Neuroimaging essentials in essential tremor: a systematic review.

Area of Science:

• Neuroscience
• Medical Imaging
• Neurology

Background:

• Essential tremor (ET) is a central nervous system disorder.
• Neuroimaging offers potential for ET diagnostics and research.
• The precise role of neuroimaging in ET research and clinical practice remains unclear.

Purpose of the Study:

• To systematically review neuroimaging techniques used in essential tremor research.
• To evaluate the quality and discuss the findings of existing neuroimaging studies on ET.
• To contextualize these findings within the known pathophysiology of ET.

Main Methods:

• Systematic literature search using terms like "essential tremor" and "familial tremor" combined with imaging keywords (MRI, VBM, DWI, fMRI, PET, SPECT).
• Summarized and discussed the quality and external validity of 48 selected neuroimaging studies.
• Categorized studies into structural (19) and functional/metabolic (29).

Main Results:

• Functional imaging studies consistently showed cerebellar hyperactivity during rest and tremor in ET patients.
• Evidence suggests involvement of the thalamus, inferior olive, and red nucleus.
• Structural imaging studies yielded less consistent results.

Conclusions:

• Neuroimaging highlights the cerebellum as consistently involved in ET pathophysiology.
• GABAergic dysfunction is a potential key factor in ET.
• Heterogeneous patient groups and methodological variations contribute to study inconsistencies.
• More stringent criteria and advanced techniques, including multimodal imaging, are needed for improved research.
• Current clinical utility of neuroimaging in ET is limited.