Developing a Protocol for Quantitative Analysis of Liquid Swallowing in Children

Inter-rater and Intra-rater Reliability of the Videofluoroscopic Dysphagia Scale with the Standardized Protocol

This study aimed to develop a standardized protocol for the assessment of videofluoroscopic dysphagia scale (VDS) and to demonstrate the inter-rater and intra-rater reliability of the VDS by applying the new standard protocol. A standardized protocol for the VDS was developed by dysphagia experts, including the original developer. To identify the reliability of the VDS using the protocol, 60 patients who underwent videofluoroscopic swallowing study (VFSS) for various etiologies were recruited retrospectively from three tertiary medical centers. Ten randomly selected cases were duplicated to evaluate the intra-rater reliability. Six physicians evaluated the VFSS data sets. Intraclass correlation coefficients were calculated for inter-rater and intra-rater reliability of the VDS score, and Gwet's kappa values for each VDS item were calculated. The inter-rater and intra-rater reliability of the total VDS score was 0.966 and 0.896, respectively. Notably, the evaluators' experience did not appear to have a significant impact on the reliability (physiatrists: 0.933/0.869, residents: 0.922/0.922). The reliability was consistent across different centers and dysphagia etiologies. The inter-rater and intra-rater reliability of the oral and pharyngeal sub-scores were 0.953/0.861 and 0.958/0.907, respectively. The inter-rater agreement of individual items ranged from 0.456 to 0.929, and nine items demonstrated good to very good level of agreement. Assessment of dysphagia using the VDS with the standard protocol showed excellent inter-rater and intra-rater reliabilities regardless of the evaluator's experience, VFSS equipment, and dysphagia etiologies. The VDS can be a useful assessment scale in the quantitative analysis of dysphagia based on VFSS findings.

Influence of frame rate in detecting oropharyngeal aspiration in paediatric videofluoroscopic swallow studies - An observational study

OBJECTIVES

The videofluoroscopic swallow study (VFSS), currently the gold standard for assessing aspiration in children, incurs radiation. Adhering to the ALARA principle is crucial in minimising radiation dose whilst obtaining accurate diagnostic information in children. International adult VFSS guidelines recommend a capture rate of 30 frames per second (fps). Higher capture rates increase radiation yet there is limited evidence on best practice VFSS capture rates in children, particularly on thin fluid consistency-the fastest viscosity with the highest potential for missed aspiration on slower capture rates. We aimed to determine if image acquisition at 30fps versus 15fps alters the accuracy of detecting aspiration when assessing thin fluids during paediatric VFSS.

MATERIALS & METHODS

Seventeen speech language pathologists (SLPs) blindly rated a total of 2,356 swallow loops for the presence/absence of aspiration from VFSS recordings of 13 infants/children drinking thin fluids. 76 swallow loops were randomly presented at 15 versus 30fps, on two occasions. Area under receiver operating curve (aROCs) was used to compare the accuracy of aspiration ratings at 15 versus 30fps compared to a comparison set. The intraclass correlation coefficient (ICC) was used to examine rater reliability.

RESULTS

Accuracy for detecting aspiration was near-identical at 15fps (aROC:0.97; 95%CI:0.96-0.97) and 30fps (0.96; 95%CI 0.96-0.97). Good inter-rater (ICC:0.82; 95%CI:0.72-0.89) and intra-rater reliability among the raters (ICC:0.89; 95%CI:0.82-0.93) was found.

CONCLUSION

Using 15fps in paediatric VFSS when assessing thin fluid consistency aspiration provides a similar detection rate to using 30fps. As 15fps would have a lower radiation dose than 30fps, we recommend using 15fps when undertaking VFSS in children.

CLINICAL RELEVANCE STATEMENT

Adhering to the ALARA principles, a capture rate of 15fps should be used in paediatric VFSS for assessment on thin fluids.

