Morphologic Changes in Primary Somatosensory System May Fuel Restless Leg Symptoms

A study published in Neurology demonstrates that morphologic changes occurring in the primary somatosensory cortex in conjunction with callosal subdivision may drive the sensory functional component found in restless leg syndrome (RLS).

A total of 28 patients with RLS and 51 healthy control patients were included in the study. Investigators assessed patients using magnetic resonance imaging, and software-based whole-brain segmentation analyses performed quantitative assessments of cortical brain thickness. In addition, a vertex-wise analysis and a method for classifying cortical surface were used to evaluate cortical thickness. Investigators also measured the thickness of the corpus callosum’s midbody connecting the postcentral gyri in the 2 hemispheres.

At time of enrollment, participants with RLS were in its severe stage. Compared with control patients, patients with RLS symptoms experienced a morphologic change in the brain somatosensory system. Greater cortical thinning occurred in the left (cluster size, 7743; T score, 6.23; FDR-corrected P <.001) and right (cluster size, 7658; T score, 5.46; FDR-corrected P <.001) postcentral gyrus of patients with RLS vs control patients.

On average, there was a significant 7.5% decrease in cortical thickness in the bilateral postcentral gyrus among patients with RLS (P <.0001). In addition, a significant decrease in the corpus callosum posterior midbody was observed in patients with RLS (P <.008). No significant differences in gray matter were observed between the 2 groups.

The relatively small number of patients with RLS represents a potential limitation of the exploratory imaging analysis.

The researchers suggest that the study’s findings “could provide new insights into the pathophysiology underlying RLS sensory symptomatology and could be a potential imaging marker for RLS.”

Reference

Lee BY, Kim J, Connor JR, et al. Involvement of the central somatosensory system in restless legs syndrome: A neuroimaging study [published online April 25, 2018]. Neurology. doi: 10.1212/WNL.0000000000005562