The Effect of Bolus Consistency and Sex on Electrophysiological Measures of Hyolaryngeal Muscle Activity During Swallowing

Pilot Study: Magnetic Motion Analysis for Swallowing Detection Using MEMS Cantilever Actuators

The swallowing process involves complex muscle coordination mechanisms. When alterations in such mechanisms are produced by neurological conditions or diseases, a swallowing disorder known as dysphagia occurs. The instrumental evaluation of dysphagia is currently performed by invasive and experience-dependent techniques. Otherwise, non-invasive magnetic methods have proven to be suitable for various biomedical applications and might also be applicable for an objective swallowing assessment. In this pilot study, we performed a novel approach for deglutition evaluation based on active magnetic motion sensing with permanent magnet cantilever actuators. During the intake of liquids with different consistency, we recorded magnetic signals of relative movements between a stationary sensor and a body-worn actuator on the cricoid cartilage. Our results indicate the detection capability of swallowing-related movements in terms of a characteristic pattern. Consequently, the proposed technique offers the potential for dysphagia screening and biofeedback-based therapies.

A comparison of swallow-related submandibular contraction amplitude and duration in people with Parkinson's disease and healthy controls

PURPOSE

To compare the contraction amplitude and contraction duration of submandibular muscles during the pharyngeal stage of swallowing in people with Parkinson's disease (PD) compared to normal controls.

METHOD

A prospective cross-sectional study design was utilised to recruit 24 participants from the regional area. A total of 14 people with PD and 10 healthy controls (HC) were recruited. Participants swallowed three volumes of thin liquid (5mL, 10mL, 15mL) while the activity of the submandibular muscles was recorded using surface electromyography. Measurements of contraction amplitude ratio (normalised to a maximum voluntary contraction) and contraction duration were computed from recorded electromyographic signals. Receiver Operating Characteristics (ROC) were computed for variables associated with significant main effects.

RESULT

Analyses revealed a significant effect of group on contraction amplitude ratio but not contraction duration. There were no significant effects of bolus volume on the dependent variables. ROC analysis indicated that contraction amplitude ratio accurately predicted group assignment in 77% cases.

CONCLUSION

Findings revealed that a majority of people with PD in this study utilised a greater percentage of their maximum contraction force in submandibular muscles when swallowing compared to normal controls. Further research is needed to determine if this inefficiency is consistent across larger samples and whether it is due to elevated baseline muscle activity, a compensatory behaviour to accomplish a more effective swallow, or both.

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.

A review of diet standardization and bolus rheology in the management of dysphagia

PURPOSE OF REVIEW

Texture modification is a widespread practice as a strategy for the management of dysphagia and can be very effective in individual cases. However, it is often performed in a qualitative, subjective manner and practices vary internationally according to multiple sets of national guidelines. This article aims to identify best practice by reviewing the theory and practice of texture modification, focussing on recent advances.

RECENT FINDINGS

Instrumental assessment of texture modification in vivo is challenging, and studies including rheology and perception have indicated that fluid viscosity is only one of many factors affecting texture modification in practice. Systematic reviews have identified a historical lack of high-quality clinical evidence, but recent controlled studies are beginning to identify positive and negative aspects of thickened fluids. Research and practice to date have been limited by the lack of control and standardization of foods and drinks. However in 2015 a not-for-profit organization, the International Dysphagia Diet Standardisation Initiative, has published a framework for texture modification from thin liquids to solid foods based on all the existing documentation and guidance, and the - limited - available clinical evidence.

SUMMARY

Rheology exists in the lab; however, normal practice is often subjective or lacking control and standardization. In the near future, cohesion of practice and the availability of practical standardization tools may increase awareness and use of rheology.

Evaluation of normal swallowing functions by using dynamic high-density surface electromyography maps

BACKGROUND

Swallowing is a continuous process with substantive interdependencies among different muscles, and it plays a significant role in our daily life. The aim of this study was to propose a novel technique based on high-density surface electromyography (HD sEMG) for the evaluation of normal swallowing functions.

METHODS

A total of 96 electrodes were placed on the front neck to acquire myoelectric signals from 12 healthy subjects while they were performing different swallowing tasks. HD sEMG energy maps were constructed based on the root mean square values to visualize muscular activities during swallowing. The effects of different volumes, viscosities, and head postures on the normal swallowing process were systemically investigated by using the energy maps.

RESULTS

The results showed that the HD sEMG energy maps could provide detailed spatial and temporal properties of the muscle electrical activity, and visualize the muscle contractions that closely related to the swallowing function. The energy maps also showed that the swallowing time and effort was also explicitly affected by the volume and viscosity of the bolus. The concentration of the muscular activities shifted to the opposite side when the subjects turned their head to either side.

CONCLUSIONS

The proposed method could provide an alternative method to physiologically evaluate the dynamic characteristics of normal swallowing and had the advantage of providing a full picture of how different muscle activities cooperate in time and location. The findings from this study suggested that the HD sEMG technique might be a useful tool for fast screening and objective assessment of swallowing disorders or dysphagia.

Nutritional Aspects of Dysphagia Management

This chapter describes the nutritional aspects of dysphagia management by starting with the definition of these two conditions (dysphagia and malnutrition) that share three main clinical characteristics: (a) their prevalence is very high, (b) they can lead to severe complications, and (c) they are frequently underrecognized and neglected conditions. From an anatomical standpoint, dysphagia can result from oropharyngeal and/or esophageal causes; from a pathophysiological perspective, dysphagia can be caused by organic or structural diseases (either benign or malignant) or diseases causing impaired physiology (mainly motility and/or perception disorders). This chapter gathers up-to-date information on the screening and diagnosis of oropharyngeal dysphagia, the consequences of dysphagia (aspiration pneumonia, malnutrition, and dehydration), and on the nutritional management of dysphagic patients. Concerning this last topic, this chapter reviews the rheological aspects of swallowing and dysphagia (including shear and elongational flows) and its influence on the characteristics of the enteral nutrition for dysphagia management (solid/semisolid foods and thickened liquids; ready-to-use oral nutritional supplements and thickening powders), with special focus on the real characteristics of the bolus after mixing with human saliva.