Long-term survival in Werdnig-Hoffmann disease

Sleep and sleep-related breathing disorders in patients with spinal muscular atrophy: a changing perspective from novel treatments?

Spinal Muscular Atrophy (SMA) is an inherited neuromuscular disorder characterized by progressive muscle weakness and atrophy, resulting from the degeneration of motor neurons in the spinal cord. A critical aspect of SMA is its impact on respiratory function. As the disease progresses, respiratory muscles, in particular intercostal muscles, become increasingly affected, leading to breathing difficulties and respiratory failure. Without intervention, many children with SMA type 1 die from respiratory failure before their second year of life. While assisted ventilation has improved survival, it often results in ventilator dependence. The development of new SMN-augmenting therapies has renewed optimism, but their long-term impact on respiratory function is uncertain, and non-invasive respiratory support remains an important part of SMA management. Despite the importance of respiratory support in SMA, knowledge regarding sleep disorders in this population is limited. This review aims to synthesize existing literature on sleep and sleep-related breathing disorders in patients with SMA, with a focus on SMA type 1. We summarize evidence of sleep-disordered breathing and respiratory failure in SMA, as well as outcomes and survival benefits associated with non-invasive or invasive ventilation with or without pharmacological therapies. We also discuss current knowledge regarding the effects of novel disease-modifying therapies for SMA on respiratory function and sleep. In conclusion, optimal care for children with SMA requires a multidisciplinary approach that includes neurology and respiratory specialists. This review highlights the importance of monitoring sleep and respiratory function in SMA, as well as the potential benefits and challenges associated with assisted ventilation combined with new therapies.

Patients with Spinal Muscular Atrophy Type 1 Achieve and Maintain Bulbar Function Following Onasemnogene Abeparvovec Treatment

BACKGROUND

Improvement and maintenance of bulbar function are goals of disease-modifying treatments for spinal muscular atrophy (SMA). Lack of standardized measures and a widely accepted definition of bulbar function represents a gap in SMA care.

OBJECTIVE

A multidisciplinary team conducted post-hoc analyses of pooled data from one phase 1 (START) and two phase 3 (STR1VE-US, STR1VE-EU) studies to define and evaluate bulbar function of infants with SMA type 1 after receiving one-time gene replacement therapy, onasemnogene abeparvovec.

METHODS

We defined bulbar function as the ability to meet nutritional needs while maintaining airway protection and the ability to communicate verbally. Four endpoints represented adequate bulbar function: (1) absence of clinician-identified physiologic swallowing impairment, (2) receiving full oral nutrition, (3) absence of adverse events indicating pulmonary instability, and (4) the ability to vocalize at least two different, distinct vowel sounds. We descriptively assessed numbers/percentages of patients who achieved each endpoint and all four collectively. Patients were followed until 18 months old (STR1VE-US and STR1VE-EU) or 24 months (START) post-infusion.

RESULTS

Overall, 65 patients were analyzed for swallowing, nutrition intake, and adverse events, and 20 were analyzed for communication. At study end, 92% (60/65) of patients had a normal swallow, 75% (49/65) achieved full oral nutrition, 92% (60/65) had no evidence of pulmonary instability, 95% (19/20) met the communication endpoint, and 75% (15/20) achieved all four bulbar function components in the composite endpoint.

CONCLUSIONS

In these three clinical trials, patients with SMA type 1 who received onasemnogene abeparvovec achieved and maintained the bulbar function criteria utilized within this investigation.

Exploratory evaluation of an eye-tracking system in patients with advanced spinal muscular atrophy type I receiving nusinersen

Objective

This study evaluated the feasibility of a matching-pair test using eye-tracking technology to assess nusinersen effectiveness in patients with advanced spinal muscular atrophy (SMA) type I.

Methods

This prospective, observational study enrolled patients with 5q-SMA type I who had lost gross motor function. Three different levels of matching-pair tests were conducted using the eye-gaze system (My Tobii; TobiiDynavox Inc.) at baseline, and after 9 and 24 weeks of nusinersen treatment. The primary endpoint was the change from baseline in matching-pair test scores and response times (i.e., the time to answer matching-pair test) at 24 weeks from baseline. Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), Pediatric Quality of Life inventory for patients with Neuromuscular Disease (PedsQL-NM) and Numerical Rating Scale (NRS) scores were also assessed as secondary endpoints. Analysis of ocular fixation was performed as an additional analysis. This study was registered at https://www.umin.ac.jp/ctr/ (UMIN000033935).

Results

Seven patients (one male, six female) aged 5–21 years (median 11 years) were enrolled; all patients were bedridden and six patients were ventilated. All seven patients were able to conduct level 1 matching-pair tests at each assessment; five patients were also able to conduct levels 2 and 3. Two patients (those with the highest CHOP-INTEND scores) were able to complete all tests correctly within 60 s. There was a non-significant trend toward improvement in CHOP-INTEND, PedsQL-NM, and NRS scores over the 6-month period. There were no significant differences in the number of actions, errors, correct answers, or response times between baseline and Week 9 or 24 at any level. However, the result of an additional analysis suggests that detection of eye movement would be useful to evaluate for advanced SMA.

Conclusions

Eye-tracking systems are possibly feasible for the assessment of treatment efficacy in patients with advanced SMA type I.

ERS Statement on pediatric long term noninvasive respiratory support

Long term noninvasive respiratory support, comprising continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV), in children is expanding worldwide, with increasing complexities of children being considered for this type of ventilator support and expanding indications such as palliative care. There have been improvements in equipment and interfaces. Despite growing experience, there are still gaps in a significant number of areas: there is a lack of validated criteria for CPAP/NIV initiation, optimal follow-up and monitoring; weaning and long term benefits have not been evaluated. Therapeutic education of the caregivers and the patient is of paramount importance, as well as continuous support and assistance, in order to achieve optimal adherence. The preservation or improvement of the quality of life of the patient and caregivers should be a concern for all children treated with long term CPAP/NIV. As NIV is a highly specialised treatment, patients are usually managed by an experienced pediatric multidisciplinary team. This Statement written by experts in the field of pediatric long term CPAP/NIV aims to emphasize on the most recent scientific input and should open up to new perspectives and research areas.

