Floppy epiglottis as a contraindication of CPAP in patients with multiple system atrophy

Sleep apnea patients with epiglottic collapse elevate their larynx more with swallowing; videofluoroscopic swallowing study of 80 patients

OBJECTIVE

The epiglottis plays an integral role in the swallowing mechanism and is also implicated as an obstruction site in obstructive sleep apnea (OSA). The underlying causes of epiglottic collapse during sleep remain unclear. This study aimed to investigate the cognitive functions using the Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) and the neurophysiological and anatomical factors using videofluoroscopic swallowing studies (VFSS). We compared patients with OSA exhibiting epiglottic collapse to those without, assessing differences in anatomical or neurophysiological characteristics.

METHODS

The study included 12 patients with epiglottic collapse (Epi-group) and 68 without (non-Epi group), all undergoing overnight polysomnography (PSG), drug-induced sleep endoscopy (DISE), LOTCA, and VFSS. Oral transit time (OTT), pharyngeal delay time (PDT), and pharyngeal transit time (PTT) were considered as neurophysiological traits, and laryngeal elevation length (LE) as anatomical trait, and were measured across various test diets (10 ml of liquid, soft, or solid).

RESULTS

The study comprised 80 individuals, 57 men and 23 women, with no significant age, sex, body mass index or PSG parameters between groups, or DISE findings, with the exception of epiglottic collapse. Swallowing metrics from VFSS were normal, with no differences in OTT, PDT, PTT, or LOTCA scores. Notably, patients with epiglottic collapse showed a greater laryngeal elevation when swallowing soft and solid foods (p = 0.025 and p = 0.048, respectively).

CONCLUSIONS

Patients with epiglottic collapse do not exhibit neurophysiological or cognitive impairments when compared to non-Epi group. However, the Epi-group displayed a significantly increased laryngeal elevation length. This suggests that anatomical factors may have a more substantial role in the development of epiglottic collapse than neurophysiological factors.

Variation of respiratory and pulse events in multiple system atrophy

INTRODUCTION

A study is eagerly awaited that will reveal the unknown mechanisms of multiple system atrophy (MSA), in which the risk of sudden death is the greatest during sleep. The blunted pulse response to nocturnal respiratory events suggests an abnormal cardiac response to a sleep-related breathing disorder. Patients with MSA have a lower pulse event index (PEI), despite a greater hypoxic burden and a similar frequency of respiratory events. However, the evidence is speculative and not directly proven, and many limitations require further study.

METHODS

We conducted a retrospective analysis of 26 patients with MSA who had undergone overnight oximetry between April 2016 and December 2022.

RESULTS

The median 4% oxyhemoglobin desaturation index (ODI) was 11.6/h, the 6-bpm PEI was 8.9/h, and the PEI/ODI ratio was as low as 0.91. There were three patients with suspected sudden death; all had low PEI/ODI ratios. The PEI/ODI ratio was followed over time in seven patients, all of whom had a decrease in the ratio. However, the PEI was higher than the ODI in 12/26 (46%) of the patients.

CONCLUSION

A low PEI/ODI ratio, reflecting a blunted pulse response to nocturnal respiratory events in patients with MSA, may indicate a worse prognosis. This finding and the significance of the longitudinal decrease in the PEI/ODI ratio will require a prospective study.

The effect of CPAP on the upper airway and ventilatory flow in patients with obstructive sleep apnea

BACKGROUND

Continuous positive airway pressure (CPAP) is the mainstay of treatment for obstructive sleep apnea (OSA). However, data about its effect on the upper airway, especially the epiglottis, are scarce. The aim of this study was to investigate the changes in upper airway dimensions and inspiratory flow in response to incremental pressure levels.

METHODS

This is a secondary analysis of a prospective clinical trial in which patients with moderate to severe OSA underwent drug-induced sleep endoscopy with simultaneous recordings of flow and mask pressure. CPAP was titrated in small increments. For each pressure level a representative 3-breath segment was selected to determine specific flow features. The corresponding endoscopic footage was reviewed to assess the degree of upper airway collapse in a semi-quantitative manner.

