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Persons with Intellectual Disability (PWIDs) face unique challenges, particularly as they age and become susceptible to health conditions like dementia, which complicates their care.
This article sheds light on the important connection between dementia and intellectual disability, offering insight into risk factors, signs and symptoms, and the challenges of diagnosis. It also provides practical strategies and valuable support for caregivers. By raising awareness and sharing helpful information, this article aims to ensure that persons with intellectual disability and dementia receive the compassionate care they deserve, while maintaining their dignity and independence.
Dementia and Intellectual Disability
What are dementia and intellectual disability?
Dementia refers to a group of symptoms that impact the brain, causing a gradual decline in cognitive functions, including memory, learning, orientation, language, comprehension, and judgment.1 Similarly, someone who is diagnosed with intellectual disability will experience limitations in their cognitive functioning and independent living skills. According to the Diagnostic and Statistical Manual of Mental Disorders, intellectual disability is a neurodevelopmental disorder that presents as a generalised delay or impairment in the development of intellectual functioning and adaptive abilities, such as independence in daily living, before the age of 18.2
The symptoms of dementia can sometimes be mistaken for the effects of intellectual disability, and the support needed may be different from what is typically provided to older adults. Understanding the complexities of both conditions is crucial for ensuring appropriate care, improving quality of life, and addressing the needs of this often-overlooked group.
Prevalence and Risk Factors
In an article published by the Institute of Mental Health in 2024, 1 in 33 people aged 60 to 74 in Singapore are estimated to have dementia.3 As compared to the general population, the likelihood for PWIDs (without additional mental health diagnosis) to develop dementia does not differ drastically.4 Additionally, a study conducted in 2023 showed that 2 in 25 PWIDs (without Down syndrome) aged 60 to 69 have dementia, and 5 in 25 PWIDs (without Down syndrome) aged 70 to 79 have dementia.5 However, it is important to note that this has only been established for PWIDs without any other conditions, such as Down Syndrome or Autism Spectrum Disorder.
The known risk factors for dementia in PWIDs are similar to those in the neurotypical population. They include increased age, hypertension, depression, stroke 5,and polypharmacy10 , among others. However, being diagnosed with Down syndrome or Autism spectrum disorder poses additional risk factors.
Studies have found that persons with Down syndrome have a higher likelihood of developing dementia, starting around age 407 , and adults with Down syndrome show a significantly elevated risk for Alzheimer’s disease.8 Down syndrome is a genetic condition in which a person has an extra copy of chromosome 21.6 The extra copy of chromosome 21 in the body’s cells affects how the body develops and functions.6 It is estimated that after the age of 60, about 50–70% of adults with Down syndrome will be affected by dementia, as they experience physical and cognitive changes about 20 years earlier than the general population.9,11
Whereas adults with Autism spectrum disorder under the age of 65 are approximately 2.6 times more likely to be diagnosed with dementia compared to the general population, due to limited such as reduced access to higher education, and fewer community engagements for social and recreational activities.12
Signs and Symptoms of Dementia in PWIDs
According to the National Task Group on Intellectual Disabilities and Dementia Practices13, PWIDs who may have dementia will experience increasing challenges with staying focused, finding their way in familiar environments, remembering names of people, visual and motor coordination, and impeded sleep quality. They may also exhibit changes in their daily routine, sleeping or eating habits, and require more assistance in managing self-care tasks. Difficulties in emotional regulation could also manifest in aggressive behaviours and unfounded fears. The signs mentioned above are typically observed as a cluster of behaviours.9
Getting a Diagnosis of Dementia for a PWID
In Singapore, healthcare professionals who typically diagnose patients with dementia are neurologists, geriatricians, and geriatric psychiatrists. The diagnostic or assessment tools that are used for the general population are often inappropriate for PWIDs, since this group of people, due to their limited cognitive functioning, are likely to perform poorly on cognitive tests, even if they do not have dementia. Therefore, diagnosing dementia in PWIDs requires showing a decline from their usual cognitive and functional levels.14 However, many PWIDs may not have undergone a baseline assessment prior to noticeable declines.
Numerous medical conditions can exhibit symptoms similar to dementia, and PWIDs tend to have a higher prevalence of existing physical health issues compared to the general population. A significant number of health and sensory impairments remain undiagnosed in people with ID.15 Therefore, it is crucial to rule out other treatable medical conditions prior to confirming a dementia diagnosis.
