Intraobserver and Interobserver Reliability in Laryngopharyngeal Sensory Discrimination Thresholds: A Pilot Study

Relationship between post-stroke dysphagia and pharyngeal sensory impairment

BACKGROUND

Post-stroke dysphagia (PSD) is common and can lead to serious complications. Pharyngeal sensory impairment is assumed to contribute to PSD. The aim of this study was to investigate the relationship between PSD and pharyngeal hypesthesia and to compare different assessment methods for pharyngeal sensation.

METHODS

In this prospective observational study, fifty-seven stroke patients were examined in the acute stage of the disease using Flexible Endoscopic Evaluation of Swallowing (FEES). The Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS) and impaired secretion management according to the Murray-Secretion Scale were determined, as well as premature bolus spillage, pharyngeal residue and delayed or absent swallowing reflex. A multimodal sensory assessment was performed, including touch-technique and a previously established FEES-based swallowing provocation test with different volumes of liquid to determine the latency of swallowing response (FEES-LSR-Test). Predictors of FEDSS, Murray-Secretion Scale, premature bolus spillage, pharyngeal residue, and delayed or absent swallowing reflex were examined with ordinal logistic regression analyses.

RESULTS

Sensory impairment using the touch-technique and the FEES-LSR-Test were independent predictors of higher FEDSS, Murray-Secretion Scale, and delayed or absent swallowing reflex. Decreased sensitivity according to the touch-technique correlated with the FEES-LSR-Test at 0.3 ml and 0.4 ml, but not at 0.2 ml and 0.5 ml trigger volumes.

CONCLUSIONS

Pharyngeal hypesthesia is a crucial factor in the development of PSD, leading to impaired secretion management and delayed or absent swallowing reflex. It can be investigated using both the touch-technique and the FEES-LSR-Test. In the latter procedure, trigger volumes of 0.4 ml are particularly suitable.

Endoscopic evaluation of pharyngeal and laryngeal sensation in patients with chronic obstructive pulmonary disease (COPD): A cross-sectional study

OBJECTIVE

To describe and compare the findings of endoscopic sensory assessment in COPD patients and healthy controls.

DESIGN

A prospective cross-sectional study.

SETTING

Otorhinolaryngology outpatient clinic at a university hospital.

PARTICIPANTS

27 adults with COPD and 11 age-matched healthy controls.

MAIN OUTCOME MEASURES

Group differences in light touch endoscopic tests of pharyngeal and laryngeal sensation, controlling for pooled salivary secretions in the pharynx and laryngo-pharyngeal reflux as measured by the Reflux Finding Score (RFS).

RESULTS

A significant difference in laryngeal sensation was found between the study groups (P = .047), with reduced laryngeal sensation in the COPD patients. Additionally, a significant relationship was found between impaired oropharyngeal sensation and the presence of pooled salivary secretions in the pharynx (P = .018), especially in the pyriform sinuses (P = .012). No differences in the frequency of abnormal RFSs were found between groups.

CONCLUSION

Individuals with COPD were significantly more likely to present with impaired laryngeal sensation. Additionally, impaired sensation in the oropharynx was associated with pooled salivary secretions in the pharynx.

FEES-based assessment of pharyngeal hypesthesia-Proposal and validation of a new test procedure

BACKGROUND

Intact pharyngeal sensation is essential for a physiological swallowing process, and conversely, pharyngeal hypesthesia can cause dysphagia. This study introduces and validates a diagnostic test to quantify pharyngeal hypesthesia.

METHODS

A total of 20 healthy volunteers were included in a prospective study. Flexible endoscopic evaluation of swallowing (FEES) and a sensory test were performed both before and after pharyngeal local anesthesia. To test pharyngeal sensation, a small tube was positioned transnasally in the upper third of the oropharynx with contact to the lateral pharyngeal wall. Increasing volumes of blue-dyed water were injected through the tube, and the latency of swallowing response (LSR) was determined by two independent raters from the endoscopic video recording. Three trials were performed for each administered volume starting with 0.1 mL and increased by 0.1 mL up to 0.5 mL.

KEY RESULTS

The average LSR without anesthesia was 2.24 ± 0.80 s at 0.1 mL, 1.79 ± 0.84 s at 0.2 mL, 1.29 ± 0.62 s at 0.3 mL, 1.17 ± 0.41 s at 0.4 mL, and 1.19 ± 0.52 s at 0.5 mL. With anesthesia applied, the average LSR was 2.65 ± 0.62 s at 0.1 mL, 2.64 ± 0.49 s at 0.2 mL, 2.44 ± 0.65 s at 0.3 mL, 2.10 ± 0.80 s at 0.4 mL, and 2.18 ± 0.85 s at 0.5 mL. LSR was significantly longer following anesthesia at 0.2 mL (t = -3.82; P = .001), 0.3 mL (t = -4.65; P < .000), 0.4 mL (t = -5.77; P < .000), and 0.5 mL (t = -3.49; P = .005).

CONCLUSION AND INFERENCES

Pharyngeal hypesthesia can be quantified with sensory testing using LSR. Suitable volumes to distinguish between normal and impaired pharyngeal sensation are 0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL. Experimentally induced pharyngeal anesthesia represents a valid model of sensory dysphagia.

Accuracy and reliability of the sensory test performed using the laryngopharyngeal endoscopic esthesiometer and rangefinder in patients with suspected obstructive sleep apnoea hypopnoea: protocol for a prospective double-blinded, randomised, exploratory study

INTRODUCTION

Patients with obstructive sleep apnoea hypopnoea syndrome (OSA) might have varying degrees of laryngopharyngeal mechanical hyposensitivity that might impair the brain's capacity to prevent airway collapse during sleep. However, this knowledge about sensory compromises in OSA comes from studies performed using methods with little evidence of their validity. Hence, the purpose of this study is to assess the reliability and accuracy of the measurement of laryngopharyngeal mechanosensitivity in patients with OSA using a recently developed laryngopharyngeal endoscopic esthesiometer and rangefinder (LPEER).

