Evidence of small vessel disease in patients with juvenile myoclonic epilepsy based on the peak width of skeletonized mean diffusivity.

Objectives: Peak width of skeletonized mean diffusivity (PSMD) is a novel marker of white matter changes probably due to small vessel disease. This study aimed to investigate the presence of white matter changes in juvenile myoclonic epilepsy (JME) using PSMD.

Methods: We enrolled patients with JME and age- and sex-matched healthy controls. We performed diffusion tensor imaging (DTI) using a three tesla magnetic resonance imaging scanner. We measured the PSMD based on DTI in several steps, including preprocessing, skeletonization, application of a custom mask, and histogram analysis, using the FSL program. We compared the PSMD between patients with JME and healthy controls and the PSMD according to the antiseizure medication (ASM) response among the patients with JME. We also performed a correlation analysis between the PSMD and clinical factors in patients with JME.

Results: We enrolled the 42 patients with newly diagnosed JME and 42 healthy controls. There was a significant difference in the PSMD between patients with JME and healthy controls. PSMD was higher in patients with JME than in healthy controls (2.234 vs. 2.085 × 10^-4 mm²/s, p = 0.013). In addition, the PSMD was higher in patients with JME who were ASM poor responders than in those who were ASM good responders (2.586 vs. 2.176 × 10^-4 mm²/s, p = 0.007). The PSMD was positively correlated with age (r = 0.364, p = 0.017).

Conclusion: Patients with JME have a higher PSMD than healthy controls, indicating evidence of white matter changes in patients with JME. In addition, white matter changes are related to the ASM response in patients with JME. This finding also highlights the potential of PSMD as a marker for detecting white matter changes probably due to small vessel disease in patients with epilepsy, which would require further studies.