Friday, December 28, 2012

MRI – Diagnostic Tool for Alzheimer’s and FTLD

When a young person develops dementia, physicians have a difficult task of determining the underlying cause. If a familial disease exits, it is easier to look at a biomarker of that particular disease, but in many cases, there is no family history and the long, painstaking process of elimination begins.

When Jim developed dementia, our process to diagnosis was a complicated path with many twists and turns. One of the early tests was an MRI (magnetic resonance  imaging) which oddly enough was determined to be “normal.”

A year later, after an abnormal SPECT (single-photon emission computed tomography) scan, the neurologist ordered a second MRI. Unlike the MRI a year sooner, this one came back with a transcript that listed several abnormalities. It doesn’t seem to me that Jim’s brain would change that much in a year, so I often wondered if clues were missed in the first MRI. Perhaps they were looking for a brain tumor and didn’t see one, or could the person who read it not notice that he was looking at the brain of a forty-nine year old man?

Regardless of the issue, I was disappointed that the initial MRI didn’t show the changes in Jim’s brain a year sooner. It delayed our finding out that his forgetfulness and loss of skills was a brain disease and not some kind of mental issue.

An MRI is a valuable diagnostic tool when the information is carefully interpreted. A new study at Perelman School of Medicine at the University of Pennsylvania has shown a seventy-five percent accuracy differentiating between Alzheimer’s and FTLD (frontotemporal lobar degeneration). FTLD often affect younger people and is the most common form of dementia for people under age sixty-five.

Some of the methods previously used to accurately determine the difference between early onset Alzheimer’s and other types of dementia were more invasive—for example, a lumbar puncture. Often, the real cause was not known until autopsy, as in Jim’s case. After ten years of numerous tests, treatments, and five years in a nursing home, we finally learned that Jim’s Alzheimer’s type of dementia was specifically corticobasal degeneration. It was a disease I had never heard of and had not once been offered as the diagnosis.

I know the agony and frustration a family goes through while trying to uncover the underlying cause of a loved one’s dementia. Maybe in the big picture, it doesn’t always make a lot of difference in the treatment. It can make a difference in whether the side effects of some of the medication is worth the benefits especially if the drug therapy targets Alzheimer’s plaques, but no plaques exist with the disease your loved one has.

Also, you wonder at what point the tests become more expensive than they are worth. If an MRI can screen for Alzheimer’s and FTLD, a more expensive PET (positive emission tomography) or invasive lumbar puncture may not be necessary. Medication that helps with the symptoms of Alzheimer’s could be targeted to those that it helps rather than given to everyone with dementia symptoms.

The researchers who conducted this study used other methods to confirm the MRI results. Since the MRI could differentiate in seventy-five percent of the cases, only the remaining twenty-five percent who could not be determined would need further testing.

This is progress using a test that has been around since the early 1980s. The results of this new study increases the possibility that MRIs can be used to measure disease progression in clinical trials or to determine the effectiveness of drug therapies.

Personally, I’m for anything that helps families learn what type of dementia their loved one has and for diagnostic tools that can streamline clinical trials.

Copyright © December 2012 by L.S. Fisher