Prevalence of dementia in intellectual disability using different diagnostic criteria

Use of biomarkers in the diagnosis of Alzheimer's disease in adults with intellectual disability

People with intellectual disability are a vulnerable cohort who face challenges accessing health care. Compared with the general population, people with intellectual disability have an elevated risk of developing dementia, which often presents at a younger age and with atypical symptoms. The lifelong cognitive and functional difficulties faced by people with intellectual disability further complicate the diagnostic process. Specialised intellectual disability memory services and evaluation using reliable biomarkers of neurodegeneration are needed to improve diagnostic and prognostic certainty in this group. Inadequate specialist services and paucity of research on biomarkers in this population hinders progress and impedes the delivery of adequate health care. Although cerebrospinal fluid-based biomarkers and radiological biomarkers are used routinely in the evaluation of Alzheimer's disease in the general population, biological variation within the clinically heterogenous group of people with intellectual disability could affect the clinical utility of existing biomarkers. As disease-modifying therapies become available for the treatment of early Alzheimer's disease, and hopefully other neurodegenerative conditions in the future, biomarkers will serve as gatekeepers to establish the eligibility for such therapies. Inadequate representation of adults with intellectual disability in biomarker research will result in their exclusion from treatment with disease-modifying therapies, thus perpetuating the inequity in health care that is already faced by this group. The aim of this Series paper is to summarise current evidence on the application of biomarkers for Alzheimer's disease in a population with intellectual disability (that is not attributable to Down syndrome) and suspected cognitive decline.

Dementia in Rare Genetic Neurodevelopmental Disorders: A Systematic Literature Review

BACKGROUND AND OBJECTIVES

Knowledge of young-onset Alzheimer disease in adults with Down syndrome has greatly improved clinical care. However, little is known about dementia in rare genetic neurodevelopmental disorders (RGNDs). In this review, a comprehensive overview is provided of reports on dementia and cognitive/adaptive trajectories in adults with RGNDs.

METHODS

A systematic literature review was conducted in Embase, Medline ALL, and PsycINFO on December 6, 2022. The protocol was registered in PROSPERO (CRD42021223041). Search terms for dementia, cognitive and adaptive functioning, and RGNDs were combined using generic terms and the Orphanet database. Study characteristics and descriptive data on genetic diagnosis, clinical and neuropathologic features, comorbidities, and diagnostic methods were extracted using a modified version of the Cochrane Data Extraction Template.

RESULTS

The literature search yielded 40 publications (17 cohorts, 23 case studies) describing dementia and/or cognitive or adaptive trajectories in adults with 14 different RGNDs. Dementia was reported in 49 individuals (5 cohorts, 20 cases) with a mean age at onset of 44.4 years. Diagnostics were not disclosed for half of the reported individuals (n = 25/49, 51.0%). A total of 44 different psychodiagnostic instruments were used. MRI was the most reported additional investigation (n = 12/49, 24.5%). Comorbid disorders most frequently associated with cognitive/adaptive decline were epilepsy, psychotic disorders, and movement disorders.

DISCUSSION

Currently available literature shows limited information on aging in RGNDs, with relatively many reports of young-onset dementia. Longitudinal data may provide insights into converging neurodevelopmental degenerative pathways. We provide recommendations to optimize dementia screening, diagnosis, and research.

Symptoms and age of prodromal Alzheimer's disease in Down syndrome: a systematic review and meta-analysis

The diagnostic criteria for adult-onset Alzheimer's disease (AD) in patients with Down syndrome (DS) have not been standardised. This study investigated the specific symptoms of AD in the prodromal stage of DS, the mean age at diagnosis at each stage of dementia, and the relationship between intellectual disability (ID) and dementia. PubMed, Web of Science, and Embase were searched for studies on DS, AD, early-stage disease, initial symptoms, and prodromal dementia registered between January 2012 and January 2022. We also performed a meta-analysis of the differences between the mean age at prodromal symptoms and AD diagnosis and the proportion of mild cognitive impairment in patients with mild and moderately abnormal ID. We selected 14 articles reporting the behavioural and psychological symptoms of dementia (BPSD) and memory- and language-related impairments as early symptoms of AD in patients with DS. The specific symptoms of BPSD were classified into five categories: irritability (agitation), apathy, abnormal behaviour, adaptive functioning, and sleep disturbance. The mean age at the diagnosis of prodromal symptoms and AD dementia was 52.7 and 56.2 years, respectively (mean difference, + 3.11 years; 95% CI 1.82-4.40) in the meta-analysis. The diagnosis of mild dementia tended to correlate with ID severity (odds ratio [OR], 1.38; 95% CI 0.87-2.18). The features of behaviour-variant frontotemporal dementia may be clinically confirmed in diagnosing early symptoms of DS-associated AD (DSAD). Moreover, age-appropriate cognitive assessment is important. Further studies are required to evaluate DSAD using a combination of biomarkers and ID-related data.

Validation of the German version of the DSQIID in adults with intellectual disabilities

BACKGROUND

An observer-rated screening questionnaire for dementia for people with intellectual disabilities (ID), DSQIID, was developed in the UK. So far, the German version has not yet been validated in adults with ID.

AIMS/METHODS

We validated a German version of DSQIID (DSQIID-G) among adults with ID attending a German clinic.

PROCEDURES/OUTCOMES

DSQIID-G was completed by the caregivers of 104 adults with ID at baseline (T1), 94 at six months (T2) and 83 at 12 months (T3). A Receiver Operating Curve (ROC) was used to determine the total DSQIID-G cutoff score for the best fit between sensitivity and specificity.

RESULTS

Sixteen of the 104 participants at T1 (15%) received a diagnosis of dementia. At T1, the scores among the non-dementia group ranged from 0 to 33 (mean: 6.7; SD: 7.65), and the dementia group ranged from 3 to 43 (mean: 22.12; SD: 11.6). The intergroup difference was statistically significant (W: 158; p < .001) (AUC:.89). A total score of 9 provided the best fit between sensitivity (.94) and specificity (.72).

CONCLUSIONS AND IMPLICATIONS

DSQIID-G total score can discriminate between dementia and non-dementia cases in adults with ID. A lower cutoff score with a higher sensitivity is desirable for a screening instrument.

Forensic psychiatric issues in intellectual disability

Forensic psychiatrists and neuropsychiatrists are likely to encounter individuals with intellectual disability as they are over-represented in the judicial system. These individuals may have the full range of mental illnesses and comorbid conditions, including physical infirmity, sensory deficits, language impairment, and maladaptive behaviors. They are frequently disadvantaged in the judicial system due to lack of comprehension, lack of accommodations, and stigmatization. Decision making capacity may need to be assessed for health care, sexual autonomy, marriage, financial management, making a will, and need for guardianship. The usual approach to conducting an evaluation needs adaptation to fit the unique characteristics and circumstances of the individual with intellectual disability. The forensic consultant can assist attorneys, defendants, and victims in recommending accommodations and the expert witness can provide education to juries.

Cognitive reserve proxies for individuals with intellectual developmental disability: A scoping review

BACKGROUND

Cognitive reserve (CR) has not been studied in people with Intellectual Developmental Disability, a population with a high incidence of dementia. Commonly adopted CR proxies should be adapted to reflect more specifically the experiences of people with Intellectual Developmental Disability.

METHOD

This scoping review intended to identify CR proxies relevant to people with this condition.

RESULTS

Some of these were the same already detected in a population without intellectual disabilities (education, occupation, physical activity, leisure, community and social activities); others were found to be specifically relevant for this population: type of schooling, parental educational level, environmental stimulation and living place.

CONCLUSIONS

These proxies need to be considered in studies on CR and Intellectual Developmental Disability and in clinical practice. Research on the protective effect of CR aims to encourage policies promoting lifestyle-based educational and preventive interventions and overcome participation barriers for people with Intellectual Developmental Disability.

