ALS with respiratory onset: clinical features and effects of non-invasive ventilation on the prognosis

Sex Differences in Amyotrophic Lateral Sclerosis Survival and Progression: A Multidimensional Analysis

OBJECTIVE

To investigate sex-related differences in amyotrophic lateral sclerosis (ALS) prognosis and their contributing factors.

METHODS

Our primary cohort was the Piemonte and Aosta Register for ALS (PARALS); the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) and the Answer ALS databases were used for validation. Survival analyses were conducted accounting for age and onset site. The roles of forced vital capacity and weight decline were explored through a causal mediation analysis. Survival and disease progression rates were also evaluated after propensity score matching.

RESULTS

The PARALS cohort included 1,890 individuals (44.8% women). Men showed shorter survival when stratified by onset site (spinal onset HR 1.20, 95% CI 1.00-1.44, p = 0.0439; bulbar onset HR 1.36, 95% CI 1.09-1.70, p = 0.006917), although women had a steeper functional decline (+0.10 ALSFRS-R points/month, 95% CI 0.07-0.15, p < 0.00001) regardless of onset site. Instead, men showed worse respiratory decline (-4.2 forced vital capacity%/month, 95% CI -6.3 to -2.2, p < 0.0001) and faster weight loss (-0.15 kg/month, 95% CI -0.25 to -0.05, p = 0.0030). Causal mediation analysis showed that respiratory function and weight loss were pivotal in sex-related survival differences. Analysis of patients from PRO-ACT (n = 1,394, 40.9% women) and Answer ALS (n = 849, 37.2% women) confirmed these trends.

INTERPRETATION

The shorter survival in men is linked to worse respiratory function and weight loss rather than a faster disease progression. These findings emphasize the importance of considering sex-specific factors in understanding ALS pathophysiology and designing tailored therapeutic strategies. ANN NEUROL 2024;96:159-169.

Evaluation of the therapeutic effects of rehabilitation therapy on patients with amyotrophic lateral sclerosis-a meta-analysis

Objective

To investigate the effect of rehabilitation therapy on the global function, respiratory function, and quality of life in patients with amyotrophic lateral sclerosis (ALS).

Methods

PubMed, Web of Science, and The National Library of Medicine (NLM) were systematically searched and the search period was between the date of database establishment and December 31, 2023. The outcome measures finally analyzed included the ALS functional rating scale/revised (ALSFRS/ALSFRS-R), forced vital capacity percentage predicted (FVC%), fatigue severity scale (FSS), and maximal expiratory pressure (MEP).

Results

A total of 13 randomized controlled trials (RCTs) were included, and 5 outcome measures were pooled and analyzed. A total of 657 patients with ALS were enrolled, with 299 in the experimental group (rehabilitation therapy, such as resistance training, endurance training, aerobic training, respiratory muscle training, and standard rehabilitation therapy) and 358 in the control group (conventional interventions, such as simple joint movements or daily stretching). The ALSFRS scores were better in the experimental group than in the control group at 0-4 months (MD = 3.36, 95% CI: 0.82, 5.91, Z = 2.59, p = 0.009) and at 5-8 months (MD = 5.00, 95% CI: -2.42, 7.58, Z = 3.80, p < 0.001). Moreover, the ALSFRS-R scores of the experimental group was better than that of the control group at 5-8 months (MD = 2.83, 95% CI: 1.21, 4.45, Z = 3.42, p < 0.001) and 9-12 months (MD = 1.87, 95% CI: -0.37, 4.11, Z = 1.63, p = 0.10). It was also found that the MEP value of the experimental group was significantly better than that of the control group after intervention (MD = 18.49, 95% CI: 1.47, 35.50, Z = 2.13, p = 0.03). However, there were no significant differences in FVC% value and FSS scores at 0-5 months and 6-12 months between the two groups.

Conclusion

Rehabilitation therapy is helpful in improving the short-, medium-, and long-term global function score of patients with ALS, with positive effects on respiratory function.

Peripheral nervous system and neuromuscular disorders in the emergency department: A review

INTRODUCTION

Acute presentations and emergencies in neuromuscular disorders (NMDs) often challenge clinical acumen. The objective of this review is to refine the reader's approach to history taking, clinical localization and early diagnosis, as well as emergency management of neuromuscular emergencies.

METHODS

An extensive literature search was performed to identify relevant studies. We prioritized meta-analysis, systematic reviews, and position statements where possible to inform any recommendations.

SUMMARY

The spectrum of clinical presentations and etiologies ranges from neurotoxic envenomation or infection to autoimmune disease such as Guillain-Barré Syndrome (GBS) and myasthenia gravis (MG). Delayed diagnosis is not uncommon when presentations occur "de novo," respiratory failure is dominant or isolated, or in the case of atypical scenarios such as GBS variants, severe autonomic dysfunction, or rhabdomyolysis. Diseases of the central nervous system, systemic and musculoskeletal disorders can mimic presentations in neuromuscular disorders.

CONCLUSIONS

Fortunately, early diagnosis and management can improve prognosis. This article provides a comprehensive review of acute presentations in neuromuscular disorders relevant for the emergency physician.

"De Novo" Hypercapnic Respiratory Failure Unmasking Neuromuscular Disorders: Experiences From a Tertiary Care Center and Review of Literature

OBJECTIVES

Neuromuscular disorders could have respiratory involvement early or late into illness. Rarely, patients may present with a hypercapnic respiratory failure (with minimal motor signs) unmasking an underlying disease. There are hardly any studies which have addressed the spectrum and challenges involved in management of this subset, especially in the real-world scenario.

METHODS

A retrospective study comprising consecutive patients hospitalized with hypercapnic respiratory failure as the sole/dominant manifestation. The clinical-electrophysiological spectrum, phrenic conductions, diaphragm thickness, and outcomes were analyzed.

RESULTS

Twenty-seven patients were included, the mean age was 47.29 (SD 15.22) years, and the median duration of respiratory symptoms was 2 months (interquartile range [IQR] 1-4). Orthopnea was present in 23 patients (85.2%) and encephalopathy in 8 patients (29.6%). Phrenic nerve latencies and amplitudes were abnormal in 83.3% and 95.6%, respectively. Abnormal diaphragm thickness was noted in 78.5%. Based on a comprehensive electrophysiological strategy and paraclinical tests, an etiology was established in all. Reversible etiologies were identified in 17 patients (62.9%). These included myasthenia gravis (anti-AChR and MuSK), inflammatory myopathy, riboflavin transporter deficiency neuronopathy, Pompe disease, bilateral phrenic neuritis, and thyrotoxicosis. Respiratory onset motor neuron disease was diagnosed in 8 patients (29.6%). Despite diaphragmatic involvement, a functional respiratory recovery was noted at discharge (45%) and last follow-up (60%). Predictors for good outcomes included female sex, normal nerve conductions, and recent-onset respiratory symptoms.

