Videofluoroscopic analysis of different volumes of liquid bolus swallowing in healthy individuals: comparison between height and sex

Inter-rater reliability and clinical relevance of subjective and objective interpretation of videofluoroscopy findings

Background

Dysphagia is commonly evaluated using videofluoroscopy (VFS). As its ratings are usually subjective normal-abnormal ratings, objective measurements have been developed. We compared the inter-rater reliability of the usual VFS ratings to the objective measurement VFS ratings and evaluated their clinical relevance.

Methods

Two blinded raters analyzed the subjective normal-abnormal ratings of 77 patients' VFS. Two other blinded raters analyzed the objective measurements of pharyngeal aerated area with bolus held in the oral cavity (PAhold), the pharyngeal area of residual bolus during swallowing (PAmax), the pharyngeal constriction ratio (PCR), the maximum pharyngoesophageal segment opening (PESmax), pharyngoesophageal segment opening duration (POD), airway closure duration (ACD), and total pharyngeal transit time (TPT). We evaluated the inter-rater agreement in the subjective ratings and the objective measurements. Clinical utility analysis compared the measurements with the VFS findings of pharyngeal phase abnormality, penetration/aspiration, and cricopharyngeal relaxation.

Results

In the pharyngeal findings, the subjective analysis inter-rater agreement was mainly moderate to strong. The strongest agreements were on the pharyngeal residues and penetration/aspiration findings. The objective measurements had fair to good inter-rater agreement. Clinical utility analysis found statistically significant connections between TPT and pharyngeal phase abnormality, normal PCR and lack of penetration/aspiration, and normal PESmax and normal cricopharyngeal relaxation.

Conclusions

The subjective analysis had moderate to strong inter-rater agreement in the pharyngeal VFS findings, especially concerning pharyngeal residues and penetration/aspiration detection, reflecting the efficacy and safety of swallowing. The objective measurements had fair to good inter-observer reproducibility and could thus improve the reliability of VFS diagnostics.

Level of evidence

4.

Location of the upper oesophageal sphincter during swallowing: Analysis using swallowing CT

BACKGROUND

Upper oesophageal sphincter (UES) serves as an important anatomical and functional landmark during swallowing. However, the precise UES location before and during swallowing has not been well established.

OBJECTIVE

This study aimed to determine upper oesophageal sphincter (UES) location and displacement during swallowing accounting for sex, age, and height in healthy adults using 320-row area detector computed tomography (320-ADCT).

METHODS

Ninety-four healthy adults (43 males; 22-90 years) underwent 320-ADCT scanning while swallowing one trial of 10 mL honey thick barium. UES location at bolus hold and at maximum displacement and vertical displacement during swallowing were identified using the coordinates and the section classification of vertebrae (VERT scale). The differences and correlations of UES location and distance in terms of sex, age, and height were analysed using Mann-Whitney U test and Spearman's correlation coefficient.

RESULTS

UES locations at bolus hold and at maximum displacement were significantly lower and UES vertical displacement was significantly larger in males than in females (p < .001). UES location at bolus hold became lower with increasing age (r = -.312, p = .002), but the negative correlation was low at maximum displacement (r = -.230, p = .026), resulting in larger vertical distance with ageing. UES locations showed high negative correlation at bolus hold with height (r = -.715, p < .001), and showed moderate negative correlation at maximum displacement with height (r = -.555, p < .001), although this effect was unclear when analysed by sex.

CONCLUSION

Males showed lower UES location and larger displacement than females. The impact of age was evident with lower location before swallowing and larger displacement during swallowing. Differences observed by sex were not completely explained by using the VERT scale to adjust for height.

Thin Liquid Bolus Volume Alters Pharyngeal Swallowing: Kinematic Analysis Using 3D Dynamic CT

The previous studies reported that different volumes of thick liquid had an impact on spatiotemporal characteristics and pharyngeal response of swallowing. However, the bolus flow and swallowing motion pattern were different between thick and thin liquids. The effects of thin bolus volume on pharyngeal swallowing, especially true vocal cord (TVC) closure is still unclear. This study assessed the temporal characteristics when swallowing different volumes of thin liquid to determine the mechanical adaptation using 320-row area detector computed tomography (320-ADCT) and investigated a change of swallowing physiology including laryngeal closure, particularly TVC closure. Fourteen healthy women (28-45 years) underwent 320-ADCT while swallowing of 3, 10, and 20 ml of thin liquid barium in 45° semi-reclining position. Kinematic analysis was performed for each swallow including temporal characteristic, structural movements while swallowing, and maximal cross-sectional area of the upper esophageal sphincter (UES) opening. Bolus head reached to pharynx and esophagus earlier in larger volume significantly, indicating faster bolus transport as volume increased. There were significant effects on swallowing mechanism revealing earlier TVC closure and UES opening with increasing volume. Maximum cross-sectional area of the UES opening was increased to accommodate a larger bolus. Differences in mechanical adaptation through bolus transit and motion of swallowing structures were detected across increasing volumes. These volume-dependent adaptations potentially reduce the risk of aspiration. Understanding the swallowing physiological changes as volume increased is helpful for diagnosis and treatment of dysphagia patients as well as outcomes of swallowing rehabilitation in clinical practice.

Influence of Body Height on Oral and Pharyngeal Transit Time of a Liquid Bolus in Healthy Volunteers

BACKGROUND

Swallowing duration may be influenced by several factors. The effect of body height on oral-pharyngeal bolus transit has not been clearly elucidated. The hypothesis of this investigation was that height has influence on oral-pharyngeal transit time of a liquid bolus.

METHODS

Videofluoroscopic assessment of swallowing was performed on 40 healthy volunteers: 20 "tall" (171 cm to 207 cm) and 20 "short" (152 cm to 170 cm) subjects, 10 men and 10 women in each group. Each subject performed three swallows of 10 mL of liquid barium bolus. The following parameters were measured: oral transit time (OTT): time from the beginning of tongue tip movement at incisors to arrival of the bolus tail at the fauces; pharyngeal transit time (PTT): time between the arrival of the bolus tail at fauces and complete passage of the bolus tail through the upper esophageal sphincter (UES); pharyngeal clearance (PC): time between the arrival of the bolus head at fauces to complete passage of the bolus tail through the UES; UES opening (UESO): time between the arrival of the bolus head at the UES to complete passage of the bolus tail through the UES; duration of hyoid movement (HM): time interval between the onset and the end of hyoid movement; oral-pharyngeal transit time (OPTT): time from the beginning of tongue tip movement at incisors until complete passage of the bolus tail through the UES. The statistical analysis was done by a linear model with mixed effects. Correlation between height and swallowing events duration was assessed by Spearman's correlation coefficient (r).

RESULTS

In women OTT, PC, HM and OPTT were longer in tall than in short subjects, what was not seen in men. In women there was a positive correlation between OTT, PTT and OPTT and height. Men (mean height: 177 cm) had longer PTT and PC than women (mean height: 166 cm).

CONCLUSIONS

In women, oral and pharyngeal transit time of a 10 mL liquid bolus were influenced by height and was longer in taller subjects.