Reproducibility of Cerebellar involvement as quantified by consensus structural MRI biomarkers in Advanced Essential Tremor [Registered Report Stage 1 Protocol]
Abstract: Essential Tremor (ET) is the most prevalent movement disorder with poorly understood etiology. Some neuroimaging studies report cerebellar involvement, whereas others find no significant differences between ET and control groups. This discrepancy may stem from the underpowered studies as well as differences in Magnetic Resonance Imaging (MRI) acquisition and processing. To help resolve these differences, we plan to analyze the structural MRI scans from 1) an advanced ET cohort and normal controls (NC) acquired at the Montreal Neurological Institute and 2) additional NC subjects from PPMI and ADNI. We will test the hypothesis that the cerebellar involvement in advanced ET can be detected with multiple neuroimaging biomarkers: 1) cerebellar VBM, 2) cerebellar gray/white matter volumetry, and 3) cerebellar lobular volumetry. We will rigorously evaluate the sensitivity of the hypothesis tests to the underlying methods by varying image processing algorithms and confounder control design choices. Subsequently, we will also report the cortical changes associated with cerebellar “degeneration” in the advanced ET in an exploratory analysis.