Continuous noninvasive ventilatory support outcomes for patients with neuromuscular disease: a multicenter data collaboration

BACKGROUND

Typically, patients with progressive neuromuscular disorders (NMDs) develop acute respiratory failure (ARF), are intubated, and when failing spontaneous breathing trials (SBTs) undergo a tracheotomy and receive tracheostomy mechanical ventilation (TMV). However, increasing numbers of patients use nasal noninvasive ventilation (NIV), initially for sleep and this is extended to continuous dependence (CNVS). This can be used as a strategy to assist in successful extubation . We retrospectively reviewed 19 centers offering CNVS and mechanical insufflation-exsufflation (MI-E) as an alternative to TMV.

METHODS

Centers with publications or presentations concerning CNVS outcomes data were pooled for amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy (DMD), and spinal muscular atrophy type 1 (SMA1). Progression to CNVS dependence without hospitalization, duration of dependence, and extubations and decannulations to CNVS were recorded. Prolongation of life was defined by duration of CNVS dependence without ventilator free breathing ability (VFBA).

RESULTS

There were 1623 part time (<23 h/day) NVS users with ALS, DMD, and SMA1 from 19 centers in 16 countries of whom 761 (47%) were CNVS dependent for 2218 patient-years. This included: 335 ALS patients for a mean 1.2 ± 1.0 (range to 8) years each; 385 DMD patients for 5.4 ± 1.6 (range to 29) years; and 41 SMA1 patients for 5.9 ± 1.8 (range to 20) years. Thirty-five DMD and ALS TMV users were decannulated to CNVS and MI-E. At data collection 494 (65%) patients were CNVS dependent but 110 (74 of whom with bulbar ALS), had undergone tracheotomies.

CONCLUSIONS

ALS, DMD, and SMA1 patients can become CNVS dependent without requiring hospitalization but CNVS cannot be used indefinitely for many patients with advanced upper motor neuron diseases.

Oral and Swallowing Abilities Tool (OrSAT) for Type 1 SMA Patients: Development of a New Module

We describe the development of a new tool specifically designed to record oral abilities, swallowing and, more generally, feeding in young type 1 SMA patients, to be used during the first 24 months of life.The tool is composed by a checklist and a separate section summarizing the functional abilities into levels of feeding/swallowing impairment. The checklist includes 12 questions assessing aspects thought to be clinically meaningful for a type 1 SMA population and developmentally appropriate for infants during the first months of life. Each item is graded with a score of 0 or 1, depending on the child's ability to perform the activity. As some items are age-dependent, the number of items to be used, and therefore the maximum score, changes with increasing age. The levels of feeding/swallowing impairment include four levels that can be identified using easily identifiable clinical criteria.In an attempt to validate the tool in an untreated population we applied it to 24 type 1 SMA patients (age range: 2.3-24.1 months, mean: 10.8) in whom the same information collected by the new tool had been previously recorded using a less-structured format.When patients were classified in three groups according to the Dubowitz decimal classification, there was a significant difference both at baseline and at follow-up (p < 0.001). The items assessing fatigue during the nursing sessions were the most frequently impaired even in infants who did not have any other obvious clinical sign of swallowing difficulties.

Outcomes of Long-term Non-invasive Ventilation Use in Children with Neuromuscular Disease: Systematic Review and Meta-analysis

OBJECTIVE

To determine whether children with neuromuscular disorders using long-term non-invasive ventilation, continuous or bilevel positive airway pressure, have improved health outcomes compared to alternative treatment strategies.

DATA SOURCES

This systematic review is an extension of a scoping review. The search strategy used Medical Subject Headings (MeSH) and free-text terms for "child" and "non-invasive ventilation." Studies of humans from 1990 onward were searched in MEDLINE (Ovid), Embase (Ovid), CINAHL (Ebsco), Cochrane Library (Wiley), and PubMed. The results were reviewed for articles reporting on neuromuscular disorders and health outcomes including mortality, hospitalization, quality of life, lung function, sleep study parameters, and healthcare costs.

DATA EXTRACTION

Extracted data included study design, study duration, sample size, age, type of non-invasive ventilation, follow-up period, primary disease, and primary and secondary outcome measures. Studies were grouped by primary disease into 3 groups: spinal muscular atrophy, Duchenne muscular dystrophy, and other/multiple neuromuscular diseases.

DATA SYNTHESIS

A total of 50 articles including 1412 children across 36 different neuromuscular disorders are included in the review. Mortality is lower for children using long-term non-invasive ventilation compared to supportive care across all neuromuscular disease types. Overall, mortality does not differ when comparing the use of non-invasive ventilation to invasive mechanical ventilation though heterogeneity suggests that mortality with non-invasive ventilation is higher for spinal muscular atropy type-1 and lower for other/multiple neuromuscular diseases. The impact of long-term non-invasive ventilation on hospitalization rate differed by neuromuscular disease type with lower rates compared to invasive mechanical ventilation but higher rates compared to invasive mechanical ventilation use for spinal muscular atrophy type 1, and lower rates compared to before NIV for other/multiple neuromuscular diseases. Overall, lung function was unaltered and sleep study parameters were improved from baseline by long-term non-invasive ventilation use. There are few data to assess the impact of long-term non-invasive ventilation use on quality of life and healthcare costs.

CONCLUSION

Long-term non-invasive ventilation for children provides benefit for mortality, hospitalizations, and sleep study parameters for some sub-groups of children with neuromuscular disorders. High risk of bias and low study quality preclude strong conclusions.

