Abnormalities in event-related potential and brainstem auditory evoked response in children with nocturnal enuresis

Impaired selective attention in patients with severe primary monosymptomatic nocturnal enuresis: An event-related potential study

Objectives

Primary monosymptomatic nocturnal enuresis (PMNE) is a very common problem in school age children. It is thought that PMNE represents a maturational lag in the central nervous system of those children. We did this case control study to assess the selective attention and resource allocation in those children using the P300 wave of the Event-Related Potentials (ERPs) and its relation to disease severity.

Methods

Forty four patients with PMNE and twenty three healthy controls were included in this study. Patients were diagnosed according to the criteria of international children's continence society and were classified into two groups; patients with frequent wetting (≥4 episodes/week), and patients with infrequent wetting (<4 episodes/week). ERPs were recorded at Fz, Cz, and Pz locations using odd-ball paradigm. N200 and P300 peak latencies (ms), and N200/P300 peak to peak amplitudes (µV) were measured.

Results

We found significant increase of P300 and N200/P300 interpeak latencies, and significant decrease of P300 amplitudes in frequent wetting group "severe" PMNE compared to healthy controls and infrequent wetting group.

Conclusion

Abnormal selective attention and resource allocation were found in patients with severe PMNE. Measures to improve selective attention might be helpful in treatment of patients with severe PMNE.

Significance

Impaired selective attention might play a role in pathogenesis of severe PMNE and the need for the various measures to improve selective attention may be further studied as a therapeutic tool for patients with severe PMNE.

Pathogenesis and brain functional imaging in nocturnal enuresis: A review

Nocturnal enuresis is a common and distressing developmental disease, which may cause various degrees of psychosocial stress and impairment to self-esteem in affected children as well as agitation to their parents or caregivers. Nevertheless, the etiology and pathogenesis of nocturnal enuresis are not understood. Currently, nocturnal enuresis is generally considered a multifactorial disease associated with a complex interaction of somatic, psychosocial, and environmental factors. A variety of postulations have been proposed to explain the occurrence and progression of nocturnal enuresis, including hereditary aberration, abnormal circadian rhythm of antidiuretic hormone secretion during sleep, bladder dysfunction, abnormal sleep, difficulties in arousal, neuropsychological disorders, and maturational delays of the brain. In recent decades, the introduction of functional neuroimaging technologies has provided new approaches for uncovering the mechanisms underlying nocturnal enuresis. The main neuroimaging modalities have included brain morphometry based on structural magnetic resonance imaging (MRI), task-based and event-related functional MRI (fMRI), and resting-state fMRI. The relevant studies have indicated that nocturnal enuresis is associated with functional and structural alterations of the brain. In this review, we briefly summarized the popular hypotheses regarding the pathogenesis of nocturnal enuresis and the current progress of functional neuroimaging studies in examining the underlying mechanisms thereof.

Retrospective evaluation of early risk factors in children with different types of micturition disorders

AIM

The aetiology of micturition disorders in children is multifactorial and still unclear. The perinatal factors may play a role in the development of children's urinary incontinence. We compared each type of micturition disorders in terms of length of gestation, birthweight, family history of bedwetting and delivery type.

METHODS

Data were from 488 patients of the Department of Pediatrics and Nephrology, Children's Clinical Hospital of the Medical University of Bialystok, and included: age, sex, clinical diagnosis, perinatal history, constipation, history of vesicoureteral reflux, family history of nocturnal enuresis, urodynamic diagnosis, bladder capacity. We performed statistical analysis using Mann-Whitney and Spearman tests.

RESULTS

Combined daytime-nocturnal incontinence made a higher percentage and nocturnal enuresis made a lower percentage of clinical diagnoses in children with low birthweight compared with group of normal birthweight. In children with micturition disorders, lower birthweight was associated with smaller bladder capacity than normal for age.

CONCLUSION

Low birthweight might predispose to combined daytime-nocturnal incontinence. We are the first to show that patients suffering from micturition disorders with low birthweight present lower estimated bladder capacity than age-matched children. Thus, we assume that low birthweight may have strong clinical relevance in children's micturition disorders.

