Nusinersen in adults with type 3 spinal muscular atrophy: long-term outcomes on motor and respiratory function

INTRODUCTION

Nusinersen was approved for 5q spinal muscular atrophy (SMA), irrespective of age, SMA type or functional status. Nonetheless, long-term data on adults with milder phenotypes are scarce. We aimed to characterize evolution on motor and respiratory function in our cohort of adults with type 3 SMA.

METHODS

We conducted a longitudinal retrospective single-center study, including adults (≥18 years) with type 3 SMA under nusinersen for > 22 months. We reported on motor scores and spirometry parameters.

RESULTS

Ten patients were included, with a median follow-up of 34 months (range = 22-46). Four patients (40%) were walkers. None used non-invasive ventilation. In Revised Upper Limb Module (RULM) and Expanded Hammersmith Functional Motor Scale (HFMSE), difference of medians increased at 6, 22 and 46 months comparing to baseline (-0.5 vs. + 1.5 vs. + 2.5 in RULM; + 4.0 vs. + 7.5 vs. + 6.0 in HFMSE). Two (50%) walkers presented a clinically meaningful improvement in 6-min walk distance. We did not report any clinically meaningful decrement in motor scores. Spirometry parameters showed an increasing difference of medians in maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) (-3 vs. + 13.4 vs. + 28.7 percentage points of predicted value for MIP; + 11.8 vs. + 13.1 vs. 13.3 percentage points of predicted value for MEP).

DISCUSSION

Our cohort supports a sustained benefit of nusinersen in adults with type 3 SMA, in motor and respiratory function. Multicentric studies are still warranted.

Monitoring spinal muscular atrophy with three-dimensional optoacoustic imaging

BACKGROUND

Spinal muscular atrophy is a progressive neuromuscular disorder and among the most frequent genetic causes of infant mortality. While recent advancements in gene therapy provide the potential to ameliorate the disease severity, there is currently no modality in clinical use to visualize dynamic pathophysiological changes in disease progression and regression after therapy.

METHODS

In this prospective diagnostic clinical study, ten pediatric patients with spinal muscular atrophy and ten age- and sex-matched controls have been examined with three-dimensional optoacoustic imaging and clinical standard examinations to compare the spectral profile of muscle tissue and correlate it with motor function (ClinicalTrials.gov: NCT04115475).

FINDINGS

We observed a reduced optoacoustic signal in muscle tissue of pediatric patients with spinal muscular atrophy. The reduction in signal intensity correlated with disease severity as assessed by grayscale ultrasound and standard motor function tests. In a cohort of patients who received disease-modifying therapy prior to the study, the optoacoustic signal intensity was similar to healthy controls.

CONCLUSIONS

This translational study provides early evidence that three-dimensional optoacoustic imaging could have clinical implications in monitoring disease activity in spinal muscular atrophy. By visualizing and quantifying molecular changes in muscle tissue, disease progression and effects of gene therapy can be assessed in real time.

FUNDING

The project was funded by ELAN Fonds (P055) at the University Hospital of the Friedrich-Alexander-Universität (FAU) Erlangen-Nurnberg to A.P.R.

Risdiplam improves subjective swallowing quality in non-ambulatory adult patients with 5q-spinal muscular atrophy despite advanced motor impairment

BACKGROUND

5q-associated spinal muscular atrophy (SMA) is characterized by the progressive loss of motor neurons with consecutive weakness and atrophy of the limb, respiratory, and bulbar muscles. While trunk and limb motor function improve or stabilize in adults with SMA under nusinersen and risdiplam treatment, the efficacy on bulbar function in this age group of patients remains uncertain. However, it is important to assess bulbar dysfunction, which frequently occurs in the disease course and is associated with increased morbidity and mortality.

METHODS

Bulbar function was evaluated prospectively in 25 non-ambulatory adults with type 2 and 3 SMA before and 4 and 12 months after risdiplam treatment initiation using the Sydney Swallow Questionnaire (SSQ) and the bulbar subscore of the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (b-ALSFRS-R). Extremity function was assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM).

RESULTS

Subjective swallowing quality, measured with the SSQ, improved after 12 months of therapy with risdiplam. For the b-ALSFRS-R, a non-significant trend towards improvement was observed. The RULM score improved after 12 months of risdiplam therapy, but not the HFMSE score. HFMSE and RULM scores did not correlate with the SSQ but the b-ALSFRS-R score at baseline.

CONCLUSIONS

The improvement in subjective swallowing quality under risdiplam treatment, despite an advanced disease stage with severe motor deficits, strengthens the importance of a standardized bulbar assessment in addition to established motor scores. This may reveal relevant treatment effects and help individualize treatment decisions in the future.

Natural History of Mandibular Function in Spinal Muscular Atrophy Types 2 and 3

Background

Hereditary proximal spinal muscular atrophy (SMA) is characterized by abnormal alpha motor neuron function in brainstem and spinal cord. Bulbar dysfunction, including limited mouth opening, is present in the majority of patients with SMA but it is unknown if and how these problems change during disease course.

Objective

In this prospective, observational, longitudinal natural history study we aimed to study bulbar dysfunction in patients with SMA types 2 and 3.

Methods

We included 44 patients with SMA types 2 and 3 (mean age was 33.6 (95% CI 28.4;38.9) and re-examined them after on average 4 years. None were treated with SMN-modulating treatments before or during the course of this study. Longitudinal assessments included a questionnaire on mandibular and bulbar function, the Mandibular Function Impairment Questionnaire (MFIQ), and a clinical examination of masticatory performance, maximum voluntary bite force, and mandibular movements including the active maximal mouth opening.

Results

We found significant higher MFIQ scores and a significant decrease of all mandibular movements in patients with SMA type 2 (p < 0.001), but not in SMA type 3. Masticatory performance and maximum voluntary bite force did not change significantly. Mean reduction of active maximal mouth opening at follow-up was 3.5 mm in SMA type 2 (95% CI: 2.3; 4.7, p < 0.001). SMA type 2 was an independent predictor for a more severe reduction of the mouth opening (β= -2.0 mm (95% CI: -3.8; -0.1, p = 0.043)).

Conclusions

Bulbar functions such as mandibular mobility and active maximum mouth opening decrease significantly over the course of four years in patients with SMA type 2.

Disease Trajectories in the Revised Hammersmith Scale in a Cohort of Untreated Patients with Spinal Muscular Atrophy types 2 and 3

Background

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterised by progressive motor function decline. Motor function is assessed using several functional outcome measures including the Revised Hammersmith Scale (RHS).

Objective

In this study, we present longitudinal trajectories for the RHS in an international cohort of 149 untreated paediatric SMA 2 and 3 patients (across 531 assessments collected between March 2015 and July 2019).

Methods

We contextualise these trajectories using both the Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM). At baseline, this cohort included 50% females and 15% of patients had undergone spinal fusion surgery. Patient trajectories were modelled using a natural cubic spline with age, sex, and random effects for each patient.

Results

RHS and HFMSE scores show similar trends over time in this cohort not receiving disease modifying therapies. The results confirm the strong correlation between the RHS and RULM previously observed in SMA types 2 and 3a. Scoliosis surgery is associated with a reduction of 3 points in the RHS, 4.5 points in the HFMSE for the SMA 2 population, and a reduction of 11.8 points in the RHS, and 13.4 points in the HFMSE for the SMA 3a populations. When comparing the RHS and RULM, there is a lower correlation in the type 3a's than the type 2 patients. In the SMA 2 population, there is no significant difference between the sexes in either the RHS or HFMSE trajectories. There is no significant difference in the RULM trajectory in the SMA 2 or 3a participants by sex.

Conclusions

This study demonstrates that the RHS could be used in conjunction with other functional measures such as the RULM to holistically detect SMA disease progression. This will assist with fully understanding changes that occur with treatments, further defining trajectories and therapy outcomes.

Cardiac function evaluation in children with spinal muscular atrophy: A case-control study

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by degeneration of lower motor neurons, resulting in progressive muscle weakness and atrophy. However, little is known regarding the cardiac function of children with SMA.

METHODS

We recruited SMA patients younger than 18 years of age from January 1, 2022, to April 1, 2022, in the First Affiliated Hospital of Sun Yat-sen University. All patients underwent a comprehensive cardiac evaluation before treatment, including history taking, physical examination, blood tests of cardiac biomarkers, assessment of echocardiography and electrocardiogram. Age/gender-matched healthy volunteers were recruited as controls.

