Videofluoroscopic evaluation of dysphagia in motor neurone disease with modified barium swallow

In silicomuscle volume conduction study validatesin vivomeasurement of tongue volume conduction properties using a user tongue array depressor

Objective.Electrophysiological assessment of the tongue volume conduction properties (VCPs) using our novel multi-electrode user tongue array (UTA) depressor has the promise to serve as a biomarker in patients with bulbar dysfunction. However, whetherin vivodata collected using the UTA depressor accurately reflect the tongue VCPs remains unknown.Approach.To address this question, we performedin silicosimulations of the depressor with an accurate anatomical tongue finite element model (FEM) using healthy human tongue VCP values, namely the conductivity and the relative permittivity, in the sagittal plane (i.e. longitudinal direction) and axial and coronal planes (i.e. transverse directions). We then established the relationship between tongue VCP values simulated from our model to measured human data.Main results.Experimental versus simulated tongue VCP values including their spatial variation were in good agreement with differences well within the variability of the experimental results. Tongue FEM simulations corroborate the feasibility of our UTA depressor in assessing tongue VCPs.Significance.The UTA depressor is a new non-invasive and safe tool to measure tongue VCPs. These electrical properties reflect the tongue's ionic composition and cellular membrane integrity and could serve as a novel electrophysiological biomarker in neurological disorders affecting the tongue.

A Bioimpedance-Based Device to Assess the Volume Conduction Properties of the Tongue in Neurological Disorders Affecting Bulbar function

Goal: Current instruments for bulbar assessment exhibit technical limitations that hinder the execution of clinical studies. The volume conduction properties (VCP) of the tongue reflect ionic content and myofiber integrity and they can serve as a new biomarker for evaluating neurological disorders with bulbar dysfunction. Methods: We designed a standalone bioimpedance measurement system that enables accurate, multi-frequency measurement of tongue anisotropic VCP including conductivity and relative permittivity. The system includes a tongue depressor with 16 non-invasive surface sensors for electrical contact with the tongue at directions 0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$^{\circ }$\end{document}, 45\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$^{\circ }$\end{document}, 90\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$^{\circ }$\end{document} and 150\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$^{\circ }$\end{document}. The depressor is interfaced with the tongue electronic system with Bluetooth connectivity, and a smartphone application. De-identified patient data is sent by email. Results: We first determined the accuracy of the hardware performing phantom measurements mimicking a broad range of tongue values and determined the error to be \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$< $\end{document}1%. We then validated our new technology measuring a cohort of 7 healthy human subjects under Institutional Review Board approval. Conclusions: None of the subjects who participated suffered discomfort or gag reflexes. The novel technique presented for intra-oral assessment of tongue VCP provides standard, objective and quantitative data potentially sensitive to alterations in tongue internal structure and composition.

In vivo muscle conduction study of the tongue using a multi-electrode tongue depressor

OBJECTIVE

To test a novel technology for assessment of the volume conduction properties (VCPs) of the tongue. These properties are electrophysiological data that might reflect alterations in patients with tongue involvement.

METHODS

Seven healthy individuals were self-measured. The depressor was placed on the surface of the anterior tongue. Directional differences of VCPs were determined with standard descriptive statistics.

RESULTS

Conductivity in longitudinal direction was larger than in transverse direction at 16 (p < 0.05), 32 (p < 0.05), 64 (p < 0.01), and 128 kHz (p < 0.01). No differences were found in relative permittivity. The intraclass correlation was 0.778 and 0.771, respectively.

CONCLUSIONS

Our technology provides, for the first time, VCPs of the healthy human tongue.

SIGNIFICANCE

Tongue VCPs are standard electrophysiological, quantitative and objective data reflecting ionic content and membrane integrity which could find value for diagnostic purposes and treatment monitoring.

Optimizing the Translational Value of Mouse Models of ALS for Dysphagia Therapeutic Discovery

The goal of this study was to compare dysphagia phenotypes in low and high copy number (LCN and HCN) transgenic superoxide dismutase 1 (SOD1) mouse models of ALS to accelerate the discovery of novel and effective treatments for dysphagia and early amyotrophic lateral sclerosis (ALS) diagnosis. Clinicopathological features of dysphagia were characterized in individual transgenic mice and age-matched controls utilizing videofluoroscopy in conjunction with postmortem assays of the tongue and hypoglossal nucleus. Quantitative PCR accurately differentiated HCN-SOD1 and LCN-SOD1 mice and nontransgenic controls. All HCN-SOD1 mice developed stereotypical paralysis in both hindlimbs. In contrast, LCN-SOD1 mice displayed wide variability in fore- and hindlimb involvement. Lick rate, swallow rate, inter-swallow interval, and pharyngeal transit time were significantly altered in both HCN-SOD1 and LCN-SOD1 mice compared to controls. Tongue weight, tongue dorsum surface area, total tongue length, and caudal tongue length were significantly reduced only in the LCN-SOD1 mice compared to age-matched controls. LCN-SOD1 mice with lower body weights had smaller/lighter weight tongues, and those with forelimb paralysis and slower lick rates died at a younger age. LCN-SOD1 mice had a 32% loss of hypoglossal neurons, which differed significantly when compared to age-matched control mice. These novel findings for LCN-SOD1 mice are congruent with reported dysphagia and associated tongue atrophy and hypoglossal nucleus pathology in human ALS patients, thus highlighting the translational potential of this mouse model in ALS research.