Intellectual abilities, language comprehension, speech, and motor function in children with spinal muscular atrophy type 1

Background

Spinal muscular atrophy (SMA) is a chronic, neuromuscular disease characterized by degeneration of spinal cord motor neurons, resulting in progressive muscular atrophy and weakness. SMA1 is the most severe form characterized by significant bulbar, respiratory, and motor dysfunction. SMA1 prevents children from speaking a clearly understandable and fluent language, with their communication being mainly characterized by eye movements, guttural sounds, and anarthria (type 1a); severe dysarthria (type 1b); and nasal voice and dyslalia (type 1c).

The aim of this study was to analyze for the first time cognitive functions, language comprehension, and speech in natural history SMA1 children according to age and subtypes, to develop cognitive and language benchmarks that provide outcomes for the clinical medication trials that are changing SMA1 course/trajectory.

Methods

This is a retrospective study including 22 children with SMA1 (10 affected by subtype 1a-1b: AB and 12 by 1c: C) aged 3–11 years in clinical stable condition with a coded way to communicate “yes” and “no”. Data from the following assessments have been retrieved from patient charts: one-dimensional Raven test (RCPM), to evaluate cognitive development (IQ); ALS Severity Score (ALSSS) to evaluate speech disturbances; Brown Bellugy modified for Italian standards (TCGB) to evaluate language comprehension; and Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) to assess motor functioning.

Results

SMA 1AB and 1C children were similar in age, with the former characterized by lower CHOP-INTEND scores compared to the latter. All 22 children had collaborated to RCPM and their median IQ was 120 with no difference (p = 0.945) between AB and C. Global median score of the speech domain of the ALSSS was 5; however, it was 2 in AB children, being significantly lower than C (6.5, p < 0.001).

TCGB test had been completed by 13 children, with morphosyntactic comprehension being in the normal range (50). Although ALSSS did not correlate with both IQ and TCGB, it had a strong (p < 0.001) correlation with CHOP-INTEND described by an exponential rise to maximum.

Conclusions

Although speech and motor function were severely compromised, children with SMA1 showed general intelligence and language comprehension in the normal range. Speech impairment was strictly related to global motor impairment.

Liberation and mortality outcomes in pediatric long-term ventilation: A qualitative systematic review

OBJECTIVE

To provide a systematic review of liberation from positive pressure ventilation and mortality of children with chronic respiratory failure who used long-term invasive and noninvasive ventilation (LTV).

METHODS

Papers published from 1980 to 2018 were identified using Pubmed MEDLINE, Ovid MEDLINE, Embase, and Cochrane databases. Search results were limited to English-language papers with (a) patients less than 22 years at initiation, (b) patients who used invasive ventilation (IV) via tracheostomy or noninvasive ventilation (NIV), and (c) data on mortality or liberation from LTV. Data were presented using descriptive statistics; changes in outcomes over time were explored using linear regression. Follow-up variability, cohort heterogeneity, and insufficient data precluded combining data to estimate incidences or rates.

RESULTS

One hundred and thirty papers with 12 704 patients were included. The median number of patients was 37 (interquartile range [IQR] 17-74, range 6-3802). Twenty-five percent of patients were initiated on IV; 75% on NIV. The maximum follow-up ranged from 0.5 to 31.8 years (median 8.8 years). The median proportion of patients liberated in these papers was 3% (IQR 0%-21%). The median proportion of mortality was 18% (IQR 8%-27%). Proportions of liberation and mortality did not significantly change over time. Progression of underlying disease (44%), respiratory illness (19%), and LTV accident (11%) were the most common causes of death.

CONCLUSIONS

These papers collectively show most patients survive for many years using LTV; in many subgroups, death is a more common outcome than liberation. However, the limitations of these papers preclude robust prognostication.

The impact of long-term ventilator-use on health-related quality of life and the mental health of children with neuromuscular diseases and their families: need for a revised perspective?

Background

Life extension by medical interventions and health-related quality of life (HRQOL) are sometimes conflicting aspects of medical care. Long-term ventilation in children with neuromuscular disease is a well-established life-extending procedure and often at the center of this conflict. HRQOL and the mental health of affected children and their families become even more important in respect to emerging therapies in neuromuscular diseases with longer life-expectancy of treated patients and considerable costs of medical treatment.

Methods

We performed a questionnaire survey in a total of forty-three families of children with neuromuscular disease treated in the University Medical Center Hamburg-Eppendorf and the Children’s Hospital Altona. We evaluated self- and proxy-reported HRQOL and mental health outcomes of affected children and their parents using validated and age-appropriate instruments.

Results

Compared to normative data, children with neuromuscular diseases and their families experienced a lower HRQOL and mental health. However, there was no additional negative influence on the overall HRQOL by ventilator use.

Conclusions

As ventilator use was not responsible for the reduction of HRQOL and mental health our data contributes an important aspect to the discussion about life-prolonging procedures, in particular mechanical ventilation, in severly disabled patients.

Polysomnography findings in pediatric spinal muscular atrophy types 1-3

BACKGROUND

Sleep disordered breathing (SDB) causes sleep disturbance and daytime symptoms in children with neuromuscular disorders. Although polysomnography (PSG) findings are well described in many neuromuscular disorders, there are limited reports from children with spinal muscular atrophy (SMA). The aim of this study was to determine the sleep architecture and breathing characteristics and non-invasive ventilation (NIV) use in our pediatric SMA cohort.

METHODS

We conducted a cross-sectional cohort study of all children with SMA in Queensland, Australia. Children were Nusinersen naïve and had a full diagnostic PSG in 2018. The PSG was scored and reported by a single pediatric sleep physician in accordance with American Academy of Sleep Medicine Criteria (2012).

RESULTS

In sum, 31 children (18 males), Six with Type 1, 16 with Type 2 and nine with Type 3, aged 0.25-18.8 years old were studied. SDB was seen in each SMA type and was more pronounced during rapid eye movement (REM) sleep. Type 1: all patients exhibited SDB, three (50%) with central sleep apnea (CSA) and three (50%) with mixed disease. Type 2: five (31%) had CSA, one (6%) mixed disease, seven (44%) had early SDB and three (19%) had normal sleep breathing. Type 3: four (44%) children had CSA and five had early SDB. No child exhibited obstructive sleep apnea (OSA) alone.Starting NIV significantly reduced mean total PSG Apnea-Hypopnea Index (AHI) scores from a grouped mean of 15.4 events per hour (SD ± 14.6; 95% CI 6.1-24.7) to 4.0 events per hour (SD ± 4.2, 95% CI 1.2-6.5, p = 0.01).