RESULTS

A total of 36 SMA patients (26 with SMA type 2 and 10 with SMA type 3) and 40 controls were enrolled in the study. No patient was clinically diagnosed with heart failure. Blood tests showed elevated values of creatine kinase isoenzyme M and isoenzyme B (CK-MB) mass and high-sensitivity cardiac troponin T (hs-cTnT) in spinal muscular atrophy (SMA) patients. Regarding echocardiographic parameters, SMA children were detected with lower global left and right ventricular longitudinal strain, abnormal diastolic filling velocities of trans-mitral and trans-tricuspid flow. The results revealed no clinical heart dysfunction in SMA patients, but subclinical ventricular dysfunction was seen in SMA children including the diastolic function and myocardial performance. Some patients presented with elevated heart rate and abnormal echogenicity of aortic valve or wall. Among these SMA patients, seven patients (19.4%) had scoliosis. The Cobb's angles showed a significant negative correlation with LVEDd/BSA, but no correlation with other parameters, suggesting that mild scoliosis did not lead to significant cardiac dysfunction.

CONCLUSIONS

Our findings warrant increased attention to the cardiac status and highlight the need to investigate cardiac interventions in SMA children.

Dysphagia and Lung Disease in Children With Spinal Muscular Atrophy Treated With Disease-Modifying Agents

OBJECTIVES

Disease-modifying agents (DMAs) for the treatment of spinal muscular atrophy (SMA) have evolved the SMA phenotype with improved survival. Ongoing oropharyngeal dysphagia and respiratory complications are reported. The extent of dysphagia and respiratory morbidity in this population, since DMAs' introduction, has not been well described.

METHODS

A whole-population study involved all children with treated SMA types 1-3 in our facility. Videofluoroscopic swallow studies (type 1 alone), chest CT scans, and clinical data were collected.

RESULTS

Thirty-six children were included (n = 9 type 1, n = 14 type 2, and n = 13 type 3; age range 0.3-15.4 years). Abnormal swallowing characteristics were demonstrated in all children with type 1 (n = 8; 100%). Bronchiectasis was found on chest CT: 3 of 9 (33.3%), 2 of 14 (14.3%), and 2 of 13 (15.4%) of type 1, 2, and 3, respectively. Atelectasis, mucus plugging, bronchial wall thickening, and parenchymal changes were common.

DISCUSSION

Swallow impairments were universal in children with type 1. Bronchiectasis was common in all pediatric SMA types, with a prevalence of 1 in 5. Routine monitoring and management of dysphagia/recurrent respiratory infection should be implemented for improvement in lung health.

Dual SMN inducing therapies can rescue survival and motor unit function in symptomatic ∆7SMA mice

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by survival motor neuron (SMN) protein deficiency which results in motor neuron loss and muscle atrophy. SMA is caused by a mutation or deletion of the survival motor neuron 1 (SMN1) gene and retention of the nearly identical SMN2 gene. SMN2 contains a C to T change in exon 7 that results in exon 7 exclusion from 90% of transcripts. SMN protein lacking exon 7 is unstable and rapidly degraded. The remaining full-length transcripts from SMN2 are insufficient for normal motor neuron function leading to the development of SMA. Three different therapeutic approaches that increase full-length SMN (FL-SMN) protein production are approved for treatment of SMA patients. Studies in both animal models and humans have demonstrated increasing SMN levels prior to onset of symptoms provides the greatest therapeutic benefit. Treatment of SMA, after some motor neuron loss has occurred, is also effective but to a lesser degree. The SMN∆7 mouse model is a well characterized model of severe or type 1 SMA, dying at 14 days of age. Here we treated three groups of ∆7SMA mice starting before, roughly during, and after symptom onset to determine if combining two mechanistically distinct SMN inducing therapies could improve the therapeutic outcome both before and after motor neuron loss. We found, compared with individual therapies, that morpholino antisense oligonucleotide (ASO) directed against ISS-N1 combined with the small molecule compound RG7800 significantly increased FL-SMN transcript and protein production resulting in improved survival and weight of ∆7SMA mice. Moreover, when give late symptomatically, motor unit function was completely rescued with no loss in function at 100 days of age in the dual treatment group. We have therefore shown that this dual therapeutic approach successfully increases SMN protein and rescues motor function in symptomatic ∆7SMA mice.

Functional and surgical treatments in patients with spinal muscular atrophy (SMA)

Spinal muscular atrophies (SMA type 1, 2, 3) present with various severities according to the motor semeiology related to lesions of the peripheral nervous system (lesions of the anterior horn cells motoneuron or even brain stem). Early motor deficiency causes skeletal deformities responsible for the alteration or even absence of motor skills acquisition. The management of these patients involves several practitioners: pediatric neurologist, pediatric pneumologist, physical medicine and rehabilitation therapist, pediatric orthopedic surgeon, psychologist, physiotherapist, etc. Therefore, this multidisciplinary management must take place in a reference center. This has allowed for improvement of the natural history of SMA. Despite the severity of clinical presentation, especially in SMA type 1 or 2, the functional aspect is always to be taken into account in the first instance. Furthermore, the natural history of the disease is currently being modified by the emergence of innovative therapies that will change the evolution of the disease and its management. Indeed, current treatment objectives are the comfort of installation and the fight against neuro-orthopedic degradation. Although the rise in the number of innovative therapies has led to increased expectancies, such as motor function improvement, practitioners should be aware that these innovative treatments should be balanced against child development and the disease's natural history. Scoliosis surgery is almost systematic in SMA type 2 because of trunk muscular deficiency, especially intercostal muscle insufficiency, and spino-pelvic complex disorder. However, surgical techniques have evolved to become less invasive and more growth friendly in order to follow child development. The final goal of surgery in SMA patients is to obtain a 3-dimensional deformity correction along with a spino-pelvic realignment in order to allow for a comfortable seated position, which is the position of function in these patients, and to allow for better ventilation. Faced with this global approach and innovative therapies, global assessment is warranted not solely in an isolated manner, as is usually the case during hospital stays with traditional scales, but rather during daily activities. This is the case of daily monitoring, which allows for motor skill and activity assessments throughout the day. The principle is to characterize, according to SMA type and treatment, the activity type (standing, seated, walking), duration, intensity and frequency. The ultimate goal would be to identify the variety and occurrence of motor activities, and finally to clarify if the different treatments, including innovative therapies, lead to functional improvement in these patients. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Electrical impedance tomography detects changes in ventilation after airway clearance in spinal muscular atrophy type I

The effect of mechanical insufflation-exsufflation (MIE) for airway clearance in patients with spinal muscular atrophy type I (SMA-I) on the distribution of ventilation in the lung is unknown, as is the duration of its beneficial effects. A pilot study to investigate the feasibility of using three dimensional (3-D) electrical impedance tomography (EIT) images to estimate lung volumes pre- and post-MIE for assessing the effectiveness of mechanical insufflation-exsufflation (MIE) was conducted in 6 pediatric patients with SMA-I in the neuromuscular clinic at Children's Hospital Colorado. EIT data were collected before, during, and after the MIE procedure on two rows of 16 electrodes placed around the chest. Lung volumes were computed from the images and compared before, during, and after the MIE procedure to assess the ability of EIT to estimate changes in lung volume during insufflation and exsufflation. Images of pulsatile pulmonary perfusion were computed in subjects able to perform breath-holding. In four of the six subjects, lung volumes during tidal breathing increased after MIE (average change from pre to post MIE was 58.8±55.1 mL). The time-dependent plots of lung volume computed from the EIT data clearly show when the MIE device insufflates and exsufflates air and the rest periods between mechanical coughs. Images of pulmonary pulsatile perfusion were computed from data collected during breathing pauses. The results suggest that EIT holds promise for estimating lung volumes and ventilation/perfusion mismatch, both of which are useful for assessing the effectiveness of MIE in clearing mucus plugs.

Risdiplam-Treated Infants with Type 1 Spinal Muscular Atrophy versus Historical Controls

BACKGROUND

Type 1 spinal muscular atrophy (SMA) is a progressive neuromuscular disease characterized by an onset at 6 months of age or younger, an inability to sit without support, and deficient levels of survival of motor neuron (SMN) protein. Risdiplam is an orally administered small molecule that modifies SMN2 pre-messenger RNA splicing and increases levels of functional SMN protein in blood.