Clinical Measures of Bulbar Dysfunction in ALS

Bulbar impairment represents a hallmark feature of Amyotrophic Lateral Sclerosis (ALS) that significantly impacts survival and quality of life. Speech and swallowing dysfunction are key contributors to the clinical heterogeneity of ALS and require well-timed and carefully coordinated interventions. The accurate clinical, radiological and electrophysiological assessment of bulbar dysfunction in ALS is one of the most multidisciplinary aspects of ALS care, requiring expert input from speech-language pathologists (SLPs), neurologists, otolaryngologists, augmentative alternative communication (AAC) specialists, dieticians, and electrophysiologists—each with their own evaluation strategies and assessment tools. The need to systematically evaluate the comparative advantages and drawbacks of various bulbar assessment instruments and to develop integrated assessment protocols is increasingly recognized. In this review, we provide a comprehensive appraisal of the most commonly utilized clinical tools for assessing and monitoring bulbar dysfunction in ALS based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) evaluation framework. Despite a plethora of assessment tools, considerable geographical differences exist in bulbar assessment practices and individual instruments exhibit considerable limitations. The gaps identified in the literature offer unique opportunities for the optimization of existing and development of new tools both for clinical and research applications. The multicenter validation and standardization of these instruments will be essential for guideline development and best practice recommendations.

Trends in Research Literature Describing Dysphagia in Motor Neuron Diseases (MND): A Scoping Review

Dysphagia in motor neuron diseases (MNDs) is highly complex, affecting all stages of swallowing and leading to impaired swallowing safety and efficiency. In order to explore the degree to which research is capturing the symptom of dysphagia in MND, we conducted a scoping review of the existing literature. The primary aims of this review were to identify common themes within the literature on dysphagia in MND, explore patterns and trends in research focus, and identify if any imbalances exist between the research themes related to dysphagia description and management. A comprehensive search strategy yielded 1690 unique articles for review. Following relevance screening, a total of 157 articles were included in the synthesis. Relevant data and keywords were extracted from each article and grouped into themes. Frequency estimates were calculated for each theme to identify trends across research literature. Swallowing impairment in MNDs is described in a variety of ways across current research. The most commonly reported theme was Aspiration/Penetration, mentioned in 73.2% of all included articles; a significant imbalance was identified between reports of swallowing safety and efficiency (p = 0.008). The most frequently reported theme related to dysphagia management was Enteral Nutrition, and very few studies have reported on the efficacy of Rehabilitation/Compensatory recommendations. It is suggested that researchers and clinicians remain mindful of imbalances and gaps in research, and aim to characterize dysphagia in MNDs in a comprehensive manner. Further research investigating discrete, measureable changes in swallowing pathophysiology would be beneficial to delineate the key factors contributing to impaired swallowing safety and efficiency.

Assessment of swallowing by oropharyngoesophageal scintigraphy in patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is the most common degenerative motor neuron disease in adults, and dysphagia is one of its most frequent and disabling symptoms. Oropharyngoesophageal scintigraphy (OPES) permits a functional and semiquantitative study of the various stages of swallowing. We studied 28 ALS patients (12 females and 16 males; mean age = 63.57 +/- 10.39 yr SD), who were clinically rated against the ALSFRS scale (Amyotrophic Lateral Sclerosis Functioning Rating Scale) and underwent OPES with (99m)Tc-nanocolloid using either a liquid or a semisolid bolus. The semiquantitative parameters we analyzed were Oral Transit Time (OTT), Pharyngeal Transit Time (PTT), Esophageal Transit Time (ETT), Retention Index (RI), and Esophageal Emptying Rate (EER(10s)). Hence, the OPES performed with a semisolid bolus produced a higher proportion of pathologic values for the swallowing variables than when liquid bolus was used. Analyzed by grouping the patients into classes according to their bulbar ALSFRS scores, we found a significant increase in the OTT (p < 0.005), PTT (p < 0.02), and Oropharyngeal Retention Index (OPRI) (p < 0.0004) variables in ALS patients with more severe bulbar involvement. OPES has turned out to be a very important examination for detecting tracheal-bronchial inhalation and it also offers the possibility of acquiring a semiquantitative evaluation of the amount of food inhaled. In our experience, OPES in patients with ALS has been easy to use, economic, well tolerated, and capable of supplying precise indications with regard to the extent of the swallowing disorder, which permits a better clinical definition of the ALS patient.

