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

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.

Does Employment Complexity Promote Healthy Cognitive Aging in Down Syndrome?

Adults with Down syndrome (DS) experience high risk for Alzheimer's disease (AD), but there is variability in the timing of transition from a cognitively stable state to prodromal AD and dementia. The present study examined the association between a modifiable lifestyle factor, employment complexity, and cognitive decline across two time points in adults with DS. Employment complexity, defined as the degree of problem-solving or critical thinking required for employment activities, was operationalized using the Dictionary of Occupational Titles, a system which classifies occupations based on three categories: Data, People, and Things. Eighty-seven adults with DS (M = 36.28 years, SD = 6.90 years) were included in analyses. Partial correlations revealed that lower employment complexity involving People and Things were associated with increased dementia symptoms. Lower employment complexity involving Things was also associated with memory decline. These findings have implications for vocational programs focused on job training and placement for adults with DS.

The Global Deterioration Scale for Down Syndrome Population (GDS-DS): A Rating Scale to Assess the Progression of Alzheimer's Disease

The aim of this study is to adapt and validate the global deterioration scale (GDS) for the systematic tracking of Alzheimer's disease (AD) progression in a population with Down syndrome (DS). A retrospective dual-center cohort study was conducted with 83 participants with DS (46.65 ± 5.08 years) who formed the primary diagnosis (PD) group: cognitive stability (n = 48), mild cognitive impairment (n = 24), and Alzheimer's disease (n = 11). The proposed scale for adults with DS (GDS-DS) comprises six stages, from cognitive and/or behavioral stability to advanced AD. Two neuropsychologists placed the participants of the PD group in each stage of the GDS-DS according to cognitive, behavioral and daily living skills data. Inter-rater reliability in staging with the GDS-DS was excellent (ICC = 0.86; CI: 0.80-0.93), and the agreement with the diagnosis categories of the PD group ranged from substantial to excellent with κ values of 0.82 (95% CI: 0.73-0.92) and 0.85 (95% CI: 0.72, 0.99). Performance with regard to the CAMCOG-DS total score and orientation subtest of the Barcelona test for intellectual disability showed a slight progressive decline across all the GDS-DS stages. The GDS-DS scale is a sensitive tool for staging the progression of AD in the DS population, with special relevance in daily clinical practice.

Dementia in People with Severe/Profound Intellectual (and Multiple) Disabilities: Practice-Based Observations of Symptoms

INTRODUCTION

Observable dementia symptoms are hardly studied in people with severe/profound intellectual (and multiple) disabilities (SPI(M)D). Insight in symptomatology is needed for timely signaling/diagnosis. This study aimed to identify practice-based observations of dementia symptoms in this population.

METHODS

Care professionals and family members were invited to complete a survey about symptoms. Quantitatively analyzed survey data were further deepened through semi-structured interviews with care professionals having vast experience in signaling/diagnosing dementia in this population. Symptoms were categorized using a symptom matrix.

RESULTS

Survey respondents and interviewees frequently observed a decline in activities of daily living (ADL) functioning and behavioral and psychological changes, like increased irritability, anxiety, apathy and decreased eating/drinking behavior. Cognitive symptoms were particularly recognized in persons with verbal communication and/or walking skills. To lesser extent motor changes and medical comorbidities were reported.

CONCLUSION

Increased insight in dementia symptoms contributes to developing a dedicated screening instrument for dementia in people with SPI(M)D.

Dementia in people with severe or profound intellectual (and multiple) disabilities: Focus group research into relevance, symptoms and training needs

BACKGROUND

Differentiating dementia from baseline level of functioning is difficult among people with severe/profound intellectual (and multiple) disabilities. Moreover, studies on observable dementia symptoms are scarce. This study examined (a) the relevance of dementia diagnosis, (b) observable symptoms and (c) training/information needs.

METHODS

Four explorative focus groups were held with care professionals and family members who have experience with people with severe/profound intellectual (and multiple) disabilities (≥40 years) and decline/dementia.