METHODS

We conducted an open-label study of risdiplam in infants with type 1 SMA who were 1 to 7 months of age at enrollment. Part 1 of the study (published previously) determined the dose to be used in part 2 (reported here), which assessed the efficacy and safety of daily risdiplam as compared with no treatment in historical controls. The primary end point was the ability to sit without support for at least 5 seconds after 12 months of treatment. Key secondary end points were a score of 40 or higher on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND; range, 0 to 64, with higher scores indicating better motor function), an increase of at least 4 points from baseline in the CHOP-INTEND score, a motor-milestone response as measured by Section 2 of the Hammersmith Infant Neurological Examination (HINE-2), and survival without permanent ventilation. For the secondary end points, comparisons were made with the upper boundary of 90% confidence intervals for natural-history data from 40 infants with type 1 SMA.

RESULTS

A total of 41 infants were enrolled. After 12 months of treatment, 12 infants (29%) were able to sit without support for at least 5 seconds, a milestone not attained in this disorder. The percentages of infants in whom the key secondary end points were met as compared with the upper boundary of confidence intervals from historical controls were 56% as compared with 17% for a CHOP-INTEND score of 40 or higher, 90% as compared with 17% for an increase of at least 4 points from baseline in the CHOP-INTEND score, 78% as compared with 12% for a HINE-2 motor-milestone response, and 85% as compared with 42% for survival without permanent ventilation (P<0.001 for all comparisons). The most common serious adverse events were pneumonia, bronchiolitis, hypotonia, and respiratory failure.

CONCLUSIONS

In this study involving infants with type 1 SMA, risdiplam resulted in higher percentages of infants who met motor milestones and who showed improvements in motor function than the percentages observed in historical cohorts. Longer and larger trials are required to determine the long-term safety and efficacy of risdiplam in infants with type 1 SMA. (Funded by F. Hoffmann-La Roche; FIREFISH ClinicalTrials.gov number, NCT02913482.).

Cardiovascular and sudomotor dysfunction in Hirayama disease

Hirayama disease is a disease of young males causing atrophy of small muscles of the affected hand and forearm. Localized autonomic dysfunction of the affected upper limb such as cold skin and excessive sweating has been described in some patients. In this study, we looked for local as well as systemic involvement of autonomic nervous system in patients with Hirayama disease. Forty-four patients with a median duration of illness of 3 years were included in the study. Assessment of symptom profile and evaluation of autonomic nervous system were done at the time of enrolment. The mean age at presentation was 21.9 (10-32) years, with a delay in seeking medical attention of around 3 (1-11) years. Localized clinical autonomic dysfunction was present in 39 (88.6%) patients, while objective generalized autonomic dysfunction was present in 33 (75%) patients. Cold skin and excessive sweating showed good correlation with the presence of objective autonomic dysfunction (P < 0.05). In three patients, sympathetic skin response (SSR) could not be recorded in one of the four limbs. Compared to controls, the SSR results in patients with Hirayama disease showed increased latency (1.64 ± 0.21 vs. 1.57 ± 0.14, P 0.04) and decreased amplitude in upper limbs (0.65 ± 0.19 vs. 0.86 ± 0.40, P 0.01). Hirayama disease has both localized and systemic dysautonomia. Careful longitudinal evaluation during the progressive phase of the disease may help in diagnosing subtle systemic autonomic dysfunction.

The Influence of "Loss of Attachment" on the Outcome of Anterior Cervical Fusion Procedures in Patients With Hirayama Disease

The objective of this study was to identify the influence of the measurements of "loss of attachment" on the surgical outcome in Hirayama disease (HD). Forty-two patients with HD underwent neutral and cervical-flexion magnetic resonance imaging (MRI) before surgery, and the cervical-flexion MRI was repeated at the 3-month postoperative visit. The longitudinal separation range (LSR) of loss of attachment, the maximum forward-shifting (MFS) degree in the cervical cord, and the relative morphological changes of the cervical cord were measured on MRI. Additionally, all patients underwent handgrip strength (HGS) testing, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and Medical Research Council scales at the 1-year postoperative visit. Postoperatively, the cervical-flexion X/Y and the LSR decreased significantly at a mean of 94.17±8.65 days (range, 75-110 days) (P<.01), while the cervical-flexion A/B increased (P<.01). Loss of attachment was resolved in fused segments in all 42 patients, but there were 7 instances of residual loss of attachment at adjacent segments. Twenty (47.6%) of the 42 patients' DASH scores decreased at the 1-year postoperative visit. According to the logistic regression analysis, both LSR and MFS were related to the surgical outcomes. Receiver operating characteristic curve analysis found that area under the curve and cutoff values were 0.959 and 4.5, respectively (P<.05) for LSR and 0.782 and 0.215, respectively (P<.05) for MFS. Anterior cervical fusion procedures can effectively improve the abnormal loss of attachment and prevent further progression of HD. The LSR is an important risk factor for the prognosis, and longer fused segments may be required when the LSR is 5 segments or more. [Orthopedics. 2021;44(1):30-37.].

Improvement of Pulmonary Function Measured by Patient-reported Outcomes in Patients With Spinal Muscular Atrophy After Growth-friendly Instrumentation

BACKGROUND

Children with spinal muscular atrophy (SMA) sustain a progressive reduction in pulmonary function (PF) related to both muscular weakness and the concomitant effects of spinal deformity on the thorax. Growth-friendly instrumentation is commonly utilized for younger patients with scoliosis and SMA to halt the progression of spinal curvature, but its effect on PF in these patients has not previously been investigated. Using the change in Early Onset Scoliosis 24-Item Questionnaire (EOSQ-24) PF subdomain scores, the authors will investigate whether PF improves in patients with SMA after a growth-friendly intervention.

METHODS

This was a multicenter retrospective cohort study from 2 international registries of patients with SMA undergoing spinal deformity surgery from 2005 to 2015. Data collected were age, sex, degree of major coronal curve, type of growth-friendly construct, forced vital capacity (FVC), and EOSQ-24 scores at the patient's preoperative, 1-year postoperative, and 2-year postoperative visits. Differences in EOSQ-24 PF scores and FVC between baseline and postoperative assessment were examined by paired tests.

RESULTS

A total of 74 patients were identified (mean age, 7.6±2.3 y, major curve 68.1±22.4 degrees, 51.4% female individuals). The mean EOSQ-24 PF scores improved significantly from 70.6 preoperatively to 83.6 at 1 year (P=0.092) and 86.5 at 2 years postoperatively (P=0.020). The scores in patients with rib-based constructs showed steeper increases at 1-year assessments than those in patients with spine-based constructs. The mean paired FVC value decreased from 63.9% predicted preoperatively, to 57.6% predicted at 1 year postoperatively (P=0.035), and 61.9% predicted preoperatively, to 56.3% predicted at 2 years postoperatively (P=0.178).

CONCLUSIONS

Patients with SMA who received growth-friendly instrumentation did experience improvements in PF as measured by EOSQ-24 assessing the caregivers' perception. Given the uncertain reliability of PFTs in this young population, EOSQ-24 is an important tool for measuring improvements in health-related quality of life.

LEVEL OF EVIDENCE

Level III-retrospective study.

Assessment of the validity and reliability of the 32-item Motor Function Measure in individuals with Type 2 or non-ambulant Type 3 spinal muscular atrophy

The 32-item Motor Function Measure (MFM32) is an assessment of motor function, and its measurement properties were established in a broad neuromuscular disease population. This study sought to investigate the reliability, validity, and ability to detect change of MFM32 in individuals with Type 2 and non-ambulant Type 3 spinal muscular atrophy (SMA). Data were used from the Phase 2 study assessing the efficacy and safety of olesoxime. A total of 110 individuals with Type 2 or 3 SMA were included in the analyses. Test-retest reliability (intraclass-correlation coefficient in global impression-defined stable individuals), internal consistency (Cronbach’s alpha), convergent validity (Spearman rank order correlations with other measures), known-groups validity (analysis of covariance comparing Hammersmith Functional Motor Scale -defined groups), and ability to detect change (analysis of covariance comparing global impression-defined groups) were calculated. Strong evidence of test-retest reliability (intraclass-correlation coefficient = 0.93–0.95), internal consistency (Cronbach’s alpha = 0.89), convergent validity (Hammersmith Functional Motor Scale: rho = 0.87; forced vital capacity: rho = 0.61), known-groups validity (all p<0.0001), and ability to detect change (all p<0.001) were demonstrated. These results provide evidence of the MFM32’s measurement properties, supporting its use in longitudinal research in individuals with Type 2 and non-ambulant Type 3 SMA.

Quality of life in children and adolescents with Spinal Muscular Atrophy

INTRODUCTION

Quality of life (QoL) is a key aspect in the treatment of patients with Spinal Muscular Atrophy (SMA). International information regarding QoL in SMA is scarce, and is not available in our country.