METHODS AND ANALYSIS

The study will be prospective and double blinded, with a randomised crossover assignment of raters performing the sensory tests. Subjects will be recruited from patients with suspected OSA referred for baseline polysomnography to a university hospital sleep laboratory. Intra-rater and inter-rater reliability will be evaluated using the Bland-Altman's limits of agreement plot, the intraclass correlation coefficient, and the Pearson or Spearman correlation coefficient, depending on the distribution of the variables. Diagnostic accuracy will be evaluated plotting ROC curves using standard baseline polysomnography as a reference. The sensory threshold values ​​for patients with mild, moderate and severe OSA will be determined and compared using ANOVA or the Kruskal-Wallis test, depending on the distribution of the variables. The LPEER could be a new tool for evaluating and monitoring laryngopharyngeal sensory impairment in patients with OSA. If it is shown to be valid, it could help to increase our understanding of the pathophysiological mechanisms of this condition and potentially help in finding new therapeutic interventions for OSA.

ETHICS AND DISSEMINATION

The protocol has been approved by the Institutional Review Board of Fundacion Neumologica Colombiana. The results will be disseminated through conference presentations and peer-reviewed publication.

TRIAL REGISTRATION

This trial was registered at Clinical Trials Accuracy of the sensory test using the lLaryngopharyngeal endoscopic esthesiometer in obstructive sleep apnea. Protocol ID: 201611-22405. ClinicalTrials.gov ID: NCT03109171.

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.

Improving the Utility of Laryngeal Adductor Reflex Testing

Objectives

Evaluation of the laryngeal adductor reflex (LAR) entails delivering air through an endoscope positioned 1 to 2 mm from the arytenoid mucosa to elicit bilateral vocal fold (VF) closure. This short working distance limits visualization to only the ipsilateral arytenoid and results in quantification of a single LAR metric: threshold pressure that evokes the LAR. Our goal was to evolve the LAR procedure to optimize its utility in clinical practice and translational research.

Study Design

Prospective translational experiment.

Setting

Academic institution.

Subjects

Young healthy human adults (n = 13) and 3 groups of mice: healthy, primary aging mice (n = 5), a transgenic mouse model of amyotrophic lateral sclerosis (ALS; n = 4), and young healthy controls (n = 10).

Methods

The VFs were visualized bilaterally during supramaximal air stimulation through an endoscope. Responses were analyzed to quantify 4 novel metrics: VF adduction phase duration, complete glottic closure duration, VF abduction phase duration, and total LAR duration.

Results

The 4 LAR metrics are remarkably similar between healthy young humans and mice. Compared to control mice, aging mice have shorter glottic closure durations, whereas ALS-affected mice have shorter VF abduction phase durations.

Conclusions

We have established a new LAR protocol that permits quantification of novel LAR metrics that are translatable between mice and humans. Using this protocol, we showed that VF adduction is impaired in primary aging mice, whereas VF abduction is impaired in ALS-affected mice. These preliminary findings highlight the enhanced diagnostic potential of LAR testing.

A comparison of 2 methods of endoscopic laryngeal sensory testing: a preliminary study

OBJECTIVE

This study examined the association between laryngeal sensory deficits and penetration or aspiration. Two methods of testing laryngeal sensation were carried out to determine which was more highly correlated with Penetration-Aspiration Scale (PAS) scores.

METHODS

Healthy participants and patients with dysphagia received an endoscopic swallowing evaluation including 2 sequential laryngeal sensory tests-air pulse followed by touch method. Normal/impaired responses were correlated with PAS scores.

RESULTS

Fourteen participants completed the endoscopic swallowing evaluation and both sensory tests. The air pulse method identified sensory impairment with greater frequency than the touch method (P<.0001). However, the impairment identified by the air pulse method was not associated with abnormal PAS scores (P=.46). The sensory deficits identified by the touch method were associated with abnormal PAS scores (P=.05).

CONCLUSION

Sensory impairment detected by the air pulse method does not appear to be associated with risk of penetration/aspiration. Significant laryngeal sensory loss revealed by the touch method is associated with compromised airway protection.

Neurophysiology and Clinical Implications of the Laryngeal Adductor Reflex

The laryngeal adductor reflex (LAR) is an involuntary protective response to stimuli in the larynx. The superior laryngeal nerve (SLN) acts as the afferent limb and the recurrent laryngeal nerve (RLN) as the efferent limb of this reflex, which is modulated by the central nervous system. Perhaps the most clinically significant application of the LAR is its use in laryngopharyngeal (LP) sensory discrimination testing. Importantly, aberrations in the LAR may predict dysphagia or portend clinical phenotypes of chronic cough, vocal cord dysfunction or pediatric apneas. LP sensation is a potential target for interventions addressing the aforementioned conditions though currently remains an area of active investigation.

Laryngeal sensory testing in the assessment of patients with laryngopharyngeal reflux

Laryngopharyngeal reflux is commonly encountered in the ENT out-patient setting. It leads to impaired sensory capacity of the laryngeal mucosa. The sensory integrity of the laryngopharynx can be evaluated through endoscopic administration of pulsed air, which stimulates the laryngeal adductor reflex. The pressure of air needed to elicit this reflex indicates the degree of sensory impairment. Such laryngeal sensory testing gives a quantifiable means of assessment in patients with laryngopharyngeal reflux, and can be used to measure the response to treatment. Laryngeal sensory testing is safe and well tolerated by patients.