title: In vitro evaluation of the iValve: a novel hands-free speech valve.
abstract: OBJECTIVE
  We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure drops. This method makes long sentences or pauses difficult. The novel iValve is designed to allow almost natural speech, with mid-sentence pausing and whispering.
  
  
  METHODS
  The inhalation closing flows and exhalation opening pressures of 6 iValve prototype versions at different settings were compared with physiological values. The airflow resistance at inhalation was compared to physiological values and to commercial valve values.
  
  
  RESULTS
  The iValve prototypes showed flow and pressure ranges in concordance with the physiological values in the literature. The airflow resistance in the breathing mode was within the physiological airflow resistance range, yet above the values from the two commercial valves. The resistance in the speaking mode was above the physiological airflow resistance range.
  
  
  CONCLUSIONS
  In vitro tests show that the iValve versions can be selected and adjusted to operate within the physiological range. The airflow resistance in the breathing mode is good. In speaking mode, inhalation should, and can, be decreased. The iValve should offer the patient a more intuitively useable alternative with more dynamic speech. Its low cost allows disposability and wider use.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Groningen, athe Netherlands.
authors.forename: Eduard B
authors.initials: EB
authors.lastname: van der Houwen
authors.forename: Tjouwke A
authors.initials: TA
authors.lastname: van Kalkeren
authors.forename: Johannes G M
authors.initials: JG
authors.lastname: Burgerhof
authors.forename: Bernard F A M
authors.initials: BF
authors.lastname: van der Laan
authors.forename: Gijsbertus J
authors.initials: GJ
authors.lastname: Verkerke
mesh_terms: D004867:Equipment Design; D006801:Humans; D007825:Laryngectomy / Q000534:rehabilitation*; D007831:Larynx, Artificial; D008422:Materials Testing; D011312:Pressure; D013071:Speech, Alaryngeal / Q000295:instrumentation; D014139:Tracheostomy / Q000295:instrumentation