Reliability of hand-held dynamometry in spinal muscular atrophy

The Relevance of Spinal Muscular Atrophy Biomarkers in the Treatment Era

Spinal muscular atrophy (SMA) is a severe neuromuscular disorder that currently has an approved treatment for all forms of the disease. Previously, biomarkers were primarily used for diagnostic purposes, such as detecting the presence of the disease or determining a specific clinical type of SMA. Currently, with the availability of therapy, biomarkers have become more valuable due to their potential for prognostic, predictive, and pharmacodynamic applications. This review describes the most promising physiological, functional, imaging and molecular biomarkers for SMA, derived from different patients' tissues. The review summarizes information about classical biomarkers that are already used in clinical practice as well as fresh findings on promising biomarkers that have been recently disclosed. It highlights the usefulness, limitations, and strengths of each potential biomarker, indicating the purposes for which each is best suited and when combining them may be most beneficial.

Reliability, validity, and responsiveness of pinch strength assessment: a systematic review

PURPOSE

To summarize and critically appraise the quality of studies investigating psychometric properties of pinch strength assessment.

METHODS

Medical literature up to February 2024 was searched for studies reporting on at least one measurement property of pinch strength assessment. The quality of the evidence and the risk of bias were rated using COSMIN 2018 guidelines.

RESULTS

Thirty-three studies (1962 participants) were included. The majority (16/19) of reliability studies were of adequate to very good quality. Seven of 12 studies of validity were rated as adequate or very good. The quality of the eight responsiveness studies was adequate. Reliability was good to excellent (ICC > 0.75) for neurological conditions, and excellent (ICC > 0.90) for musculoskeletal disorders and healthy participants. Pinch strength showed strong to very strong correlations with grip strength (r = 0.72-0.92), moderate to strong correlations with assessments of dexterity (r = 0.78-0.80), and weak to moderate correlation with patient-reported outcome measures (r = 0.03-0.50). Varied results were found for pinch strength responsiveness in a small number of studies.

CONCLUSIONS

Pinch strength assessment is reliable. Validity and responsiveness are less reported, but there is a strong correlation between pinch and grip strength, and a moderate correlation with dexterity.

Cancer-associated muscle weakness - From triggers to molecular mechanisms

Skeletal muscle weakness is a debilitating consequence of many malignancies. Muscle weakness has a negative impact on both patient wellbeing and outcome in a range of cancer types and can be the result of loss of muscle mass (i.e. muscle atrophy, cachexia) and occur independently of muscle atrophy or cachexia. There are multiple cancer specific triggers that can initiate the progression of muscle weakness, including the malignancy itself and the tumour environment, as well as chemotherapy, radiotherapy and malnutrition. This can induce weakness via different routes: 1) impaired intrinsic capacity (i.e., contractile dysfunction and intramuscular impairments in excitation-contraction coupling or crossbridge cycling), 2) neuromuscular disconnection and/or 3) muscle atrophy. The mechanisms that underlie these pathways are a complex interplay of inflammation, autophagy, disrupted protein synthesis/degradation, and mitochondrial dysfunction. The current lack of therapies to treat cancer-associated muscle weakness highlight the critical need for novel interventions (both pharmacological and non-pharmacological) and mechanistic insight. Moreover, most research in the field has placed emphasis on directly improving muscle mass to improve muscle strength. However, accumulating evidence suggests that loss of muscle function precedes atrophy. This review primarily focuses on cancer-associated muscle weakness, independent of cachexia, and provides a solid background on the underlying mechanisms, methodology, current interventions, gaps in knowledge, and limitations of research in the field. Moreover, we have performed a mini-systematic review of recent research into the mechanisms behind muscle weakness in specific cancer types, along with the main pathways implicated.

'Reading the palm' - A pilot study of grip and finger flexion strength as an outcome measure in 5q spinal muscular atrophy

BACKGROUND

Innovative RNA modifying and gene replacement therapies are currently revolutionizing the therapeutic landscape in 5q-associated spinal muscular atrophy (SMA). In order to provide individual recommendations for choice of treatment and therapy (dis-) continuation, objective outcome measures are needed. The purpose of this study was to determine whether maximum isometric voluntary grip and finger flexion strength is a useful sensitive outcome measure in children and adult patients with SMA.

METHODS

In this non-interventional, longitudinal pilot study, we assessed grip and finger flexion strength on 39 patients with SMA II and III (n = 16 children, mean age = 10.0; n = 23 adults, mean age = 38.4) using the Weber hand and finger dynamometer HFD 200. Grip and finger flexion strength, clinical examinations and motor function scores (Revised Upper Limb Module, Hammersmith Functional Motor Scale Expanded) were assessed over a 12-month treatment period concurrent with the nusinersen treatment.

RESULTS

Grip and finger flexion strength was highly associated with motor function and disease severity, SMA type and SMN2 copy number. During nusinersen treatment, grip and finger flexion strength significantly increased in children and adults with SMA.

CONCLUSION

Grip and finger flexion strength measured with the HFD 200 is a promising sensitive outcome measure for SMA.

Differential impact on motor unit characteristics across severities of adult spinal muscular atrophy

OBJECTIVE

To test the hypotheses that decomposition electromyography (dEMG) motor unit action potential (MUAP) amplitude and firing rate are altered in SMA; dEMG parameters are associated with strength and function; dEMG parameters are correlated with traditional electrophysiological assessments.

METHODS

Ambulatory and non-ambulatory adults with SMA on nusinersen and healthy controls were enrolled. MUAPs were decomposed from multielectrode surface recordings during 30-s maximum contraction of the abductor digiti minimi (ADM). Isometric strength, upper limb function, patient-reported function, and standard electrophysiologic measures of the ADM (compound muscle action potential [CMAP], single motor unit potential [SMUP], motor unit number estimation [MUNE]) were collected.

RESULTS

dEMG MUAP amplitudes were higher in ambulatory versus control and non-ambulatory groups and were higher in controls versus non-ambulatory SMA. In contrast, dEMG firing rates were higher in ambulatory versus non-ambulatory and control groups but similar between non-ambulatory and control. dEMG parameters showed moderate to strong positive correlation with strength and function whereas CMAP and MUNE better correlated with function than strength. SMUP did not correlate with strength, function, or dEMG MUAP amplitude. dEMG parameters show overall good test-retest reliability.

INTERPRETATION

dEMG provided reliable, noninvasive measure of MUAP amplitude size and firing rate and revealed divergent patterns across disease severity in adults with SMA. Firing rate enhancement, as seen in milder SMA, may provide a therapeutic avenue for improving function in more severe SMA, where firing rates appear preserved. MUAP amplitude size and firing rate, quantified with dEMG, may be promising monitoring biomarker candidates for noninvasive assessment of SMA.

Biomarkers in 5q-associated spinal muscular atrophy-a narrative review

5q-associated spinal muscular atrophy (SMA) is a rare genetic disease caused by mutations in the SMN1 gene, resulting in a loss of functional SMN protein and consecutive degeneration of motor neurons in the ventral horn. The disease is clinically characterized by proximal paralysis and secondary skeletal muscle atrophy. New disease-modifying drugs driving SMN gene expression have been developed in the past decade and have revolutionized SMA treatment. The rise of treatment options led to a concomitant need of biomarkers for therapeutic guidance and an improved disease monitoring. Intensive efforts have been undertaken to develop suitable markers, and numerous candidate biomarkers for diagnostic, prognostic, and predictive values have been identified. The most promising markers include appliance-based measures such as electrophysiological and imaging-based indices as well as molecular markers including SMN-related proteins and markers of neurodegeneration and skeletal muscle integrity. However, none of the proposed biomarkers have been validated for the clinical routine yet. In this narrative review, we discuss the most promising candidate biomarkers for SMA and expand the discussion by addressing the largely unfolded potential of muscle integrity markers, especially in the context of upcoming muscle-targeting therapies. While the discussed candidate biomarkers hold potential as either diagnostic (e.g., SMN-related biomarkers), prognostic (e.g., markers of neurodegeneration, imaging-based markers), predictive (e.g., electrophysiological markers) or response markers (e.g., muscle integrity markers), no single measure seems to be suitable to cover all biomarker categories. Hence, a combination of different biomarkers and clinical assessments appears to be the most expedient solution at the time.

