title: Design, development and validation of a new laryngo-pharyngeal endoscopic esthesiometer and range-finder based on the assessment of air-pulse variability determinants.
abstract: BACKGROUND
  Laryngo-pharyngeal mechano-sensitivity (LPMS) is involved in dysphagia, sleep apnea, stroke, irritable larynx syndrome and cough hypersensitivity syndrome among other disorders. These conditions are associated with a wide range of airway reflex abnormalities. However, the current device for exploring LPMS is limited because it assesses only the laryngeal adductor reflex during fiber-optic endoscopic evaluations of swallowing and requires a high degree of expertise to obtain reliable results, introducing intrinsic expert variability and subjectivity.
  
  
  METHODS
  We designed, developed and validated a new air-pulse laryngo-pharyngeal endoscopic esthesiometer with a built-in laser range-finder (LPEER) based on the evaluation and control of air-pulse variability determinants and on intrinsic observer variability and subjectivity determinants of the distance, angle and site of stimulus impact. The LPEER was designed to be capable of delivering precise and accurate stimuli with a wide range of intensities that can explore most laryngo-pharyngeal reflexes.
  
  
  RESULTS
  We initially explored the potential factors affecting the reliability of LPMS tests and included these factors in a multiple linear regression model. The following factors significantly affected the precision and accuracy of the test (P < 0.001): the tube conducting the air-pulses, the supply pressure of the system, the duration of the air-pulses, and the distance and angle between the end of the tube conducting the air-pulses and the site of impact. To control all of these factors, an LPEER consisting of an air-pulse generator and an endoscopic laser range-finder was designed and manufactured. We assessed the precision and accuracy of the LPEER's stimulus and range-finder according to the coefficient of variation (CV) and by looking at the differences between the measured properties and the desired values, and we performed a pilot validation on ten human subjects. The air-pulses and range-finder exhibited good precision and accuracy (CV < 0.06), with differences between the desired and measured properties at <3 % and a range-finder measurement error of <1 mm. The tests in patients demonstrated obtainable and reproducible thresholds for the laryngeal adductor, cough and gag reflexes.
  
  
  CONCLUSIONS
  The new LPEER was capable of delivering precise and accurate stimuli for exploring laryngo-pharyngeal reflexes.
authors.affiliation: School of Medicine, University of Navarra, Irunlarea 1, 31080, Pamplona, Navarra, Spain. lgiraldo@alumni.unav.es.|School of Medicine, University of La Sabana, Autonorte de Bogotá, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia. lgiraldo@alumni.unav.es.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Giraldo-Cadavid
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Luis Mauricio
authors.initials: LM
authors.lastname: Agudelo-Otalora
authors.affiliation: School of Sciences, University of Navarra, Irunlarea 1, 31080, Pamplona, Navarra, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Burguete
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Mario
authors.initials: M
authors.lastname: Arbulu
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: William Daniel
authors.initials: WD
authors.lastname: Moscoso
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Fabio
authors.initials: F
authors.lastname: Martínez
authors.affiliation: Statistical Consulting Office, University of Santo Tomas, Carrera 9 # 51-11, Bogota, Colombia.
authors.forename: Andrés Felipe
authors.initials: AF
authors.lastname: Ortiz
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Juan
authors.initials: J
authors.lastname: Diaz
authors.affiliation: Departamento de Medicina Interna, School of Medicine, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Comun, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Pantoja
authors.affiliation: School of Engineering, University of La Sabana, Autonorte de Bogota, Km 7, Campus Puente del Común, Chia, 250001, Cundinamarca, Colombia.
authors.forename: Andrés Felipe
authors.initials: AF
authors.lastname: Rueda-Arango
authors.affiliation: School of Medicine, University of Navarra, Irunlarea 1, 31080, Pamplona, Navarra, Spain.
authors.forename: Secundino
authors.initials: S
authors.lastname: Fernández
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000388:Air; D004724:Endoscopy / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007830:Larynx / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000502:physiology; D011312:Pressure; D012018:Reflex; D012677:Sensation
keywords: Accuracy; Airway; Biomedical engineering; Biomedical equipment; Biomedical imaging; Bronchoscopy; Calibration; Deglutition; Endoscopes; Esthesiometer; Fiber lasers; Larynx; Mechanoreceptor; Medical diagnosis; Optical fibers; Pharynx; Range finder; Reflex; Reliability; Repeatability and reproducibility of results; Sensory thresholds; Telemeter