DISCUSSION

A good functional recovery was noted in most of the patients including respiratory onset motor neuron disease. A systematic algorithmic approach helps in proper triaging, early diagnosis, and treatment. Clinical and electrodiagnostic challenges and observations from a tertiary care referral center are discussed.

Generation of human iPSC-derived phrenic-like motor neurons to model respiratory motor neuron degeneration in ALS

The fatal motor neuron (MN) disease Amyotrophic Lateral Sclerosis (ALS) is characterized by progressive MN degeneration. Phrenic MNs (phMNs) controlling the activity of the diaphragm are prone to degeneration in ALS, leading to death by respiratory failure. Understanding of the mechanisms of phMN degeneration in ALS is limited, mainly because human experimental models to study phMNs are lacking. Here we describe a method enabling the derivation of phrenic-like MNs from human iPSCs (hiPSC-phMNs) within 30 days. This protocol uses an optimized combination of small molecules followed by cell-sorting based on a cell-surface protein enriched in hiPSC-phMNs, and is highly reproducible using several hiPSC lines. We show further that hiPSC-phMNs harbouring ALS-associated amplification of the C9orf72 gene progressively lose their electrophysiological activity and undergo increased death compared to isogenic controls. These studies establish a previously unavailable protocol to generate human phMNs offering a disease-relevant system to study mechanisms of respiratory MN dysfunction.

Neuroprognostication for Patients with Amyotrophic Lateral Sclerosis: An Updated, Evidence-Based Review

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder that presents and progresses in various ways, making prognostication difficult. Several paradigms exist for providers to elucidate prognosis in a way that addresses not only the amount of time a patient has to live, but also a patient's quality of their life moving forward. Prognostication, with regard to both survivability and quality of life, is impacted by several features that include, but are not limited to, patient demographics, clinical features on presentation, and over time, access to therapy, and access to multidisciplinary clinics. An understanding of the impact that these features have on the life of a patient with ALS can help providers to develop a better and more personalized approach for patients related to their clinical prognosis after a diagnosis is made. The ultimate goal of prognostication is to empower patients with ALS to take control and make decisions with their care teams to ensure that their goals are addressed and met.

Kaempferol, a potential neuroprotective agent in neurodegenerative diseases: From chemistry to medicine

Neurodegenerative diseases (NDDs) encompass a range of conditions that involve progressive deterioration and dysfunction of the nervous system. Some of the common NDDs include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Although significant progress has been made in understanding the pathological mechanisms of NDDs in recent years, the development of targeted and effective drugs for their treatment remains challenging. Kaempferol is a flavonoid whose derivatives include kaempferol-O-rhamnoside, 3-O-β-rutinoside/6-hydroxykaempferol 3,6-di-O-β-d-glucoside, and kaempferide. Emerging studies have suggested that kaempferol and its derivatives possess neuroprotective properties and may have potential therapeutic benefits in NDDs. Here, we aimed to provide a theoretical basis for the use of kaempferol and its derivatives in the clinical treatment of NDDs. We systematically reviewed the literature in the PubMed, Web of Science, and Science Direct databases until June 2022 using the search terms "kaempferol," "kaempferol derivatives," "NDDs," "pharmacokinetics," and "biosynthesis" according to the reporting items for systematic review (PRISMA) standard. Based on combined results of in vivo and in vitro studies, we summarize the basic mechanisms and targets of kaempferol and its derivatives in the management of AD, PD, HD, and ALS. Kaempferol and its derivatives exert a neuroprotective role mainly by preventing the deposition of amyloid fibrils (such as Aβ, tau, and α-synuclein), inhibiting microglia activation, reducing the release of inflammatory factors, restoring the mitochondrial membrane to prevent oxidative stress, protecting the blood-brain barrier, and inhibiting specific enzyme activities (such as cholinesterase). Kaempferol and its derivatives are promising natural neuroprotective agents. By determining their pharmacological mechanism, kaempferol and its derivatives may be new candidate drugs for the treatment of NDDs.

Diagnostic delay in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease, and the time from symptom onset to diagnosis remains long. With the advent of disease-modifying treatments, the need to identify and diagnose ALS in a timely fashion has never been greater.

METHODS

We reviewed the literature to define the severity of ALS diagnostic delay, the various factors that contribute to this delay (including patient and physician factors), and the role that site of symptom onset plays in a patient's diagnostic journey.

RESULTS

Diagnostic delay is influenced by general practitioners' lack of recognition of ALS due to disease rarity and heterogenous presentations. As a result, patients are referred to non-neurologists, have unnecessary diagnostic testing, and may ultimately be misdiagnosed. Patient factors include their illness behavior-which impacts diagnostic delay-and their site of symptom onset. Limb-onset patients have the greatest diagnostic delay because they are frequently misdiagnosed with degenerative spine disease or peripheral neuropathy.

CONCLUSION

Prompt ALS diagnosis results in more effective clinical management, with earlier access to disease-modifying therapies, multidisciplinary care, and, if desired, clinical trial involvement. Due to lack of commercially available ALS biomarkers, alternative strategies to identify and triage patients who likely have ALS must be employed. Several diagnostic tools have been developed to encourage general practitioners to consider ALS and make an urgent referral to ALS specialists, bypassing unnecessary referrals to non-neurologists and unnecessary diagnostic workup.

Respiratory onset in amyotrophic lateral sclerosis: clinical features and spreading pattern

Objective To describe the clinical features and progression of patients with respiratory onset amyotrophic lateral sclerosis (ALS). Methods: We analyzed the clinical features, including respiratory tests, functional score, noninvasive ventilation (NIV) time and survival of ALS patients with respiratory-onset in our database consisting of 1688 patients. In a subset of 625 ALS patients we analyzed the spreading pattern to other bodily regions. Results: We included 1579 patients with ALS. Sixty-three patients (4%) presented respiratory-onset (79.4% men, mean onset-age 67.7 ± 8.9yrs). All had predominant LMN involvement, and significant weight loss (>10%) was identified in 38.9%. The respiratory tests were abnormal in these respiratory-onset patients (p < 0.001). ALSFRS-R respiratory subscore was lower in this population (p < 0.001). NIV was adapted in 84.1%, sooner than in the larger group of ALS patients (p < 0.001), and survival from disease onset was shorter (p < 0.001). Respiratory-onset was a predictor of time to NIV (X²=42.0, p < 0.001) and of survival (X²=7.1, p = 0.008). The spreading pattern was studied in 18 patients with isolated respiratory-onset. The progression interval to the 2nd region was 4.7 ± 5.7mo and to a 3rd region 6.1 ± 8.7mo. Different patterns of spread had no impact on survival. Conclusions: This phenotype is typically seen in emaciated older men with predominant lower motor neuron involvement, and is associated with diaphragm paresis and central respiratory involvement. NIV adaptation is rapid but total survival is shorter than in the other patients. Spreading pattern did not affect time to NIV adaptation or total survival, as NIV support is a modifying treatment in the course of ALS.