Iatrogenic Alzheimer's disease in recipients of cadaveric pituitary-derived growth hormone

Alzheimer's disease (AD) is characterized pathologically by amyloid-beta (Aβ) deposition in brain parenchyma and blood vessels (as cerebral amyloid angiopathy (CAA)) and by neurofibrillary tangles of hyperphosphorylated tau. Compelling genetic and biomarker evidence supports Aβ as the root cause of AD. We previously reported human transmission of Aβ pathology and CAA in relatively young adults who had died of iatrogenic Creutzfeldt-Jakob disease (iCJD) after childhood treatment with cadaver-derived pituitary growth hormone (c-hGH) contaminated with both CJD prions and Aβ seeds. This raised the possibility that c-hGH recipients who did not die from iCJD may eventually develop AD. Here we describe recipients who developed dementia and biomarker changes within the phenotypic spectrum of AD, suggesting that AD, like CJD, has environmentally acquired (iatrogenic) forms as well as late-onset sporadic and early-onset inherited forms. Although iatrogenic AD may be rare, and there is no suggestion that Aβ can be transmitted between individuals in activities of daily life, its recognition emphasizes the need to review measures to prevent accidental transmissions via other medical and surgical procedures. As propagating Aβ assemblies may exhibit structural diversity akin to conventional prions, it is possible that therapeutic strategies targeting disease-related assemblies may lead to selection of minor components and development of resistance.

Common mental health disorders and cognitive decline in a longitudinal Down syndrome cohort

BACKGROUND

Down syndrome is the most common genetic cause of intellectual disability and Alzheimer's disease. In the general population, common mental disorders (CMDs), including anxiety, depression and obsessive-compulsive disorder, are linked to cognitive decline and higher risk for dementia. It is not known how CMDs affect longer-term cognitive outcomes in Down syndrome, and there is often diagnostic uncertainty in older people with Down syndrome and psychiatric comorbidity.

AIMS

To study the influence of CMDs on cognitive ability and whether they are related longitudinally to development of clinical signs of Alzheimer's disease in Down syndrome.

METHOD

We followed 115 individuals with Down syndrome, 27 of whom were diagnosed with a CMD, over approximately 3 years. Changes in cognitive and behavioural outcomes between baseline and follow-up assessment were analysed, with comparisons made between those with and without a comorbid CMD. Age, gender, apolipoprotein E status and level of intellectual disability were included as covariates.

RESULTS

No significant association between presence of a CMD and poorer performance on cognitive tasks or informant-rated decline over time was observed (P > 0.05).

CONCLUSIONS

Our results suggest that a diagnosis of a CMD does not have a significant negative effect on long-term cognitive or behavioural outcomes in individuals with Down syndrome. In individuals with stable or treated CMD, subsequent cognitive decline is likely indicative of Alzheimer's disease rather than a consequence of mental disorder.

The mismatch negativity as an index of cognitive abilities in adults with Down syndrome

Down syndrome (DS) is associated with an ultra-high risk of developing Alzheimer's disease (AD). Understanding variability in pre-AD cognitive abilities may help understand cognitive decline in this population. The mismatch negativity (MMN) is an event-related potential component reflecting the detection of deviant stimuli that is thought to represent underlying memory processes, with reduced MMN amplitudes being associated with cognitive decline. To further understand the MMN in adults with DS without AD, we explored the relationships between MMN, age, and cognitive abilities (memory, language, and attention) in 27 individuals (aged 17-51) using a passive auditory oddball task. Statistically significant MMN was present only in 18 individuals up to 41 years of age and the latency were longer than canonical parameters reported in the literature. Reduced MMN amplitude was associated with lower memory scores, while longer MMN latencies were associated with poorer memory, verbal abilities, and attention. Therefore, the MMN may represent a valuable index of cognitive abilities in DS. In combination with previous findings, we hypothesize that while MMN response and amplitude may be associated with AD-related memory loss, MMN latency may be associated with speech signal processing. Future studies may explore the potential impact of AD on MMN in people with DS.

Prevalence and modifiable risk factors for dementia in persons with intellectual disabilities

BACKGROUND

People with intellectual disability (ID) without Down syndrome (DS) are presumed to be at higher risk of developing dementia due to their lower baseline cognitive reserve. We aimed to determine the prevalence of dementia in people with ID without DS and to identify risk factors of dementia.

METHODS

This was a cross-sectional survey and multicenter study in Japan. Adults with ID without DS residing in the facilities were included. Caregivers of all participants were interviewed by medical specialists, and participants suspected of having cognitive decline were examined directly. ICD-10 criteria for dementia, DC-LD criteria for dementia, and DSM-5 criteria for neurocognitive disorders were used to diagnose dementia. The severity of ID, educational history, and comorbidities were compared by dividing the groups into those with and without dementia.

RESULTS

A total of 1831 participants were included; 118/1831 (6.44%) were diagnosed with dementia. The prevalence of dementia for each age group was 8.8%, 60-64 years; 9.0%, 65-69 years; 19.6%, 70-74 years; and 19.4%, 75-79 years. Age, severity of ID, duration of education, hypertension, depression, stroke, and traumatic brain injury were significantly associated with the presence of dementia.

CONCLUSIONS

Although the prevalence of dementia in people with ID without DS was found to be higher at a younger age than in the general population, the results of this study suggested that adequate education, prevention of head trauma and stroke, and treatments of hypertension and depression may reduce the risk of dementia. These may be potentially important modifiable risk factors for the prevention of dementia in these people.

'Experiences of patients and their informal caregivers with cognitive stimulation programs for dementia: A qualitative systematic review protocol'

INTRODUCTION

Cognitive stimulation, an individual or group intervention approach aiming to improve cognitive and social functioning among individuals with mild-to-moderate dementia, is often considered a complex intervention. The patient's experience of a complex intervention is unique and often determines its effectiveness. This proposed qualitative systematic review aims to comprehensively synthesise the experiences of individuals with dementia and their informal caregivers who have participated in cognitive stimulation programs, identifying perceived benefits, challenges, barriers, and facilitators to this approach to intervention.

METHODS

This review will consider qualitative studies that evaluate the experiences of individuals with a diagnosis of dementia and/or the informal caregivers of individuals with dementia who have participated in a cognitive stimulation program. Searches will be conducted across MEDLINE (Ovid), Embase (Elsevier), PsycINFO, Scopus, CINAHL (EBSCO) and Web of Science. Quality of eligible studies will be assessed using the JBI Critical Appraisal Checklist for Qualitative Research, and a standardised data extraction tool in JBI SUMARI will be used to extract data from relevant studies. The meta-aggregation approach will be used to pool qualitative research findings, which will then be synthesised to produce a single set of findings in narrative format.

DISCUSSION

This qualitative systematic review will identify and synthesise the evidence regarding the experiences of individuals with dementia who have taken part in a cognitive stimulation program and the experience of their informal caregivers. As a variety of cognitive stimulation programs exist, our findings will summarise the experiences of these interventions to inform the future development and delivery of cognitive stimulation programs.

TRIAL REGISTRATION

PROSPERO registration number: CRD42022383658.

Longitudinal Clinical and Cognitive Changes Along the Alzheimer Disease Continuum in Down Syndrome

IMPORTANCE

Alzheimer disease (AD) is the main medical problem in adults with Down syndrome (DS). However, the associations of age, intellectual disability (ID), and clinical status with progression and longitudinal cognitive decline have not been established.

OBJECTIVE

To examine clinical progression along the AD continuum and its related cognitive decline and to explore the presence of practice effects and floor effects with repeated assessments.