OBJECTIVE

To characterize QoL in a sample of Chilean children and adolescents with SMA.

SUBJECTS AND METHOD

Observational, cross-sectional study. A general questionnaire and the PedsQLTM 3.0 Neuromuscular Module Inventory were applied to parents of children with SMA aged 2 to 18 years. It has three areas: Disease, Communication, and Family. A score > 60 was considered as good QoL, 30-60 as regular, and < 30 as low. MINITAB-17« software was used, considering signifi cant a p < 0.05 value.

RESULTS

We recruited 38 patients, with median age 8 years (2-18), 52.63% were male, and 17 (44.7%) with SMA I. All had genetic confirmation. The total score of QoL was 51.92 ± 17, representing 31% good, 55% regular, and 14% low. Regarding SMA I, it was 46.5 ± 15.2 and SMA II-III, 56.3 ± 17.4 (p = 0.071). Concerning the area of Disease, it was 53.83 ± 18.1, Family 48.6 ± 23.14, and Communication 33.3 (IQR: 0.0; 83.33). In this last area, children with SMA II-III, older than 6 years., with non-invasive ventilatory support, or living out of the metropolitan area had hig her scores, however, in multivariate analysis, only SMA type was significant, which explained 40,9% of the variation in the communication area score.

CONCLUSIONS

In this sample of SMA pediatric patients, the QoL was regular or good in most of them. The lowest area was communication, with a higher score in those children with higher motor function.

GARS-related disease in infantile spinal muscular atrophy: Implications for diagnosis and treatment

The majority of patients with spinal muscular atrophy (SMA) identified to date harbor a biallelic exonic deletion of SMN1. However, there have been reports of SMA-like disorders that are independent of SMN1, including those due to pathogenic variants in the glycyl-tRNA synthetase gene (GARS1). We report three unrelated patients with de novo variants in GARS1 that are associated with infantile-onset SMA (iSMA). Patients were ascertained during inpatient hospital evaluations for complications of neuropathy. Evaluations were completed as indicated for clinical care and management and informed consent for publication was obtained. One newly identified, disease-associated GARS1 variant, identified in two out of three patients, was analyzed by functional studies in yeast complementation assays. Genomic analyses by exome and/or gene panel and SMN1 copy number analysis of three patients identified two previously undescribed de novo missense variants in GARS1 and excluded SMN1 as the causative gene. Functional studies in yeast revealed that one of the de novo GARS1 variants results in a loss-of-function effect, consistent with other pathogenic GARS1 alleles. In sum, the patients' clinical presentation, assessments of previously identified GARS1 variants and functional assays in yeast suggest that the GARS1 variants described here cause iSMA. GARS1 variants have been previously associated with Charcot-Marie-Tooth disease (CMT2D) and distal SMA type V (dSMAV). Our findings expand the allelic heterogeneity of GARS-associated disease and support that severe early-onset SMA can be caused by variants in this gene. Distinguishing the SMA phenotype caused by SMN1 variants from that due to pathogenic variants in other genes such as GARS1 significantly alters approaches to treatment.

Neurofilament light chain in serum of adolescent and adult SMA patients under treatment with nusinersen

OBJECTIVE

To determine the diagnostic and monitoring value of serum neurofilament light chain (NfL) in spinal muscular atrophy (SMA).

METHODS

We measured serum NfL in 46 SMA patients at baseline and over 14 months of treatment with the antisense-oligonucleotide (ASO) nusinersen using the ultrasensitive single molecule array (Simoa) technology. Serum NfL levels of SMA patients were compared to controls and related to cerebrospinal fluid (CSF) NfL, blood-CSF barrier function quantified by the albumin blood/CSF ratio (Qalb) and motor scores (Hammersmith Functional Motor Scale Expanded, HFMSE; Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised, ALSFRS-R).

RESULTS

Serum NfL levels of SMA patients were in the range of controls (p = 0.316) and did not correlate with CSF NfL (ρ = 0.302, p = 0.142) or Qalb (ρ = - 0.160, p = 0.293). During therapy, serum NfL levels were relatively stable with notable concentration changes in single SMA patients, however, within the control range. Higher NfL levels were associated with worse motor performance in SMA (baseline: HFMSE ρ = - 0.330, p = 0.025, ALSFRS-R ρ = - 0.403, p = 0.005; after 10 months: HFMSE ρ = - 0.525, p = 0.008, ALSFRS-R ρ = - 0.537, p = 0.007), but changes in motor scores did not correlate with changes in serum NfL.

CONCLUSION

Diagnostic and monitoring performance of serum NfL measurement seems to differ between SMA subtypes. Unlike to SMA type 1, in adolescent and adult SMA type 2 and 3 patients, neurodegeneration is not reflected by increased NfL levels and short-term therapeutic effects cannot be observed. Long-term follow-up has to be performed to see if even low levels of NfL might be good prognostic markers.

Prospective and longitudinal natural history study of patients with Type 2 and 3 spinal muscular atrophy: Baseline data NatHis-SMA study

Spinal muscular atrophy (SMA) is a monogenic disorder caused by loss of function mutations in the survival motor neuron 1 gene, which results in a broad range of disease severity, from neonatal to adult onset. There is currently a concerted effort to define the natural history of the disease and develop outcome measures that accurately capture its complexity. As several therapeutic strategies are currently under investigation and both the FDA and EMA have recently approved the first medical treatment for SMA, there is a critical need to identify the right association of responsive outcome measures and biomarkers for individual patient follow-up. As an approved treatment becomes available, untreated patients will soon become rare, further intensifying the need for a rapid, prospective and longitudinal study of the natural history of SMA Type 2 and 3. Here we present the baseline assessments of 81 patients aged 2 to 30 years of which 19 are non-sitter SMA Type 2, 34 are sitter SMA Type 2, 9 non-ambulant SMA Type 3 and 19 ambulant SMA Type 3. Collecting these data at nine sites in France, Germany and Belgium established the feasibility of gathering consistent data from numerous and demanding assessments in a multicenter SMA study. Most assessments discriminated between the four groups well. This included the Motor Function Measure (MFM), pulmonary function testing, strength, electroneuromyography, muscle imaging and workspace volume. Additionally, all of the assessments showed good correlation with the MFM score. As the untreated patient population decreases, having reliable and valid multi-site data will be imperative for recruitment in clinical trials. The pending two-year study results will evaluate the sensitivity of the studied outcomes and biomarkers to disease progression.

Trial Registration: ClinicalTrials.gov (NCT02391831).

Cortical Activation Changes in Hirayama Disease After Anterior Cervical Decompression and Fusion

BACKGROUND

Spinal cord injury may cause cortical reconstruction. We, therefore explored the changes in cortical activation before and after anterior cervical decompression and fusion surgery in patients with Hirayama disease (HD).

METHODS

In total, 17 cases with HD underwent anterior cervical decompression and fusion surgery. Blood oxygenation level-dependent functional magnetic resonance imaging scan was performed preoperatively, 3 months, 6 months, and 1 year after surgery. Activated voxels were compared between both hands after adjusting for head motion, slice timing, spatial normalization, and image smoothing. Grip strength also was tested in both hands.

RESULTS

A retrospective review indicated that the grip strength of the asymptomatic hand was significantly stronger than the symptomatic hand at the time point before the surgery, 3 months after surgery, 6 months after surgery, and 1 year after surgery (P < 0.001). The grip strength of both symptomatic and asymptomatic hands continuously increased within 6 months after surgery (P < 0.05), but it stopped at 1 year after the surgery. The symptomatic limb tends to produce bilateral activation in the primary motor area (M1) during motor tasks. Both contralateral and ipsilateral M1 activation were stronger in symptomatic hand tasks preoperatively (P < 0.05). Both contralateral and ipsilateral activation in M1 during symptomatic hand tasks began to reduce after surgery, and statistical significance was observed 6 months after surgery (P < 0.05). Contralateral activation was relatively even over 6 months of the surgery (P > 0.05).

CONCLUSIONS

After surgery, pathologic reconstruction may have occurred in the primary motor cortex. Recovery of motor function in the symptomatic limb was accompanied by decreased ipsilateral and contralateral M1 activation, as well as symptom improvement. These findings suggested that postoperative cortical activation changes may reflect functional recovery in HD.

