An update on MSA: premotor and non-motor features open a window of opportunities for early diagnosis and intervention

Emotion Recognition in Multiple System Atrophy: An Exploratory Eye-Tracking Study

OBJECTIVE

Emotional processing is a core feature of social interactions and has been well studied in patients with idiopathic Parkinson's disease (PD), albeit with contradictory.

RESULTS

. However, these studies excluded patients with atypical parkinsonism, such as multiple system atrophy (MSA). The objective of this exploratory study was to provide better insights into emotion processing in patients with MSA using eye tracking data.

METHODS

We included 21 MSA patients, 15 PD patients and 19 matched controls in this study. Participants performed a dynamic and a static emotion recognition task, and gaze fixations were analyzed in different areas of interest. Participants underwent neuropsychological testing and assessment of depression and alexithymia.

RESULTS

MSA patients were less accurate in recognizing anger than controls (p = 0.02) and had overall fewer fixations than controls (p = 0.001). In the static task, MSA patients had fewer fixations (p < 0.001) and a longer time to first fixation (p = 0.026) on the eye region. Furthermore, MSA patients had a longer fixation duration overall than PD patients (p = 0.004) and longer fixations on the nose than controls (p = 0.005). Alexithymia scores were higher in MSA patients compared to controls (p = 0.038).

CONCLUSION

This study demonstrated impaired recognition of anger in MSA patients compared to HCs. Fewer and later fixations on the eyes along with a center bias suggest avoidance of eye contact, which may be a characteristic gaze behavior in MSA patients.

Data-Driven Subtypes of Multiple System Atrophy and Their Implications for Prognosis

Background

While multiple system atrophy (MSA) presents with high heterogeneous motor and nonmotor symptoms, the associations between clinical phenotypes and prognosis are unclear.

Objective

We aimed to evaluate clinical phenotypes of MSA using data-driven approach and measure the impact of phenotypes on survival and bedbound status.

Methods

193 MSA patients were recruited from Xuanwu Hospital Capital Medical University, whose history, motor and non-motor symptoms were examined using cluster analysis. Ninety-five participants were followed-up via telephone after a mean of 31.87 months. We employed Kaplan- Meier analysis to examine survival and performed Cox and logistic regression analyses to identify factors associated with survival and bedbound status.

Results

We identified four clinical profiles of MSA: cerebellar symptom-dominant, sleep and mood disorder-dominant, rigid akinetic-dominant, and malignant diffuse. The overall median survival was 7.75 years (95% CI 7.19-8.31). After adjusting for years from symptom onset to diagnosis, age and sex, patients in the malignant diffuse and rigid akinetic-dominant clusters had greater risk of death than sleep and mood disorder-dominant cluster. Furthermore, patients in the malignant diffuse and rigid akinetic-dominant clusters had higher risk of being bedbound than cerebellar symptom-dominant cluster.

Conclusions

The malignant diffuse and sleep and mood disorder-dominant were identified besides the two classical subtypes, parkinsonism, and cerebellar symptom-variant. Patients with rigid-akinetic motor profiles have a worse prognosis than cerebellar symptom-dominant profiles in general. Diffuse symptoms, especially postural instability, and cognitive alterations at diagnosis, indicate rapid functional loss and disease progression. The different profiles and prognoses might indicate varied underlying pathological mechanisms.

Comparison of tandospirone and escitalopram as a symptomatic treatment in Multiple System Atrophy-cerebellar ataxia: An open-label, non-controlled, 4 weeks observational study

BACKGROUND

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic failure and motor dysfunction in parkinsonism and/or cerebellar ataxia. Patients with MSA usually present with depression and anxiety symptoms. This observational study of patients with MSA-cerebellar subtype (MSA-C) with subthreshold depression/anxiety symptoms aimed to compare the efficacy of escitalopram oxalate (an antidepressant drug) and tandospirone citrate (an anxiolytic drug).

METHODS

Fifty-six MSA-C patients were included, with 28 patients in each treatment group. One group received escitalopram oxalate 10 mg/day and the other group received tandospirone citrate 30 mg/day. The patients were evaluated at baseline and after 4 weeks. Several psychiatric and neurological tests were performed, including the Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), Scale for the Assessment and Rating of Ataxia (SARA), and the Scale for Outcomes in Parkinson's Disease for Autonomic Symptoms (SCOPA-AUT). Furthermore, post-void residual urine volume (PVR) and blood pressure were measured.

