Design, development and validation of a new laryngo-pharyngeal endoscopic esthesiometer and range-finder based on the assessment of air-pulse variability determinants

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

Precisión de un estesiómetro endoscópico laringofaríngeo (LPEER) para evaluar la mecanosensibilidad laringofaríngea: un estudio de validación en una cohorte de pacientes reclutados prospectivamente

11 páginasRecent studies have shown an association between alterations in laryngopharyngeal mechanosensitivity (LPMS) and dysphagia, obstructive sleep apnea, and chronic cough hypersensitivity syndrome. A previous reliability study of a new laryngopharyngeal endoscopic esthesiometer and rangefinder (LPEER) showed high intra- and inter-rater reliability; however, its accuracy has not been tested. We performed an accuracy study of the LPEER in a prospectively and consecutively recruited cohort of 118 patients at two tertiary care university hospitals. Most of the patients were suffering from dysphagia, and all of them underwent a standard clinical evaluation and fiberoptic endoscopic evaluation of swallowing with sensory testing (FEESST) using a new sensory testing protocol. The sensory test included determinations of the laryngeal adductor reflex threshold (LART), the cough reflex threshold (CRT) and the gag reflex threshold (GRT). Abnormalities on these reflex thresholds were evaluated for associations with major alterations in swallowing safety (pharyngeal residues, penetration, and aspiration). We evaluated the discriminative capacity of the LPMS test using ROC curves and the area under the curve (AUC–ROC) and its relationship with the eight-point penetration–aspiration scale (PAS) using the Spearman’s ρ correlation coefficient (SCC). We found a positive correlation between the PAS and LART (SCC 0.47; P < 0.001), CRT (SCC 0.46; P < 0.001) and GRT (SCC 0.34; P = 0.002). The AUC–ROC values for detecting a PAS ≥7 were as follows: LART, 0.83 (P < 0.0001); CRT, 0.79 (P < 0.0001); GRT, 0.72 (P < 0.0001). In this study, the LPEER showed good accuracy for evaluating LPMS. These results justify further validation studies in independent populations.Estudios recientes han demostrado una asociación entre alteraciones en la mecanosensibilidad laringofaríngea (LPMS) y disfagia, apnea obstructiva del sueño y síndrome de tos hipersensibilidad crónica. Un estudio previo de confiabilidad de un nuevo estesiómetro y telémetro endoscópico laringofaríngeo (LPEER) mostró una alta confiabilidad intra e interevaluador; sin embargo, su precisión no ha sido probada. Realizamos un estudio de precisión del LPEER en una cohorte reclutada prospectiva y consecutivamente de 118 pacientes en dos hospitales universitarios de atención terciaria. La mayoría de los pacientes padecían disfagia y todos se sometieron a una evaluación clínica estándar y una evaluación endoscópica de fibra óptica de la deglución con prueba sensorial (FEESST) utilizando un nuevo protocolo de prueba sensorial. La prueba sensorial incluyó determinaciones del umbral del reflejo aductor laríngeo (LART), el umbral del reflejo de la tos (CRT) y el umbral del reflejo nauseoso (GRT). Las anomalías en estos umbrales reflejos se evaluaron en busca de asociaciones con alteraciones importantes en la seguridad de la deglución (residuos faríngeos, penetración y aspiración). Evaluamos la capacidad discriminativa del test LPMS mediante curvas ROC y el área bajo la curva (AUC-ROC) y su relación con la escala de penetración-aspiración (PAS) de ocho puntos mediante el coeficiente de correlación ρ de Spearman (SCC). Encontramos una correlación positiva entre PAS y LART (SCC 0.47; P < 0.001), CRT (SCC 0.46; P < 0.001) y GRT (SCC 0.34; P = 0.002). Los valores AUC-ROC para detectar un PAS ≥7 fueron los siguientes: LART, 0,83 (P < 0,0001); TRC, 0,79 (P < 0,0001); TRB, 0,72 (P < 0,0001). En este estudio, el LPEER mostró una buena precisión para evaluar LPMS. Estos resultados justifican más estudios de validación en poblaciones independientes