Structural Correlates of the Sensorimotor Cerebellum in Parkinson's Disease and Essential Tremor

Abstract

BackgroundParkinson's disease (PD) and essential tremor (ET) are commonly encountered movement disorders. Pathophysiologic processes that localize to the cerebellum are described in both. There are limited studies investigating cerebellar structural changes in these conditions, largely because of inherent challenges in the efficiency of segmentation.MethodsWe applied a novel multiatlas cerebellar segmentation method to T1‐weighted images in 282 PD and 111 essential tremor patients to define 26 cerebellar lobule volumes. The severity of postural and resting tremor in both populations and gait and postural instability in PD patients were defined using subscores of the UPDRS and Washington Heights‐Inwood Genetic Study motor scales. These clinical measurements were related to lobule volume size. Multiple comparisons were controlled using a false discovery rate method.ResultsGroup differences were identified between ET and PD patients, with reductions in deep cerebellar nucleus volume in ET versus reduced lobule VI volume in PD. In ET patients, lobule VIII was negatively correlated with the severity of postural tremor. In PD patients, lobule IV was positively correlated with resting tremor and total tremor severity. We observed differences in cerebellar structure that localized to sensorimotor lobules of the cerebellum. Lobule volumes appeared to differentially relate to clinical symptoms, suggesting important clinicopathologic distinctions between these conditions. These results emphasize the role of the cerebellum in tremor symptoms and should foster future clinical and pathologic investigations of the sensorimotor lobules of the cerebellum. © 2020 International Parkinson and Movement Disorder Society

Anatomical texture patterns identify cerebellar distinctions between essential tremor and Parkinson's disease

“…First, it is interesting to note that differences in the vermis can explain symptomatic differences since it has been shown that such structures mediate gait and balance (Baumann, 2012;Stoodley et al, 2012). Secondly, the differences found in lobules VI and VIII are in line with studies indicating that these lobules perform sensorimotor functions in the cerebellum (Lopez et al, 2020;Lewis et al, 2007;Sharifi et al, 2014;Benninger et al, 2009).…”

“…We assessed structural features at both a region-wise and voxel-wise level using two methods: i) MRI intensity using a classical VBM framework, and ii) a texture-based similarity method. We hypothesized that these analyses would provide complimentary results allowing for an assessment of the methodologic tradeoffs, as well as extend previous analyses that employed cerebellar volumetric assessments (Lopez et al, 2020), and VBM comparisons (Lin et al, 2013). We further hypothesized that a texture-based approach would provide greater sensitivity to group differences since this approach may alleviate limitations of volumetric and VBM studies.…”

“…This study revealed vermal atrophy which is more pronounced in ET patients with head tremor, but did not find anatomical differences for patients suffering from other types of tremors. A recent volumetric study evaluated the relationship of sensorimotor function and cerebellar atrophy (Lopez et al, 2020). This study identified group differences between PD and ET in the corpus medullar, lobule VI, lobules VIII.…”

“…Recent studies emphasize distinct changes to cerebellar structures in Parkinson's disease (PD) and essential tremor (ET) populations (Lin et al, 2013;Lopez et al, 2020). Both disorders commonly present with tremor and progressive worsening of motor function.…”

A Radiomics Approach to Predicting Parkinson’s Disease by Incorporating Whole-Brain Functional Activity and Gray Matter Structure

“…Third, cerebellum networks were left out in the model. Although the key molecular events that provoke PD have not been fully understood and the underlying mechanisms involving cerebellum were relatively less reported, considerable evidence has indicated that cerebellum plays an important role in sensorimotor dysregulation and has now received growing attention (Lopez et al, 2020;Maas et al, 2020). For future studies, we will include the cerebellum, and increase our sample size in order to obtain different subgroups based on disease stages.…”