RESULTS

There was a more substantial reduction in the HAMA/HAMD, scores of stance, finger tracking, and finger nose test in the SARA, and PVR in the tandospirone group. There was a more substantial reduction in scores of dysuria, light-headed when standing up, syncope and hyperhidrosis in the SCOPA-AUT in the escitalopram group (p's < 0.05).

CONCLUSIONS

Tandospirone citrate was more effective in improving depression/anxiety and some cerebellar ataxia symptoms, whereas escitalopram was more effective in improving some autonomic symptoms in MSA-C patients over a short-term period in an open-label observational study without a control group. Further research is needed to evaluate the long-term effects of tandospirone and escitalopram in MSA-C in long-term placebo controlled trials.

Deterioration of Cough, Respiratory, and Vocal Cord Functions in Patients with Multiple System Atrophy

The purpose of this study was to clarify changes in cough function in patients with multiple system atrophy (MSA). Seventeen probable patients with MSA were studied. Peak cough flow (PCF), respiratory function (percentage of vital capacity, percentage of forced vital capacity, and percentage of predicted forced expiratory volume in one second), respiratory muscle strength (percentage of maximal inspiratory mouth pressure and percentage of maximal expiratory mouth pressure), and maximum phonation time (MPT) were assessed. Walking ability, disease duration, possibility of air stacking, Unified MSA Rating Scale (UMSARS), and Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III were also assessed. Data were separately analyzed for ambulatory and non-ambulatory groups categorized by Functional Ambulation Categories. PCF, respiratory function, respiratory muscle strength, and MPT were significantly lower in the non-ambulatory group than in the ambulatory group. On the other hand, no correlation between PCF and disease duration was observed. A significant number of patients in the non-ambulatory group were unable to hold their breath. The UMSARS and MDS-UPDRS Part III in the non-ambulatory group were significantly higher than in the ambulatory group. It was concluded that ambulatory dysfunction is associated with the decline of cough function and respiratory-related function in patients with MSA.

Sleep Disorders Associated with Neurodegenerative Diseases

Sleep disturbances are common in various neurological pathologies, including amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), hereditary ataxias, Huntington's disease (HD), progressive supranuclear palsy (PSP), and dementia with Lewy bodies (DLB). This article reviews the prevalence and characteristics of sleep disorders in these conditions, highlighting their impact on patients' quality of life and disease progression. Sleep-related breathing disorders, insomnia, restless legs syndrome (RLS), periodic limb movement syndrome (PLMS), and rapid eye movement sleep behavior disorder (RBD) are among the common sleep disturbances reported. Both pharmacological and non-pharmacological interventions play crucial roles in managing sleep disturbances and enhancing overall patient care.

Diagnostic and prognostic performance of plasma neurofilament light chain in multiple system atrophy: a cross-sectional and longitudinal study

BACKGROUND

The longitudinal dynamics of neurofilament light chain (NfL) in multiple system atrophy (MSA) were incompletely illuminated. This study aimed to explore whether the plasma NfL (pNfL) could serve as a potential biomarker of clinical diagnosis and disease progression for MSA.

METHODS

We quantified pNfL concentrations in both a large cross-sectional cohort with 214 MSA individuals, 65 PD individuals, and 211 healthy controls (HC), and a longitudinal cohort of 84 MSA patients. Propensity score matching (PSM) was used to balance the age between the three groups. The pNfL levels between groups were compared using Kruskal-Wallis test. Linear mixed models were performed to explore the disease progression-associated factors in longitudinal MSA cohort. Random forest model as a complement to linear models was employed to quantify the importance of predictors.

RESULTS

Before and after matching the age by PSM, the pNfL levels could reliably differentiate MSA from HC and PD groups, but only had mild potential to distinguish PD from HC. By combining linear and nonlinear models, we demonstrated that pNfL levels at baseline, rather than the change rate of pNfL, displayed potential prognostic value for progression of MSA. The combination of baseline pNfL levels and other modifiers, such as subtypes, Hoehn-Yahr stage at baseline, was first shown to improve the diagnosis accuracy.

