Dysphagia is present but mild in myotonic dystrophy type 2

The phenotype of myotonic dystrophy type 2 (DM2) shows similarities as well as differences to that of myotonic dystrophy type 1 (DM1). Dysphagia, a predominant feature in DM1, has not yet been examined in DM2. In a recent nationwide questionnaire survey of gastrointestinal symptoms in DM2, 12 out of 29 DM2 patients reported to have difficulty in swallowing for solid food. The aim of the study was to investigate the presence of dysphagia in patients with genetically proven DM2 who reported difficulty in swallowing for solid food at the questionnaire survey. Swallowing function and fiberoptic endoscopic evaluation of swallowing (FEES) were examined by a speech therapist and otorhinolaryngologist, respectively. In DM2 patients who reported difficulty in swallowing the presence of dysphagia could be confirmed (clinically in 100%, by FEES in 88%). A correlation exists between Dysphagia Outcome and Severity Score (DOSS) and age (p = 0.05). None of the patients was underweight, and none of the patients had suffered aspiration pneumonia in the past. Dysphagia is present among DM2 patients and is more severe in older patients. However, dysphagia is generally mild, and do not lead to weight loss, or aspiration pneumonia.     

Reproducibility and reaction time of swallowing as markers of dysphagia in parkinsonian syndromes

ObjectiveTo investigate reproducibility and reaction time of oropharyngeal swallowing in patients with Parkinson’s disease (PD) and atypical parkinsonisms (APs).MethodsWe enrolled 19 patients with PD, 30 with APs, and 20 healthy subjects. Presence and severity of dysphagia were assessed with clinical and fiberoptic endoscopic evaluations of swallowing.Reproducibility of the oral and pharyngeal phases of swallowing were respectively assessed by calculating the ‘similarity index’ of the electromyography activity of the submental/suprahyoid muscles and of the laryngeal-pharyngeal mechanogram during consecutive swallows. These were performed both ‘on command’ and spontaneously. The swallowing reaction time was also recorded.ResultsReproducibility of the oral phase of swallowing was reduced in patients with dysphagia, mainly when swallowing ‘on command’. Swallowing reaction time was prolonged in dysphagic patients. These electrophysiological parameters did not vary among different parkinsonian syndromes and correlated with dysphagia severity.ConclusionsIncreased variability of oral swallowing automatisms and abnormal sensorimotor integration may be of relevance for the pathophysiology of dysphagia in parkinsonian syndromes.SignificanceThe electrophysiological assessment represents a valuable tool to investigate swallowing alterations in parkinsonian syndromes. It may also provide useful insights into clinical severity and pathophysiology of dysphagia, giving clues for the choice of the best therapeutic approach.     

纤维鼻咽喉镜吞咽功能检查对脑卒中后吞咽障碍的诊断价值

目的 评价纤维鼻咽喉镜吞咽功能检查(fiberoptic endoscopic examination of swallowing,FEES)对于脑卒中后吞咽障碍的诊断价值.方法 对22例急性脑梗死患者进行吞钡电视透视(videofluoroseopy,VF)检查和FEES.以VF检查为金标准,计算FEES对于急性脑卒中患者误吸、渗漏、穿透和潴留诊断的灵敏度、特异度、阳性预测值和阴性预测值.结果 FEES对于穿透诊断的灵敏度为83.3%,特异度为90.0%;对误吸诊断的灵敏度、特异度均为90.9%;对潴留诊断的灵敏度为100%,特异度为77.8%;对渗漏诊断的灵敏度为73.3%,特异度为71.4%.结论 FEES对于急性脑卒中患者穿透、误吸和潴留诊断的可靠性较好,是评估脑卒中后吞咽障碍的有力工具.     

