Development, Reliability, and Validation of an Infant Mammalian Penetration–Aspiration Scale

Abstract

A penetration-aspiration scale exists for assessing airway protection in adult videofluoroscopy and fiberoptic endoscopic swallowing studies, however no such scale exists for animal models. The aim of this study was threefold to 1) develop a Penetration-Aspiration Scale (PAS) for infant mammals, 2) test the scale’s intra- and inter-rater reliability, and 3) to validate the use of the scale for distinguishing between abnormal and normal animals. After discussion and reviewing many videos, the result was a 7-Point Infant Mammal PAS. Reliability was tested by having 5 judges score 90 swallows recorded with videofluoroscopy across two time points. In these videos, the frame rate was either 30 or 60 frames per second and the animals were either normal, had a unilateral superior laryngeal nerve (SLN) lesion, or had hard palate local anesthesia. The scale was validated by having one judge score videos of both normal and SLN lesioned pigs and testing the difference using a t-test. Raters had a high intra-rater (average kappa of 0.82, intraclass correlation coefficient (ICC)= 0.92) and high inter-rater reliability (average kappa of 0.68, ICC= 0.66). There was a significant difference in reliability for videos captured at 30 and 60 frames per second for scores of 3 and 7 (p<0.001). The scale was also validated for distinguishing between normal and abnormal pigs (p<0.001). Given the increasing number of animal studies using videofluoroscopy to study dysphagia, this scale provides a valid and reliable measure of airway protection during swallowing in infant pigs that will give these animal models increased translational significance.

The Physiologic Impact of Unilateral Recurrent Laryngeal Nerve (RLN) Lesion on Infant Oropharyngeal and Esophageal Performance

“…All swallows in each feeding sequence were scored using the infant mammal penetration-aspiration scale (IMPAS) [29]. IMPAS scores range from 1 (safe swallow) to 7 (silent aspiration), and represent progressively more severe instances of dysphagia (Table 1).…”

“…IMPAS scores range from 1 (safe swallow) to 7 (silent aspiration), and represent progressively more severe instances of dysphagia (Table 1). All swallows were scored by a single investigator trained to use the scale following the guidelines in [29]. The investigator was blinded to treatment condition of pigs in the video sequences she scored.…”

Variation in the Timing and Frequency of Sucking and Swallowing over an Entire Feeding Session in the Infant Pig Sus scrofa

“…Infant pigs have been used in previous studies of normal feeding and swallowing neurophysiology, and thus a large body of comparable data exists for comparison with the results of this study [4, 12, 17, 21, 22]. The data used here were collected as control data in other studies of dysphagia [8, 9, 23, 24].…”

The Effect of Bilateral Superior Laryngeal Nerve Lesion on Swallowing: A Novel Method to Quantitate Aspirated Volume and Pharyngeal Threshold in Videofluoroscopy

“…In recent years, numerous 3D techniques have been widely developed and utilized like CT [21], ultrasound [22], photography [23] etc. With 3D techniques, measurement of volume instead of area is relatively easy.…”

“…Dysphagia, the inability to swallow safely, is a significant but overlooked problem that can result in aspiration pneumonia [1, 2]. The gold standard for quantifying the kinematics of swallowing is a video fluoroscopic swallowing study, using barium (Ba) as a contrast agent [3].…”