Physical therapy services received by individuals with spinal muscular atrophy (SMA)

Diving into progress: a review on current therapeutic advancements in spinal muscular atrophy

Spinal muscular atrophy (SMA) is an uncommon disorder associated with genes characterized by the gradual weakening and deterioration of muscles, often leading to substantial disability and premature mortality. Over the past decade, remarkable strides have been made in the field of SMA therapeutics, revolutionizing the landscape of patient care. One pivotal advancement is the development of gene-targeted therapies, such as nusinersen, onasemnogene abeparvovec and risdiplam which have demonstrated unprecedented efficacy in slowing disease progression. These therapies aim to address the root cause of SMA by targeting the survival motor neuron (SMN) gene, effectively restoring deficient SMN protein levels. The advent of these innovative approaches has transformed the prognosis for many SMA patients, offering a glimmer of hope where there was once limited therapeutic recourse. Furthermore, the emergence of small molecule compounds and RNA-targeting strategies has expanded the therapeutic arsenal against SMA. These novel interventions exhibit diverse mechanisms of action, including SMN protein stabilization and modulation of RNA splicing, showcasing the multifaceted nature of SMA treatment research. Collective efforts of pharmaceutical industries, research centers, and patient advocacy groups have played an important role in expediting the translation of scientific discoveries into visible clinical benefits. This review not only highlights the remarkable progress achieved in SMA therapeutics but also generates the ray of hope for the ongoing efforts required to enhance accessibility, optimize treatment strategies, rehabilitation (care and therapies) and ultimately pave the way for an improved quality of life for individuals affected by SMA.

Cognitive impairment in Chinese adult patients with type III spinal muscular atrophy without disease-modifying treatment

Objective

Spinal muscular atrophy (SMA) is a neurodegenerative disorder characterized by the degeneration of motor neurons in the spinal cord. It remains uncertain whether the cognitive performance of adult patients with SMA is impaired. The objective of this study was to assess the cognitive profile of adult Chinese patients with SMA and the association between clinical features and cognitive ability, particularly executive function.

Methods

This cross-sectional study included 22 untreated adult patients with type III SMA and 20 healthy subjects. The following variables were assessed: general intelligence, memory, attention, language, executive function, depression, anxiety, and other demographic and clinical parameters. In addition, physical function was evaluated using the Hammersmith Functional Motor Scale Expanded (HFMSE), the Revised Upper Limb Module (RULM), and the 6-Minute Walk Test (6MWT).

Results

SMA patients had lower scores than healthy subjects in the Verbal Fluency Test, Stroop effect, Total Errors, Perseverative Responses, Perseverative Errors, and Non-perseverative Errors in the Wisconsin Card Sorting Test, showing impaired abilities of SMA patients in executive function. In the Attention Network Test (ANT), the results indicated that the SMA patients also had selective deficits in their executive control networks. Ambulant patients had better executive function test performance than non-ambulant ones. Compromised executive abilities in patients with SMA were correlated with a younger age at onset, poorer motor function, and higher levels of anxiety and depression.

Conclusion

Our study presented the distribution of cognitive impairment in a Chinese cohort with SMA. Patients with type III SMA showed selective deficits in executive function, which may be associated with disease severity, physical impairment, depression and anxiety. Future cognitive studies, accounting for motor and emotional impairment, are needed to evaluate if executive impairment is driven by specific brain changes or by those confounding factors.