Oropharyngeal dysphagia in polymyositis/dermatomyositis

The nature of the oropharyngeal dysphagia in polymyositis/dermatomyositis (PM/DM) has been investigated by EMG methods. Nineteen patients with PM/DM were studied. The oropharyngeal phase of swallowing was evaluated by the electrophysiological methods measuring the laryngeal relocation time, pharyngeal transit time and the triggering of the pharyngeal phase of swallowing reflex. The EMG of cricopharyngeal muscle of the upper esophageal sphincter was also recorded in 10 patients. The patients have been compared with a group of 22 healthy controls matched with age and gender. Dysphagia limit was also measured for all patients and control subjects. Fourteen out of 19 patients could not swallow 20 ml or less amount of water at one go and divided the bolus into two or more pieces (piecemeal deglutition) in comparison to normal subjects. In PM/DM patients, the triggering of the swallowing reflex for the voluntarily initiated swallow was normal while the pharyngeal phase of swallowing was significantly prolonged. The cricopharyngeal sphincter muscle EMG demonstrated severe abnormalities in halves of the patients investigated. These findings demonstrated the weakness of the striated oropharyngeal muscles. Cricopharyngeal sphincter muscle was affected less frequently and showed either hyperreflexic or hyporeflexic states during swallowing. It is concluded that the pharyngeal stage of oropharyngeal swallowing is mainly involved in patients with PM/DM.     

Assessment of a disease-specific muscular impairment rating scale in myotonic dystrophy

OBJECTIVE: To document the intra/interrater reliability and the construct validity of the Muscular Impairment Rating Scale (MIRS) in assessing patients with myotonic dystrophy type 1 (DM1). The MIRS is a ordinal five-point rating scale, established in accordance with the clinically recognized distal to proximal progression of the muscular involvement in DM1, based partly on a manual muscle testing (MMT) of 11 muscle groups. METHODS: To assess the reliability of the MIRS, 55 patients with DM1 were examined by three different observers, one of them evaluating each patient twice. Intra- and interobserver reliability of the MIRS was measured using Cohen's weighted kappa. To assess the construct validity of the MIRS, correlations were made with the Functional Status Index (FSI) and eight timed functional tasks. RESULTS: The intraobserver reliability of the MIRS was excellent (weighted kappa = 0.84), and the interobserver reliability was interpreted as a substantial agreement (weighted kappa = 0.77 to 0.79). The correlation coefficients between MMT scores and MIRS grades were all highly significant (r(s) = -0.81 to -0.88, p < 0.001). The FSI showed a significant progressive increase of the total median dependence score in activities of daily living from 0 in MIRS grade 1 to 39 in MIRS grade 5 (p < 0.001). The time needed to perform the eight functional tasks was also found to significantly increase in relation with the progression of the MIRS grades. CONCLUSION: The MIRS is a quick, simple, and reliable measurement of muscular impairment in DM1. The FSI questionnaire and the timed motor activities supported its construct validity. The MIRS is useful to monitor major stages of DM1 progression, to study the natural history of the disease, and to identify homogeneous groups of patients for clinical trials.     

A combined approach of bedside clinical examination and flexible endoscopic evaluation of swallowing in poststroke dysphagia: A pilot study

Background:

As with most neurologic conditions, stroke involves impairment of the swallowing mechanism. This could be a spectrum of issues, the worst of which is aspiration. At the same time, the prolonged presence of a naso-gastric tube (NGT) has its own morbidity. Flexible endoscopic evaluation of swallowing (FEES) is one reliable method to assess the structural and functional status of the oropharynx and larynx, during the swallowing process.

Objective:

To study the utility of FEES in decision-making with respect to resumption of oral intake in stroke patients. To document the findings of FEES in stroke patients, and to look for correlations between these and the site of stroke.

Materials and Methods:

Protocol insertion of naso-gastric tube in all stroke patients, at presentation. Initial assessment by a neurologist and swallowing therapist, depending on cognitive status of the patient. All patients underwent MRI Brain with diffusion weighted sequences. After detailed clinical examination, they underwent swallow exercises under the supervision of a trained swallowing therapist. The decision to remove NGT was taken clinically by the combined decision of neurologist and swallowing therapist. Then all patients underwent FEES by the ENT surgeon. The final decision for NGT removal was taken as per the FEES findings.

Result:

Sixteen stroke patients underwent the FEES procedure during a period of six months. The oropharyngeal and laryngeal findings varied depending on the area of stroke involvement. Of these, change in decision regarding swallowing rehabilitation or NGT removal was needed in four patients, following the FEES findings.