RESULTS

A total of 214 breath segments were obtained from 13 participants (median [Q1-Q3]; apnea-hypopnea index, 24.9 [20.1-43.9] events/h; body mass index 28.1 [25.1-31.7] kg/m²). CPAP significantly increased cross-sectional dimensions of the soft palate, lateral walls and tongue base, but not of the epiglottis, and induced epiglottis collapse in one subject. Increased pressure improved peak inspiratory flow and median ventilation in all patients, even in the presence of persistent epiglottis collapse.

CONCLUSION

CPAP does not effectively address epiglottis collapse in patients with OSA. However, it normalizes inspiratory flow regardless of its effect on the epiglottis. This clinical trial was registered on January 18th, 2020 on ClinicalTrials.gov with identifier NCT04232410.

Optimizing Aerodynamic Vocal Parameters by Varying Supraglottic Pressure Using "Controlled Supraglottic Pressure Phonation" in Healthy Subjects

OBJECTIVE

The objective of this study is to introduce a novel method for semi-occluded vocal tract (SOVT) therapy called "controlled supraglottic pressure phonation," determine the mechanism by which supraglottic pressure contributes to lowering impedance during SOVT therapy, and provide the optimal supraglottic pressure range for SOVT exercises.

METHODS

Twenty-five human subjects were assigned to one of five supraglottic pressure levels, 0, 2, 4, 6, and 8 cmH2O, which were controlled through a continuous positive airway pressure device. Subjects were asked to phonate during both a short- and long-duration task, in which vocal properties were measured before and after. At the end of each task, the subjects reported the levels of discomfort and phonation difficulty on a 0-10 scale to assess the subjective improvement of vocal economy.

RESULTS

Significant differences were observed between pre- and post-task measurements for phonation threshold pressure for both the short-duration and long-duration tasks. Phonation threshold flow and frequency measurements were found to have no statistically significant differences. The subjective measures showed elevated discomfort in the higher pressure inputs for both tasks relative to no air.

CONCLUSION

Higher supraglottic pressure levels will improve ease of phonation, but the treatment discomfort needs to be considered as well, yielding an optimal supraglottic pressure range of 4-6 cmH2O. "Controlled supraglottic pressure phonation" serves as an alternative to straw phonation that may produce additional benefits.

Oral appliance therapy for obstructive sleep apnea in multiple system atrophy with floppy epiglottis: a case series of three patients

PURPOSE

A recent study demonstrated that continuous positive airway pressure (CPAP) may exacerbate obstructive sleep apnea (OSA) in patients with multiple system atrophy (MSA) and a floppy epiglottis (FE) as the CPAP promotes downward displacement of the epiglottis into the laryngeal inlet. In this case series, we examined the effectiveness of an oral appliance (OA) for treating OSA in three patients with MSA and an FE.

METHODS

Patients with MSA were demonstrated to have an FE on fiberoptic laryngoscopy under sedation using intravenous propofol. The therapeutic intervention was fitting an OA. Polysomnography (PSG) was performed subsequently with the OA in place.

RESULTS

In three patients with MSA, some parameters used to assess the severity of OSA improved with an OA. Both apnea-hypopnea index (AHI) and arousal index (ArI) decreased while wearing the OA in two cases while in the third case, apnea index (AI) and cumulative time at peripheral oxygen saturation (SpO₂) below 90% (CT90) decreased, but AHI and ArI increased. The only side effects were transient TMJ discomfort, masseter muscle pain, and tooth discomfort.

CONCLUSION

OA therapy using a two-piece type mandibular advancement device (MAD) may be a useful treatment intervention for patients with OSA who have MSA and FE.

Nocturnal Pulse Event Frequency Is Reduced in Multiple System Atrophy

Risk of sudden death in multiple system atrophy (MSA) is greatest during sleep with unknown mechanisms. We compared nocturnal pulse event frequency in 46 MSA patients and age-/sex-matched controls undergoing overnight pulse oximetry. Nocturnal oxyhemoglobin desaturation indices and pulse event indices (PEIs) were recorded, and relationships between pulse oximetry variables and survival were analyzed. MSA patients had lower PEI (3.1 ± 5.3 vs. 12.8 ± 10.8, p < 0.001) despite greater hypoxic burden and similar frequency of respiratory events. Nocturnal pulse events were not associated with severity of daytime autonomic failure. Two MSA patients had suspected sudden death, both with severely reduced PEI. MSA patients have fewer nocturnal pulse events compared with controls, despite similar respiratory event frequency, suggesting abnormal cardiac responses to sleep-disordered breathing. Whether this contributes to sudden death in MSA requires further study. ANN NEUROL 2023;93:205-212.