Spinal muscular atrophy: health related quality of life and burden to parents

Objective: To analyze the relationship between the quality of life (QoL) of children and adolescents with Spinal Muscular Atrophy (SMA) and the burden on their parents. Methods: A cross-sectional study with 64 parents (53 women) of children and adolescents with SMA was conducted through an online questionnaire. Health-related QoL of children and adolescents with SMA according to the parents was evaluated using PedsQL 4.0, and Zarit Burden Interview (ZBI) was used to assess the burden on the parents. Correlation and association tests evaluated the relationship between the QoL of individuals with SMA, the burden on parents, and the factors related to these variables. Results: Parents aged between 21 and 52 years (mean 36.9 ± 7.3 years) were evaluated, of which 62.5% had a moderate burden. PedsQL 4.0 total score ranged from 19.6 to 93.5 points, and ZBI from 8 to 57 points. A negative correlation was observed between these variables (r = -0.4; p = 0.001). Furthermore, ZBI scores were related to the education level of parents (rho = 0.3; p = 0.02), changes in emotional or psychological health caused by SMA diagnosis in parents (rho = -0.4; p = 0.004), and family income (rho = 0.3; p = 0.03). Conclusion: Health-related QoL in children and adolescents with SMA was related to the burden on their parents. This highlights the importance of therapeutic programs focused on individuals with SMA, as well as the needs of their parents.

Management of Spinal Muscular Atrophy in the Adult Population

Spinal muscular atrophy (SMA) is a group of neurodegenerative disorders resulting from the loss of spinal motor neurons. 95% of patients share a pathogenic mechanism of loss of survival motor neuron (SMN) 1 protein expression due to homozygous deletions or other mutations of the SMN1 gene, with the different phenotypes influenced by variable copy numbers of the SMN2 gene. Advances in supportive care, disease modifying treatment and novel gene therapies have led to an increase in the prevalence of SMA, with a third of SMA patients now represented by adults. Despite the growing number of adult patients, consensus on the management of SMA has focused primarily on the pediatric population. As the disease burden is vastly different in adult SMA, an approach to treatment must be tailored to their unique needs. This review will focus on the management of the adult SMA patient as they age and will discuss proper transition of care from a pediatric to adult center, including the need for continued monitoring for osteoporosis, scoliosis, malnutrition, and declining mobility and functioning. As in the pediatric population, multidisciplinary care remains the best approach to the management of adult SMA. Novel and emerging therapies such as nusinersen and risdiplam provide hope for these patients, though these medications are of uncertain efficacy in this population and require additional study.

Daily Outpatient Physical Therapy for a Toddler With a Neurodegenerative Disease: A Case Report

PURPOSE

This case report highlights the potential value of delivering a high-dose physical therapy (PT) intervention for a child with a neurodegenerative disease. We include developmental outcomes for a 23-month-old toddler with biallelic TBCD gene mutations following daily outpatient PT.

SUMMARY OF KEY POINTS

The child had clinical improvements in gross and fine motor, cognition, expressive and receptive language, socioemotional, and adaptive behavior function as determined through Goal Attainment Scaling, Gross Motor Function Measure, and Bayley Scales of Infant and Toddler Development following daily PT intervention.

STATEMENT OF CONCLUSION AND RECOMMENDATIONS FOR CLINICAL PRACTICE

High-dose outpatient PT may be beneficial for a child with a neurodegenerative disease at some time frames. In selected cases, if the neurodegenerative disease slowly progresses, high-dose PT may be a treatment option to promote motor change.

Filling the gaps in knowledge translation: Physical therapy recommendations for individuals with spinal muscular atrophy compared to standard of care guidelines

This study describes the current landscape of physical therapy practice recommendations in the United States for children with spinal muscular atrophy (SMA) and their relationship to current SMA standard of care (SMA-SOC) guidelines. Pediatric physical therapists were surveyed to determine their knowledge of SMA-SOC guidelines, and the type, duration and frequency of intervention they recommend for children with SMA, as well as perceived barriers and facilitators to progress in physical therapy. Physical therapists recommend five key intervention areas for individuals with SMA; however discrepancies exist between the SOC recommended intervention parameters and respondents' reported frequency and duration of recommendations. After individuals with SMA initiated disease modifying pharmacotherapies, a majority of physical therapist respondents recommended increases in both frequency and duration of interventions. Nearly all respondents reported that familiarity with SOC guidelines was beneficial to their practice. The primary facilitator to progress was parent/caregiver support, while the primary barrier was limited access to resources. Variation in practice exists regarding care for those with SMA, particularly in the areas of frequency and duration of specific interventions. These findings can guide educational initiatives, identify future research needs and further inform SMA-SOC and best-practice rehabilitation management.

