Quantifying Bolus Residue and Its Risks in Children: A Videofluoroscopic Study

Purpose Postswallow residue is a clinical sign of swallow impairment and has shown a strong association with aspiration. Videofluoroscopy (videofluoroscopic study of swallowing [VFSS]) is commonly used to visualize oropharyngeal swallowing and to identify pharyngeal residue. However, subjective binary observation (present or absent) fails to provide important information on volume or location and lacks objectivity and reproducibility. Reliable judgment of changes in residue over time and with treatment is therefore challenging. We aimed to (a) determine the reliability of quantifying pharyngeal residue in children using the bolus clearance ratio (BCR), (b) determine associations between BCR and other timing and displacement measures of oropharyngeal swallowing, and (c) explore the association between BCR and penetration–aspiration in children. Method In this single-center retrospective observational study, we obtained a set of quantitative and descriptive VFSS measures from 553 children (0–21 years old) using a standard protocol. VFSS data were recorded at 30 frames per second for quantitative analysis using specialized software. Results Good interrater (ICC = .86, 95% CI [.74, .961], p < .001) and excellent intrarater reliability was achieved for BCR (ICC = .97, 95% CI [.91, 1.000], p = 001). Significant correlations between BCR and pharyngeal constriction ratio and total pharyngeal transit time were reported ( p < .05). Using binomial logistic regression modeling, we found BCR was predictive of penetration–aspiration in children, χ 2 (13) = 58.093, p < .001, 64.9%. Children with BCR of ≥ 0.1 were 4 times more likely to aspirate. Conclusion BCR is a reliable, clinically useful measure to quantify postswallow residue in children, which can be used to identify and treat children with swallow impairments, as well as to measure outcomes of intervention.

Retrospective surprise: A computational component for active inference

In the free energy principle (FEP), proposed by Friston, it is supposed that agents seek to minimize the “surprise”–the negative log (marginal) likelihood of observations (i.e., sensory stimuli)–given the agents' current belief. This is achieved by minimizing the free energy, which provides an upper bound on the surprise. The FEP has been applied to action selection in a framework called “active inference,” where agents are supposed to select an action so that they minimize the “expected free energy” (EFE). While the FEP and active inference have attracted the attention of researchers in a wide range of fields such as psychology and psychiatry, as well as neuroscience, it is not clear which psychological construct EFE is related to. To facilitate the discussion and interpretation of psychological processes underlying active inference, we introduce a computational component termed the “retrospective (or residual) surprise,” which is the surprise of an observation after updating the belief given the observation itself. We show that the predicted retrospective surprise (PRS) provides a lower bound on EFE: EFE is always larger than PRS. We illustrate the properties of EFE and PRS using examples of inference for a binary hidden cause given a binary observation. Essentially, EFE and PRS show similar behavior; however, in certain situations, they provide different predictions regarding action selection. This study also provides insights into the mechanism of active inference based on EFE.

Evaluation of the technical condition of road transport means

The paper presents the methodology for determining the procedures of the condition and fault location test, using logical relations (0,1) between diagnostic parameters and technical conditions of the means of transport in the form of a binary observation matrix, determination of the status control and fault location test and use of diagnostic information received during use of means of transport. Implementation of the proposals included in the study should increase the efficiency of diagnosing means of transport, and thus contribute to activities that rationalize their exploitation.