DESIGN, SETTING, AND PARTICIPANTS

This is a single-center cohort study of adults (aged >18 years) with DS with different ID levels and at least 6 months of follow-up between November 2012 and December 2021. The data are from a population-based health plan designed to screen for AD in adults with DS in Catalonia, Spain. Individuals were classified as being asymptomatic, having prodromal AD, or having AD dementia.

EXPOSURES

Neurological and neuropsychological assessments.

MAIN OUTCOMES AND MEASURES

The main outcome was clinical change along the AD continuum. Cognitive decline was measured by the Cambridge Cognitive Examination for Older Adults With Down Syndrome and the modified Cued Recall Test.

RESULTS

A total of 632 adults with DS (mean [SD] age, 42.6 [11.4] years; 292 women [46.2%]) with 2847 evaluations (mean [SD] follow-up, 28.8 [18.7] months) were assessed. At baseline, there were 436 asymptomatic individuals, 69 patients with prodromal AD, and 127 with AD dementia. After 5 years of follow-up, 17.1% (95% CI, 12.5%-21.5%) of asymptomatic individuals progressed to symptomatic AD in an age-dependent manner (0.6% [95% CI, 0%-1.8%] for age <40 years; 21.1% [95% CI, 8.0%-32.5%] for age 40-44 years; 41.4% [95% CI, 23.1%-55.3%] for age 45-49 years; 57.5% [95% CI, 38.2%-70.8%] for age ≥50 years; P < .001), and 94.1% (95% CI, 84.6%-98.0%) of patients with prodromal AD progressed to dementia with no age dependency. Cognitive decline in the older individuals was most common among those who progressed to symptomatic AD and symptomatic individuals themselves. Importantly, individuals with mild and moderate ID had no differences in longitudinal cognitive decline despite having different performance at baseline. This study also found practice and floor effects, which obscured the assessment of longitudinal cognitive decline.

CONCLUSIONS AND RELEVANCE

This study found an association between the development of symptomatic AD and a high risk of progressive cognitive decline among patients with DS. These results support the need for population health plans to screen for AD-related cognitive decline from the fourth decade of life and provide important longitudinal data to inform clinical trials in adults with DS to prevent AD.

Individual cognitive stimulation therapy (iCST) for people with intellectual disability and dementia: a feasibility randomised controlled trial

OBJECTIVES

To examine the feasibility, acceptability and fidelity of individual Cognitive Stimulation Therapy (iCST) in people with intellectual disability (ID) and dementia.

METHOD

We aimed to recruit forty dyads (carer and individual with dementia and ID) who were randomised to iCST or a waiting list control group. Both groups received treatment as usual. Family and paid carers delivered the manualised intervention (40 sessions over 20 weeks). Recruitment and retention of participants, intervention adherence, fidelity and acceptability were assessed. Outcome measures of cognition, adaptive functioning, quality of life (QoL) and carer outcomes were collected at baseline, midpoint (11 weeks) and at 21 weeks. Qualitative interviews were conducted with six carers about their experience of iCST.

RESULTS

Forty dyads were recruited over 10 months from 12 National Health Service trusts. One dyad dropped out and 87.5% and 97.5% completed the midpoint and end-point assessments respectively. Assessment of fidelity indicated that the correct session structure was not followed; 70% completed at least 20 sessions and there was a high level of satisfaction with iCST. QoL was significantly higher in the iCST arm at 21 weeks (adjusted mean difference: 3.11; 95% CI: 0.64 to 5.58). There were no differences in the other outcome measures.

CONCLUSION

The intervention was feasible and acceptable. A full-scale trial is warranted but some modifications are needed, including improved training and supervision for carers to improve fidelity.

The prevalence and incidence of early-onset dementia among adults with autism spectrum disorder

The prevalence and incidence of early-onset dementia among adults with autism spectrum disorder (ASD) is currently unknown. In this case-control study, the prevalence and incidence of early-onset dementia in individuals with ASD was examined during 2008-2012 using Medicaid Analytic eXtract files. Participants were 30-64 year-old adults who were Medicaid beneficiaries and had either a diagnosis of ASD only (n = 12,648), a diagnosis of ASD with co-occurring intellectual disability (ID) (n = 26,168), a diagnosis of ID without ASD (n = 406,570), or no ASD nor ID diagnoses (n = 798,828). The 5-year prevalence of dementia was 4.04% among adults with ASD only, and 5.22% for those with ASD and co-occurring ID. This prevalence was higher compared to the prevalence of dementia in individuals with no ASD and no ID (0.97%), but lower compared to individuals with ID only (7.10%). Risk factors associated with the increased prevalence in the general population were similarly associated with the increased risk of dementia in individuals with ASD. Even after adjusting for these risk factors, compared to the general population, dementia was found to occur more frequently in individuals with ASD only (adjusted hazard ratio, 1.96; 95% CI, 1.69-2.28), as well as individuals with ASD and co-occurring ID (adjusted hazard ratio, 2.89; 95% CI, 2.62-3.17). In conclusion, adults with ASD under the age of 65 were approximately 2.6 times more likely to be diagnosed with dementia compared to the general population in our study. LAY SUMMARY: It is unclear whether adults diagnosed with autism spectrum disorder (ASD) are at higher risk of being diagnosed with early-onset dementia compared to those who are not on the autism spectrum. In this study we examined for the first time the nationwide prevalence and incidence of Alzheimer's Disease and other types of dementia in ASD in a sample of adults with ASD aged 30-64 years who were enrolled in Medicaid, the largest insurer of behavioral health services in the US. Medicaid claims data, which include information on the diagnoses that beneficiaries receive, suggested that the adults with ASD were approximately 2.6 times more likely to be diagnosed with early-onset Alzheimer's disease and related dementias compared to the general population.

Cognitive and Behavioral Domains That Reliably Differentiate Normal Aging and Dementia in Down Syndrome

Primary care integration of Down syndrome (DS)-specific dementia screening is strongly advised. The current study employed principal components analysis (PCA) and classification and regression tree (CART) analyses to identify an abbreviated battery for dementia classification. Scale- and subscale-level scores from 141 participants (no dementia n = 68; probable Alzheimer’s disease n = 73), for the Severe Impairment Battery (SIB), Dementia Scale for People with Learning Disabilities (DLD), and Vineland Adaptive Behavior Scales—Second Edition (Vineland-II) were analyzed. Two principle components (PC1, PC2) were identified with the odds of a probable dementia diagnosis increasing 2.54 times per PC1 unit increase and by 3.73 times per PC2 unit increase. CART analysis identified that the DLD sum of cognitive scores (SCS < 35 raw) and Vineland-II community subdomain (<36 raw) scores best classified dementia. No significant difference in the PCA versus CART area under the curve (AUC) was noted (D(65.196) = −0.57683; p = 0.57; PCA AUC = 0.87; CART AUC = 0.91). The PCA sensitivity was 80% and specificity was 70%; CART was 100% and specificity was 81%. These results support an abbreviated dementia screening battery to identify at-risk individuals with DS in primary care settings to guide specialized diagnostic referral.

Cause of death in adults with intellectual disability in the United States

BACKGROUND

Prior studies report that adults with intellectual disability (ID) have cause of death patterns distinct from adults in the general population but do not provide comparative analysis by specific causes of death.

METHODS

Data are from the National Vital Statistics System 2005-2017 US Multiple Cause-of-Death Mortality files. We utilised adjusted odds ratios to identify causes of death that were more common for adults whose death certificate indicated ID (N = 22 512) than for adults whose death certificate did not indicate ID (N = 32 738 229), controlling for severity level of ID. We then examine the associations between biological sex and race-ethnicity and causes of death solely among adults with ID.

RESULTS

The leading cause of death for adults with and without ID indicated on their death certificate was heart disease. Adults with ID, regardless of the severity of the disability, had substantially higher risk of death from pneumonitis, influenza/pneumonia and choking. Adults with mild/moderate ID also had higher risk of death from diabetes mellitus. Differences in cause of death trends were associated with biological sex and race-ethnicity.

