The Connection Between Alzheimer’s Disease and Down syndrome

Individuals with Down syndrome are born with a partial or full copy of chromosome 21, within this same chromosome is the APP gene. The APP or Amyloid Precursor Protein gene, makes a protein and too much of this protein causes clumps (beta-amyloid plaques) in the brain. These plaques combined with another protein called tau tangles decrease brain function and are the trademarks of Alzheimer’s disease. Many people will develop these tangles and plaques as they age but will never develop Alzheimer’s disease. However estimates suggest that 25% of individuals with Down syndrome will show signs of Alzheimer’s disease or related dementia by the age of 50 and up to 75% will show signs by the age of 60 and over.

Alzheimer’s Disease Symptoms in Down syndrome

Although Alzheimer’s disease is associated mostly with memory loss it has many other effects to the brain. In individuals with Down syndrome changes in overall function, personality and behavior are more common initial symptoms. Other early symptoms seen with individuals with Down syndrome are:
  • Reduced interest in being social, conversing or expressing thoughts
  • Decreased enthusiasm for usual activities
  • Decline in ability to pay attention
  • Sadness, fearfulness or anxiety
  • Irritability, stubbornness, or aggression
  • Restlessness or sleep disturbances
  • Seizures that begin in adulthood 
  • Changes in coordination/walking
  • increased noisiness or excitability

Early Detection

Alzheimer’s is a progressive disease that gradually destroys brain cells. With this in mind, once you begin to see symptoms of dementia, it is probable that there has been protein buildup causing brain cell atrophy (shrinking) and cell death for 10 years already. This is why Early Detection is so important especially in people with Down syndrome because they are at risk almost 20 years before the general population. When dementia can be identified early, there is potential to proactively address signs and delay symptoms. Services and supports may be more effective if offered prior to significant thought and/or function change. Early assessments can help in identifying potentially treatable conditions that are causing symptoms. Early detection can lead to greater opportunities to impact quality of care and quality of life. Diagnosing dementia in individuals with Intellectual or Developmental Disabilities is more difficult than the general population due to certain barriers some of which include:

1. Inability to report– Individuals with I/DD may not be able to report signs and symptoms

2. Lack of assessment tools– Most generally used dementia assessment tools are not relevant for people with I/DD as the measures often test for skills or knowledge not often possessede by adults with I/DD. 

3. Measuring change– Difficulty measuring change from previous level of functioning. A baseline is needed to detect changes over time, the NTG-EDSD is the recommended assessment to determine a baseline.

4. Diagnostic overshadowing– Subtle changes may not be noticed or attributed to existing I/DD.

5. Lack of medical history– Due to staff turnover, family unavailable for information, health care provider turnover and many general practitioners aren’t trained to work with individuals with I/DD.

Establishing a Baseline

Alzheimer’s disease is suspected when a change in memory, personality or overall function occurs in a person from their previous level of functioning. In order to observe this change accurately one must be informed about the individuals capabilities at their very best functioning (baseline). We suggest using the NTG-EDSD or the NTG- Early Detection Screen for Dementia to properly assess for a baseline. To find the screen and more information about who can administer the screen click the picture below.