Laryngeal stridor in multiple system atrophy: Clinicopathological features and causal hypotheses

Vocal Fold Motion Impairment in Neurodegenerative Diseases

Vocal fold motion impairment (VFMI) is the inappropriate movement of the vocal folds during respiration, leading to vocal fold adduction and/or abduction problems and causing respiratory and vocal impairments. Neurodegenerative diseases (NDDs) are a wide range of disorders characterized by progressive loss of neurons and deposition of altered proteins in the brain and peripheral organs. VFMI may be unrecognized in patients with NDDs. VFMI in NDDs is caused by the following: laryngeal muscle weakness due to muscular atrophy, caused by brainstem and motor neuron degeneration in amyotrophic lateral sclerosis; hyperactivity of laryngeal adductors in Parkinson's disease; and varying degrees of laryngeal adductor hypertonia and abductor paralysis in multiple system atrophy. Management of VFMI depends on whether there is a presence of glottic insufficiency or insufficient glottic opening with/without severe dysphagia. VFMI treatment options for glottic insufficiency range from surgical interventions, including injection laryngoplasty and medialization thyroplasty, to behavioral therapies; for insufficient glottic opening, various options are available based on the severity and underlying cause of the condition, including continuous positive airway pressure therapy, botulinum toxin injection, tracheostomy, vocal fold surgery, or a combination of interventions. In this review, we outline the mechanisms, clinical features, and management of VFMI in NDDs and provide a guide for physicians who may encounter these clinical features in their patients. NDDs are always progressive; hence, timely evaluation, proper diagnosis, and appropriate management of the patient will greatly affect their vocal, respiratory, and swallowing functions as well as their quality of life.

Significance of clinical symptoms and red flags in early differential diagnosis of Parkinson's disease and atypical Parkinsonian syndromes

The clinical presentation of Parkinson's disease and atypical Parkinsonian syndromes is often heterogeneous. Additional diagnostic procedures including brain imaging and biomarker analyses can help to appreciate the various syndromes, but a precise clinical evaluation and differentiation is always necessary. To better assess the relevance of distinct clinical symptoms that arose within 1 year of disease manifestation and evaluate their indicative potential for an atypical Parkinsonian syndrome, we conducted a modified Delphi panel with seven movement disorder specialists. Five different topics with several clinical symptom items were discussed and consensus criteria were tested. This resulted in distinct symptom patterns for each atypical Parkinsonian syndrome showing the multitude of clinical involvement in each neurodegenerative disease. Strongly discriminating clinical signs were few and levels of indication were variable. A prospective validation of the assessments made is needed. This demonstrates that both clinical evaluation and elaborate additional diagnostic procedures are needed to achieve a high diagnostic standard.

Histopathological Features of Gerhardt Syndrome in a Patient With Multiple System Atrophy: An Autopsy Case Report

Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by autonomic failure, parkinsonism, and cerebellar ataxia. Gerhardt syndrome, which is inspiratory dyspnea with laryngeal stridor associated with dysfunction of the vocal folds, is a frequent and fatal complication of MSA. A 59-year-old man with a six-year history of MSA presented with ataxia and dysarthria. He also had dyspnea and stridor, which had worsened in the last three months, and died from respiratory distress. Autopsy revealed neurogenic group atrophy of the posterior cricoarytenoid (PCA) muscle, which suggested that laryngeal nerve damage caused abductor vocal fold paralysis in addition to cerebellar and brainstem atrophy with glial cytoplasmic inclusions. Our histopathological findings suggest that Gerhardt syndrome may be associated with neurogenic atrophy of the laryngeal abductor muscle (PCA muscle) of the vocal folds.

Sleep Dysfunction in Movement Disorders: a Window to the Disease Biology

PURPOSE OF REVIEW

To comprehensively summarize the sleep pathologies associated with movement disorders, focusing on neurodegenerative diseases.

RECENT FINDINGS

Mounting evidence has further implicated both sleep and circadian disruption in the pathophysiology of many movement disorders. In particular, recent data illuminate the mechanisms by which poor sleep quality and circadian dysfunction can exacerbate neurodegeneration. In addition, anti-IgLON5 disease is a recently described autoimmune disease with various symptoms that can feature prominent sleep disruption and parasomnia. Many movement disorders are associated with sleep and circadian rhythm disruption. Motor symptoms can cause sleep fragmentation, resulting in insomnia and excessive daytime sleepiness. Many neurodegenerative movement disorders involve brainstem pathology in regions close to or affecting nuclei that regulate sleep and wake. Further, commonly used movement medications may exacerbate sleep concerns. Providers should screen for and address these sleep symptoms to improve function and quality of life for patients and caregivers.

