Blue blocker glasses as a countermeasure for alerting effects of evening LED - screen exposure in teenagers

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Lower urinary tract electrical sensory assessment: A systematic review and meta-analysis

OBJECTIVE To summarize the current literature on lower urinary tract electrical sensory assessment (LUTESA), with regard to current perception thresholds (CPTs) and sensory evoked potentials (SEPs). The applied methods will be discussed in terms of technical aspects, confounding factors, and potential for lower urinary tract (LUT) diagnostics. METHODS The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline (PubMed), Embase and Scopus were searched upon October 13, 2020. Meta-analyses were performed and methodological qualities of the included studies were defined by assessing risk-of-bias (RoB) as well as confounding. RESULTS After screening 9925 articles, 80 studies (5 randomized controlled trials (RCTs) and 75 non-RCTs) were included, comprising a total of 3732 patients and 692 healthy subjects. 61 studies investigated exclusively CPTs and 19 studies reported on SEPs, with or without corresponding CPTs. The recording of LUTCPTs and -SEPs was shown to represent a safe and reliable assessment of LUT afferent nerve function in healthy subjects and patients. LUTESA demonstrated significant differences in LUT sensitivity between healthy subjects and neurological patients as well as after interventions such as pelvic surgery or drug treatments. Pooled analyses revealed that several stimulation parameters (e.g. stimulation frequency, location) as well as patient characteristics might affect the main outcome measures of LUTESA (CPTs, SEP latencies, peak-to-peak amplitudes, responder rate). RoB and confounding was high in most studies. CONCLUSIONS Preliminary data show that CPT and SEP recordings are valuable tools to more objectively assess LUT afferent nerve function. LUTESA complement already established diagnostics such as urodynamics, allowing for a more comprehensive patient workup. The high RoB and confounding rate was rather related to inconsistency and inaccuracy in reporting than the technique itself. LUTESA standardization and well-designed RCTs are crucial to implement LUTESA as a clinical assessment tool

Development of a Sham Protocol to Investigate Transcutaneous Tibial Nerve Stimulation in Randomised, Sham-Controlled, Double-Blind Clinical Trials

Transcutaneous tibial nerve stimulation (TTNS) is a promising treatment for neurogenic lower urinary tract symptoms. However, the evidence is limited due to a general lack of randomised controlled trials (RCTs) and, also, inconsistency in the sham and blinding conditions. In the context of much-needed RCTs, we aimed to develop a suitable sham-control protocol for a clinical setting to maintain blinding but avoid meaningful stimulation of the tibial nerve. Three potential electrode positions (lateral malleolus/5th metatarsal/plantar calcaneus) and two electrode sizes (diameter: 2.5 cm/3.2 cm) were tested to determine which combination provided the optimal sham configuration for a TTNS approach, based on a visible motor response. Sixteen healthy volunteers underwent sensory and motor assessments for each sham configuration. Eight out of them came back for an extra TTNS visit. Sensory thresholds were present for all sham configurations, with linear regression models revealing a significant effect regarding electrode position (highest at plantar calcaneus) but not size. In addition, motor thresholds varied with the position-lowest for the 5th metatarsal. Only using this position and 3.2 cm electrodes attained a 100% response rate. Compared to TTNS, sensory and motor thresholds were generally higher for the sham configurations; meanwhile, perceived pain was only higher at the lateral malleolus. In conclusion, using the 5th metatarsal position and 3.2 cm electrodes proved to be the most suitable sham configuration. Implemented as a four-electrode setup with standardized procedures, this appears to be a suitable RCT protocol for maintaining blinding and controlling for nonspecific TTNS effects in a clinical setting

bTUNED: transcutaneous tibial nerve stimulation for neurogenic lower urinary tract dysfunction