Different observation period of exercise training in amyotrophic lateral sclerosis patients: A meta-analysis

Objective

The purpose of this meta-analysis was to evaluate the effect of more intensive exercise training on the functional ability of patients with amyotrophic lateral sclerosis.

Methods

Randomized controlled trials on exercise training in amyotrophic lateral sclerosis patients were retrieved from PubMed, Embase, Web of Science, Cochrane Library and other databases, and meta-analysis was conducted using a fixed effect model or random effect model. Sensitivity analysis was used as a means to study heterogeneity.

Results

A total of 8 randomized controlled trials involving 330 patients with amyotrophic lateral sclerosis were included in this study. The results showed that there was statistical significance in the influence of more intensive exercise training on amyotrophic lateral sclerosis Functional Rating Scale in the short term (0–4 months) and the medium term (5–8 months) (P &lt; 0.05). There was no significant difference in the effect of the amyotrophic lateral sclerosis Functional Rating Scale-Revised in the short term (0–4 months) or long term (9–12 months) (P ≥ 0.05). In the medium term (5–8 months), there was statistical significance (P &lt; 0.05). There was no significant difference in Forced vital capacity (FVC%) in the short term (0–4 months) (P &gt; 0.05).

Conclusion

More intensive exercise training may slow the decline in functional score of amyotrophic lateral sclerosis patients, and more studies should be carried out in the future to verify the effect of more intensive exercise training in patients with amyotrophic lateral sclerosis.

Stress Granule Homeostasis, Aberrant Phase Transition, and Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. In recent years, a large number of ALS-related mutations have been discovered to have a strong link to stress granules (SGs). SGs are cytoplasmic ribonucleoprotein condensates mediated by liquid-liquid phase separation (LLPS) of biomacromolecules. They help cells cope with stress. The normal physiological functions of SGs are dependent on three key aspects of SG "homeostasis": SG assembly, disassembly, and SG components. Any of these three aspects can be disrupted, resulting in abnormalities in the cellular stress response and leading to cytotoxicity. Several ALS-related pathogenic mutants have abnormal LLPS abilities that disrupt SG homeostasis, and some of them can even cause aberrant phase transitions. As a result, ALS-related mutants may disrupt various aspects of SG homeostasis by directly disturbing the intermolecular interactions or affecting core SG components, thus disrupting the phase equilibrium of the cytoplasm during stress. Considering that the importance of the "global view" of SG homeostasis in ALS pathogenesis has not received enough attention, we first systematically summarize the physiological regulatory mechanism of SG homeostasis based on LLPS and then examine ALS pathogenesis from the perspective of disrupted SG homeostasis and aberrant phase transition of biomacromolecules.

A Japanese Patient with Hereditary Myopathy with Early Respiratory Failure Due to the p.P31732L Mutation of Titin

Hereditary myopathy with early respiratory failure (HMERF) is caused by titin A-band mutations in exon 344 and is considered quite rare. Respiratory insufficiency can be the sole symptom in the disease course. We herein report the first Japanese HMERF patient with a p.P31732L mutation in titin. The patient manifested respiratory failure and mild weakness of the neck flexor muscle at 69 years old and showed fatty replacement of the bilateral semitendinosus muscles on muscle imaging. Our case indicates that HMERF with a heterozygous p.P31732L mutation should be included in the differential diagnosis of muscular diseases presenting with early respiratory failure.

Clinical and electrophysiological characteristics of respiratory onset amyotrophic lateral sclerosis: a single-centre study

BACKGROUND

We compared the clinical characteristics of patients with respiratory, bulbar and limb onset amyotrophic lateral sclerosis (ALS) who visited a single tertiary centre for 8 years.

METHODS

Total of 115 ALS patients with respiratory, bulbar and limb onset ALS, including sex, body mass index (BMI), presence of lung disease, age at diagnosis, disease duration after initial symptoms, ALS Functional Rating Scale (ALSFRS-R) and progression rate (Delta-FS), pulmonary function, amplitude and distal latency (DL) of the phrenic nerves and blood creatine kinase (CK) and uric acid levels were collected.

RESULTS

The prevalence of respiratory, bulbar and limb onset ALS were 5.2%, 28.7% and 66.1%, respectively. The mean age at diagnosis and ALSFRS-R were 67.8 ± 5.5, 63.8 ± 10.1 and 59.2 ± 11.7 in the descending order. The mean amplitude (0.18 ± 0.10 mV) and DL (9.5 ± 1.7 ms) of the phrenic nerves were significantly decreased and prolonged in respiratory onset ALS compared with other types of ALS patients. Patients with respiratory onset ALS had normal creatine kinase (CK) levels, whereas patients with other types of ALS had increased CK levels.

CONCLUSIONS

Although rare, respiratory onset ALS may occur and should be considered during the initial differential diagnosis. In this study, patients with respiratory onset ALS were characterised by male predominance, with a higher baseline ALSFRS-R, lower BMI and phrenic nerve study well discriminated respiratory onset ALS from bulbar or limb onset ALS patients.

Structural variation analysis of 6,500 whole genome sequences in amyotrophic lateral sclerosis

There is a strong genetic contribution to Amyotrophic lateral sclerosis (ALS) risk, with heritability estimates of up to 60%. Both Mendelian and small effect variants have been identified, but in common with other conditions, such variants only explain a little of the heritability. Genomic structural variation might account for some of this otherwise unexplained heritability. We therefore investigated association between structural variation in a set of 25 ALS genes, and ALS risk and phenotype. As expected, the repeat expansion in the C9orf72 gene was identified as associated with ALS. Two other ALS-associated structural variants were identified: inversion in the VCP gene and insertion in the ERBB4 gene. All three variants were associated both with increased risk of ALS and specific phenotypic patterns of disease expression. More than 70% of people with respiratory onset ALS harboured ERBB4 insertion compared with 25% of the general population, suggesting respiratory onset ALS may be a distinct genetic subtype.

Noninvasive and invasive mechanical ventilation for neurologic disorders

Patients with acute neurologic injuries frequently require mechanical ventilation due to diminished airway protective reflexes, cardiopulmonary failure secondary to neurologic insults, or to facilitate gas exchange to precise targets. Mechanical ventilation enables tight control of oxygenation and carbon dioxide levels, enabling clinicians to modulate cerebral hemodynamics and intracranial pressure with the goal of minimizing secondary brain injury. In patients with acute spinal cord injuries, neuromuscular conditions, or diseases of the peripheral nerve, mechanical ventilation enables respiratory support under conditions of impending or established respiratory failure. Noninvasive ventilatory approaches may be carefully considered for certain disease conditions, including myasthenia gravis and amyotrophic lateral sclerosis, but may be inappropriate in patients with Guillain-Barré syndrome or when relevant contra-indications exist. With regard to discontinuing mechanical ventilation, considerable uncertainty persists about the best approach to wean patients, how to identify patients ready for extubation, and when to consider primary tracheostomy. Recent consensus guidelines highlight these and other knowledge gaps that are the focus of active research efforts. This chapter outlines important general principles to consider when initiating, titrating, and discontinuing mechanical ventilation in patients with acute neurologic injuries. Important disease-specific considerations are also reviewed where appropriate.