Conclusions:

FEES is an easy, efficient and reliable method to evaluate the swallowing status in stroke patients. In combination with good bedside clinical examination and swallow exercises, it can be a good tool in assessing patients with post- stroke dysphagia. Post-stroke rehabilitation and prevention of aspiration pneumonia can be effectively done with the help of FEES.     

Brain involvement in myotonic dystrophies: neuroimaging and neuropsychological comparative study in DM1 and DM2

The objective of this study was to determine the degree of brain involvement in a cohort of myotonic dystrophy type 1 and type 2 (DM1, DM2) patients by brain studies and functional tests and to compare the results of the two groups. DM1, DM2 are multisystemic disorders due to polynucleotide expansions. Previous studies on brain involvement by neuroimaging and functional methods have led to contradictory results. Fifty molecularly defined DM1 patients and 14 DM2 patients, were recruited for the study. Age at recruitment, age at disease onset, disease duration and educational level were recorded. Neuromuscular assessment was done by MIRS. An extensive neuropsychological battery was performed in 48/50 DM1 and in a control group of 44 healthy matched subjects. Forty six of 50 DM1 and 12/14 DM2 underwent brain MRI; 21/50 DM1 and 9/14 DM2 underwent brain perfusion SPECT, with semiquantitative analysis of the results. MRI images were classified by ARWMC (age-related white matter changes) score, in order to quantify recurrence, localization and patterns of distribution of white matter hyperintense lesions (WMHLs) in our two cohorts. MRI results were matched to SPECT and to neuropsychological results. Thirty-seven of 46 DM1 and 10/12 DM2 had abnormal MRI imaging, showing scattered supratentorial, bilateral, symmetrical focal or diffuse WMHLs. A typical temporo-insular diffuse subcortical pattern was seen in DM1 subjects only, with no correlation with cognitive involvement. Major cognitive involvement was seen in the case of diffuse frontal lesions. A relationship with CTG expansion size was documented for DM1 subjects. SPECT showed minimal hypoperfusion in the posterior cortex planes in DM1 and, to a lesser extent, in DM2. Very mild degrees of involvement in the DM2 cohort were seen. Neuroimaging and functional investigations confirmed a more severe involvement of the brain in DM1 compared to DM2. A temporo-insular diffuse lesional pattern, specific for DM1, was found on MRI. This confirms greater expansion size as a risk factor for more extensive brain involvement in DM1.     

Endoscopic characteristics and levodopa responsiveness of swallowing function in progressive supranuclear palsy

Dysphagia is a frequent and early symptom in progressive supranuclear palsy (PSP) predisposing patients to aspiration pneumonia. Fiberoptic endoscopic evaluation of swallowing (FEES®) has emerged as a valuable apparative tool for objective evaluation of neurogenic dysphagia. This is the first study using FEES® to investigate the nature of swallowing impairment in PSP. Eighteen consecutive PSP patients (mean age 69.7 ± 9.0 years) were included. The salient findings of FEES® in PSP patients were compared with those of 15 patients with Parkinson's disease (PD). In 7 PSP patients, a standardized FEES® protocol was performed to explore levodopa (L ‐dopa) responsiveness of dysphagia. Most frequent abnormalities detected by FEES® were bolus leakage, delayed swallowing reflex, and residues in valleculae and piriformes. Aspiration events with at least one food consistency occurred in nearly 30% of PSP patients. Significant pharyngeal saliva pooling was observed in 4 PSP patients. We found no difference of salient endoscopic findings between PSP and PD patients. Endoscopic dysphagia severity in PSP correlated positively with disease duration, clinical disability, and cognitive impairment. No correlation was found with dysarthria severity. In early PSP patients, swallowing dysfunction was solely characterized by liquid leakage with the risk of predeglutitive aspiration during the oral phase of swallowing. Two PSP patients showed relevant improvement of swallowing function after L ‐dopa challenge. Chin tuck—maneuver, hard swallow, and modification of food consistency were identified as the most effective therapeutic interventions. In conclusion, FEES® assessment can deliver important findings for the diagnosis and refined therapy of dysphagia in PSP patients. © 2010 Movement Disorder Society     

