Adults with Down syndrome are at increased risk of Alzheimer's disease as they grow older, but Alzheimer's disease is not inevitable. There are many other possible issues to consider when concerns about memory arise, so a thoughtful approach is very important.
The Connection Between Alzheimer’s Disease and Down Syndrome
Down syndrome occurs when an individual has a full or partial third copy of chromosome 21. (Typically, people have two copies of each chromosome.) Chromosome 21 plays a key role in the relationship between Down syndrome and Alzheimer’s disease as it carries a gene that produces one of the key proteins involved with changes in the brain caused by Alzheimer’s. Additionally, scientists have located several genes on chromosome 21 that are involved in the aging process and that contribute to the increased risk of Alzheimer’s disease. It is this unique property of chromosome 21 that makes the disease a more acute concern for people with Down syndrome than those with other forms of intellectual disability.
General Definition and Overview
Alzheimer’s disease is a type of dementia that gradually destroys brain cells, affecting a person’s memory and their ability to learn, make judgments, communicate and carry out basic daily activities. Alzheimer’s disease is characterized by a gradual decline that generally progresses through three stages: early, middle and late stage disease. These three stages are distinguished by their general features, which tend to progress gradually throughout the course of the disease. Alzheimer’s disease is not inevitable in people with Down syndrome. While all people with Down syndrome are at risk, many adults with Down syndrome will not manifest the changes of Alzheimer’s disease in their lifetime. Although risk increases with each decade of life, at no point does it come close to reaching 100%. This is why it is especially important to be careful and thoughtful about assigning this diagnosis before looking at all other possible causes for why changes are taking place with aging. Estimates show that Alzheimer’s disease affects about 30% of people with Down syndrome in their 50s. By their 60s, this number comes closer to 50%.
The Span of Alzheimer’s Disease
Alzheimer's disease is a progressive disease, gradually and steadily moving from early, to middle, to late stage. As the disease progresses, it is expected that abilities and skills decrease and the need for support and supervision increases, so aim to prepare proactively for each step.
- Short term memory loss (difficulty recalling recent events, learning and remembering names and keeping track of the day or date; asking repeated questions or telling the same story repeatedly)
- Difficulty learning and retrieving new information
- Expressive language changes (word finding difficulties, smaller vocabulary, shorter phrases, less spontaneous speech)
- Receptive language changes (difficulty understanding language and verbal instructions)
- Worsened ability to plan and sequence familiar tasks
- Behavior changes
- Personality changes
- Spatial disorientation (difficulty navigating familiar areas)
- Worsened fine motor control
- Decline in work productivity
- Difficulty doing complex tasks requiring multiple steps (including household chores and other daily activities)
- Depressed mood
- Decreased ability performing everyday tasks and self-care skills
- Worsened short-term memory with generally preserved long-term memory
- Increased disorientation to time and place
- Worsened ability to express and understand language (vocabulary shrinks even further, communicates in short phrases or single words)
- Difficulty recognizing familiar people and objects
- Poor judgment and worsened attention to personal safety
- Mood and behavior fluctuations (anxiety, paranoia, hallucinations, restlessness, agitation, wandering)
- Physical changes related to progression of the disease including: new onset seizures, urinary incontinence and possible fecal incontinence, swallowing dysfunction, mobility changes (difficulty with walking and poor depth perception)
- Significant memory impairment (loss of short term and long term memory, loss of recognition of family members and familiar faces)
- Dependency on others for all personal care tasks (bathing, dressing, toileting, and eventually, eating)
- Increased immobility with eventual dependence on a wheelchair or bed
- Profound loss of speech (minimal words or sounds)
- Loss of mechanics of chewing and swallowing, leading to aspiration events and pneumonias
- Full incontinence (both urinary and fecal)
Recognizing Alzheimer’s Disease
ESTABLISHING A “BASELINE”
Most adults with Down syndrome will not self-report concerns about memory. Instead, it will take an astute caregiver who knows the individual well to identify early changes or concerns and bring them to the attention of a medical professional. Alzheimer’s disease is suspected when there is a change or a series of changes seen in an individual as compared to their previous level of functioning. Thus, in order to observe change effectively, one must be informed about what the individual was capable of doing at his or her very best. This could be considered the individual’s “baseline.”
