Particularly in the early stages of dementia and Alzheimer’s disease, the symptoms are very subtle, making diagnosis difficult. Indeed, the only truly definitive diagnosis of Alzheimer’s disease can be done through an autopsy performed after death, according to the U.S. National Institutes of Health.
An autopsy would confirm the presence of tangles of nerve fibers (called neurofibrillary tangles) and plaques in the brain tissues. But in order to be of help, doctors have to determine the possible presence of Alzheimer’s disease while the patient is still alive.
Doctors have a number of tools to help them eliminate other possibilities and come up with a “probable Alzheimer’s disease,” often shortened to PRAD. The diagnosis of Alzheimer’s is usually done at specialized centers.
The diagnostic process
A useful first step in the process is for the patient’s doctor to interview the patient and the family members about the individual’s general health, medical history, and the patient’s current capability to perform customary daily routines.
The doctor will be alert for signs of the onset of dementia. The condition may be indicated by excessively repetitive narrations or questions, lack of interest in activities and favorite hobbies, self-neglect, increasing frequency of accidents, memory lapses, loss of ability to handle money, loss of visuospatial ability (e.g. getting lost in familiar places), changes in behavior and personality, and other subtle hints.
Once the doctor suspects Alzheimer’s disease, various tests will be administered. These are designed to confirm the three most common characteristics of Alzheimer’s: loss of ability to learn and remember information (or memory functions), visual and spatial difficulties, and impairment of language capabilities (self-expression and word-finding problems). There will be neuro-psychological tests of memory, simple problem solving, language skills, calculations and counting problems, and attention.
In addition, there will be the medical tests to get a gauge of the current physical state of the patient. These usually include testing blood, urine and spinal fluids. In certain situations, the doctor may order one or more brain scans (MRI, PET, CT) to screen for strokes or tumors in the brain, which adversely affect memory ability.
It is possible for the test results to reveal other causes leading to the symptoms experienced by the patients. There are several health conditions with symptoms that mimic those of Alzheimer’s disease, especially damage to the memory functions.
These include brain tumors, diseased vascular vessels feeding blood to the brain, reactions to medications and drugs, vitamin deficiency, depression, and thyroid problems. Unlike the irreversible Alzheimer’s disease, some of these health problems successfully respond to treatment.
Diagnosis for vascular dementia, the second most common cause of dementia, is generally based on radiological and clinical evidence of vascular disease in the brain’s blood vessels.