Assessing Dementia in People with IDD
Prevalence and incidence of Dementia in those with Intellectual/Developmental Disabilities (IDD)
- People with (IDD) are at higher risk of dementia than the general population.
- Down syndrome carries a higher risk of Dementia, and specifically Alzheimer’s disease, with younger onset.
- Dementia in people with IDD from other causes is less researched. Prevalence studies show conflicting results. However, research indicates that the onset of Dementia in people with non-DS ID is on average 10 years earlier than in the general population.
Risk factors for dementia in people with IDD
- Specific risk factors for Dementia in people with IDD include Down syndrome, poor physical and mental health, including undiagnosed health problems, and sensory impairments.
- Risk factors for Dementia in the general population are also relevant to people with IDD: poor diet and exercise, cardiovascular risk factors, poor engagement in education, social activities, and employment, head injury, and genetic factors such as APOE genotype.
Presentation of Dementia in people with IDD
- The full range of Dementias may appear in people with IDD, including mixed presentations. A sizable group of people with IDD with suspected declines meet some, but not all, criteria for Dementia.
- At least in people with Down syndrome, behavioral and personality changes and declines in executive function may appear before memory deficits.
Assessment of Dementia in people with IDD
- There is no gold-standard diagnostic test for Dementia in people with IDD. Assessment tools useful for the general population are not appropriate for this group. Diagnosing Dementia in people with IDD requires demonstrating a decline from baseline in cognition and functioning, across at least three longitudinal assessments.
- The earliest signs of Dementia can be easily overlooked or misattributed by care providers.
- Primary care providers should screen for Dementia in people with IDD. When this should occur depends on whether the person has Down syndrome.
- Comprehensive cognitive assessments should be conducted for those at high risk of Dementia. This includes people with Down syndrome, and those with non-Down syndrome IDD who show signs of slowing or declines.
For additional information, support and/or guidance, please consult directly with your Care Manager.