Alzheimer’s disease is a progressive neurological condition. It is a type of dementia (more information about dementia is available on the National Institute on Aging website). Alzheimer’s disease is characterized by microscopic changes in the brain that are described as plaques (clumps of a protein called beta-amyloid) and tangles (twisted strands of a protein called tau).
There is not one specific test that definitively diagnoses Alzheimer’s disease. Researchers continue to work on developing diagnostic tools. Some of the efforts include developing tests of blood or spinal fluid samples that measure levels of beta-amyloid or other biomarkers of Alzheimer’s disease. In addition, brain scans called positron emission tomography (PET) scans are being used to detect plaques. These tests are primarily used in research settings.
Outside of research settings, a diagnosis of Alzheimer’s disease is made by assessing for and finding a pattern of decline that is consistent with Alzheimer’s disease and ruling out other possible causes of a decline.
A pattern of decline consistent with Alzheimer’s disease may include:
- Memory deterioration
- Loss of previously mastered skills
- Unsteady gait
- Dysphagia (difficulty swallowing)
- Weight loss
- Psychological changes
Healthcare providers assess for this pattern through conversations with individuals with Down syndrome and their caregivers. The GLOBAL Medical Care Guidelines for Adults with Down Syndrome recommend assessing adults with Down syndrome and interviewing their primary caregivers about changes from their typical function annually beginning at age 40. The National Task Group on Intellectual Disabilities and Dementia Practices Early Detection Screen for Dementia (NTG-EDSD) can be used by healthcare providers and caregivers to aid in the assessment and interview processes.
Neuropsychological testing is typically part of the evaluation for Alzheimer’s disease for people who do not have an intellectual disability. This testing may include questions and tasks to assess memory and cognition. It is usually more difficult in people with Down syndrome and other intellectual disabilities. There are a few tests that are more specific for people with Down syndrome, such as the Down Syndrome Mental Status Examination and the Dementia Scale for Down Syndrome. These tests seem to be most beneficial when done sequentially over time. Clinically, we find that, by the time a cognitive decline is evident on the testing, the decline and diagnosis are often clear from the person’s symptoms.
If there is a pattern of decline, it is important to rule out other factors that may be causing or contributing to the decline. Many of the other causes have treatments that can improve or eliminate symptoms. They include (but are not limited to):
- Depression and other psychological concerns
- Sleep apnea
- Thyroid disease
- Vitamin B-12 deficiency
- Metabolic diseases such as kidney disease, diabetes, or calcium abnormalities
- Celiac disease
- Loss of hearing or vision
- Atlantoaxial instability or other cervical (neck) problems
- Heart disease
- Seizure disorder
- Normal pressure hydrocephalus
- Medication side effect
The Alzheimer's Association website has more information about diagnosing Alzheimer's disease.
Our Resource Library has additional articles and webinars about Alzheimer’s disease in people with Down syndrome in the Alzheimer's Disease and Dementia section.