Regional Homogeneity In Children With Severe And Non-severe Primary Monosymptomatic Nocturnal Enuresis Using Resting-state Functional Magnetic Resonance Imaging

BackgroundNocturnal enuresis(NE)is defined as unconscious leakage of urine during sleep at least once a month in children over 5 years old and lasts for more than 3 months by World Health Organization.Primary monosymptomatic nocturnal enuresis(PMNE)means that children with nocturnal enuresis over 5 years old have never obtained nocturnal urinary control for more than 6 months without daytime lower urinary tract symptoms.NE is very common among children.The epidemiological survey in China shows that the overall incidence of children aged 5-18 years is 4.07%.In addition to bed wetting,NE will also affect children’s academic performance and quality of life,give children and their families greater psychological pressure,and affect their development.At present,it is considered that the three main factors in the pathological mechanism of NE are nocturnal polyuria,bladder dysfunction and arousal disorder,The central nocturnal bladder dysfunction,cognitive impairment and genetic factors are also important causes,but the specific central pathogenesis of PMNE is still unclear.Resting state functional magnetic resonance imaging(Rs-fMRI)measures continuous brain activity by recording blood oxygen level dependent(BOLD)signals,the analysis of amplitude of low frequency(Alff)and regional consistency(ReHo)are two commonly methods used parameter analysis in RS fMRI research.Previous studies by our team have found abnormal brain function in prefrontal cortex and occipital lobe of children with PMNE.NE is a self-healing disease,and children with frequent bed wetting are more difficult to heal themselves than children with mild bed wetting symptoms,which is often associated with underlying bladder dysfunction.However,there is no relevant study to clarify whether the abnormal brain function of children with PMNE is related to the severity of the disease.This study compared the ReHo differences among non-severe group,severe group and normal group to explore the differences in brain function characteristics of children with different severity of PMNE.ObjectiveRs-fMRI was used to analyze the brain regions with abnormal brain function in children with PMNE by comparing the ReHo changes among severe group,non-severe group and control group.Then we explored the relationship between the severity of disease and brain function in PMNE children by comparing the severe group with the non-severe group.MethodsWe selected 39 children with PMNE(20 males and 19 females),aged(11.9 ± 2.6 years),and 33 children(18 males and 15 females),aged(11.8±3.0 years),who needed surgery due to upper urinary tract diseases and whose lower urinary tract function was normal by conventional urodynamic examination(cud),as the normal control group.According to the consensus of Chinese experts,PMNE children is divided into non-severe group(number of bed wetting nights per week<4)(n=14)and severe group(number of bed wetting nights per week>4)(n=25);Rs-fMRI images of all children were collected,and the ReHo difference under the effect of disease was analyzed by one-way ANOVA.The t-test was used for post test to compare the differences of brain function characteristics among the three groups.ResultsOne-way ANOVA:supplementary motor area(Disease effect).There was no statistical difference in ReHo between the non-severe group and the severe group.Compared with the control group,the left inferior parietal lobule,left inferior frontal gyrus and supplementary motor area were abnormal in the non-severe group;the right inferior temporal gyrus,left superior frontal gyrus and supplementary motor area were abnormal in the severe group.All of the above results were AlphaSim corrected(voxel level P<0.005,P<0.05 after correction was considered statistically different).Correlation analysis:there was no significant correlation between the change of ReHo and the number of bed wetting nights per week(r=-0.26,P=0.11).Conclusion1.The abnormal function of the inferior parietal lobe,inferior frontal gyrus and supplementary motor area were found in the non-severe group with PMNE children,and the abnormal function of the inferior temporal gyrus,superior frontal gyrus and supplementary motor area were found in the severe group with children.These abnormal brain areas may be related to bladder dysfunction,mood or memory impairment in children.2.There are differences in abnormal brain regions between severe group and non-severe group compared with the control group,indicating that NE is caused by multiple factors.The reason why children with severe NE are difficult to heal may not be related to the development of central nervous system,but may be related to underlying bladder dysfunction.