Exploring Reliable and Identifiable Quantitative Anatomical, Timing, and Displacement Measures in the VFS of Speech

AIM

Videofluroscopy studies of speech are a recognized assessment of velopharyngeal insufficiency (VPI). Yet, this method is subjective and has low inter-rater reliability. Quantitative measures of timing, distance, and area in videofluoroscopic studies of swallowing have been shown to be valid and reliable, but quantitative measures are not routinely used in videofluroscopy studies for VPI. This study explored the use of quantitative measures in patients with VPI in terms of feasibility and reliability.

METHODS

Forty patients of mixed etiology diagnosed with VPI through perceptual speech assessment underwent videofluroscopy. Anatomical landmarks and timing, distance, and area measurements were taken of the velopharyngeal port at rest and during speech tasks using specialized Swallowtail software. 50% of measures were double-blind rated to test inter-rater reliability. Raters reported on the time they took to complete each assessment and the challenges they had. Associations between measures were explored.

RESULTS

Ten timing, line, and area measures were developed based on 3 landmarks. Measures had moderate-substantial inter-rater reliability (intraclass coefficient: 0.69-0.91) except for time to lift (secs), which only achieved fair agreement (intraclass coefficient: 0.56). Measures demonstrated internal consistency ( R >0.60). Raters took, on average, 15 mins per patient and reported some challenges with image resolution, especially in timing measures where structures were blurred by movement.

CONCLUSION

Quantitative measures are reliable and have the potential to add novel information regarding VPI to support multidisciplinary decision-making. Further research with larger patient cohorts is needed to clarify how quantitative measures can support tailored decisions about surgical and therapeutic interventions in order to maximize outcomes for individuals.

Bolus Clearance Ratio Elevated in Patients With Neurogenic Dysphagia Compared With Healthy Adults: A Measure of Pharyngeal Efficiency

PURPOSE

Postswallow pharyngeal residue is a risk factor for aspiration, implies swallowing inefficiency, and increases the work of eating. The Bolus Clearance Ratio (BCR) is a derived metric that relates quantities of bolus material observed in the pharynx at two different points: before and after a swallow. The ratio provides a percentage estimate of bolus clearance. In healthy adults, mean BCR is < .05; that is, less than 5% of an ingested bolus is retained in the pharynx. The aim of this study was to compare BCR measures from patients referred for videofluoroscopic swallow studies with concerns related to stroke (n = 100) or other neurological conditions (n = 131, including Parkinson's disease and dementia) with BCRs for 139 healthy adults across the age range.

METHOD

BCR for a 20 ml of thin liquid barium bolus was measured. Additional metrics included age, penetration-aspiration scale (PAS) score, and quantitative measures of timing and displacement. Correlations were explored between BCR and pharyngeal constriction ratio (PCR), pharyngoesophageal segment opening (PESmax), maximum hyoid displacement (HMax), and total pharyngeal transit time (TPT).

RESULTS

BCR values for patients with stroke (Mdn = 9%, interquartile range [IQR]: 19%, range: 0%-73%) and other neurological conditions (Mdn = 9%, IQR: 16%, range: 0%-96%) were significantly higher than in healthy norms (Mdn = 2%, IQR: 4%, range: 0%-16%, p < .001). BCR was significantly correlated with age (R _s = .23, p < .01), TPT (R _s = .20, p < .01), PCR (R _s = .55, p < .01), PESmax (R _s = -.17, p < .01), HMax (R _s = -.16, p < .01), and PAS (R _s = .38, p < .01).

CONCLUSIONS

BCR was elevated in patients with neurogenic dysphagia in comparison with healthy norms and was significantly associated with increased aspiration severity (i.e., PAS). BCR was also correlated with pharyngeal timing and displacement parameters, with the strongest correlation with pharyngeal constriction-a measure of pharyngeal strength. The BCR offers clinicians a simple, quantitative measure of bolus residue and, therefore, pharyngeal efficiency and may be used to assess change in patients over time and with treatment.