New Clinical and Immunofluoresence Data of Collagen VI-Related Myopathy: A Single Center Cohort of 69 Patients

Pathogenetic mechanism recognition and proof-of-concept clinical trials were performed in our patients affected by collagen VI-related myopathies. This study, which included 69 patients, aimed to identify innovative clinical data to better design future trials. Among the patients, 33 had Bethlem myopathy (BM), 24 had Ullrich congenital muscular dystrophy (UCMD), 7 had an intermediate phenotype (INTM), and five had myosclerosis myopathy (MM). We obtained data on muscle strength, the degree of contracture, immunofluorescence, and genetics. In our BM group, only one third had a knee extension strength greater than 50% of the predicted value, while only one in ten showed similar retention of elbow flexion. These findings should be considered when recruiting BM patients for future trials. All the MM patients had axial and limb contractures that limited both the flexion and extension ranges of motion, and a limitation in mouth opening. The immunofluorescence analysis of collagen VI in 55 biopsies from 37 patients confirmed the correlation between collagen VI defects and the severity of the clinical phenotype. However, biopsies from the same patient or from patients with the same mutation taken at different times showed a progressive increase in protein expression with age. The new finding of the time-dependent modulation of collagen VI expression should be considered in genetic correction trials.

PREhabilitation of CAndidates for REnal Transplantation (PreCareTx) study: protocol for a hybrid type I, mixed method, randomised controlled trial

INTRODUCTION

Kidney transplant candidates (KTCs) need to be in optimal physical and psychological condition prior to surgery. However, KTCs often experience compromised functional capacity which can be characterised as frailty. Prehabilitation, the enhancement of a person's functional capacity, may be an effective intervention to improve the health status of KTCs. The PREhabilitation of CAndidates for REnal Transplantation (PreCareTx) study aims to examine the effectiveness of a multimodal prehabilitation programme on the health status of KTCs, and to explore the potential of implementation of prehabilitation in daily clinical practice.

METHODS AND ANALYSIS

This study uses a single centre, effectiveness-implementation hybrid type I study design, comprised of a randomised controlled trial and a mixed-methods study. Adult patients who are currently on the transplant waiting list or are waitlisted during the study period, at a university medical centre in The Netherlands, will be randomly assigned to either prehabilitation (n=64) or care as usual (n=64) groups. The prehabilitation group will undergo a 12-week home-based, tailored prehabilitation programme consisting of physical and/or nutritional and/or psychosocial interventions depending on the participant's deficits. This programme will be followed by a 12-week maintenance programme in order to enhance the incorporation of the interventions into daily life. The primary endpoint of this study is a change in frailty status as a proxy for health status. Secondary endpoints include changes in physical fitness, nutritional status, psychological well-being, quality of life and clinical outcomes. Tertiary endpoints include the safety, feasibility and acceptability of the prehabilitation programme, and the barriers and facilitators for further implementation.

ETHICS AND DISSEMINATION

Medical ethical approval was granted by the Medical Ethics Committee Groningen, Netherlands (M22.421). Written informed consent will be obtained from all participants. The results will be disseminated at international conferences and in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT05489432.

Baseline Range of Motion, Strength, Motor Function, and Participation in Youth with Hutchinson-Gilford Progeria Syndrome

AIMS

Limited information is available on impairments, activity limitations and participation restrictions in youth with Hutchinson-Gilford progeria syndrome (HGPS), a rare genetic premature aging disease. The purposes were to: (1) describe range of motion (ROM), grip, pinch and quadriceps strength, functional balance, walking endurance, and gross motor limitations and participation restrictions; (2) evaluate the association between ROM impairments and age; and (3) evaluate the association between the Gross Motor Function Measure-88 (GMFM) scores and lower extremity (LE) ROM, quadriceps strength, and age.

METHODS

Upper and LE ROM, grip, pinch and quadriceps strength, Timed Up and Go (TUG), Six Minute Walk Test, GMFM-88, and Canadian Occupational Performance Measure data were recorded for 38 participants with HGPS.

RESULTS

All youth exhibited ROM impairments and most displayed decreased grip and pinch strength, walking endurance, and gross motor skills when compared to same-aged peers. However, the majority had good functional balance with TUG scores in the normal range. Participation restrictions included difficulty keeping up with peers when walking and difficulty completing activities of daily living. Some ROM measurements were negatively associated with age indicating that older participants had more extensive ROM limitation than younger participants.

CONCLUSIONS

Physical and occupational therapists can use this information when evaluating youth with HGPS, designing a plan of care, and providing treatment interventions.

Biochemical and clinical biomarkers in adult SMA 3-4 patients treated with nusinersen for 22 months

OBJECTIVE

To investigate biomarkers of disease progression in cerebrospinal fluid (CSF) and serum in adult patients with spinal muscular atrophy (SMA). Furthermore, we assess the clinical response to nusinersen treatment in adults with SMA over a longer follow-up period than the previously reported 6-14 months.

METHODS

We included 16 adults with SMA type 3-4 for nusinersen treatment over 22 months in this prospective study. We evaluated chitotriosidase-1 (CHIT1) and chitinase-3-like protein 1 (YKL-40) as neuroinflammatory biomarkers in CSF, and neurofilament light chain (NfL) and heavy chain (pNfH) as neurodegenerative markers in CSF and serum at baseline, month 6, 14 and 22, together with a wide range of clinical outcome measures.

RESULTS

Levels of CHIT1 increased significantly (p = 0.048) throughout the 22-month treatment period and pNfH decreased significantly (p = 0.022) in CSF, but both did not correlate with clinical outcome measures. YKL-40 correlated strongly with neurofilaments in CSF (rho = 0.76) and decreased significantly (p = 0.037) in patients with improvements in the revised upper limb module (RULM). Finally, patients showed significant improvements in hand grip strength, hand motor function, medical research council (MRC) sum score, and peak expiratory flow (PEF) after 22 months of treatment.

INTERPRETATION

YKL-40 in CSF correlated with clinical improvements during nusinersen treatment. In contrast, CHIT1 and pNfH in CSF changed significantly during treatment but did not correlate with clinical outcomes. Finally, we demonstrated a sustained clinical effect of nusinersen treatment in adults after 22 months.

Revised upper limb module in type II and III spinal muscular atrophy: 24-month changes

The aim of the study was to establish 24-month changes in a large cohort of type II and III spinal muscular atrophy (SMA) patients assessed with the Revised Upper Limb Module (RULM), a tool specifically developed to assess upper limb function in SMA. We included 107 patients (54 type II and 53 type III) with at least 24-months follow up. The overall RULM 24-month changes showed a mean decline of -0.79 points. The difference between baseline and 24 months was significant in type II but not in type III patients. There was also a difference among functional subgroups but not in relation to age. Most patients had 24-month mean changes within 2 points, with 23% decreasing more than 2 points and 7% improving by >2 points. Our results suggest an overall progressive decline in upper limb function over 24 months. The negative changes were most notable in type II, in non-ambulant type III and with a different pattern of progression, also in non-sitter type II. In contrast, ambulant type III showed relative stability within the 24-month follow up. These findings will help in the interpretation of the real world data collected following the availability of new therapeutic approaches.

Neurofilament Levels in CSF and Serum in an Adult SMA Cohort Treated with Nusinersen

OBJECTIVE

To retrospectively evaluate the utility of serum and cerebrospinal fluid (CSF) levels of neurofilament light chain (NfL) and phosphorylated neurofilament heavy chain (pNfH) as biomarkers for spinal muscular atrophy (SMA) progression and response to nusinersen treatment.

METHODS

NfL and pNfH levels were quantified using single molecular array (SIMOA) in CSF of 33 adult SMA patients (SMN copy number 3-5) before and in response to nusinersen treatment. In 11 of the patients, blood serum samples were also collected. CSF NfL and pNfH from patients were compared to CSF Nfs from age-matched controls without neurological disease (n = 6). For patients, pearson correlation coefficients (r) were calculated to investigate associations between Nf levels and other functional outcome measures.