Manofluorographic evaluation of swallowing in amyotrophic lateral sclerosis and its relationship with clinical evaluation of swallowing

The aim of this cross-sectional study was, first, to identify swallowing dysfunctions in an ALS population of 40 consecutive patients through combined videofluoroscopy and manometry. Secondly, these objective swallowing data were correlated with the functional feeding status as reported by the patient or family member. Videofluoroscopic evaluation showed dysfunctions in the oral phase of swallowing, pharyngeal initiation and pharyngeal transport. In addition, manometric data revealed low tongue driving forces and pharyngeal contraction amplitudes but normal relaxation of the upper oesophageal sphincter (UES). Aspiration was noted in a not negligible number of 9/40 patients. These objective data were then correlated with the clinical swallowing and feeding status, assessed by means of the ALS Swallowing Severity Scale. Patients receiving scores of 6 or lower on the ALSSSS, report dietary consistency changes but are considered 'safe oral feeders'. Nevertheless, our data revealed that these patients showed significant aspiration during videofluoroscopy. Although not every patient with ALS should be referred routinely for radiographic evaluation of swallowing, our findings suggest referral for a radiological examination as soon as the ALSSSS drops to a score of 6 or lower, to evaluate the presence of (silent) aspiration.

Improved infant swallowing after gastroesophageal reflux disease treatment: a function of improved laryngeal sensation?

OBJECTIVE

The objective of this study was to describe improvements in pediatric swallowing after gastroesophageal reflux treatment.

STUDY DESIGN

The authors conducted a retrospective database and chart review at two tertiary care children's hospitals.

PARTICIPANTS

Patients (21 males, 7 females) ranged in age from 1 to 32 months. All patients had clinical evidence of gastroesophageal reflux disease (GERD) as well as evidence of dysphagia with aspiration (laryngeal vestibule and/or trachea) or hypopharyngeal pooling on flexible endoscopic evaluation of swallowing and sensation testing (FEESST) or videofluoroscopic swallow study (VSS).

INTERVENTION

Each child underwent either medical or surgical intervention for control of their GERD.

OUTCOME MEASURES

Outcome measures were change in laryngopharyngeal sensation and swallowing function with repeat swallow evaluation after GERD treatment.

RESULTS

A significant improvement in both swallow function and sensory testing was demonstrated after GERD treatment.

CONCLUSIONS

GERD may result in decreased laryngopharyngeal sensitivity, which may contribute to pediatric swallowing dysfunction. Control of GERD may improve swallow function. These findings have important clinical implications that need further study.

Pathophysiological mechanisms of oropharyngeal dysphagia in amyotrophic lateral sclerosis

We investigated the pathophysiological mechanisms of dysphagia in amyotrophic lateral sclerosis. Forty-three patients with sporadic amyotrophic lateral sclerosis were examined by clinical and electrophysiological methods that objectively measured the oropharyngeal phase of voluntarily initiated swallowing, and these results were compared with those obtained from 50 age-matched control subjects. Laryngeal movements were detected by a piezoelectric sensor and EMG of submental muscles, and needle EMG of the cricopharyngeal muscle of the upper oesophageal sphincter of both the amyotrophic lateral sclerosis and control groups was recorded during swallowing. Amyotrophic lateral sclerosis patients with dysphagia displayed the following abnormal findings. (i) Submental muscle activity of the laryngeal elevators, which produce reflex upward deflection of the larynx during wet swallowing, was significantly prolonged whereas the laryngeal relocation time of the swallowing reflex remained within normal limits. (ii) The cricopharyngeal sphincter muscle EMG demonstrated severe abnormalities during voluntarily initiated swallows. The opening of the sphincter was delayed and/or the closure occurred prematurely, the total duration of opening was shortened and, at times, unexpected motor unit bursts appeared during this period. (iii) During voluntarily initiated swallows there was significant lack of co-ordination between the laryngeal elevator muscles and the cricopharyngeal sphincter muscle. These results point to two pathophysiological mechanisms that operate to cause dysphagia in amyotrophic lateral sclerosis patients. (i) The triggering of the swallowing reflex for the voluntarily initiated swallow is delayed and eventually abolished, whereas the spontaneous reflexive swallows are preserved until the preterminal stage of amyotrophic lateral sclerosis. (ii) The cricopharyngeal sphincter muscle of the upper oesophageal sphincter becomes hyper-reflexic and hypertonic. As a result, the laryngeal protective system and the bolus transport system of deglutition lose their co-ordination during voluntarily initiated swallowing. We conclude that these pathophysiological changes are related mainly to the progressive degeneration of the excitatory and inhibitory corticobulbar pyramidal fibres.