CONCLUSIONS

Our study contributed to a better understanding of longitudinal dynamics of pNfL in MSA, and validated the values of pNfL as a non-invasive sensitive biomarker for the diagnosis and progression. The combination of pNfL and other factors is recommended for better monitoring and prediction of MSA progression.

Gut-to-brain spreading of pathology in synucleinopathies: A focus on molecular signalling mediators

Synucleinopathies are a group of neurodegenerative disorders, classically characterized by the accumulation of aggregated alpha synuclein (aSyn) in the central nervous system. Parkinson's disease (PD) and multiple system atrophy (MSA) are the two prominent members of this family. Current treatment options mainly focus on the motor symptoms of these diseases. However, non-motor symptoms, including gastrointestinal (GI) symptoms, have recently gained particular attention, as they are frequently associated with synucleinopathies and often arise before motor symptoms. The gut-origin hypothesis has been proposed based on evidence of an ascending spreading pattern of aggregated aSyn from the gut to the brain, as well as the comorbidity of inflammatory bowel disease and synucleinopathies. Recent advances have shed light on the mechanisms underlying the progression of synucleinopathies along the gut-brain axis. Given the rapidly expanding pace of research in the field, this review presents a summary of the latest findings on the gut-to-brain spreading of pathology and potential pathology-reinforcing mediators in synucleinopathies. Here, we focus on 1) gut-to-brain communication pathways, including neuronal pathways and blood circulation, and 2) potential molecular signalling mediators, including bacterial amyloid proteins, microbiota dysbiosis-induced alterations in gut metabolites, as well as host-derived effectors, including gut-derived peptides and hormones. We highlight the clinical relevance and implications of these molecular mediators and their possible mechanisms in synucleinopathies. Moreover, we discuss their potential as diagnostic markers in distinguishing the subtypes of synucleinopathies and other neurodegenerative diseases, as well as for developing novel individualized therapeutic options for synucleinopathies.

Constipation in multiple system atrophy: a pilot study in Chinese patients

Objective

This study aimed to investigate the prevalence and clinical characteristics of subjective constipation in Chinese patients with multiple system atrophy (MSA), as well as the timing of constipation onset relative to the occurrence of motor symptoms.

Methods

A total of 200 patients who were consecutively admitted to two large Chinese hospitals from February 2016 to June 2021 and subsequently diagnosed with probable MSA were enrolled in this cross-sectional study. Demographic and constipation-related clinical data were collected, and motor and non-motor symptoms were assessed using various scales and questionnaires. Subjective constipation was defined using ROME III criteria.

Results

The frequency of constipation was 53.5, 59.7, and 39.3% in MSA, MSA with predominately parkinsonism (MSA-P), and MSA with predominately cerebellar ataxia (MSA-C), respectively. MSA-P subtype and high total UMSARS scores were associated with constipation in MSA. Similarly, the high total UMSARS scores were associated with constipation in MSA-P and MSA-C patients. Among the 107 patients with constipation, 59.8% began experiencing it before the onset of motor symptoms, and the interval between constipation and occurrence of motor symptoms was significantly longer in these patients than in those who experienced constipation after onset of motor symptoms.

Conclusion

Constipation is a highly prevalent non-motor symptom in MSA and more often occurs before the onset of motor symptoms. The results of this study may help guide future research into MSA pathogenesis in its earliest stages.

Factors impacting quality of life in multiple system atrophy

Background

Multiple system atrophy (MSA) is an atypical parkinsonian disorder marked by autonomic dysfunction, parkinsonism, cerebellar dysfunction, and poor response to dopaminergic medications such as levodopa. Patient-reported quality of life is an important benchmark for clinicians and clinical trials. The Unified Multiple System Atrophy Rating Scale (UMSARS) allows healthcare providers to rate and assess MSA progression. The MSA-QoL questionnaire is a health-related quality of life scale intended to provide patient-reported outcome measures. In this article, we investigated inter-scale correlations between the MSA-QoL and UMSARS to determine factors impacting the quality of life of patients with MSA.