RESULTS

Nf levels were similar between SMA and control adults and showed no change in response to nusinersen treatment in CSF or serum. Cross-sectional analyses showed an increase in CSF NfL and pNfH with age in patients (NfL p = 0.0013; pNfH p = 0.0035) and an increase in CSF NfL in controls (p = 0.002). In non-ambulatory patients, baseline serum pNfH showed a negative correlation with multiple strength and functional assessment metrics including Revised Upper Limb Module (r = -0.822, p = 0.04), upper extremity strength (r = -0.828, p = 0.042), lower extremity strength (r = -0.860, p = 0.028), and total strength (r = -0.870, p = 0.024).

CONCLUSIONS

Nf levels did not change in response to nusinersen in adults with SMA and were not different from controls. In patients and controls, we detected an age-related increase in baseline CSF NfL and pNfH levels. Though some associations were identified, our results suggest Nf levels are not preditive or prognostic biomarkers in this population.

Two Years of Improved Neurological Function With Nusinersen in a 48-Year-Old Patient With Spinal Muscular Atrophy Type 3

INTRODUCTION

Nusinersen antisense oligonucleotide infusions have been shown to be effective in the treatment spinal muscular atrophy. The majority of the evidence has been collected in young type 1 and type 2 patients, and evidence of efficacy in adult patients is limited.

CASE REPORT

A 48-year-old woman with spinal muscular atrophy type 3 who has received the loading dose and 8 maintenance infusions over an 8-month period. Grip and pinch strength, measured by hand-held dynamometry measured at baseline and in 6 to 12 months interval improved over a 24-month period. She also reported multiple other subjective improvements in function.

CONCLUSIONS

This is the first published case of nusinersen in a middle-aged adult with spinal muscular atrophy. Sustained clinically meaningful improvement may be possible with nusinersen initiation in mid adulthood.

Hand-held dynamometry for assessment of muscle strength in patients with inflammatory myopathies

OBJECTIVES

Muscle weakness in idiopathic inflammatory myopathies (IIMs) is conventionally assessed using manual muscle testing (MMT). However, more objective tools must be developed to accurately and reliably quantify muscle strength in myositis patients. Hand-held dynamometry (HHD) is a quantitative, portable device with reported reliability in neuromuscular disorders. Our aim was to assess the reliability, validity and responsiveness of HHD in myositis.

METHODS

Myositis patients [DM, necrotizing myopathy (NM), PM and anti-synthetase syndrome] evaluated at the University of Pittsburgh myositis centre were prospectively enrolled. Each patient was assessed at 0, 3 and 6 months for validated outcome measures of myositis disease activity and physical function. At each visit, muscle strength was assessed using both MMT and HHD (Micro FET2, Hoggan Health Industries, Draper, UT, USA). The reliability, validity and responsiveness of the HHD was assessed using standard statistical methods.

RESULTS

Fifty IIM patients (60% female; mean age 51.6 years; 6 PM, 9 NM, 24 DM and 11 anti-synthetase syndrome) were enrolled. HHD showed strong test-retest intrarater reliability (r = 0.96) and interrater reliability (r = 0.98). HHD correlated significantly with the MMT score (r = 0.48, P = 0.0006) and myositis disease activity and functional measures. Longitudinal analysis showed a significant and strong association between the HHD and MMT as well as 2016 ACR/EULAR myositis response criteria (r = 0.8, P < 0.0001) demonstrating responsiveness. The mean effect size and standardized response mean of HHD was large: 0.95 and 1.03, respectively. MMT had a high ceiling effect compared with HHD.

CONCLUSION

HHD demonstrated strong reliability, construct validity and responsiveness in myositis patients. External validation studies are required to confirm these findings.

Neck and Trunk Muscle Strength in Children With Spinal Muscular Atrophy Is Lower Than in Healthy Controls and Depends on Disease Type

Background: Neck and trunk muscle strength and relationship with motor function in individuals with spinal muscular atrophy (SMA) is not investigated well. Information on maximum muscle strength that children with SMA may develop considerably expands the possibilities of assessing the effectiveness of pharmacological treatment methods and therapeutic procedures. This study sought to assess neck and trunk muscle strength in patients with SMA and to compare it with values noted in healthy children.

Methods: The study involved 56 individuals with SMA aged 5–16 not treated pharmacologically, including 9 patients with SMA type 1 (SMA1), 27 with SMA type 2 (SMA2), and 20 with SMA type 3 (SMA3). The control group included 111 healthy individuals aged 5–16. Neck and trunk muscle strength was assessed by means of a maximum voluntary isometric contraction method with the use of a handheld digital muscle tester MICROFET2. Moreover, relative strength was also calculated by standardising the maximum voluntary isometric contraction according to body mass. The Kruskal–Wallis test, Mann–Whitney U-test, and Spearman's rank correlation were used for statistical analysis.

Results: The reliability of the neck and trunk muscle strength measurements with the handheld digital muscle tester was excellent with ICC > 0.9. The values of muscle strength in SMA groups were significantly lower than in the control group. The values of relative torque of the neck muscles expressed in percentage values calculated with regard to the control group were at the level of 47.6–51.6% in SMA1 group, 54.8–58.1% in SMA2 group and 80.6–90.3% in SMA3 group. The percentage values for upper and lower trunk muscle strength were at the level of 42.6–68.4% in SMA1 group, 56.9–75.4% in SMA2 group and 76.7–94.8% in SMA3 group.

Conclusion: Handheld dynamometry provides reliable measures of neck and trunk muscle strength in SMA children. Neck and trunk muscle strength in children with SMA is lower than in healthy controls and depends on disease type, which confirms the theory based on clinical observations. Further, study is needed to investigate the effect of pharmacological treatment on the strength of the neck/trunk muscles, and relationship between neck and trunk muscle strength and motor capabilities.

Quantification of disease progression in spinal muscular atrophy with muscle MRI-a pilot study

OBJECTIVES

Quantitative MRI (qMRI) of muscles is a promising tool to measure disease progression or to assess therapeutic effects in neuromuscular diseases. Longitudinal imaging studies are needed to show sensitivity of qMRI in detecting disease progression in spinal muscular atrophy (SMA). In this pilot study we therefore studied one-year changes in quantitative MR parameters in relation to clinical scores.

METHODS

We repeated quantitative 3 T MR analysis of thigh muscles and clinical testing one year after baseline in 10 treatment-naïve patients with SMA, 5 with Type 2 (21.6 ± 7.0 years) and 5 with Type 3 (33.4 ± 11.9 years). MR protocol consisted of Dixon, T₂ mapping and diffusion tensor imaging (DTI). The temporal relation of parameters was examined with a mixed model.

RESULTS

We detected a significant increase in fat fraction (baseline, 38.2% SE 0.6; follow-up, 39.5% SE 0.6; +1.3%, p = 0.001) in all muscles. Muscles with moderate to high fat infiltration at baseline show a larger increase over time (+1.6%, p < 0.001). We did not find any changes in DTI parameters except for low fat-infiltration muscles (m. adductor longus and m. biceps femoris (short head)). The T₂ of muscles decreased from 28.2 ms to 28.0 ms (p = 0.07). Muscle strength and motor function scores were not significantly different between follow-up and baseline.

CONCLUSION

Longitudinal imaging data show slow disease progression in skeletal muscle of the thigh of (young-) adult patients with SMA despite stable strength and motor function scores. Quantitative muscle imaging demonstrates potential as a biomarker for disease activity and monitoring of therapy response.

Effect of Discontinuation of Nusinersen Treatment in Long-Standing SMA3

BACKGROUND

Spinal muscular atrophy is an autosomal recessive neuromuscular disease leading to ongoing degeneration of anterior horn cells in the spinal cord. Nusinersen is the first approved treatment for the condition, an intrathecally administered antisense oligonucleotide. It modulates pre-RNA splicing of the SMN2 gene and increases full-length SMN protein expression, thereby increasing SMN protein levels. The benefit of Nusinersen for patients with spinal muscular atrophy type 3 (SMA3) has recently been shown in several real-world cohorts.

OBJECTIVE

We aim to elucidate not only the effect of therapy with Nusinersen, but the development of the disease course after discontinuation of treatment. To our knowledge, there are so far no reports on the effects of Nusinersen discontinuation.

METHODS

We report on a 45-year-old female patient with genetically confirmed SMA3 and a disease duration of 40 years prior to treatment onset.

