Degree of urge, perception of bladder fullness and bladder volume--how are they related?

Bladder Volume Monitoring Using Electrical Impedance Tomography With Simultaneous Multi-Tone Tissue Stimulation and DFT-Based Impedance Calculation Inside an FPGA

In this article, a novel method for measuring the volume of the urinary bladder non-invasively is presented that relies on the principles dictated by Electrical Impedance Tomography (EIT). The electronic prototype responsible for injecting innocuous electrical currents to the lower abdominal region and measuring the developed voltage levels is fully described, as well as the computational models for resolution of the so-called Forward and Inverse Problems in Imaging. The simultaneous multi-tone injection of current provided by a high performance Field Programmable Gate Array (FPGA), combined with impedance estimation by the Discrete Fourier Transform (DFT) constitutes a novelty in Urodynamics with potential to monitor continuously the intravesical volume of patients in a much faster and comfortable way than traditional transurethral catheterization methods. The resolution of the Inverse Problem is performed by the Gauss-Newton method with Laplacian regularization, allowing to obtain a sectional representation of the volume of urine encompassed by the bladder and surrounding body tissues. Experimentation has been carried out with synthetic phantoms and human subjects with results showing a good correlation between the levels of abdominal admittivity acquired by the EIT system and the volume of ingested water.

Bladder sensations in male and female overactive bladder patients compared to healthy volunteers: a sensation-related bladder diary evaluation

Objectives: To investigate the differences in bladder sensations of overactive bladder (OAB) patients compared to healthy volunteers. In addition, to see if bladder sensations are different in men and women.Methods: In a prospective, longitudinal study (METC 09-2-095), 66 volunteers and 68 OAB patients were included. Anticholinergic medication was stopped. Subjects filled out a sensation-related bladder diary (SR-BD), for two periods of 3 days, including a 4-points urgency scale and visual analogue scale for perception of bladder fullness.Results: In total, 6160 voids were assessed. Patients voided more often with higher degrees of urge at a lower mean voided volume (193 vs 270 ml/void; p < 0.001) than healthy volunteers. The mean urinary frequency per litre diuresis was also higher (5.8 vs 4.1/l; p < 0.001) in patients. At the same voided volume: patients perceived a higher mean bladder fullness, independent of the degree of urge, and higher urgency (1.4 vs 0.5/100 ml; p < 0.001) than healthy volunteers. There were no gender differences in the above-mentioned voiding parameters, except for the mean voided volume at urge 3 in volunteers (340 ml in men vs 362 ml in women; p = 0.03) and urge 1 in patients (171 ml in men vs 135 ml in women; p = 0.027).Conclusions: Bladder sensations were significantly increased in everyday life for both male and female OAB patients compared to healthy volunteers. OAB patients experienced a higher mean bladder fullness sensation, independent of the degree of urge, and higher mean urge/urgency at the same voided volume than volunteers. Bladder sensations are crucial in the assessment of treatment response.

Methods of assessing and recording bladder sensation: a review of the literature

Introduction and hypothesis

The objective was to review different methods that have been used to assess bladder sensation and to provide an overview of the accuracy and objectivity of the measurement of the subjective perception of the bladder.

Methods

The MEDLINE and PubMed databases were searched to identify articles. References from those articles were also searched. Terms used for the search were: urinary bladder, sensation, cystometry, urodynamics, urinary incontinence and focus group. Eight hundred and fifty abstracts were identified from databases, and 12 from other sources. Twenty-two duplicate articles were removed. Irrelevant articles were excluded after reading their titles. Fifty-four articles were eligible, but 17 were excluded after reading the full text, leaving 37 articles where assessment of bladder sensation was the main aim.

Results

Six different methods of measuring bladder sensation have been described in the literature. Although the most frequently used was cystometry, this is an invasive tool and does not reproduce bladder behaviour during daily life because it records bladder sensation as episodic events. The visual analogue scale using a forced diuresis protocol seemed to be an excellent tool. It was non-invasive and evaluated bladder sensation continuously, from an empty to a full bladder.

Conclusions

In some of the studies, the samples were too small to draw any significant conclusions. There were also conflicting data on which tool was the most accurate, especially as each method of evaluating bladder sensation may influence the way it is described by participants.

Validation of a water-load protocol to define the pattern of bladder sensation

Introduction and hypothesis

The aim of this study was to confirm reliability of a water-load diuresis protocol and to assess the utility of bladder sensation curves.

Methods

For confirmation of fixed diuresis rate (phase 1), 12 volunteers consumed 250–300 ml of water every 15 min and recorded bladder sensation on a visual analogue scale (VAS) every 5 min to maximum sensation over two filling cycles: voids 1 and 2 (V1 and V2). The test was performed twice. For test–retest validation (phase 2), 24 participants underwent the same protocol drinking 300 ml of water every 15 min. Diuresis rates and voided volumes were compared between cycles and across tests.