CONCLUSION

SDB is common in children with SMA and was present in all types. CSA was the most common disorder; with mixed SDB also present in type 1 and 2 SMA.

The role of sleep diagnostics and non-invasive ventilation in children with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a degenerative motor neurone disorder causing progressive muscular weakness. Without assisted ventilation or novel therapies, most children with SMA type 1 die before the second year of life due to respiratory failure as the respiratory muscles and bulbar function are severely affected. Active respiratory treatment (mechanically assisted cough, invasive or non-invasive ventilation) has improved survival significantly in recent decades, but often at the cost of becoming ventilator dependent. The advent of a new oligonucleotide based therapy (Nusinersen) has created new optimism for improving motor function. However, the long-term effect on respiratory function is unclear and non-invasive respiratory support will remain an important part of medical management in patients with SMA. This review summarises the existing knowledge about sleep-disordered breathing and respiratory failure in patients with SMA, especially type 1, as well as the evidence of improved outcome and survival in patients treated with non-invasive or invasive ventilation. Practical considerations and ethical concerns are delineated with discussion on how these may be affected by the advent of new therapies such as Nusinersen.

An observational study of functional abilities in infants, children, and adults with type 1 SMA

OBJECTIVE

To report cross-sectional clinical findings in a large cohort of patients affected by type 1 spinal muscular atrophy.

METHODS

We included 122 patients, of age ranging between 3 months and 22 years, 1 month. More than 70% (85/122) were older than 2 years and 25% (31/122) older than 10 years. Patients were classified according to the severity of phenotype and to the number of SMN2 copies.

RESULTS

Patients with the more common and the most severe phenotype older than 2 years were, with few exceptions, on noninvasive ventilation and, with increasing age, more often had tracheostomy or >16-hour ventilation and a gastrostomy inserted. In contrast, 25 of the 28 patients with the mildest phenotype older than 2 years had no need for tracheostomy or other ventilatory or nutritional support. In patients older than 2 years, the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores were generally lower compared to those found in younger patients and showed distinct levels of functional abilities according to the severity of the phenotype. Similar findings were also observed on the Hammersmith Infant Neurological Examination.

CONCLUSIONS

Our findings confirm that, after the age of 2 years, patients with type 1 spinal muscular atrophy generally survive only if they have gastrostomy and tracheostomy or noninvasive ventilation >16 hours and have low scores on the functional scales. More variability, however, can be expected in those with the mildest phenotype, who achieve head control. These data provide important baseline information at the time treatments are becoming available.

Successful use of non-invasive positive pressure ventilation in a patient with the severe form of X-linked myotubular myopathy

The severity of X-linked myotubular myopathy (XLMTM) ranges from mild to severe, depending on the level of ventilatory support required. Patients with the severe form of XLMTM usually die within the first year of life due to respiratory failure. Most survivors need tracheostomies, and there has only been one report about the use of non-invasive positive pressure ventilation (NPPV) in patients with the severe form of XLMTM because of the severity of the associated respiratory failure. We successfully applied NPPV with high-span positive inspiratory pressure (PIP) in a patient with the severe form of XLMTM, who also had secondary pectus excavatum. About a year after the initiation of NPPV with high-span PIP, the patient's pectus excavatum had improved. As the patient's pectus excavatum improved, his respiratory disturbance was ameliorated, and the frequency of respiratory infections gradually decreased. NPPV might be the first-choice respiratory management strategy for patients with XLMTM.

A multi-institutional analysis of children on long-term non-invasive respiratory support and their outcomes

OBJECTIVES

To characterize a multi-institutional cohort of children with chronic respiratory failure that use long-term, non-invasive respiratory support, perform a time-to-event analysis of transitions to transtracheal ventilation and identify factors associated with earlier transition to transtracheal ventilation.

STUDY DESIGN

A retrospective cohort study of patients less than 21 years of age with diagnoses associated with chronic respiratory failure and discharged on non-invasive respiratory support was performed using data from the Pediatric Health Information System (PHIS) between 2007 and 2015. Demographic and clinical characteristics, as well as times from index discharge on non-invasive support to transtracheal ventilation were presented. A competing risk regression model was fitted to estimate factors associated with earlier transition to transtracheal ventilation.

RESULTS

A total of 3802 patients were identified. Their median age at index discharge was 10.4 years (interquartile range [IQR] 4.1-14.9). Of these patients, 337 (8.9%) transitioned to transtracheal ventilation and transitioned at a median of 11.5 months (IQR 4.6-26) post-index discharge, or a median age of 9.3 years (IQR 4.2-14.5). Competing risk modeling demonstrated that patients who were older or whose discharge occurred later in the study period had lower hazards of earlier transition to transtracheal ventilation, whereas patients with anoxia/encephalopathy and quadriplegia had higher hazards of earlier transitioning.

CONCLUSIONS

Most patients on long-term, non-invasive respiratory support who progress to transtracheal ventilation transition do so within a few years of support initiation. Various characteristics were associated with earlier risk of transitioning to transtracheal ventilation. This information may enhance anticipatory guidance for this population.

Long-term Non-Invasive Ventilation in Infants: A Systematic Review and Meta-Analysis

BACKGROUND

The use of long-term non-invasive ventilation (NIV) to treat sleep and breathing disorders in children has increased substantially in the last decade; however, less data exist about its use in infants. Given that infants have distinct sleep and breathing patterns when compared to older children, the outcomes of infants on long-term NIV may differ as well. The aim of this study is to systematically review the use and outcomes of long-term NIV in infants.

