Research shows that most people currently living with dementia have not received a formal diagnosis. In high income countries, only 20-50% of dementia cases are recognised and documented in primary care. This ‘treatment gap’ is certainly much greater in low and middle income countries, with one study in India suggesting 90% remain undiagnosed. If these statistics are extrapolated to other countries worldwide, it suggests that approximately three quarters of people with dementia have not received a diagnosis, and therefore do not have access to treatment, care and organised support that getting a formal diagnosis can provide.
Doctors may ask questions about health, conduct cognitive tests, and carry out standard medical tests to determine whether to diagnose a person with Alzheimer’s disease. If a doctor thinks a person may have Alzheimer’s, they may refer the person to a specialist, such as a neurologist, for further assessment. Specialists may conduct additional tests, such as brain scans or lab tests of spinal fluid, to help make a diagnosis. These tests measure signs of the disease, such as changes in brain size or levels of certain proteins.
How is Alzheimer’s disease diagnosed?
Doctors use several methods and tools to help determine whether a person who is having memory problems has Alzheimer’s disease.
To diagnose Alzheimer’s, doctors may:
Ask the person and a family member or friend questions about overall health, use of prescription and over-the-counter medicines, diet, past medical problems, ability to carry out daily activities, and changes in behavior and personality.
Conduct tests of memory, problem solving, attention, counting, and language.
Carry out standard medical tests, such as blood and urine tests, to identify other possible causes of the problem.
Perform brain scans, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET), to support an Alzheimer’s diagnosis or to rule out other possible causes for symptoms.
These tests may be repeated to give doctors information about how the person’s memory and other cognitive functions are changing over time.
People with memory and thinking concerns should talk to their doctor to find out whether their symptoms are due to Alzheimer’s or another cause, such as stroke, tumor, Parkinson’s disease, sleep disturbances, side effects of medication, an infection, or another type of dementia. Some of these conditions may be treatable and possibly reversible.
If the diagnosis is Alzheimer’s, beginning treatment as early as possible in the disease process could help preserve daily functioning for a while. An early diagnosis also helps families plan for the future. They can take care of financial and legal matters, address potential safety issues, learn about living arrangements, and develop support networks.
In addition, an early diagnosis provides people with more opportunities to participate in clinical trials or other research studies testing possible new treatments for Alzheimer’s.