Detection of early nocturnal hypoventilation in neuromuscular disorders

Objective Nocturnal hypoventilation (NH) is a complication of respiratory involvement in neuromuscular disorders (NMD) that can evolve into symptomatic daytime hypercapnia if not treated proactively with non-invasive ventilation. This study aimed to assess whether NH can be detected in the absence of other signs of nocturnal altered gas exchange. Methods We performed nocturnal transcutaneous coupled (tc) pCO2/SpO2 monitoring in 46 consecutive cases of paediatric-onset NMD with a restrictive respiratory defect (forced vital capacity < 60%). Nocturnal hypoventilation was defined as tcPCO2 > 50 mmHg for > 25% of recorded time, and hypoxemia as tcSpO2 < 88% for > 5 minutes. Daytime symptoms and bicarbonate were recorded after overnight monitoring. Results Twenty-nine of 46 consecutive patients showed NH. Twenty-three patients did not have nocturnal hypoxemia and 18 were clinically asymptomatic. In 20 patients, PaCO2 in daytime blood samples was normal. Finally, 13/29 patients with NH had isolated nocturnal hypercapnia without nocturnal hypoxia, clinical NH symptoms, or daytime hypercapnia. Conclusions Paediatric patients with NMD can develop NH in the absence of clinical symptoms or significant nocturnal desaturation. Therefore, monitoring of NH should be included among nocturnal respiratory assessments of these patients as an additional tool to determine when to commence non-invasive ventilation.

Nusinersen versus Sham Control in Later-Onset Spinal Muscular Atrophy

BACKGROUND

Nusinersen is an antisense oligonucleotide drug that modulates pre-messenger RNA splicing of the survival motor neuron 2 ( SMN2) gene. It has been developed for the treatment of spinal muscular atrophy (SMA).

METHODS

We conducted a multicenter, double-blind, sham-controlled, phase 3 trial of nusinersen in 126 children with SMA who had symptom onset after 6 months of age. The children were randomly assigned, in a 2:1 ratio, to undergo intrathecal administration of nusinersen at a dose of 12 mg (nusinersen group) or a sham procedure (control group) on days 1, 29, 85, and 274. The primary end point was the least-squares mean change from baseline in the Hammersmith Functional Motor Scale-Expanded (HFMSE) score at 15 months of treatment; HFMSE scores range from 0 to 66, with higher scores indicating better motor function. Secondary end points included the percentage of children with a clinically meaningful increase from baseline in the HFMSE score (≥3 points), an outcome that indicates improvement in at least two motor skills.

RESULTS

In the prespecified interim analysis, there was a least-squares mean increase from baseline to month 15 in the HFMSE score in the nusinersen group (by 4.0 points) and a least-squares mean decrease in the control group (by -1.9 points), with a significant between-group difference favoring nusinersen (least-squares mean difference in change, 5.9 points; 95% confidence interval, 3.7 to 8.1; P<0.001). This result prompted early termination of the trial. Results of the final analysis were consistent with results of the interim analysis. In the final analysis, 57% of the children in the nusinersen group as compared with 26% in the control group had an increase from baseline to month 15 in the HFMSE score of at least 3 points (P<0.001), and the overall incidence of adverse events was similar in the nusinersen group and the control group (93% and 100%, respectively).

CONCLUSIONS

Among children with later-onset SMA, those who received nusinersen had significant and clinically meaningful improvement in motor function as compared with those in the control group. (Funded by Biogen and Ionis Pharmaceuticals; CHERISH ClinicalTrials.gov number, NCT02292537 .).

Motor Function Test Reliability During the NeuroNEXT Spinal Muscular Atrophy Infant Biomarker Study

BACKGROUND

The NeuroNEXT SMA Infant Biomarker Study, a two year, longitudinal, multi-center study of infants with SMA type 1 and healthy infants, presented a unique opportunity to assess multi-site rater reliability on three infant motor function tests (MFTs) commonly used to assess infants with SMA type 1.

OBJECTIVE

To determine the effect of prospective MFT rater training and the effect of rater experience on inter-rater and intra-rater reliability for the Test of Infant Motor Performance Screening Items (TIMPSI), the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) and the Alberta Infant Motor Scale (AIMS).

METHODS

Training was conducted utilizing a novel set of motor function test (MFT) videos to optimize accurate MFT administration and reliability for the study duration. Inter- and intra-rater reliability of scoring for the TIMPSI and inter-rater reliability of scoring for the CHOP INTEND and the AIMS was assessed using intraclass correlation coefficients (ICC). Effect of rater experience on reliability was examined using ICC. Agreement with 'expert' consensus scores was examined using Pearson's correlation coefficients.

RESULTS

Inter-rater reliability on all MFTs was good to excellent. Intra-rater reliability for the primary MFT, the TIMPSI, was excellent for the study duration. Agreement with 'expert' consensus was within predetermined limits (≥85%) after training. Evaluator experience with SMA and MFTs did not affect reliability.

CONCLUSIONS

Reliability of scores across evaluators was demonstrated for all three study MFTs and scores were reproducible on repeated administration. Evaluator experience had no effect on reliability.

Single-Dose Gene-Replacement Therapy for Spinal Muscular Atrophy

BACKGROUND

Spinal muscular atrophy type 1 (SMA1) is a progressive, monogenic motor neuron disease with an onset during infancy that results in failure to achieve motor milestones and in death or the need for mechanical ventilation by 2 years of age. We studied functional replacement of the mutated gene encoding survival motor neuron 1 (SMN1) in this disease.

METHODS

Fifteen patients with SMA1 received a single dose of intravenous adeno-associated virus serotype 9 carrying SMN complementary DNA encoding the missing SMN protein. Three of the patients received a low dose (6.7×10¹³ vg per kilogram of body weight), and 12 received a high dose (2.0×10¹⁴ vg per kilogram). The primary outcome was safety. The secondary outcome was the time until death or the need for permanent ventilatory assistance. In exploratory analyses, we compared scores on the CHOP INTEND (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders) scale of motor function (ranging from 0 to 64, with higher scores indicating better function) in the two cohorts and motor milestones in the high-dose cohort with scores in studies of the natural history of the disease (historical cohorts).

RESULTS

As of the data cutoff on August 7, 2017, all 15 patients were alive and event-free at 20 months of age, as compared with a rate of survival of 8% in a historical cohort. In the high-dose cohort, a rapid increase from baseline in the score on the CHOP INTEND scale followed gene delivery, with an increase of 9.8 points at 1 month and 15.4 points at 3 months, as compared with a decline in this score in a historical cohort. Of the 12 patients who had received the high dose, 11 sat unassisted, 9 rolled over, 11 fed orally and could speak, and 2 walked independently. Elevated serum aminotransferase levels occurred in 4 patients and were attenuated by prednisolone.

CONCLUSIONS

In patients with SMA1, a single intravenous infusion of adeno-associated viral vector containing DNA coding for SMN resulted in longer survival, superior achievement of motor milestones, and better motor function than in historical cohorts. Further studies are necessary to confirm the safety and efficacy of this gene therapy. (Funded by AveXis and others; ClinicalTrials.gov number, NCT02122952 .).

Nusinersen versus Sham Control in Infantile-Onset Spinal Muscular Atrophy

BACKGROUND

Spinal muscular atrophy is an autosomal recessive neuromuscular disorder that is caused by an insufficient level of survival motor neuron (SMN) protein. Nusinersen is an antisense oligonucleotide drug that modifies pre-messenger RNA splicing of the SMN2 gene and thus promotes increased production of full-length SMN protein.

METHODS

We conducted a randomized, double-blind, sham-controlled, phase 3 efficacy and safety trial of nusinersen in infants with spinal muscular atrophy. The primary end points were a motor-milestone response (defined according to results on the Hammersmith Infant Neurological Examination) and event-free survival (time to death or the use of permanent assisted ventilation). Secondary end points included overall survival and subgroup analyses of event-free survival according to disease duration at screening. Only the first primary end point was tested in a prespecified interim analysis. To control the overall type I error rate at 0.05, a hierarchical testing strategy was used for the second primary end point and the secondary end points in the final analysis.

RESULTS

In the interim analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (21 of 51 infants [41%] vs. 0 of 27 [0%], P<0.001), and this result prompted early termination of the trial. In the final analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (37 of 73 infants [51%] vs. 0 of 37 [0%]), and the likelihood of event-free survival was higher in the nusinersen group than in the control group (hazard ratio for death or the use of permanent assisted ventilation, 0.53; P=0.005). The likelihood of overall survival was higher in the nusinersen group than in the control group (hazard ratio for death, 0.37; P=0.004), and infants with a shorter disease duration at screening were more likely than those with a longer disease duration to benefit from nusinersen. The incidence and severity of adverse events were similar in the two groups.