The primary importance of having a good description and understanding of an individual’s baseline is so it can be used as a basis of comparison if changes are observed as the individual grows older. It is extremely helpful to record baseline information throughout adulthood – noting basic self-care skills, personal achievements, academic and employment milestones, talents, skills and hobbies. A baseline can also be established formally at an office visit with a memory specialist, where these components can be reviewed and memory abilities can be tested.
Formal screening for memory concerns should be a priority throughout mid-to later-adulthood. Alzheimer’s disease is a clinical diagnosis. That means that it requires a doctor to make the diagnosis based on his or her judgment. There is no single blood test, x-ray or scan that will make or confirm the diagnosis. The diagnosis depends largely on an accurate history detailing progressive loss of memory and daily functioning. It is vitally important that a history be provided by someone (a family member, a longtime caregiver, etc.) who knows the person well. It is important to seek the opinion of a specialist who will take all factors into account to arrive on a diagnosis thoughtfully. It is worth the effort to not rush the diagnosis. Make sure that the assessment has been thorough andthat all other possibilities were given careful consideration. Note that many of the common conditions related to aging and Down syndrome outlined in the beginning of this article can be mistaken as dementia if not identified properly (hearing loss, low thyroid function, vision loss, pain, sleep apnea, etc.). If the individual is showing change compared to their baseline memory or functioning, it is important to consult with the primary care doctor to assess for the presence of these other potentially treatable or correctable conditions.
SEEKING A MEMORY EVALUATION
Look for a memory specialist (a geriatrician, neurologist, psychiatrist or neuropsychologist). Ideally, the specialist would have experience assessing individuals with intellectual disabilities. Assessments should be comprehensive and adapted appropriately for each patient’s baseline intellectual disability. A thorough assessment should take into account all other potential contributing factors (medical, psychiatric, environmental, social) that could also account for, or contribute to, the reported changes.
AFTER THE DIAGNOSIS IS MADE
First, make sure that the diagnosis seems accurate. Was it arrived upon in a thoughtful and thorough manner, carefully excluding other possible causes that may explain the changes that were observed and reported?
Next, be proactive in building a support network. The key feature of Alzheimer’s disease is that it is a progressive disorder, meaning it is expected that the individual’s needs are going to increase over time. The support network encompasses the primary care doctor, memory specialist and other related medical specialists, caregivers, day program or workshop staff, state or agency support staff, other family, friends, etc.
LEARN ABOUT DEMENTIA
This article aims to provide a basic introduction to this topic, but one should seek out other resources to learn more and to get support. Some resources are provided at the end of this page.
- Alzheimer’s Association (National Office)
800-272-3900 (24-hour hotline)
Offers information and resources on Alzheimer’s disease
- Alzheimer’s Disease International
Provides a fact sheet on dementia and intellectual disabilities
- Alzheimer's Foundation of America
Serves families and caregivers of individuals affected by Alzheimer's by providing services including a helpline and online guides for caregivers
- NTG Early Detection Screen for Dementia
Can be used by family members and caretakers to evaluate changes in an individual's cognitive functioning
- Understanding Dementia and Memory Loss
Contains an excellent guide for caretakers of individuals with Down syndrome and Alzheimer's disease by Alzheimer's Australia (see pdf file under "related information")
- Adults with Down Syndrome. Pueschel, S. M. Baltimore, MD: Brookes Publishing. (2006)
- Alzheimer’s Disease and Dementia in Down Syndrome and Intellectual Disabilities. Prasher, V. P. Radcliffe Publishing. (2005)
- Dementia, Aging, and Intellectual Disabilities: A Handbook. Janicki, M. Dalton, A.J.P. Brunner/Mazel Publisher. Now Routledge Mental Health. (1999)
- The Dementias: Hope Through Research. The National Institute of Neurological Disorders and Stroke and the National Institute on Aging. (2013) Can be found at www.ninds.nih.gov/disorders/dementias/the-dementias.pdf.
- Down Syndrome and Dementia. Holland, A. In Dementia. London, UK: Oxford University Press. (2000)
- Mental Wellness in Adults with Down Syndrome. McGuire, D. and Chicoine, B. Bethesda, MD: Woodbine House. (2005)