BDNF and NGF gene polymorphisms and urine BDNF-NGF levels in children with primary monosymptomatic nocturnal enuresis

INTRODUCTION

The pathophysiology and genetic influences in nocturnal enuresis have not been fully elucidated. Delayed neuronal maturation has been suggested as a pathogenetic mechanism in primary monosymptomatic nocturnal enuresis (PMNE). Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are neurotrophins affecting maturation of the nervous system.

OBJECTIVE

The aim of this preliminary study was to investigate BDNF and NGF gene polymorphisms and urine levels of BDNF and NGF in children with PMNE as a first time.

STUDY DESIGN

The single-nucleotide polymorphisms of BDNF (rs6265:G > A:Val66Met; rs8192466:C > T:Thr2Ile) and NGF (rs6330:C > T:Ala35Val, rs11466112:C > T:Arg221Trp) were investigated by comparing 104 children with PMNE and 140 healthy control subjects. Children with non-PMNE were excluded. DNA isolation and detection of polymorphisms were performed by real-time polymerase chain reaction. In addition, urine BDNF and NGF levels of 47 PMNE and 29 healthy children were measured by enzyme-linked immunosorbent assay method and normalized to urine creatinine (Cr) concentration for comparisons.

RESULTS

There were no differences in genotype and allele frequencies of BDNF rs6265 and NGF rs6330 polymorphisms between patients with PMNE and the control group (P > 0.05). No mutant alleles were found in BDNF rs8192466 and NGF rs11466112 polymorphisms in either group. Children with PMNE had higher urine BDNF/Cr (0.020 ± 0.010 vs 0.010 ± 0.002; P = 0.008) and NGF/Cr ratio (3.01 ± 1.87 pg/mg vs 1.77 ± 0.26 pg/mg; P = 0.002) compared with the control subjects. However, no significant differences were found in BDNF/Cr and NGF/Cr values between GG, GA, and AA genotypes of BDNF rs6265 polymorphism and CC and CT genotypes of NGF rs6330 polymorphism (P > 0.05).

DISCUSSION

In this study, no association of BDNF and NGF gene polymorphisms with PMNE was found, and urine neurotrophin concentrations were not directly influenced by investigated polymorphisms. Although, previously increased urine neurotrophin secretion has been found in detrusor overactivity, bladder inflammation, and dysfunctional voiding, this preliminary results also showed an increase in neurotrophins in PMNE. Higher urine neurotrophin levels may be related to delayed and continued neuronal maturation or increased production of neurotrophins in the bladder. The increased urine neurotrophins in PMNE may be an indicator of increased sensory nerve excitability of the bladder, contributing to the development of enuresis.

CONCLUSION

This study showed that investigated neurotrophin gene polymorphisms did not make a significant contribution to the development of PMNE, but urine levels of neurotrophin gene products were higher in PMNE. Owing to the complexity and heterogeneity of genotype-phenotype relationships in enuresis, further studies are needed in PMNE.

Primary nocturnal enuresis is associated with lower intelligence quotient scores in boys from poorer socioeconomic status families

OBJECTIVES

To explore intelligence quotient in boys with primary nocturnal enuresis compared with normal boys considering their socioeconomic status.

METHODS

A total of 152 school-aged boys (including 55 boys with primary nocturnal enuresis and 97 matched normal controls) were assessed. Boys with a history of any neurological or urological disease were excluded. Two different districts of Tehran: Khani-Abad (a poor district) and Pirouzi (a middle class district) districts were enrolled according to socioeconomic status data reported by the World Health Organization. Intelligence tests were carried out using a validated Iranian translation of the Wechsler Intelligence Scale for Children Revised. Total, as well as performance intelligence quotient and verbal intelligence quotient scores and verbal-performance discrepancy (the difference between verbal and performance intelligence quotient scores for each individual) were compared using a t-test between boys with primary nocturnal enuresis in each district and their matched controls.

