Voxel-Based Morphometry of Cerebellar Lobules in Essential Tremor

Richard Ågren; Amar Awad; Patric Blomstedt; Anders Fytagoridis

doi:10.3389/fnagi.2021.667854

Voxel-Based Morphometry of Cerebellar Lobules in Essential Tremor

Front Aging Neurosci. 2021 Jun 10:13:667854. doi: 10.3389/fnagi.2021.667854. eCollection 2021.

Authors

Richard Ågren¹, Amar Awad^{2

3

4}, Patric Blomstedt², Anders Fytagoridis⁵

Affiliations

¹ Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
² Unit of Functional and Stereotactic Neurosurgery, Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
³ Physiology Section, Department of Integrative Medical Biology, Umeå University, Umeå, Sweden.
⁴ Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden.
⁵ Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.

Abstract

Background: The 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.

Objective: To compare the volumes of cerebellar lobules in ET patients with those in healthy controls (HCs) using an automated segmentation pipeline.

Methods: Structural 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.

Results: Total 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.

Conclusion: A 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.

Keywords: cerebellum; essential tremor; lobule volume; structural MRI; voxel-based morphometry.