Understanding the pathophysiology of essential tremor through advanced neuroimaging: a review

Essential tremor (ET) is one of the most common neurological diseases; but aetio-pathogenesis of ET is largely unknown. Major advances in neuroimaging may help us understand the mechanisms and networks involved in ET. Most commonly employed techniques include functional and structural neuroimaging. Functional imaging studies suggest that tremors in ET are of central origin with role of olivo-cerebellar and cerebello-thalamo-cortical pathways in tremor generation. Apart from tremors, ET is also characterised by cognitive dysfunction. Functional magnetic resonance imaging (fMRI) studies suggest the role of cerebellum posterior lobules, dorsolateral prefrontal cortex and parietal lobules in cognitive impairment in ET. Positron emission tomography studies indicate the role of gamma-aminobutyric-acid dysfunction in tremor generation while most of the structural imaging studies (diffusion tensor imaging, voxel based morphometry, T2*-relaxometry on magnetic resonance imaging) along with magnetic resonance spectroscopic imaging point toward neurodegeneration. This review focuses on recent findings in the field of imaging in ET which may help understand the disease pathogenesis and mechanisms.