A Brazilian multicentre study on the clinical and epidemiological profiles of 1116 patients with amyotrophic lateral sclerosis and its phenotypic variants

Objective: We conducted a multicentre, cross-sectional analysis of Brazilian patients with amyotrophic lateral sclerosis (ALS) and its phenotypic variants. We describe and compare their clinical and epidemiological data. Methods: We collected data from 1,116 patients who visited seven rehabilitation hospitals in the SARAH network from 1 January 2009 to 20 March 2020. This representative sample of patients was from 308 cities in 25 states from the country's five regions. Results: The median age at onset was 55 years, and we found a significant linear correlation between the age at onset and the Municipal Human Development Index (MHDI) but not survival time. We found a four-year difference using a cutoff value of 0.750 (p < 0.001). There was a male predominance, with a 1.2:1 sex ratio. The median time from onset to diagnosis was 17.6 months, and the most common phenotypic presentations were spinal-onset and bulbar-onset ALS (62.7% and 14.7%, respectively). In total, 12.9% of the patients had familial ALS, likely due to the overrepresentation of ALS type 8 patients in our population. Conclusions: In general, our numbers are consistent with most international series and with those of other Brazilian cohorts. When patients were analyzed according to their MHDI a considerable delay in symptom onset was found, suggesting the possibility of an environmental effect on these patients. Brazil has a longer diagnostic delay which is similar to other less-developed countries. This is a substantial concern and should be a priority for health authorities and neurology societies.

Advancing Stem Cell Therapy for Repair of Damaged Lung Microvasculature in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal disease of motor neuron degeneration in the brain and spinal cord. Progressive paralysis of the diaphragm and other respiratory muscles leading to respiratory dysfunction and failure is the most common cause of death in ALS patients. Respiratory impairment has also been shown in animal models of ALS. Vascular pathology is another recently recognized hallmark of ALS pathogenesis. Central nervous system (CNS) capillary damage is a shared disease element in ALS rodent models and ALS patients. Microvascular impairment outside of the CNS, such as in the lungs, may occur in ALS, triggering lung damage and affecting breathing function. Stem cell therapy is a promising treatment for ALS. However, this therapeutic strategy has primarily targeted rescue of degenerated motor neurons. We showed functional benefits from intravenous delivery of human bone marrow (hBM) stem cells on restoration of capillary integrity in the CNS of an superoxide dismutase 1 (SOD1) mouse model of ALS. Due to the widespread distribution of transplanted cells via this route, administered cells may enter the lungs and effectively restore microvasculature in this respiratory organ. Here, we provided preliminary evidence of the potential role of microvasculature dysfunction in prompting lung damage and treatment approaches for repair of respiratory function in ALS. Our initial studies showed proof-of-principle that microvascular damage in ALS mice results in lung petechiae at the late stage of disease and that systemic transplantation of mainly hBM-derived endothelial progenitor cells shows potential to promote lung restoration via re-established vascular integrity. Our new understanding of previously underexplored lung competence in this disease may facilitate therapy targeting restoration of respiratory function in ALS.

Presentation of motor neuron disease in a patient with weight loss and acute-on-chronic respiratory failure

A previously fit and well 72-year-old man was referred to the acute medical unit with acute shortness of breath and confusion. He had presented 6 months earlier to his General Practitioner with a 6-month history of weight loss and lethargy. Despite CT imaging and extensive blood tests, no cause was found. He was having ongoing outpatient investigations, including a respiratory review leading up to his admission; the deterioration in his condition also coincided with the implementation of the COVID-19 lockdown. On admission, he was found to be in acute-on-chronic type 2 respiratory failure; examination revealed scattered fasciculations. Further inpatient electromyography (EMG) and nerve conduction study (NCS) confirmed motor neuron disease (MND). This case highlighted the importance of considering neuromuscular causes for acute respiratory failure in acute presentations and demonstrated the challenges in the diagnosis of MND in those presenting atypically with non-specific symptoms and the limitations of remote consultations in complex cases.

Clinical Course of Amyotrophic Lateral Sclerosis according to Initial Symptoms: An Analysis of 500 Cases

PURPOSE

One obstacle in early diagnosis of amyotrophic lateral sclerosis (ALS) is its vague initial presentation, which is generally classified into limb- and bulbar-dominant types and may be mistaken for other musculoskeletal conditions. We analyzed clinical data from patients in relation to their initial presentation and prognosis from symptom onset to diagnosis.

MATERIALS AND METHODS

We retrospectively analyzed the medical records of patients with ALS who were admitted for pulmonary rehabilitation between January 2007 and December 2019. We collected data on time of onset, initial presenting symptoms, unnecessary operations due to misdiagnosis, and the time between symptom onset and final diagnosis of ALS.

RESULTS

Among 500 patients, unnecessary operations were performed in 43 patients. The median durations between symptom onset and ALS diagnosis for patients with and without operations were 11 and 9 months, respectively (p=0.008). 67.0%, 28.8%, and 4.2% of the patients presented with limb-, bulbar-, and respiratory-dominant symptoms, respectively, as initial presentations. The median ages at symptom onset were significantly different for limb-, bulbar-, and respiratory-dominant onset (57.5, 60.6, and 66.7 years, respectively; p<0.001). Compared to the other two types, patients with the respiratory-dominant onset were all male and showed higher rate of emergent endotracheal intubation before ALS diagnosis.

CONCLUSION

Inappropriate operations significantly delayed the diagnosis of ALS. Respiratory difficulty can account for a significant proportion among initial presentations in ALS. Compared to limb- and bulbar-dominant types, respiratory-dominant onset appears to show male predominance, older age at symptom onset, and poor respiratory prognosis.