RESULTS

Considering each district separately, the total intelligence quotient score was lower in primary nocturnal enuresis cases than controls only in the lower income district (90.7 ± 23.3 vs 104.8 ± 14.7, P = 0.002). Similarly, boys with primary nocturnal enuresis ranked lower in verbal intelligence quotient (P = 0.002) and performance intelligence quotient (P = 0.004) compared with their matched normal controls only in lower income district, whereas in the higher income district, boys with primary nocturnal enuresis ranked similar in total intelligence quotient to their matched controls.

CONCLUSIONS

Boys with primary nocturnal enuresis had a lower intelligence quotient compared with the control participants only in low-income district. It seems important to adjust the results of the intelligence quotient assessment in these children according to their socioeconomic status.

Abnormal Neural Responses to Emotional Stimuli but Not Go/NoGo and Stroop Tasks in Adults with a History of Childhood Nocturnal Enuresis

Background

Nocturnal enuresis (NE) is a common disorder in school-aged children. Previous studies have reported that children with NE exhibit structural, functional and neurochemical abnormalities in the brain, suggesting that children with NE may have cognitive problems. Additionally, children with NE have been shown to process emotions differently from control children. In fact, most cases of NE resolve with age. However, adults who had experienced NE during childhood may still have potential cognitive or emotion problems, and this possibility has not been thoroughly investigated.

Methodology/Principal Findings

In this work, we used functional magnetic resonance imaging (fMRI) to evaluate brain functional changes in adults with a history of NE. Two groups, consisting of 21 adults with NE and 21 healthy controls, were scanned using fMRI. We did not observe a significant abnormality in activation during the Go/NoGo and Stroop tasks in adults with a history of NE compared with the control group. However, compared to healthy subjects, young adults with a history of NE mainly showed increased activation in the bilateral temporoparietal junctions, bilateral dorsolateral prefrontal cortex, and bilateral anterior cingulate cortex while looking at negative vs. neutral pictures.

Conclusions/Significance

Our results demonstrate that adults with a history of childhood NE have no obvious deficit in response inhibition or cognitive control but showed abnormal neural responses to emotional stimuli.

Task positive and default mode networks during a working memory in children with primary monosymptomatic nocturnal enuresis and healthy controls

BACKGROUND

Nocturnal enuresis is a common developmental disorder in children, and primary monosymptomatic nocturnal enuresis (PMNE) is the dominant subtype.

METHODS

This study investigated brain functional abnormalities that are specifically related to working memory in children with PMNE using function magnetic resonance imaging (fMRI) in combination with an n-back task. Twenty children with PMNE and 20 healthy children, group-matched for age and sex, participated in this experiment.

RESULTS

Several brain regions exhibited reduced activation during the n-back task in children with PMNE, including the right precentral gyrus and the right inferior parietal lobule extending to the postcentral gyrus. Children with PMNE exhibited decreased cerebral activation in the task-positive network, increased task-related cerebral deactivation during a working memory task, and longer response times.

CONCLUSION

Patients exhibited different brain response patterns to different levels of working memory and tended to compensate by greater default mode network deactivation to sustain normal working memory function. Our results suggest that children with PMNE have potential working memory dysfunction.

Connectome-Scale Assessments of Functional Connectivity in Children with Primary Monosymptomatic Nocturnal Enuresis

Primary monosymptomatic nocturnal enuresis (PMNE) is a common developmental disorder in children. Previous literature has suggested that PMNE not only is a micturition disorder but also is characterized by cerebral structure abnormalities and dysfunction. However, the biological mechanisms underlying the disease are not thoroughly understood. Graph theoretical analysis has provided a unique tool to reveal the intrinsic attributes of the connectivity patterns of a complex network from a global perspective. Resting-state fMRI was performed in 20 children with PMNE and 20 healthy controls. Brain networks were constructed by computing Pearson's correlations for blood oxygenation level-dependent temporal fluctuations among the 2 groups, followed by graph-based network analyses. The functional brain networks in the PMNE patients were characterized by a significantly lower clustering coefficient, global and local efficiency, and higher characteristic path length compared with controls. PMNE patients also showed a reduced nodal efficiency in the bilateral calcarine sulcus, bilateral cuneus, bilateral lingual gyri, and right superior temporal gyrus. Our findings suggest that PMNE includes brain network alterations that may affect global communication and integration.

