Who wouldn't want know whether they have a greater likelihood of getting Alzheimer's? While doctors don't have a crystal ball, they do have a small arsenal of tests that can determine risk, and some clinical trials are showing great promise.
"Until recently, we haven't been able to determine if someone had Alzheimer's disease until an autopsy was performed," explains David Morgan, M.D., CEO of the Byrd Alzheimer's Institute at the University of South Florida. "Clinicians are about 80% accurate (in determining whether someone has AD), but a lot of cases aren't black and white."
When Alzheimer's starts to take hold, the hippocampus is one of the first areas of the brain to be damaged. Proteins called amyloids start to take hold of that area of the brain, and then others, slowing killing off the nerve cells and robbing people of their ability to remember events and perform regular functions. There are tests, including physical and diagnostic, neurological, mental status, genetic testing and brain imaging that can now assist doctors in making a diagnosis.
So when should you or a love one seek medical attention to determine whether you have Alzheimer's?
"When anything happens that makes someone raise their eyebrow, it should raise a red flag," states Amanda Smith, M.D., Medical Director of the Byrd Alzheimer's Institute. For instance, if someone you love never forgets an appointment, but begins missing several within a few weeks, it's time to make a doctor's appointment, explains Dr. Smith.
Here are some tests doctors use to try and diagnose Alzheimer's disease:
Cognitive Tests & MMSE
A family or primary care physician can perform a physical exam and use lab tests to rule out that a lack of vitamins, thyroid issues, diabetes, kidney disease or even drug interactions are causing dementia.
If the cause of memory loss still hasn't been determined, the doctor may request some cognitive tests to see if the patient is aware of their symptoms, if they can remember a short list of words and instructions, and other questions to determine their range of everyday mental skills – this is often called a Mini-Mental State Exam (MMSE). According to the Alzheimer's Association, the maximum MMSE score is 30. Lower scores suggest mild, moderate or severe dementia. These tests should be performed yearly, at minimum, in order to track the progression of dementia.
While cognitive tests are helpful, "we don't have instructions to detect the earliest stages (of Alzheimer's), says Dr. Morgan. "And the problem detecting earlier is that different people have different mental capacities." Plus, he adds, all of us – whether we have a diagnosis of Alzheimer's or not- have good and bad days.
Neuropsychological
During this kind of testing, a physician will look to see if other brain disorders may be causing the memory loss, such as brain tumors, an accumulation of fluid, a stroke or Parkinson's disease may be causing the impairment. A neurological exam may include brain imaging, as well as testing a patients reflexes, eye movement, speech and coordination.
"I think they are somewhat effective," Dr. Morgan says of neuropsychological exams, which can sometimes take as long as six hours. "But for the earliest stages, they aren't sensitive enough." He believes these exams are best for patients who are already showing symptoms of AD.
Genetic Testing
Researchers know that certain genes increase the risk of developing AD or developing one of the rare forms of AD, called autosomal dominant Alzheimer's disease (ADAD), which tends to run in families. With ADAD, symptoms often occur earlier in life, but this form of the disease accounts for less than five percent of all cases.
The gene called APOE-e4, poses the strongest risk of developing AD. A blood test is available to determine whether a person has this gene. However, having the gene does not mean you will develop AD, only that the person might have a greater risk. Knowing this could encourage lifestyle changes to slow down the onset of Alzheimer's, but genetic testing is highly controversial and it usually is not covered by insurance plans.
Blood testing is also available to determine the presence of ADAD, but it is often performed as part of clinical trials.
Brain Imaging
Brain imaging is perhaps the most significant testing currently available to help determine AD. Using a MRI or CT scan can rule out other conditions that have similar symptoms to Alzheimer's, and reveal tumors, evidence of stroke or fluid in the brain. For the average healthy person, neurons in the brain die as we get older, causing the organ to shrink about one percent each year. In a person with AD, that amount increases to three percent annually. Only through brain imaging can doctors see how the brain is shrinking over a period of time, and provide a look at the structure of the brain.
PET Scans
One thing CT and MRI scans cannot do is determine the function of the brain. For that, PET scans show the most promise in the fight against Alzheimer's because they provide a look at the chemistry and structure of the brain. A doctor can determine whether brain tissue is living or dead, and detect abnormalities in cellular activity, which can usually be seen before symptoms take place.
During a PET scan, a glucose-based solution is injected into the body. The 3-D images taken by the PET scan help physicians look at patterns of the brain which are not using the sugar as fuel.
Future Treatments
Another tell-tale determination of AD is when a protein called beta-amyloid builds up on cells and turns into plaque. Eventually, the plaque keeps brain cells from communicating with each other. This plaque spreads through the brain in a rather predictable pattern during the course of AD. In fact, several medications are being tested in an effort to block or at least slow down amyloid build-up.
"The key is to find out if the patient has amyloid before death," Dr. Morgan explains. While a patient is still alive, it is possible to perform a biopsy to see if the protein is present, but the procedure is very invasive. Same goes for a spinal tap. All of us have soluble amyloid in our spinal fluid, but in AD patients, this fluid builds up.
That's one of the reasons Dr. Morgan and Dr. Smith are most excited about the experimental amyloid PET scan which is undergoing clinical trials at USF and could be approved for use as early as June, 2012.
"The amyloid builds up (in the brain) at least 10 years before symptoms," Dr. Morgan states. "The PET scan can pick it up at least five years before symptoms. That's important."
Just like people take statins to lower their cholesterol, taking anti-amyloids may one day help ward off getting dementia.
Dr. Morgan believes that by 2020, new medications coming to the marketplace will be able to delay the onset of Alzheimer's substantially.
In the meantime, the best thing for people to do is embrace a healthy lifestyle to help push back AD by five years or more.
Dr. Smith suggests a brain-healthy diet that's low in saturated fat, includes fish at least twice a week and plenty of fruits and vegetables every day. Regular exercise is also important, as well as stimulating your mind though mental and social activities. Consider learning a foreign language; do a word search one day and a Sudoku puzzle the next.
"All those things independently have significant scientific backing that they delay Alzheimer's disease," says Dr. Smith.