Brain Network Disruption in Parkinson’s, Cognitive Impairment

MRI can show disruptions in brain networks in the brains of people with Parkinson’s disease (PD) who have cognitive impairment, according to a study published in Radiology.

Researchers from Italy, Serbia, and the Netherlands performed a prospective study to compare the structural brain connectome in 54 patients with PD and mild cognitive impairment (MCI) and 116 patients with PD without MCI. Forty-one healthy controls also participated in the study. All subjects underwent deterministic diffusion-tensor tractography and a network-based statistic was used to assess structural connectivity differences among groups.

“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,” coauthor Federica Agosta, MD, PhD, said in a release.  “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 results showed that patients with PD and MCI had global network alterations when compared with both control subjects and patients with PD without MCI. 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, the authors wrote.[[{"type":"media","view_mode":"media_crop","fid":"54978","attributes":{"alt":"Federica Agosta, MD, PhD","class":"media-image media-image-right","id":"media_crop_9412829533567","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"6881","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"Federica Agosta, MD, PhD","typeof":"foaf:Image"}}]]

Subjects with PD but not MCI had decreased FA, including basal ganglia and frontotemporoparietal regions bilaterally, compared with those with MCI. Similar findings were obtained by adjusting for motor disability, 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.

The researchers suggested that these findings may offer markers to differentiate PD patients with and without cognitive deficits. “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,” Agosta said. Further study is planned.