Understanding & Diagnosing Alzheimer’s Disease

The most common type of dementia, Alzheimer’s is an irreversible disease that progressively destroys memory, thinking skills, and eventually the ability to carry out even basic tasks. In people with Alzheimer’s disease, brain cells begin to break down and eventually die, resulting in a steady decline in the patient’s memory and overall mental function. It can be a devastating diagnosis with a powerful impact not only on the patient, but on those closest to them.

What Exactly Is Alzheimer’s?

A patient with Alzheimer’s experiences loss of the connections between neurons, or nerve cells, in the brain. Neurons are required to transmit messages between the many different parts of the brain, as well as from the brain to a person’s muscles and organs. The loss of these neuron connections plays a major role in the degenerative nature of Alzheimer’s. When doctors look at the brain tissue of someone with Alzheimer’s under a microscope, two characteristic types of abnormalities can be seen.

  1. Plaques. Clumps of a protein called beta-amyloid are present. This protein breaks down and destroys brain cells in a number of ways, including interfering with communication between the brain cells. While the actual cause of brain-cell death in Alzheimer’s is still unclear, the collection of beta-amyloid plaques on the outside of the brain is believed to be responsible.
  2. Tangles. The cells of the brain require a specialized support and transport system that carries nutrients and essential materials along their many extensions. This crucial system needs the normal functioning and structure of a specific protein, tau. In patients with Alzheimer’s, there are threads of this tau protein twisted into abnormal tangles within brain cells, which causes the failure of this essential transport system. This failure is another factor thought to play a role in the deterioration and death of the brain cells.

The damage to the brain of someone with Alzheimer’s occurs first in the hippocampus, which is the area of the brain essential for forming memories. As the patient’s neurons die, more and more parts of the brain begin to be affected. By the late stages of Alzheimer’s, the brain damage is widespread, and the overall amount of brain tissue has withered significantly. Unfortunately, Alzheimer’s disease can only be truly diagnosed after death, when microscopic examination of the brain reveals theses characteristic plaques and tangles.

How is Alzheimer’s Diagnosed?

Unfortunately, there is no actual test to confirm Alzheimer’s disease in a patient who is still living. While it’s fairly easy to diagnose dementia, it is far more difficult to determine whether the dementia is actually caused by Alzheimer’s disease. Instead, a doctor will diagnose Alzheimer’s as the most likely cause of the patient’s symptoms based on a number of tests.

Doctors use the following tests to help distinguish Alzheimer’s disease from other causes of dementia.

  1. Physical and neurological exams. A doctor will perform a physical examination to check overall neurological health by testing:
  • Sight
  • Hearing
  • Balance
  • Reflexes
  • Muscle tone
  • Muscle strength
  • Coordination
  • Ability to walk
  • Ability to get out of a chair
  1. Lab tests. Doctor’s generally perform a number of blood tests to rule out other possible causes of symptoms such as memory loss and confusion. These tests usually include those for thyroid disorders and vitamin deficiencies.
  2. Mental status testing. Most doctors will conduct a short mental status test to assess memory and thinking skills. In addition, they may send a patient for more extensive neuropsychological testing to learn more about overall mental function compared with others at a similar age with a similar level of education.
  3. Brain imaging. Images of the brain can be used to find visible abnormalities related to other conditions including trauma, strokes, and tumors that can cause cognitive impairment. Newer imaging applications may eventually make it possible for doctors to detect the specific brain changes caused by Alzheimer’s disease. Current brain-imaging technologies include:

Magnetic resonance imaging (MRI). Using radio waves and a strong magnetic field to produce detailed images of the brain, MRIs can rule out other conditions that may cause or complicate cognitive symptoms. They can also be used to evaluate whether shrinkage in brain regions associated with Alzheimer’s disease has occurred.

Computerized tomography (CT). CT scans produce cross-sectional images, or image slices, of the brain. CT’s are primarily used to rule out strokes, tumors, and trauma.

Positron emission tomography (PET). A PET uses a low-level radioactive tracer that has been injected in a vein to take pictures of the overall activity in various regions of the brain. This can be used to identify exactly which part(s) of the brain aren’t functioning properly. Newer PET techniques are also able to detect brain levels of amyloid plaques and tau tangles, the two specific abnormalities of Alzheimer’s.

  1. Cerebrospinal fluid testing. In some situation, such as a rapidly progressive dementia or early-onset dementia, cerebrospinal fluid may be tested for biomarkers that indicate the likelihood of Alzheimer’s disease.

Luckily, today there is a great awareness and understanding of Alzheimer’s, and there are many support programs and services for those dealing with the disease. If you are interested in learning about caregiver support services or in-home care for a loved one with Alzheimer’s, Specialty Care Services would be happy to help!

2017-12-30T15:47:44+00:00