Blood Could Hold Key to Diagnosing Early-Stage AD
Recent research suggests a new lab test can help to diagnose Alzheimer’s Disease quickly and easily. This test was confirmed in two studies in which the researchers found a specific protein whose presence increased as the disease progressed.
Alzheimer’s disease also referred to as AD, is a form of dementia and is sometimes called Alzheimer’s dementia. In the US AD is the 6th leading cause of death, affecting one in 10 Americans who are 65 years of age and older. The estimated number of Americans with AD last year was 5.8 million, 80 percent of whom are over the age or 75.
How Alzheimer’s Disease is Diagnosed
AD is diagnosed by testing the person’s memory and problem-solving abilities to assess the patient’s cognitive decline. Family members are usually included in discussions regarding their loved one’s ability to safely perform basic tasks and adequately take care of themselves. Brain scans (MRI, CT, PET) are often used to look for visible degenerative changes in the brain. Sometimes spinal fluid obtained via ‘spinal tap’ is analyzed for signs of AD. These tests take time to conclude, are often pricey and make enrollment in clinical trials for AD difficult.
Blood tests are currently only used to measure thyroid and B12 levels as vitamin B12 deficiency and thyroid disorders can resemble the symptoms of AD.
New Blood Test
Two studies last year, one in California of 404 people and the other in Swed en involving 1131 people showed similar results. These studies were looking for an important protein gone bad — tau. Good tau maintains the stability of the connectors between the cells. These connectors move important molecules from one cell to the next. The researchers were looking, specifically speaking, pTau 181.
And they found it.
The amount of plasma pTau 181 increased from a normal level to a higher level in people who were developing AD, but had no clear symptoms, to an even higher amount in people who had been diagnosed with AD. This elevated blood test only specifically indicated AD; and was not found in people with other neurological disorders such as Parkinson’s disease.
The data suggest that plasma pTau181 could be useful as a screening tool to identify AD in individuals who are at risk for cognitive decline or who already have cognitive impairment. This could be very helpful because AD could be identified and its symptoms treated before the early signs start. For people who already have cognitive decline this test would clearly show if the decline is due to AD. This blood test is relatively cheap and easy to perform, allowing patients to avoid brain scans and the spinal tap.
While research into AD treatments continues, the current medications can only temporarily improve difficulties related to thinking, reasoning and memory loss.
These medications support brain chemicals which carry information from brain cell to brain cell. But they are unable to stop the decline and death of brain cells that allow AD to progress.
Medications for mild to moderate AD
AD patients, and their caregivers, deal with behavioral and mental issues, including:
Cholinesterase inhibitors are medications prescribed for mild to moderate AD. They may help reduce some symptoms and help control some behavioral symptoms. These medications are: Razadyne (galantamine), Exelon (rivastigmine), and Aricept (donepezil).
These treatments are designed to prevent the breakdown of acetylcholine, a brain chemical believed to be important for memory and thinking. Cholinesterase inhibitors may become less effective because the brain makes less acetylcholine as AD progresses.
These three drugs work much the same way, so switching from one to another probably will not produce a significant difference. But a patient just might respond better to one AD drug than another.
Medications for moderate to severe AD
Namenda (memantine), is used to treat patients with moderate to severe Alzheimer’s disease. It decreases symptoms so some people can take care of themselves better. Extending the time they can use the bathroom independently is one benefit.
Other FDA approved medications for moderate to severe AD include: donepezil, the rivastigmine patch, and Namzaric, a combination of memantine and donepezil.
Memantine is believed to work by regulating a brain chemical called glutamate. Too much glutamate may lead to brain cell death. Because memantine works differently from cholinesterase inhibitors, the two types of drugs can be prescribed in combination.
Yvonne Stolworthy MSN, RN has spent many years in critical care and as an educator in a variety of settings, including clinical trials. Currently she is applying her nursing knowledge to healthcare journalism.