Oral Motor Movements and Swallowing in Patients with Myotonic Dystrophy Type 1

Best practice recommendations for speech-language pathology in children with neuromuscular disorders: A Delphi-based consensus study

PURPOSE

Speech-language pathology (SLP) is considered an essential intervention due to the high prevalence of dysphagia and dysarthria in paediatric neuromuscular disorders (pNMD). Evidence-based guidelines for SLP in pNMD are missing and children could be deprived the best of care. This study aimed to achieve consensus and present best practice recommendations on SLP intervention in pNMD.

METHOD

A modified Delphi technique was used with a panel of experienced Dutch speech-language pathologists. In two online survey rounds and a face-to-face consensus meeting, the SLP experts proposed intervention items for cases of four types of pNMD (congenital myopathy, Duchenne muscular dystrophy, myotonic dystrophy type 1, and spinal muscular atrophy type 2), covering symptoms of dysphagia, dysarthria, drooling, and oral hygiene problems. They rated the level of agreement.

RESULT

Intervention items that achieved consensus were incorporated into best practice recommendations. These recommendations cover six core intervention components (wait and see, explanation and advice, training and treatment, aids and adjustments, referral to other disciplines, and monitoring) suitable for the described symptoms.

CONCLUSION

Insight into treatment options is essential to facilitate speech-language pathologists in clinical decision-making. The current study led to best practice recommendations for speech-language pathologists working within the field of pNMD.

Alteraciones del habla y deglución en pacientes con distrofia muscular: una revisión sistemática

La distrofia muscular corresponde a un grupo heterogéneo de alteraciones musculares de origen genético. El propósito de esta revisión fue describir las principales alteraciones del habla y deglución que presentan los pacientes con distrofia muscular. Se realizó una búsqueda electrónica de artículos relevantes en el área, los cuales incluyeron en su descripción pacientes con distrofia muscular asociadas a trastornos del habla y/o deglución. Las bases de datos revisadas fueron EMBASE, CINAHL, PubMed, PsycInfo, Web of Science y Scopus. Se encontraron 15 estudios que cumplieron con los criterios de inclusión, involucrando un total de 526 participantes con un promedio de edad de 43,09 años. 12/15 estudios incluyeron medidas de deglución y/o alimentación y 3/15 incluyeron evaluación del habla. La revisión evidencia gran variabilidad en los instrumentos utilizados para describir las alteraciones del habla y deglución.  En las distrofias musculares incluidas en la presente revisión se observó alteración principalmente en la etapa faríngea y dificultad en la formación del bolo asociado a alteraciones en la oclusión y fuerza muscular. El habla es un parámetro poco estudiado en este tipo de condición.

Web version of the protocol of the orofacial myofunctional evaluation with scores: usability and learning

PURPOSE

The Orofacial Myofunctional Evaluation with Scores (OMES) protocol has been validated and used in clinical practice and research. The goals of this study were to develop, analyze and improve a version of OMES for the Web and to investigate the relationship between the usability judgments and the prior experience of the evaluators and whether using the interface promotes learning, as shown by the task completion time (TCT).

METHODS

Study steps: 1) inspection of the prototype by the team; 2) evaluation of usability by three experienced speech-language pathologists (SLPs); and 3) evaluation of its usability by 12 SLPs with varying levels of experience in the use of OMES. Participants answered the Heuristic evaluation (HE), the Computer System Usability Questionnaire (CSUQ), and expressed free comments. The TCT was recorded.

RESULTS

The OMES-Web reached excellent usability levels, and the participants were highly satisfied. The correlations between the participants' experience and the HE and CSUQ scores were not significant. The TCT decreased significantly throughout the tasks.

CONCLUSION

OMES-Web meets the usability criteria, and participants feel satisfied with the system regardless of their level of experience. The fact that it is easy to learn favors its adoption by professionals.