METHODS

Ovid Medline, Ovid Embase, CINAHL (via EbscoHOST), PubMed, and Wiley Cochrane Library were systematically searched from January 1990 to July 2017. Studies on infants using long-term NIV outside of an acute care setting were included. Data were extracted on study design, population characteristics, and NIV outcomes.

RESULTS

A total of 327 studies were full-text reviewed, with final inclusion of 60. Studies were distributed across airway (40%), neuromuscular (28%), central nervous system (10%), cardio-respiratory (2%), and multiple (20%) disease categories. Of the 18 airway studies reporting on NIV outcomes, 13 (72%) reported improvements in respiratory parameters. Of the 12 neuromuscular studies exclusively on spinal muscular atrophy type 1 (SMA1), six (50%) reported decreased hospitalizations and nine (75%) reported on mortality outcomes. Risk of bias was moderate to serious, and quality of the evidence was low to very low for all studies. Most studies had an observational design with no control group, limiting the potential for a meta-analysis.

CONCLUSION

The outcomes reported in studies differed by the disease category being studied. Studies on airway conditions showed improvements in respiratory parameters for infants using NIV. Studies on neuromuscular disorder, which were almost exclusively on SMA1, reported decreased hospitalizations and prolonged survival. Overall, it appears that NIV is an effective long-term therapy for infants. However, the high risk of bias and low quality of the available evidence limited strong conclusions.

Symptom management and psychological support for families are the cornerstones of end-of-life care for children with spinal muscular atrophy type 1

AIM

This study described end-of-life care for children affected by spinal muscular atrophy type 1 (SMA1), which is characterised by progressive muscle weakness and develops in the first six months of life.

METHODS

We retrospectively analysed 17 children (13 boys) who attended the University of Padua's paediatric palliative care centre in Italy from March 2000 to March 2015. All the children received supportive care without proactive respiratory intervention to prolong survival.

RESULTS

The median age at admission was 3.57 months, and the median age at death was 6.80 months. The most frequent symptoms were dyspnoea and pain. In the last 72 hours of life, 15/17 children required more intense doses of morphine and, or, benzodiazepines for intractable dyspnoea and pain, but deep palliative sedation was not needed. Airway suction to manage secretions and nasogastric tubes was required in all cases. The place of death was previously planned by the parents in all cases - home, hospital or hospice - and 15/17 deaths occurred in that place. We also interviewed 16 of the 17 parents after their child died.

CONCLUSION

Our study found that symptom management and psychological support for families were the cornerstones of end-of-life care for children with SMA1.

Diagnosis and management of spinal muscular atrophy: Part 2: Pulmonary and acute care; medications, supplements and immunizations; other organ systems; and ethics

This is the second half of a two-part document updating the standard of care recommendations for spinal muscular atrophy published in 2007. This part includes updated recommendations on pulmonary management and acute care issues, and topics that have emerged in the last few years such as other organ involvement in the severe forms of spinal muscular atrophy and the role of medications. Ethical issues and the choice of palliative versus supportive care are also addressed. These recommendations are becoming increasingly relevant given recent clinical trials and the prospect that commercially available therapies will likely change the survival and natural history of this disease.

Spontaneous Breathing Pattern as Respiratory Functional Outcome in Children with Spinal Muscular Atrophy (SMA)

Introduction

SMA is characterised by progressive motor and respiratory muscle weakness. We aimed to verify if in SMA children 1)each form is characterized by specific ventilatory and thoraco-abdominal pattern(VTAp) during quiet breathing(QB); 2)VTAp is affected by salbutamol therapy, currently suggested as standard treatment, or by the natural history(NH) of SMA; 3)the severity of global motor impairment linearly correlates with VTAp.

Materials and methods

VTAp was analysed on 32 SMA type I (SMA1,the most severe form), 51 type II (SMA2,the moderate), 8 type III (SMA3,the mildest) and 20 healthy (HC) using opto-electronic plethysmography. Spirometry, cough and motor function were measured in a subgroup of patients.

Results

In SMA1, a normal ventilation is obtained in supine position by rapid and shallow breathing with paradoxical ribcage motion. In SMA2, ventilation is within a normal range in seated position due to an increased respiratory rate(p<0.05) with reduced tidal volume(p<0.05) secondary to a poor contribution of pulmonary ribcage(%ΔV_RC,P, p<0.001). Salbutamol therapy had no effect on VTAp during QB(p>0.05) while tachypnea occurred in type I NH. A linear correlation(p<0.001) was found between motor function scales and VTAp.

Conclusion

A negative or reduced %ΔV_RC,P, indicative of ribcage muscle weakness, is a distinctive feature of SMA1 and SMA2 since infancy. Its quantitative assessment represents a non-invasive, non-volitional index that can be obtained in all children, even uncollaborative, and provides useful information on the action of ribcage muscles that are known to be affected by the disease.Low values of motor function scales indicate impairment of motor but also of respiratory function.

Local anesthesia of the temporomandibular joint to reduce pain during mouth opening for dental treatment in a patient with spinal muscular atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive, severe neuromuscular disorder in which degeneration of alpha motor neurons in the spine progressively weakens and ultimately paralyzes the proximal muscles. It occurs in one per 6,000–10,000 infants, and is a genetic disorder with the second-highest mortality rate worldwide. An 18-year-old male patient with SMA was referred for general anesthesia for difficulty in performing dental treatment due to limited mouth opening caused by temporomandibular joint (TMJ) pain. However, the patient had a high risk of general anesthesia complications, so TMJ pain during mouth opening was reduced through local anesthesia of the TMJ. Fortunately, the anesthesia was successful in reducing pain during mouth opening, enabling the patient to receive dental treatment with an adequate mouth opening.

Clinical characteristics of three subtypes of spinal muscular atrophy in children

BACKGROUND

The severity of spinal muscular atrophy (SMA) is highly variable and children with heterogeneous clinical features can be classified into three phenotypes (type I-III) on the basis of age of onset and maximum motor function achieved. The aim of this study was to compare the clinical characteristics of three phenotypes in children with SMA.

