The natural history of dementia

This review summarizes studies on the natural history of dementia with a focus on Alzheimer's disease and vascular dementia. Understanding the course of dementia is important not only for patients, caregivers, and health professionals, but also for health policy‐makers, who have to plan for national resources needed in the management of an increasing number of dementia cases. From the available published data, the life expectancy of elderly people with dementia is shorter than that of non‐demented elderly. Reports on survival after a diagnosis of dementia vary from 3 to 12 years. The wide variation is partly due to the diagnostic criteria used in the studies and the sites where they were conducted (i.e. hospitals, clinics, or homes). There is an apparent difference in survival between Alzheimer's disease patients with onset of illness before 75 years and those after 75 years: the younger patients have a longer life expectancy. However, there are conflicting data on survival (in years) comparing male and female patients and comparing patients of different ethnicities. For vascular dementia, published papers on life expectancy vary between 3 to 5 years. Vascular dementia appears to have a poorer prognosis than Alzheimer's disease. The stages of severity of dementia were compared in a follow‐up of a sample of Alzheimer's disease patients in Singapore, and the mean duration of the mild phase (clinical dementia rating 1) was 5.6 years, the moderate phase (clinical dementia rating 2) was 3.5 years, and the severe phase (clinical dementia rating 3) was 3.2 years. At the various phases of the disease, the demand on health‐care services and economic cost are different.     

The relationship between psychiatric and physical health in elderly people with intellectual disability

Elderly people with intellectual disability have high rates of both psychiatric and physical disorders. In the elderly general population, these disorders are known to be associated. Whether such an association exists amongst elderly people with intellectual disability is unclear, but the resolution of this question is of clinical as well as academic importance. Psychiatric and physical assessments were completed on 134 people with intellectual disability aged 65 years and over (93.7% of the ascertained population living in Leicestershire, UK). The relationship between the two disorders was statistically examined. The number of physical disorders, age, level of intellectual disability and smoking status were retained in the logistic regression equation which predicted caseness for dementia in 79.9%. Similar statistical modelling for psychiatric disorders (other than dementia) retained the level of intellectual disability as the only explanatory variable in the equation. These results differ from the elderly general population, but are in keeping with the one previous intellectual disability study. In view of the poor use of general medical services by elderly people with intellectual disability, knowledge of such comorbidity should alert psychiatrists to the need for physical assessments in order to optimize health.     

Life expectancy of people with intellectual disability: a 35-year follow-up study

A 35‐year follow‐up study based on a nation‐wide population study of the life expectancy of people with intellectual disability (ID) was undertaken. The study population consisted of a total of 60969 person‐years. A prospective cohort study with mortality follow‐up for 35 years was used and the life expectancy of people with ID was calculated for different levels of intelligence. Proportional hazard models were used to assess the influence of level of intelligence and associated disorders on survival. People with mild ID did not have poorer life expectancy than the general population and subjects with mild ID did not have lower life expectancy in the first 3 decades of life. In cases with profound ID, the proportion of expected life lost was > 20% for almost all age groups. The female preponderance was manifested from the age of 60 years onwards, 25 years later than in the general population. Respectively, survival between sexes differed less. Epilepsy and/or hearing impairment increased the relative risk of death for all levels of ID. The prevalence of people with ID over 40 years was 0.4%. People with ID now live longer than previously expected, and the ageing of people with mild ID appears to be equal to that of the general population, posing new challenges to health care professionals.     

Quantification of Alzheimer pathology in ageing and dementia: age-related accumulation of amyloid-beta(42) peptide in vascular dementia

Clinicopathological observations suggest there is considerable overlap between vascular dementia (VaD) and Alzheimer's disease (AD). We used immunochemical methods to compare quantities of amyloid-beta (Abeta) peptides in post mortem brain samples from VaD, AD subjects and nondemented ageing controls. Total Abeta peptides extracted from temporal and frontal cortices were quantified using a previously characterized sensitive homogenous time-resolved fluorescence (HTRF) assay. The HTRF assays and immunocapture mass spectrometric analyses revealed that the Abeta(42) species were by far the predominant form of extractable peptide compared with Abeta(40) peptide in VaD brains. The strong signal intensity for the peak representing Abeta(4-42) peptide confirmed that these N-terminally truncated species are relatively abundant. Absolute quantification by HTRF assay showed that the mean amount of total Abeta(42) recovered from VaD samples was approximately 50% of that in AD, and twice that in the age-matched controls. Linear correlation analysis further revealed an increased accumulation with age of both Abeta peptides in brains of VaD subjects and controls. Interestingly, VaD patients surviving beyond 80 years of age exhibited comparable Abeta(42) concentrations with those in AD in the temporal cortex. Our findings suggest that brain Abeta accumulates increasingly with age in VaD subjects more so than in elderly without cerebrovascular disease and support the notion that they acquire Alzheimer-like pathology in older age.     