Methods

Twenty patients at the Johns Hopkins Atypical Parkinsonism Center's Multidisciplinary Clinic with a diagnosis of clinically probable MSA and who filled out the MSA-QoL and UMSARS questionnaires within 2 weeks of each other were included. Inter-scale correlations between MSA-QoL and UMSARS responses were examined. Linear regressions were also performed to examine relationships between both scales.

Results

Significant inter-scale correlations were found between the MSA-QoL and UMSARS, both between MSA-QoL total score and UMSARS Part I subtotal scores and for individual scale items. There were no significant correlations between MSA-QoL life satisfaction rating and UMSARS subtotal scores or any specific UMSARS items. Linear regression analysis found significant associations between MSA-QoL total score and UMSARS Part I and total scores, and between MSA-QoL life satisfaction rating and UMSARS Part I, Part II, and total scores (after adjustment for age).

Conclusions

Our study demonstrates significant inter-scale correlations between MSA-QoL and UMSARS, particularly relating to activities of daily living and hygiene. MSA-QoL total score and UMSARS Part I subtotal scores, which assess patients' functional status, were significantly correlated. The lack of significant associations between MSA-QoL life satisfaction rating and any UMSARS item suggests there may be aspects to quality of life that are not fully captured by this assessment. Larger cross-sectional and longitudinal analyses utilizing UMSARS and MSA-QoL are warranted and modification of the UMSARS should be considered.

Coenzyme Q10: Role in Less Common Age-Related Disorders

In this article we have reviewed the potential role of coenzyme Q10 (CoQ10) in the pathogenesis and treatment of a number of less common age-related disorders, for many of which effective therapies are not currently available. For most of these disorders, mitochondrial dysfunction, oxidative stress and inflammation have been implicated in the disease process, providing a rationale for the potential therapeutic use of CoQ10, because of its key roles in mitochondrial function, as an antioxidant, and as an anti-inflammatory agent. Disorders reviewed in the article include multi system atrophy, progressive supranuclear palsy, sporadic adult onset ataxia, and pulmonary fibrosis, together with late onset versions of Huntington’s disease, Alexander disease, lupus, anti-phospholipid syndrome, lysosomal storage disorders, fibromyalgia, Machado-Joseph disease, acyl-CoA dehydrogenase deficiency, and Leber’s optic neuropathy.

Microbiota- Brain-Gut-Axis Relevance to Parkinson's Disease: Potential Therapeutic Effects of Probiotics

Parkinson's disease (PD) is the second most common type of neurogenerative disease among middleaged and older people, characterized by aggregation of alpha-synuclein and dopaminergic neuron loss. The microbiota- gut-brain axis is a dynamic bidirectional communication network and is involved in the pathogenesis of PD. The aggregation of misfolded protein alpha-synuclein is a neuropathological characteristic of PD, originates in the gut and migrates to the central nervous system (CNS) through the vagus nerve and olfactory bulb. The change in the architecture of gut microbiota increases the level short-chain fatty acids (SCFAs) and other metabolites, acting on the neuroendocrine system and modulating the concentrations of gamma-Aminobutyric acid (GABA), serotonin, and other neurotransmitters. It also alters the vagus and intestinal signalling, influencing the brain and behaviour by activating microglia and systemic cytokines. Both experimental and clinical reports indicate the role of intestinal dysbiosis and microbiota host interaction in neurodegeneration. Probiotics are live microorganisms that modify the gut microbiota in the small intestine to avoid neurological diseases. Probiotics have been shown in clinical and preclinical studies to be effective in the treatment of PD by balancing the gut microbiota. In this article, we described the role of gut-microbiota in the pathogenesis of PD. The article aims to explore the mechanistic strategy of the gut-brain axis and its relation with motor impairment and the use of probiotics to maintain gut microbial flora and prevent PD-like symptoms.