Dysphagia in myasthenia gravis: the tip of the Iceberg

We evaluated swallowing function in patients with myasthenia gravis (MG) with or without dysphagia symptoms using different evaluation parameters and compared the results with those of healthy subjects. A total of 36 patients with MG and 25 healthy volunteers were included in the study. The subjects were classified into three groups; patients without dysphagia (group 1), patients with dysphagia (group 2), and healthy participants (group 3). The presence and severity of dysphagia, the oropharyngeal, pharyngeal, pharyngoesophageal, and esophageal phases were assessed using a screening test, manometric test, electrophysiologic studies [electroneuromyography (EMG)], fiberoptic endoscopic evaluation of swallowing (FEES), and barium swallow pharyngeal esophagography (BSPE), respectively. There was a significant difference between group 1 and group 3 in terms of BSPE (p = 0.001) and manometry tests (p = 0.001). A significant difference was found in all methods between group 2 and group 3 (p = 0.001, for all). In the comparison of the patient groups, although the number of patients with dysphagia in group 2 was significantly higher in the clinical tests (p = 0.007), FEES (p = 0.001), and EMG (p = 0.043) than in group 1, no difference was detected for BSPE (p = 0.119) and manometry (p = 0.644). Swallowing functions in patients with MG may be affected even without symptoms. This condition should be considered in their follow-up.     

Spectral domain optical coherence tomography findings in myotonic dystrophy

The purpose of the study is to evaluate retinal involvement in a cohort of patients affected by Myotonic Dystrophy type 1 (DM1). Both eyes of 30 patients and one eye of a 31st patient with genetically proven diagnosis of DM1 and both eyes of 20 healthy age- and gender-matched subjects were enrolled. All patients underwent complete ophthalmologic examination including best-corrected visual acuity, intraocular pressure measurement, fundoscopy, fundus autofluorescence, infrared imaging and spectral-domain optical coherence tomography with central macular thickness measurement. DM1 patients showed statistically significant higher central macular thickness values than controls. In the DM1 group, butterfly (14.8%) and reticular (13.1%) pigment abnormalities were found with corresponding drusenoid deposit and focal disruption of photoreceptor and retinal pigment epithelium layers. Compared with the controls, DM1 group had higher prevalence of epiretinal membrane. In the DM1 group, the prevalence of epiretinal membrane and retinal pigment epithelium alterations were directly correlated with age, whereas no correlation was found with disease duration, CTG expansion and MIRS score. In conclusion, in addition to the typical retinal pigment epithelium changes, DM1 is also associated with abnormalities of the vitreoretinal interface, particularly epiretinal membrane, resulting in central macular thickness increase. Both inner and outer retinal alterations were associated with increasing age, suggesting that DM1 may cause a premature aging of the retina.     

Radiological evidence of subclinical dysphagia in motor neuron disease

Dysphagia in motor neuron disease (MND) may lead to dangerous complications such as cachexia and aspiration pneumonia. Functional evaluation of the oropharyngeal tract is crucial for identifying specific swallowing dysfunctions and planning appropriate rehabilitation. As part of a multidisciplinary study on the treatment of dysphagia in patients with neuromuscular diseases, 23 MND patients with different degrees of dysphagia underwent videoflouroscopy, videopharyngolaryngoscopy and pharyngo-oesophageal manometry. The results of the three instrumental investigations were analysed in order (1) to define the pattern of swallowing in MND patients complaining of dysphagia; (2) to evaluate whether subclinical abnormalities may be detected; and (3) to assess the role of videofluoroscopy, videopharyngolaryngoscopy and manometry in the evaluation of MND patients with deglutition problems. Correlations between the instrumental findings and clinical features (age of the patients, duration and severity of the disease, presence and degree of dysphagia) were also assessed. The results of our study showed that: (1) The oral phase of deglutition was compromised most often, followed by the pharyngeal phase. (2) In all patients without clinical evidence of dysphagia, subclinical videofluoroscopic alterations were present in a pattern similar to that found in the dysphagic group. (3) Videofluoroscopy was the most sensitive technique in identifying oropharyngeal alterations of swallowing. Impairment of the oral phase, abnormal pharyngo-oesophageal motility and incomplete relaxation of the upper oesophageal sphincter were the changes most sensitive in detecting dysphagia. Videofluoroscopy was also capable of detecting preclinical abnormalities in non-dysphagic patients who later developed dysphagia. Practical guidelines for the use of instrumental investigations in the assessment and management of dysphagia in MND patients are proposed. Received: 24 March 1997 Received in revised form: 11 November 1997 Accepted: 18 November 1997     

