MRI Correlates of Parkinson’s Disease Progression: A Voxel Based Morphometry Study

Abstract

We investigated structural brain differences between a group of early-mild PD patients at different phases of the disease and healthy subjects using voxel-based morphometry (VBM). 20 mild PD patients compared to 15 healthy at baseline and after 2 years of follow-up. VBM is a fully automated technique, which allows the identification of regional differences in the gray matter enabling an objective analysis of the whole brain between groups of subjects. With respect to controls, PD patients exhibited decreased GM volumes in right putamen and right parietal cortex. After 2 years of disease, the same patients confirmed GM loss in the putamen and parietal cortex; a significant difference was also observed in the area of pedunculopontine nucleus (PPN) and in the mesencephalic locomotor region (MLR). PD is associated with brain morphological changes in cortical and subcortical structures. The first regions to be affected in PD seem to be the parietal cortex and the putamen. A third structure that undergoes atrophy is the part of the inferior-posterior midbrain, attributable to the PPN and MLR. Our findings provide new insight into the brain involvement in PD and could contribute to a better understanding of the sequence of events occurring in these patients.

Brain MRI Reveals Ascending Atrophy in Parkinson's Disease Across Severity

“…Loss of gray matter in Parkinson's disease is pathological, and additive to the normal aging process (45,77,78). This study found pathological gray matter degeneration in subcortical regions of the cholinergic basal forebrain and amygdala, but found general sparing of hippocampal and neo-cortical regions in a population of advanced Parkinson's disease patients.…”

“…However, voxel-based morphometry (VBM), a technique known to agree with findings from autopsy studies and other imaging modalities (39)(40)(41), allows for the measurement of many gray matter structures implicated in PD ranging from basal forebrain to the neocortex. Past VBM studies of PD have identified neurodegeneration in the basal forebrain (21,22), amygdala (24,42), hippocampus (43,44), and neocortex (42,45).…”

Deficient supplementary motor area at rest: Neural basis of limb kinetic deficits in Parkinson's disease

“…While there is substantial literature on the involvement of the left IPL for gestural performance in general, its contribution for gestural performance in PD is still under investigation. Some atrophy of the left IPL is a common in PD without dementia (Fioravanti et al, ; Meppelink et al, ) and aberrant IPL activation is detected during motor tasks (Herz et al, ; Wu & Hallett, ) and rest (Pan et al, ). During the execution of a pantomime task, PD patients showed increased activation of the left IPL to aim at proper task performance (Matt et al, 2017).…”

The pattern of gray matter atrophy in Parkinson’s disease differs in cortical and subcortical regions

“…Several recent studies demonstrated [7,22,23], yet others failed to find [24,25], reduced cortical volume in PD. The exact reason for these discrepancies is not known but different methodologies (region of interest vs. voxel-based) may be one possible contributory factor.…”