Differentiation of subgroups of monosymptomatic enuresis according to prepulse inhibition of the startle reflex

Deciphering the role of brainstem glycinergic neurons during startle and prepulse inhibition

Prepulse inhibition (PPI) of the auditory startle response, a key measure of sensorimotor gating, diminishes with age and is impaired in various neurological conditions. While PPI deficits are often associated with cognitive impairments, their reversal is routinely used in experimental systems for antipsychotic drug screening. Yet, the cellular and circuit-level mechanisms of PPI remain unclear, even under non-pathological conditions. We recently showed that brainstem neurons located in the caudal pontine reticular nucleus (PnC) expressing the glycine transporter type 2 (GlyT2±) receive inputs from the central nucleus of the amygdala (CeA) and contribute to PPI but via an uncharted pathway. Here, using tract-tracing, immunohistochemistry and in vitro optogenetic manipulations coupled to field electrophysiological recordings, we reveal the neuroanatomical distribution of GlyT2± PnC neurons and PnC-projecting CeA glutamatergic neurons and we provide mechanistic insights on how these glutamatergic inputs suppress auditory neurotransmission in PnC sections. Additionally, in vivo experiments using GlyT2-Cre mice confirm that optogenetic activation of GlyT2± PnC neurons enhances PPI and is sufficient to induce PPI in young mice, emphasizing their role. However, in older mice, PPI decline is not further influenced by inhibiting GlyT2± neurons. This study highlights the importance of GlyT2± PnC neurons in PPI and underscores their diminished activity in age-related PPI decline.

Alarm interventions for nocturnal enuresis in children

BACKGROUND

Enuresis (bedwetting) affects up to 20% of five-year-olds and can have considerable social, emotional and psychological effects. Treatments include alarms (activated by urination), behavioural interventions and drugs.

OBJECTIVES

To assess the effects of enuresis alarms for treating enuresis in children.

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP, and handsearching of journals and conference proceedings (searched 25 June 2018), and reference lists of relevant articles.

SELECTION CRITERIA

We included randomised or quasi-randomised trials of enuresis alarms or alarms combined with another intervention for treating nocturnal enuresis in children between 5 and 16 years old.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias and extracted data.

