Quantitative Assessment of Swallowing Dysfunction in Patients with Spinal and Bulbar Muscular Atrophy

Rehabilitation of Post-Stroke Swallowing Dysfunction with Repeated Transcranial Magnetic Stimulation RTMS Based on Tomographic Images

In order to study the rehabilitation of dysphagia after stroke, this paper uses tomographic imaging technology and repeated transcranial magnetic stimulation rTMS therapy to verify the effect of this treatment method on the rehabilitation of dysphagia after stroke. In this study, the method of systematic review and meta-analysis are used to comprehensively collect the current published literature on the application of repeated transcranial magnetic stimulation in post-stroke dysphagia, and to quantitatively synthesize and qualitatively analyze the data and opinions. This article aims to explore the therapeutic effect and mechanism of repeated transcranial magnetic stimulation in the treatment of dysphagia after stroke, and to evaluate its effectiveness, so as to better guide the application of repetitive transcranial magnetic stimulation in the rehabilitation of dysphagia after stroke. The evaluation methods of rTMS for the clinical efficacy of PAS, FDS, VDS, DOSS, DD, and BI in patients with dysphagia after stroke are consistent. The influencing factors of rTMS on the swallowing function impairment of stroke include the choice of stimulation frequency, stimulation site, and stimulation time. Low-frequency stimulation of the contralateral hemisphere and high-frequency stimulation of the affected brain can reduce the excitability of the contralateral brain and enhance the excitability of the affected brain. The stimulation site is mainly in the pharyngeal cortex. Experiments show that rTMS can improve swallowing dysfunction after stroke within 2 weeks, and rTMS has no obvious side effects on swallowing dysfunction in patients with cerebral infarction.

Acoustic Change Over Time in Spastic and/or Flaccid Dysarthria in Motor Neuron Diseases

PURPOSE

This study aims to investigate acoustic change over time as biomarkers to differentiate among spastic-flaccid dysarthria associated with amyotrophic lateral sclerosis (ALS), spastic dysarthria associated with primary lateral sclerosis (PLS), flaccid dysarthria associated with spinal and bulbar muscular atrophy (SBMA), and to explore how these acoustic parameters are affected by dysarthria severity.

METHOD

Thirty-three ALS patients with mixed flaccid-spastic dysarthria, 17 PLS patients with pure spastic dysarthria, 18 SBMA patients with pure flaccid dysarthria, and 70 controls, all French speakers, were included in the study. Speakers produced vowel-glide sequences targeting different vocal tract shape changes. The mean and coefficient of variation of the total squared change of mel frequency cepstral coefficients were used to capture the degree and variability of acoustic changes linked to vocal tract modifications over time. Differences in duration of acoustic events were also measured.

RESULTS

All pathological groups showed significantly less acoustic change compared to controls, reflecting less acoustic contrast in sequences. Spastic and mixed spastic-flaccid dysarthric speakers showed smaller acoustic changes and slower sequence production compared to flaccid dysarthria. For dysarthria subtypes associated with a spastic component, reduced degree of acoustic change was also associated with dysarthria severity.

CONCLUSIONS

The acoustic parameters partially differentiated among the dysarthria subtypes in relation to motor neuron diseases. While similar acoustic patterns were found in spastic-flaccid and spastic dysarthria, crucial differences were found between these two subtypes relating to variability. The acoustic patterns were much more variable in ALS. This method forms a promising clinical tool as a diagnostic marker of articulatory impairment, even at mild stage of dysarthria progression in all subtypes.