Dysphagia and multiple sclerosis

Over 30% of persons with multiple sclerosis (pwMS) suffer from swallowing symptoms, a higher rate than previously assumed. Neurogenic dysphagia (ND) may cause many different kinds of oropharyngeal sensorimotor dysfunctions in pwMS, and is associated with both the amount of disability and brainstem signs. About 15% of pwMS with mild disability may also suffer from ND. Diagnostic tools comprise history taking, bedside screening examination (50 ml water test combined with assessment of pharyngeal sensation or with pulse oximetry) and sometimes a videofluoroscopic swallowing study (VFSS) and fibreoptic endoscopic evaluation of swallowing (FEES). VFSS and FEES are complementary methods and both have advantages and disadvantages. Interventions for ND in pwMS are mainly based on functional swallowing therapy, including methods of restitution, compensation and adaptation. The aim of intervention is to prevent aspiration and aspiration pneumonia. Outcome assessment should focus on clinically relevant parameters, such as activity limitation, participation restriction and health-related quality of life.     

Validation of a swallowing disturbance questionnaire for detecting dysphagia in patients with Parkinson's disease.

Underreporting of swallowing disturbances by Parkinson's disease (PD) patients may lead to delay in diagnosis and treatment, alerting the physician to an existing dysphagia only after the first episode of aspiration pneumonia. We developed and validated a swallowing disturbance questionnaire (SDQ) for PD patients and compared its findings to an objective assessment. Fifty-seven PD patients (mean age 69 +/- 10 years) participated in this study. Each patient was queried about experiencing swallowing disturbances and asked to complete a self-reported 15-item "yes/no" questionnaire on swallowing disturbances (24 replied "no"). All study patients underwent a physical/clinical swallowing evaluation by a speech pathologist and an otolaryngologist. The 33 patients who complained of swallowing disturbances also underwent fiberoptic endoscopyic evaluation of swallowing (FEES). According to the ROC test, the "optimal" score (where the sensitivity and specificity curves cross) is 11 (sensitivity 80.5%, specificity 81.3%). Using the SDQ questionnaire substantially reduced Type I errors (specifically, an existing swallowing problem missed by the selected cutoff point). On the basis of the SDQ assessment alone, 12 of the 24 (50%) noncomplaining patients would have been referred to further evaluation that they otherwise would not have undergone. The SDQ emerged as a validated tool to detect early dysphagia in PD patients.     

Anxiety,depression and swallowing disorders in patients with Parkinson's disease

Swallowing disturbances (SDs), anxiety and depression are commonly present in Parkinson's disease (PD) patients. We hypothesized that there is an association between the presence of SDs and the PD affective state. Sixty-nine PD patients were assessed for the presence of SDs by undergoing cognitive screening with the Mini Mental State Examination (MMSE), completing three inventories: a swallowing disturbance questionnaire (SDQ), the Spielberger manual for the trait anxiety and Beck depression inventories. All patients underwent clinical swallowing evaluations by a speech and language pathologist (SLP). Patients diagnosed with SDs were also assessed by fiberoptic endoscopic evaluation of swallowing (FEES) performed by an ENT and SLP. Thirty-eight patients experienced SDs, the other 31 did not. The clinical characteristics of the two groups were matched. Patients with SDs experienced increased anxiety and depression compared to patients without SDs. Comparisons between patients who scored in the two opposite ends of the anxiety and depression ranges demonstrated that the most anxious and depressed patients reported more swallowing difficulties (SDQ scores) compared with the least anxious and depressed ones. In addition, the most anxious patients had significantly increased disease severity and decreased MMSE scores compared with the least anxious patients. Disease severity was also increased in the most depressed patients compared with the least depressed ones. Advanced disease emerged as being associated with high anxiety levels and greater numbers of SDs. The contribution of anxiety or depression to the development or worsening of SDs and their role in treatment strategy warrant further investigation.     