MAIN RESULTS

We included 74 trials (5983 children). At treatment completion, alarms may reduce the number of wet nights a week compared to control or no treatment (mean difference (MD) -2.68, 95% confidence interval (CI) -4.59 to -0.78; 4 trials, 127 children; low-quality evidence). Low-quality evidence suggests more children may achieve complete response (14 consecutive dry nights) with alarms compared to control or no treatment (RR 7.23, 95% CI 1.40 to 37.33; 18 trials, 827 children) and that more children may remain dry post-treatment (RR 9.67, 95% CI 4.74 to 19.76; 10 trials, 366 children; low-quality evidence). At treatment completion, we are uncertain whether there is any difference between alarms and placebo drugs in the number of wet nights a week (MD -0.96, 95% CI -2.32 to 0.41; 1 trial, 47 children; very low-quality evidence). Alarms may result in more children achieving complete response than with placebo drugs (RR 1.59, 95% CI 1.16 to 2.17; 2 trials, 181 children; low-quality evidence). No trials comparing alarms to placebo reported the number of children remaining dry post-treatment. Compared with control alarms, code-word alarms probably slightly increase the number of children achieving complete response at treatment completion (RR 1.11, 95% CI 0.97 to 1.27; 1 trial, 353 children; moderate-quality evidence) but there is probably little to no difference in the number of children remaining dry post-treatment (RR 0.91, 95% CI 0.79 to 1.05; moderate-quality evidence). Very low-quality evidence means we are uncertain if there are any differences in effectiveness between the other different types of alarm. At treatment completion, alarms may reduce the number of wet nights a week compared with behavioural interventions (waking, bladder training, dry-bed training, and star chart plus rewards) (MD -0.81, 95% CI -2.01 to 0.38; low-quality evidence) and may increase the number of children achieving complete response (RR 1.77, 95% CI 0.98 to 3.19; low-quality evidence) and may slightly increase the number of children remaining dry post-treatment (RR 1.39, 95% CI 0.81 to 2.41; low-quality evidence). The evidence relating to alarms compared with desmopressin in the number of wet nights a week (MD -0.64, 95% CI -1.77 to 0.49; 4 trials, 285 children) and the number of children achieving complete response at treatment completion (RR 1.12, 95% CI 0.93 to 1.36; 12 trials, 1168 children) is low-quality, spanning possible harms and possible benefits. Alarms probably slightly increase the number of children remaining dry post-treatment compared with desmopressin (RR 1.30, 95% CI 0.92 to 1.84; 5 trials, 565 children; moderate-quality evidence). At treatment completion, we are uncertain if there is any difference between alarms and tricyclics in the number of wet nights a week, the number of children achieving complete response or the number of children remaining dry post-treatment, because the quality of evidence is very low. Due to very low-quality evidence we are uncertain about any differences in effectiveness between alarms and cognitive behavioural therapy, psychotherapy, hypnotherapy and restricted diet. Alarm plus desmopressin may reduce the number of wet nights a week compared with desmopressin monotherapy (MD -0.88, 95% CI -0.38 to -1.38; 2 trials, 156 children; low-quality evidence). Alarm plus desmopressin may increase the number of children achieving complete response (RR 1.32, 95% CI 1.08 to 1.62; 5 trials, 359 children; low-quality evidence) and the number of children remaining dry post-treatment (RR 2.33, 95% CI 1.26 to 4.29; 2 trials, 161 children; low-quality evidence) compared with desmopressin alone. Alarm plus dry-bed training may increase the number of children achieving a complete response compared to dry-bed training alone (RR 3.79, 95% CI 1.85 to 7.77; 1 trial, 80 children; low-quality evidence). It is unclear if there is any difference in the number of children remaining dry post-treatment because of the wide confidence interval (RR 0.56, 95% CI 0.15 to 2.12; low-quality evidence). Due to very low-quality evidence, we are uncertain about any differences in effectiveness between alarm plus bladder training versus bladder training alone. Of the 74 included trials, 17 reported one or more adverse events, nine reported no adverse events and 48 did not mention adverse events. Adverse events attributed to alarms included failure to wake the child, ringing without urination, waking others, causing discomfort, frightening the child and being too difficult to use. Adverse events of comparator interventions included nose bleeds, headaches and abdominal pain. There is probably a slight increase in adverse events between code-word alarm and standard alarm (RR 1.34, 95% CI 0.75 to 2.38; moderate-quality evidence), although we are uncertain because of the wide confidence interval. Alarms probably reduce the number of children experiencing adverse events compared with desmopressin (RR 0.38, 95% CI 0.20 to 0.71; 5 trials, 565 children; moderate-quality evidence). Very low-quality evidence means we cannot be certain whether the adverse event rate for alarms is lower than for other treatments.

AUTHORS' CONCLUSIONS

Alarm therapy may be more effective than no treatment in reducing enuresis in children. We are uncertain if alarm therapy is more effective than desmopressin but there is probably a lower risk of adverse events with alarms than with desmopressin. Despite the large number of trials included in this review, further adequately-powered trials with robust randomisation are still needed to determine the full effect of alarm therapy.

Changes in attention variables in those who treated with anticholinergic agents for nonmonosymptomatic enuresis

Purpose

Brain dysfunction related to areas regarding attention and arousal may occur not only in patients with attention-deficit/hyperactivity disorder (ADHD) but also in patients with enuresis and daytime symptoms. This study aimed to investigate changes in computerized comprehensive attention tests (CATs), a psychometric test for ADHD when patients with nonmonosymptomatic enuresis (NME) were treated with anticholinergic agents.

Materials and Methods

Thirty patients with NME featuring overactive bladder were prospectively enrolled. They were treated with 5 mg of solifenacin to control daytime symptoms. Using CATs, patients were evaluated during 12 weeks of treatment. Four subtests of attention (visual and auditory selective attention, sustained attention, and flanker tests) were measured. For each subtest, four domains (omission error, commission error, response time [RT], and standard deviation of RT) were assessed.

Results

Only one domain of the flanker test was in the deficient range at baseline. The presence of urge incontinence affected follow-up results on the sustained attention tests. Treatment with anticholinergic agents did not significantly affect attention variables but changes in several variables were correlated with bladder symptoms and enuresis.

Conclusions

Minimal baseline defects in attention function were seen in patients with NME. Follow-up results for some attention variables were affected by daytime symptoms and enuresis. These results suggest that altered brain function in enuretic patients influences improvement in both attention and bladder function.

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.

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.

Prepulse inhibition of acoustic startle and the influence of methylphenidate in children with ADHD

OBJECTIVE

ADHD is common among children with comorbidity of enuresis. Findings concerning prepulse inhibition (PPI) of startle reflexes are controversial. Although PPI is improved through desamino-arginine vasopressin (dDAVP) in enuresis, some patients also improve concomitant ADHD through dDAVP. This study aims to evaluate whether methylphenidate (MPH) also improves PPI in ADHD.