METHODS

One hundred and thirty-two SMA patients were classified as type I, II or III according to the SMA classification criteria. The clinical features, deletion of survival motor neuron 1 (SMN1) gene and electrophysiology were analyzed and compared. The survival and functional status were obtained through telephone follow up.

RESULTS

In our study, 90.6% of the patients lacked both copies of SMNl. No difference in the deletion frequency among the 3 groups was observed. Although most of the neurophysiological parameters showed no differences among the groups, the amplitudes of compound muscle action potential (CMAP) was lower in type III SMA. Absent sensory nerve action potential (SNAP) amplitude of the sural nerve was observed in 26 (25.4%) of the patients. The survival pattern and functional status of 66 cases were obtained. Two type II SMA patients could walk unaided during follow-up. The functional ability of lower extremities improved in 4 patients with type III SMA.

CONCLUSIONS

In this study, we confirm that EMG examination and homozygous deletion of SMN1 do not correlate with the subtypes. Motor function of patients with SMA type II and III can improve. A period of follow-up is necessary before rendering accurate classification and prognosis.

Home mechanical ventilation in childhood-onset hereditary neuromuscular diseases: 13 years' experience at a single center in Korea

Introduction

Children with hereditary neuromuscular diseases (NMDs) are at a high risk of morbidity and mortality related to respiratory failure. The use of home mechanical ventilation (HMV) has saved the lives of many children with NMD but, due to a lack of studies, dependable guidelines are not available. We drew upon our experience to compare the various underlying NMDs and to evaluate HMV with regard to respiratory morbidity, the proper indications and timing for its use, and to develop a policy to improve the quality of home noninvasive ventilation (NIV).

Methods

We retrospectively analyzed the medical records of 57 children with childhood-onset hereditary NMDs in whom HMV was initiated between January 2000 and May 2013 at Seoul National University Children's Hospital. The degree of respiratory morbidity was estimated by the frequency and duration of hospitalizations caused by respiratory distress.

Results

The most common NMD was spinal muscular atrophy (SMA, n = 33). Emergent mechanical ventilation was initiated in 44% of the patients before the confirmed diagnosis, and the indicators of pre-HMV respiratory morbidity (e.g., extubation trials, hypoxia, hospitalizations, and intensive care unit stay) were greater in these patients than in others. The proportion of post-HMV hospitalizations (range, 0.00−0.52; median, 0.01) was lower than that of pre-HMV hospitalizations (0.02−1.00; 0.99) (P < 0.001). Eight patients were able to maintain home NIV. The main causes of NIV failure were air leakage and a large amount of airway secretions.

Conclusions

The application of HMV helped reduce respiratory morbidity in children with childhood-onset hereditary NMD. Patients with SMA type I can benefit from an early diagnosis and the timely application of HMV. The choice between invasive and noninvasive HMV should be based on the patient’s age and NIV trial tolerance. Systematic follow-up guidelines provided by a multidisciplinary team are needed.

The value of non-invasive ventilation

Non-invasive ventilation (NIV) use has increased markedly over the last 10 years. Children being treated with NIV are now a common sight in most paediatric intensive care units and high dependency units and nearly all tertiary respiratory units will look after a cohort of children who use NIV at home. Although the published evidence base for use of NIV in acute and chronic respiratory failure is relatively weak, it is now very unlikely that there will be any more randomised controlled trials of this intervention. Effectiveness of NIV will need to be evaluated on each child as it used. It is important to define the purpose of using NIV in each child, and then determine whether it is effective.

Non-pharmaceutical management of respiratory morbidity in children with severe global developmental delay

BACKGROUND

Children with severe global developmental delay (SGDD) have significant intellectual disability and severe motor impairment; they are extremely limited in their functional movement and are dependent upon others for all activities of daily living. SGDD does not directly cause lung dysfunction, but the combination of immobility, weakness, skeletal deformity and parenchymal damage from aspiration can lead to significant prevalence of respiratory illness. Respiratory pathology is a significant cause of morbidity and mortality for children with SGDD; it can result in frequent hospital admissions and impacts upon quality of life. Although many treatment approaches are available, there currently exists no comprehensive review of the literature to inform best practice. A broad range of treatment options exist; to focus the scope of this review and allow in-depth analysis, we have excluded pharmaceutical interventions.

OBJECTIVES

To assess the effects of non-pharmaceutical treatment modalities for the management of respiratory morbidity in children with severe global developmental delay.

SEARCH METHODS

We conducted comprehensive searches of the following databases from inception to November 2013: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Allied and Complementary Medicine Database (AMED) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We searched the Web of Science and clinical trials registries for grey literature and for planned, ongoing and unpublished trials. We checked the reference lists of all primary included studies for additional relevant references.

SELECTION CRITERIA

Randomised controlled trials, controlled trials and cohort studies of children up to 18 years of age with a diagnosis of severe neurological impairment and respiratory morbidity were included. Studies of airways clearance techniques, suction, assisted coughing, non-invasive ventilation, tracheostomy and postural management were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by The Cochrane Collaboration. As the result of heterogeneity, we could not perform meta-analysis. We have therefore presented our results using a narrative approach.

MAIN RESULTS

Fifteen studies were included in the review. Studies included children with a range of severe neurological impairments in differing settings, for example, home and critical care. Several different treatment modalities were assessed, and a wide range of outcome measures were used. Most studies used a non-randomised design and included small sample groups. Only four randomised controlled trials were identified. Non-randomised design, lack of information about how participants were selected and who completed outcome measures and incomplete reporting led to high or unclear risk of bias in many studies. Results from low-quality studies suggest that use of non-invasive ventilation, mechanically assisted coughing, high-frequency chest wall oscillation (HFCWO), positive expiratory pressure and supportive seating may confer potential benefits. No serious adverse effects were reported for ventilatory support or airway clearance interventions other than one incident in a clinically unstable child following mechanically assisted coughing. Night-time positioning equipment and spinal bracing were shown to have a potentially negative effect for some participants. However, these findings must be considered as tentative and require testing in future randomised trials.