OBJECTIVE To present the protocol for a randomized controlled trial (RCT) evaluating the efficacy and safety of transcutaneous tibial nerve stimulation (TTNS) for refractory neurogenic lower urinary tract dysfunction (NLUTD). STUDY DESIGN AND RESULTS bTUNED (bladder and TranscUtaneous tibial Nerve stimulation for nEurogenic lower urinary tract Dysfunction) is an international multicentre, sham-controlled, double-blind RCT investigating the efficacy and safety of TTNS. The primary outcome is success of TTNS, defined as improvements in key bladder diary variables at study end compared to baseline values. The focus of the treatment is defined by the Self-Assessment Goal Achievement (SAGA) questionnaire. Secondary outcomes are the effect of TTNS on urodynamic, neurophysiological, and bowel function outcome measures, as well as the safety of TTNS. CONCLUSIONS A total of 240 patients with refractory NLUTD will be included and randomized 1:1 into the verum or sham TTNS group from March 2020 until August 2026. TTNS will be performed twice a week for 30 min during 6 weeks. The patients will attend baseline assessments, 12 treatment visits and follow-up assessments at the study end

Scalp Topography of Lower Urinary Tract Sensory Evoked Potentials

Impaired lower urinary tract (LUT) afferents often cause LUT symptoms. Assessment of LUT afferent pathways is possible using bipolar cortical sensory evoked potential (SEP) recordings with the active electrode at the vertex during electrical stimulation in the LUT. This study aimed to investigate the topographical distribution and microstates of lower urinary tract sensory evoked potentials (LUTSEPs) using different stimulation frequencies. Ninety healthy subjects (18-36 years old, 40 women) were randomly assigned to one of five stimulation locations [bladder dome; trigone; proximal, membranous (men only) or distal urethra]. Cycles of 0.5 Hz/1.1 Hz/1.6 Hz electrical stimulation were applied using a custom-made catheter. Cortical activity was recorded from 64 surface electrodes. Marker setting was performed manually on an individual subject-level for the P1, N1, and P2 components of vertex recordings. N1 and P2 topographies presented with central negativities and positivities around the vertex. Regarding topographical distribution, Randomization Graphical User interface (RAGU) analyses revealed consistent frequency effects and microstates for N1/P2. Higher stimulation frequencies resulted in decreasing map strength for P1, N1, and P2. LUTSEP topographies suggest central generators in the somatosensory cortex, which are not detectable in a bipolar set-up. The observed frequency effect indicates fiber refractoriness at higher frequencies. The multichannel approach allows more comprehensive assessment of LUTSEPs and might therefore be sensitive to pathological changes. Examinations in patients with LUT symptoms are needed to further investigate this biomarker

Neuroimaging in Neuro-Urology

Neuroimaging allows in vivo visualization of neuronal structures/processes to assess their involvement in bodily functions. This is particularly valuable for the assessment of complex, multilevel neuronal controlled functions, such as urine storage and micturition. Using positron emission tomography or functional magnetic resonance imaging, significant alterations of supraspinal lower urinary tract (LUT) control have been described in patients with neurogenic LUT dysfunction due to spinal cord injury, Parkinson's disease, and multiple sclerosis. Severity of such alterations often correlates with symptom/dysfunction severity, both of which could be partly mitigated by therapeutic interventions. However, the overall evidence and study quality are presently very limited, and a multidisciplinary approach will be required to achieve clinical relevance in the long term. PATIENT SUMMARY: We reviewed the findings of neuroimaging studies in patients with bladder dysfunction due to neurological trauma/disease. Changes in the nervous systems of these patients alter bladder control, and neuroimaging may become a valuable tool for assessing these alterations

Quantitative electrical pain threshold assessment in the lower urinary tract

AIMS Assessing the reliability of electrical pain threshold (PT) and evaluating the impact of stimulation frequency at different locations in the healthy lower urinary tract (LUT). METHODS Ninety subjects (age: 18.3-35.8 years, 40 females, 50 males) were randomly allocated to one stimulation site (bladder dome [BD], trigone, proximal, membranous (only males), or distal urethra). Using 0.5 Hz/1.1 Hz/1.6 Hz electrical stimulation (square wave, pulse width:1 ms), current perception thresholds (CPTs), PTs and tolerance thresholds were assessed at two visits. Analyses were performed using linear mixed models, intraclass correlation coefficients (ICC) and Bland-Altman method. RESULTS PTs vary in relation to stimulation frequency, location and between genders. PT decreased with higher stimulation frequency. The highest PTs were measured at the BD and membranous urethra with males reporting higher PTs than females. Reliability of PT assessments according to ICC was good to excellent across all frequencies, locations, and genders (ICC = 0.61-0.97), except for BD and distal urethra in females showing poor to fair reliability (BD: all frequencies, distal urethra: 0.5 Hz). CONCLUSIONS PTs can be safely and reliably assessed from bladder and urethral locations. Semi-objective PT assessment may provide additional information on functionality and sensitivity of the LUT slow fiber afferents and complement findings from urodynamic investigations and CPT assessments. In conclusion, the developed methodology may open new opportunities for using electrical stimulation paradigms for LUT PT assessments and diagnostics. All this allows a more precise, location-specific characterization of pain origin and pain reaction towards therapy