Brain Stimulation as a Therapeutic Tool in Amyotrophic Lateral Sclerosis: Current Status and Interaction With Mechanisms of Altered Cortical Excitability

In the last 20 years, several modalities of neuromodulation, mainly based on non-invasive brain stimulation (NIBS) techniques, have been tested as a non-pharmacological therapeutic approach to slow disease progression in amyotrophic lateral sclerosis (ALS). In both sporadic and familial ALS cases, neurophysiological studies point to motor cortical hyperexcitability as a possible priming factor in neurodegeneration, likely related to dysfunction of both excitatory and inhibitory mechanisms. A trans-synaptic anterograde mechanism of excitotoxicity is thus postulated, causing upper and lower motor neuron degeneration. Specifically, motor neuron hyperexcitability and hyperactivity are attributed to intrinsic cell abnormalities related to altered ion homeostasis and to impaired glutamate and gamma aminobutyric acid gamma-aminobutyric acid (GABA) signaling. Several neuropathological mechanisms support excitatory and synaptic dysfunction in ALS; additionally, hyperexcitability seems to drive DNA-binding protein 43-kDA (TDP-43) pathology, through the upregulation of unusual isoforms directly contributing to ASL pathophysiology. Corticospinal excitability can be suppressed or enhanced using NIBS techniques, namely, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), as well as invasive brain and spinal stimulation. Experimental evidence supports the hypothesis that the after-effects of NIBS are mediated by long-term potentiation (LTP)-/long-term depression (LTD)-like mechanisms of modulation of synaptic activity, with different biological and physiological mechanisms underlying the effects of tDCS and rTMS and, possibly, of different rTMS protocols. This potential has led to several small trials testing different stimulation interventions to antagonize excitotoxicity in ALS. Overall, these studies suggest a possible efficacy of neuromodulation in determining a slight reduction of disease progression, related to the type, duration, and frequency of treatment, but current evidence remains preliminary. Main limitations are the small number and heterogeneity of recruited patients, the limited "dosage" of brain stimulation that can be delivered in the hospital setting, the lack of a sufficient knowledge on the excitatory and inhibitory mechanisms targeted by specific stimulation interventions, and the persistent uncertainty on the key pathophysiological processes leading to motor neuron loss. The present review article provides an update on the state of the art of neuromodulation in ALS and a critical appraisal of the rationale for the application/optimization of brain stimulation interventions, in the light of their interaction with ALS pathophysiological mechanisms.

Humoral Influence of Repeated Lineage-Negative Stem/Progenitor Cell Administration on Articulatory Functions in ALS Patients

Amyotrophic lateral sclerosis (ALS) remains a fatal, neurodegenerative disease frequently leading to dysarthria and impaired swallowing. Better understanding of ALS pathophysiology is prompting the use of humoral cell therapies. Hence, a repeated cellular therapy was applied to ALS patients as an attempt to prevent speech deterioration. Autologous bone marrow-derived lineage-negative (Lin⁻) cells were intrathecally administered three times at six-week intervals to 42 sporadic ALS patients. Patients were examined for articulatory functions using subjective (VHI) and objective (FDA) scales. Selected trophic, proinflammatory factors and expression profiles of miRNA were measured in cerebrospinal fluid (CSF) and plasma by multiplex Luminex and q-PCR in different timepoints. Of the 42 patients who received the Lin⁻ cells, 6 showed improvement in articulatory functions, 27 remained stable, and 9 deteriorated after 18 weeks of therapy according to FDA scale. Clinical improvement was particularly evident by the 7^th day of each cell application and concerned better cough and swallow reflex, soft palate, laryngeal time, pitch, and volume. These results correlated with significant changes in the concentration of various trophic and proinflammatory factors and miRNA expression profiles. A multiple application of Lin⁻ cells proved to be safe and feasible. The repeated procedure can potentate a humoral effect and prevent speech deterioration. A short-lasting trophic effect of each Lin⁻ cells administration was observed on local and systemic level. However, further in-depth studies are necessary to sustain the beneficial effect.

Diaphragm ultrasound in the diagnosis of respiratory dysfunction in patients with amyotrophic lateral sclerosis

OBJECTIVE

In this study, we aimed to select the best diaphragm ultrasonography (DUS) parameter as an alternative index for the diagnosis of lung function impairment in amyotrophic lateral sclerosis (ALS).

METHODS

Twenty-nine patients with ALS and 15 healthy subjects were enrolled in the study. DUS, lung function tests, phrenic nerve conduction study and arterial blood gas analysis were performed.

RESULTS

Patients with respiratory dysfunction had a significantly lower level of ΔTmax than those without (P=0.039). Significant correlations (P<0.05) were found between forced vital capacity (FVC) and Tdi-ins (r=0.665, P<0.0001) and ΔTmax (r=-0.748, P<0.0001) and Δins-exp (r=0.627, P<0.0001) and ΔTdi (r=0.485, P<0.0001). Receiver Operating Curves analysis demonstrated that ΔTmax (AUC=0.76, P=0.044) had a better overall accuracy for detection of respiratory dysfunction compared with Tdi-ins (AUC=0.27, P=0.067), Δins-exp (AUC=0.312, P=0.139), and ΔTdi (AUC=0.38, P=0.359).

CONCLUSION

ΔTmax is the most valuable DUS index in the diagnosis of diaphragmatic dysfunction.

SIGNIFICANCE

DUS can provide functional and structural information of diaphragm and help to diagnose diaphragmatic dysfunction in ALS.

Home invasive mechanical ventilation in Finland in 2015-2019

INTRODUCTION

The prevalence of long-term invasive mechanical ventilation via tracheostomy in chronic respiratory insufficiency is largely unknown. We aimed to clarify prevalence and aetiology of the use of home invasive mechanical ventilation (HIMV) in Finland in 2015-2019.

METHODS

Information on HIMV patients was collected yearly from all Finnish Hospital District patient registries between 1 January 2015 and 1 January 2019. Data included underlying diagnosis, time from diagnosis to HIMV initiation, treatment length, mortality and basic sociodemographic data.

RESULTS

In 2015, we had 107 HIMV patients. During the follow-up we received 34 new patients (24.1%) and 46 patients (32.6%) died. In 2019, we had 95 HIMV patients and the prevalence in Finland was 2.0 in 100 000. The most common diagnoses were motor neurone disease (29.1%) and spinal cord injuries (19.9%). Mean duration of HIMV among all patients on 1 January 2019 was 12.3 years and among deceased patients, 11.2 years. Treatment durations ranged from 7.7 years for motor neurone disease patients to 47.3 years for post-polio syndrome patients. Most patients (81.6%) used HIMV 24 h·day-1.

CONCLUSIONS

HIMV is a rare, long-lasting treatment, most often used in chronic hypoventilation caused by chronic neurological disease. Based on our 4 year follow-up the prevalence of HIMV seems to be diminishing in Finland. Treatment duration and survival vary greatly depending on the underlying diagnosis. Most of the patients were totally dependent on HIMV, requiring 24-h care.

