Identifying and assessing dementia in adults with learning disabilities
Dementia in people with learning disabilities can often be missed or overlooked
The life expectancy of people with learning disabilities, and particularly people with Down’s syndrome, has increased substantially over the past 80 years. In the 1930s the average life expectancy for people with Down’s syndrome was 9.9 years for males and 12 years for females (British Psychological Society, 2015).
Data from NHS Digital (2019) showed that the average life expectancy of people with learning disabilities in general is now 65 for women and 66 for men. This increased life expectancy has brought with it a significant increase in people with learning disabilities developing dementia. At present we do not know why this is the case, and more research is needed. Genetic factors may be involved, or a particular type of brain damage associated with a learning disability could be a cause.
It is, however, known why so many adults with Down’s syndrome have an increased risk of developing Alzheimer’s disease, as Down’s syndrome is a genetic disorder caused in 96% of cases by an extra copy of chromosome 21 and the gene for family history of Alzheimer’s is also on chromosome 21.
Signs and symptoms
Recognising the early signs of dementia in people with learning disabilities can be difficult and it is important for practitioners to recognise the possibility of diagnostic overshadowing – where the person’s difficulties are seen as part of their learning disabilities, rather than as the development of a separate need, such as dementia. The early signs of dementia can also be subtle and not happen every day and so can easily be missed.
People with more severe learning disabilities are often less likely to be concerned themselves that they may be developing dementia. This is because they may have less insight into the fact that they are experiencing problems. For people with mild learning disabilities, they may recognise that they are experiencing changes, but have difficulty in expressing it. In addition, support staff and families who closely support the person may not recognise subtle changes, whereas as someone who sees the person more infrequently a practitioner may be the first to notice any changes and can then raise these concerns with support staff and family.
Dementia may be very difficult to spot in people with profound and multiple disabilities because of their pre-existing limited functional abilities. If there has been no early diagnosis, practitioners will need to think about the late stage signs that may indicate the presence of dementia. These can include changes in the person’s ability to eat and drink, changes in day/night routine and/or changes in recognition.
Dementia in people with Down’s syndrome may also present atypically to those in the general population (who typically present with memory lapses) with changes in behaviour and/or personality that can precede the full clinical picture of dementia by some years. This may include changes to their mood, social skills and functions such as planning, problem solving and reasoning.
Assessment and diagnosis
Each local authority area has its own pathway for diagnosing dementia in adults with learning disabilities. This is often through the community learning disability team but may also be through mainstream dementia services. Practitioners should find out how the assessment pathway operates in their area and find out who needs to make the referral.
A key question that needs to be answered through the assessment is whether the person is experiencing changes in their cognitive and adaptive functioning. If so, practitioners need to examine what might be causing these changes and whether they can be remedied. There are many conditions that can mimic the early signs of dementia in people with learning disabilities and these need to be excluded as part of the assessment process before a diagnosis can be made.
It is important for practitioners to be able to recognise the signs, (as signs of dementia can be harder to spot in people with learning disabilities, especially if their disability is more severe) work with other professionals to rule out anything else that may be causing the changes in functioning and support the person to get an accurate and timely diagnosis. Diagnostic overshadowing should also be taken into account to ensure that the signs of dementia are not overlooked: it is important for the practitioner to consider the wide variety of possible physical, social and emotional explanations.
Good dementia care requires ongoing monitoring and review to ensure that support is appropriate to the person’s changing needs and practitioners should schedule regular reviews to monitor all aspects of care. The person should be supported to live as full a life as possible, with quality of life being the central focus and the practitioner will be crucial to enabling the person and their family and/or support staff to achieve this throughout the course of the dementia.