METHOD

Nineteen ADHD patients were investigated in a prospective, double-blind, crossover study with MPH versus placebo. PPI was measured as a reduction of acoustic startle reflexes. Subgroups of gender, ADHD subtype, and baseline PPI were analyzed.

RESULTS

Median baseline PPI of ADHD patients (51.7%) was below the value of age-matched normal controls (73%, p = .090). MPH showed no improvement in the whole group, or the subgroups gender or subtype. Reduced baseline PPI was significantly improved (22.5%-39.3%, p = .039).

CONCLUSION

Heterogeneity of ADHD is confirmed with a wide range of baseline PPI. The improvement of reduced baseline PPI through MPH suggests impaired sensorimotor gating in this subgroup.

Prepulse inhibition in psychiatric disorders--apart from schizophrenia

Prepulse inhibition (PPI) is a robust operational measure of sensorimotor gating. In schizophrenic patients PPI is deficient. The aim of our review was to investigate the state of science regarding PPI and psychiatric disorders aside from schizophrenia. We used the online database PubMed in order to search for original published reports on PPI studies. The terms "prepulse inhibition", "sensorimotor gating", "blink recovery", and "blink reflex excitability" have been combined with the names of psychiatric disorders. We found that PPI is deficient in obsessive compulsive disorder (OCD) and Gilles de la Tourette's syndrome (GTS). In bipolar disorder dysfunctional PPI seems to be rather state dependent. Studies on depression and attention deficit/hyperactivity disorder (ADHD) consistently report no alterations. Evidence regarding sensorimotor gating in anxiety, autism, fragile X syndrome, posttraumatic stress disorder (PTSD), substance disorders, and Huntington's disease is still poor. There is a strong need for further studies on PPI in psychiatric disorders. PPI is highly applicable for translational research and might also be a very useful tool to investigate the mode of action of innovative, neuro-modulative techniques. Future PPI studies should control for influencing variables such as smoking, sex, or medication.

Intensive playing leads to non-monosymptomatic enuresis in children with low prepulse inhibition

AIM

Parents of children suffering from non-monosymptomatic enuresis (nmE) report their child wetting itself during intensive playing. As children with enuresis are characterized by reduced bladder control (measured as prepulse inhibition (PPI) of startle reflex), the hypothesis suggests that intensive playing leads to further decrease in control and consecutive wetting. Two questions are important: Does PPI change while concentrating? Is this difference more explicit in children with daytime incontinence?

METHODS

Forty-four healthy children, 40 children with nmE and 37 with monosymptomatic enuresis (mE) were examined. PPI was measured while watching DVD and while playing Nintendo's Wii(®) , and calculated as percentage of the native startle response.

RESULTS

All probands showed a relevant decrease in PPI: in relaxed state, the PPI of the controls was 54%; when concentrating, it fell to 34.5% (p = 0.014). The decrease in PPI in mE was from 66% to 51% (p = 0.008), and the decrease in PPI in nmE was from 29% to 21% (p = 0.125).

CONCLUSION

While the decrease in PPI when playing was smallest in the group with nmE, overall PPI level was by far the lowest. The findings confirm the aetiology of enuresis through impaired 'sensori-motor gating' in children with nmE and provide a neurophysiologic correlate for wetting while playing.

Update: studies of prepulse inhibition of startle, with particular relevance to the pathophysiology or treatment of Tourette Syndrome

Prepulse inhibition of the startle reflex (PPI) is an operational measure of sensorimotor gating, in which the motor response to an abrupt, intense stimulus is inhibited by a weak lead stimulus. PPI is reduced in several brain disorders, including Tourette Syndrome (TS); it is regulated by forebrain circuitry, including portions of the basal ganglia implicated in the pathophysiology of TS, and is also heritable and under strong genetic control. PPI has been the focus of numerous translational models, because it is expressed by most mammalian species, with remarkable conservation of response characteristics and underlying neural circuitry between rodents and primates. Several of these models have recently explored causative factors in TS - from genes to specific basal ganglia perturbations - as well as potential TS therapeutics, including novel pharmacological and neurosurgical interventions. With the focus on Comprehensive Behavioral Interventions for Tics (CBIT) in the evolving treatment model for TS, future studies might apply PPI as a predictive measure for CBIT response, or for identifying medications that might augment CBIT efficacy. In the end, a measure based on a simple pontine-based reflex will have limitations in its ability to explicate any complex behavioral phenotype.