CONCLUSIONS

Among infants with spinal muscular atrophy, those who received nusinersen were more likely to be alive and have improvements in motor function than those in the control group. Early treatment may be necessary to maximize the benefit of the drug. (Funded by Biogen and Ionis Pharmaceuticals; ENDEAR ClinicalTrials.gov number, NCT02193074 .).

Muscle-Bone Interactions in Pediatric Bone Diseases

PURPOSE

Here, we review the skeletal effects of pediatric muscle disorders as well as muscle impairment in pediatric bone disorders.

RECENT FINDINGS

When starting in utero, muscle disorders can lead to congenital multiple contractures. Pediatric-onset muscle weakness such as cerebral palsy, Duchenne muscular dystrophy, spinal muscular atrophy, or spina bifida typically are associated with small diameter of long-bone shafts, low density of metaphyseal bone, and increased fracture incidence in the lower extremities, in particular, the distal femur. Primary bone diseases can affect muscles through generic mechanisms, such as decreased physical activity or in disease-specific ways. For example, the collagen defect underlying the bone fragility of osteogenesis imperfecta may also affect muscle force generation or transmission. Transforming growth factor beta released from bone in Camurati Engelman disease may decrease muscle function.

FUTURE DIRECTIONS

Considering muscle-bone interactions does not only contribute to the understanding of musculoskeletal disorders but also can identify new targets for therapeutic interventions.

Relationships between long-term observations of motor milestones and genotype analysis results in childhood-onset Japanese spinal muscular atrophy patients

AIM

To clarify the long-term natural history of SMA in Japanese patients by investigating the peak motor milestones of cases 7months through 57years of age, in efforts to contribute to evaluating outcomes of new therapeutic interventions.

METHODS

We sub-classified 112 SMA type I-III cases into type Ia, type Ib, type IIa, type IIb, type IIIa and type IIIb, according to peak motor milestone achieved, and analyzed the SMN1, SMN2 and NAIP genes in relation to clinical subtypes.

RESULTS

In type I cases, there was a significant difference (p<0.0001), depending on whether or not head control was obtained, in the time of ventilation support being required. In type II cases as well, the time at which the ability to maintain the sitting position independently was lost also differed significantly (p<0.01) between those acquiring the ability to sit unaided within eight months after birth and those acquiring this ability after eight months of age. In type III cases, being able versus unable to climb stairs was associated with a significant difference (p=0.02) in the median time until loss of walking independently. Positive correlations were also seen between copy numbers and the clinical severity of SMA.

CONCLUSION

Our long-term results show peak motor milestone evaluations distinguishing between subtypes to be useful not only as outcome measures for assessing treatment efficacy in clinical trials but also for predicting the clinical courses of Japanese SMA patients.

[Non-invasive positive pressure ventilation during the management of severe spinal muscular atrophy type I]

Patients with spinal muscular atrophy type Ⅰ (SMA Ⅰ) with the onset before the age of 3 months are considered as severe form of SMA Ⅰ (severe SMA Ⅰ) and have poor prognosis. Here, we report the efficacy of non-invasive positive pressure ventilation (NPPV) in a patient with severe SMA Ⅰ. She was born with generalized hypotonia and feeding difficulties, and had SMN1 gene mutations (the deletion of exons 7 and 8). At 1 month of age, she was intubated because of respiratory failure due to a respiratory tract infection, and extubation proved difficult. Her parents decided that NPPV and a mechanical in-exsufflator (MI-E) should be used for respiratory management rather than a tracheotomy. The NPPV improved her peripheral coldness, cold sweats, chest wall movement, and heart rate and enabled her to sleep well. At 1 year and 2 months, chest computed tomography revealed mild pneumonia and did not show any atelectasis. The NPPV facilitated discharge, and the patient had a good quality of life (QOL) from the point of view of voice production, the ability to move easily, the simplicity of bathing, and the low level of discomfort she experienced. However, she suffered repeated episodes of aspiration pneumonia and airway obstruction (by sputum) after 11 months of age. Thereafter, she required continuous NPPV and high-span inspiratory positive airway pressure (21 cmH2O). At 1 year and 4 months, she died of respiratory failure at home. As her bulbar weakness worsened, respiratory management with NPPV became difficult. However, the long-term use of NPPV together with high-span positive inspiratory pressure plus positive end-expiratory pressure, and a high-pressure MI-E at an early age might improve respiratory management outcomes and patient prognosis. In our case, NPPV was effective at improving ventilation and preventing atelectasis and helped to provide the patient with a good QOL.

Disease impact on general well-being and therapeutic expectations of European Type II and Type III spinal muscular atrophy patients

Spinal muscular atrophy (SMA) is a neurodegenerative disorder showing a broad clinical spectrum and no cure to date. To design and select evaluation criteria for the potential assessment of drugs currently being developed, the patient's perspective is critical. A survey, aiming to obtain a view on the current clinical state of European Type II and Type III SMA patients, the impact of this situation on their quality of life and their expectations regarding clinical development, was carried out by SMA-Europe member organizations in July 2015. A questionnaire was set up, translated into 8 European languages and sent out directly via electronic mailing to the targeted SMA patient population by the respective European patient organizations. We were able to collect 822 valid replies in less than two weeks. The questionnaire captured the current abilities of the respondents, their perception of the disease burden which appeared very similar across Europe despite some regional variations in care. According to the great majority of the respondents, stabilization of their current clinical state would represent a therapeutic progress for a compelling majority of the respondents to the questionnaire.

Feasibility of Using Microsoft Kinect to Assess Upper Limb Movement in Type III Spinal Muscular Atrophy Patients

Although functional rating scales are being used increasingly as primary outcome measures in spinal muscular atrophy (SMA), sensitive and objective assessment of early-stage disease progression and drug efficacy remains challenging. We have developed a game based on the Microsoft Kinect sensor, specifically designed to measure active upper limb movement. An explorative study was conducted to determine the feasibility of this new tool in 18 ambulant SMA type III patients and 19 age- and gender-matched healthy controls. Upper limb movement was analysed elaborately through derived features such as elbow flexion and extension angles, arm lifting angle, velocity and acceleration. No significant differences were found in the active range of motion between ambulant SMA type III patients and controls. Hand velocity was found to be different but further validation is necessary. This study presents an important step in the process of designing and handling digital biomarkers as complementary outcome measures for clinical trials.

Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings.The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed.Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups.Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles.

Monomelic amyotrophy with proximal upper limb involvement: a case report

BACKGROUND

Monomelic amyotrophy is an uncommon, benign, unilateral disorder of the lower motor neurons, affecting predominantly the hand and forearm muscles. Proximal involvement of the arm and shoulder muscles is an unusual presentation that has been rarely reported in the literature.

CASE PRESENTATION

A 28-year-old white man presented with insidious-onset, slowly progressive, unilateral weakness and atrophy of his left shoulder girdle and deltoid muscles. A neurological examination revealed weakness and atrophy in his left deltoid, infraspinatus and supraspinatus muscles. Electromyography demonstrated an active and chronic neurogenic pattern affecting his left C5 and C6 myotomes; magnetic resonance imaging of his cervical spine was normal. He did well with conservative treatment.

CONCLUSIONS

Upper limb proximal form of monomelic amyotrophy is a rare clinical entity with a wide differential diagnosis. Physicians, especially neurologists, should be familiar with this benign condition to avoid inappropriately labeling patients as having amyotrophic lateral sclerosis and other disorders with less favorable outcomes.

Distally pronounced infantile spinal muscular atrophy with severe axonal and demyelinating neuropathy associated with the S230L mutation of SMN1

Two Croatian siblings with atypical clinical findings in the presence of SMN1 gene mutations are reported. The girl presented with delayed motor development and weakness in hands and feet in her first year of life. She never stood or walked and developed scoliosis and joint contractures during childhood. Her hands and feet were non-functional when last seen at age 14 years. Her 4-year-old brother was more severely affected and had a clinical picture resembling infantile spinal muscular atrophy (SMA) type 1. He also showed unusual distally pronounced weakness and facial weakness. Both patients had no sensory deficits but gave evidence of a mixed axonal and demyelinating neuropathy with pronounced slowing in the distal nerve segments. Unexpectedly, both siblings showed a compound heterozygous SMN1 mutation (heterozygous deletion and missense mutation c.689C > T; p.S230L), thus confirming infantile SMA. In addition, next generation sequencing of 52 genes for hereditary neuropathies revealed a heterozygous missense mutation c.505T > C; p.Y169H in the SH3TC2 gene that was transmitted by the healthy father. Our observations widen the phenotypic consequences of SMN1 gene mutations and support the notion to look for additional genetic factors which may modify the clinical picture in atypical cases.