AUTHORS' CONCLUSIONS

This review found no high-quality evidence for any single intervention for the management of respiratory morbidity in children with severe global developmental delay. Our search yielded data on a wide range of interventions of interest. Significant differences in study design and in outcome measures precluded the possibility of meta-analysis. No conclusions on efficacy or safety of interventions for respiratory morbidity in children with severe global developmental delay can be made based upon the findings of this review.A co-ordinated approach to future research is vital to ensure that high-quality evidence becomes available to guide treatment for this vulnerable patient group.

Spinal muscular atrophy: a motor neuron disorder or a multi-organ disease?

Spinal muscular atrophy (SMA) is an autosomal recessive disorder that is the leading genetic cause of infantile death. SMA is characterized by loss of motor neurons in the ventral horn of the spinal cord, leading to weakness and muscle atrophy. SMA occurs as a result of homozygous deletion or mutations in Survival Motor Neuron-1 (SMN1). Loss of SMN1 leads to a dramatic reduction in SMN protein, which is essential for motor neuron survival. SMA disease severity ranges from extremely severe to a relatively mild adult onset form of proximal muscle atrophy. Severe SMA patients typically die mostly within months or a few years as a consequence of respiratory insufficiency and bulbar paralysis. SMA is widely known as a motor neuron disease; however, there are numerous clinical reports indicating the involvement of additional peripheral organs contributing to the complete picture of the disease in severe cases. In this review, we have compiled clinical and experimental reports that demonstrate the association between the loss of SMN and peripheral organ deficiency and malfunction. Whether defective peripheral organs are a consequence of neuronal damage/muscle atrophy or a direct result of SMN loss will be discussed.

Survival of patients with spinal muscular atrophy type 1

BACKGROUND

Spinal muscular atrophy type 1 (SMA1) is a progressive disease and is usually fatal in the first year of life.

METHODS

A retrospective chart review was performed of SMA1 patients and their outcomes according to the following choices: letting nature take its course (NT); tracheostomy and invasive mechanical ventilation (TV); continuous noninvasive respiratory muscle aid (NRA), including noninvasive ventilation; and mechanically assisted cough.

RESULTS

Of 194 consecutively referred patients enrolled in this study (103 males, 91 females), NT, TV, and NRA were chosen for 121 (62.3%), 42 (21.7%), and 31 (16%) patients, respectively. Survival at ages 24 and 48 months was higher in TV than NRA users: 95% (95% confidence interval: 81.8%-98.8%) and 67.7% (95% confidence interval: 46.7%-82%) at age 24 months (P < .001) and 89.43% and 45% at age 48 months in the TV and NRA groups, respectively (P < .001). The choice of TV decreased from 50% (1992-1998) to 12.7% (2005-2010) (P < .005) with a nonstatistically significant increase for NT from 50% to 65%. The choice of NRA increased from 8.1% (1999-2004) to 22.7% (2005-2010) (P < .001).

CONCLUSIONS

Long-term survival outcome is determined by the choice of the treatment. NRA and TV can prolong survival, with NRA showing a lower survival probability at ages 24 and 48 months.

Noninvasive respiratory management and diaphragm and electrophrenic pacing in neuromuscular disease and spinal cord injury

The purpose of this monograph is to describe noninvasive management of respiratory muscle weakness/paralysis for patients with neuromuscular disease (NMD) and spinal cord injury (SCI). Noninvasive ventilation (NIV) assists and supports inspiratory muscles, whereas mechanically assisted coughing (MAC) simulates an effective cough. Long-term outcomes will be reviewed as well as the use of NIV, MAC, and electrophrenic pacing (EPP) and diaphragm pacing (DP) to facilitate extubation and decannulation. Although EPP and DP can facilitate decannulation and maintain alveolar ventilation for high-level SCI patients when they cannot use NIV because of lack of access to oral interfaces, there is no evidence that they have any place in the management of NMD.

Hypoxia is a modifier of SMN2 splicing and disease severity in a severe SMA mouse model

Spinal muscular atrophy (SMA) is a progressive neurodegenerative disease associated with low levels of the essential survival motor neuron (SMN) protein. Reduced levels of SMN is due to the loss of the SMN1 gene and inefficient splicing of the SMN2 gene caused by a C>T mutation in exon 7. Global analysis of the severe SMNΔ7 SMA mouse model revealed altered splicing and increased levels of the hypoxia-inducible transcript, Hif3alpha, at late stages of disease progression. Severe SMA patients also develop respiratory deficiency during disease progression. We sought to evaluate whether hypoxia was capable of altering SMN2 exon 7 splicing and whether increased oxygenation could modulate disease in a severe SMA mouse model. Hypoxia treatment in cell culture increased SMN2 exon 7 skipping and reduced SMN protein levels. Concordantly, the treatment of SMNΔ7 mice with hyperoxia treatment increased the inclusion of SMN2 exon 7 in skeletal muscles and resulted in improved motor function. Transfection splicing assays of SMN minigenes under hypoxia revealed that hypoxia-induced skipping is dependent on poor exon definition due to the SMN2 C>T mutation and suboptimal 5' splice site. Hypoxia treatment in cell culture led to increased hnRNP A1 and Sam68 levels. Mutation of hnRNP A1-binding sites prevented hypoxia-induced skipping of SMN exon 7 and was found to bind both hnRNP A1 and Sam68. These results implicate hypoxic stress as a modulator of SMN2 exon 7 splicing in disease progression and a coordinated regulation by hnRNP A1 and Sam68 as modifiers of hypoxia-induced skipping of SMN exon 7.

Spinal muscular atrophy type 1: are proactive respiratory interventions associated with longer survival?

CONTEXT

Spinal muscular atrophy type 1, an autosomal recessive motor neuron disease, is a leading genetic cause of death in infancy and early childhood.

OBJECTIVE

To determine whether the early initiation of noninvasive respiratory interventions is associated with longer survival.