The clinical application progress and potential of drug-induced sleep endoscopy in obstructive sleep apnea

Background and Objective: Obstructive sleep apnoea (OSA) is characterized by nocturnal repetitive upper airway (UA) collapse. For sleep physicians, the recognition of UA collapse characteristics is critical for understanding OSA mechanisms and developing individualized treatment plans. Drug-induced sleep endoscopy (DISE) is an exam during simulated sleep that allows the dynamic assessment of the UA of individuals with OSA. The initial recognition of DISE was to locate the sites of UA obstruction and direct the surgical selection of OSA since it was introduced in the 1990s. After approximately 30 years of studies, based on advances in endoscopic operative techniques and innovative treatments of OSA, DISE had been performed to explore mechanisms and comprehensive treatments related to UA collapse. Methods: This article reviewed contemporary DISE advances, including indications and contraindications, technique of induced sleep, endoscopic operation, UA characteristics classification.Results and Conclusions: Precise selection based on the association between collapse patterns and treatment modalities, such as continuous positive airway pressure, oral appliance, positional therapy, robotic surgery and neurostimulator implanting, is the future research prospect based on DISE.Key messagesDISE provides sleep physicians with valuable information about the upper airway collapse characteristics and dynamic changes during sleep.The studies based on DISE findings improve the selectivity and efficiency of treatment modalities, including classical therapies such as continuous positive airway pressure, oral appliance, positional therapy, and innovative therapies such as neurostimulator implanting and robotic surgery, promote the advancement of OSA precision medicine.

Patients with Epiglottic Collapse Are Less Adherent to Autotitrating Positive Airway Pressure Therapy for Obstructive Sleep Apnea

Rationale: The anatomic orientation of the epiglottis is such that it points in the opposite direction to inspiratory flow, thereby potentially making positive airway pressure (PAP) treatment challenging in patients with epiglottic collapse. However, no previous studies have analyzed PAP adherence in these patients. Objectives: This study aimed to analyze adherence to autotitrating PAP (APAP) treatment in patients with epiglottic collapse. Methods: We performed an age- and sex-matched case-control study. On the basis of their overnight level-I polysomnogram, patients were prescribed APAP in a tertiary hospital between July 2018 and March 2019. The site of airway collapse was diagnosed with drug-induced sleep endoscopy. Demographic factors, sleep questionnaire, polysomnography, and APAP usage statistics were analyzed. Results: Eighteen patients with epiglottic collapse (epi-group) and 36 without epiglottic collapse (control group) were analyzed. We found that 22.8% of patients in the epi-group terminated APAP within 2 weeks, whereas only 2.8% of patients in the control group terminated APAP within 2 weeks (P = 0.048). The percentage of days with usage over 4 hours was significantly lower in the epi-group (64.6% vs. 75.6%; P = 0.008). In addition, the adherence failure rate was 66.7% in the epi-group and 33.3% in the control group (P = 0.039). Patients with epiglottic collapse were also found to have lower body mass index, which is an unfavorable predictor of APAP adherence. Conclusions: This study suggests that patients with epiglottic collapse have a higher APAP adherence failure rate than patients without epiglottic collapse. Thus, patients with epiglottic collapse should be followed closely during treatment, and alternative therapies should probably be considered for these patients.

Can drug-induced sleep endoscopy (DISE) predict compliance with positive airway pressure therapy? A pilot study

PURPOSE

Drug-induced sleep endoscopy (DISE) has been poorly explored as an examination to assess positive airway pressure (PAP) therapy in patients with obstructive sleep apnea (OSA). The present study aimed to identify by DISE possible characteristics related to low compliance with PAP therapy due to respiratory complaints.

