Cortical thickness in Parkinson's disease: a coordinate-based meta-analysis

Abstract

Parkinson's disease (PD) is a common age-related neurodegenerative disease that affects the structural architecture of the cerebral cortex. Cortical thickness (CTh) via surface-based morphometry (SBM) analysis is a popular measure to assess brain structural alterations in the gray matter in PD. However, the results of CTh analysis in PD lack consistency and have not been systematically reviewed. We conducted a comprehensive coordinate-based meta-analysis (CBMA) of 38 CTh studies (57 comparison datasets) in 1,843 patients with PD using the latest seed-based d mapping software. Compared with 1,172 healthy controls, no significantly consistent CTh alterations were found in patients with PD, suggesting CTh as an unreliable neuroimaging marker for PD. The lack of consistent CTh alterations in PD could be ascribed to the heterogeneity in clinical populations, variations in imaging methods, and underpowered small sample sizes. These results highlight the need to control for potential confounding factors to produce robust and reproducible CTh results in PD.

Keywords: Parkinson's disease; coordinate-based meta-analysis; cortical thickness; seed-based d mapping; surface-based morphometry.

Figure 1

PRISMA flow chart describing the study selection process. PRISMA, Preferred Reporting Items of Systematic Review and Meta-Analysis; PD, Parkinson’s disease; SBM, surface-based morphometry; CTh, cortical thickness; ROI, region of interest.

Figure 2

Meta-regression analyses of clinical variables with cortical thickness. (A) A longer disease duration was associated with lower CTh in the supplementary motor area/cingulate cortex (MNI coordinates: x = –4, y = –2, z = 46; BA 24; SDM-Z = –2.31; TFCE-based FWE corrected p = 0.009; voxels = 392). (B) A lower MMSE score in the PD sample was associated with lower CTh in the right superior temporal gyrus/rolandic operculum (MNI coordinates: x = 54, y = –22, z = 12; BAs 48 and 22; SDM-Z = 7.05; TFCE-based FWE corrected p = 0.001; voxels = 999), left superior/middle temporal gyri (MNI coordinates: x = –62, y = –12, z = 0; BAs 48, 21, and 22; SDM-Z = 6.65; TFCE-based FWE corrected p = 0.009; voxels = 441), and left inferior temporal gyrus (MNI coordinates: x = –60, y = –20, z = –24; BAs 20 and 21; SDM-Z = 6.57; TFCE-based FWE corrected p = 0.03; voxels = 169). (C) A higher LEDD in the PD sample was associated with lower CTh in the medial prefrontal cortex/anterior cingulate cortex (MNI coordinates: x = 4, y = 32, z = 38; BAs 32, 24, 10, and 8; SDM-Z = –1.66; TFCE-based FWE corrected p = 0.029; voxels = 1441). CTh, cortical thickness; MNI, Montreal Neurological Institute; BA, Brodmann area; SDM, seed-based d mapping; TFCE, threshold-free cluster enhancement; FWE, family-wise error; PD, Parkinson’s disease; LEDD, levodopa equivalent daily dose.