Effect of Volitional Effort on Submental Surface Electromyographic Activity During Healthy Swallowing

The effortful swallowing technique aims to compensate for or rehabilitate impaired swallowing by using maximal volitional effort to behaviorally modify aspects of swallowing physiology. Given that swallowing is a submaximal task, swallowing at submaximal levels has recently been suggested as a more task-specific therapeutic technique. The aim of this study was to investigate differences in muscle activity during minimum, regular, and maximum effort swallowing of different boluses and across different ages, with the goal of characterizing the task specificity of minimum effort and maximum effort swallowing. Forty-three healthy adults (22 female) representing four age groups (20-39, 40-59, 60-79, and 80 + years) participated in the study. They were verbally cued to swallow saliva and 5 mL water boluses using participant-determined minimum, regular, and maximum levels of effort, in randomized order. sEMG peak amplitude and duration of each swallow were measured. Linear mixed effects analyses demonstrated that compared to regular effort swallowing, maximum effort swallowing resulted in increased sEMG amplitude (p < .001) and prolonged duration (p < .001), while minimum effort swallowing resulted in decreased amplitude (p < .001) but no significant difference in duration (p = .06). These effects occurred regardless of age or bolus type. Differences in sEMG activity were smaller between regular and minimum effort swallowing than regular and maximum effort swallowing. Both increasing and decreasing volitional efforts during swallowing translate to significant modulation of muscle activity. However, regular swallowing is more similar to minimal effort swallowing. Results reinforce the concept of swallowing as a submaximal task, and provide insight into the development of sEMG biofeedback techniques for rehabilitation.

The relationship between pulmonary and swallowing functions in patients with neuromuscular diseases followed up by a tertiary referral center: a cross-sectional study

INTRODUCTION

Respiratory muscle weakness is common in patients with neuromuscular diseases (NMD). This puts them at risk for dysphagia and other pulmonary complications.

OBJECTIVES

To investigate the relationship between pulmonary function and swallowing in NMD.

MATERIALS AND METHODS

In this cross-sectional study, medical records of patients undergoing treatment at the Tertiary Referral Center for Neuromuscular Diseases of Hospital de Apoio de Brasília, Brazil, were reviewed. Respiratory function was assessed through spirometry (FVC and FEV1 measured) and swallowing assessed by the Dysphagia Risk Evaluation Protocol and the Functional Oral Intake Scale.

RESULTS

Two hundred and twenty-two patients were included. Dysphagia was present in 46.8% of patients and impairment of pulmonary function in 64.0%. The mean FVC observed was 66.9% and FEV1 was 66.0%, indicating restrictive lung disease. A correlation between the decline of pulmonary and swallowing functions was observed in patients with NMDs (FVC vs. DREP, R = 0.46; FVC vs. FOIS, R = 0.42; FEV1 vs. DREP, R = 0.42; FEV1 vs. FOIS, R = 0.40, p<.01). FVC and FEV1 values tend to be lower in patients with dysphagia in the context of NMD.

CONCLUSIONS

A positive correlation between pulmonary function and swallowing outcomes was observed in patients with NMD. Despite respiratory and swallowing impairment being widely present in the population with NMD, they require different treatments according to the disease's pathophysiology. Future studies should be conducted to explore the disease-specific relationship between pulmonary function and swallowing in patients with NMD.

Brazilian manuscripts published in the Dysphagia journal

ABSTRACT Objective: to survey the Brazilian participation in original and review articles published in the Dysphagia journal. Methods: original and review articles in volumes 1 to 35, quantifying all those developed in Brazil, the diseases researched, the places where the investigations were conducted, and the number of citations they received, were analyzed. The categorical variables are presented in relative and absolute frequencies. Literature Review: a total of 35 Brazilian manuscripts were published. The most researched disease was Parkinson’s, followed by Chagas disease, stroke, and the physiology of swallowing. The highest number of publications was carried out at the Universidade de São Paulo, campus at Ribeirão Preto, SP, and the Universidade Federal de São Paulo, capital city. Between 2001 and 2010, 14 manuscripts were published (3.7% of the journal), and between 2011 and 2020, 20 were published (2.9% of the journal). By 2019, the manuscripts had received 481 citations - 17 citations per article between 1998 and 2009, and 14, between 2010 and 2019. Conclusion: Brazilian manuscripts are regularly published in the Dysphagia journal and have a scientific impact. However, there has not been a progressive increase in the number of published articles.