RESULTS

The patient was non-ambulantory, best motor function at treatment onset was holding arms with support, reflected in MRC of 3/5 in upper limbs. After having received Nusinersen for 11 months without complications, the patient showed improvement in motor functions, as measured by hand grip measurement (HGS), Hammersmith Functional Rating Scale Expanded (HFMSE), and Revised Upper Limb Module (RULM). Due to worsening of a pre-existing anxiety disorder, treatment was discontinued after six injections. Sixteen months later, progression of the disease became evident with worsening of HFMSE and RULM scores, while hand strength remained stable.

CONCLUSION

Treatment with Nusinersen in SMA3 improves motor function in longstanding disease even in clinically advanced stages; however, after discontinuation of treatment, further progression mirroring the natural history of the disease is anticipated.

Quadriceps muscle strength in Duchenne muscular dystrophy and effect of corticosteroid treatment

Objectives

In Duchenne muscular dystrophy, quadriceps weakness is recognized as a key factor in gait deterioration. The objective of this work was three-fold: first, to document the strength of the quadriceps in corticosteroid-naïve DMD boys; second, to measure the effect of corticosteroids on quadriceps strength; and third, to evaluate the correlation between baseline quadriceps strength and the age when starting corticosteroids with the loss of ambulation.

Methods

Quadriceps muscle strength using hand-held dynamometry was measured in 12 ambulant DMD boys who had never taken corticosteroids and during corticosteroid treatment until the loss of ambulation.

Results

Baseline quadriceps muscle strength at 6 years of age was 28% that of normal children of the same age; it decreased to 15% at 8 years and to 6% at 10 years. The increase in quadriceps muscle strength obtained after 1 year of corticosteroid treatment had a strong direct correlation with the baseline strength (R = 0.96). With corticosteroid treatment, the age of ambulation loss showed a very strong direct relationship (R = 0.92) with baseline quadriceps muscle strength but only a very weak inverse relationship (R = -0.73) with the age of starting treatment. Age of loss of ambulation was 10.3 ± 0.5 vs 19.1 ± 4.7 (P < 0.05) in children with baseline quadriceps muscle strength less than or greater than 40 N, respectively.

Conclusions

Corticosteroid-naïve DMD boys have a quantifiable severe progressive quadriceps weakness. This long-term study, for the first time, shows that both of the positive effects obtained with CS treatment, i.e. increasing quadriceps strength and delaying the loss of ambulation, have a strong and direct correlation with baseline quadriceps muscle strength. As such, hand-held dynamometry may be a useful tool in the routine physical examination and during clinical trial assessment.

Spinal Muscular Atrophy: The Use of Functional Motor Scales in the Era of Disease-Modifying Treatment

Spinal muscular atrophy (SMA) is a genetic condition characterized by progressive motoneuron loss. Infants affected by SMA type 1 do not gain developmental milestones and acutely decline, requiring ventilatory support. Several scales are used to assess motor disability and its progression in SMA. Recently, 3 disease-modifying therapies have been approved for SMA patients: nusinersen, an intrathecal antisense oligonucleotide enhancing SMN protein production by the SMN2 gene, risdiplam, also influencing the SMN2 gene to stimulate SMN production but administered orally, and onasemnogene abeparvovec-xioi, an SMN1 gene replacement therapy. Thus, the functional scales should now be applicable for patients improving their motor function over time to assess treatment efficacy. In this paper, we compare different functional scales used in SMA patients. Their usefulness in different SMA types, age groups, and feasibility in daily clinical practice is described below. Some changes in motor function assessments in SMA are also suggested.

Effect of mirror therapy on hand functions in Egyptian chronic stroke patients

Background

Most stroke survivors (more than 60%) suffer from persistent neurological impairments that significantly affect activities of daily living. Hand functions are essential for doing daily living and working activities. Mirror therapy is shown to be effective in improving hand functional recovery in stroke patients.

Objective

This study aimed to determine the effect of mirror therapy on improving hand functions in Egyptian chronic stroke patients.

Subjects and methods

Thirty chronic ischemic stroke patients from both sexes participated in the study. Their ages ranged from 45 to 65 years. They were randomly assigned into two equal groups: the study group that received a selected physical therapy program in addition to the mirror therapy and the control group that received the same selected physical therapy program but without a mirror therapy. Treatment sessions were conducted three times per week for 8 weeks. Range of motion (ROM) of the wrist extension and forearm supination, hand grip strength, and the time of Jebson Hand Function Test (JHFT) were measured before and after the treatment program.

Results

There were statistically significant increases in the range of motion of the wrist extension and forearm supination and hand grip strength with a decrease in the time of Jebson Hand Function Test in both groups post-treatment. Post-treatment improvement was more significant in the study group compared to the control group.

Conclusion

Mirror therapy had a positive effect on improving hand motor functional skills in a sample of Egyptian chronic stroke patients.

Optimizing hand-function patient outcome measures for inclusion body myositis

Inclusion body myositis is the most commonly acquired myopathy after the age of 45. The slowly progressive and heterogeneous disorder is a challenge for measuring clinical trial efficacy. One current method for measuring progression utilizes the Inclusion Body Myositis-Functional Rating Scale. We have found that the upper extremity domain scores in the Inclusion Body Myositis-Functional Rating Scale do not consistently change until there is extreme loss of grip and finger flexor strength. Therefore, we performed a cross-sectional observational study of 83 inclusion body myositis patients and 38 controls recruited at the 2019 Annual Patient Conference of The Myositis Association. We evaluated new Inclusion Body Myositis Patient-Reported Outcome measures for upper extremity function modified from the NIH Patient-Reported Outcomes Measurement Information System as well as pinch and grip strength. We found that Patient-Reported Outcome measures hand-function have a higher correlation with pinch and grip strength than the Inclusion Body Myositis-Functional Rating Scale.

Nusinersen treatment significantly improves hand grip strength, hand motor function and MRC sum scores in adult patients with spinal muscular atrophy types 3 and 4

BACKGROUND

Nusinersen recently became available as the first treatment for Spinal Muscular Atrophy (SMA) and data on its effectiveness and safety in adult SMA patients are still scarce.

METHODS

We evaluated the effectiveness and safety of nusinersen treatment during 14 months in 16 adult patients with SMA types 3 and 4 in a prospective study, and retrospectively detailed the natural history of 48 adult SMA patients types 2, 3 and 4.

RESULTS

Hand grip strength (p = 0.03), hand motor function (p = 0.04) as assessed by a sub-score of the Revised Upper Limb Module (RULM) and the Medical Research Council (MRC) sum score (p = 0.04) improved significantly at month 14. Importantly, the MRC sum score had declined significantly (p < 0.01) prior to start of treatment in these patients. A minimal clinically important difference (MCID) in the Hammersmith Functional Motor Scale Expanded (HFMSE) and RULM scores was achieved in 31% and 50% of the patients, respectively, but the mean changes from baseline failed to reach significance. Forced Vital Capacity (FVC) transiently increased at month 6 (p = 0.01), whereas the Peak Expiratory Flow (PEF) did not. The Activity Limitations scale declined significantly prior to start of treatment (p < 0.01) and showed an improvement with nusinersen which was not significant. The safety evaluation did not reveal serious adverse events and no signs of nephrotoxicity or antisense oligonucleotide (ASO)-mediated inflammation.

CONCLUSIONS

We conclude that hand grip strength and hand motor function, as well as MRC sum scores improved significantly in nusinersen-treated adult patients with SMA types 3 and 4.

Box and block test, hand grip strength and nine-hole peg test: correlations between three upper limb objective measures in multiple sclerosis

BACKGROUND AND PURPOSE

Limited data are available in the literature for upper limb impairment in multiple sclerosis (MS). This study aimed to report the distribution of values of hand grip strength (HGS), of the box and block test (BBT) and of the nine-hole peg test (9HPT) correlated with demographic and clinical data in subjects with MS.

METHODS

This study involved five Italian neurological centres. The inclusion criteria were age ≥ 18, MS diagnosis, stable disease phase, right-hand dominance. All subjects underwent HGS, BBT and 9-HPT evaluation.