CONCLUSIONS

Efforts to reduce premature mortality for adults with ID should attend to risk factors for causes of death typical in the general population such as heart disease and cancer, but also should be cognisant of increased risk of death from choking among all adults with ID, and diabetes among adults with mild/moderate ID. Further research is needed to better understand the factors determining comparatively lower rates of death from neoplasms and demographic differences in causes of death among adults with ID.

Validation of the Japanese version of the Dementia Screening Questionnaire for Individuals with Intellectual Disabilities

BACKGROUND

Dementia in people with intellectual disabilities (IDs) is difficult to detect because of preexisting cognitive deficits. An effective screening method is required. The Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) was developed as an observer rating tool to screen dementia in people with ID. The aim of this study was to verify the screening accuracy of the DSQIID for Japanese people with ID.

METHODS

Four-hundred ninety-three subjects with ID participated in this study. Caregivers who had observed the participants for more than 2 years scored the Japanese version of the DSQIID (DSQIID-J) of the participants. Three doctors examined participants directly and diagnosed dementia using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. To identify the key screening items that predict dementia, the specificities of a single and pairs of items with 100% sensitivity were evaluated relative to the dementia diagnosis.

RESULTS

Of 493 participants, 34 were people with Down syndrome (DS), and 459 were people without DS. Seventeen participants were diagnosed with dementia. The suitable cut-off score of the DSQIID-J was 10/11 (sensitivity 100% and specificity 96.8%) for screening dementia. The inter-rater reliability, test-retest reliability and internal consistency of the DSQIID-J were excellent. Regarding key items, there was no single item with 100% sensitivity, and the best two-item combination was the pair of 'Cannot dress without help' and 'Walks slower' (sensitivity 100% and specificity 93.5%).

CONCLUSIONS

We identified several important question items of the DSQIID-J related to the diagnosis of dementia in people with ID. The DSQIID-J is a useful screening tool for dementia in adults with ID.

Screening of Cognitive Changes in Adults with Intellectual Disabilities: A Systematic Review

Background and Aims: Screening and assessment of cognitive changes in adults with Intellectual Disabilities (ID), mainly Down Syndrome (DS), is crucial to offer appropriate services to their needs. We present a systematic review of the existing instruments assessing dementia, aiming to support researchers and clinicians’ best practice. Methods: Searches were carried out in the databases Web of Science; PubMed; PsycINFO in March 2019 and updated in October 2020. Studies were selected and examined if they: (1) focused on assessing age-related cognitive changes in persons with ID; (2) included adults and/or older adults; (3) included scales and batteries for cognitive assessment. Results: Forty-eight cross-sectional studies and twenty-seven longitudinal studies were selected representing a total sample of 6451 participants (4650 DS and 1801 with other ID). In those studies, we found 39 scales, questionnaires, and inventories, and 13 batteries for assessing cognitive and behavioural changes in adults with DS and other ID. Conclusion: The most used instrument completed by an informant or carer was the Dementia Questionnaire for Learning Disabilities (DLD), and its previous versions. We discuss the strengths and limitations of the instruments and outline recommendations for future use.

Association between dementia and depression: a retrospective study using the Korean National Health Insurance Service-National Sample Cohort database

OBJECTIVES

Dementia is common in people over the age of 65 years, with 80% of people with dementia older than 75 years. Previous studies have linked dementia to late-life depression, but the association between dementia and mid-life depression is poorly understood. Depression is a preventable and treatable medical condition, which means it is a modifiable factor that can potentially prevent or delay dementia. This study aimed to identify the association between dementia and depression within the life course.

DESIGN

A nationwide, retrospective propensity score matched cohort study associating dementia with depression. Depression diagnosed between the ages of 45 and 64 years was classified as 'mid-life' and 'late-life' if diagnosed at 65 years or older. Patients were considered to have depression when one or more International Statistical Classification of Diseases and Related Health Problems, 10th revision codes for depression were recorded as primary or secondary diagnosis.

SETTING

National Health Insurance Service-National Sample Cohort database of the National Health Insurance Service in South Korea, containing patient data from 2002 to 2013.

PARTICIPANTS

The study included 1824 and 374 852 patients in the case and control groups, respectively. A logistic regression analysis with complex sampling design was performed after adjusting for covariates, using the propensity score matching method without callipers, with a 1:1 nearest neighbour matching algorithm.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association of mid-onset and late-onset depression with dementia in terms of sociodemographic characteristics, such as sex and age, within the Korean population.

RESULTS

Dementia was significantly associated with the presence of depression (OR=2.20, 95% CI=1.53-3.14); in particular, female patients with depression and patients aged 45-64 years with depression had increased odds of dementia (OR=2.65, 95% CI=1.78-3.93 and OR=2.72, 95% CI=1.41-5.24, respectively) CONCLUSION: Depression is an associated factor for dementia, especially among people aged 45-64 years (mid-life).

Down syndrome and dementia: advances in the field

PURPOSE OF REVIEW

People with Down syndrome represent the world's largest population with a genetic risk for Alzheimer's disease. This review will provide a short summary of what is known and will include recent findings from the field.

RECENT FINDINGS

There has been an increasing focus on biomarker research in this population, with a number of studies presenting findings on promising new markers - Neurofilament Light (NfL) appears to be one such promising marker that has emerged. Imaging studies have increased our knowledge on the progression of Alzheimer's disease in this population.

SUMMARY

The inclusion of people with Down syndrome in dementia research is vital from a scientific and an equity perspective. Recent advances in the field can have further impact with multisite, cross country collaborative efforts. For this to happen, instruments need to be validated across language and cultures.

Prevalence of dementia in people with intellectual disabilities: Cross-sectional study

BACKGROUND

There are only a few studies of the prevalence of dementia in people with intellectual disability (ID) without Down syndrome (DS), and there is a large difference in the prevalences between reported studies. Moreover, the prevalence of mild cognitive impairment (MCI) in ID has not been reported. We aimed to evaluate the prevalence of dementia in adults of all ages and the prevalence of MCI in people with ID. Furthermore, we tried to clarify the differences depending on the various diagnostic criteria.

METHODS

The survey included 493 adults with ID at 28 facilities in Japan. The caregivers answered a questionnaire, and physicians directly examined the participants who were suspected of cognitive decline. Dementia and MCI were diagnosed according to ICD-10, DC-LD, and DSM-5 criteria.

RESULTS

The prevalence of dementia was 0.8% for the 45 to 54 years old group, 3.5% for the 55 to 64 years old group, and 13.9% for the 65 to 74 years old group in people with ID without DS. The prevalence of MCI was 3.1% for patients 45 to 54, 3.5% for patients 55 to 64, and 2.8% for patients 65 to 74 with ID without DS. DSM-5 was the most inclusive in diagnosing dementia and MCI in people with ID.

CONCLUSIONS

People with ID without DS may develop dementia and MCI at an earlier age and higher rate than the general population. Among the diagnostic criteria, DSM-5 was the most useful for diagnosing their cognitive impairment.

A Novel Framework to Measure Executive Function in Down Syndrome With Applications for Early Clinical Diagnosis of Dementia

Executive function (EF) decline is a consistent early sign of Alzheimer's disease (AD) among adults with Down syndrome (DS), which means that baseline measures of EF for individuals with DS are vital to allow detection of meaningful decline. We developed a framework to extract measures of three core components of EF (memory updating, inhibitory, and temporal components) within one task. Increases in memory load, inhibitory load, and temporal demands led to significant increases in reaction times and significant decreases in accuracy among 18 adults with DS and 18 typically developing matched individuals; thus, the expected effects of all three manipulations were detected. Good test-retest reliability indicated that this framework has the potential to provide a simple, baseline EF measure for individuals with DS.

