Imaging links structural brain changes and cognitive decline in Parkinson's

December 7, 2016
Affected structural connections in patients with PD and MCI relative to healthy control subjects and patients with Parkinson disease (PD) without mild cognitive impairment (MCI). The principal connected component is shown in red, and the other affected connections not included in the principal connected component are shown in green. Subnetworks show altered structural connectivity (decreased fractional anisotropy or increased mean diffusivity) in patients with PD and MCI relative to healthy control subjects at P < .01 Credit: Radiological Society of North America

People with Parkinson's disease and cognitive impairment have disruptions in their brain networks that can be seen on a type of MRI, according to a study appearing online in the journal Radiology.

Parkinson's disease (PD) is a progressive disorder of the central nervous system characterized by tremors or trembling and stiffness in the limbs, impaired balance and coordination. It affects about 10 million people worldwide. As PD progresses, many patients develop (MCI), a decline in cognitive abilities, including thinking, memory and language. MCI can be identified in approximately 25 percent of newly diagnosed PD patients, and patients with MCI progress to dementia more frequently than those with normal cognitive performance.

For the new study, lead investigator Massimo Filippi, M.D., from the Neuroimaging Research Unit at San Raffaele Scientific Institute in Milan, Italy, coauthors Federica Agosta, M.D., Ph.D., and Sebastiano Galantucci, M.D., and other colleagues used an MRI technique called diffusion tractography to look for differences in the neural networks of PD patients with and without MCI.

Increasingly, the is understood as an integrated network, or connectome, that has both a structural and functional component. By applying an analytical tool called graph analysis to the imaging results, researchers can measure the relationships among highly connected and complex data like the network of connections in the human brain.

"Cognitive impairment in PD is one of the major non-motor complications of the disease, as well as one of the major concerns of patients and caregivers at the time of diagnosis," Dr. Agosta said. "Study of the changes related to cognitive impairment in PD is imperative in order to be able to answer patients' questions and finally be able to predict the future development of this condition."

MR images show microstructural white matter damage (tract-based spatial statistics). Areas of decreased fractional anisotropy (FA) (red) and increased mean diffusivity (blue) overlapped on the overall FA skeleton (green) in groups of patients with Parkinson disease compared with healthy control subjects (P < .05 corrected for multiple comparisons). Credit: Radiological Society of North America

The study group was made up of 170 PD patients, including 54 with MCI and 116 without, and 41 healthy controls. Analysis of imaging results showed that only PD patients with MCI had significant alterations at the brain network level. Measurements of the movement and diffusion of water in the brain, an indicator of the condition of the brain's signal-carrying white matter, differentiated PD patients with MCI from healthy controls and non-MCI PD patients with a good accuracy. Researchers said the results show that cognitive impairment in PD is likely the consequence of a disruption of complex structural rather than degeneration of individual white matter bundles.

The results may offer markers to differentiate PD patients with and without cognitive deficits, according to Dr. Agosta.

"If confirmed and replicated by other studies, these results would suggest the use of MRI in PD to support the clinicians in monitoring the disease and predicting the occurrence of cognitive complications," she said.

The researchers have obtained resting state functional MRI data from the patients and plan to study the functional connectome alterations associated with in PD and how structural and functional abnormalities are interrelated.

The study is part of an international collaboration between the San Raffaele Scientific Institute and the Clinic of Neurology at the University of Belgrade in Belgrade, Serbia, led by Vladimir Kostic, M.D.

Explore further: Imaging test may identify biomarker of Alzheimer's disease

Related Stories

Imaging test may identify biomarker of Alzheimer's disease

May 27, 2015
Degeneration of the white matter of the brain may be an early marker of specific types of Alzheimer's disease (AD), including early-onset AD, according to results of a new study published in the journal Radiology.

'Traffic jam' in brain linked to common cognitive disorder

September 6, 2016
Brain MRI could help improve the diagnosis of people with a common type of cognitive disorder, according to a new study published online in the journal Radiology.

Widespread brain atrophy detected in Parkinson's disease with newly developed structural pattern

December 12, 2011
Atrophy in the hippocampus, the region of the brain known for memory formation and storage, is evident in Parkinson's disease (PD) patients with cognitive impairment, including early decline known as mild cognitive impairment ...

A step forward searching for an early biomarker of Alzheimer's disease

July 19, 2016
Researchers from Centre for Biomedical Technology (CTB) at Universidad Politécnica de Madrid (UPM) have shown that the abnormal pattern of functional connectivity in patients with mild cognitive impairment can be considered ...

Finding a treatment for Parkinson's disease dementia

September 2, 2015
University of Adelaide neuroscientists are leading a world-first study into a form of dementia experienced by many Parkinson's disease suffers, which is expected to ultimately lead to a new therapy for the condition.

Trial helps doctors tell Lewy body dementia from Alzheimer's, Parkinson's

September 21, 2016
Knowing that many clinicians find it difficult to correctly diagnose patients with Lewy body dementia, researchers at The Ohio State University Wexner Medical Center set out to develop a clinical profile for these patients. ...

Recommended for you

How a seahorse-shaped brain structure may help us recognize others

December 8, 2017
How do we recognize others? How do we know friend from foe, threat from reward? How does the brain compute the multitude of cues telling us that Susan is not Erica even though they look alike? The complexity of social interactions—human ...

Brain networks that help babies learn to walk ID'd

December 8, 2017
Scientists have identified brain networks involved in a baby's learning to walk—a discovery that eventually may help predict whether infants are at risk for autism.

Why we can't always stop what we've started

December 7, 2017
When we try to stop a body movement at the last second, perhaps to keep ourselves from stepping on what we just realized was ice, we can't always do it—and Johns Hopkins University neuroscientists have figured out why.

Mutations in neurons accumulate as we age: The process may explain normal cognitive decline and neurodegeneration

December 7, 2017
Scientists have wondered whether somatic (non-inherited) mutations play a role in aging and brain degeneration, but until recently there was no good technology to test this idea. A study published online today in Science, ...

How we learn: Mastering the features around you rather than learning about individual objects

December 7, 2017
A Dartmouth-led study on how we learn finds that humans tend to rely on learning about the features of an object, rather than on the individual object itself.

Researchers launch atlas of developing human brain

December 7, 2017
The human brain has been called the most complex object in the cosmos, with 86 billion intricately interconnected neurons and an equivalent number of supportive glial cells. One of science's greatest mysteries is how an organ ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.