Diagnosing dementia in a PWID can be challenging, as assessing cognitive changes often relies heavily on caregivers to signal observable dementia symptoms. The symptoms of dementia and intellectual disability often overlap, making it important to establish a baseline of a person’s behaviour and cognitive abilities to track any changes over time. To support this, the National Task Group has developed the Early Detection Screen for Dementia (EDSD), which can be completed by anyone who has known the PWID for a significant number of years.
Early detection and diagnosis of dementia enable caregivers and healthcare professionals to make informed decisions about adjusting care, support, and treatment. It is recommended for caregivers to visit a polyclinic to get a referral to a specialist should the PWID displays group of behaviours, as mentioned in the section on the signs and symptoms of dementia in PWIDs, that deviates from their baseline.
Dementia-friendly Approach
Caring for someone with dementia can be challenging, and having an intellectual disability adds complexity to caregiving, as PWIDs will have even lower self-care skills, communication abilities, and cognitive functioning. Positive interactions are crucial for PWIDs, even as their ability to engage effectively with loved ones diminishes. When communication becomes more difficult or needs go unmet, it can lead to changes in mood and behaviour, which can cause stress for caregivers and disrupt daily routines.16,17
A dementia-friendly approach includes five strategies that facilitate effective two-way communication, helping to reduce frustration and stress for both parties. These strategies can significantly enhance the caregiving experience by fostering better understanding and connection, ultimately improving the quality of care for PWIDs with dementia.
While persons living with dementia may face difficulties in carrying out daily tasks like showering or dressing, encouraging them to use their existing skills and abilities can help maintain their independence. Caregivers can achieve this by being flexible in how they provide support and guidance for daily tasks. For example, by creating a supportive environment for PWIDs to participate in activities without feeling overwhelmed17, and breaking tasks into smaller steps while providing prompts appropriately.
Persons living with dementia may experience a reality that differs from others, such as recalling past events or believing they still have certain abilities. Validation involves acknowledging their feelings and beliefs by expressing empathy for their believed challenges and acceptance of their reality.18 Positive validation of emotion and feeling may reduce agitation.19
Life story portfolios are created by gathering the lived experiences and core memories of PWIDs into a folder. This resource can help them recall past events and create opportunities for meaningful conversations. Studies around the typical population have shown that creating life stories improves communication and strengthens relationships between the individual and their carers. Life stories are also a key component of reminiscence therapy, which can help preserve memories and foster emotional connections.20
When a person with dementia is experiencing negative thoughts or feelings, redirection to a positive stimulus can help shift their focus to more pleasant memories. During difficult moments, it is important for caregivers to speak calmly and provide clear, step-by-step instructions to help the person navigate the situation and feel more at ease.9
Support for Families and Caregivers
Financial Support
Caregiving is a continuous learning journey. Caring for someone can feel challenging at first, but being prepared empowers you to provide the best for your loved one. Caregivers sometimes face financial distress due to depletion of financial assets as a result of caring for their loved ones with special needs and the rising cost of medical expenses to pay.21 There are several financial support schemes for caregivers in Singapore. Find out more about these options here.
Caregiver Support
Caregiver support refers to resources and assistance provided to individuals who are responsible for caring for someone with a chronic illness, disability, or ageing-related issues. This support can help alleviate emotional, physical, and financial challenges that caregivers often face.
Below are some common types of caregiver support, adapted from A Guide to Taking Care of Yourself.
Overall, caregiver support aims to improve the wellbeing of both caregivers and those they care for, helping caregivers manage their responsibilities and emotions effectively.
Conclusion
Caring for PWIDs who also live with dementia requires a deep understanding of both conditions and their complex interaction. As PWIDs age, they become increasingly vulnerable to health issues like dementia, which can complicate care and often go undiagnosed due to overlapping symptoms. Recognising these signs early is essential for providing timely, effective support.
Caregivers play a pivotal role in identifying cognitive and behavioural changes and must be equipped with the right tools and strategies to offer compassionate care. Dementia-friendly approaches—such as clear communication, validation, and life story portfolios—can improve the quality of life for PWIDs with dementia. Additionally, access to financial support and caregiver resources is critical to reduce emotional and financial burdens on families.