The Relationship between Selected Demographic Factors and Speech Organ Dysfunction in Sporadic ALS Patients

Background and objectives: Speech disorders are observed in 30% of newly diagnosed sporadic amyotrophic lateral sclerosis (ALS) patients. Characterized by a dynamic course, dysfunction of articulation has not so far been well understood. The aim of this study was to analyze the influence of demographic factors (sex, age, duration of the disease) and concomitant diseases (degenerative spine disease, depression, hypertension, hypothyroidism, hyperthyroidism, and allergy) on the functioning of speech organs in ALS patients. Materials and Methods: The study group consisted of 65 patients with sporadic ALS. Patients were examined for articulatory functions by means of the Frenchay Dysarthria Assessment (FDA). Results: 68% of the study sample had spinal disorders. Logistic regression analysis showed that a decline in the functioning of lips, soft palate, length of phonation, and voice loudness was more common among men. Patients diagnosed with degenerative spine disease more often suffered from respiratory disorders, while younger patients (<60 years of age) significantly more often had the impairment of the sentence and spontaneous speech functions. Conclusions: The male gender in patients with ALS is associated with an increased risk of deterioration of the phonation length function. Patients under 60 years of age are associated with more often pronouncing sentences disorders and spontaneous speech disorders.

Potential of the Cardiovascular Drug Levosimendan in the Management of Amyotrophic Lateral Sclerosis: An Overview of a Working Hypothesis

Levosimendan is a calcium sensitizer that promotes myocyte contractility through its calcium-dependent interaction with cardiac troponin C. Administered intravenously, it has been used for nearly 2 decades to treat acute and advanced heart failure and to support the heart function in various therapy settings characterized by low cardiac output. Effects of levosimendan on noncardiac muscle suggest a possible new application in the treatment of people with amyotrophic lateral sclerosis (ALS), a neuromuscular disorder characterized by progressive weakness, and eventual paralysis. Previous attempts to improve the muscle response in ALS patients and thereby maintain respiratory function and delay progression of disability have produced some mixed results. Continuing this line of investigation, levosimendan has been shown to enhance in vitro the contractility of the diaphragm muscle fibers of non-ALS patients and to improve in vivo diaphragm neuromuscular efficiency in healthy subjects. Possible positive effects on respiratory function in people with ALS were seen in an exploratory phase 2 study, and a phase 3 clinical trial is now underway to evaluate the potential benefit of an oral form of levosimendan on both respiratory and overall functions in patients with ALS. Here, we will review the various known pharmacologic effects of levosimendan, considering their relevance to people living with ALS.

Multifaceted Genes in Amyotrophic Lateral Sclerosis-Frontotemporal Dementia

Amyotrophic lateral sclerosis and frontotemporal dementia are two progressive, adult onset neurodegenerative diseases, caused by the cell death of motor neurons in the motor cortex and spinal cord and cortical neurons in the frontal and temporal lobes, respectively. Whilst these have previously appeared to be quite distinct disorders, in terms of areas affected and clinical symptoms, identification of cognitive dysfunction as a component of amyotrophic lateral sclerosis (ALS), with some patients presenting with both ALS and FTD, overlapping features of neuropathology and the ongoing discoveries that a significant proportion of the genes underlying the familial forms of the disease are the same, has led to ALS and FTD being described as a disease spectrum. Many of these genes encode proteins in common biological pathways including RNA processing, autophagy, ubiquitin proteasome system, unfolded protein response and intracellular trafficking. This article provides an overview of the ALS-FTD genes before summarizing other known ALS and FTD causing genes where mutations have been found primarily in patients of one disease and rarely in the other. In discussing these genes, the review highlights the similarity of biological pathways in which the encoded proteins function and the interactions that occur between these proteins, whilst recognizing the distinctions of MAPT-related FTD and SOD1-related ALS. However, mutations in all of these genes result in similar pathology including protein aggregation and neuroinflammation, highlighting that multiple different mechanisms lead to common downstream effects and neuronal loss. Next generation sequencing has had a significant impact on the identification of genes associated with both diseases, and has also highlighted the widening clinical phenotypes associated with variants in these ALS and FTD genes. It is hoped that the large sequencing initiatives currently underway in ALS and FTD will begin to uncover why different diseases are associated with mutations within a single gene, especially as a personalized medicine approach to therapy, based on a patient's genetics, approaches the clinic.

Prognosis of amyotrophic lateral sclerosis patients undergoing tracheostomy invasive ventilation therapy in Japan

OBJECTIVE

The aim of this study is to describe and clarify the factors affecting the prognosis of Japanese patients with amyotrophic lateral sclerosis (ALS) undergoing tracheostomy invasive ventilation (TIV) therapy.

METHODS

We conducted a prospective longitudinal observational case-control study using a multicentre registry. ALS patients who started TIV therapy after registration (TIV group) and those who did not receive TIV (non-TIV group) were included. We compared the survival time between the TIV group and the non-TIV group using a propensity score matching analysis and evaluated the prognostic factors in the TIV group.

RESULTS

From February 2006 to January 2018, 190 patients in the TIV group and 1093 patients in the non-TIV group were included in this study. The mean age of disease onset and usage rate of gastrostomy and non-invasive ventilation therapy differed between the groups. In the propensity score matching analysis using known prognostic factors, the median overall survival time of the TIV group was significantly greater than that of the non-TIV group (11.33 years vs 4.61 years; p<0.001). Analysis using the Cox proportional hazard model suggested that older age of onset and respiratory onset was an independent factor for poor prognosis after starting TIV therapy.

CONCLUSION

We showed that there was a significant difference of approximately 7 years in life expectancy between Japanese ALS patients who did and did not receive TIV therapy.

Sleep disturbances in patients with amyotrophic lateral sclerosis: current perspectives

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease inevitably leading to generalized muscle weakness and premature death. Sleep disturbances are extremely common in patients with ALS and substantially add to the burden of disease for both patients and caregivers. Disruption of sleep can be caused by physical symptoms, such as muscle cramps, pain, reduced mobility, spasticity, mucus retention, and restless legs syndrome. In addition, depression and anxiety may lead to significant insomnia. In a small subset of patients, rapid eye movement (REM) sleep behavioral disorder may be present, reflecting neurodegeneration of central nervous system pathways which are involved in REM sleep regulation. With regard to overall prognosis, sleep-disordered breathing (SDB) and nocturnal hypoventilation (NH) are of utmost importance, particularly because NH precedes respiratory failure. Timely mechanical ventilation is one of the most significant therapeutic measures to prolong life span in ALS, and transcutaneous capnometry is superior to pulse oxymetry to detect NH early. In addition, it has been shown that in patients on home ventilatory support, survival time depends on whether normocapnia, normoxia, and elimination of apneic events during sleep can be reliably achieved. Several studies have investigated sleep patterns and clinical determinants of sleep disruption in ALS, but exact prevalence numbers are unknown. Thus, constant awareness for sleep-related symptoms is appropriate. Since no curative treatment can be offered to affected patients, sleep complaints should be thoroughly investigated in order to identify any treatable etiology and improve or stabilize quality of life as much as possible. The use of hypnotics should be confined to palliation during the terminal phase and refractory insomnia in earlier stages of the disease, taking into account that most compounds potentially aggravate SDB.