RESULTS

Thematic analysis showed that participants wanted to know about a dementia diagnosis for a better understanding and to be able to make informed choices (question 1). Using a categorisation matrix, cognitive and behavioural changes were shown to be most prominent (question 2). Participants indicated that they needed enhanced training, more knowledge development and translation, and supportive organisational choices/policies (question 3).

CONCLUSIONS

Timely identifying/diagnosing dementia allows for a timely response to changing needs. This requires a better understanding of symptoms.

Physical activity and cognitive and imaging biomarkers of Alzheimer's disease in down syndrome

Adults with Down syndrome (DS) are at risk for Alzheimer's disease. Despite sharing trisomy 21, however, there is variability in the age of disease onset. This variability may mean that other factors, such as lifestyle, influence cognitive aging and disease timing. The present study assessed the association between everyday life physical activity using an actigraph accelerometer and cognitive functioning and early Alzheimer's disease pathology via positron emission tomography amyloid-β and tau and diffusion tension imaging measures of white matter integrity in 61 non-demented adults with DS. Percent time in sedentary behavior and in moderate-to-vigorous activity were associated (negatively and positively, respectively) with cognitive functioning (r = -.472 to .572, p < 0.05). Neither sedentary behavior nor moderate-to-vigorous activity were associated with amyloid-β or tau, but both were associated with white matter integrity in the superior and inferior longitudinal fasciculus (Fractional Anisotropy: r = -.397 to -.419, p < 0.05; Mean Diffusivity: r = .400, p < 0.05). Longitudinal studies are needed to determine if physical activity promotes healthy aging in DS.

The neglected puzzle of dementia in people with severe/profound intellectual disabilities: A systematic literature review of observable symptoms

BACKGROUND

Dementia is increasingly prevalent in people with severe/profound intellectual disabilities. However, early detection and diagnosis of dementia is complex in this population. This study aimed to identify observable dementia symptoms in adults with severe/profound intellectual disabilities in available literature.

METHOD

A systematic literature search was conducted in PubMed, PsycINFO and Web of Science with an exhaustive search string using a combination of search terms for severe/profound intellectual disabilities and dementia/ageing.

RESULTS

Eleven studies met inclusion criteria. Cognitive decline, behavioural and psychological alterations, decline in activities of daily living as well as neurological and physical changes were found.

CONCLUSIONS

Only a very limited number of studies reported symptoms ascribed to dementia in adults with severe/profound intellectual disabilities. Given the complexity of signalling and diagnosing dementia, dedicated studies are required to unravel the natural history of dementia in this population.

Assessment of dementia in a clinical sample of persons with intellectual disability

BACKGROUND

Assessment of age-associated disorders has become increasingly important.

METHODS

In a clinical setting, people with intellectual disability with and without dementia were assessed retrospectively using the Neuropsychological Test Battery (NTB) and the Dementia Questionnaire for People with Learning Disabilities (DLD) at two different times to analyse neuropsychological changes and diagnostic validity. One group (n = 44) was assessed with both instruments, while the DLD was applied in 71 patients.

RESULTS

In the NTB (n = 44), only patients with dementia (n = 26) showed a decline in the NTB total score and three subscales. Receiver operating characteristic analysis revealed a diagnostic sensitivity of .67, a specificity of .81, and an area under the curve (AUC) of .767. In the DLD group (n = 71), only those with dementia displayed a decrease in the cognitive and social scale; diagnostic sensitivity and specificity values were low (.61/.63) and the AUC was .704.

CONCLUSIONS

Neuropsychological assessment was sensitive to detect cognitive changes over time. Sensitivity values of both instruments suggest a reassessment at a later time point.

Informant-based assessment instruments for dementia and their measurement properties in persons with intellectual disability: systematic review protocol

INTRODUCTION

Persons with intellectual disability (ID) are at a higher risk of developing dementia than persons without ID, with an expected earlier onset. Assessment methods for the general population cannot be applied for persons with ID due to their pre-existing intellectual and functional impairments. As there is no agreed-upon measure to assess dementia in persons with ID, multiple instruments for this purpose have been developed and adapted in the past decades. This review aimed to identify all available informant-based instruments for the assessment of dementia in persons with ID, to evaluate and compare them according to their measurement properties, and to provide a recommendation for the most suitable instruments. Additionally, an overview of the amount and quality of research on these instruments will be provided.

