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Ultrasound Test May Predict Parkinsonís Risk
- Jul 19 2011
Using a non-invasive imaging test, researchers found that the risk of developing Parkinson’s disease (PD) was 17 times higher among people with a detectable pattern in the brain area called the substantia nigra. The study appears in the July 2011 issue of Archives of Neurology.
The test, called transcranial sonography, helps clinicians assess the area of the brain that is affected by Parkinson’s – the substantia nigra – using non-invasive imaging (ultrasound). Earlier studies have shown that in people with Parkinson’s, the substantia nigra “lights up” on an image more than in healthy individuals.
The study authors, from three research centers in Germany and Austria, wanted to find out whether the test might detect changes in the brain before Parkinson’s motor symptoms develop. Led by Daniela Berg, M.D., at the Hertie Institute for Clinical Brain Research in Tübingen, Germany, they screened more than 1,800 healthy volunteers over the age of 50 with transcranial sonography. Study participants also had a medical exam and neurological assessment. Half were men. About three years after their first scan, 1535 participants underwent a follow-up test.
- At the time of their follow-up tests, 11 study participants out of 1,535 had been diagnosed with Parkinson’s.
- 262 study participants (18.7 percent) had substantia nigra “light up” on their first scan or in medical terms, showed increased substantia nigra hyperechogenicity.
- Eight of the 262 with abnormal scans later developed Parkinson’s.
- Two participants with normal scans did develop Parkinson’s.
- Individuals with abnormal transcranial sonography scans were about 17 times more likely to have developed Parkinson’s three years later than people with a initial normal scan.
What Does it Mean?
This study is the first to show a highly increased risk of Parkinson’s among older individuals with specific ultrasound findings from transcranial sonography. The test has the advantages of being non-invasive, inexpensive and easy to perform. However, the test had a few major limitations; first only eight people had an initial positive test, and second, the vast majority of those with positive test results (254 of 262) did not proceed to develop Parkinson’s in follow up. Therefore, it would be very hard to interpret either positive or negative ultrasound test results.
An important goal of Parkinson’s research is to develop neuroprotective drugs —medications that can slow or prevent onset of the disease. People who are at high risk of developing Parkinson’s will benefit from such therapies, so it also is important to be able to conduct studies similar to this one, which focus on identifying populations at risk. Further research is required in order to assess whether this test may be useful when used in conjunction with other means of predicting Parkinson’s risk.
Reference: Daniela Berg et al. Enlarged Substantia Nigra Hyperechogenicity and Risk for Parkinson Disease: A 37-Month 3-Center Study of 1847 Older Persons.
Arch Neurol. 2011;68(7):932-937.
Source Date: Jul 19 2011