Orofacial Motor Functions and Temporomandibular Disorders in Patients With Sjögren's Syndrome

OBJECTIVE

Sjögren's syndrome (SS) induces difficulty in chewing and swallowing due to low salivary flow. However, these symptoms may be associated with other factors, such as orofacial myofunctional disorders and temporomandibular disorder (TMD), which have not been comprehensively assessed in this population. The aims of this study were to investigate orofacial muscles and functions as well as the presence of TMD in patients with SS compared with a group without SS and to analyze whether the patients' experience of limitations in orofacial functioning is associated with the orofacial functional status and muscle pain related to TMD.

METHODS

Women with SS based on the 2002 American-European Consensus Group criteria and volunteers paired by age and sex were compared. The examinations included the orofacial myofunctional evaluation with scores (OMES) protocol, tongue and lip strength measures, and electromyography of the masticatory muscles. TMD investigations included clinical examination, self-report of symptoms, and assessment according to the Jaw Functional Limitation Scale.

RESULTS

Patients with SS present with impaired muscle and orofacial functions based on lower scores of all categories of OMES (P < 0.0001), tongue strength (P = 0.0003-0.0004), and masticatory muscle activity (P = 0.0002-0.007), as well as worse TMD signs and symptoms (P < 0.05) and jaw functional limitation (P < 0.0001-0.0003).

CONCLUSION

Patients' experiences with limitation in mastication and swallowing were associated with orofacial myofunctional status and muscle pain related to TMD. Those disorders should be monitored along with disease control and must be addressed in the clinical evaluation to prevent nutritional and metabolic comorbidities in patients with SS.

Consensus-Based Care Recommendations for Pulmonologists Treating Adults with Myotonic Dystrophy Type 1

PURPOSE OF REVIEW

Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects approximately 1 in 2,500 individuals globally [Ashizawa et al.: Neurol Clin Pract 2018;8(6):507-20]. In patients with DM1, respiratory muscle weakness frequently evolves, leading to respiratory failure as the main cause of death in this patient population, followed by cardiac complications [de Die-Smulders et al.: Brain 1998;121(Pt 8):1557-63], [Mathieu et al.: Neurology 1999;52(8):1658-62], [Groh et al.: Muscle Nerve 2011;43(5):648-51]. This paper provides a more detailed outline on the diagnostic and management protocols, which can guide pulmonologists who may not have experience with DM1 or who are not part of a neuromuscular multidisciplinary clinic. A group of neuromuscular experts in DM1 including pulmonologists, respiratory physiotherapists and sleep specialists discussed respiratory testing and management at baseline and during follow-up visits, based on their clinical experience with patients with DM1. The details are presented in this report.

RECENT FINDINGS

Myotonic recruited 66 international clinicians experienced in the treatment of people living with DM1 to develop and publish consensus-based care recommendations targeting all body systems affected by this disease [Ashizawa et al.: Neurol Clin Pract. 2018;8(6):507-20]. Myotonic then worked with 12 international respiratory therapists, pulmonologists and neurologists with long-standing experience in DM respiratory care to develop consensus-based care recommendations for pulmonologists using a methodology called the Single Text Procedure. This process generated a 7-page document that provides detailed respiratory care recommendations for the management of patients living with DM1. This consensus is completely based on expert opinion and not backed up by empirical evidence due to limited clinical care data available for respiratory care management in DM patients. Nevertheless, we believe it is of relevance for professionals treating adults with myotonic dystrophy because it addresses practical issues related to respiratory management and care, which have been adapted to meet the specific issues in patients with DM1.

SUMMARY

The resulting recommendations are intended to improve respiratory care for the most vulnerable of DM1 patients and lower the risk of untoward respiratory complications and mortality by providing pulmonologist who are less experienced with DM1 with practical indications on which tests and when to perform them, adapting the general respiratory knowledge to specific issues related to this multiorgan disease.

The effect of incentive spirometer training on oromotor and pulmonary functions in children with Down's syndrome

Objectives

This study investigated the effect of incentive spirometry training on oromotor and pulmonary functions in children with Down's syndrome.

Methods

Thirty-four children with Down's syndrome were randomly divided into two groups; the children were of both sexes and aged between 6 and 12 years. Group A received only oromotor exercises, while Group B received oromotor exercises and incentive spirometry training. The pulmonary function test was performed using computerized spirometry model master screen that assessed pulmonary functions (peak expiratory flow, forced vital capacity, and forced expiratory volume in 1s), while the orofacial myofunctional evaluation with score (OMES) was used to evaluate oromotor function before and after treatment.