Abnormal circadian blood pressure regulation and cognitive impairment in α-synucleinopathies

Circadian blood pressure (BP) rhythm is important for the maintenance of healthy daily life, and its disruption is associated with poor outcomes. Cardiovascular autonomic failure is often observed in older populations but has a greater impact on neurodegenerative disorders such as α-synucleinopathies. These BP abnormalities include orthostatic hypotension (OH), supine hypertension (SH), and a loss of nocturnal BP fall. OH not only causes falls or syncope but is also related to cognitive impairment in α-synucleinopathies. For example, OH doubles or triples the risk for the development of cognitive impairment in Parkinson's disease (PD). The diffuse central and peripheral neuropathology of α-synuclein may contribute to both OH and cognitive impairment. Moreover, repeated cerebral hypoperfusion in OH is thought to be related to cerebrovascular and neuronal damage, which may cause cognitive impairment. SH, which often coexists with OH, is also associated with cognitive impairment through cerebrovascular damage, such as white matter lesions and cerebral microbleeds. The reverse-dipping (riser) pattern on ambulatory BP monitoring is commonly observed in PD (∼56%), regardless of disease duration and severity. It is also related to cognitive impairment and more pronounced when coexisting with OH. These abnormal circadian BP profiles may be synergistically associated with cognitive impairment and poor outcomes in α-synucleinopathies. Although evidence for aggressive control of BP dysregulation improving cognitive impairment and outcomes is limited, regular BP monitoring appears to be important for total management of α-synucleinopathies.

Prospective CERAD Neuropsychological Assessment in Patients With Multiple System Atrophy

The objective of the study was to characterize the pattern of cognitive dysfunction in patients with multiple system atrophy (MSA) applying a standardized neuropsychological assessment. A total of 20 patients with the diagnosis of probable or possible MSA were enrolled for neuropsychological assessment applying the CERAD plus battery. All patients were tested at baseline and 14/20 patients received additional follow-up assessments (median follow-up of 24 months). Additionally, relationship between cortical thickness values/subcortical gray matter volumes and CERAD subitems was evaluated at baseline in a subgroup of 13/20 patients. Trail Making Test (TMT) was the most sensitive CERAD item at baseline with abnormal performance (z-score < −1.28) in one or both pathological TMT items (TMT-A, TMT-B) in 60% of patients with MSA. Additionally, there was a significant inverse correlation between the volume of the left and the right accumbens area and the TMT A item after adjusting for age (left side: p = 0.0009; right side p = 0.003). Comparing both subtypes, patients with MSA-C had significant lower values in phonemic verbal fluency (p = 0.04) and a trend for lower values in semantic verbal fluency (p = 0.06) compared to MSA-P. Additionally, patients with MSA-C showed significantly worse performance in the TMT-B task (p = 0.04) and a trend for worse performance in the TMT-A task (p = 0.06). Concerning longitudinal follow-up, a significant worsening in the TMT-B (p = 0.03) can be reported in MSA. In conclusion, frontal-executive dysfunction presents the hallmark of cognitive impairment in MSA.

Pre-diagnostic presentations of Multiple System Atrophy case control study in a primary care dataset

BACKGROUND

We here report the pre-diagnostic clinical presentations of patients with Multiple System Atrophy (MSA) from analysis of a large routine clinical care database.

METHODS

Data were extracted from a primary care database in the German healthcare system for the period between January 2000 and December 2020. We identified 250 patients with new diagnosis of MSA and 250 controls matched for age, sex, and index year. Logistic regression analyses were conducted to assess association between MSA and predefined diagnoses.

RESULTS

The greatest rate increase in the 2 years preceding diagnosis of MSA was seen for hypotension and balance impairment but rates of memory problems, urinary dysfunction, dizziness and depression rates were also markedly increased, and ataxia was solely identified in those with a later diagnosis of MSA. Up to 5 years before diagnosis similar patterns were seen, but >5 years before diagnosis only depression rates were increased with a trend for increase in constipation.

CONCLUSIONS

Presentations that were significantly more common in patients with MSA in the pre-diagnostic phase than in controls were autonomic complaints such as postural hypotension, urinary and bowel dysfunction, and early balance impairment. However, the study also highlights that memory complaints and depression may be early features of MSA years before diagnosis.

The Non-motor Symptoms, Disability Progression, and Survival Analysis of Atypical Parkinsonism: Case Series from Eastern India and Brief Review of Literature

Objective The objectives of this study are (1) to describe the non-motor profile, the motor disability progression, and survival analysis of atypical parkinsonism in a tertiary care hospital of eastern India and (2) to elucidate the neurocircuitry and the putative substrates responsible for non-motor manifestations.