METHODS

Patients using PAP for OSA underwent DISE in two conditions: (1) baseline (without PAP) and (2) PAP (with the same mask and airway pressure used at home). We compared patients reporting low compliance to PAP due to respiratory complaints to those well-adapted to therapy. VOTE classification (assessment of velopharynx, oropharynx, tongue base, and epiglottis) and TOTAL VOTE score (the sum of VOTE scores at each anatomical site) were assessed. ROC curve analyzed the accuracy of TOTAL VOTE to predict low compliance due to persistent pharyngeal obstruction in both conditions.

RESULTS

Of 19 patients enrolled, all presented multilevel pharyngeal obstruction at baseline condition, with no difference between groups at this study point. When PAP was added, the median VOTE value was higher in the epiglottis (P value=0.02) and tended to be higher at the velum and tongue base in the poorly adapted group; TOTAL VOTE score was also significantly increased in patients with low compliance (P value<0.001). ROC curve demonstrated that patients with TOTAL VOTE scored 2.5 or more during DISE with PAP presented a 4.6-fold higher risk for low compliance with PAP therapy due to pharyngeal obstruction (AUC: 0.88±0.07; P value<0.01; sensitivity: 77%; specificity: 83%).

CONCLUSIONS

Adding PAP during a DISE examination may help to predict persistent pharyngeal obstruction during PAP therapy.

Evaluation of the relationship between airway measurements with ultrasonography and laryngoscopy in newborns and infants

BACKGROUND

A difficult laryngoscopy in young children can be a stressful situation for the pediatric anesthetist. In recent years, several measurements have been used to obtain difficult laryngoscopy markers in children. However, there is no prospective study in which ultrasonography is expected to be used for this purpose, particularly in the newborn and infant age groups.

GOALS

In this study, our goal was to evaluate the relationship between the preoperative airway assessment tools and the difficult laryngoscopic view in neonates and infants.

METHODS

Our study included newborns and infants undergoing elective surgery requiring intubation under general anesthesia. The following measurements were recorded the following: patients' age, body mass index, thyromental distance, mandibular length, the distance between the lip corner and ipsilateral ear tragus, and the transverse length (measured by hand with sign-middle-ring fingers side by side). In the thyromental distance measurement, the "thyroid notch" was determined by ultrasonography. Glottic structures appearing during laryngoscopy were graded according to the Cormack-Lehane Classification.

RESULTS

Of the 150 patients included in the study, 36 were female, and 92% were under the age of one. The incidence of difficult laryngoscopic views was 8% in the age groups studied, and the frequency of difficult laryngoscopic views in the newborn age group was 14.3%. The relationship between airway assessment tools and the Cormack-Lehane Classification scores was statistically significant. The negative predictive value was high for all values.

CONCLUSIONS

The risk of a difficult laryngoscopy increases in children under the age of one. The preoperative airway assessment tools and body mass index had acceptable negative predictive values. We believe that all measurements could be used as markers for difficult laryngoscopy in newborns and infants.

Stridor during sleep: description of 81 consecutive cases diagnosed in a tertiary sleep disorders center

Study Objectives

To describe the characteristics of stridor during sleep (SDS) in a series of adults identified by video-polysomnography (V-PSG).

Methods

Retrospective clinical, V-PSG, laryngoscopic, and therapeutic data of patients diagnosed with SDS in a tertiary referral sleep disorders center between 1997 and 2017.

Results

A total of 81 patients were identified (56.8% males, age 61.8 ± 11.2 years). Related etiologies were multiple system atrophy (MSA), amyotrophic lateral sclerosis, spinocerebellar ataxia type 1, anti-IgLON5 disease, fatal familial insomnia, brainstem structural lesions, vagus nerve stimulation, recurrent laryngeal nerve injury, the effect of radiotherapy on the vocal cords, cervical osteophytes, and others. Stridor during wakefulness coexisted in 13 (16%) patients and in MSA was only seen in the parkinsonian form. Laryngoscopy during wakefulness in 72 (88.9%) subjects documented vocal cord abductor impairment in 65 (90.3%) and extrinsic lesions narrowing the glottis in 2 (2.4%). The mean apnea–hypopnea index (AHI) was 21.4 ± 18.6 and CT90 was 11.5 ± 19.1. Obstructive AHI &gt; 10 occurred in 52 (64.2%) patients and central apnea index &gt;10 in 2 (2.4%). CPAP abolished SDS, obstructive apneic events and oxyhemoglobin desaturations in 58 of 60 (96.7%) titrated patients with optimal pressure of 9.0 ± 2.3 cm H20. Tracheostomy in 19 (23.4%) and cordotomy in 3 (3.7%) subjects also eliminated SDS.