“Peculiar” Snoring in a 40-Year-Old Patient: A Case Report and Review of Literature

This is a case description of a patient with previously diagnosed rapid eye movement sleep behavior disorder (RBD) and nocturnal enuresis, who complained about a “peculiar sound” while sleeping and, occasionally, while awake during intensive exercise, for the last three months. A home audio recording, which his wife obtained while he was sleeping, showed a high-pitched sound identified as stridor. Full video polysomnography revealed no apneas or hypopneas. The flow-volume loop yielded an inspiratory plateau, indicating variable extrathoracic obstruction. The upper and lower respiratory system computed tomography did not show any anomalies or mechanical lesions (e.g., masses and scars). Fiberoptic laryngoscopy revealed an abnormal activity of the vocal cord abductor during quiet breathing and inspiration in a supine position, leading to partial obstruction. A positive dopamine transporter scan and the coexistence of stridor, RBD, and nocturnal enuresis were diagnostic for multiple system atrophy. The patient was treated with continuous positive airway pressure as a symptomatic therapy for stridor and levodopa.

Tracheostomy is associated with increased survival in multiple system atrophy patients with stridor

Background and purpose

Stridor treatment in multiple system atrophy (MSA) mainly comprises tracheostomy or continuous positive airway pressure (CPAP), but guidelines for the use of these treatments are lacking. The aim of the study was to evaluate the predictive value of stridor treatment in an MSA cohort.

Methods

This is a retrospective and prospective monocentric cohort study including MSA patients evaluated at least once a year during the disease course. Stridor was video‐polysomnography confirmed. The time of stridor treatment (CPAP or tracheostomy) and latency from stridor onset were collected. Survival and predictors of survival were calculated.

Results

A total of 182 (107 males, mean age at disease onset 57.3 ± 8.4 years) MSA patients were included in the study; 141 were deceased at the time of study. Of the total sample, 75 patients were diagnosed with stridor: 22 patients were treated with tracheostomy and 29 with CPAP, whilst 24 patients did not receive treatment. Treatment with tracheostomy showed longer survival compared with both treatment with CPAP or no treatment (incidence rate of death 12 vs. 21 vs. 23 per 100 person‐years, respectively). Tracheostomy remained an independent factor associated with longer survival (hazard ratio 0.38, p = 0.029), also after adjustment for other confounders and latency for stridor treatment.

Conclusions

This is the largest monocentric and long‐term follow‐up study comparing survival between tracheostomy and CPAP in MSA patients with stridor. Treatment with tracheostomy showed longer survival compared with both treatment with CPAP or no treatment. A careful multidisciplinary approach is required for the management of MSA patients with stridor.

Nocturnal stridor in multiple system atrophy: Video-polysomnography and clinical features

INTRODUCTION

Nocturnal stridor, a life-threatening condition linked to respiratory failure and sudden death during sleep, is a serious issue in patients with multiple system atrophy (MSA). However, little is known about polysomnographic findings and clinical features of MSA patients with nocturnal stridor. Hence, we investigated video-polysomnography (VPSG) findings and clinical features associated with nocturnal stridor in patients with MSA.

METHODS

We retrospectively analyzed the clinical data of patients with MSA (n = 49) who underwent overnight VPSG for the evaluation of sleep-disordered breathing. The presence of nocturnal stridor was confirmed based on overnight VPSG findings. Clinical data, including VPSG findings and clinical features, were compared between MSA patients with and without nocturnal stridor.

RESULTS

Nocturnal stridor was present in 31 (63.3%) patients with MSA. Patients with stridor showed significantly higher apnea-hypopnea, respiratory disturbance, and oxygen desaturation indices than those without stridor (P = 0.024, P = 0.049, and P = 0.006, respectively). Patients with stridor had more severe axial motor features, more impaired activities of daily living, and longer disease duration than those without stridor (P = 0.012, P = 0.036, and P = 0.003, respectively). However, there were no significant between-group differences in sex, age at disease onset, MSA subtype, parkinsonian features, cerebellar ataxia, residual urine volume, or systolic and diastolic blood pressure change.

CONCLUSIONS

MSA with nocturnal stridor is related to higher apnea indices in conjunction with higher O₂ desaturation index, more severe axial motor features, more impaired activities of daily living, and longer disease duration.