Comorbidity of ADHD and incontinence in children

ADHD and incontinence are common childhood disorders which co-occur at much higher rates than expected by chance. The aim of this review was to provide an overview both of the comorbidity of nocturnal enuresis (NE), daytime urinary incontinence (DUI) and faecal incontinence (FI) in children with ADHD; and, vice versa, of the co-occurrence of ADHD in children with NE, DUI and FI. Most clinical studies have focussed on the association of ADHD and NE. Population-based studies have shown that children with DUI have an even greater risk for ADHD than those with NE. While children with FI have the highest overall comorbidity rates of psychological disorders, these are heterogeneous with a wide range of internalising and externalising disorders--not necessarily of ADHD. Genetic studies indicate that ADHD and NE, DUI and FI do not share the same genetic basis. The comorbidity is conferred by non-genetic factors. Possible aetiological and pathogenetic links between ADHD and incontinence are provided by neurophysiological, imaging and pharmacological studies. The co-occurrence has clinical implications: children with ADHD and NE, DUI and FI are more difficult to treat, show lower compliance and have less favourable treatment outcomes for incontinence. Therefore, both groups of disorders have to be assessed and treated specifically.

Nocturnal enuresis: A topic review and institution experience

The objective is to provide a review of nocturnal enuresis (NE), including its epidemiology, etiology, pathophysiology, evaluation, and current management. We also set to provide further insight on the treatment of this condition from the experience derived from patients cared for at our tertiary-care institution. NE affects approximately 15% of all children at 5-year-old, affecting boys more frequently than girls. At our large university tertiary pediatric urology center, NE and incontinence, in general, is one the most common chief complaints prompting urologic care. In this review, we examine the condition in detail, highlighting specific goals of the initial evaluation and treatment. We contrast the commonly implemented treatment recommendations, available from the literature with strategies we have found valuable from our extensive experience in treating patients with this disorder. Using current urologic reference textbooks, book chapters, Medline, journal articles and reviews describing the many aspects of NE were reviewed in order to describe NE and the current practices at our institution. Although, this is not a systematic literature review, it includes relevant available research, institutional experience and urological expert opinion and current practices at a tertiary state health facility. The treatment of NE remains a challenge for many pediatricians and pediatric urologists. This likely stems from the multiple possible etiologies of the disorder. We have established a treatment algorithm at our institution, which we have found successful in the majority of our patients. This consists of starting patients on urotherapy, then offering both the enuresis alarm device and medication therapy as first line treatments, and finally adding anticholingerics for combination therapy. Our hope is with further research the treatment of NE will continue to improve.

Central nervous system processing of emotions in children with nocturnal enuresis and attention-deficit/hyperactivity disorder

AIM

Nocturnal enuresis (NE) and attention-deficit/hyperactivity disorder (ADHD) are common in childhood. We analysed the central processing of emotions in children with NE, ADHD, NE + ADHD and controls.

METHODS

We examined 13 children with NE, 13 with ADHD, 14 with NE + ADHD and 14 controls. Acoustic evoked potentials were recorded using standardised methodology. For the event-related potentials, positive, negative and neutral pictures were presented and time intervals of 250-450, 450-650 and 650-850 msec evaluated. Hypotheses were tested with repeated-measures analyses of variance.

RESULTS

In the frontal region, children with NE showed more intense responses to positive and negative pictures than controls measured with event-related potentials. Viewing positive pictures, children with NE + ADHD differed from children with ADHD in the central and parietal and for all types of stimuli in the parietal region. Children with NE + ADHD elicited the strongest responses. Children with ADHD did not differ from controls. There was an unspecific interaction effect of the acoustic evoked potentials in children with NE compared to the controls.

CONCLUSION

Children with NE processed emotions differently from children with ADHD and controls. Children with NE + ADHD processed emotions the most intense, displaying interaction effects of the central nervous system that cannot be explained by each disorder alone.