Results

The post treatment results showed significant difference in oromotor and pulmonary functions within both groups, but no significant differences were found between the two groups.

Conclusions

Oromotor exercises are more effective than incentive spirometry training in improving both pulmonary and oromotor functions in children with Down's syndrome.

Oropharyngeal dysphagia in early stages of myotonic dystrophy type 1

INTRODUCTION

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder characterized mainly by skeletal muscle alterations. Although oropharyngeal dysphagia is a prominent clinical feature of DM1, it remains poorly studied in its early disease stages.

METHODS

Dysphagia was investigated in 11 presymptomatic DM1 carriers, 14 patients with DM1 and 12 age-matched healthy controls, by using fiberoptic endoscopic evaluation of swallowing (FEES) and clinical scores.

RESULTS

Scores for the FEES variables, delayed pharyngeal reflex, posterior pooling, and postswallow residue were significantly greater in patients with DM1 and in presymptomatic DM1 carriers than in healthy controls (P < 0.05); oropharyngeal dysfunction was more severe in patients than in presymptomatic carriers. Penetration/aspiration was found altered exclusively in patients with DM1 (P < 0.05).

DISCUSSION

Swallowing dysfunction occurs in presymptomatic DM1 carriers. Timely diagnosis of dysphagia in preclinical stages of the disease will aid in the timely management of presymptomatic carriers, potentially preventing medical complications. Muscle Nerve, 2019.

Core Clinical Phenotypes in Myotonic Dystrophies

Myotonic dystrophy type 1 (DM1) and type 2 (DM2) represent the most frequent multisystemic muscular dystrophies in adulthood. They are progressive, autosomal dominant diseases caused by an abnormal expansion of an unstable nucleotide repeat located in the non-coding region of their respective genes DMPK for DM1 and CNBP in DM2. Clinically, these multisystemic disorders are characterized by a high variability of muscular and extramuscular symptoms, often causing a delay in diagnosis. For both subtypes, many symptoms overlap, but some differences allow their clinical distinction. This article highlights the clinical core features of myotonic dystrophies, thus facilitating their early recognition and diagnosis. Particular attention will be given to signs and symptoms of muscular involvement, to issues related to respiratory impairment, and to the multiorgan involvement. This article is part of a Special Issue entitled “Beyond Borders: Myotonic Dystrophies—A European Perception.”

Orofacial Myofunctional Evaluation Protocol for older people: validity, psychometric properties, and association with oral health and age

PURPOSE

To develop a comprehensive assessment protocol for identifying, classifying and grading changes in stomatognathic system components and functions of older people, to determine its psychometric properties and verify its association with oral health and age.

METHODS

The content validity of the Orofacial Myofunctional Evaluation with Scores for Elders protocol (OMES-Elders) was established based on the literature. The protocol contains three domains: appearance/posture, mobility, and functions of the stomatognathic system. Eighty-two healthy elder volunteers (mean age 69±7.24 years) were evaluated using the OMES-Elders. A test-screening for orofacial disorders (reference) was used to analyze the concurrent validity (correlation test), sensitivity, specificity and accuracy (Receiver Operating Characteristic Curve: ROC curve) of the OMES-Elders. The association of the OMES-Elders scores with the Oral Health Index (OHX) and age in the sample was tested.

RESULTS

There was a significant correlation between the OMES-Elders and the reference test (p < 0.001). Reliability coefficients ranged from good (0.89) to excellent (0.99). The OMES-Elders protocol had a sensitivity of 82.9%, specificity of 83.3% and accuracy of 0.83. The scores of the protocol were significantly lower in individuals with worse oral health (OHX ≤ 61%), although individuals with adequate oral health (OHX ≥ 90%) also had myofunctional impairments. The predictors OHX and age explained, respectively, 33% and 30% of the variance in the OMES-Elders total score.

CONCLUSION

As the first specific orofacial myofunctional evaluation of older people, the OMES-Elders protocol proved to be valid, reliable and its total score was associated with oral health and age.