Down Syndrome, Ageing and Epigenetics

During the past decades, life expectancy of subjects with Down syndrome (DS) has greatly improved, but age-specific mortality rates are still important and DS subjects are characterized by an acceleration of the ageing process, which affects particularly the immune and central nervous systems. In this chapter, we will first review the characteristics of the ageing phenomenon in brain and in immune system in DS and we will then discuss the biological hallmarks of ageing in this specific population. Finally, we will also consider in detail the knowledge on epigenetics in DS, particularly DNA methylation.

Effects of Dementia Care Mapping on well-being and quality of life of older people with intellectual disability: A quasi-experimental study

Background

The ageing of people with intellectual disability, accompanied with consequences like dementia, challenges intellectual disability‐care staff and creates a need for supporting methods, with Dementia Care Mapping (DCM) as a promising possibility. This study examined the effect of DCM on the quality of life of older people with intellectual disability.

Methods

We performed a quasi‐experimental study in 23 group homes for older people with intellectual disability in the Netherlands, comparing DCM (n = 113) with care‐as‐usual (CAU; n = 111). Using three measures, we assessed the staff‐reported quality of life of older people with intellectual disability.

Results

DCM achieved no significantly better or worse quality of life than CAU. Effect sizes varied from 0.01 to −0.22. Adjustments for covariates and restriction of analyses to people with dementia yielded similar results.

Conclusion

The finding that DCM does not increase quality of life of older people with intellectual disability contradicts previous findings and deserves further study.

Cognitive markers of preclinical and prodromal Alzheimer's disease in Down syndrome

INTRODUCTION

Down syndrome (DS) is associated with an almost universal development of Alzheimer's disease. Individuals with DS are therefore an important population for randomized controlled trials to prevent or delay cognitive decline, though it is essential to understand the time course of early cognitive changes.

METHODS

We conducted the largest cognitive study to date with 312 adults with DS to assess age-related and Alzheimer's disease-related cognitive changes during progression from preclinical to prodromal dementia, and prodromal to clinical dementia.

RESULTS

Changes in memory and attention measures were most sensitive to early decline. Resulting sample size calculations for randomized controlled trials to detect significant treatment effects to delay decline were modest.

DISCUSSION

Our findings address uncertainties around the development of randomized controlled trials to delay cognitive decline in DS. Such trials are essential to reduce the high burden of dementia in people with DS and could serve as proof-of-principle trials for some drug targets.

Perspectives on ethnic and racial disparities in Alzheimer's disease and related dementias: Update and areas of immediate need

Alzheimer's disease and related dementias (ADRDs) are a global crisis facing the aging population and society as a whole. With the numbers of people with ADRDs predicted to rise dramatically across the world, the scientific community can no longer neglect the need for research focusing on ADRDs among underrepresented ethnoracial diverse groups. The Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART; alz.org/ISTAART) comprises a number of professional interest areas (PIAs), each focusing on a major scientific area associated with ADRDs. We leverage the expertise of the existing international cadre of ISTAART scientists and experts to synthesize a cross-PIA white paper that provides both a concise "state-of-the-science" report of ethnoracial factors across PIA foci and updated recommendations to address immediate needs to advance ADRD science across ethnoracial populations.

Caregiving, intellectual disability, and dementia: Report of the Summit Workgroup on Caregiving and Intellectual and Developmental Disabilities

INTRODUCTION

A specially commissioned working group produced a report on caregiving, intellectual and developmental disabilities (IDDs), and dementia for the National Institutes of Health-located National Research Summit on Care, Services, and Supports for Persons with Dementia and Their Caregivers.

METHODS

Experts in caregiving, dementia, and IDDs examined the current state of research, policy, and practice related to caregiving and supports; identified the similarities and dissimilarities between IDD-related care and services and the general population affected by dementia; and considered how these findings might contribute to the conversation on developing a dementia care research and services development agenda.

RESULTS

Five major areas related to programs and caregiving were assessed: (1) challenges of dementia; (2) family caregiving interventions; (3) supportive care settings; (4) effects of diversity; and (5) bridging service networks of aging and disability.

DISCUSSION

Recommendations included increasing supports for caregivers of adults with IDDs and dementia; increasing research on community living settings and including caregivers of persons with IDDs in dementia research; acknowledging cultural values and practice diversity in caregiving; increasing screening for dementia and raising awareness; and leveraging integration of aging and disability networks.

Aging related cognitive changes associated with Alzheimer's disease in Down syndrome

OBJECTIVE

Individuals with Down syndrome (DS) have an extremely high genetic risk for Alzheimer's disease (AD), however, the course of cognitive decline associated with progression to dementia is ill-defined. Data-driven methods can estimate long-term trends from cross-sectional data while adjusting for variability in baseline ability, which complicates dementia assessment in those with DS.

METHODS

We applied an event-based model to cognitive test data and informant-rated questionnaire data from 283 adults with DS (the largest study of cognitive functioning in DS to date) to estimate the sequence of cognitive decline and individuals' disease stage.

RESULTS

Decline in tests of memory, sustained attention/motor coordination, and verbal fluency occurred early, demonstrating that AD in DS follows a similar pattern of change to other forms of AD. Later decline was found for informant measures. Using the resulting staging model, we showed that adults with a clinical diagnosis of dementia and those with APOE 3:4 or 4:4 genotype were significantly more likely to be staged later, suggesting that the model is valid.

INTERPRETATION

Our results identify tests of memory and sustained attention may be particularly useful measures to track decline in the preclinical/prodromal stages of AD in DS whereas informant-measures may be useful in later stages (i.e. during conversion into dementia, or postdiagnosis). These results have implications for the selection of outcome measures of treatment trials to delay or prevent cognitive decline due to AD in DS. As clinical diagnoses are generally made late into AD progression, early assessment is essential.

Cerebral vasoreactivity and intima-media thickness in Down syndrome: A case-control study

Subjects with Down Syndrome (DS) have high prevalence of cerebral vascular amyloidosis, cognitive decline and dementia. In Alzheimer Disease, impaired vasoreactivity has been reported as the results of vascular amyloid deposition. Aim of our study was to verify presence of impaired cerebral vasoreactivity and to study carotid intima media-thickness (IMT) by carotid and transcranial ultrasound. We studied 25 DS and compared them with 25 age- and sex-matched normal controls. Vasomotor reactivity was evaluated by means of breath-holding index (BHI) test. There was no difference in IMT, both considering the two side separately (left: 0.70±0.10 vs 0.69±0.12mm, p=0.6) (right: 0.67±0.13 vs 0.68±0.10mm, p=0.5), and considering the sum of both sides (1.38±0.22 vs 1.38±0.23mm, p=1). There was a significant difference in peak systolic velocities (PSV) (139.75±27.67 vs. 123.89±25.73cm/s, p=0.04) and in pulsatility index (PI) (0.95±0.14 vs. 0.86±0.12, p=0.02). BHI was significantly lower in DS than in controls (1.15±0.38 vs 1.88±0.72, p<0.001). In conclusion, subjects with DS have increased PSV and PI, and show a reduction of BHI, expression of impaired vasomotor reserve, possibly due to micro-vascular impairment. Larger study with longitudinal design is needed to verify our data.