Results

In phase 1, there was no difference in median void volume (V1 735 ml, V2 678 ml p = 0.433) or median diuresis rates (V2 12.1 ml/min, V3 14.4 ml/min p = 0.136) between cycles. When comparing those who drank 250–300 ml/15 min, there was less variability in those drinking 300-ml aliquots, so this was standardised for later experiments; 95% upper confidence limit of variability of the diuresis rate was calculated as 4.5 ml/min. Any test with a greater difference was rejected as invalid. In phase 2, only 16 participants were analysed. There was no difference in median void volumes between tests [V1 763 ml and 820 ml (p = 0.109) and V2 788 ml and 796 ml (p = 0.266)] or in diuresis rates between test 1 (12.33 ml/min) and 2 (14.40 ml/min) (p = 0.056). Median area under the curve was similar between test 1 404.96 and test 2 418.63.

Conclusions

This refined protocol reliably produced stable diuresis with a water load of 300 ml/15 min, excluding those with a difference in diuresis rate > 4.5 ml/min.

Protocol for a prospective, randomized study on neurophysiological assessment of lower urinary tract function in a healthy cohort

Background

Lower urinary tract symptoms are highly prevalent and a large proportion of these symptoms are known to be associated with a dysfunction of the afferent pathways. Diagnostic tools for an objective and reproducible assessment of afferent nerve function of the lower urinary tract are missing. Previous studies showed first feasibility results of sensory evoked potential recordings following electrical stimulation of the lower urinary tract in healthy subjects and patients. Nevertheless, a refinement of the methodology is necessary.

Methods

This study is a prospective, randomized trial conducted at Balgrist University Hospital, Zürich, Switzerland. Ninety healthy subjects (forty females and fifty males) without lower urinary tract symptoms are planned to be included in the study. All subjects will undergo a screening visit (including standardized questionnaires, 3-day bladder diary, urinalysis, medical history taking, vital signs, physical examination, neuro-urological examination) followed by two measurement visits separated by an interval of 3 to 4 weeks. Electrical stimulations (0.5Hz-5Hz, bipolar, square wave, pulse width 1 ms) will be applied using a custom-made transurethral catheter at different locations of the lower urinary tract including bladder dome, trigone, proximal urethra, membranous urethra and distal urethra. Every subject will be randomly stimulated at one specific site of the lower urinary tract. Sensory evoked potentials (SEP) will be recorded using a 64-channel EEG cap. For an SEP segmental work-up we will place additional electrodes on the scalp (Cpz) and above the spine (C2 and L1). Visit two and three will be conducted identically for reliability assessment.

Discussion

The measurement of lower urinary tract SEPs elicited by electrical stimulation at different locations of the lower urinary tract has the potential to serve as a neurophysiological biomarker for lower urinary tract afferent nerve function in patients with lower urinary tract symptoms or disorders. For implementation of such a diagnostic tool into clinical practice, an optimized setup with efficient and reliable measurements and data acquisition is crucial. In addition, normative data from a larger cohort of healthy subjects would provide information on variability, potential confounding factors and cut-off values for investigations in patients with lower urinary tract dysfunction/symptoms.

Trial registration

Clinicaltrials.gov; Identifier: NCT02272309.

Can Interoception Improve the Pragmatic Search for Biomarkers in Psychiatry?

Disrupted interoception is a prominent feature of the diagnostic classification of several psychiatric disorders. However, progress in understanding the interoceptive basis of these disorders has been incremental, and the application of interoception in clinical treatment is currently limited to panic disorder. To examine the degree to which the scientific community has recognized interoception as a construct of interest, we identified and individually screened all articles published in the English language on interoception and associated root terms in Pubmed, Psychinfo, and ISI Web of Knowledge. This search revealed that interoception is a multifaceted process that is being increasingly studied within the fields of psychiatry, psychology, neuroscience, and biomedical science. To illustrate the multifaceted nature of interoception, we provide a focused review of one of the most commonly studied interoceptive channels, the cardiovascular system, and give a detailed comparison of the most popular methods used to study cardiac interoception. We subsequently review evidence of interoceptive dysfunction in panic disorder, depression, somatic symptom disorders, anorexia nervosa, and bulimia nervosa. For each disorder, we suggest how interoceptive predictions constructed by the brain may erroneously bias individuals to express key symptoms and behaviors, and outline questions that are suitable for the development of neuroscience-based mental health interventions. We conclude that interoception represents a viable avenue for clinical and translational research in psychiatry, with a well-established conceptual framework, a neural basis, measurable biomarkers, interdisciplinary appeal, and transdiagnostic targets for understanding and improving mental health outcomes.