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 > 10 occurred in 52 (64.2%) patients and central apnea index >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.

Esophageal Dysmotility is Common in Patients With Multiple System Atrophy

OBJECTIVES

Esophageal dysmotility (ED) in patients with multiple system atrophy (MSA) are poorly understood. This study aimed to investigate the prevalence of ED in patients with MSA and to assess the relationship of esophageal abnormalities with other clinical findings and characteristics in these patients.

METHODS

A retrospective chart review was conducted to identify patients with MSA and to compare them to the elderly controls without MSA (65+ years) who underwent a videofluorographic esophagram from 2014 to 2019. Disease type, disease severity, vocal fold mobility impairment, abnormal deglutitive proximal esophageal contraction (ADPEC), and intra-esophageal stasis (IES) were reviewed and compared between groups.

RESULTS

Thirty-seven patients with MSA were identified. The median age was 63 and 26 (70%) were male. These patients were matched to 22 elderly adults with presbylarynx but not MSA (median age 77, 68% male). In MSA patients, cerebellar variant type was predominant (59%), and ADPEC was recognized in 18 patients (49%). Disease severity level (P = 0.028) and existence of IES (P = 0.046) were associated with higher risks of developing ADPEC. The prevalence of IES was significantly higher in patients with MSA (95%) compared to controls without MSA (46%) (P < 0.001). Disease severity level and the existence of IES were significantly associated with the presence of ADPEC (p < 0.05).

CONCLUSION

ADPEC and IES were significantly more common in MSA than in elderly subjects without MSA. MSA severity is associated with the development of ADPEC. The data suggest that esophageal motility is predominantly affected in MSA.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:832-838, 2021.

Sleep-Induced Glottis Closure in Multiple System Atrophy Evaluated by Four-Dimensional Computed Tomography

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder. Since patients with MSA often have sleep-related respiratory disorders including upper-airway obstruction and/or central sleep disturbance, appropriate evaluation of the upper airway especially during sleep may be indispensable. Fiberoptic laryngoscopy during diazepam-induced sleep has been reported for upper-airway obstruction verification. However, some patients cannot endure the uncomfortable sensation of the fiberscope. To address these issues, we devised a protocol of four four-dimensional computed tomography (4D-CT) for upper-airway evaluation during sleep. Here, we report the case of patient with MSA who was evaluated for upper-airway obstruction during sleep using 4D-CT. A 46-year-old man (height 1.60 m, weight 79 kg) was admitted to our neurological department for tracheal intubation because of a sudden onset of respiratory failure occurring at night. At the age of 45 years, he was diagnosed as MSA with predominant parkinsonism. As pulmonary disease had been excluded and his swallowing was normal, our differential diagnoses were central sleep apnea or obstructive sleep apnea related to his MSA or obstructive sleep apnea (SA) related to his obesity. A tracheostomy was done to maintain the airway after extubation. Polysomnography showed obstructive SA and not central SA. Awake fiberoptic laryngoscopy showed no upper airway obstruction but bilateral vocal abduction impairment (BVAI) during inspiration. To assess the spatial and temporal conditions of the upper respiratory tract—the patient could not tolerate sleep laryngoscopy—we carried out a 4D-CT. Reconstructed 4D-CT images of respiration during sleep showed clear abnormalities: glottis closure at the terminal stage of inspiration and subsequent velopharyngeal closure. As glottis closure does not occur normally in obesity patients, the cause of the respiratory failure in this patient was considered MSA-related sleep-induced airway obstruction. We decided to keep the tracheostoma, because BVAI in patients with MSA may be getting worse, although central apnea after tracheostomy may cause sudden central origin-related death; 4 months postoperatively, the patient had experienced no further airway-related complications. This report indicates that 4D-CT sequential upper-airway assessment during sleep is useful for determining the abnormalities causing obstructive SA in patients with MSA.

Various Motor and Non-Motor Symptoms in Early Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) patients pre-sent a variety of symptoms other than autonomic dysfunctions, parkinsonism, and cerebellar ataxia. The aim of this study was to evaluate the frequency of various motor and non-motor symptoms including so-called "red flags" in patients with early MSA and to determine whether the frequency of these symptoms was different between the parkinsonian (MSA-P) and cerebellar (MSA-C) subtypes.

METHODS

Sixty-one probable or possible MSA patients with disease duration of 3 years or less were included. Patients were classified into MSA-P, MSA-C, and MSA-PC. The frequency of 13 features including various motor and non-motor symptoms that commonly occur in MSA was assessed.