Clinical aspects and biomarkers of Alzheimer's disease in Down syndrome

Alzheimer's disease (AD) may affect in excess of 90% of individuals with Down syndrome (DS) after age 60, due to duplication of the APP gene in trisomy of chromosome 21, with neuropathology that is comparable to Sporadic AD and Familial AD (FAD). Previous literature suggested some unique features in clinical presentation of dementia in DS (DSd), which might be due to diagnostic difficulties, or represent a real difference compared to SAD or FAD. We review current knowledge on clinical diagnosis and presentation of dementia in DS in comparison with FAD due to APP mutations and APP duplication. We suggest that the clinical presentation in DS (prominent memory decline and behavioral symptoms, and early development of myoclonus and seizures) are similar to the clinical features associated with APP mutations that is known to have an increased Aβ42/ Aβ40 ratio, and highlight the relative lack of vascular complications associated with cerebral amyloid angiopathy in DS in comparison with those rare individuals with FAD due to duplication APP. We consider the biomarker evidence associated with DS and DSd with reference to Aβ peptide levels and oxidative stress, and suggest future directions for research to explore the potential mechanisms associated with the clinical presentation of DSd.

Personality and behavioural changes do not precede memory problems as possible signs of dementia in ageing people with Down syndrome

OBJECTIVE

The objective was to find out whether changes in personality and adaptive functioning or memory processes decline first in ageing people with Down syndrome.

METHODS

We measured these variables cross-sectionally in a Dutch sample (22 to 62 years of age) of 68 institutionalised people with Down syndrome.

RESULTS

The scores on all the variables except one of the temperament scales were found to decline gradually with increasing age, but deterioration of episodic memory started earlier.

CONCLUSIONS

We argued that a subset of our sample suffered from dementia. Furthermore, the data suggested that immediate memory impairment is one of the earliest signs of the disease in people with Down syndrome, just as it is in the general population. Copyright © 2016 John Wiley & Sons, Ltd.

Cerebrovascular pathology in Down syndrome and Alzheimer disease

People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD) with age. Typically, by age 40 years, most people with DS have sufficient neuropathology for an AD diagnosis. Interestingly, atherosclerosis and hypertension are atypical in DS with age, suggesting the lack of these vascular risk factors may be associated with reduced cerebrovascular pathology. However, because the extra copy of APP leads to increased beta-amyloid peptide (Aβ) accumulation in DS, we hypothesized that there would be more extensive and widespread cerebral amyloid angiopathy (CAA) with age in DS relative to sporadic AD. To test this hypothesis CAA, atherosclerosis and arteriolosclerosis were used as measures of cerebrovascular pathology and compared in post mortem tissue from individuals with DS (n = 32), sporadic AD (n = 80) and controls (n = 37). CAA was observed with significantly higher frequencies in brains of individuals with DS compared to sporadic AD and controls. Atherosclerosis and arteriolosclerosis were rare in the cases with DS. CAA in DS may be a target for future interventional clinical trials.

Cohort profile: a data linkage cohort to examine health service profiles of people with intellectual disability in New South Wales, Australia

PURPOSE

People with intellectual disability are a minority group who experience poorer physical and mental health than the general population and have difficulty accessing healthcare services. There is lack of knowledge about healthcare service needs and gaps experienced by people with intellectual disability. This study aims to interrogate a large linked administrative data set containing hospital admissions, presentations to emergency departments (ED) and mortality data to provide evidence to inform the development of improved health and mental health services for this population.

PARTICIPANTS

A retrospective cohort of people with intellectual disability (n=51 452) from New South Wales (NSW), Australia, to explore health and mental health profiles, mortality, pattern of health service use and associated costs between 2005 and 2013. The cohort is drawn from: the Disability Services Minimum Data Set; Admitted Patients Data Collection; Emergency Department Data Collection, Australian Bureau of Statistics Death Registry and Registry of Births, Deaths and Marriages. Mental health service usage among those with intellectual disability will be compared to a cohort of people who used mental health services (n=1 073 139) and service usage other than for mental health will be compared with published data from the general population.

FINDINGS TO DATE

The median age of the cohort was 24 at the time of the last hospital admission and 21 at the last ED presentation. The cohort has a higher proportion of men than women and accounts for 0.6% of the NSW population in 2011. Over 70% had up to 5 ED presentations and hospitalisations between 2005 and 2012. A high proportion of people with intellectual disability live in the most disadvantaged neighbourhoods.

FUTURE PLANS

Results will be used to inform the development of more responsive healthcare, including improved interactions between health, social and disability supports. More generally, the results will assist the development of more inclusive policy frameworks for people with intellectual disability.

Use of antipsychotics, benzodiazepine derivatives, and dementia medication among older people with intellectual disability and/or autism spectrum disorder and dementia

BACKGROUND

Although people with intellectual disability (ID) and people with dementia have high drug prescription rates, there is a lack of studies investigating drug use among those with concurrent diagnoses of ID and dementia.

AIM

To investigate the use of antipsychotics, benzodiazepine derivatives, and drugs recommended for dementia treatment (anticholinesterases [AChEIs] and memantine) among people with ID and dementia.

METHODS AND PROCEDURES

Having received support available for people with ID and/or autism spectrum disorder (ASD) was used as a proxy for ID. The ID cohort consisted of 7936 individuals, aged at least 55 years in 2012, and the referent cohort of age- and sex-matched people from the general population (gPop). People with a specialists' diagnosis of dementia during 2002-2012 were identified (ID, n=180; gPop, n=67), and data on prescription of the investigated drugs during the period 2006-2012 were collected.

OUTCOME AND RESULTS

People with ID/ASD and dementia were more likely than people with ID/ASD but without dementia to be prescribed antipsychotics (50% vs 39% over the study period; odds ratio (OR) 1.85, 95% confidence interval 1.13-30.3) and benzodiazepine derivatives (55% vs 36%; OR 2.42, 1.48-3.98). They were also more likely than people with dementia from the general population to be prescribed antipsychotics (50% vs 25%; OR 3.18, 1.59-6.34), but less likely to be prescribed AChEIs (28% vs 45%; OR 0.32, 0.16-0.64).

The LonDownS adult cognitive assessment to study cognitive abilities and decline in Down syndrome

Background: Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with an ultra-high risk of developing Alzheimer’s disease. However, there is individual variability in the onset of clinical dementia and in baseline cognitive abilities prior to decline, particularly in memory, executive functioning, and motor coordination. The LonDownS Consortium aims to determine risk and protective factors for the development of dementia and factors relating to cognitive abilities in people with DS. Here we describe our cognitive test battery and related informant measures along with reporting data from our baseline cognitive and informant assessments.

Methods: We developed a cognitive test battery to assess general abilities, memory, executive function, and motor coordination abilities in adults with DS, with informant ratings of similar domains also collected, designed to allow for data on a broad range of participants. Participants (n=305) had a range of ages and abilities, and included adults with and without a clinical diagnosis of dementia.

Results: Results suggest the battery is suitable for the majority of adults with DS, although approximately half the adults with dementia were unable to undertake any cognitive task. Many test outcomes showed a range of scores with low floor and ceiling effects. Non-verbal age-adjusted IQ scores had lower floor effects than verbal IQ scores. Before the onset of any cognitive decline, females aged 16-35 showed better verbal abilities compared to males. We also identified clusters of cognitive test scores within our battery related to visuospatial memory, motor coordination, language abilities, and processing speed / sustained attention.

Conclusions: Our further studies will use baseline and longitudinal assessments to explore factors influencing cognitive abilities and cognitive decline related to ageing and onset of dementia in adults with DS.

An Exploratory Study Investigating How Adults with Intellectual Disabilities Perform on the Visual Association Test (VAT)

BACKGROUND

Neuropsychological tests of memory are believed to offer the greatest sensitivity at identifying people at the risk of developing dementia. There is a paucity of standardized and appropriate neuropsychological assessments of memory for adults with an intellectual disability. This study examines how adults with an intellectual disability perform on the Visual Association Test (VAT).

METHODS

Forty participants (18-45 years) with intellectual disability, without a diagnosis of dementia, completed the VAT and subtests of the CAMCOG-DS. Correlational analysis of the test variables was carried out.

