Metabolic Patterns across core features in Dementia with Lewy Bodies (DLB)

Abstract

Objective

To identify brain regions whose metabolic impairment contributes to DLB clinical core features expression and to assess the influence of severity of global cognitive impairment on the DLB‐hypometabolic‐pattern.

Methods

Brain FDG‐PET and information on core features were available in 171 patients belonging to the imaging repository of the European DLB‐consortium. Principal component analysis was applied to identify brain regions relevant to the local data variance. A linear regression model was applied to generate core feature‐specific patterns controlling for the main confounding variables (MMSE, Age, Education, Gender, and Center). Regression analysis to the locally‐normalized intensities was performed to generate a MMSE score‐sensitive map.

Results

Parkinsonism negatively covaried with bilateral parietal, precuneus and anterior cingulate metabolism, visual‐hallucinations with bilateral dorsolateral‐frontal cortex, posterior cingulate and parietal metabolism and RBD with bilateral parieto‐occipital cortex, precuneus and ventrolateral‐frontal metabolism. VH and RBD shared a positive covariance with metabolism in medial temporal lobe, cerebellum, brainstem, basal ganglia, thalami, orbitofrontal and sensorimotor cortex. Cognitive fluctuations negatively covaried with occipital metabolism and positively with parietal lobes metabolism. MMSE positively covaried with metabolism in left superior frontal gyrus, bilateral‐parietal cortex, and left precuneus, and negatively with metabolism in insula, medial frontal gyrus, hippocampus in the left hemisphere and in right cerebellum.

Interpretation

Regions of more preserved metabolism are relatively consistent across the variegate DLB spectrum. By contrast, core features were associated to more prominent hypometabolism in specific regions thus suggesting a close clinical‐imaging correlation, reflecting the interplay between topography of neurodegeneration and clinical presentation in DLB patients.

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