[Hirayama disease: report of four Tunisian cases and review of literature]

Nous rapportons les aspects cliniques et électriques de la maladie de Hirayama en Tunisie à travers une série de quatre observations diagnostiquées au service de neurologie Sahloul. Il s'agit de quatre femmes. L’âge moyen était 30,25 ans avec des extrêmes de 27 et 37 ans. Une patiente avait un antécédent de traumatisme cervical, trois avaient une profession favorisant la position prolongée du rachis cervical en flexion. Un déficit moteur distal et une amyotrophie de la main et de l'avant bras droits d'installation progressive étaient observés dans tous les cas. Il n'avait ni des troubles sensitifs objectifs ni de modification des reflexes ostéotendineux et cutanés. L'EMG montrait une dénervation motrice dans le territoire des muscles dépendants des racines C7, C8, et D1. L'IRM cervicale était sans anomalie dans tous les cas. L’évolution était marquée par la bilatéralisation de la symptomatologie chez une patiente et une stabilisation clinique chez les autres. Ainsi, les aspects cliniques et électriques de la maladie de Hirayama dans cette série tunisienne sont comparables à ceux rapportés dans la littérature en dehors d'une atteinte strictement féminine.

Upper limb evaluation and one-year follow up of non-ambulant patients with spinal muscular atrophy: an observational multicenter trial

Assessment of the upper limb strength in non-ambulant neuromuscular patients remains challenging. Although potential outcome measures have been reported, longitudinal data demonstrating sensitivity to clinical evolution in spinal muscular atrophy patients are critically lacking. Our study recruited 23 non-ambulant patients, 16 patients (males/females = 6/10; median age 15.4 years with a range from 10.7 to 31.1 years) with spinal muscular atrophy type II and 7 patients (males/females = 2/5; median age 19.9 years with a range from 8.3 to 29.9 years) with type III. The Brooke functional score was on median 3 with a range from 2 to 6. The average total vital capacity was 46%, and seven patients required non-invasive ventilation at night. Patients were assessed at baseline, 6 months, and 1 year using the Motor Function Measure and innovative devices MyoGrip, MyoPinch, and MoviPlate, which assess handgrip strength, key pinch strength, and hand/finger extension-flexion function, respectively. The study demonstrated the feasibility and reliability of these measures for all patients, and sensitivity to negative changes after the age of 14 years. The younger patients showed an increase of the distal force in the follow-up period. The distal force measurements and function were correlated to different functional scales. These data represent an important step in the process of validating these devices as potential outcome measures for future clinical trials.

[Cervical flexion F-waves in the patients with Hirayama diseases]

OBJECTIVE

To identify whether there is significant changes between the cervical neutral F-waves and cervical flexion F-waves in the patients with Hirayama disease.

METHODS

This study was performed on 25 normal subjects and 22 male patients with identified Hirayama disease (age: 15 to 44 years; height: 165 to 183 cm; duration: 6 to 240 months) between May 2010 and March 2014. Both cervical flexion F-wave (cervical flexion 45 °, 30 minutes) and conventional F-waves to median nerve stimulation and to ulnar nerve stimulation were performed in all subjects bilaterally.

RESULTS

were analyzed by t-test or Fisher exact probability.

RESULTS

In the normal subjects, all measurements of the bilateral F-waves didn't have any difference between the cervical flexion position and the cervical neutral position. On the cervical neutral position, the persistence (t = 5.209, P = 0.000), average latencies (t = 4.731, P = 0.022) and minimal latencies (t = 23.843, P = 0.006) of ulnar F-wave on the symptomatic heavier side from the patients with identified Hirayama disease were significantly lower or longer than those from the normal subjects, and the repeat F-waves were found in 3 patients (13.6%). On the symptomatic lighter side, the ulnar F-waves only had lower persistence (t = 22.306, P = 0.001) along with 5 repeat F-waves. Only lower persistence were found in the median F-wave on the both side (higher side t = 23.696, P = 0.000; lighter side t = 23.998, P = 0.000), along with 5 (22.7%) repeat F-waves on the symptomatic heavier side and 6 (27.3%) ones on the symptomatic lighter side. After cervical flexion maintaining 30 minutes, the increased maximal amplitudes (t = -2.552, P = 0.019), average amplitudes (t = -3.322, P = 0.003), duration (t = -3.323, P = 0.00), persistence (t = -2.604, P = 0.017) and frequency of repeat F-waves (9/22, 41%) (P = 0.044) were found on the symptomatic heavier side of ulnar F-wave, and 5 of 10 absent ulnar F-wave on the cervical neutral position were also recover. The median F-wave on the symptomatic heavier side mainly had increased maximal amplitude (t = -3.847, P = 0.001), average amplitudes (t = -2.188, P = 0.040) and persistence (t = -2.421, P = 0.025), and 1 of 6 absent median F-wave on the cervical neutral position were also recover after cervical flexion.

CONCLUSION

The cervical flexion F-waves have significant regular changes compared to the cervical neutral F-waves in patients with Hirayama diseases, especially maximal and average amplitudes of F-waves.

Vitamin D intake is inadequate in spinal muscular atrophy type I cohort: correlations with bone health

Children with type I spinal muscular atrophy commonly demonstrate reduced bone mineral density. Our objectives were to evaluate and assess adequacy of vitamin D intake, serum levels, and association with bone mineral density. Assessments were completed using 3-day food records and dual energy x-ray absorptiometry scans. The spinal muscular atrophy type I cohort included 22 males and 18 females (N = 40), with a mean age of 18.6 months. Data collection occurred from 2001 to 2011. Seventy-five percent of patients had inadequate intake of vitamin D at the initial visit. Using mixed-effects analyses, vitamin D and calcium intakes correlated positively with bone mineral density (r = 0.31 and r = 0.53, respectively). Increased vitamin D and calcium consumption were associated with an increase in bone mineral density (P = .04 and P = .01, respectively). Vitamin D intake correlated positively with serum levels (r = 0.65). Further study is needed to determine optimal intakes of vitamin D and calcium in the spinal muscular atrophy type I population.

Nosology of juvenile muscular atrophy of distal upper extremity: from monomelic amyotrophy to Hirayama disease--Indian perspective

Since its original description by Keizo Hirayama in 1959, "juvenile muscular atrophy of the unilateral upper extremity" has been described under many nomenclatures from the east. Hirayama disease (HD), also interchangeably referred to as monomelic amyotrophy, has been more frequently recognised in the west only in the last two decades. HD presents in adolescence and young adulthood with insidious onset unilateral or bilateral asymmetric atrophy of hand and forearm with sparing of brachioradialis giving the characteristic appearance of oblique amyotrophy. Symmetrically bilateral disease has also been recognized. Believed to be a cervical flexion myelopathy, HD differs from motor neuron diseases because of its nonprogressive course and pathologic findings of chronic microcirculatory changes in the lower cervical cord. Electromyography shows features of acute and/or chronic denervation in C7, C8, and T1 myotomes in clinically affected limb and sometimes also in clinically unaffected contralateral limb. Dynamic forward displacement of dura in flexion causes asymmetric flattening of lower cervical cord. While dynamic contrast magnetic resonance imaging is diagnostic, routine study has high predictive value. There is a need to lump all the nomenclatures under the rubric of HD as prognosis in this condition is benign and prompt diagnosis is important to institute early collar therapy.

Mutation in E1, the ubiquitin activating enzyme, reduces Drosophila lifespan and results in motor impairment

Neurodegenerative diseases cause tremendous suffering for those afflicted and their families. Many of these diseases involve accumulation of mis-folded or aggregated proteins thought to play a causal role in disease pathology. Ubiquitinated proteins are often found in these protein aggregates, and the aggregates themselves have been shown to inhibit the activity of the proteasome. These and other alterations in the Ubiquitin Pathway observed in neurodegenerative diseases have led to the question of whether impairment of the Ubiquitin Pathway on its own can increase mortality or if ongoing neurodegeneration alters Ubiquitin Pathway function as a side-effect. To address the role of the Ubiquitin Pathway in vivo, we studied loss-of-function mutations in the Drosophila Ubiquitin Activating Enzyme, Uba1 or E1, the most upstream enzyme in the Ubiquitin Pathway. Loss of only one functional copy of E1 caused a significant reduction in adult lifespan. Rare homozygous hypomorphic E1 mutants reached adulthood. These mutants exhibited further reduced lifespan and showed inappropriate Ras activation in the brain. Removing just one functional copy of Ras restored the lifespan of heterozygous E1 mutants to that of wild-type flies and increased the survival of homozygous E1 mutants. E1 homozygous mutants also showed severe motor impairment. Our findings suggest that processes that impair the Ubiquitin Pathway are sufficient to cause early mortality. Reduced lifespan and motor impairment are seen in the human disease X-linked Infantile Spinal Muscular Atrophy, which is associated with mutation in human E1 warranting further analysis of these mutants as a potential animal model for study of this disease.