RESULTS

All participants performed well on the VAT irrespective of age, gender or IQ. No significant correlations were found between the VAT and the subtests of the CAMCOG-DS.

CONCLUSIONS

The VAT was found to be an easy and quick test to use with people with intellectual disability and all participants scored above 'floor' level.

An evaluation of a Singing for the Brain pilot with people with a learning disability and memory problems or a dementia

This paper presents the findings from a pilot project introducing Singing for the Brain into care centres with people with a learning disability and a form of dementia or memory problem. Through participant observations, patient and staff feedback, there was strong support for the use of Singing for the Brain with this client group, with participants reporting high levels of enjoyment and engagement in the sessions. The potential for these sessions to support communication, memory, social engagement and choice was reported by staff and participants. Whilst anecdotal reports also suggested the sessions had a positive impact on elevating mood over a sustained period of time. The pilot sessions are discussed in reference to the regular sessions run for people with dementia and comparisons drawn across the two approaches. Further evidence is required to understand the potential impact on participant’s well-being from attending these sessions.

A critical literature review of the effectiveness of various instruments in the diagnosis of dementia in adults with intellectual disabilities

Introduction

Currently, there is no consensus on dementia diagnostics in adults with intellectual disabilities (ID). There are three types of assessments available: direct cognitive tests, test batteries, and informant reports.

Methods

A systematic literature search was conducted in four databases yielding 9840 records. Relevant studies were identified and selected using predefined inclusion and exclusion criteria and then coded and classified according to assessment type. This was completed by two independent researchers, with a third consulted when discrepancies arose. The review collates diagnostic instruments and presents strengths and weaknesses.

Results

Overall 47 studies met the search criteria, and 43 instruments were extracted from the selected studies. Of which, 10 instruments were classified as test batteries, 23 were classified as direct cognitive tests, and the remaining 10 were informant reports.

Discussion

This review can recommend that cognitive test batteries can offer the most practical and efficient method for dementia diagnosis in individuals with ID.

Assessing Specific Cognitive Deficits Associated with Dementia in Older Adults with Down Syndrome: Use and Validity of the Arizona Cognitive Test Battery (ACTB)

Background

Down syndrome is associated with specific cognitive deficits. Alongside this, older adults with Down syndrome are a high risk group for dementia. The Arizona Cognitive Test Battery (ACTB), a cognitive assessment battery specifically developed for use with individuals with Down syndrome, has been proposed for use as outcome measures for clinical trials in this population. It has not been validated in older adults with Down syndrome. This study aims to assess the use and validity of the ACTB in older adults with Down syndrome.

Methods

Participants with Down syndrome aged 45 and over were assessed using the ACTB, standard tabletop tests and informant ratings.

Results

Assessment outcomes of 49 participants were analysed. Of these, 19 (39%) had a diagnosis of dementia or possible dementia. Most participants were able to attempt most of the tasks, although some tasks had high floor effects (including CANTAB Intra-Extra Dimensional shift stages completed and Modified Dots Task). Of the ACTB tasks, statistically significant differences were observed between the dementia and no dementia groups on CANTAB Simple Reaction Time median latency, NEPSY Visuomotor Precision—Car and Motorbike and CANTAB Paired Associates Learning stages completed. No significant differences were observed for CANTAB Intra-Extra Dimensional Shift, Modified Dots Task, Finger Sequencing, NEPSY Visuomotor precision—Train and Car and CANTAB Paired Associates Learning first trial memory score. Several of the tasks in the ACTB can be used in older adults with Down syndrome and have mild to moderate concurrent validity when compared to tabletop tests and informant ratings, although this varies on a test by test basis.

Conclusions

Overall, scores for a number of tests in the ACTB were similar when comparing dementia and no dementia groups of older adults with Down syndrome, suggesting that it would not be an appropriate outcome measure of cognitive function for clinical trials of dementia treatments without further modification and validation.

"Intellectual developmental disorders": reflections on the international consensus document for redefining "mental retardation-intellectual disability" in ICD-11

PURPOSE

The debate as to whether intellectual disability (ID) should be conceptualized as a health condition or as a disability has intensified as the revision of World Health Organization's (WHO's) International Classification of Diseases (ICD) is being finalized. Defining ID as a health condition is central to retaining it in ICD, with significant implications for health policy and access to health services. The purpose of this paper is to include some reflections on the consensus document produced by the first WHO Working Group on the Classification of MR (WHO WG-MR) and on the process that was followed to realize it. The consensus report was the basis for the development of official recommendations sent to the WHO Advisory Group for ICD-11.

DESIGN/METHODOLOGY/APPROACH

A mixed qualitative approach was followed in a series of meetings leading to the final consensus report submitted to the WHO Advisory group. These recommendations combined prior expert knowledge with available evidence; a nominal approach was followed throughout with face-to-face conferences.

FINDINGS

The WG recommended a synonym set ("synset") ontological approach to the conceptualisation of this health condition underlying a clinical rationale for its diagnosis. It proposed replacing MR with Intellectual Developmental Disorders (IDD) in ICD-11, defined as "a group of developmental conditions characterized by a significant impairment of cognitive functions, which are associated with limitations of learning, adaptive behaviour and skills". The WG further advised that IDD be included under the parent category of neurodevelopmental disorders, that current distinctions (mild, moderate, severe and profound) be continued as severity qualifiers, and that problem behaviours removed from its core classification structure and instead described as associated features.

ORIGINALITY/VALUE

Within the ID/IDD synset two different names combine distinct aspects under a single construct that describes its clinical as well as social, educational and policy utilities. The single construct incorporates IDD as a clinical meta-syndrome, and ID as its functioning and disability counterpart. IDD and ID are not synonymous or mirror concepts as they have different scientific, social and policy applications. New diagnostic criteria for IDD should be based on a developmental approach, which accounts for the complex causal factors known to impact the acquisition of specific cognitive abilities and adaptive behaviours. The paper focuses on a new clinical framework for the diagnosis of IDD that also includes and complements the existing social, educational and policy components inherent in ID.

Diagnosing dementia in adults with Down's syndrome

Individuals with Down's syndrome (DS) are living longer and many will survive into their fifth or sixth decade of life. Among the DS population, the prevalence of dementia in Alzheimer's disease increases from 9.4% in age group 30-39 years to 54.5% age group 60-69 years. The psychopathology of dementia in Alzheimer's disease is similar to that seen in the general population although differences are apparent due to the underlying intellectual disability in DS and on the reliance on collateral information from informants. The diagnostic workup follows accepted practice although neuropsychological tests and neuroimaging will only be adjuncts to the clinical assessment; such investigations have limited diagnostic value. Presently, research is focused on identifying genetic and biological measures of Alzheimer's disease in DS.

Pharmacological management of behavioral and psychiatric symptoms in older adults with intellectual disability

Given medical and social advances, the life expectancy of individuals with intellectual disability (ID) has increased dramatically, leading to a generation of older individuals with such disabilities. This review focuses on the pharmacological treatment of behavioral and psychiatric symptoms and disorders in older adults with ID. Older adults with ID often present with medical co-morbidities and mental health issues. Medication management of behavioral and psychiatric problems is complicated by a higher risk for adverse events, lack of decision-making capacity, and complex care networks. Some studies have shown that individuals with ID and co-morbid mental disorders are undertreated in comparison with those with similar disorders in the general population, resulting in poorer outcomes. However, older adults with ID are also at risk of polypharmacy, and older age is a risk factor for development of side effects. A general principle is that medication treatment for psychiatric disorders in older individuals with ID should be started at low dosages and increased cautiously while monitoring response and side effects. The use of psychotropic drugs for older individuals with ID and behavioral problems remains controversial, particularly in those with dementia.