RESULTS

Dysarthria was the most prevalent feature (98.4%) followed by sexual dysfunction (95.1%). Probable REM sleep behavior disorder was present in 90.2%. The frequency of constipation (82.0%), dysphagia (68.9%), and snoring (70.5%) was also high. Stridor was present in 42.6% and more common in MSA-C than in MSA-P.

CONCLUSIONS

Increasing awareness of various motor and non-motor symptoms may assist clinicians to make an early, accurate diagnosis and to improve management of patients with MSA. We suggest that the diagnostic accuracy can be improved if these features are appropriately reflected in the new diagnostic criteria for MSA.

Emergency presentations of movement disorders

Movement disorders are typically perceived as being gradually progressive conditions that are managed in outpatient settings. However, they may manifest de novo with an acute severe phenotype or an acute decompensation. A movement disorder becomes an emergency when it evolves acutely or subacutely over hours to days; delays in its diagnosis and treatment may cause significant morbidity and mortality. Here we address the clinical presentation, diagnosis and management of those movement disorder emergencies that are principally encountered in emergency departments, in acute receiving units or in intensive care units. We provide practical guidance for management in the acute setting where there are several treatable causes not to be missed. The suggested medication doses are predominantly based on expert opinion due to limited higher-level evidence. In spite of the rarity of movement disorder emergencies, neurologists need to be familiar with the phenomenology, potential causes and treatments of these conditions. Movement disorder emergencies divide broadly into two groups: hypokinetic and hyperkinetic, categorised according to their phenomenology. Most acute presentations are hyperkinetic and some are mixed.

Stridor in multiple system atrophy: Consensus statement on diagnosis, prognosis, and treatment

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by a combination of autonomic failure, cerebellar ataxia, and parkinsonism. Laryngeal stridor is an additional feature for MSA diagnosis, showing a high diagnostic positive predictive value, and its early occurrence might contribute to shorten survival. A consensus definition of stridor in MSA is lacking, and disagreement persists about its diagnosis, prognosis, and treatment. An International Consensus Conference among experts with methodological support was convened in Bologna in 2017 to define stridor in MSA and to reach consensus statements for the diagnosis, prognosis, and treatment. Stridor was defined as a strained, high-pitched, harsh respiratory sound, mainly inspiratory, occurring only during sleep or during both sleep and wakefulness, and caused by laryngeal dysfunction leading to narrowing of the rima glottidis. According to the consensus, stridor may be recognized clinically by the physician if present at the time of examination, with the help of a witness, or by listening to an audio recording. Laryngoscopy is suggested to exclude mechanical lesions or functional vocal cord abnormalities related to different neurologic conditions. If the suspicion of stridor needs confirmation, drug-induced sleep endoscopy or video polysomnography may be useful. The impact of stridor on survival and quality of life remains uncertain. Continuous positive airway pressure and tracheostomy are both suggested as symptomatic treatment of stridor, but whether they improve survival is uncertain. Several research gaps emerged involving diagnosis, prognosis, and treatment. Unmet needs for research were identified.

Heightened risk of early vocal fold motion impairment onset and dysphagia in the parkinsonian variant of multiple system atrophy: a comparative study

Objective

We compared differences in frequency and timing of onset of the following clinical events between the cerebellar and parkinsonian variants of multiple system atrophy (MSA-C and MSA-P, respectively): type of operation including tracheostomy and/or aspiration prevention surgery, vocal fold motion impairment (VFMI), sleep apnea (SA), introduction of mechanical ventilation (MV), and dysphagia. The risks of these events cooccurring with either MSA-C or MSA-P were compared.

Methods

We retrospectively assessed clinical outcomes only of patients with MSA who presented at the Department of Otolaryngology of the University of Tokyo Hospital between 2008 and 2018. The proportion and timing of onset events between MSA-C and MSA-P and risks of onset were compared using chi-square tests and Cox proportional hazard models adjusted for age, sex, and disease severity, respectively.

Results

We identified 113 patients (median age: 60 years, 72 men [64%]). The frequency and timing of VFMI, SA, MV, dysphagia, and surgeries were 55 patients (49%) and 76 (95% CI 61–91) months after MSA onset, 85 (75%) and 41 (32–50), 36 (32%) and 100 (73–127), 77 (68%) and 43 (36–50), and 25 (22%) and 102 (84–120), respectively. Twenty-seven patients (24%) had MSA-P and higher risk of VFMI (p < .001), SA (p = .030), and dysphagia (p = .017) than did patients with MSA-C.