RESULTS

In all, 202 subjects with MS were enrolled: 137 females; mean age 48.4 years; mean Expanded Disability Status Scale (EDSS) 4.17; mean disease duration 14.12 years; disease course 129 relapsing-remitting, 21 primary progressive and 52 secondary progressive MS subjects; mean right HGS 25.3 kg, left 23.2 kg; mean right BBT 45.7 blocks, left 44.9 blocks; mean right 9-HPT 30.7 s, left 33.4 s. All results were statistically significantly different compared to healthy controls. HGS, BBT and 9-HPT were associated with age, EDSS and disease duration, whilst disease course correlated with BBT and 9-HPT. The BBT and 9-HPT scores significantly differed according to level of disability (EDSS ≤3.0, 3.5-5.5, ≥6.0).

CONCLUSION

Hand grip strength and BBT value distribution in a large MS population is reported. Correlations between HGS, BBT and 9-HPT were generally low.

The association of hand grip strength with functional measures in non-ambulatory children with Duchenne muscular dystrophy

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a disease characterized by progressive loss of muscle fiber, gradually from proximal to distal. Although a few studies have investigated hand grip strength in non-ambulatory DMD patients, a lack of literature was found determining its relationship with functional capacity.

OBJECTIVE

The aim of this study was to determine the associations between hand grip strength and functional measures in non-ambulatory children with DMD.

METHODS

Hand grip strength was evaluated using a dynamometer in children with DMD. The children with DMD were evaluated with the Turkish version of the Egen Klassifikation Scale Version 2 (EK2) for global functional capacity, the Performance of Upper Limb (PUL) for upper limb functional performance and the ABILHAND-Kids for hand ability.

RESULTS

The mean age of 38 DMD children was 12.02 ± 1.99 years. Dominant hand grip strength of the children with DMD was higher than the non-dominant hand (p < 0.05). The EK2 was 13.02 ± 5.50, PUL was 49.86 ± 14.34 and ABILHAND-Kids was 26.81 ± 7.59. Hand grip strength was found to be correlated with the EK2 (p < 0.05).

CONCLUSIONS

It is known that measuring functional ability and strength in very weak children with DMD has been difficult and complex for therapists/clinicians in the clinical environment. Although there is a moderate correlation, hand grip strength may be used in clinical practice as a practical assessment tool to have an immediate insight into the global functional capacity in non-ambulatory DMD children.

Portable fixed dynamometry to quantify ankle dorsiflexion force

INTRODUCTION

Quantifying muscle strength is critical in clinical and research settings. A rapid and objective method is ideal. The primary objective of this study was to examine the reliability of a novel device, the rapid objective quantification- tibialis anterior (ROQ-TA), which quantifies the dorsiflexion force of the tibialis anterior, and to assess its validity against isokinetic dynamometry (IKD).

METHODS

Ankle dorsiflexion of 20 healthy subjects was assessed by 3 modalities, ROQ-TA, manual muscle testing, and isokinetic dynamometry, over 2 testing sessions.

RESULTS

The intraclass correlation coefficient [ICC_(2,1) ] for reliability was 0.872 (0.677-0.949) for the ROQ-TA and 0.892 (0.728-0.957) for IKD. For validity, the ICC_(2,1) values for the ROQ-TA and IKD were in good agreement, with 0.672 (0.17-0.87) in the first testing session and 0.769 (0.42-0.91) in the second session.

DISCUSSION

The ROQ-TA is a valid and reliable device to test ankle dorsiflexion force in a healthy population. Muscle Nerve, 2018.

Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy

Background

The majority of individuals with spinal muscular atrophy (SMA) experience progressive skeletal deformities which may affect the quality of life and mobility. To date, no studies have evaluated the reliability of tests assessing body posture and joint mobility in SMA patients. The purpose of this study was to assess the reliability of Cervical Rotation test (CR), Supine Angle of Trunk Rotation test (SATR), Hip Extension test (HE) and Pelvic Obliquity test (PO) developed to evaluate the musculoskeletal system in SMA individuals.

Methods

Thirty individuals (12 girls and 18 boys) aged 4–15 with SMA type II (n = 24) and III (n = 6) confirmed by genetic examinations were qualified for the study. The participants were examined twice by three physiotherapists on the same day. The examination included four tests, i.e. CR, SATR, HE and PO tests aimed at assessing ranges of rotation in the cervical spine, chest deformities, ranges of hip extension and pelvis position while sitting. Statistical calculations were made with the use of statistical software IBM SPSS Statistics version 20. Reliability was assessed using the Intraclass Correlation Coefficient (ICC).

Results

Intraobserver reliability was excellent for CR (ICC range 0.839–0.911), SATR (ICC range 0.918–0.939 - the upper part of the sternum; ICC range 0.951–0.975 - the lower part of the sternum), HE (ICC range 0.988–0,991) and PO (ICC range 0.896–0.935) tests.

The interobserver ICC reached the excellent values in CR (ICC range 0.912–0.920), SATR (ICC = 0.888 - the upper part of the sternum, ICC = 0.951 - the lower part of the sternum), HE (ICC range 0.922–0.923) and PO (ICC = 0.928) tests.

Conclusions

CR, SATR, HE and PO tests are reliable and may be used for examining individuals with SMA. The application of these tests provides a possibility to detect early changes in the musculoskeletal system in children and adolescents and to assess the effectiveness of the implemented pharmacotherapy and rehabilitation.

Isometric muscle strength in children and adolescents using Handheld dynamometry: reliability and normative data for the Brazilian population

OBJECTIVE

Isometric muscle strength measured by Handheld dynamometer indicates physical ability. There is no normative data for the Brazilian population. This study aims (a) to describe the development of isometric muscle strength in healthy children and adolescents 5-15 years of age; (b) to evaluate Handheld dynamometer inter and intra-rater reliability.

METHODS

Isometric muscle strength was obtained for shoulder abduction, elbow and knee flexion and extension, dorsiflexion and plantar flexion in 55 boys and 55 girls, aged between 5 and 15 years. Inter-rater reliability was determined based on the evaluation of 2 raters, with a 20-min interval between them. Intra-rater reliability was based on 2 evaluations from the same rater, one week apart. Interclass correlation coefficient (ICC_{2,1; 3,1}), Bland Altman plots and linear regression models with mixed effects were used to quantify inter and intra-rater reliability, agreement and associations with physical activity level and maturational factors.

RESULTS

A linear development of isometric muscular strength was observed for ages between 5 and 10. After age 10, boys showed a larger isometric muscular strength, when compared to girls. Both inter and intra-rater measurements of the Handheld dynamometer are reliable (ICC>0.63).

CONCLUSIONS

This study shows increase in isometric muscle strength starting at 10 years of age for boys, when compared to girls and inter and intra-rater reliability for the assessment of isometric strength, using the Handheld dynamometer for the muscle groups tested on the dominant and non-dominant side, for children between 5 and 15 years of age.

New quantitative method for evaluation of motor functions applicable to spinal muscular atrophy

OBJECTIVE

The aim of this study was to develop and introduce new method to quantify motor functions of the upper extremity.

METHODS

The movement was recorded using a three-dimensional motion capture system, and the movement trajectory was analyzed using newly developed two indices, which measure precise repeatability and directional smoothness. Our target task was shoulder flexion repeated ten times. We applied our method to a healthy adult without and with a weight, simulating muscle impairment. We also applied our method to assess the efficacy of a drug therapy for amelioration of motor functions in a non-ambulatory patient with spinal muscular atrophy. Movement trajectories before and after thyrotropin-releasing hormone therapy were analyzed.

RESULTS

In the healthy adult, we found the values of both indices increased significantly when holding a weight so that the weight-induced deterioration in motor function was successfully detected. From the efficacy assessment of drug therapy in the patient, the directional smoothness index successfully detected improvements in motor function, which were also clinically observed by the patient's doctors.

CONCLUSION

We have developed a new quantitative evaluation method of motor functions of the upper extremity. Clinical usability of this method is also greatly enhanced by reducing the required number of body-attached markers to only one. This simple but universal approach to quantify motor functions will provide additional insights into the clinical phenotypes of various neuromuscular diseases and developmental disorders.