The effect of bladder sensation on uroflowmetry parameters in healthy young men

AIMS

To investigate the effect of the bladder sensation grade on uroflowmetry parameters.

METHODS

Fifty healthy volunteering young men were enrolled in the present study. In total, three uroflowmetry evaluations were made. Qmax , Qave , VV, and PVR urine was obtained three times in three described bladder sensation grades, nearly at the same time of the day.

RESULTS

The mean age of the participants in the present study is 29.08 ± 3.8 years. The mean Qmax values of the volunteers were 17.4 ± 4.8 ml/s, 24.1 ± 6.0 ml/s, and 29.6 ± 6.5 ml/s in the first, second, and third, voiding desire grades, respectively. The mean Qave values were 9.9 ± 2.1 ml/s, 12.9 ± 2.9 ml/s, and 15.9 ± 4.0 ml/s for each of the voiding desire grades mentioned. A statistically significant difference was obvious for all three bladder sensation grades in terms of Qmax and Qave values (P = 0.000). However, no statistically significant difference was seen regarding the PVR urine volumes. The mean voided volume in the first, second and third uroflowmetry were 140 ± 42 ml, 245 ± 64 ml, and 449 ± 105 ml, respectively. The highest Qmax and Qave values were obtained when the desire to void was urgent.

CONCLUSIONS

The findings of the study show that, uroflowmetry evaluations are to be made if the patients have a strong desire to void. Only thus the highest Qmax values can be obtained; yet, the degree of perceived bladder sensation does not have a statistically significant impact on PVR quantity. Neurourol. Urodynam. 35:622-624, 2016. © 2015 Wiley Periodicals, Inc.

Validating of a Novel Method for Electronically Recording Overactive Bladder Symptoms in Men

OBJECTIVE

The goal of this study was to compare a novel wireless phone and web based technology to record and store overactive bladder symptoms (OAB-S) to a traditional pen and paper micturition chart.

METHODS

Overactive bladder symptoms were recorded over a period of 3 days using both an electronic micturition chart (EMC) and the standard pen and paper micturition chart (MC). Twenty-nine men, with lower urinary tract symptoms (LUTS), were included in the study. Dropout rate, patient's preference, and correlation between the quality of life measures (QoL) and symptoms recorded with EMC versus MC, were assessed and compared.

RESULTS

Of the total number of 29 patients enrolled into the study, 24 completed the full 3-day trial using MC and 27 using EMC. MC was preferred by 50%, while EMC was preferred by 50% of participants. Using MC, 21% of patients forgot to record at least one episode of urgency, versus 17% using EMC, 17% forgot to record at least one micturition using MC versus 8% using EMC. A statistically significant correlation was found between lower severity of OAB-S and higher QoL, using both recording methods.

CONCLUSIONS

In this study population, recording symptoms with EMC did not prove to be preferable compared to MC; however, EMC provided the same level of accuracy with the same or better adherence to the study protocol.

Comparison of the overactive bladder symptom score and the overactive bladder symptom score derived from the bladder diaries

AIMS

The overactive bladder symptom score (OABSS) is a useful tool for assessing the four key symptoms of overactive bladder (OAB), but it sometimes misrepresents a patient's actual voiding status. To examine whether the patient-determined OABSS underestimates or overestimates the true status, its results were compared to those of the OABSS derived from a 7-day bladder diary (OABSS-BD).

METHODS

Records of patients who visited our outpatient clinic with lower urinary tract symptoms were evaluated retrospectively. The patients were asked to complete the OABSS and the 7-day bladder diary (BD). The OABSS-BD was created from the 7-day BD. Questions were compared between the OABSS and the OABSS-BD.

RESULTS

A total of 44 men and 31 women were evaluated. For daytime frequency, the mean OABSS score was 1.03 ± 0.57 and the OABSS-BD score was 0.69 ± 0.52 (P < 0.01). For nighttime frequency, the mean OABSS score was 2.27 ± 0.84, and the OABSS-BD score was 1.96 ± 1.00 (P = 0.04). For urinary urgency, the mean OABSS score was 2.49 ± 1.83, and the OABSS-BD score was 2.70 ± 1.90 (P = 0.27). For urgency incontinence, the mean OABSS score was 1.67 ± 1.92, and the OABSS-BD score was 1.52 ± 1.87 (P = 0.28). For the total score, the mean OABSS total score was 7.26 ± 3.92, and the OABSS-BD score was 6.98 ± 3.26 (P = 0.23).

CONCLUSIONS

The OABSS is a very simple and useful tool. However, compared to the results from the 7-day FVC, the present patients overestimated daytime and nighttime frequency.