Conclusions

SDS in adults is linked to conditions that damage the brainstem, recurrent laryngeal nerve, and vocal cords. V-PSG frequently detects obstructive sleep apnea and laryngoscopy usually shows vocal cord abductor dysfunction. CPAP, tracheostomy, and laryngeal surgery abolish SDS.

Laryngeal Movement Disorders in Multiple System Atrophy: A Diagnostic Biomarker?

Background

Multiple system atrophy (MSA) is a rare neurodegenerative disorder, and its parkinsonian variant can be difficult to delineate from Parkinson's disease (PD). Despite laryngeal dysfunction being associated with decreased life expectancy and quality of life, systematic assessments of laryngeal dysfunction in large cohorts are missing.

Objectives

The objective of this study was to systematically assess laryngeal dysfunction in MSA and PD and identify laryngeal symptoms that allow for differentiating MSA from PD.

Methods

Patients with probable or possible MSA underwent flexible endoscopic evaluation of swallowing performing a systematic task protocol. Findings were compared with an age‐matched PD cohort.

Results

A total of 57 patients with MSA (64 [59–71] years; 35 women) were included, and task assessments during endoscopic examination compared with 57 patients with PD (67 [60–73]; 28 women). Patients with MSA had a shorter disease duration (4 [3–5] years vs 7 [5–10]; P < 0.0001) and higher disease severity (Hoehn & Yahr stage 4 [3–4] vs 3 [2–4]; P < 0.0001). Of the patients with MSA, 43.9% showed clinically overt laryngeal dysfunction with inspiratory stridor. During endoscopic task assessment, however, 93% of patients with MSA demonstrated laryngeal dysfunction in contrast with only 1.8% of patients with PD (P < 0.0001). Irregular arytenoid cartilages movements were present in 91.2% of patients with MSA, but in no patients with PD (P < 0.0001). Further findings included vocal fold motion impairment (75.4%), paradoxical vocal fold motion (33.3%), and vocal fold fixation (19.3%). One patient with PD showed vocal fold motion impairment.

Conclusion

Laryngeal movement disorders are highly prevalent in patients with MSA when assessed by a specific task protocol despite the lack of overt clinical symptoms. Our data suggest that irregular arytenoid cartilage movements could be used as a clinical marker to delineate MSA from PD with a specificity of 1.0 and sensitivity 0.9. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Airway Obstruction Caused by Mucinous Material Adherent to the Epiglottis in a Patient with a Progressive Neurological Disorder: An Unusual Case of a Condition Mimicking Acquired Laryngomalacia

We herein report the successful management of a condition mimicking acquired laryngomalacia using conservative methods in an elderly man with a progressive neurological disorder. The patient developed stridor and was transferred to the intensive-care unit. Flexible laryngoscopy revealed a collapsed epiglottis during inspiration, as seen in acquired laryngomalacia, with mucinous material firmly adhered to the epiglottis. The stridor resolved after the removal of this material. Pathology revealed keratinized material, suggesting a collection of sputum or epithelial tissue. Thus, flexible laryngoscopy can differentiate the cause of airway obstruction and avoid unnecessary endotracheal intubation in patients with neurological disorders.