The Role of Imaging Modalities in Diagnosing Dysphagia: A Clinical Review

Dysphagia, which is characterized by difficulty in oro-gastric bolus transit, is a common condition. It is broadly classified into oropharyngeal or esophageal pathology. A wide array of differentials for dysphagia and initial clinical suspicion of oropharyngeal or esophagus etiology can assist in further evaluation. Fiberoptic endoscopic evaluation of swallowing (FEES) and videofluoroscopic swallow study (VFSS) are the preferred modalities for assessing oropharyngeal bolus transit, residual, as well as determining the risk of laryngeal aspiration. High-resolution pharyngeal manometry (HRPM) is an emerging modality for optimal topographical and pressure assessment of pharyngeal anatomy. HRPM provides improved assistance in evaluating the strength of the pharyngeal muscular contraction. Esophagogastroduodenoscopy (EGD) is the preferred exam for patients with suspected esophageal etiology of dysphagia. Barium swallow provides luminal assessment and assists in evaluating esophageal motility; it is non-invasive, but therapeutic interventions like biopsy cannot be performed. High-resolution esophageal manometry (HREM) has added another dimension in the diagnosis of esophageal motility disorders. The purpose of this review article is to help internists and primary care providers get a better understanding of the role of various imaging modalities in diagnosing dysphagia in the elderly population. This article also provides a comprehensive review and detailed comparison of these imaging modalities based on the latest evidence.

Dysphagia Phenotypes in Spinal Muscular Atrophy: The Past, Present, and Promise for the Future

Purpose The aim of this study was to provide clinicians with an overview of literature relating to dysphagia in spinal muscular atrophy (SMA) to guide assessment and treatment. Method In this clinical focus article, we review literature published in Scopus and PubMed between 1990 and 2020 pertaining to dysphagia in SMA across the life span. Original research articles that were published in English were included. Searches were conducted within four themes of inquiry: (a) etiology and phenotypes, (b) respiratory systemic deficits and management, (c) characteristics of natural history dysphagia and its treatment, and (d) dysphagia outcomes with disease-modifying therapies. Articles for the first two themes were selected by content experts who identified the most salient articles that would provide clinicians foundational background knowledge about SMA. Articles for the third theme were identified using search terms, including spinal muscular atrophy, swallow, dysphagia, bulbar, nutrition, g-tube, alternative nutrition, jaw, mouth, palate, OR mandible. Search terms for the fourth theme included spinal muscular atrophy AND nusinersen OR AVXS-101/onasemnogene abeparvovec-xioi. Review of Pertinent Literature Twenty-nine articles were identified. Findings across identified articles support the fact that patients with SMA who do not receive disease-modifying therapy exhibit clinically significant deficits in oropharyngeal swallow function. Few investigations provided systematic information regarding the underlying physiological deficits responsible for this loss in function, the timing of the degradation, or how disease-modifying therapies change these outcomes. Conclusion Future research outlining the physiological and functional oropharyngeal swallowing deficits among patients with SMA who receive disease-modifying therapy is critical in developing standards of dysphagia care to guide clinicians.

Kennedy's disease: an under-recognized motor neuron disorder

Kennedy's disease or spinal bulbar muscular atrophy is a rare, inherited and slowly progressive multisystem disease mostly manifesting with a motor neuron disease phenotype leading to disability. The slow progression, partial androgen insensitivity, electrophysiological evidence of sensory neuronopathy, and relatively spared central nervous system pathways help differentiate it from amyotrophic lateral sclerosis. To date, there is no treatment or cure with clinical care mainly focused on accurate diagnosis, symptom management, patient education, and genetic counselling.

Maximum bite force in patients with spinal muscular atrophy during the first year of nusinersen therapy - A pilot study

Objectives

Spinal muscular atrophy is a monogenic disease characterized by progressive spinal and bulbar muscle weakness and atrophy. It is caused by the degeneration of alpha-motoneurons. The recent approval of the antisense oligonucleotide nusinersen highlights the need for reliable clinical tools to evaluate motor function in patients with neuromuscular disorders. Measurement of the bulbar neuromuscular function (e.g., bite force) could be an extension to existing motor scales, sensitive to more nuanced changes, especially in symptomatic patients with severely reduced functional abilities.

Materials and methods

Maximum bite force measurement was used to quantify changes of the masticatory function in adult monozygotic female twins with SMA type II. Using piezoelectric transducers, 550 observations were recorded for each patient during the first year of nusinersen therapy.

Results

During the application of four loading doses of nusinersen, bite force levels steadily increased and reached a statistically significantly higher level compared to the initial state in both patients. Subsequent maintenance doses coincided with smaller or no statistically significant changes in maximum bite force.

Conclusions

This pilot study indicates that the measurement of maximum bite force may be a useful tool to detect changes of the bulbar function in SMA patients. As such, it may supplement existing scales to identify treatment-related changes in motor function.