A PRELIMINARY STUDY OF AGE-SPECIFIC DIFFERENCES IN BALANCE, MUSCLE STRENGTH, AND POSTURAL SWAY FOR THE RISK OF FALLING

Fall is the main cause of activity decline for the elderly. In general, it has been known to be closely related to decline in muscle strength and physical balance. The age profile of the elderly has a very wide range from 60 to 90 or more. Therefore, this study was to determine age-specific risk factors for falling in elderly individuals. Elderly females were included either in the old group ([Formula: see text]75 years; [Formula: see text], with 11 fallers and 24 nonfallers) or the older group ([Formula: see text]75 years; [Formula: see text], with 14 fallers and 22 nonfallers). The following were assessed and compared between the age-based groups and between fall-based subgroups (fallers and nonfallers within a given age group): height, weight, mental state, balance on the Berg balance scale (BBS), muscle strength of nine muscle groups, and 20 variables of postural sway. The two age-based groups differed significantly in terms of height, weight, balance, and postural sway (total sway area, 95% ellipse area, root mean square, mean distance, and total power); on the other hand, the fall-based subgroups differed only in terms of the median frequency of postural sway. Furthermore, the strength of the hip abductors displayed an interaction effect between age and fall status, and the result of main effect analysis revealed significant differences between fallers from the two age-based groups. These results confirm that extraction of specific factors for each age group is necessary to perform fall detection and prevention studies for the healthy elderly.

[Upper limb functional assessment scale for children with Duchenne muscular dystrophy and Spinal muscular atrophy]

Duchenne muscular dystrophy (DMD) and Spinal muscular atrophy (SMA) causes significant disability and progressive functional impairment. Readily available instruments that assess functionality, especially in advanced stages of the disease, are required to monitor the progress of the disease and the impact of therapeutic interventions.

OBJECTIVE

To describe the development of a scale to evaluate upper limb function (UL) in patients with DMD and SMA, and describe its validation process, which includes self-training for evaluators.

PATIENTS AND METHOD

The development of the scale included a review of published scales, an exploratory application of a pilot scale in healthy children and those with DMD, self-training of evaluators in applying the scale using a handbook and video tutorial, and assessment of a group of children with DMD and SMA using the final scale. Reliability was assessed using Cronbach and Kendall concordance and with intra and inter-rater test-retest, and validity with concordance and factorial analysis.

RESULTS

A high level of reliability was observed, with high internal consistency (Cronbach a = 0.97), and inter-rater (Kendall W = 0.96) and intra-rater concordance (r = 0.97 to 0.99). The validity was demonstrated by the absence of significant differences between results by different evaluators with an expert evaluator (F = 0.023, p > .5), and by the factor analysis that showed that four factors account for 85.44% of total variance.

CONCLUSIONS

This scale is a reliable and valid tool for assessing UL functionality in children with DMD and SMA. It is also easily implementable due to the possibility of self-training and the use of simple and inexpensive materials.

Characterization of Strength and Function in Ambulatory Adults With GNE Myopathy

Objective:

To characterize the pattern and extent of muscle weakness and impact on physical functioning in adults with GNEM.

Methods:

Strength and function were assessed in GNEM subjects (n = 47) using hand-held dynamometry, manual muscle testing, upper and lower extremity functional capacity tests, and the GNEM-Functional Activity Scale (GNEM-FAS).

Results:

Profound upper and lower muscle weakness was measured using hand-held dynamometry in a characteristic pattern, previously described. Functional tests and clinician-reported outcomes demonstrated the consequence of muscle weakness on physical functioning.

Conclusions:

The characteristic pattern of upper and lower muscle weakness associated with GNEM and the resulting functional limitations can be reliably measured using these clinical outcome assessments of muscle strength and function.

Repeatability, consistency, and accuracy of hand-held dynamometry with and without fixation for measuring ankle plantarflexion strength in healthy adolescents and adults

INTRODUCTION

Hand-held dynamometry (HHD) is commonly used to measure ankle plantarflexion strength but has variable reliability measuring higher forces. Fixed HHD is suggested to improve reliability. We, therefore, compared the reliability, consistency, and accuracy of measuring plantarflexion strength.

METHODS

Plantarflexion strength was measured in 25 healthy individuals with fixed HHD and HHD alone. Intraclass correlation coefficients (ICC_2,2 ), SEM, minimal detectable change, and Spearman correlation coefficients were calculated to assess inter-trial repeatability, consistency, agreement, and accuracy.

RESULTS

Both methods were repeatable (ICC_2,2 0.96 to 0.98) and highly correlated (Spearman rho = 0.815; P < 0.01). Fixed HHD produced significantly higher force outputs. HHD alone provided more consistent force values.

CONCLUSIONS

Both methods of measuring ankle plantarflexion force were reliable. Force measured with fixed HHD will likely be more accurate for adults and individuals with greater strength, while HHD alone will be more consistent for individuals with lower strength. Muscle Nerve 56: 896-900, 2017.

Strength Testing in Motor Neuron Diseases

Loss of muscle strength is a cardinal feature of all motor neuron diseases. Functional loss over time, including respiratory dysfunction, inability to ambulate, loss of ability to perform activities of daily living, and others are due, in large part, to decline in strength. Thus, the accurate measurement of limb muscle strength is essential in therapeutic trials to best understand the impact of therapy on vital function. While qualitative strength measurements show declines over time, the lack of reproducibility and linearity of measurement make qualitative techniques inadequate. A variety of quantitative measures have been developed; all have both positive attributes and limitations. However, with careful training and reliability testing, quantitative measures have proven to be reliable and sensitive indicators of both disease progression and the impact of experimental therapy. Quantitative strength measurements have demonstrated potentially important therapeutic effects in both amyotrophic lateral sclerosis and spinobulbar muscular atrophy, and have been shown feasible in children with spinal muscular atrophy. The spectrum of both qualitative and quantitative strength measurements are reviewed and their utility examined in this review.

Effect of Gender, Disease Duration and Treatment on Muscle Strength in Myasthenia Gravis

INTRODUCTION

The aim of this observational, cross-sectional study was to quantify the potential presence of muscle weakness among patients with generalized myasthenia gravis (gMG). The influence of gender, treatment intensity and disease duration on muscle strength and disease progression was also assessed.

METHODS

Muscle strength was tested in 8 muscle groups by manual muscle testing and by hand-held dynamometry in 107 patients with gMG and 89 healthy age- and gender-matched controls. Disease duration, severity and treatment history were reviewed and compared with muscle strength.

RESULTS

Patients had reduced strength in all tested muscle group compared to control subjects (p<0.05). Women with gMG were stronger than men (decrease in strength 22.6% vs. 32.7% in men, P<0.05). Regional differences in muscle weakness were also evident, with proximal muscles being more affected. Interestingly, muscle strength did not correlate with disease duration and treatment intensity.

CONCLUSIONS

The results of this study show that in patients with gMG; 1) there is significant muscle weakness, 2) muscle weakness is more pronounced in men than women, 3) shoulder abductors, hip flexors, and neck muscles are the most affected muscle groups and 4) disease duration or treatment intensity alone are not predictors of loss of muscle strength in gMG.

Fall- and BBS-related differences in muscle strength and postural balance of the elderly

[Purpose] The purpose of this study was to compare the differences in muscle strength and postural balance between fallers and non-fallers. We also compared the difference between normal and impaired balance groups using the same subjects and the same variables. [Subjects and Methods] Seventy-one healthy elderly females (age: 75.1 ± 75 years; weight: 57.3 ± 57 kg; height: 150.1 ± 15 cm) who had high levels of physical activity participated [25 fallers (FG) vs. 46 non-fallers (NG); and 52 healthy balance group (HBG) and 19 impaired balance group (IBG) subjects]. To compare the groups, the muscle strengths of 9 muscle groups, and 20 variables of the instrumented standing balance assessment (2 area variables, 9 time-domain variables, and 9 frequency-domain variables) were assessed. [Results] The FG and NG could only be categorized based on the frequency-domain variables of the instrumented standing balance assessment. On the other hand, there were significant differences between HBG and IBG in height, 6 muscle strength, and 2 time-domain variables of the instrumented standing balance assessment. [Conclusion] These results suggest that muscle strength and standing balance are reflected in physical balance ability (i.e., BBS); however they are in sufficient for determining the actual occurrence of falls.