Observational study of caloric and nutrient intake, bone density, and body composition in infants and children with spinal muscular atrophy type I

Clinical experience supports a critical role for nutrition in patients with spinal muscular atrophy (SMA). Three-day dietary intake records were analyzed for 156 visits in 47 SMA type I patients, 25 males and 22 females, ages 1month to 13years (median 9.8months) and compared to dietary reference intakes for gender and age along with anthropometric measures and dual-energy X-ray absorptiometry (DEXA) data. Using standardized growth curves, twelve patients met criteria for failure to thrive (FTT) with weight for age <3rd percentile; eight met criteria based on weight for height. Percentage of body fat mass was not correlated with weight for height and weight for age across percentile categories. DEXA analysis further demonstrated that SMA type I children have higher fat mass and lower fat free mass than healthy peers (p<0.001). DEXA and dietary analysis indicates a strong correlation with magnesium intake and bone mineral density (r=0.65, p<0.001). Average caloric intake for 1-3years old was 68.8±15.8kcal/kg - 67% of peers' recommended intake. Children with SMA type I may have lower caloric requirements than healthy age-matched peers, increasing risk for over and undernourished states and deficiencies of critical nutrients. Standardized growth charts may overestimate FTT status in SMA type I.

[Questionnaire survey conducted on the parents of patients with spinal muscular atrophy type 1 in Japan regarding switch devices, language development, upper extremity function and QOL]

OBJECTIVE

As information required to rehabilitate, we aimed to clarify the use of switch devices, language development, upper extremity function, and quality of life (QOL) in patients with spinal muscular atrophy (SMA) type 1 in Japan.

METHODS

A questionnaire survey was conducted on the parents of these patients.

RESULTS

A total of 48 completed questionnaires were collected. The median age of patients with SMA type 1 was 8 years (range, 13 months to 27 years). The patients used a switch device were 46.5%. Their language development was delayed, and their voluntary movement in the distal upper extremities was relatively retained. In QOL, parents' labor and burden for the care of patients were high.

CONCLUSIONS

It is necessary to provide specialist support that contributes to the spread of communication devices, which improve their motor function, language development and overall QOL.

Prospective cohort study of spinal muscular atrophy types 2 and 3

OBJECTIVE

To characterize the natural history of spinal muscular atrophy type 2 and type 3 (SMA 2/3) beyond 1 year and to report data on clinical and biological outcomes for use in trial planning.

METHODS

We conducted a prospective observational cohort study of 79 children and young adults with SMA 2/3 who participated in evaluations for up to 48 months. Clinically, we evaluated motor and pulmonary function, quality of life, and muscle strength. We also measured SMN2 copy number, hematologic and biochemical profiles, muscle mass by dual x-ray absorptiometry (DXA), and the compound motor action potential (CMAP) in a hand muscle. Data were analyzed for associations between clinical and biological/laboratory characteristics cross-sectionally, and for change over time in outcomes using all available data.

RESULTS

In cross-sectional analyses, certain biological measures (specifically, CMAP, DXA fat-free mass index, and SMN2 copy number) and muscle strength measures were associated with motor function. Motor and pulmonary function declined over time, particularly at time points beyond 12 months of follow-up.

CONCLUSION

The intermediate and mild phenotypes of SMA show slow functional declines when observation periods exceed 1 year. Whole body muscle mass, hand muscle compound motor action potentials, and muscle strength are associated with clinical measures of motor function. The data from this study will be useful for clinical trial planning and suggest that CMAP and DXA warrant further evaluation as potential biomarkers.

[A case of spinal muscular atrophy type 0 in Japan]

The patient was a 2-month-old female infant born at 41 weeks and 2 days of gestation presenting multiple arthrogryposis, severe muscle hypotonia and respiratory distress with difficulty in feeding. She suffered from repeated complications with aspiration pneumonia. On admission to our hospital, she exhibited fasciculation and absence of deep tendon reflexes. Examination of the motor nerve conduction velocity (MCV) revealed no muscle contraction. Deletions of the SMN and NAIP genes were noted. Based on severe clinical course and disease development in utero, she was given a diagnosis of spinal muscular atrophy (SMA) type 0 (very severe type). Arthrogryposis and disappearance of MCV are exclusion criteria for SMA. However, the clinical course of the infant was very severe and included such exclusion items. Consequently, when an infant presents muscle hypotonia and respiratory distress, SMA must be considered as one of the differential diagnoses, even though arthrogryposis is an exclusion criterion for SMA. We discuss this case in relation to the few extant reports on SMA type 0 in Japanese infants in the literature.

Neuroelectrophysiological characteristics of Hirayama disease: report of 14 cases

BACKGROUND

Hirayama disease is a juvenile muscular atrophy of the distal upper extremities and affects mainly young males. The present study aimed to investigate the neuroelectrophysiological characteristics of Hirayama disease.

METHODS

We retrospectively analyzed the neural conduction velocity (NCV) parameters and needle-electrode electromyograms (EMG) of 14 patients with Hirayama disease. According to the clinical features of the patients, NCV was performed on affected upper-limb including median nerves and ulnar nerves, while EMG was selectively performed on upper and lower extremities, sternocleidomast and thoracic paraspinal muscles.

RESULTS

The median nerves of all affected upper limbs of patients with Hirayama disease had normal conduction velocities and compound motor action potentials (CMAPs). The ulnar nerves of all affected upper limbs also had normal conduction velocities. Of the 16 measured ulnar nerves of the affected upper limbs, eight had normal CMAPS, while the other eight showed CMAPs below the normal value by < 20%. All patients had neurogenic injury on the affected side in muscles innervated by anterior horn cells at the lower cervical region (C7-8, T1). Four patients had unilateral upper-limb muscle neurogenic injury on the affected side. Seven patients had bilateral upper-limb muscle neurogenic injury, while only two patients experienced bilateral upper-limb muscle atrophy/weakness. The other three patients showed extensive neurogenic injury (unilateral upper-limb muscle atrophy/weakness in one patient, bilateral symptoms in the other two patients).

CONCLUSIONS

Electromyographic examination showed that the majority of Hirayama disease patients exhibited characteristic segmental injury in the anterior horn of the lower cervical region, while a few patients exhibited extensive neurogenic injury. These data suggest that the actual influence of Hirayama disease may be more extensive than indicated by the clinical presentations.

A clinical neurophysiology study of Hirayama disease

BACKGROUND

Hirayama disease is a rare disease characterized by juvenile-onset of asymmetric amyotrophy, of which etiology has not been clarified. The aim of our study was to investigate the clinical and neurophysiologic characteristics of Hirayama disease.

METHODS

Neurophysiological tests, including nerve conduction studies (NCS), F-wave and routine electromyography (EMG), were performed in seventy-three patients with Hirayama disease. EMG was selectively performed on upper and lower extremities, sternocleidomast and thoracic paravertebral muscles according to the clinical features of the patients.

RESULTS

Abnormal NCS parameters, including decreased compound muscle action potentials or delayed distal motor latency, were found in 34.2% (25/73) and 12.3% (9/73) of the patients, respectively. A total of 24.6% (18/73) of the patients showed decreased F-wave frequency. EMG demonstrated the presence of neurogenic lesions in all patients with spontaneous potentials, prolonged duration or augmentation of amplitude in motor unit potentials (MUPs), or a single pattern of MUP recruitment. About 17.8% (13/73) of the patients showed neurogenic lesions, mostly in the C7-8 level of the cervical cord, only in the upper extremity of affected side, whereas 35.6% (26/73) of the patients possessed lesions in the upper extremities bilaterally. A total of 46.6% (34/73) of patients exhibited abnormalities in the lower extremities, sterno- cleidomast or thoracic paravertebral muscle. Changes in motor NCS were significantly correlated with muscle strength.

CONCLUSIONS

EMG detects diffused subclinical neurogenic lesion in a high proportion of patients with Hirayama disease. Results of our study challenge the hypothesis that Hirayama disease is a type of cervical myelopathy.