Conclusion

While MSA-P is less common, it may involve heightened risk of VFMI and dysphagia early onset. Thus, careful follow-up for VFMI, SA, and dysphagia may be needed for these patients.

Criteria for Rating Diagnostic Accuracy Studies

Class II.

•

The onset of vocal fold motion impairment varies in multiple system atrophy types

•

The sleep-apnea onset is relatively early in parkinsonian multiple system atrophy

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The onset of dysphagia is relatively early in parkinsonian multiple system atrophy

•

Respiratory clinical events are more common in parkinsonian multiple system atrophy

The Shaking Palsy of the Larynx-Potential Biomarker for Multiple System Atrophy: A Pilot Study and Literature Review

In its early stages multiple system atrophy (MSA), a neurodegenerative movement disorder, can be difficult to differentiate from idiopathic Parkinson's disease (PD), and emphasis has been put on identifying premotor symptoms to allow for its early identification. The occurrence of vegetative symptoms in addition to motor impairment, such as orthostatic hypotension and neurogenic bladder dysfunction, enable the clinical diagnosis in the advanced stages of the disease. Usually with further disease progression, laryngeal abnormalities become clinically evident and can manifest in laryngeal stridor due to impaired vocal fold motion, such as vocal fold abduction restriction, mostly referred to as vocal fold paresis, or paradoxical vocal fold adduction during inspiration. While the pathogenesis of laryngeal stridor is discussed controversially, its occurrence is clearly associated with reduced life expectancy. Before the clinical manifestation of laryngeal dysfunction however, abnormal vocal fold motion can already be seen in patients that might not yet fulfill the diagnostic criteria of MSA. In this article we summarize the current literature on pharyngolaryngeal findings in MSA and report preliminary findings from a pilot study investigating eight consecutive MSA patients. Patients showed varying speech abnormalities. Only 2/8 patients exhibited laryngeal stridor. However, during FEES, all patients presented with irregular arytenoid cartilages movements and vocal fold abduction restriction. 3/8 showed vocal fold fixation and 1/8 paradoxical vocal fold motion. All patients presented with oropharyngeal dysphagia, 5/8 with penetration or aspiration events. We suggest that specific abnormal vocal fold motion can help identifying MSA patients and may allow for delimiting this disorder from idiopathic PD. These findings therefore may serve as a novel clinical biomarker for MSA. Based on the available data and our preliminary clinical experience we developed a standardized easy-to-implement task-protocol to be performed during flexible endoscopic evaluation of swallowing (FEES) for detection of MSA-related pharyngolaryngeal movement disorders. Furthermore, we initiated a prospective study to evaluate the diagnostic utility of this protocol.

Occurrence of Stridor During Sleep in a Patient With Spinocerebellar Ataxia Type 17

ABSTRACT

Autosomal dominant spinocerebellar ataxia type 17 (SCA17) is known to have various manifestations. Previously, ataxia and autonomic dysfunction have been reported with this disorder, making an overlap with multiple systemic atrophy (MSA). However, respiratory complications, especially stridor during sleep, have not yet been reported with SCA17, in contrast to MSA, in which stridor occurs during sleep and is associated with an increased risk of death. Herein, we report a patient with SCA17, in whom stridor developed during sleep.

Stridor-related gray matter alterations in multiple system atrophy: A pilot study

INTRODUCTION

The neuroanatomical substrate of stridor associated with Multiple System Atrophy (MSA) remains unclear. We evaluated stridor-related gray matter (GM) changes in MSA.

METHODS

36 MSA patients underwent standardized nocturnal video-polysomnography and brain MRI. Differences in GM density between MSA patients with and without stridor and a sample of 22 matched healthy controls were evaluated with Voxel Based Morphometry protocol supplemented by a specific tool (SUIT) for analysing infratentorial structures.

RESULTS

Stridor was confirmed in 14 patients (10 MSA-cerebellar variant; 10 M; mean ± SD age = 61.6 ± 8.9years; disease duration = 5.2 ± 2.9years) and absent in 22 (11 MSA-cerebellar variant; 18 M; age = 61.4 ± 9.9years; disease duration = 4.8 ± 3.4years). Compared to MSA without stridor, patients with stridor showed higher GM density in the cerebellum (p < 0.05, corrected for the MSA-cerebellar variant and uncorrected when considering both MSA-variants) and lower in the striatum (p < 0.05, uncorrected).