Dysthymic disorder in adolescents with intellectual disability

The present report examines the clinical features of dysthymic disorder in a sample of adolescents with mild intellectual disability (ID). Frequency of symptoms, comorbidity, agreement between reports of subjects and parents, comparison between the frequency of depressive symptoms in subjects with ID and in two different groups of normal IQ dysthymic subjects (aged 7–11, 11 and 12–18 years) are described. The sample consisted of 12 subjects (age range = 12–25.6 years; mean age = 16.3 years) screened from unselected consecutively referred patients with mild ID. All the subjects were comprehensively diagnosed with a structured diagnostic interview, the Kiddie-Schedule for Affective Disorder and Schizophrenia (K-SADS), according to DSM-IV criteria. A symptomatic profile in the group with ID showed that intrapsychic and cognitive symptoms, such as depressed mood, irritability, pathological guilt and low self-image, were frequently reported in people with ID. Parents were less aware of depressed mood, but they reported high rates of low self-esteem; the agreement between the depressive reports of ID subjects and their parents was higher than in previous findings in normal IQ children. The symptomatic profile of subjects with ID was more comparable to that of prepubertal dysthymic children than that of dysthymic adolescents, but more significant are the analogies between dysthymic disorder in ID and normal IQ subjects. High rates of comorbidity with generalized anxiety disorder were evident in the group with ID. According to the present data, dysthymic disorder can be diagnosed in adolescents with mild ID. The K-SADS clinical interview seems to be a reliable instrument for the diagnosis and clinical definition of depressive symptomatology in this special population.     

Diagnostic instruments for dementia in older people with intellectual disability in clinical practice

There is a need for simple and reliable screening instruments for dementia in the intellectual disability (ID) population that can also be used to follow their progress, particularly if they are being treated with anti-dementia drugs. Commonly used tests for the general population such as the Mini Mental State Examination (MMSE) are not appropriate for many people with ID. This paper is a literature review of alternative instruments that have been used in research or recommended by experts since 1991 and have the potential to be used as screening instruments. Two types of tests have been identified: those administered to informants, and those that rely on direct assessment of the individual. The most promising informant rated screening tool in most adults with ID including Down syndrome (DS) diagnosis is the Dementia Questionnaire for Persons with Mental Retardation (DMR). However, sensitivity in single assessments is variable and cut-off scores need further optimisation. In those with DS, the Dementia Scale for Down Syndrome (DSDS) has good specificity but mediocre sensitivity. The Test for Severe Impairment and Severe Impairment Battery are two direct assessment tools that show promise as screening instruments, but need further evaluation.     

Responding to the challenges of ageing and dementia in intellectual disability in Ireland

The intellectual disability (ID) population in Ireland is ageing and the number of older persons with the dual disability of ID and dementia is increasing. In spite of these demographic trends, as in other countries adequate policy and service provision for this population are lacking. This paper draws upon data available on the population with ID and dementia, reviews both generic and ID specific literature, considers the policy context and argues for a specific model of service provision. A service model is proposed for the development of multidisciplinary specialist teams within ID, delivered through mobile regional ID dementia clinics.     

Ageing in people with intellectual disability as it is understood by group home staff

Background The number of older residents in group homes for people with intellectual disability (ID) is increasing. This interview study was focused on how group home staff address issues of ageing and being old among people with ID.

Method Twelve members of staff at 4 different group homes in Sweden were interviewed.

Results Findings revealed old age as something unarticulated in the group home. Group home staff felt unprepared to meet age-related changes in residents. The study also revealed that group home staff had a one-tracked way of describing the process of ageing among people with ID, which was seemingly rooted in a medical paradigm of disability.

Conclusion Based on this study's findings, we suggest that there is a need to raise issues and give guidance related to ageing and ID in disability policy documents to support the development of a formal culture that addresses old age and ID in disability services.     