Mental illness, challenging behaviour, and psychotropic drug prescribing in people with intellectual disability: UK population based cohort study

OBJECTIVES

To describe the incidence of recorded mental illness and challenging behaviour in people with intellectual disability in UK primary care and to explore the prescription of psychotropic drugs in this group.

DESIGN

Cohort study.

SETTING

571 general practices contributing data to The Health Improvement Network clinical database.

PARTICIPANTS

33,016 adults (58% male) with intellectual disability who contributed 211,793 person years' data.

MAIN OUTCOME MEASURES

Existing and new records of mental illness, challenging behaviour, and psychotropic drug prescription.

RESULTS

21% (7065) of the cohort had a record of mental illness at study entry, 25% (8300) had a record of challenging behaviour, and 49% (16,242) had a record of prescription of psychotropic drugs. During follow-up, the rate of new cases of mental illness in people without a history at cohort entry was 262 (95% confidence interval 254 to 271) per 10,000 person years and the rate of challenging behaviour was 239 (231 to 247) per 10,000 person years. The rate of new psychotropic drug prescription in those without a previous history of psychotropic drug treatment was 518 (503 to 533) per 10,000 person years. Rates of new recording of severe mental illness declined by 5% (95% confidence interval 3% to 7%) per year (P<0.001), and new prescriptions of antipsychotics declined by 4% (3% to 5%) per year P<0.001) between 1999 and 2013. New prescriptions of mood stabilisers also decreased significantly. The rate of new antipsychotic prescribing was significantly higher in people with challenging behaviour (incidence rate ratio 2.08, 95% confidence interval 1.90 to 2.27; P<0.001), autism (1.79, 1.56 to 2.04; P<0.001), and dementia (1.42, 1.12 to 1.81; P<0.003) and in those of older age, after control for other sociodemographic factors and comorbidity.

CONCLUSIONS

The proportion of people with intellectual disability who have been treated with psychotropic drugs far exceeds the proportion with recorded mental illness. Antipsychotics are often prescribed to people without recorded severe mental illness but who have a record of challenging behaviour. The findings suggest that changes are needed in the prescribing of psychotropics for people with intellectual disability. More evidence is needed of the efficacy and safety of psychotropic drugs in this group, particularly when they are used for challenging behaviour.

Dementia diagnostic criteria in Down syndrome

OBJECTIVE

Dementia is a common clinical presentation among older adults with Down syndrome. The presentation of dementia in Down syndrome differs compared with typical Alzheimer's disease. The performance of manualised dementia criteria in the International Classification of Diseases (ICD)-10 and Diagnostic and Statistical Manual of Mental Disorders-IV-Text Revision (DSM-IV-TR) is uncertain in this population.We aimed to determine the concurrent validity and reliability of clinicians' diagnoses of dementia against ICD-10 and DSM-IV-TR diagnoses. Validity of clinical diagnoses were also explored by establishing the stability of diagnoses over time.

METHODS

We used clinical data from memory assessments of 85 people with Down syndrome, of whom 64 (75.3%) had a diagnosis of dementia. The cases of dementia were presented to expert raters who rated the case as dementia or no dementia using ICD-10 and DSM-IV-TR criteria and their own clinical judgement.

RESULTS

We found that clinician's judgement corresponded best with clinically diagnosed cases of dementia, identifying 84.4% cases of clinically diagnosed dementia at the time of diagnosis. ICD-10 criteria identified 70.3% cases, and DSM-IV-TR criteria identified 56.3% cases at the time of clinically diagnosed dementia. Over time, the proportion of cases meeting ICD-10 or DSM-IV-TR diagnoses increased, suggesting that experienced clinicians used their clinical knowledge of dementia presentation in Down syndrome to diagnose the disorder at an earlier stage than would have been possible had they relied on the classic description contained in the diagnostic systems.

CONCLUSIONS

Clinical diagnosis of dementia in Down syndrome is valid and reliable and can be used as the standard against which new criteria such as the DSM-5 are measured.

Validation of the Chinese version of the dementia screening questionnaire for individuals with intellectual disabilities (DSQIID-CV)

BACKGROUND

An increasing number of people with intellectual disabilities (ID) are at risk of developing age-related disorders such as dementia because of a dramatic increase in life expectancy in this population in the recent years. There is no validated dementia screening instrument for Chinese people with ID. The Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) was reported to be a valid, user-friendly, easy-to-use observer-rated instrument. It was developed in the UK and has good psychometric properties. Validation of a Chinese version of the DSQIID will facilitate its application among the Chinese population.

METHOD

The DSQIID was translated into the Chinese version (DSQIID-CV). By purposive sampling, service users with ID aged 40 years or over were recruited through two large centres serving adults with ID in Hong Kong. Carers who had taken care of the participants continuously for the past 6 months were invited to complete the DSQIID-CV. All participants were examined by qualified psychiatrists to determine the presence or absence of dementia.

RESULTS

Two hundred people with ID whose age ranged between 40 and 73 years (mean 51 years, SD=7.34 years) were recruited to the study. A clinical diagnosis of dementia was established in 13 participants. An overall total score of 22 as a screening cut-off provided the optimum levels of specificity (0.995) and sensitivity (0.923). The DSQIID-CV showed good internal consistency (alpha=0.945) for all its 53 items, and excellent test-retest reliability (0.978, n=46) and inter-rater reliability (1.000, n=47). Exploratory factor analysis resulted in a four-factor solution explaining 45% of the total variance.

CONCLUSIONS

The DSQIID-CV is shown to have robust psychometric properties. It is the first valid and reliable dementia screening instrument for Chinese adults with ID.

Ambulatory mental health data demonstrates the high needs of people with an intellectual disability: results from the New South Wales intellectual disability and mental health data linkage project

OBJECTIVE

To investigate the ambulatory mental health service profile of persons with intellectual disability (ID) in a representative sample of New South Wales (NSW).

METHODS

A statistical linkage key was used to link the Disability Services Minimum Data Set (DS-MDS) and a community mental health services dataset (MH-COM) for a representative area of NSW for the period 2005-2010. Linkage was undertaken in four NSW local health districts (LHDs), covering 36.7% of the NSW population. The mental health profiles and service use characteristics of people with an ID were compared to mental health service users without an ID.

RESULTS

Of the 89,262 people in the MH-COM over this 6-year period, 1,459 people (1.6 %) were identified as having an ID. Compared to those without an ID, people with an ID were more likely to have psychotic disorders, developmental disorders and personality disorders, and more than twice as likely to have an 'unknown' diagnosis. Compared to those without an ID, people with an ID were less likely to have depressive disorders, adjustment disorders and other disorders. Service use profiles revealed that people with an ID had 1.6 times more face-to-face contacts, and a total face-to-face contact time which was 2.5 times longer than people without an ID.

CONCLUSIONS

Ambulatory mental health data from NSW indicates that people with an ID receive care for a distinct range of mental disorders, and experience uncertainty regarding their diagnosis. People with an ID have higher service needs which require recognition and the allocation of specific resources. Such data provide a suitable baseline for future evaluation of the impact of ambulatory mental health reforms for people with an ID.

Down syndrome and dementia: Is depression a confounder for accurate diagnosis and treatment?

The past century has seen a dramatic improvement in the life expectancy of people with Down syndrome. However, research has shown that individuals with Down syndrome now have an increased likelihood of early onset dementia. They are more likely than their mainstream peers to experience other significant co-morbidities including mental health issues such as depression. This case study reports a phenomenon in which three individuals with Down syndrome and dementia are described as experiencing a rebound in their functioning after a clear and sustained period of decline. It is hypothesized that this phenomenon is not actually a reversal of the expected dementia trajectory but is an undiagnosed depression exaggerating the true level of functional decline associated with the dementia. The proactive identification and treatment of depressive symptoms may therefore increase the quality of life of some people with Down syndrome and dementia.