Critical appraisal of clinical trials in multiple system atrophy: Toward better quality

Multiple system atrophy (MSA) is a rare neurodegenerative disease of undetermined cause. Although many clinical trials have been conducted, there is still no treatment that cures the disease or slows its progression. We sought to assess the clinical trials, methodology, and quality of reporting of clinical trails conducted in MSA patients. We conducted a systematic review of all trials with at least 1 MSA patient subject to any pharmacological/nonpharmacological interventions. Two independent reviewers evaluated the methodological characteristics and quality of reporting of trials. A total of 60 clinical trials were identified, including 1375 MSA patients. Of the trials, 51% (n = 31) were single-arm studies. A total of 28% (n = 17) had a parallel design, half of which (n = 13) were placebo controlled. Of the studies, 8 (13.3%) were conducted in a multicenter setting, 3 of which were responsible for 49.3% (n = 678) of the total included MSA patients. The description of primary outcomes was unclear in 60% (n = 40) of trials. Only 10 (16.7%) clinical trials clearly described the randomization process. Blinding of the participants, personnel, and outcome assessments were at high risk of bias in the majority of studies. The number of dropouts/withdrawals was high (n = 326, 23.4% among the included patients). Overall, the design and quality of reporting of the reviewed studies is unsatisfactory. The most frequent clinical trials were small and single centered. Inadequate reporting was related to the information on the randomization process, sequence generation, allocation concealment, blinding of participants, and sample size calculations. Although improved during the recent years, methodological quality and trial design need to be optimized to generate more informative results. © 2017 International Parkinson and Movement Disorder Society.

Management of sleep disorders in Parkinson's disease and multiple system atrophy

Parkinson's disease (PD) and multiple system atrophy (MSA) are disorders associated with α synuclein-related neurodegeneration. Nonmotor symptoms are common hallmarks of these disorders, and disturbances of the sleep-wake cycle are among the most common nonmotor symptoms. It is only recently that sleep disturbances have received the attention of the medical and research community. Significant progress has been made in understanding the pathophysiology of sleep and wake disruption in alphasynucleinopathies during the past few decades. Despite these advancements, treatment options are limited and frequently associated with problematic side effects. Further studies that center on the development of novel treatment approaches are very much needed. In this article, the author discusses the current state of the management of disturbed sleep and alertness in PD and MSA. © 2017 International Parkinson and Movement Disorder Society.

Mechanisms and prevention of sudden death in multiple system atrophy

BACKGROUND

Sudden death in multiple system atrophy (MSA) usually occurs during sleep and was therefore attributed to suffocation resulting from vocal cord abductor paralysis, a characteristic laryngeal finding of MSA. This led to the use of tracheostomy and noninvasive positive pressure ventilation (NPPV) for the prevention of sudden death. However, neither method has been able to prevent sudden death, and both have occasionally precipitated treatment-related complications, including central sleep apneas and exacerbation of floppy epiglottis. Therefore, it is important to determine the mechanisms and prevention of sudden death in MSA.

METHODS

We reviewed the literature on the mechanisms and prevention of sudden death in patients with MSA.

RESULTS

Sudden death in MSA is hypothesized to be a consequence of disordered central respiration, suffocation caused by sputum and food, upper airway obstruction from NPPV acting on a floppy epiglottis, cardiac autonomic disturbance, or a combination of these factors.

CONCLUSION

Various factors may be involved in the mechanism of sudden death in MSA. A multidisciplinary approach is needed to prevent sudden death, and this requires an organized system of several medical specialties. Neurologists require a cooperative network that includes experts in otorhinolaryngology, sleep medicine, dysphagia rehabilitation, and cardiology.

Use of a new generation of adaptive servo ventilation for sleep-disordered breathing in patients with multiple system atrophy

A 70-year-old man (case 1) and a 64-year-old woman (case 2) with multiple system atrophy (MSA) and snoring were admitted for polysomnography. Their awake PaCO2 indicated normocapnia. Apnoea-hypopnoea index (AHI), max transcutaneous carbon dioxide partial pressure (PtcCO2) and ΔPtcCO2 (max PtcCO2 (during sleep)-baseline PtcCO2 (while awake)) were 11.4/h, 63 mm Hg and 18 mm Hg, respectively, in case 1 and 53.1/h, 59 mm Hg and 13 mm Hg, respectively, in case 2. Their sleep-disordered breathing (SDB) was diagnosed as obstructive sleep apnoea with hypoventilation. We thought that variable expiratory positive airway pressure and pressure support ventilation (advanced-adaptive servo ventilation (ASV)) might be favourable for their SDB. Polysomnography after introducing advanced-ASV revealed that AHI, max PtcCO2 and ΔPtcCO2 were 0.2/h, 53 mm Hg and 5 mm Hg, respectively, in case 1 and 1.5/h, 56 mm Hg and 9 mm Hg, respectively, in case 2. Advanced-ASV for treating Cheyne-Stokes breathing may be helpful in SDB in patients with MSA.