Current and emerging therapies for Duchenne muscular dystrophy and spinal muscular atrophy

Many neuromuscular diseases are genetically inherited or caused by mutations in motor function proteins. Two of the most prevalent neuromuscular diseases are Duchenne Muscular Dystrophy (DMD) and Spinal Muscular Atrophy (SMA), which are often diagnosed during the early years of life, contributing to life-long debilitation and shorter longevity. DMD is caused by mutations in the dystrophin gene resulting in critical muscle wasting, with cardiac or respiratory failure by age 30. Lack of dystrophin protein is the leading cause of degeneration of skeletal and cardiac muscle. Corticosteroids and artificial respirators remain as the gold-standard management of complications and have significantly extended the life span of these patients. Additionally, drug therapies including eteplirsen (EXONDYS 51®), golodirsen (VYONDYS 53™), and viltolarsen (VILTEPSO®) have been approved by the FDA to treat specific types of DMD. SMA is defined by the degeneration of the anterior horn cells in the spinal cord and destruction of motor neuron nuclei in the lower brain-stem caused by SMN1 gene deletion. Loss of SMN1 protein is partly compensated by SMN2 protein synthesis with disease severity being affected by the success of SMN2 gene synthesis. Evidence-based recommendations for SMA are directed towards supportive therapy and providing adequate nutrition and respiratory assistance as needed. Treatment and prevention of complications of muscle weakness are crucial for reducing the phenotype expression of SMA. Furthermore, drug therapies including injectables such as onasemnogene abeparvovec-xioi (ZOLGENSMA®), nusinersen (SPINRAZA®), and an oral-solution, risdiplam (EVRYSDI™), are medications that have been FDA-approved for the treatment of SMA. This review discusses the current and emerging therapeutic options for patients with DMD and SMA.

Safety and Treatment Effects of Nusinersen in Longstanding Adult 5q-SMA Type 3 - A Prospective Observational Study

Objective:

Spinal muscular atrophy (SMA) is a progressive autosomal recessive motor neuron disease caused by loss of the SMN1 gene. Based on randomized clinical trials in children with SMA type 1 and 2, Nusinersen has been approved as the first treatment for all types of SMA, including adults with SMA type 3.

Methods:

We evaluated the safety and treatment effects of Nusinersen in longstanding adult 5q-SMA type 3. Patients were treated with intrathecal loading doses at day 1, 14, 28 and 63, followed by maintenance dose every four months up to 300 days. We monitored the patients within SMArtCARE, a prospective open-label outcome study for disease progression, side effects and treatment efficacy, encompassing clinical examination including MRC sum score, vital capacity in sitting position (VC, VC % pred.), ALS Functional Rating Scale (ALS-FRS), 6-Minute-Walk-Test (6MWT), Revised Upper Limb Module (RULM), and Hammersmith Functional Rating Scale (HFMSE). We also measured biomarkers in the spinal fluid (phosphorylated neurofilament heavy chain pNFH, neuron-specific enolase NSE, proteins, ß-Amyloid 1–40, ß-Amyloid 1–42, tau and phospho-tau) and creatine kinase (CK). Assessments were performed at baseline, day 63 (V4), day 180 (V5) and day 300 (V6). For statistical analysis, we compared baseline to V4, V5 and V6, using the paired sample t-test. When there were significant differences, we added cohen's d and effect size r for evaluation of clinical meaningfulness.