Does electrical stimulation in the lower urinary tract increase urine production? A randomised comparative proof-of-concept study in healthy volunteers

TRIAL DESIGN During electrical stimulation in the lower urinary tract for the purpose of current perception threshold and sensory evoked potential recording, we observed that bladder volume increased rapidly. The aim of this prospective randomised comparative proof-of-concept study was to quantify urine production per time during stimulation of the lower urinary tract using different stimulation frequencies. METHODS Ninety healthy subjects (18 to 36 years old) were included. Forty females and 50 males were randomly assigned to one of the following study groups: dome, trigone or proximal, membranous (males only) or distal urethra. Starting from 60mL prefilling, stimulation was performed at two separate visits with a 14 French custom-made catheter using randomly applied frequencies of 0.5Hz, 1.1Hz, 1.6Hz (each with 500 stimuli). After each stimulation cycle per frequency, urine production was assessed. Main outcome measures represented urine production during stimulation, daily life and their ratio. RESULTS Lower urinary tract electrical stimulation increased urine production per time compared to bladder diary baseline values. Linear mixed model showed that frequency (p<0.001), stimulation order (p = 0.003), intensity (p = 0.042), and gender (p = 0.047) had a significant influence on urine production. Location, visit and age had no significant influence. CONCLUSIONS Urine production is increased during electrical stimulation with a bigger impact of higher frequencies. This might be relevant for methodological aspects in the assessment of lower urinary tract afferent function and for patients with impaired renal urine output. Inhibition of renal sympathetic nerve activity by vagal afferents may be the underlying mechanism

Transcutaneous Tibial Nerve Stimulation for Treating Neurogenic Lower Urinary Tract Dysfunction: A Pilot Study for an International Multicenter Randomized Controlled Trial

BACKGROUND Tibial nerve stimulation (TNS) is an effective and safe treatment for idiopathic lower urinary tract dysfunction (LUTD), but its value in neurological patients is unclear. OBJECTIVE To test the feasibility, acceptability, and safety of a randomized, sham-controlled, double-blind transcutaneous TNS (TTNS) setup for treating neurogenic LUTD. DESIGN, SETTING, AND PARTICIPANTS A pilot study including nine patients with refractory neurogenic LUTD investigated prospectively at a university neuro-urology department. INTERVENTION Randomized, sham-controlled, double-blind verum and sham TTNS was performed for 30min twice a week, for 6 wks. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Outcomes were feasibility, acceptability, and safety of the TTNS protocol. Secondarily, potential efficacy was investigated. Descriptive statistics were used. RESULTS AND LIMITATIONS All procedures were feasible and well tolerated by all nine patients. Using verum TTNS, a motor response could be triggered in all patients and a sensory response in all but one. At the beginning and end of treatment, seven and six (78% and 67%) patients believed to receive verum TTNS, and five and six (56% and 67%) correctly guessed their group allocation, respectively. No treatment-related adverse events occurred. A comparison of baseline versus 6 wks of verum and sham TTNS led to relevant symptom and functional changes in only a limited number of piloted patients. CONCLUSIONS Verum and sham TTNS combined with the blinding procedures proved feasible and safe. Both interventions and procedures, as well as the randomization process, were well accepted by the patients. While the subsensory threshold TTNS approach in combination with the sham condition is advantageous for patients' blinding, the clinical findings raised some doubt regarding sufficient TNS. Hence, relevant methodological adjustments concerning the adequate stimulation current and corresponding sham condition are needed before starting randomized controlled trials to clarify the value and role of TTNS in neuro-urology. PATIENT SUMMARY Transcutaneous tibial nerve stimulation is a promising treatment option for neurogenic lower urinary tract dysfunction, but methodological adjustments in treatment application are required before further prospective studies can be initiated