Tollgate-based progression pathways of ALS patients

OBJECTIVE

To capture ALS progression in arm, leg, speech, swallowing, and breathing segments using a disease-specific staging system, namely tollgate-based ALS staging system (TASS), where tollgates refer to a set of critical clinical events including having slight weakness in arms, needing a wheelchair, needing a feeding tube, etc. METHODS: We compiled a longitudinal dataset from medical records including free-text clinical notes of 514 ALS patients from Mayo Clinic, Rochester-MN. We derived tollgate-based progression pathways of patients up to a 1-year period starting from the first clinic visit. We conducted Kaplan-Meier analyses to estimate the probability of passing each tollgate over time for each functional segment.

RESULTS

At their first clinic visit, 93%, 77%, and 60% of patients displayed some level of limb, bulbar, and breathing weakness, respectively. The proportion of patients at milder tollgate levels (tollgate level < 2) was smaller for arm and leg segments (38% and 46%, respectively) compared to others (> 65%). Patients showed non-uniform TASS pathways, i.e., the likelihood of passing a tollgate differed based on the affected segments at the initial visit. For instance, stratified by impaired segments at the initial visit, patients with limb and breathing impairment were more likely (62%) to use bi-level positive airway pressure device in a year compared to those with bulbar and breathing impairment (26%).

CONCLUSION

Using TASS, clinicians can inform ALS patients about their individualized likelihood of having critical disabilities and assistive-device needs (e.g., being dependent on wheelchair/ventilation, needing walker/wheelchair or communication devices), and help them better prepare for future.

Respiratory measures in amyotrophic lateral sclerosis

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease that causes skeletal muscle weakness, including muscles involved with respiration. Death often results from respiratory failure within 3-5 years. Monitoring respiratory status is therefore critical to ALS management, as respiratory/pulmonary function tests (PFTs) are used to make decisions including when to initiate noninvasive ventilation. Understanding the different respiratory and PFTs as they relate to disease progression and survival may help determine which tests are most suitable.

METHODS

This review describes the tests used to assess respiratory muscle and pulmonary function in patients with ALS and the correlations between different respiratory measures and clinical outcomes measures.

RESULTS

The most commonly used measurement, forced vital capacity (VC), has been shown to correlate with clinical milestones including survival, but also requires good motor coordination and facial strength to form a tight seal around a mouthpiece. Other tests such as slow VC, sniff inspiratory pressure, or transdiaphragmatic pressure with magnetic stimulation are also associated with distinct advantages and disadvantages.

CONCLUSIONS

Therefore, how and when to use different tests remains unclear. Understanding how each test relates to disease progression and survival may help determine which is best suited for specific clinical decisions.

Impact of an early respiratory care programme with non-invasive ventilation adaptation in patients with amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Forced vital capacity (FVC) <80% is one of the key indications for starting non-invasive ventilation (NIV) in amyotrophic lateral sclerosis (ALS). It was hypothesized that a very early start of NIV could lengthen the free interval before death compared to later-start NIV; as a secondary outcome, the survival rate of patients on NIV without tracheotomy was also evaluated.

METHODS

This retrospective study was conducted on 194 ALS patients, divided into a later group (LG) with FVC <80% at NIV prescription (n = 129) and a very early group (VEG) with FVC ≥80% at NIV prescription (n = 65). Clinical and respiratory functional data and time free to death between groups over a 3-year follow-up were compared.

RESULT

At 36 months from diagnosis, mortality was 35% for the VEG versus 52.7% for the LG (P = 0.022). Kaplan-Meier survival curves adjusted for tracheotomy showed a lower probability of death (P = 0.001) for the VEG as a whole (P = 0.001) and for the non-bulbar (NB) subgroup (P = 0.007). Very early NIV was protective of survival for all patients [hazard ratio (HR) 0.45; 95% confidence interval (CI) 0.28-0.74; P = 0.001] and for the NB subgroup (HR 0.43; 95% CI 0.23-0.79; P = 0.007), whilst a tracheotomy was protective for all patients (HR 0.27; 95% CI 0.15-0.50; P = 0.000) and both NB (HR 0.26; 95% CI 0.12-0.56; P = 0.001) and bulbar subgroups (HR 0.29; 95% CI 0.11-0.77; P = 0.013). Survival in VEG patients on NIV without tracheotomy was three times that for the LG (43.1% vs. 14.7%).

CONCLUSION

Very early NIV prescription prolongs the free time from diagnosis to death in NB ALS patients whilst tracheotomy reduces the mortality risk in all patients.

Head-drop: A frequent feature of late-onset myasthenia gravis

INTRODUCTION

Head-drop is often encountered in myasthenia gravis (MG) patients, but its frequency and clinical course have not been studied systematically.

METHODS

In a retrospective study of a cohort of MG patients seen over a period of 11 years in a tertiary medical center, we assessed the clinical characteristics of patients who had head-drop.

RESULTS

Of 146 generalized MG patients, 15 had head-drop during the course of their disease. Head-drop patients had older age of onset than those who did not have head-drop (mean age of onset 59.1 vs. 42.3 years) and were predominantly men. Head-drop was present in 23% of patients > 60 versus 6% of those < 60 years, and it improved in 9 of 11 patients with treatment directed to generalized MG.

CONCLUSIONS

Head-drop is a common, treatment-responsive manifestation of late-onset MG. Muscle Nerve 56: 441-444, 2017.

Age-Related Uptake of Heavy Metals in Human Spinal Interneurons

Toxic heavy metals have been implicated in the loss of spinal motoneurons in amyotrophic lateral sclerosis/motor neuron disease (ALS/MND). Motoneuron loss in the spinal anterior horn is severe in ALS/MND at the time of death, making this tissue unsuitable for examination. We therefore examined spinal cords of people without muscle weakness to look for any presence of heavy metals that could make these neurons susceptible to damage. Spinal cord samples from 50 individuals aged 1–95 y who had no clinical or histopathological evidence of spinal motoneuron loss were studied. Seven μm formalin-fixed paraffin-embedded sections were stained for heavy metals with silver nitrate autometallography (AMG^HM) which detects intracellular mercury, silver or bismuth. Neurons in the spinal cord were classified as interneurons or α-motoneurons based on their site and cell body diameter. Spinal interneurons containing heavy metals were present in 8 of 24 people (33%) aged 61–95 y, but not at younger ages. These AMG^HM interneurons were most numerous in the lumbar spinal cord, with moderate numbers in the caudal cervical cord, few in the rostral cervical cord, and almost none in the thoracic cord. All people with AMG^HM interneurons had occasional AMG^HM staining in α-motoneurons as well. In one man AMG^HM staining was present in addition in dorsomedial nucleus and sensory neurons. In conclusion, heavy metals are present in many spinal interneurons, and in a few α-motoneurons, in a large proportion of older people. Damage to inhibitory interneurons from toxic metals in later life could result in excitotoxic injury to motoneurons and may underlie motoneuron injury or loss in conditions such as ALS/MND, multiple sclerosis, sarcopenia and calf fasciculations.