By fostering collaboration between healthcare providers, caregivers, and support networks, we can ensure that PWIDs with dementia receive the care and respect they deserve, safeguarding their dignity, independence, and overall wellbeing.
AUTHOR BIO
Movement for the Intellectually Disabled of Singapore (MINDS)
This article is contributed by the Dementia Workgroup at MINDS AHPHub: Sng Jing Ning, Senior Occupational Therapist; Nadia Lok Yi Zhen, Occupational Therapist; Wong Jie Qi, Occupational Therapist; Mofiana bte Md Salim, Social Work Associate; and Velmurugan Amirthambigai, Physiotherapist. Together, they leverage their expertise to address the challenges of dementia care.
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- Alzheimer’s Disease International (2009) World Alzheimer’s 568 Report: The Global Prevalence of Dementia. Available online: 569 http://www.alz.co.uk/research/world-report-2009
- American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). American Psychiatric Association.
- Institute of Mental Health. (2024). IMH study shows decrease in prevalence of dementia and improvement in treatment gap among older adults in Singapore over the past decade. Retrieved September 2, 2024, from https://www.imh.com.sg/Newsroom/News-Releases/Documents/WISE%202%20Press%20Release_28Aug_IMHFINAL.pdf
- Zigman, W.B., Schupf, N., Devenny, D., Miezejeski, C., Ryan, R., Urv, T.K., Schubert, R., & Silverman, W. (2004). Incidence and prevalence of dementia in elderly adults with mental retardation without Down syndrome. American Journal on Mental Retardation, 109, 126–141. doi:10.1352/0895-8017(2004)109.
- Takenoshita, S., Terada, S., Inoue, T., Kurozumi, T., Yamada, N., Kuwano, R., & Suemitsu, S. (2023). Prevalence and modifiable risk factors for dementia in persons with intellectual disabilities. Alzheimer’s Research & Therapy, 15(1), 125.
- S. Centers for Disease Control and Prevention. (2024). Down Syndrome. Retrieved October 10, 2024, from https://www.cdc.gov/birth-defects/about/down-syndrome.html#cdc_disease_basics_overview-what-it-is
- Bayen, E., Possin, K. L., Chen, Y., de Langavant, L. C., & Yaffe, K. (2018). Prevalence of aging, dementia, and multimorbidity in older adults with Down syndrome. JAMA neurology, 75(11), 1399-1406.
- Holland, A. J., & Oliver, C. (1995). Down’s syndrome and the links with Alzheimer’s disease. Journal of Neurology, Neurosurgery, and Psychiatry, 59, 111–114.
- National Task Group on Intellectual Disabilities and Dementia Practice. (2012). ‘My thinker’s not working’: A national strategy for enabling adults with intellectual disabilities affected by dementia to remain in their community and receive quality supports. Retrieved October 9, 2024, from aadmd.org/ntg/thinker
- Margolis, S. A., Kelly, D. A., Daiello, L. A., Davis, J., Tremont, G., Pillemer, S., Denby, C., & Ott, B. R. (2021). Anticholinergic/sedative drug burden and subjective cognitive decline in older adults at risk of Alzheimer’s disease. The Journals of Gerontology: Series A, 76(6), 1037–1043. https://doi.org/10.1093/gerona/glaa222
- Matthew P. Janicki & Arthur J. Dalton (2000) Prevalence of Dementia and Impact on Intellectual Disability Services. Mental Retardation: June 2000, Vol. 38, No. 3, pp. 276-288
- Vivanti, G., Tao, S., Lyall, K., Robins, D. L., & Shea, L. L. (2021). The prevalence and incidence of early‐onset dementia among adults with autism spectrum disorder. Autism Research, 14(10), 2189-2199.
- National Task Group on Intellectual Disabilities and Dementia Practices. (n.d.). Facts About Dementia. Retrieved September 10, 2024, from https://www.the-ntg.org/facts-about-dementia
- Torr, J. (2016). Dementias. In C. Hemmings & N. Bouras (Eds.), Psychiatric and Behavioral Disorders in Intellectual and Developmental Disabilities (pp. 55–64). chapter, Cambridge: Cambridge University Press.
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