and normal mood were for the AH4 (3 points, t = 5.6, p < 0.0001) and the CAMCOG (2 points, t = 5.8, p < 0.0001). The smallest age adjusted effect of mood was for the CRT (33 ms, t = 2.14, p = 0.32) and the MMSE (0.4 points, t = 2.97, p = 0.003). Age, mood and education adjusted social class effects were very large ranging between around 0.5 SD for the CRT, and 1.0 SD for the AH4 and NART, respectively. For educational status age, mood and social class adjusted differences were also substantial with tests for trend showing the largest differences for the NART (t = 12, p < 0.0001) and modified CAMCOG (t = 10.6, p < 0.0001) with the smallest differences for the CRT (t = 2.73, p = 0.006).

Do experienced diagnosticians agree about the diagnosis of dementia from survey data? The effects of informants' reports and interviewers' vignettes

Dementia in community settings is often diagnosed by computerized algorithms. This study examines the extent to which independent diagnosticians agreed among themselves in diagnosing dementia, severity and type when presented with data obtained during a population-based incidence study of cognitive decline and dementia. Secondly, it examines how judgements, based initially on respondents' self-reports and cognitive performance, were affected first by informants' reports and then by short case-vignettes written by trained lay interviewers. Thirdly, it compares diagnosticians' diagnosis of dementia with the algorithmic diagnosis (AGECAT). The items presented were selected from two screening interviews at wave 1 and wave 2 separated by an interval of 2 years and from wave 2 assessment and informant interviews, and included medical, psychiatric and ADL items and interviewers' own observations. The sample (N = 42) was derived from the first year of the wave 2 assessments, potential dementia cases entering consecutively while presumed normals were selected randomly. Informants were available in 30. Agreement on diagnosis and type of dementia improved with increasing information, particularly from informants, but remained poor regarding severity. The number of cases of dementia, defined operationally, increased from 10 to 12 and uncertain cases fell from eight to six, but no respondent initially diagnosed as a dementia case was rediagnosed as a non-case, or vice versa. Dementia type changed from agreement about Alzheimer's disease to agreement about vascular dementia in one case. Operational and algorithmic diagnoses showed good agreement. Causes of disagreement, the role of vignettes and the relevance of the results for population surveys are discussed.

Prevalence and subtypes of dementia in southern Taiwan: impact of age, sex, education, and urbanization

To determine the prevalence and subtypes of dementia in southern Taiwan, a two-phase study consisting of a phase I screening survey using the Mini-Mental Status Examination (MMSE) and a phase II diagnostic examination using the CERAD neuropsychological battery and the neurobehavioral examination was conducted. According to the household records, stratified random sampling by the degree of urbanization of the community was used, and 2915 inhabitants aged 65 and over participated in this study. The ICD-10NA criteria for dementia, NINCDS-ADRDA guidelines for Alzheimer's disease (AD), and NINDS-AIREN criteria for vascular dementia (VaD) were employed. Three hundred and ninety-eight persons who had MMSE scores below the cutoff values were recruited into the phase II study, of whom 108 had dementia. The prevalence rate (PR) of dementia was 3.7%, increasing from 1.3% in people 65-69 years old to 16.5% in people 85 years old and older. The age-standardized PR (ASPR) was 4.0%. AD (58 cases, 53.7%, PR=2.0%, ASPR=2.3%) was the most common cause of dementia, followed by VaD (25 cases, 23.1%, PR=0.9%, ASPR=0.9%), and mixed dementia (eight cases, 7.4%). After adjusting for age, sex and education using logistic regression analysis, aging was a significant risk factor for AD, VaD and total dementia. Female sex and illiteracy were significant risk factors for AD only. We concluded that the prevalence of dementia in Taiwan is lower than in the developed countries, which could be due to a relatively young elderly population and a high mortality from dementia in Taiwan. AD is the leading cause of dementia in Taiwan. Considering the high stroke prevalence, the relatively lower prevalence of VaD in Taiwan deserves further investigation.