Pathophysiological Concepts and Treatment of Camptocormia

Camptocormia is a disabling pathological, non-fixed, forward bending of the trunk. The clinical definition using only the bending angle is insufficient; it should include the subjectively perceived inability to stand upright, occurrence of back pain, typical individual complaints, and need for walking aids and compensatory signs (e.g. back-swept wing sign). Due to the heterogeneous etiologies of camptocormia a broad diagnostic approach is necessary. Camptocormia is most frequently encountered in movement disorders (PD and dystonia) and muscles diseases (myositis and myopathy, mainly facio-scapulo-humeral muscular dystrophy (FSHD)). The main diagnostic aim is to discover the etiology by looking for signs of the underlying disease in the neurological examination, EMG, muscle MRI and possibly biopsy. PD and probably myositic camptocormia can be divided into an acute and a chronic stage according to the duration of camptocormia and the findings in the short time inversion recovery (STIR) and T1 sequences of paravertebral muscle MRI. There is no established treatment of camptocormia resulting from any etiology. Case series suggest that deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) is effective in the acute but not the chronic stage of PD camptocormia. In chronic stages with degenerated muscles, treatment options are limited to orthoses, walking aids, physiotherapy and pain therapy. In acute myositic camptocormia an escalation strategy with different immunosuppressive drugs is recommended. In dystonic camptocormia, as in dystonia in general, case reports have shown botulinum toxin and DBS of the globus pallidus internus (GPi-DBS) to be effective. Camptocormia in connection with primary myopathies should be treated according to the underlying illness.

[Epidemiology, clinical spectrum of ALS and differential diagnoses]

Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease in adults. Its incidence in France is estimated at 2.5 per 100,000 population and its prevalence between 5 and 8 per 100,000 inhabitants. Good prognostic factors are age of early onset, a longer time to diagnosis, initial damage to the spinal onset, early management of undernutrition and restrictive respiratory failure. The diagnosis of ALS is primarily clinical and is based on the evidence of involvement of the central motor neuron and peripheral neuron (NMP) in different territories or spinal or bulbar. The EMG confirms the achievement of NMP, shows the extension to clinically preserved areas and allows to exclude some differential diagnoses. The clinical spectrum of ALS is broad: conventional forms beginning brachial, lower limb or bulbar onsets, rarer forms to start breathing, pyramidal forms, forms with cognitive and behavioural impairment. In 5-10% of cases, ALS is familial. In 15% of cases, it is associated with frontotemporal degeneration rather than orbito-frontal type. The main differential diagnoses are guided by the clinic: combining pure motor neuropathy with or without conduction block, post-polio syndrome, cramp-fasciculation syndrome, myasthenia gravis, paraneoplastic syndromes, Sjögren syndrome, retroviral infections, some endocrine disorders, some metabolic diseases, genetic diseases (Kennedy and SMA) and inclusion body myositis.

Ventilatory control in ALS

Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease. ALS selectively causes degeneration in upper and lower (spinal) motor neurons, leading to muscle weakness, paralysis and death by ventilatory failure. Although ventilatory failure is generally the cause of death in ALS, little is known concerning the impact of this disorder on respiratory motor neurons, the consequences of respiratory motor neuron cell death, or the ability of the respiratory control system to "fight back" via mechanisms of compensatory respiratory plasticity. Here we review known effects of ALS on breathing, including possible effects on rhythm generation, respiratory motor neurons, and their target organs: the respiratory muscles. We consider evidence for spontaneous compensatory plasticity, preserving breathing well into disease progression despite dramatic loss of spinal respiratory motor neurons. Finally, we review current and potential therapeutic approaches directed toward preserving the capacity to breathe in ALS patients.

Amyotrophic lateral sclerosis and the clinical potential of dexpramipexole

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that leads to progressive weakness from loss of motor neurons and death on average in less than 3 years after symptom onset. No clear causes have been found and just one medication, riluzole, extends survival. Researchers have identified some of the cellular processes that occur after disease onset, including mitochondrial dysfunction, protein aggregation, oxidative stress, excitotoxicity, inflammation, and apoptosis. Mitochondrial disease may be a primary event in neurodegeneration or occur secondary to other cellular processes, and may itself contribute to oxidative stress, excitotoxicity, and apoptosis. Clinical trials currently aim to slow disease progression by testing drugs that impact one or more of these pathways. While every agent tested in the 18 years after the approval of riluzole has been ineffective, basic and clinical research methods in ALS have become dramatically more sophisticated. Dexpramipexole (RPPX), the R(+) enantiomer of pramiprexole, which is approved for symptomatic treatment of Parkinson disease, carries perhaps the currently largest body of pre-and early clinical data that support testing in ALS. The neuroprotective properties of RPPX in various models of neurodegeneration, including the ALS murine model, may be produced through protective actions on mitochondria. Early phase trials in human ALS suggest that the drug can be taken safely by patients in doses that provide neuroprotection in preclinical models. A Phase III trial to test the efficacy of RPPX in ALS is underway.

Limitations of sniff nasal pressure as an outcome measurement in amyotrophic lateral sclerosis patients in a clinical trial

BACKGROUND

The forced vital capacity (FVC) is an established measure in amyotrophic lateral sclerosis (ALS) clinical trials. Recently the sniff nasal inspiratory pressure (SNIP) test has been increasingly used as a respiratory measure.

OBJECTIVES

It was the aim of this study to assess the feasibility of SNIP as an outcome measure in a phase III clinical trial with a lead-in design.

METHODS

Twenty patients were enrolled in a randomized clinical trial. FVC, SNIP in sitting (SNIPsitt) and supine (SNIPsup) positions, and the ALS functional rating scale score (ALSFRS-R) were measured every 4 weeks.

RESULTS

Complete data were available for 19 patients over 5 months. Baseline values were normal for FVC (101 ± 14%) but abnormal for SNIPsitt and SNIPsup (84 ± 34% and 82 ± 33%). While FVC and ALSFRS-R declined in parallel, SNIPsitt measures declined significantly less compared to ALSFRS-R (p < 0.05) and FVC (p < 0.001) up to 4 months after enrollment. Over 50% of patients still had values equal to or above baseline SNIPsitt measures after 3 months despite abnormal baseline values.

CONCLUSIONS

The delayed decline in SNIP measurements suggests a learning effect over time. The optimal number of SNIPs in ALS clinical trials has yet to be determined. SNIP measures should be used with caution in trials with a lead-in design.