CONCLUSIONS

This preliminary study has demonstrated for the first time in MSA stridor-related GM changes in striatal and cerebellar regions. Abnormalities in these regions were previously reported in dystonic disorders affecting laryngeal muscles, suggesting the hypothesis that stridor pathophysiology is dystonia-related. These results need however to be confirmed in a larger sample of patients.

Diagnosis of multiple system atrophy

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs.

Hypersomnia in Neurodegenerative Diseases

Hypersomnia is a common complaint in many patients with neurodegenerative diseases and a major cause of decreased quality of life. This article discusses the prevalence and factors associated with hypersomnia in patients with a variety of neurodegenerative diseases affecting the central nervous system, including tauopathies, synucleinopathies, and other conditions. Common nocturnal sleep problems that may result in daytime hypersomnia are delineated. A clinical approach to hypersomnia in patients with neurodegenerative diseases, recommended diagnostic testing, and available treatment options are also discussed.

[Expanding concept of clinical conditions and symptoms in multiple system atrophy]

Multiple system atrophy (MSA) is an adult-onset, progressive neurodegenerative disorder. MSA patients show various phenotypes during the course of their illness including parkinsonism, cerebellar ataxia, autonomic failure, and pyramidal signs. MSA is classified into the parkinsonian (MSA-P) or cerebellar (MSA-C) variant depending on the clinical motor phenotype at presentation. MSA-P and MSA-C are predominant in Western countries and Japan, respectively. The mean age at onset is 55 to 60 years. Prognosis ranges from 6 to 10 years, but some cases survive for more than 15 years. Early and severe autonomic failure is a poor prognostic factor. MSA patients sometimes present with isolated autonomic failure or motor symptoms/signs, and the median duration from onset to the concomitant appearance of motor and autonomic symptoms was approximately 2 years in our previous study. As the presence of the combination of motor and autonomic symptoms is essential for the current diagnostic criteria, early diagnosis is difficult when patients present with isolated autonomic failure or motor symptoms/signs. We experienced MSA patients who died before presentation of the motor symptoms/signs diagnostic for MSA (i.e., premotor MSA). Detection of the nature of autonomic failure consistent with MSA and identification of the dysfunctional anatomical sites may increase the probability of a diagnosis of premotor MSA. Dementia is another problem in MSA. Although dementia had been thought to be rare in MSA, frontal lobe dysfunction is observed frequently during the early course of the illness. Magnetic resonance imaging can show progressive cerebral atrophy in longstanding cases. More recently, MSA patients presenting with frontotemporal dementia preceding the presence of motor and autonomic manifestations diagnostic of MSA have been reported. Novel diagnostic criteria based on an expanding concept of the clinical conditions and symptoms of MSA will be needed for the development of disease-modifying therapies and better management.

Acoustic Characteristics of Stridor in Multiple System Atrophy

Nocturnal stridor is a breathing disorder prevalent in patients with multiple system atrophy (MSA). An improved understanding of this breathing disorder is essential since nocturnal stridor carries a poor prognosis (an increased risk of sudden death). In this study, we aimed to classify types of stridor by sound analysis and to reveal their clinical significance. Patients who met the criteria for probable MSA and had undergone polysomnography (PSG) were recruited. Patients were then assessed clinically with sleep questionnaires, including the Pittsburgh Sleep Quality Index, and the Hoehn and Yahr scale. Nocturnal stridor and snoring were analyzed with the Multi-Dimensional Voice Program. Nocturnal stridor was recorded in 22 patients and snoring in 18 patients using the PSG. Waveforms of stridors were classified into rhythmic or semirhythmic after analysis of the oscillogram. Formants and harmonics were observed in both types of stridor, but not in snoring. Of the 22 patients diagnosed with stridor during the present study, fifteen have subsequently died, with the time to death after the PSG study being 1.9 ± 1.4 years (range 0.8 to 5.0 years). The rhythmic waveform group presented higher scores on the Hoehn and Yahr scale and the survival outcome of this group was lower compared to the semirhythmic waveform group (p = 0.030, p = 0.014). In the Kaplan Meier's survival curve, the outcome of patients with rhythmic waveform was significantly less favorable than the outcome of patients with semirhythmic waveform (log-rank test, p < 0.001). Stridor in MSA can be classified into rhythmic and semirhythmic types and the rhythmic component signifies a poorer outcome.