White Matter Microstructural Differences between Essential Tremor and Parkinson Disease, Evaluated Using Advanced...

Area of Science:

• Neurology
• Neuroimaging
• Neuroscience

Background:

• Essential tremor (ET) is a prevalent, slowly progressive neurological disorder causing kinetic tremors in the upper limbs.
• ET shares motor symptoms with Parkinson disease (PD), but their relationship remains unclear.
• Understanding white matter differences is key to differentiating these conditions.

Purpose of the Study:

• To investigate and compare white matter microstructural integrity between ET and PD patients.
• To identify specific white matter regions that differ between ET and PD using advanced neuroimaging techniques.

Main Methods:

• Employed diffusion tensor imaging (DTI) and fixel-based analysis (FBA) on 17 ET and 68 PD patients.
• Acquired diffusion MRI data from GE and Philips scanners with varying diffusion directions.
• Utilized FSL for fractional anisotropy maps and MRtrix3 for FBA metrics (fiber density, bundle, and cross-section).

Main Results:

• ET patients exhibited significantly lower fiber density, fiber bundle, and fiber density bundle cross-section in the corpus callosum and left tapetum compared to PD patients.
• Lower fractional anisotropy values were observed in ET compared to PD, predominantly in the corpus callosum, corona radiata, and cingulum.
• Both FBA metrics and DTI demonstrated significant differences in white matter integrity between ET and PD.

Conclusions:

• Advanced diffusion-based metrics effectively differentiate white matter microstructural characteristics between ET and PD.
• These findings enhance the understanding of disparate motor-associated diseases with distinct phenotypes.
• Neuroimaging offers valuable insights into the underlying pathology of ET and PD.