[Sleep and autonomic function: sleep related breathing disorders in Parkinson's disease and related disorders]

In patients with multiple system atrophy (MSA), sleep related breathing disorders (SRBD), including obstructive and central sleep apnea, vocal cord abductor paralysis and dysrhythmic breathing pattern, are frequently observed. SRBD may have a considerable impact on variation of autonomic nervous activity during sleep. The previous studies correlated upper airway muscle dysfunction related parkinsonism with increased prevalence of SRBD in patients with Parkinson's disease (PD). However, recently, the clinical significance of SRBD and its impact on sleepiness and disease severity have been debated. In this review, we discuss sleep and autonomic function, especially, SRBD in PD and related disorders, including the previous studies from our department.

Daytime sleepiness in Japanese patients with multiple system atrophy: prevalence and determinants

Background

The recent SLEEMSA study that evaluated excessive daytime sleepiness (EDS) in Caucasian patients with multiple system atrophy (MSA) demonstrated that EDS was more frequent in patients (28%) than in healthy subjects (2%). However, the prevalence and determinants of EDS in other ethnic populations have not been reported to date.

Methods

We performed a single-hospital prospective study on patients with probable MSA. To ascertain the prevalence and determinants of EDS in Japanese MSA patients, we assessed the patients’ degree of daytime sleepiness by using the Japanese version of the Epworth Sleepiness Scale (ESS). In addition, we investigated the effects of sleep-disordered breathing (SDB) and abnormal periodic leg movements in sleep (PLMS), which were measured by polysomnography, on the patients’ ESS scores.

Results

A total of 25 patients with probable MSA (21 patients with cerebellar MSA and 4 patients with parkinsonian MSA) were included in this study. All patients underwent standard polysomnography. The mean ESS score was 6.2 ± 0.9, and EDS was identified in 24% of the patients. SDB and abnormal PLMS were identified in 24 (96%) and 11 (44%) patients, respectively. The prevalences of EDS in patients with SDB and abnormal PLMS were 25% and 18%, respectively. No correlations were observed between ESS scores and the parameters of SDB or abnormal PLMS.

Conclusions

The frequency of EDS in Japanese patients with MSA was similar to that in Caucasian MSA patients. SDB and abnormal PLMS were frequently observed in MSA patients, although the severities of these factors were not correlated with EDS. Further investigations using objective sleep tests need to be performed.

[A case of amyotrophic lateral sclerosis with bilateral vocal cord paralysis necessitating tracheotomy]

Vocal cord movement disorders are increasingly recognized in patients with amyotrophic lateral sclerosis (ALS). We describe a patient with limb-onset ALS who developed vocal cord paralysis. A 74-year-old Japanese male consulted our clinic with a 6-month history of weakness in both arms. His family history was unremarkable. There were fasciculations and mild atrophy of the tongue and both arms. In the legs, muscle strength was almost normal but widespread fasciculations were present. All tendon reflexes were hypoactive and pathological reflexes were absent. Thereafter, he developed weakness of the legs and showed increased eating time. Babinski sign was positive bilaterally at this stage. The forced vital capacity dropped from 90% at the initial evaluation to 62% of the predicted value 14 months later. Two years after disease onset, the patient developed aspiration pneumonia with hoarseness and had difficulty clearing his throat of phlegm. Laryngoscopy demonstrated severe vocal cord paresis on both sides, particularly in the abductor muscles possibly leading to obstruction. Tracheotomy was performed because of the risk that the patient could choke to death. A review of the literature suggests that severe impairment of vocal cord abduction could be a prelude to sudden death in ALS. Follow up by laryngoscopic examination is necessary.