White matter hyperintensities on brain magnetic resonance imaging: comparison of early-onset and late-onset restless legs syndrome.

OBJECTIVE: Previous studies have suggested that early-onset RLS (EOR) and late-onset RLS (LOR) might have different etiopathophysiologies. Few previous studies have examined accumulation of cerebrovascular ischemic changes as a potential cause of LOR.

METHODS: We recruited 39 RLS subjects (LOR: defined as age of RLS onset ≥45, n = 18 and EOR: age of onset <45; n = 21); and 39 healthy control subjects matched on age and sex. Structural magnetic resonance imaging (MRI) of the brain was performed for each subject, and images were graded for severity of periventricular white matter hyperintensities (PVH) and deep white matter hyperintensities (DWMH) independently by trained raters according to standardized methods.

RESULTS: Interrater reliabilities were 0.861 (p <0.001) for PVH and 0.900 (p <0.001) for DWMH. LOR subjects had a significantly higher grade of DWMH than the EOR subjects (p = 0.043) and age- and sex-matched controls (p = 0.015). In contrast, there was no difference in DWMH severity rating between the EOR group and the EC group or in PVH severity between the LOR or EOR groups and their age-matched controls.

CONCLUSION: Our findings suggest that the presence and severity of DWMH is associated with LOR, but not with EOR. Further examination of the contribution of cerebrovascular disease to the etiopathogenesis of LOR is warranted.