The first use of dementia care mapping in the care for older people with intellectual disability: a process analysis according to the RE-AIM framework

ABSTRACT

Introduction: The aging of the population with intellectual disability (ID), with associated conseqences as dementia, creates a need for evidence-based methods to support staff. Dementia Care Mapping (DCM) is perceived to be valuable in dementia care and promising in ID-care. The aim of this study was to evaluate the process of the first use of DCM in ID-care.

Methods: DCM was used among older people with ID and care-staff in 12 group homes of six organisations. We obtained data on the first use of DCM in ID-care via focus-group discussions and face-to-face interviews with: care-staff (N = 24), managers (N = 10), behavioural specialists (N = 7), DCM-ID mappers (N = 12), and DCM-trainers (N = 2). We used the RE-AIM framework for a thematic process-analysis.

Results: All available staff (94%) participated in DCM (reach). Regarding its efficacy, staff considered DCM valuable; it provided them new knowledge and skills. Participants intended to adopt DCM, by continuing and expanding its use in their organisations. DCM was implemented as intended, and strictly monitored and supported by DCM-trainers. As for maintenance, DCM was further tailored to ID-care and a version for individual ID-care settings was developed, both as standards for international use. To sustain the use of DCM in ID-care, a multidisciplinary, interorganisational learning network was established.

Conclusion: DCM tailored to ID-care proved to be an appropriate and valuable method to support staff in their work with aging clients, and it allows for further implementation. This is a first step to obtain an evidence-based method in ID-care for older clients.     

Medical aspects of ageing in a population with intellectual disability: III. Mobility, internal conditions and cancer

The aim of this study was to assess mobility Impairment and morbidity and mortality caused by Internal conditions and cancer in an ageing population with mild to severe intellectual disability. Seventy subjects with a mean age of 70 years (range 60–92 years) at initial evaluation, were assessed during a 10-year prospective longitudinal study. As was to be expected, there was a high prevalence of mobility impairment (30% under and 58% over age 75), similar to reports from other ageing populations with Intellectual disability, and of related conditions (chronic constipation, pulmonary function loss and urinary incontinence). Overall morbidity and mortality caused by internal disease and cancer might be comparable to that In the general ageing Dutch population, but questions concerning the specific contribution of risk factors will have to be addressed. The lack of or atypical presentation of subjective symptoms was striking. Nevertheless, autopsy outcomes showed that diagnosis in people with intellectual disability can be as accurate as In the general population, if performed actively.     

Eating disorders in adults with intellectual disability

There is an increasing focus on the nutrition of people with intellectual disability (ID), but less interest in the range of eating disorders (EDs) that they may exhibit and the bio‐psycho‐social impact of these conditions. Despite diagnostic and methodological difficulties, psychopathology and ED research studies suggest that 3–42% of institutionalized adults with ID and 1–19% of adults with ID in the community have diagnosable EDs. Weight surveys indicate that 2–35% of adults with ID are obese and 5–43% are significantly underweight, but the contribution of diagnosable EDs is unknown. Such data and case reports suggest that EDs are associated with considerable physical, behavioural, psychiatric and social comorbidity. Review papers have focused on the aetiology and treatment of pica, rumination, regurgitation, psychogenic vomiting and food faddiness/refusal. Emerging clinical issues are the development of appropriate diagnostic criteria, multimodal assessment and clinically effective treatment approaches. Key service issues include staff training to improve awareness, addressing comorbidity and access issues, and maintaining support for adults with ID and EDs, and their carers. Research should confirm the multifaceted aetiology and comorbidity of EDs. Then multicomponent assessment and treatment models for EDs can be developed and evaluated.     

Maladaptive behaviours and symptoms of dementia in adults with Down's syndrome compared with adults with intellectual disability of other aetiologies

Dementia commonly occurs in elderly people with intellectual disability, especially those with Down's syndrome. The non-cognitive symptoms of dementia can be of greater significance to individuals and carers than the cognitive changes caused by this condition. It is not known whether there are differences between people with Down's syndrome and those with intellectual disability of other causes with regard to the prevalence of such symptoms. The present study was undertaken to draw a comparison between a group with Down's syndrome and dementia ( n = 19), and a group with intellectual disability of other causes and dementia ( n = 26). Maladaptive behaviours and psychiatric symptomatology were assessed in both groups. The group with Down's syndrome had a higher prevalence of low mood, restlessness/excessive overactivity, disturbed sleep, being excessively uncooperative and auditory hallucinations. Aggression occurred with greater frequency in those subjects with intellectual disability of other causes. These findings are of epidemiological importance in terms of service planning and understanding psychiatric presentation.