Use of the Penetration-Aspiration Scale in Dysphagia Research: A Systematic Review

The penetration-aspiration scale (PAS) is an 8-point scale used to characterize the depth and response to airway invasion during videofluoroscopy. Though widely used in the field of deglutition, there is a lack of consensus regarding the statistical properties of the scale. In order to better understand the state of the literature and the statistical use of the PAS, a systematic review was undertaken to descriptively examine trends in statistical and reporting practices of the PAS since its inception. Online databases were searched for studies citing the original PAS article, which yielded 754 unique articles. Of these, 183 studies were included in the review. Results showed inconsistencies in the statistical use of the scale; 79 studies treated the PAS as ordinal, 71 as categorical, and 49 as interval. Ten types of categorizations were identified. Reporting of power analyses (9%), as well as inter- (26%) and intra-rater (17%) reliability, was uncommon. Among studies that administered multiple bolus volumes or consistencies, 55% reported PAS analyses at the participant/group level only. This review confirms the existence of discrepancies in the statistical treatment of the PAS. A lack of consensus among researchers limits comparisons between studies. The approach to handling this scale dictates the statistical tests used, potentially affecting results and interpretations. Consistent application of statistically sound approaches to PAS analyses is vital for the future of deglutition research.

Efficacy and safety of leuprorelin acetate for subjects with spinal and bulbar muscular atrophy: pooled analyses of two randomized-controlled trials

BACKGROUND

Spinal and bulbar muscular atrophy (SBMA) is an adult-onset, hereditary neuromuscular disease characterized by muscle atrophy, weakness, contraction fasciculation, and bulbar involvement. Although the causative gene, androgen receptor, has been identified, the development of novel therapeutics for SBMA is incomplete. In this study, the efficacy and safety of leuprorelin acetate administration for patients with SBMA, using the pooled data of two randomized-controlled trials, was studied.

METHODS

Two randomized double-blinded studies (JASMITT-06DB and JASMITT-11DB) were done as multicentric, investigator-initiated clinical trials in Japan. In both studies, eligible patients were randomly assigned 1:1 to receive leuprorelin acetate administration once per 12 weeks for 48 weeks. The primary endpoint was the longitudinal change of pharyngeal barium residues from the baseline data measured with videofluorographic swallowing analyses. The pooled analysis plan was decided upon after the 06B study was finished and before the 11DB study began.

RESULTS

The primary endpoint difference between the leuprorelin group and the placebo group was pharyngeal barium residue after initial swallowing, - 4.12% (95% CI, - 8.40-0.15; p = 0.058). The primary endpoint of this study does not reach significant results, although inter-group differences of pharyngeal barium residues after the initial swallowing indicated that leuprorelin acetate may be effective at each assessment point in both study groups.

CONCLUSIONS

The efficacy of leuprorelin acetate for patients with SBMA was statistically similar in two randomized-controlled trials, and suggested that leuprorelin acetate may be effective and safe. Further investigations are needed to clarify the promising efficacy of the drug.

Biomarkers of Spinal and Bulbar Muscle Atrophy (SBMA): A Comprehensive Review

Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy's disease, is a rare, X-linked, late onset neuromuscular disorder. The disease is caused by a CAG trinucleotide repeat expansion in the first exon of the androgen receptor gene. It is characterized by slowly progressive lower motor neurons degeneration, primary myopathy and widespread multisystem involvement. Respiratory involvement is rare, and the condition is associated with a normal life expectancy. Despite a plethora of therapeutic studies in mouse models, no effective disease-modifying therapy has been licensed for clinical use to date. The development of sensitive monitoring markers for the particularly slowly progressing pathology of SBMA is urgently required to aid future clinical trials. A small number of outcome measures have been proposed recently, including promising biochemical markers, which show correlation with clinical disability and disease-stage and progression. Nevertheless, a paucity of SBMA-specific biomarker studies persists, delaying the development of monitoring markers for pharmaceutical trials. Collaborative efforts through international consortia and multicenter registries are likely to contribute to the characterization of the natural history of the condition, the establishment of disease-specific biomarker panels and ultimately contribute to the development of disease-modifying drugs.