Surgical Orthodontic Treatment of a Patient Affected by Type 1 Myotonic Dystrophy (Steinert Syndrome)

Myotonic dystrophy, or Steinert's disease, is the most common form of muscular dystrophy that occurs in adults. This multisystemic form involves the skeletal muscles but affects also the eye, the endocrine system, the central nervous system, and the cardiac system. The weakness of the facial muscles causes a characteristic facial appearance frequently associated with malocclusions. Young people with myotonic dystrophy, who also have severe malocclusions, have bad oral functions such as chewing, breathing, and phonation. We present a case report of a 15-year-old boy with anterior open bite, upper and lower dental crowding, bilateral crossbite, and constriction of the upper jaw with a high and narrow palate. The patient's need was to improve his quality of life. Because of the severity of skeletal malocclusion, it was necessary to schedule a combined orthodontic and surgical therapy in order to achieve the highest aesthetic and functional result. Although therapy caused an improvement in patient's quality of life, the clinical management of the case was hard. The article shows a balance between costs and benefits of a therapy that challenges the nature of the main problem of the patient, and it is useful to identify the most appropriate course of treatment for similar cases.

A comparison of swallowing dysfunction in Becker muscular dystrophy and Duchenne muscular dystrophy

PURPOSE

Swallowing dysfunction has been reported in Duchenne muscular dystrophy (DMD), but has not been studied in Becker muscular dystrophy (BMD). The aims of this study were to report the characteristics of swallowing dysfunction in BMD compared with DMD.

MATERIALS AND METHODS

The study participants were 18 patients with BMD and 18 patients with DMD. All the patients were examined using videofluorography during swallowing of 5 mL of fluid. The penetration-aspiration scale (P-A scale) and the videofluorographic dysphagia scale (VDS) were used to evaluate dysphagia.

RESULTS

Swinyard functional ability stage was not significantly different between the BMD and DMD groups. Rate of aspiration, P-A scale score, and total VDS score did not differ across groups, but the VDS item score for laryngeal elevation was lower in the BMD group than in the DMD group (median scores 4.5 and 9, respectively; p < 0.001). In the BMD group, total VDS score significantly correlated with Swinyard stage (r = 0.78, p < 0.001), but not with age or lung function.

CONCLUSION

Patients with BMD have swallowing problems similar to those observed in patients with DMD when matched according to physical functional status. These patients should be evaluated and followed-up for the duration of their disease. Implications for rehabiliation Dysphagia is one of the most critical problems in patients with progressive neuromuscular disease but dysphagia in patients with Becker muscular dystrophy (BMD) was not well known. Eighteen patients with BMD and 18 patients with Duchenne muscular dystrophy were examined with videofluorography. Patients with BMD have swallowing problems similar to those observed in patients with DMD.

Six Serum miRNAs Fail to Validate as Myotonic Dystrophy Type 1 Biomarkers

Myotonic dystrophy type 1 (DM1) is an autosomal dominant genetic disease caused by expansion of a CTG microsatellite in the 3' untranslated region of the DMPK gene. Despite characteristic muscular, cardiac, and neuropsychological symptoms, CTG trinucleotide repeats are unstable both in the somatic and germinal lines, making the age of onset, clinical presentation, and disease severity very variable. A molecular biomarker to stratify patients and to follow disease progression is, thus, an unmet medical need. Looking for a novel biomarker, and given that specific miRNAs have been found to be misregulated in DM1 heart and muscle tissues, we profiled the expression of 175 known serum miRNAs in DM1 samples. The differences detected between patients and controls were less than 2.6 fold for all of them and a selection of six candidate miRNAs, miR-103, miR-107, miR-21, miR-29a, miR-30c, and miR-652 all failed to show consistent differences in serum expression in subsequent validation experiments.

Translation and cross-cultural adaptation of the protocol of orofacial myofunctional evaluation with scores for Italian Language

The protocol of orofacial myofunctional evaluation with scores (OMES-protocol or AMIOFE in Portuguese language) is a validated instrument for the diagnosis of orofacial myofunctional disorders that can be used in clinical practice for speech-language pathologists. Because in the Italian language there is no validated tool for such purpose, this study was developed.

PURPOSES

To translate and culturally adapt the OMES-protocol for Italian language and determine the normal score value in a group of young Italian adults.

METHODS

The OMES-protocol was translated from English to Italian by three bilingual individuals. From these translations, a consensus version was prepared by a research committee (three speech therapists and one physician and submitted to a committee of judges composed by eight speech therapists experienced in the area. The authors of the original version verified and approved the Italian version of the protocol. The instrument was tested via evaluations of 40 young and grown-up Italians (age range: 18-56 years) performed by two speech therapists. A cutoff score, previously described, was used to determine the mean and standard deviation.