Dementia and help with household tasks: a comparison of cases and non-cases

This paper is based on data, relating to people aged 75+ living in the community, from the city of Liverpool and from a rural area of North Wales. It compares those suffering from cognitive brain disorders with those identified as being cognitively unimpaired. Levels of need, and sources of help with a range of domestic and home maintenance tasks are identified. Results show that most help for those who are cognitively impaired comes from relatives living in the same household, while help for those who are physically impaired comes primarily from spouses or relatives living in different households. Cases do not demonstrate a higher level of use of formal services than non-cases. Implications for policy and practice are discussed.

Analysis of alpha-1 antichymotrypsin, presenilin-1, angiotensin-converting enzyme, and methylenetetrahydrofolate reductase loci as candidates for dementia

The genetic factors which predispose individuals to dementia in old age have not been fully defined. Although the apolipoprotein E4 allele accounts for a proportion of the genetic risk for late-onset Alzheimer disease (AD), it is neither necessary nor sufficient to cause this disease. Recent suggestions that other loci are involved in dementia risk have been supported by findings of associations of genotypes at the alpha-1 antichymotrypsin (ACT) and presenilin-1 (PS-1) loci with AD. We investigated these loci in two community-based aged Cambridgeshire populations: the rural Ely population (cohort 1) comprised 60 pairs of demented and nondemented elderly individuals, with a mean age of 84.2 years; and the Cambridge city population (cohort 2) comprised 81 pairs all over age 84, with a mean age of 87.3 years. Since vascular risk factors are likely to impact on dementia risk, we also examined the angiotensin-converting enzyme (ACE) and methylenetetrahydrofolate reductase (MTHFR) genes as candidates. ACE, ACT, PS-1, and MTHFR genotype and allele frequencies were not significantly different in cases and matched controls. These data support the doubts which have been raised about the involvement of the PS-1 and ACT polymorphisms in late-onset dementia.

The tRNA(Gln) 4336 mitochondrial DNA variant is not a high penetrance mutation which predisposes to dementia before the age of 75 years

The genetic factors that predispose to Alzheimer's disease (AD) are heterogeneous. Two recent reports have suggested that a mitochondrial DNA mutation within the tRNAGln gene, located at position 4336, may be a risk factor for AD, as it was found in 10/256 (3.9%) cases with AD confirmed by necropsy. Although low prevalences of this mutation were detected in non-demented subjects in both of these studies, the controls were not carefully matched with the AD cases. We have investigated the frequency of this mutation in two community based elderly cohorts in Cambridgeshire, who have participated in longitudinal studies of cognitive function. The 4336 mitochondrial mutation was detected in 8/ 443 people examined. These people were found to be non-demented at ages 74, 81, 84, 86, 89, 90, 91, and 102 years, in contrast to the previously described cases whose onset of dementia occurred between 60 and 76 years (mean 68). Accordingly, we believe that this mitochondrial variant is not a high penetrance mutation which predisposes to dementia before the age of 76 years.

A longitudinal study of factors predicting change in cognitive test scores over time, in an older hypertensive population

This study aims to describe factors associated with cognitive decline among 2584 subjects, aged 65-74, who were followed up for 54 months in the Medical Research Council Elderly Hypertension Trial (1982-1989). The subjects completed a cognitive test, the Paired Associate Learning Test (PALT), five times over this period. Decline on the PALT was associated with advanced age, male sex, rural residence, depression and low intelligence. These effects were modified by gender and level of pre-morbid intelligence. Advanced age, rural residence and number of cigarettes smoked daily were only associated with PALT decline among women of below median intelligence. The association between depression and PALT decline was only apparent in women of below median intelligence and men of above median intelligence. While these findings are consistent with other research into cognitive decline, they differ in some ways from reported risk factors for dementia, suggesting aetiological separateness. That women were more vulnerable than men to the effects of age and smoking raises the question of the impact on cognition of accelerated atherosclerosis after the menopause.