DESIGN

Single-institution retrospective cohort study identified children with spinal muscular atrophy type 1 from January 1, 2002 to May 1, 2009 who were followed for 2.3 mean yrs.

SETTING

Tertiary care children's hospital and outpatient clinics in a vertically integrated healthcare system.

PATIENTS OR OTHER PARTICIPANTS

Forty-nine children with spinal muscular atrophy type 1 were grouped according to the level of respiratory support their caregivers chose within the first 3 months after diagnosis: proactive respiratory care (n = 26) and supportive care (n = 23).

INTERVENTIONS

Proactive respiratory care included bilevel noninvasive ventilation during sleep and twice a day cough assist while supportive respiratory care included suctioning, with or without supplemental oxygen.

MEASUREMENTS AND MAIN RESULTS

Kaplan-Meier survival curves were assessed based on intention to treat. Children treated with early proactive respiratory support had statistically longer survival compared to supportive care (log rank 0.047); however, the adjusted hazard ratio for survival was not statistically different (2.44 [95% confidence interval 0.84-7.1]). Children in the proactive group were more likely to be hospitalized for respiratory insufficiency (83% vs. 46%) and had shortened time after diagnosis until first hospital admission for respiratory insufficiency (median 118 vs. 979 days).

CONCLUSION

Longer survival time with spinal muscular atrophy type 1 is associated with early, noninvasive respiratory care interventions after diagnosis.

The natural course of infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1)

BACKGROUND

Only scarce information is available on the long-term outcome and the natural course of children with infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1) due to mutations in the IGHMBP2 gene.

OBJECTIVE

To describe the natural disease course, to systematically quantify the residual capacities of children with SMARD1 who survive on permanent mechanical respiration, and to identify markers predicting the disease outcome at the time of manifestation.

METHODS

We conducted a longitudinal study of 11 infantile SMARD1 patients over a mean observational period of 7.8 (SD 3.2) years. Disease-specific features were continuously assessed by using a semiquantitative scoring system. Additionally, we analyzed the residual enzymatic activity of 6 IGHMBP2 mutants in our patients.

RESULTS

After an initial rapid decline of the clinical score until the age of 2 years, residual capabilities reached a plateau or even improved. The overall clinical outcome was markedly heterogeneous, but clinical scores at the age of 3 months showed a positive linear correlation with the clinical outcome at 1 year and at 4 years of age. If expressed in an in vitro recombinant system, mutations of patients with more favorable outcomes retained residual enzymatic activity.

CONCLUSIONS

Despite their severe disabilities and symptoms, most SMARD1 patients are well integrated into their home environment and two thirds of them are able to attend kindergarten or school. This information will help to counsel parents at the time of disease manifestation.

Chronic respiratory failure and neuromuscular disease

The outlook for children with respiratory complications of neuromuscular disease has improved significantly in the past 15 years. This has been the result of many advances in clinical care, including improved monitoring of lung function and hypoventilation during sleep; coordinated respiratory care by experienced physicians with access to specialized respiratory services, especially physiotherapy; and, most importantly, the widespread introduction of noninvasive ventilation.

Lung insufflation capacity in neuromuscular disease

OBJECTIVE

To compare maximal passive lung insufflation capacity (LIC) with lung inflation by air stacking (to maximum insufflation capacity [MIC]) and with vital capacity (VC); to explore relationships between these variables that correlate with glottic function and cough peak flows (CPF); to demonstrate the effect of routine inflation therapy on LIC and MIC; and to determine the relative importance of lung inflation therapy as a function of disease severity.

DESIGN

Case series of 282 consecutive neuromuscular disease (NMD) clinic patients 7 yrs and older with VC <70% of the predicted normal value. All cooperative patients meeting these criteria were prescribed thrice-daily air stacking and/or maximal passive lung insufflation to pressures of 40-80 cm H2O, and they underwent measurements of VC, MIC, LIC, and unassisted and assisted CPF on every visit.

RESULTS

Means +/- standard deviations for VC, MIC, and LIC were 1131 +/- 744, 1712 +/- 926, and 2069 +/- 867 ml, respectively, and, for unassisted and assisted CPF, they were 2.5 +/- 2.0 and 4.3 +/- 2.2 liters/sec, respectively, with all differences statistically significant (P < 0.001). MIC minus VC correlated inversely with LIC minus MIC (P = 0.01) and, therefore, with glottic function. Both MIC and LIC increased with practice (P < 0.001). Increases in LIC but not MIC over VC were greatest for patients with the lowest VC (P < 0.05). There were no complications of lung mobilization therapy.

CONCLUSIONS

Passive lung insufflation can distend the lungs of patients with NMD significantly greater than air stacking, particularly when glottic and bulbar-innervated muscle dysfunction is severe. LIC, MIC, and VC measurements permit quantifiable assessment of glottic integrity and, therefore, bulbar-innervated muscle function for patients with NMD. The patients who benefit the most from insufflation therapy are those who have the lowest VC.

Reduced SMN protein impairs maturation of the neuromuscular junctions in mouse models of spinal muscular atrophy

Spinal muscular atrophy (SMA) is a common pediatric neuromuscular disorder caused by insufficient levels of the survival of motor neuron (SMN) protein. Studies involving SMA patients and animal models expressing the human SMN2 gene have yielded relatively little information about the earliest cellular consequences of reduced SMN protein. In this study, we have used severe- and mild-SMN2 expressing mouse models of SMA as well as material from human patients to understand the initial stages of neurodegeneration in the human disease. We show that the earliest structural defects appear distally and involve the neuromuscular synapse. Insufficient SMN protein arrests the post-natal development of the neuromuscular junction (NMJ), impairing the maturation of acetylcholine receptor (AChR) clusters into 'pretzels'. Pre-synaptic defects include poor terminal arborization and intermediate filament aggregates which may serve as a useful biomarker of the disease. These defects are reflected in functional deficits at the NMJ characterized by intermittent neurotransmission failures. We suggest that SMA might best be described as a NMJ synaptopathy and that one promising means of treating it could involve maintaining function at the NMJ.