Summary: According to a new study, disruptions in brain networks can be seen with neuroimaging technology in people with MCI and Parkinson’s disease.
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 mild cognitive impairment (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 human brain 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.”
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 brain networks 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 cognitive impairment 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.
About this Parkinson’s disease research article
Funding: The work was funded by the Ministry of Education and Science, Republic of Serbia, Ministero della Salute.
Source: Linda Brooks – RSNA Image Source: NeuroscienceNews.com image is credited to RSNA. Original Research: Full open access research for “Structural Brain Connectome and Cognitive Impairment in Parkinson’s Disease” by Sebastiano Galantucci, Federica Agosta, Elka Stefanova, Silvia Basaia, Martijn P. van den Heuvel, Tanja Stojković, Elisa Canu, Iva Stanković, Vladana Spica, Massimiliano Copetti, Delia Gagliardi, Vladimir S. Kostić, Massimo Filippi in Radiology. Published online December 7 2016 doi:10.1148/radiol.2016160274
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[cbtabs][cbtab title=”MLA”]RSNA “Imaging Links Structural Brain Changes and Cognitive Decline in Parkinson’s.” NeuroscienceNews. NeuroscienceNews, 8 December 2016. <https://neurosciencenews.com/brain-structure-cognition-parkinsons-5711/>.[/cbtab][cbtab title=”APA”]RSNA (2016, December 8). Imaging Links Structural Brain Changes and Cognitive Decline in Parkinson’s. NeuroscienceNew. Retrieved December 8, 2016 from https://neurosciencenews.com/brain-structure-cognition-parkinsons-5711/[/cbtab][cbtab title=”Chicago”]RSNA “Imaging Links Structural Brain Changes and Cognitive Decline in Parkinson’s.” https://neurosciencenews.com/brain-structure-cognition-parkinsons-5711/ (accessed December 8, 2016).[/cbtab][/cbtabs]
Structural Brain Connectome and Cognitive Impairment in Parkinson’s Disease
Purpose To investigate the structural brain connectome in patients with Parkinson disease (PD) and mild cognitive impairment (MCI) and in patients with PD without MCI.
Materials and Methods This prospective study was approved by the local ethics committees, and written informed consent was obtained from all subjects prior to enrollment. The individual structural brain connectome of 170 patients with PD (54 with MCI, 116 without MCI) and 41 healthy control subjects was obtained by using deterministic diffusion-tensor tractography. A network-based statistic was used to assess structural connectivity differences among groups.
Results Patients with PD and MCI had global network alterations when compared with both control subjects and patients with PD without MCI (range, P = .004 to P = .048). Relative to control subjects, patients with PD and MCI had a large basal ganglia and frontoparietal network with decreased fractional anisotropy (FA) in the right hemisphere and a subnetwork with increased mean diffusivity (MD) involving similar regions bilaterally (P < .01). When compared with patients with PD without MCI, those with PD and MCI had a network with decreased FA, including basal ganglia and frontotemporoparietal regions bilaterally (P < .05). Similar findings were obtained by adjusting for motor disability (P < .05, permutation-corrected P = .06). At P < .01, patients with PD and MCI did not show network alterations relative to patients with PD without MCI. Network FA and MD values were used to differentiate patients with PD and MCI from healthy control subjects and patients with PD without MCI with fair to good accuracy (cross-validated area under the receiver operating characteristic curve [principal + secondary connected components] range, 0.75–0.85).
Conclusion A disruption of structural connections between brain areas forming a network contributes to determine an altered information integration and organization and thus cognitive deficits in patients with PD. These results provide novel information concerning the structural substrates of MCI in patients with PD and may offer markers that can be used to differentiate between patients with PD and MCI and patients with PD without MCI.
“Structural Brain Connectome and Cognitive Impairment in Parkinson’s Disease” by Sebastiano Galantucci, Federica Agosta, Elka Stefanova, Silvia Basaia, Martijn P. van den Heuvel, Tanja Stojković, Elisa Canu, Iva Stanković, Vladana Spica, Massimiliano Copetti, Delia Gagliardi, Vladimir S. Kostić, Massimo Filippi in Radiology. Published online December 7 2016 doi:10.1148/radiol.2016160274