METHODS AND ANALYSIS

This review will be conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We will adhere to the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines and use a set of characteristics developed for assessment instruments for persons with ID, the Characteristics of Assessment Instruments for Psychiatric Disorders in Persons with Intellectual Developmental Disorders. Two comprehensive, systematic literature searches will be applied in 10 international databases, including ASSIA, CINAHL, Cochrane Library, ERIC, MEDLINE, PsycINFO, Scopus, Web of Science, OpenGrey and ProQuest Dissertations and Theses Global. Risk of bias and quality assessment will be done according to COSMIN guidelines. We will apply the modified Grading of Recommendations, Assessment, Development and Evaluation approach to rate the overall quality of the available evidence.

ETHICS AND DISSEMINATION

No ethics statement is needed for this study. The results will be submitted to a peer-reviewed journal and will be presented at international conferences.

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.

Screening for Cognitive Impairment in Geriatrics

There are many instruments for screening cognitive impairment. The common tools for screening cognitive impairment are categorized into 4 groups (very brief, brief, self-administered, and test batteries) in geriatrics. There are some tests used for specific tests of 6 cognitive domains (learning and memory, language, executive function, complex attention, and social cognition) by following the DSM-V criteria. Different settings, stages, conditions, and specific people need some specific tools for screening cognitive impairment. It must be noted that there is some harm in screening for cognitive impairment in geriatrics.

Plasma neurofilament light chain: A potential prognostic biomarker of dementia in adult Down syndrome patients

People with Down syndrome (DS) are at high risk of developing Alzheimer disease (AD) with aging. The diagnosis and treatment trials are hampered by a lack of reliable blood biomarkers. Plasma neurofilament light chain (NfL) is one of the established biomarkers of AD, suggesting that it may be useful as an indicator of dementia in DS patients. The aims of this study were: 1) to examine whether plasma levels of NfL in DS patients are correlated with decreased adaptive behavior scores one year after sample collection, and 2) to compare plasma levels of NfL in adults with DS and an age-matched healthy control population. In this study, plasma levels of NfL in 24 patients with DS and 24 control participants were measured by the single-molecule immunoarray (Simoa) method. We observed significantly increased plasma NfL levels in the DS compared with the control group. There was a significant correlation between age and levels of plasma NfL in both groups. This age-dependent elevation was steeper in the DS compared with the control group. Moreover, elevated plasma NfL was associated with decreased adaptive behavior scores one year later, after age-adjustment. Previously reported blood-based biomarkers available in Simoa for DS, plasma total tau and phosphorylated tau, were not significantly correlated with the annual decrement of adaptive behavior scores after age-adjustment. These results suggest that plasma NfL has the potential to serve as an objective biomarker to predict dementia in adult DS patients.

Signs in People with Intellectual Disabilities: Interviews with Managers and Staff on the Identification Process of Dementia

The life expectancy of people with intellectual disabilities (ID) has steadily increased, which has been accompanied by an increased risk of dementia. Staff and managers are key resources for safety diagnosis since they deliver information about people with ID behavior every day. The aim of the present study was to explore the identification process employed by staff and managers to detect signs of suspected dementia in people with an ID within intellectual disability services (ID-services). Twenty managers and 24 staff within an ID-service were interviewed and qualitative latent content analysis was applied. A model consisting of three themes on three levels of resources for the identification process of signs of suspected dementia emerged from the analysis. On the first level was the time and continuity in the care relationship, which is crucial for identifying and responding to changes in cognitive ability that indicate dementia. On the second level, the staff identify deficiencies in their own knowledge, seek support from colleagues and managers within their workplace and, on the third level, outside their workplace. Staff and managers expressed a need for early and continuous guidance and education from specialists in dementia and primary healthcare. This finding indicates an urgent need for intervention research and digital support for staff in dementia care.