Voxel-Based Morphometry of Cerebellar Lobules in Essential Tremor.

Anders Fytagoridis,Amar Awad,Richard Ågren,Patric Blomstedt

doi:10.3389/fnagi.2021.667854

Anders Fytagoridis, Amar Awad + Show 2 more

Open Access

https://doi.org/10.3389/fnagi.2021.667854

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Abstract

BackgroundThe extent of neurodegeneration underlying essential tremor (ET) remains a matter of debate. Despite various extents of cerebellar atrophy on structural magnetic resonance imaging (MRI), previous studies have shown substantial heterogeneity and included a limited number of patients. Novel automated pipelines allow detailed segmentation of cerebellar lobules based on structural MRI.ObjectiveTo compare the volumes of cerebellar lobules in ET patients with those in healthy controls (HCs) using an automated segmentation pipeline.MethodsStructural MRI scans of ET patients eligible for deep brain stimulation (n = 55) and of age-matched and gender-matched HCs (n = 55, from the IXI database) were segmented using the automated CEREbellum Segmentation pipeline. Lobule-specific volume differences between the ET and HC groups were evaluated using a general linear model corrected for multiple tests.ResultsTotal brain tissue volumes did not differ between the ET and HC groups. ET patients demonstrated reduced volumes of lobules I-II, left Crus II, left VIIB, and an increased volume of right X when compared with the HC group.ConclusionA large cohort of ET patients demonstrated subtle signs of decreased cerebellar lobule volumes. These findings oppose the hypothesis of localized atrophy in cerebellar motor areas in ET, but not the possibility of cerebellar pathophysiology in ET. Prospective investigations using alternative neuroimaging modalities may further elucidate the pathophysiology of ET and provide insights into diagnostic and therapeutic approaches.

Highlights

Essential tremor (ET) is the most prevalent movement disorder, affecting approximately 4% of the population over 40 years of age (Zesiewicz et al, 2010)
Structural magnetic resonance imaging (MRI), which allows for voxel-based morphometric (VBM) analysis, has demonstrated diverse cortical and cerebellar volumetric changes in ET patients
Decreased cerebellar gray matter has been observed in groups of ET patients (Benito-Leon et al, 2009; Bhalsing et al, 2014; Gallea et al, 2015; Dyke et al, 2017)

Summary

Introduction

Essential tremor (ET) is the most prevalent movement disorder, affecting approximately 4% of the population over 40 years of age (Zesiewicz et al, 2010). It was initially believed to be a benign motor disorder, reports have demonstrated increased occurrences of mood disorders, cognitive disorders, and early mortality in ET patients Structural magnetic resonance imaging (MRI), which allows for voxel-based morphometric (VBM) analysis, has demonstrated diverse cortical and cerebellar volumetric changes in ET patients. A recent meta-analysis of 16 structural MRI investigations proposed that previously reported gray matter abnormalities in ET might be related to methodological heterogeneity and small or diverse cohorts, thereby indicating the need for larger studies using standardized protocols (Luo et al, 2019). Despite various extents of cerebellar atrophy on structural magnetic resonance imaging (MRI), previous studies have shown substantial heterogeneity and included a limited number of patients. Novel automated pipelines allow detailed segmentation of cerebellar lobules based on structural MRI

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