Functional impairment in patients with myotonic dystrophy type 1 can be assessed by an ataxia rating scale (SARA)

Myotonic dystrophy type 1 (DM1) is not characterised by ataxia per se; however, DM1 and ataxia patients show similar disturbances in movement coordination often experiencing walking and balance difficulties, although caused by different underlying pathologies. This study aims to investigate the use of a scale previously described for the assessment and rating of ataxia (SARA) with the hypothesis that it could have utility in DM1 patients as a measure of disease severity and risk of falling. Data from 54 DM1 patients were pulled from the PHENO-DM1 natural history study for analysis. Mean SARA score in the DM1 population was 5.45 relative to the maximum score of eight. A flooring effect (score 0) was observed in mild cases within the sample. Inter-rater and test–retest reliability was high with intraclass coefficients (ICC) of 0.983 and 1.00, respectively. Internal consistency was acceptable as indicated by a Cronbach’s alpha of 0.761. Component analysis revealed two principle components. SARA correlated with: (1) all measures of muscle function tested, including quantitative muscle testing of ankle dorsiflexion (r = ?0.584*), the 6 min walk test (r = ?0.739*), 10 m walk test (r = 0.741*), and the nine hole peg test (r = 0.602*) and (2) measures of disease severity/burden, such as MIRS (r = 0.718*), MDHI (r = 0.483*), and DM1-Activ (r = ?0.749*) (*p < 0.001). The SARA score was predicted by an interaction between modal CTG repeat length and age at sampling (r = 0.678, p = 0.003). A score of eight or above predicted the use of a walking aid with a sensitivity of 100% and a specificity of 85.7%. We suggest that further research is warranted to ascertain whether SARA or components of SARA are useful outcome measures for clinical trials in DM1. As a tool, it can be used for gathering information about disease severity/burden and helping to identify patients in need of a walking aid, and can potentially be applied in both research and healthcare settings.     

Dysphagiemanagement beim akuten Schlaganfall

Background

The German expert recommendations on the management of dysphagia in patients after acute stroke suggest an algorithm for clinical and technical investigations to identify patients at risk for aspiration and thus reduce the rate of aspiration pneumonia. The effectiveness of this algorithm has, however, not yet been prospectively validated .

Methods

In this study 144 consecutive stroke patients were assessed by a full bedside swallowing assessment including the screening procedures of standardized swallowing assessment (SSA) and 2 out of 6. Flexible endoscopic evaluation of swallowing (FEES) was performed in all patients.

Results

Aspiration was diagnosed in 25 patients (17.4%) by FEES. The SSA predicted aspiration with a sensitivity of 76% and a specificity of 55.5% and the 2 out of 6 screening with a sensitivity of 68.0% and a specificity of 61.0%. Of the patients 7 with negative screening for 2 out of 6 and 6 patients with negative SSA showed silent aspiration with the penetration aspiration scale (PAS 8) during FEES (28% of all patients with aspiration). Significant predictors for aspiration were dysarthria, dysphonia, abnormal volitional cough and cough after swallowing water; however, in multivariable analysis only dysarthria and cough after swallowing water were identified as independent predictors for aspiration. The rate of aspiration pneumonia was 2.8%.

Conclusion

Clinical screening alone is not sufficient to identify patients at risk for aspiration pneumonia. The FEES should be used at a low threshold in cases of severe stroke and minor clinical abnormalities, especially concerning isolated dysarthria and cough after swallowing water; therefore, current recommendations should be correspondingly modified.

