title: Non-invasive characterization of real-time bladder sensation using accelerated hydration and a novel sensation meter: An initial experience.
abstract: OBJECTIVE
  The purpose of this investigation was to develop a non-invasive, objective, and unprompted method to characterize real-time bladder sensation.
  
  
  METHODS
  Volunteers with and without overactive bladder (OAB) were prospectively enrolled in a preliminary accelerated hydration study. Participants drank 2L Gatorade-G2® and recorded real-time sensation (0-100% scale) and standardized verbal sensory thresholds using a novel, touch-screen "sensation meter." 3D bladder ultrasound images were recorded throughout fillings for a subset of participants. Sensation data were recorded for two consecutive complete fill-void cycles.
  
  
  RESULTS
  Data from 14 normal and 12 OAB participants were obtained (ICIq-OAB-5a = 0 vs. ≥3). Filling duration decreased in fill2 compared to fill1, but volume did not significantly change. In normals, adjacent verbal sensory thresholds (within fill) showed no overlap, and identical thresholds (between fill) were similar, demonstrating effective differentiation between degrees of %bladder capacity. In OAB, within-fill overlaps and between-fill differences were identified. Real-time %capacity-sensation curves left shifted from fill1 to fill2 in normals, consistent with expected viscoelastic behavior, but unexpectedly right shifted in OAB. 3D ultrasound volume data showed that fill rates started slowly and ramped up with variable end points.
  
  
  CONCLUSIONS
  This study establishes a non-invasive means to evaluate real-time bladder sensation using a two-fill accelerated hydration protocol and a sensation meter. Verbal thresholds were inconsistent in OAB, and the right shift in OAB %capacity-sensation curve suggests potential biomechanical and/or sensitization changes. This methodology could be used to gain valuable information on different forms of OAB in a completely non-invasive way.
authors.affiliation: Department of Mechanical & Nuclear Engineering, Virginia Commonwealth University School of Engineering, Richmond, Virginia.
authors.forename: Anna S
authors.initials: AS
authors.lastname: Nagle
authors.affiliation: Department of Mechanical & Nuclear Engineering, Virginia Commonwealth University School of Engineering, Richmond, Virginia.
authors.forename: John E
authors.initials: JE
authors.lastname: Speich
authors.affiliation: Department of Urology, University Hospital Antwerpen, Edegem, University of Antwerpen, Wilrijk, Belgium.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: De Wachter
authors.affiliation: Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.
authors.forename: Peter P
authors.initials: PP
authors.lastname: Ghamarian
authors.affiliation: Department of Biomedical Engineering, Virginia Commonwealth University School of Engineering, Richmond, Virginia.
authors.forename: David M
authors.initials: DM
authors.lastname: Le
authors.affiliation: Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Colhoun
authors.affiliation: Department of Biochemistry & Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Ratz
authors.affiliation: Department of Emergency Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Barbee
authors.affiliation: Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.|Department of Surgery/Division of Urology Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Klausner
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012677:Sensation / Q000502:physiology*; D014463:Ultrasonography; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000502:physiology*; D014554:Urination / Q000502:physiology*; D014563:Urodynamics / Q000502:physiology*; D055815:Young Adult
keywords: 3D ultrasound; non-invasive urgency characterization; perception of bladder fullness; urinary urgency; variable fill rate; verbal sensory thresholds