Introduction

Sensorimotor abnormality occurs frequently in patients with end-stage renal disease (ESRD). Approximately 30% of ESRD patients exhibit discomfort sensation such as itch, crawling, aching in the limbs and occur involuntary movement particularly in those who are undergoing hemodialysis [1,2]. This type of sensorimotor abnormality appear or worsen during rest time especially at night, which is the leading cause of poor sleep, decreased quality of life and increased mortality [3]. Several neuroimaging studies suggested that the sensorimotor pathway, subserving sensory modulation and motor activity, is was mediated by the insular [4,5]. However, the pathophysiology of sensorimotor dysfunction in patients with ESRD remains poorly understood.

Methods

3D high-resolution strcutural imaging was applied in 29 patients with uremic restless legs (uRLS group) and 29 healthy volunteers (control group) with maintenance hemodialysis, The grey matter volume of insular was assessed using a voxel-based morphometry (VBM) analysis.and functional connectivity of insular variation was evaluated by a seed-based correlation analysis, while the seed was choosed as the significant difference of grey matter volume. Spearman correlation analysis was used to explore the significant correlation of functional connectivity and RLS score.The relationship between brain alterations and clinical variables were investigated with Logistic stepwise multiple regression analysis.

Results

Compared with the control group, the area with reduced gray matter volume in the uRLS group was located on the left posterior insular (P<0.05, FWE correction). Taking the left post insular as a seed region, we further found reduced functional connectivity in patients mainly between the insular and primary sensorimotor cortex,(S1), supplementary motor areas(SMA),and posterior mid-cingulate gyrus(P<0.05,FDR corrected). In uRLS group, the severity score of RLS was negatively correlated with insular-S1 functional connectivity(P<0.05,FDR corrected), while the hemoglobin level was negetively correlated with functional connectivity degree of insular-S1 (r=-0.449 ,P=0.015, FDR corrected).

Conclusion

the altered morphology of post insular was revealed in uRLS patients, abnormal sensorimotor activities in patients with RLS is closely associated with reduced functional connectivity of insular-S1.Low hemoglobin level was the most important risk factor related to brain functional connectivity feature.

References

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