     

Task-dependent differences in corticobulbar excitability of the submental motor projections: Implications for neural control of swallowing

It has been suggested that the primary motor cortex plays a substantial role in the neural circuitry that controls swallowing. Although its role in the voluntary oral phase of swallowing is undisputed, its precise role in motor control of the more reflexive, pharyngeal phase of swallowing is unclear. The contribution of the primary motor cortex to the pharyngeal phase of swallowing was examined using transcranial magnetic stimulation (TMS) to evoke motor evoked potentials (MEPs) in the anterior hyomandibular muscle group during either volitional submental muscle contraction or contraction during the pharyngeal phase of both volitionally, and reflexively, initiated swallowing. For each subject, in all three conditions, TMS was triggered when submental surface EMG (sEMG) reached 75% of the mean maximal submental sEMG amplitude measured during 10 volitional swallows. MEPs recorded during volitional submental muscle contraction were elicited in 22 of the 35 healthy subjects examined (63%). Only 16 of these 22 subjects (45.7%) also displayed MEPs recorded during volitional swallowing, but their MEP amplitudes were larger when triggered by submental muscle contraction than when triggered by volitional swallowing. Additionally, only 7 subjects (of 19 tested) showed MEPs triggered by submental muscle contraction during a reflexively triggered pharyngeal swallow. These differences indicate differing levels of net M1 excitability during execution of the investigated tasks, possibly brought about by task-dependent changes in the balance of excitatory and inhibitory neural activity.     

Daytime somnolence in myotonic dystrophy

Somnolence in myotonic dystrophy (DM) has not been measured using a reliable daytime somnolence scale. The aim of this study was to compare somnolence in DM patients with healthy controls and Charcot-Marie-Tooth disease (CMT) patients using such a scale and to compare this with potential contributory factors. We investigated 35 subjects with adult-onset DM, 16 healthy controls and 13 CMT controls. The Epworth Sleepiness Scale (ESS) was the principal measurement of daytime somnolence. Nocturnal sleep was assessed using a sleep diary. Other assessments measured daytime respiratory function, cognitive function, motor impairment, disability, swallowing capacity and depression. DM and CMT patients had greater daytime sleepiness than unaffected controls. In the DM group significant correlations were found between somnolence and measures of disability, sleep quality and some measures of depression. It was concluded that there is an abnormal level of daytime somnolence in DM, which is partially associated with disability. Received: 2 March 1998 Received in revised form: 14 July 1998 Accepted: 4 August 1998     

The importance of the reproducibility of oropharyngeal swallowing in amyotrophic lateral sclerosis. An electrophysiological study

Objective

To investigate electrophysiologically the reproducibility of oropharyngeal swallowing in patients with ALS.

Characteristics of respiratory muscle involvement in myotonic dystrophy type 1

The pathophysiology of respiratory muscle weakness in myotonic dystrophy type 1 (DM1) remains incompletely understood. 21 adult patients with DM1 (11 men, 42 ± 13 years) and 21 healthy matched controls underwent spirometry, manometry, and diaphragm ultrasound. In addition, surface electromyography of the diaphragm and the obliquus abdominis muscle was performed following cortical and posterior cervical magnetic stimulation (CMS) of the phrenic nerves or magnetic stimulation of the lower thoracic nerve roots. Magnetic stimulation was combined with invasive recording of the twitch transdiaphragmatic and gastric pressure (twPdi and twPgas) in 10 subjects per group. The following parameters were reduced in DM1 patients compared to control subjects: maximum inspiratory pressure (MIP; 40.3 ± 19.2 vs. 95.8 ± 28.5 cmH₂O, p < 0.01), diaphragm thickening ratio (DTR; 2.0 ± 0.4 vs. 2.7 ± 0.6, p < 0.01), twPdi following CMS (10.8 ± 8.3 vs. 21.4 ± 10.1 cmH2O, p = 0.03), and amplitude of diaphragm compound muscle action potentials (0.10 ± 0.25 vs. 0.46 ± 0.35 mV; p = 0.04). MIP and DTR were significantly correlated with the muscular impairment rating scale (MIRS) score. Maximum expiratory pressure (MEP) was reduced in DM1 patients compared to controls (41.3 ± 13.4 vs. 133.8 ± 28.0 cmH2O, p < 0.01) and showed negative correlation with the MIRS score. Pgas following a maximum cough was markedly lower in patients than in controls (71.9 ± 43.2 vs. 102.4 ± 35.5 cmH₂O) but without statistical significance (p = 0.06). In DM1, respiratory muscle weakness relates to clinical disease severity and involves inspiratory and probably expiratory muscle strength. Axonal phrenic nerve pathology may contribute to diaphragm dysfunction.