Results:

19 patients were included, 17 of them have completed the observation period of 10 months (day 300, V6). Patients were aged 18 to 59 years with disease duration ranging from 6 to 53 years. Except for the 6MWT, the RULM and the peak cough flow, there were no relevant significant changes in all functional outcome assessments at V4, V5 or V6, compared to baseline. For the 6MWT, there was a statistically significant improvement at visit 5 and at visit 6. RULM-score increased significantly at V6, and peak cough flow at visit 5. In biomarker studies, there was a significant decline in NSE and pTAU as well as a slight increase in proteins. In safety analysis, overall, Nusinersen applications were well tolerated. Eleven patients reported adverse events that were related to the study procedures, comprising back pain in seven patients and post-lumbar-puncture headache following intrathecal administration in four patients. Post-lumbar-puncture headache was reported in three females and one male, in total eleven times of 108 punctures (10%). No serious adverse events occurred.

Conclusions:

This prospective observational study indicates a mild treatment effect in adults with long-standing SMA3 after 10 months of treatment with Nusinersen, which had never occurred in the natural history of the disease. In our cohort, the most significant outcome measures were the 6MWT with statistically significant changes after day 180 and day 300, RULM after day 300 and peak cough flow after day 180.

Health, wellbeing and lived experiences of adults with SMA: a scoping systematic review

BACKGROUND

Spinal muscular atrophy (SMA) is a neurodegenerative disease that has a substantial and multifaceted burden on affected adults. While advances in supportive care and therapies are rapidly reshaping the therapeutic environment, these efforts have largely centered on pediatric populations. Understanding the natural history, care pathways, and patient-reported outcomes associated with SMA in adulthood is critical to advancing health policy, practice and research across the disease spectrum. The aim of this study was to systematically review research investigating the healthcare, well-being and lived experiences of adults with SMA.

METHODS

In accordance with the Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines, seven electronic databases were systematically searched until January 2020 for studies examining clinical (physical health, natural history, treatment) and patient-reported (symptoms, physical function, mental health, quality of life, lived experiences) outcomes in adults with SMA. Study risk of bias and the level of evidence were assessed using validated tools.

RESULTS

Ninety-five articles met eligibility criteria with clinical and methodological diversity observed across studies. A heterogeneous clinical spectrum with variability in natural history was evident in adults, yet slow declines in motor function were reported when observational periods extended beyond 2 years. There remains no high quality evidence of an efficacious drug treatment for adults. Limitations in mobility and daily activities associated with deteriorating physical health were commonly reported, alongside emotional difficulties, fatigue and a perceived lack of societal support, however there was no evidence regarding effective interventions.

CONCLUSIONS

This systematic review identifies the many uncertainties regarding best clinical practice, treatment response, and long-term outcomes for adults with SMA. This comprehensive identification of the current gaps in knowledge is essential to guide future clinical research, best practice care, and advance health policy with the ultimate aim of reducing the burden associated with adult SMA.

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).

Emerging therapies and challenges in spinal muscular atrophy

Spinal muscular atrophy (SMA) is a hereditary neurodegenerative disease with severity ranging from progressive infantile paralysis and premature death (type I) to limited motor neuron loss and normal life expectancy (type IV). Without disease‐modifying therapies, the impact is profound for patients and their families. Improved understanding of the molecular basis of SMA, disease pathogenesis, natural history, and recognition of the impact of standardized care on outcomes has yielded progress toward the development of novel therapeutic strategies and are summarized. Therapeutic strategies in the pipeline are appraised, ranging from SMN1 gene replacement to modulation of SMN2 encoded transcripts, to neuroprotection, to an expanding repertoire of peripheral targets, including muscle. With the advent of preliminary trial data, it can be reasonably anticipated that the SMA treatment landscape will transform significantly. Advancement in presymptomatic diagnosis and screening programs will be critical, with pilot newborn screening studies underway to facilitate preclinical diagnosis. The development of disease‐modifying therapies will necessitate monitoring programs to determine the long‐term impact, careful evaluation of combined treatments, and further acceleration of improvements in supportive care. In advance of upcoming clinical trial results, we consider the challenges and controversies related to the implementation of novel therapies for all patients and set the scene as the field prepares to enter an era of novel therapies. Ann Neurol 2017;81:355–368