Autophagy activation in COL6 myopathic patients by a low-protein-diet pilot trial

A pilot clinical trial based on nutritional modulation was designed to assess the efficacy of a one-year low-protein diet in activating autophagy in skeletal muscle of patients affected by COL6/collagen VI-related myopathies. Ullrich congenital muscular dystrophy and Bethlem myopathy are rare inherited muscle disorders caused by mutations of COL6 genes and for which no cure is yet available. Studies in col6 null mice revealed that myofiber degeneration involves autophagy defects and that forced activation of autophagy results in the amelioration of muscle pathology. Seven adult patients affected by COL6 myopathies underwent a controlled low-protein diet for 12 mo and we evaluated the presence of autophagosomes and the mRNA and protein levels for BECN1/Beclin 1 and MAP1LC3B/LC3B in muscle biopsies and blood leukocytes. Safety measures were assessed, including muscle strength, motor and respiratory function, and metabolic parameters. After one y of low-protein diet, autophagic markers were increased in skeletal muscle and blood leukocytes of patients. The treatment was safe as shown by preservation of lean:fat percentage of body composition, muscle strength and function. Moreover, the decreased incidence of myofiber apoptosis indicated benefits in muscle homeostasis, and the metabolic changes pointed at improved mitochondrial function. These data provide evidence that a low-protein diet is able to activate autophagy and is safe and tolerable in patients with COL6 myopathies, pointing at autophagy activation as a potential target for therapeutic applications. In addition, our findings indicate that blood leukocytes are a promising noninvasive tool for monitoring autophagy activation in patients.

Robot-aided assessment of lower extremity functions: a review

The assessment of sensorimotor functions is extremely important to understand the health status of a patient and its change over time. Assessments are necessary to plan and adjust the therapy in order to maximize the chances of individual recovery. Nowadays, however, assessments are seldom used in clinical practice due to administrative constraints or to inadequate validity, reliability and responsiveness. In clinical trials, more sensitive and reliable measurement scales could unmask changes in physiological variables that would not be visible with existing clinical scores.In the last decades robotic devices have become available for neurorehabilitation training in clinical centers. Besides training, robotic devices can overcome some of the limitations in traditional clinical assessments by providing more objective, sensitive, reliable and time-efficient measurements. However, it is necessary to understand the clinical needs to be able to develop novel robot-aided assessment methods that can be integrated in clinical practice.This paper aims at providing researchers and developers in the field of robotic neurorehabilitation with a comprehensive review of assessment methods for the lower extremities. Among the ICF domains, we included those related to lower extremities sensorimotor functions and walking; for each chapter we present and discuss existing assessments used in routine clinical practice and contrast those to state-of-the-art instrumented and robot-aided technologies. Based on the shortcomings of current assessments, on the identified clinical needs and on the opportunities offered by robotic devices, we propose future directions for research in rehabilitation robotics. The review and recommendations provided in this paper aim to guide the design of the next generation of robot-aided functional assessments, their validation and their translation to clinical practice.

Six-minute walk test is reliable and valid in spinal muscular atrophy

INTRODUCTION

The Six-Minute Walk Test (6MWT) was adopted as a clinical outcome measure for ambulatory spinal muscular atrophy (SMA). However, a systematic review of measurement properties reported significant variation among chronic pediatric conditions. Our purpose was to assess the reliability/validity of the 6MWT in SMA.

METHODS

Thirty participants performed assessments, including the 6MWT, strength, and function. Reproducibility was evaluated by intraclass correlation coefficients. Criterion/convergent validity were determined using Pearson correlation coefficients.

RESULTS

Test-retest reliability was excellent. The 6MWT was associated positively with peak oxygen uptake, Hammersmith Functional Motor Scale Expanded (HFMSE), lower extremity manual muscle testing, knee flexion hand-held dynamometry, and inversely with 10-m walk/run. The 6MWT discriminates between disease severity, unlike the HFMSE.

CONCLUSIONS

This study documents measurement properties of reproducibility, positive criterion validity, and convergent validity with established clinical assessments and reaffirms the value of the 6MWT as a pivotal outcome measure in SMA clinical trials. Muscle Nerve 54: 836-842, 2016.

Resistance strength training exercise in children with spinal muscular atrophy

INTRODUCTION

Preliminary evidence in adults with spinal muscular atrophy (SMA) and in SMA animal models suggests exercise has potential benefits in improving or stabilizing muscle strength and motor function.

METHODS

We evaluated feasibility, safety, and effects on strength and motor function of a home-based, supervised progressive resistance strength training exercise program in children with SMA types II and III. Up to 14 bilateral proximal muscles were exercised 3 times weekly for 12 weeks.

RESULTS

Nine children with SMA, aged 10.4 ± 3.8 years, completed the resistance training exercise program. Ninety percent of visits occurred per protocol. Training sessions were pain-free (99.8%), and no study-related adverse events occurred. Trends in improved strength and motor function were observed.

CONCLUSIONS

A 12-week supervised, home-based, 3-day/week progressive resistance training exercise program is feasible, safe, and well tolerated in children with SMA. These findings can inform future studies of exercise in SMA.

The effects of electrical stimulation and exercise therapy in patients with limb girdle muscular dystrophy. A controlled clinical trial

Objective:

To evaluate and compare the effects of exercise therapy and electrical stimulation on muscle strength and functional activities in patients with limb-girdle muscular dystrophy (LGMD).

Methods:

This controlled clinical trial included 24 subjects who were diagnosed with LGMD by the Neurology Department of the Hacettepe University Hospital, Ankara, Turkey and were referred to the Physical Therapy Department between May 2013 and December 2014. Subjects were enrolled into an electrical stimulation (11 patients) group, or an exercise therapy (13 patients) group.

Results:

The mean age of patients was 31.62 years in the electrical stimulation group, and 30.14 years in the exercise therapy group. The most important results in this controlled clinical study were that the muscle strength in both groups was significantly decreased and post-treatment evaluation results indicated that muscle strength of the Deltoideus was higher in the electrical stimulation group, and the difference between the groups was maintained in the follow-up period (p<0.05). However, the muscle strength of quadriceps was similar in both groups, according to the post-treatment and follow-up evaluation results (p>0.05). Additionally, the electrical stimulation group presented more obvious overall improvements than the exercise therapy group according to muscle strength, endurance, and timed performance tests.

Conclusions:

Since no definitive treatments currently exist for patients with LGMD, these results provide important information on the role of exercise therapy and electrical stimulation for clinicians working in rehabilitation.

Reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease

OBJECTIVE

To evaluate the inter-rater and intra-rater reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease (ILD).

DESIGN

Test retest reliability of hand-held dynamometry for elbow flexor and knee extensor strength between two independent raters and two testing sessions.

SETTING

Physiotherapy department within a tertiary hospital.

PARTICIPANTS

Thirty participants with ILD of varying aetiology were included. Twenty participants completed the inter-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean (SD) age 73 (10) years, 11 male) and 21 participants completed the intra-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean age 71 (10) years, 11 male).

MAIN OUTCOME MEASURES

Mean muscle strength (kg). Agreement between the two raters and testing sessions was analyzed using Bland-Altman plots and reliability was estimated using intraclass correlation coefficients (ICC).

RESULTS

For elbow flexor strength there was a mean difference between raters of -0.6kg (limits of agreement (LOA) -5.6 to 4.4kg) and within raters of -0.3kg (LOA -2.8 to 2.3kg). The ICCs were 0.95 and 0.98, respectively. For knee extensor strength there was a mean difference between raters of -1.5kg (LOA -6.9 to 3.9kg) and within raters of -0.7kg (LOA -3.9 to 2.4kg). The ICCs were 0.95 and 0.97, respectively.

CONCLUSIONS

Hand-held dynamometry is reliable in measuring elbow flexor and knee extensor strength in people with ILD.

Within-session reliability and smallest real difference of muscle strength following nerve transfers in patients with brachial plexus injuries

PURPOSE

To quantify the smallest real difference (SRD) of muscle strength in patients with brachial plexus injuries (BPI) after nerve transfer.

