Gray matter atrophy in Parkinson’s disease with dementia: evidence from meta-analysis of voxel-based morphometry studies

Abstract

Voxel-based morphometry (VBM) studies have provided cumulative evidence of gray matter (GM) atrophy in patients with Parkinson's disease with dementia (PDD) relative to healthy controls (HC). However, not all the studies reported entirely consistent findings. A systematic search for VBM studies of PDD patients and HC subjects published in PubMed and Embase databases from January 2000 to June 2012 was conducted. Meta-analysis was performed by using a newly improved voxel-based meta-analytic technique, effect size signed differential mapping, to quantitatively explore the GM abnormalities between PDD patients and HC subjects. A total of 6 cross-sectional VBM studies involving 105 PDD patients and 131 HC subjects met the inclusion criteria. Considerable regional GM decrease was detected in the medial temporal lobe (MTL) and basal ganglia. The findings of the present study remained largely unchanged in the entire brain jackknife sensitivity analyses. Meta-regression showed dementia severity correlated with the left MTL. The present meta-analysis provided evidence of PDD-related GM atrophy, which suggested MTL and basal ganglia were implicated in PDD. This finding could give us further insight about the pathophysiological basis revealed by structure abnormalities in PDD.

Longitudinal Study of Gray Matter Changes in Parkinson Disease

“…Previous studies have reported GMV loss in patients with PD with dementia (for a review, see Pan et al 20 ). The present study extended the knowledge by showing that GMV loss can be found even in patients with early-stage PD.…”

Reduced CA2–CA3 Hippocampal Subfield Volume Is Related to Depression and Normalized by l-DOPA in Newly Diagnosed Parkinson’s Disease

“…We did not find any evidence for extra-hippocampal structural alterations in newly diagnosed PD patients with spared cognitive functions relative to control participants, which is consistent with previous findings (65, 66). Two recent meta-analyses of VBM studies in PD failed to prove hippocampal gray matter reduction (67, 68), whereas a marked medial temporal lobe atrophy was reported in PD patients with dementia (69). The fact that VBM did not reveal hippocampal volume loss in our patients is neither surprising nor contradictory.…”

False positive rates in Voxel-based Morphometry studies of the human brain: Should we be worried?

“…Over the past 15 years, VBM has been used successfully to investigate a wide range of neurological and psychiatric disorders including, but not limited to, Alzheimer's disease (Li et al, 2012), Parkinson's disease (Pan et al, 2013), multiple sclerosis (Lansley et al, 2013), unipolar (Lai, 2013) and bipolar (Selvaraj et al, 2012) depression, anxiety disorders (Radua et al, 2010) and psychosis (Honea et al, 2005;Bora et al, 2011Mechelli et al, 2011. In addition, VBM has been used to compare groups of healthy subjects who differ with respect to biological or environmental variables of interest such as age (Kennedy et al, 2009;Takahashi et al, 2011), gender (Takahashi et al, 2011;Sacher et al, 2013), number of spoken languages (Mechelli et al, 2004), and exposure to stressful life events (Papagni et al, 2011).…”