The natural history of Alzheimer's disease: a brain bank study

OBJECTIVE

To define the natural history of Alzheimer's Disease (AD), from time of clinical (presumptive) diagnosis and/or onset of symptoms to death and to describe demographic and clinical characteristics of patients with AD.

DESIGN

Retrospective medical records review.

SETTING

Regional brain bank operated by a university hospital.

PARTICIPANTS

One-hundred randomly selected, autopsy-confirmed Alzheimer's Disease patients.

MEASUREMENTS

All information pertaining to family and clinical history (diagnoses, office visits, hospitalizations), medication use, nutritional status, and clinical testing (laboratory testing, imaging, diagnostics, and psychometric testing) was abstracted. Time of onset for behavioral symptoms (e.g., anxiety, wandering, agitation) and deficits in cognitive function (e.g., recent memory, concentration, language) and activities of daily living (ADL) were also abstracted. Data was collected on-site using a laptop computer and a series of customized data entry spreadsheets. Upon completion of the data abstraction process, data was converted to a database program for query and analysis.

RESULTS

A complete natural history timeline was constructed based on the mean values observed in order to demonstrate important clinical endpoints, namely, diagnosis, institutionalization, and death. The mean time between onset of symptoms and clinical diagnosis was 32.1 months (standard deviation = 37.9 months). The interval between symptom onset and AD diagnosis was longer for patients who were less than 65 at time of diagnosis (mean = 37.6 months), female patients (mean = 34.9 months), and patients with a positive family history of dementia (mean = 37.5 months). The mean age at diagnosis was 74.7 years (standard deviation = 8.6 years), with a range of 52 to 89 years. Most patients were diagnosed between the ages of 70 and 79. Males were diagnosed at an earlier age, 72.8 years, on average, than females, 75.4 years. The mean time to institutionalization from time of clinical diagnosis was 23.9 months (standard deviation = 33.6 months). The average age at institutionalization was 77.6 years, with a minimum of 60 years and a maximum of 92.5 years. Institutionalization occurred 56.5 months after symptom onset, on average. This interval was shorter among patients with a negative family history (mean = 53.1 months) and patients diagnosed after age 65 (mean = 51.6 months). Patients diagnosed before age 65 experienced a significantly greater average time to institutionalization, 94 months (P = .01). Disease duration was measured as time from symptom onset until death. Mean disease duration was 101.3 months, or nearly 8.5 years (standard deviation = 59.2 months). Subgroup analysis showed that disease duration was prolonged in younger onset patients (mean = 129.1 months), females (mean = 107.9 months), and patients with a positive family history of dementia (mean = 106.3 months).

CONCLUSIONS

These data suggest that the typical AD patient is diagnosed 32 months after symptom onset, at the age of 75 years. This patient is institutionalized 25 months after diagnosis, or approximately 57 months after symptom onset at age 78. The patient remains institutionalized for 44 months or, in actuality, until death. Total disease duration for this typical AD patient is just over 101 months, or approximately 8.5 years.

Late-life depressive disorder in the community. II. The relationship between psychiatric history, MMSE and family history

BACKGROUND

In previous studies, dementia was linked to a family history of dementia and Down's syndrome. This study tested the hypothesis that late-life depression accompanied by cognitive impairment in elderly individuals with no history of psychiatric illness is also associated with these family histories.

METHOD

We investigated an age-stratified sample of 4051 elderly people in the community aged 65-84 (AMSTEL). The relationship between family history (CAMDEX questionnaire) and depression (GMS-AGECAT diagnosis) was studied.

RESULTS

A family history of mental health problems was associated with all subtypes of depression. Family history of dementia was associated with depression in subjects with a psychiatric history, but a family history of Down's syndrome was only associated with the combination of depression and cognitive impairment in subjects with no history of psychiatric illness.

CONCLUSIONS

The heritability pattern confirms the concept of a dementia-related subtype of late-life depression.