Brain metabolite alterations in children with primary nocturnal enuresis using proton magnetic resonance spectroscopy

Nocturnal enuresis is a common developmental disorder in children; primary monosymptomatic nocturnal enuresis (PMNE) is the dominant subtype. Previous literature has suggested that the prefrontal cortex and the pons are both involved in micturition control. This study aimed to investigate the metabolic levels of the left prefrontal cortex and the pons in children with PMNE by proton magnetic resonance spectroscopy (1H-MRS). Twenty-five children with PMNE and 25 healthy children took part in our experiments. Magnetic resonance examinations were performed on a Siemens 3T Trio Tim scanner. For each subject, localized 1H-MRS was acquired from the left prefrontal cortex (mainly in brodmann area 9) and the pons with a point-resolved spectroscopy sequence with repetition time 2,000 ms, echo time 30 ms and 64 averages. The LCModel software package was used to analyze the MRS raw data, and two-sample t tests were used to determine significant differences between the two groups. The results revealed a significant reduction in metabolite to total creatine ratios of N-acetylaspartate (NAA/tCr) in the left prefrontal cortex and the pons for children with PMNE compared to healthy children. Our study suggests that metabolism is disturbed in the prefrontal cortex and the pons in children with PMNE, which may be associated with the symptoms of enuresis.

Spontaneous brain activity changes in children with primary monosymptomatic nocturnal enuresis: a resting-state fMRI study

Primary monosymptomatic nocturnal enuresis (PMNE) is a common disorder in school-aged children. However, little is known about resting-state neural function in individuals with PMNE. In this work, resting-state functional magnetic resonance imaging (fMRI) was used to investigate changes in spontaneous brain activity in children with PMNE. We analyzed resting-state fMRI data using statistical parametric mapping (SPM) and a resting-state fMRI data analysis toolkit (REST). Regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) values were calculated to analyze spontaneous brain activity in 16 children with PMNE and 16 healthy controls. Children with PMNE exhibited significant differences in ALFF or ReHo in the left inferior frontal gyrus, medial frontal gyrus (Brodmann area, BA 10), and left midbrain. Abnormalities in BA 10 and the inferior frontal gyrus may affect children's decision-making with regard to voiding; abnormalities in the midbrain in PMNE children may influence the internal signal transmission in their bladder control network. Our data indicate that, in children with PMNE, several brain areas related to the micturate control network undergo developmental delay.

A United Kingdom population-based study of intellectual capacities in children with and without soiling, daytime wetting, and bed-wetting

OBJECTIVE

The objective of this study was to examine differences in intellectual capacities between children with and without soiling, daytime wetting, and bed-wetting.

METHODS

This study was based on a population of >6000 children (age range: 7 years 6 months to 9 years 3 months; median: 7 years 6 months) from the United Kingdom-based Avon Longitudinal Study of Parents and Children. Data on wetting and soiling were obtained from a questionnaire completed by parents. The Wechsler Intelligence Scale for Children-Third Edition was administered at a research clinic.

RESULTS

Bed-wetting was associated with lower Wechsler Intelligence Scale for Children-Third Edition IQ scores compared with control subjects, particularly performance IQ. This difference remained after exclusion of children with an IQ of <70 and adjustment for gender, stressful life events, and sociodemographic background. There were fewer differences in IQ scores between children with and without soiling or daytime wetting. Co-occurring wetting and soiling were associated with lower IQ scores than isolated soiling, daytime wetting, or bed-wetting, but this was mostly attributable to an overrepresentation of children with an IQ of <70 in the co-occurrence group.

CONCLUSIONS

It is hypothesized that the differences in intellectual capacities between children with and without bed-wetting are associated with maturational deficits of the central nervous system. There was less evidence for differences in intellectual capacities between children with and without soiling and daytime wetting. The central nervous system is involved to a lesser extent in soiling and daytime wetting, because peripheral influences from the bladder and gut play a greater role.