METHODS

This study enrolled 16 patients with BPI who had C5-C6 and C5-C7 root injuries and who received nerve transfer of the spinal accessory nerve to the suprascapular nerve and fascicles of the ulnar nerve to the branch of the musculocutaneous nerve that innervates the biceps muscle. The quantitative peak strength of the shoulder abductor, external rotator, and elbow flexor in both arms were measured by the hand-held dynamometer. The SRD of each muscle was determined from the values of the intraclass correlation coefficient and standard error of measurement.

RESULTS

In the involved arm, peak strength ranged from 18% of the noninvolved (shoulder external rotator) to 40% of the noninvolved (shoulder abductor). The intraclass coefficient for within-session reliability revealed good to excellent reliability for muscles, ranging from 0.86 to 0.99 and 0.87 to 0.91 in the involved and noninvolved arms, respectively. The SRD values were low for the shoulder external rotator (2.6 kg) and high for the elbow flexor (3.3 kg).

CONCLUSIONS

The hand-held dynamometer is a device with good to excellent reliability for measuring the objective strength of patients with BPI in a single session. The SRD values established in the current study are more applicable for patients achieving a Medical Research Council grading of 3 or higher and can be used to detect real changes occurring after intervention, which can thereby differentiate real changes from changes that could be attributed to random variation in the measurements.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnosis II.

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.

Effects of underwater treadmill training on leg strength, balance, and walking performance in adults with incomplete spinal cord injury

OBJECTIVE

To document the effects of underwater treadmill training (UTT) on leg strength, balance, and walking performance in adults with incomplete spinal cord injury (iSCI).

DESIGN

Pre-test and post-test design.

SETTING

Exercise physiology laboratory.

PARTICIPANTS

Adult volunteers with iSCI (n = 11).

INTERVENTION

Participants completed 8 weeks (3 × /week) of UTT. Each training session consisted of three walks performed at a personalized speed, with adequate rest between walks. Body weight support remained constant for each participant and ranged from 29 to 47% of land body weight. Increases in walking speed and duration were staggered and imposed in a gradual and systematic fashion.

OUTCOME MEASURES

Lower-extremity strength (LS), balance (BL), preferred and rapid walking speeds (PWS and RWS), 6-minute walk distance (6MWD), and daily step activity (DSA).

RESULTS

Significant (P < 0.05) increases were observed in LS (13.1 ± 3.1 to 20.6 ± 5.1 N·kg(-1)), BL (23 ± 11 to 32 ± 13), PWS (0.41 ± 0.27 to 0.55 ± 0.28 m·s(-1)), RWS (0.44 ± 0.31 to 0.71 ± 0.40 m·s(-1)), 6MWD (97 ± 80 to 177 ± 122 m), and DSA (593 ± 782 to 1310 ± 1258 steps) following UTT.

CONCLUSION

Physical function and walking ability were improved in adults with iSCI following a structured program of UTT featuring individualized levels of body weight support and carefully staged increases in speed and duration. From a clinical perspective, these findings highlight the potential of UTT in persons with physical disabilities and diseases that would benefit from weight-supported exercise.

Nutritional status evaluation in patients affected by bethlem myopathy and ullrich congenital muscular dystrophy

Collagen VI mutations lead to disabling myopathies like Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). We have investigated the nutritional and metabolic status of one UCMD and seven BM patients (five female, three male, mean age 31 ± 9 years) in order to find a potential metabolic target for nutritional intervention. For this study, we used standard anthropometric tools, such as BMI evaluation and body circumference measurements. All results were compared to dual-energy X-ray absorptiometry (DXA), considered the “gold standard” method. Energy intake of each patient was evaluated through longitudinal methods (7-day food diary) while resting energy expenditure (REE) was predicted using specific equations and measured by indirect calorimetry. Clinical evaluation included general and nutritional blood and urine laboratory analyses and quantitative muscle strength measurement by hand-held dynamometry. BM and UCMD patients showed an altered body composition, characterized by low free fat mass (FFM) and high fat mass (FM), allowing us to classify them as sarcopenic, and all but one as sarcopenic-obese. Another main result was the negative correlation between REE/FFM ratio (basal energy expenditure per kilograms of fat-free mass) and the severity of the disease, as defined by the muscle megascore (correlation coefficient −0.955, P-value <0.001). We postulate that the increase of the REE/FFM ratio in relation to the severity of the disease may be due to an altered and pathophysiological loss of energetic efficiency at the expense of skeletal muscle. We show that a specific metabolic disequilibrium is related to the severity of the disease, which may represent a target for a nutritional intervention in these patients.

Muscle force, balance and falls in muscular impaired individuals with myotonic dystrophy type 1: a five-year prospective cohort study

Individuals with myotonic dystrophy type 1 (DM1) have progressive muscle weakness with gait and balance impairments. We explored prospectively the natural history of muscle force, gait, balance, balance confidence and walking ability in muscular affected individuals with DM1. After five years data from 43 individuals (m/f:18/25) were analysed. All measures of balance showed statistically significant deterioration (p < 0.001) with averaged yearly loss of function by 3-4%. In the group as a whole, loss of muscle force was statistically significant in all lower limb muscles measured after five years: changes relative to baseline force were median -6% to -18%. For males muscle force loss was statistically significant in all leg muscles, but only in hip flexors for women. After five years 100% of the men had fallen during the previous year and 67% three times or more, in contrast only 60% of the women had fallen in the previous year and 36% three times or more. The proportion of individuals seeking medical care the previous year, after falling, was more than doubled after five years, albeit the number of falls had not changed. Awareness of this increased risk of falls is important for caregivers and patients.

Sarcopenia and sarcopenic obesity in patients with muscular dystrophy

Aging sarcopenia and muscular dystrophy (MD) are two conditions characterized by lower skeletal muscle quantity, lower muscle strength, and lower physical performance. Aging is associated with a peculiar alteration in body composition called “sarcopenic obesity” characterized by a decrease in lean body mass and increase in fat mass. To evaluate the presence of sarcopenia and obesity in a cohort of adult patients with MD, we have used the measurement techniques considered golden standard for sarcopenia that is for muscle mass dual-energy X-ray absorptiometry (DXA), for muscle strength hand-held dynamometry (HHD), and for physical performance gait speed. The study involved 14 adult patients with different types of MD. We were able to demonstrate that all patients were sarcopenic obese. We showed, in fact, that all were sarcopenic based on appendicular lean, fat and bone free, mass index (ALMI). In addition, all resulted obese according to the percentage of body fat determined by DXA in contrast to their body mass index ranging from underweight to obese. Skeletal muscle mass determined by DXA was markedly reduced in all patients and correlated with residual muscle strength determined by HHD, and physical performances determined by gait speed and respiratory function. Finally, we showed that ALMI was the best linear explicator of muscle strength and physical function. Altogether, our study suggests the relevance of a proper evaluation of body composition in MD and we propose to use, both in research and practice, the measurement techniques that has already been demonstrated effective in aging sarcopenia.

Skeletal, neuromuscular and fitness impairments among children with newly diagnosed acute lymphoblastic leukemia

This study describes skeletal, neuromuscular and fitness impairments among 109 children (median age 10 [range 4-18] years, 65.1% male, 63.3% white) with acute lymphoblastic leukemia (ALL). Outcomes were measured 7-10 days after diagnosis and compared to age- and sex-specific expected values. Associations between function and health-related quality of life (HRQL) were evaluated with logistic regression. Children with ALL had sub-optimal bone mineral density (BMD) Z-score/height (mean ± standard error: - 0.53 ± 0.16 vs. 0.00 ± 0.14, p < 0.01), body mass index percentile (57.6 ± 3.15 vs. 50.0 ± 3.27%, p = 0.02), quadriceps strength (201.9 ± 8.3 vs. 236.1 ± 5.4 N, p < 0.01), 6 min walk distance (385.0 ± 13.1 vs. 628.2 ± 7.1 m, p < 0.001) and Bruininks-Oseretsky Test of Motor Proficiency scores (23 ± 2.5 vs. 50 ± 3.4%, p < 0.01). Quadriceps weakness was associated with a 20.9-fold (95% confidence interval 2.5-173.3) increase in poor physical HRQL. Children with newly diagnosed ALL have weakness and poor endurance and may benefit from early rehabilitation that includes strengthening and aerobic conditioning.