Reconsideration of three screening tests for dysphagia in patients with cerebrovascular disease performed by non-expert examiners

Difference in the Electromyographic Behavior of the Masticatory and Swallowing Muscles During Cued Versus Spontaneous Swallowing

The risk of dysphagia and/or aspiration is determined using screening tests, such as the repeated saliva swallowing test and modified water swallowing test, which evaluate cued swallowing. However, humans masticate and swallow foods with various consistencies, forms, and amounts, without conscious awareness. Therefore, this study aimed to examine the difference in the behavior of masticatory and swallowing muscles during spontaneous versus cued swallowing through a series of mastication and swallowing processes by evaluating surface electromyogram (sEMG) signals. The effect of the consistency and amount of food on the behavior of these muscles was also investigated. The sEMG recordings of the masseter muscles and anterior belly of the digastric muscle for 12 subjects, and genioglossus muscle for 5 subjects were obtained. The genioglossus activity was recorded using custom-made ball electrodes. The test foods were cookies and tofu, in amounts of 2 g and 4 g. The normalized muscle activity (integrated EMG), duration of the muscle activity, initial activation timepoint of each muscle, and total duration of swallowing were compared among four conditions. The activity of each muscle was significantly higher during the swallowing of cookies than tofu, for 4 g vs 2 g, and for cued versus spontaneous swallowing. The duration of each muscle activity, initial activation timepoint, and total duration of swallowing were significantly longer for cookies versus tofu, for 4 g vs 2 g, and for spontaneous versus cued swallowing. These results suggest that the behavior of the masticatory and swallowing muscles is affected by cued swallowing and by the consistency and amount of food.

Temporal characteristics of aspiration pneumonia in elderly inpatients: From resumption of oral intake to onset

Background

Elderly inpatients who develop fevers after resumption of oral intake are often considered to have aspiration pneumonia (AP) and be tentatively fasted. Fasting has been associated with prolonged hospital stays and decreased swallowing ability. The purpose of this study was to compare AP and other infections after resumption of oral intake in elderly inpatients and to identify the clinical characteristics.

Patients and methods

The records of patients who were admitted to a public tertiary hospital and referred for evaluation of swallowing disability were retrospectively reviewed to identify those who had developed AP, non-AP, or urinary tract infection (UTI) after resumption of oral intake. Eligible patients were enrolled consecutively in the study. The patient characteristics, physical findings, laboratory data, oral intake status at the time of onset of symptoms, and rate of discontinuation of oral intake after onset of infection were compared between the three types of infection.

Results

A total of 193 patients developed an infectious illness after resuming oral intake. Among them, 114 patients had a diagnosis of AP (n = 45), non-AP (n = 24), or UTI (n = 45). There were no significant differences in patient characteristics, physical findings or laboratory data between the group with AP and the other two groups. AP developed at a median of 6 (range 1–16) days after resumption of oral intake. The rate of discontinuation of oral intake was 91.1% in the AP group, 58.3% in the non-AP group, and 26.7% in the UTI group, respectively.

Conclusion

Infectious diseases other than AP should be considered in the differential diagnosis when nosocomial fever develops in elderly inpatients more than 17 days after resuming oral intake. Furthermore, nosocomial fever after resuming oral intake has many causes other than AP, and discontinuation of oral intake should be carefully considered.

Real-time assessment of swallowing sound using an electronic stethoscope and an artificial intelligence system

Objectives

Daily assessments of swallowing function and interventions such as rehabilitation and dietary adjustments are necessary to improve dysphagia. Cervical auscultation is convenient for health care providers for assessing swallowing ability. Although this method allows for swallowing sound evaluations, sensory evaluations with this method are difficult. Thus, we aimed to assess swallowing sound by the combined use of an electronic stethoscope and an artificial intelligence (AI) system that incorporates sound recognition.

Material and Methods

Herein, 20 fifth‐year dentistry student volunteers were included; each participant was drank 10 ml and then 20 ml of water in different positions (sitting and supine). We developed an algorithm for indexing bolus inflow sounds using AI, which compared the swallowing sounds and created a new index.

Results

The new index value used for swallowing sound was significantly higher in men than in women and in the sitting position than in the supine position. A software for acoustic analysis confirmed that the swallowing index was significantly higher in men than in women as well as in the sitting position than in the supine position. These results were similar to those obtained using the new index. However, the new index substantially differed between sexes in terms of posture compared with effective sound pressure.

Conclusions

We developed a new algorithm for indexing swallowing sounds using a stethoscope and an AI system, which could identify swallowing sounds. For future research and development, evaluations of patients with dysphagia are necessary to determine the efficacy of the new index for bedside screening of swallowing conditions.

Decision making and the bedside assessment: The Speech Language Therapists' thinking when making a diagnosis at the bed

BACKGROUND

The bedside assessment is often seen as a screener because of its high variability in sensitivity and specificity, whilst the instrumental measures are viewed as gold standards because of the ability of speech-language therapist (SLT) to visualise the swallow more objectively.

OBJECTIVES

This research article explores how the value needs to be placed on the decision-making abilities of the SLT rather than on the assessment measure itself.

METHOD

A mixed methodology concurrent triangulation design was employed to collect data in two phases: the first phase included observing seven SLTs conducting assessments using a standardised bedside measure together with pulse oximetry and cervical auscultation. The second phase was a focus group discussion based on the findings from the first phase. Data were analysed thematically using a bottom-up approach.

RESULTS

The following factors were found to influence the decision-making process at the bedside: bedside assessment data sets, patient, multidisciplinary team, context and then SLT. The availability of more data from the assessment from different data sets improved the confidence of the SLT at the bedside when needing to make clinical decisions. Clinical instincts are developed through experience and observation of those more experienced. These skills need to be developed from junior years.

CONCLUSION

This research study showed that a bedside assessment can provide valuable information that will allow for diagnostic decisions to be made at the bedside. This study also highlighted the importance of critical thinking using clinical instincts, and that these are the factors that need to be valued and emphasised rather than the assessment measures themselves.

Relationship between lip motion detected with a compact 3D camera and swallowing dynamics during bolus flow swallowing in Japanese elderly men

Clinical application of a swallowing function evaluation system that is minimally invasive and enables an objective evaluation is necessary. We constructed a system that can synchronise and analyse lip motion with a three-dimensional (3D) camera and swallowing dynamics with videofluoroscopy (VF) and clarified the relationship between lip movement and swallowing dynamics. A compact 3D camera was adapted to Microsoft XBox One Kinect Sensor^® . We examined Kinect's accuracy and repeatability and analysed the highest measurement accuracy and repeatability of the distance between anguli oris muscles. The constructed system simultaneously measured, synchronised and analysed lip motion by Kinect and swallowing dynamics by VF. Fourteen elderly men without dysphagia were included. Barium turbid solution (5, 10, 15 and 20 mL) was used for swallowing. Measurement parameters were the 3D distance between angulus oris displacement (TDDD), swallowing quantity (SQ), oral transit time (OTT), stage transit duration (STD), pharyngeal transit time (PTT) and total swallowing duration (TSD). Statistical analyses were performed. The measurement accuracy and reproducibility were optimum within a 10° horizontal imaging angle at a 120-cm measurement distance. SQ, TDDD, OTT, STD, PTT and TSD showed significant differences, and correlation was found between TDDD and OTT. SQ affected TDDD, OTT, STD, PTT and TSD; OTT could be predicted from TDDD. Improvement in the system and analysis method was considered to enable prediction of swallowing dynamics from body surface movement of the head and neck, including realisation of measurement conditions with higher precision and reproducibility, and from lip motion.