Relief of Nocturnal Enuresis by Desmopressin Is Kidney and Vasopressin Type 2 Receptor Independent

Primary nocturnal enuresis (PNE) is a common problem in childhood and adolescence. Although various treatments are highly effective, a common underlying hypothesis on the pathogenesis is lacking. The success of desmopressin, a synthetic analogue of the antidiuretic hormone vasopressin, has been attributed to increased renal water reabsorption that is mediated by activation of the renal vasopressin V2 receptor (V2R). However, this effect does not explain other symptoms of PNE, such as the failure to arouse upon bladder distension. This study identified a family in which one child displayed PNE and coexisting nephrogenic diabetes insipidus, as a result of a novel nonsense mutation in the V2R gene (C358X). Cell-biologic investigations revealed that V2R-C358X is retained in the endoplasmic reticulum and is unstable, which explains his nephrogenic diabetes insipidus. Consistently, extrarenal V2R-mediated responses were absent in the patient who was treated with desmopressin. Administration of desmopressin, however, changed his PNE into nocturia, because he now still voided unchanged high urinary volumes at night but woke up and went to the bathroom. Withdrawal of desmopressin was accompanied by bedwetting, whereas reintroduction again relieved the symptoms. Therefore, these data indicate that neither a functioning renal concentration system nor a functional V2R is needed for the therapeutic benefit of desmopressin in PNE. Rather, it suggests that another vasopressin receptor and other organ(s) is the target for desmopressin to relieve PNE.

Neurophysiology of nocturnal enuresis: evoked potentials and prepulse inhibition of the startle reflex

Nocturnal enuresis is a genetically determined maturational disorder of the central nervous system. Lack of arousal and an inhibition deficit of the micturition reflex have been found as the main dysfunctions leading to wetting during sleep. Both are mediated by nuclei in the brainstem. Therefore, evoked potentials (brainstem auditory evoked potential [BAEP], visual evoked potential [VEP], event-related late acoustic-evoked potential [P300]), and the prepulse inhibition (PPI) of the startle reflex were assessed to further evaluate the brainstem deficit compared with cortical function. Thirty-seven children with nocturnal enuresis, aged 8 years to 14 years 8 months (mean age 10y 7mo [SD 1y 10mo]; 27 males, 10 females) were compared with 40 controls (mean age 10y 7mo [SD 1y 6mo]; 17 males, 23 females). Left interpeak latencies I-III and I-V of the BAEP were increased in children with nocturnal enuresis. VEP measures did not differ between patients and controls. However, children with a positive family history of enuresis showed a shorter latency towards N75 and P100 than children without such a family history. P300 and PPI measures did not differ. We conclude that this strongly supports the postulation of a maturational deficit of the brainstem in nocturnal enuretic children. The increased interpeak latencies I-III and I-V of the BAEP support the hypothesis of an arousal deficit mediated by delayed maturation of brainstem function. Differences in VEP latencies might point towards functional cortical differences in children with a family history of nocturnal enuresis.

Topographic abnormalities in event-related potentials in children with monosyptomatic nocturnal enuresis

AIMS

A functional maturational delay in the central nervous system is dwelled upon in the pathogenesis of monosymptomatic nocturnal enuresis (MNE). In this study we studied whether according to controls N200 and P300, components of the event-related potential (ERP), which is related to aspects of cognitive processing, showed any difference in its topographic distribution in children within the age group 10-13 with monosymptomatic nocturnal enuresis and discussed its relation to the pathogenesis of MNE.

METHODS

We performed P300 in 18 patients with MNE and in 16 age-matched healthy subjects. P300 were evoked by an auditory oddball paradigm consisting of 150 tone bursts (80% 1 kHz; 20% 2 kHz). The latencies of the N200 and the P300 waves and the amplitude of the P300 wave were measured.

RESULTS

There was no statistical difference between the enuretic group and the controls in N200 and P300 latency and amplitude in the midline frontal (Fz), central (Cz), and parietal (Pz) recording site of the 10-20 International System. In the enuretic group while P300 amplitude in the Fz site was significantly less than the P300 amplitude in the Cz site, there was no statistical difference between the Fz and Pz P300 amplitude values.

CONCLUSIONS

When different levels of maturational delay are considered in MNE, it may be claimed that maturational delay in children whose enuresis lasts until older ages will be different from those whose enuresis ends at an early age. The determination of P300 amplitude in parietal records being less in enuretics when compared to the controls may show that there are regional differences in stimuli processing rate/quality.