Methods In this prospective observational study, patients were diagnosed based on Consensus Criteria for Progressive Supranuclear Palsy (PSP), The Fourth Consensus Report of the Dementia with Lewy Body (DLBD) Consortium 2017, The Autonomic Neuroscience 2018 Criteria for Multiple System Atrophy (MSA), and Armstrong 2013 Criteria for Corticobasal Degeneration (CBD). Disease severity was assessed at baseline and 6 months of follow-up using the Unified Parkinson's Disease Rating Scales (UPDRS). For PSP and MSA, the PSP-Clinical Deficits Scale (PSP-CDS) and the Unified MSA Rating Scale (UMSARS), respectively, were used. Cox regression analysis and the hazard ratio were calculated.

Results Out of 27 patients, the diagnosis was probable PSP in 12, probable MSA in 7, probable CBD in 5, and probable DLBD in 3. Non-motor symptoms were highly prevalent across all subtypes. Motor disability progression as assessed by UPDRS parts 2 and 3 showed significant deterioration over 6-month follow-up across all groups (p < 0.05). Disease progression assessed by PSP-CDS and UMSARS over 6 months was significant (p < 0.05). One PSP and two MSA patients died during a 6-month follow-up period. The hazard ratio in MSA was 3.5 (95% confidence interval: 0.31–0.38) with p = 0.306.

Conclusion Atypical parkinsonian disorders are rare, and usually more severe than idiopathic parkinsonism. As no definitive treatment is available, symptomatic management involving a multidisciplinary team approach must be prioritized.

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS): from clinical diagnosis towards genetic testing

The cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is a late-onset and recessively inherited ataxia. For many years, CANVAS has been diagnosed based on the clinical phenotype. Only recently, a large biallelic pentanucleotide repeat expansion in the replication factor C subunit 1 (RFC1) gene has been identified as the underlying genetic cause for the large majority of CANVAS cases. Subsequently, other phenotypes such as ataxia with chronic cough, incomplete CANVAS and MSA-C-like phenotypes have been associated with biallelic RFC1 repeat expansions. Because of this heterogeneity it has been suggested to change the name of the disease to "RFC1 disease". Chronic cough is characteristic and can precede neurological symptoms by years or decades. In the neurological examination signs of cerebellar, sensory, and vestibular ataxia are frequently observed. Nerve conduction studies usually show absent or markedly reduced sensory nerve action potentials. On brain MRI cerebellar degeneration and spinal cord alterations are common. In later disease stages more widespread neurodegeneration with additional involvement of the brainstem and basal ganglia is possible. As yet, the exact incidence of RFC1-associated neurological diseases remains uncertain although first studies suggest that RFC1-related ataxia is common. Moreover, the pathophysiological mechanisms caused by the large biallelic pentanucleotide repeat expansions in RFC1 remain elusive. Future molecular and genetic research as well as natural history studies are highly desirable to pave the way towards personalized treatment approaches.

Respiratory and sleep-related complications of multiple system atrophy

PURPOSE OF REVIEW

The purpose of this article is to provide a contemporary review of sleep issues affecting patients with multiple system atrophy (MSA).

RECENT FINDINGS

Prodromal symptoms of MSA may occur years prior to diagnosis, including autonomic dysfunction such as orthostatic hypotension, urogenital dysfunction, rapid eye movement (REM) sleep behavior disorder (RBD), and stridor. Patients may also develop sleep-related respiratory disorders such as obstructive sleep apnea (OSA), central sleep apnea (CSA), and stridor. The development of stridor is associated with a shortened lifespan and sudden death, which may be further accelerated by autonomic instability. MSA appears to follow a 'prion-like' disease progression.

SUMMARY

MSA is a rapidly progressive neurodegenerative disease characterized by a combination of autonomic failure and motor symptoms. MSA is often misdiagnosed as the initial presentation mimics other neurodegenerative disorders. There are diagnostic criteria to identify possible, probable, and definite MSA. Prodromal symptoms may occur years prior to diagnosis, including autonomic dysfunction such as orthostatic hypotension, urogenital dysfunction, REM RBD, and stridor. In previous years, treatment consisted of tracheostomy but did not address the component of CSA, which commonly coexisted or developed later because of destruction of medullary chemoreceptors. Positive airway pressure may be as effective as tracheostomy alone in ameliorating obstruction at the vocal cord level.