The Link Between Dementia and Down Syndrome

The Link Between Dementia and Down Syndrome

Imagine what it would be like to start to losing the mosaic of memories that makes you who you are.  Imagine what it would be like to wake up in the morning to find out that familiarity escapes your mind’s grasp.  To look at the faces of your family members and loved ones and find nothing- not a spark of intimacy, not an inkling of that warm feeling in your heart that once was tied to memories of your moments with them.  Nothing.

Imagine not being able to remember the way to the restroom in the morning.  What would it be like to suddenly forget which toothbrush is yours? What would it be like to not remember the taste of your favorite meal or forgetting whether or not you’ve eaten that day? Imagine not being able to do the things you have always loved to do, whether it be swimming, photography, art, or something as simple as going up the stairs of your Aunt’s house.  Imagine getting lost on the way home after you go out on a walk, stranded and alone, not knowing your name or who you are. Those with Down Syndrome have a much higher chance to undergo these experiences in their lifetime. The average prevalence rate of Alzheimer’s dementia in people with Down Syndrome is around 15% that increases with age with signs of Alzheimer’s dementia showing over the age of 35 compared to the average early onset of Alzheimer’s dementia at the age of 40 or 50 (Mayo Clinic, 2018; Nieuwenhuis-Mark, 2009).

Research has found that those with Down Syndrome develop Alzheimer’s disease at an average age younger than the mean age for the general population. In a 20-year longitudinal study done by researchers McCarron and Colleagues, following 77 people with Down Syndrome 35 years and older from 1996 to 2015, it was found that 97.4% of those participants developed dementia at a mean age of 55 years old (McCarron et. al., 2017). The manifestation of psychological changes typical of Alzheimer’s disease occur in nearly all persons with Down Syndrome over the 40 years old (Tyler and Shank, 1996).

The symptoms of Alzheimer’s disease are often debilitating and its consequences can be devastating. Researchers William and Lai followed 96 persons with Down Syndrome and non-treatable dementia for 8 years and found that there are three phases of clinical deterioration in these patients. During the initial phases, individuals with high functioning Down Syndrome spoke less, had trouble with their memory, and had feelings of temporarily traveling through time.  Individuals with low functioning Down Syndrome showed: “apathy, inattention, and decreased social interactions” (Tyler and Shank, 1996). During the second phase of dementia, it was noted that those with Down Syndrome had a decline in daily activity performance, deteriorating work performance, and a shuffling gait (Tyler and Shank, 1996). During the second phase, 84% of persons with Down Syndrome also experience tonic-clonic seizures, which cause body stiffness and convulsions.  During the final phase of dementia, those with Down Syndrome stopped walking and lost voluntary control over their urination and defecation, and they passed away typically within 3 to 5 years of the onset of their dementia (Tyler and Shank, 1996). This is quicker than individuals without Down Syndrome, who have later ages of dementia onset and slower rates of deterioration (Tyler and Shank, 1996).

The importance of research is tantamount in the fields of medicine and psychology to diagnose, understand, and eventually treat such cases.  However, Down Syndrome is the least funded, yet most frequently occurring, chromosomal disorder by the National Institute of Health (Facts and FAQ, 2018). In 2010, Down Syndrome Research Funding took up only 0.0009% of the total NIH Budget of $30,860 million (Research for People, 2018).  It is astounding how little is paid to research for such a prevalent genetic disorder.

However, there is hope.  More research has been done on the association between dementia and Down Syndrome as well as the diagnoses and interventions.  There are now interventions to increase an individual with Down Syndrome’s quality of life and maximize their strengths to help them adjust to their changing abilities and needs and live more comfortably by reducing behavioral disturbances (Nieuwenhuis-Mark, 2009).  As quoted by Niewenhuis-Mark in their article, “the development of dementia of Alzheimer type is frequent but not inevitable, and some people with DS reach old age without clinical features of dementia” (Nieuwenhuis-Mark, 2009).  

Not everyone with Down Syndrome will develop Alzheimer’s dementia in old age, therefore research, understanding, and diagnosis is extremely crucial and time sensitive.  


Facts and FAQ About Down Syndrome. (2018, August 17). Retrieved from

Mayo Clinic. (2018). Early-onset Alzheimer’s: When symptoms begin before age 65. [online] Available at:  [Accessed 22 Sep. 2018].

McCarron, M. m., McCallion, P., Reilly, E., Dunne, P., Carroll, R., & Mulryan, N. (2017). A prospective 20-year longitudinal follow-up of dementia in persons with Down syndrome. Journal Of Intellectual Disability Research, 61(9), 843-852. doi:10.1111/jir.12390

Research for People with Down Syndrome: National Institutes of Health Funding. (2018, March 28). Retrieved from

Nieuwenhuis-Mark, R. E. (2009). Diagnosing Alzheimer’s dementia in Down syndrome: Problems and possible solutions. Research in Developmental Disabilities,30(5), 827-838. doi:

Tyler, C. V., Jr., & Shank, J. C. (1996, June). Dementia and Down syndrome. Journal of Family Practice, 42(6), 619+. Retrieved from

Leave a Reply

Your email address will not be published. Required fields are marked *

[ Back To Top ]