RESULTS

The translation stage and the final Italian version of the OMES-protocol are shown. The mean of scores for individuals with and without orofacial myofunctional disorders were presented.

CONCLUSION

The Italian version of the OMES-protocol was developed, translated, and cross-culturally adapted. Normal values for young and adult Italian subjects are presented.

Muscle wasting in myotonic dystrophies: a model of premature aging

Myotonic dystrophy type 1 (DM1 or Steinert’s disease) and type 2 (DM2) are multisystem disorders of genetic origin. Progressive muscular weakness, atrophy and myotonia are the most prominent neuromuscular features of these diseases, while other clinical manifestations such as cardiomyopathy, insulin resistance and cataracts are also common. From a clinical perspective, most DM symptoms are interpreted as a result of an accelerated aging (cataracts, muscular weakness and atrophy, cognitive decline, metabolic dysfunction, etc.), including an increased risk of developing tumors. From this point of view, DM1 could be described as a progeroid syndrome since a notable age-dependent dysfunction of all systems occurs. The underlying molecular disorder in DM1 consists of the existence of a pathological (CTG) triplet expansion in the 3′ untranslated region (UTR) of the Dystrophia Myotonica Protein Kinase (DMPK) gene, whereas (CCTG)n repeats in the first intron of the Cellular Nucleic acid Binding Protein/Zinc Finger Protein 9(CNBP/ZNF9) gene cause DM2. The expansions are transcribed into (CUG)n and (CCUG)n-containing RNA, respectively, which form secondary structures and sequester RNA-binding proteins, such as the splicing factor muscleblind-like protein (MBNL), forming nuclear aggregates known as foci. Other splicing factors, such as CUGBP, are also disrupted, leading to a spliceopathy of a large number of downstream genes linked to the clinical features of these diseases. Skeletal muscle regeneration relies on muscle progenitor cells, known as satellite cells, which are activated after muscle damage, and which proliferate and differentiate to muscle cells, thus regenerating the damaged tissue. Satellite cell dysfunction seems to be a common feature of both age-dependent muscle degeneration (sarcopenia) and muscle wasting in DM and other muscle degenerative diseases. This review aims to describe the cellular, molecular and macrostructural processes involved in the muscular degeneration seen in DM patients, highlighting the similarities found with muscle aging.

Evaluation of malnutrition in patients with nervous system disease

Nutritional deficiencies are independent risk factors for adverse outcomes in patients with nervous system disease. Patients with nervous system disease can often become malnourished due to swallowing difficulties or unconsciousness. This malnourishment increases hospitalization duration; average total hospital cost; occurrence of infection, pressure ulcers, and other complications. These problems need to be addressed in the clinic. In this paper, we review the relevant literature, including studies on influencing factors, evaluations, indexes, and methods: Our aim is to understand the current status of malnutrition in patients with nervous system disease and reasons associated with nutritional deficiencies by using malnutrition evaluation methods to assess the risk of nutritional deficiencies in the early stages.

Swallowing assessment in myotonic dystrophy type 1 using fiberoptic endoscopic evaluation of swallowing (FEES)

This study describes the swallowing function of patients with myotonic dystrophy type 1 (DM1) and the effect of bolus consistency on swallowing in this group. The aim of the study is twofold: (a) to identify which (and to what extent) swallowing variables change for DM1 patients relative to healthy control subjects and (b) to examine whether the degree of oropharyngeal dysphagia is associated with disease severity. Forty-five consecutive DM1 patients and ten healthy subjects underwent a swallowing assessment, at Maastricht University medical Center in the Netherlands. The assessment included a standardized fiberoptic endoscopic evaluation of swallowing (FEES) protocol using different bolus consistencies. Clinical severity of the disease was assessed using the muscular impairment rating scale (MIRS). Significant differences were found between patients and controls for all FEES variables. The magnitude of these differences depended on the bolus consistency. The odds of a more pathological swallowing outcome increased significantly with higher MIRS levels. In conclusion, swallowing function is found to be significantly altered in DM1 patients. The results emphasize the importance of conducting a detailed swallowing assessment in all patients, even those with mild muscle weakness.