Functional testing

Outcome Measures in Facioscapulohumeral Muscular Dystrophy Clinical Trials

Facioscapulohumeral muscular dystrophy (FSHD) is a debilitating muscular dystrophy with a variable age of onset, severity, and progression. While there is still no cure for this disease, progress towards FSHD therapies has accelerated since the underlying mechanism of epigenetic derepression of the double homeobox 4 (DUX4) gene leading to skeletal muscle toxicity was identified. This has facilitated the rapid development of novel therapies to target DUX4 expression and downstream dysregulation that cause muscle degeneration. These discoveries and pre-clinical translational studies have opened new avenues for therapies that await evaluation in clinical trials. As the field anticipates more FSHD trials, the need has grown for more reliable and quantifiable outcome measures of muscle function, both for early phase and phase II and III trials. Advanced tools that facilitate longitudinal clinical assessment will greatly improve the potential of trials to identify therapeutics that successfully ameliorate disease progression or permit muscle functional recovery. Here, we discuss current and emerging FSHD outcome measures and the challenges that investigators may experience in applying such measures to FSHD clinical trial design and implementation.

Nusinersen for older patients with spinal muscular atrophy: A real-world clinical setting experience

INTRODUCTION

Clinical trials data concerning use of nusinersen in older spinal muscular atrophy (SMA) patients is lacking. We describe our center's experience in using intrathecal nusinersen for older patients in the clinical setting.

METHODS

Retrospective study.

RESULTS

Twelve patients (12-52 years old) were treated with nusinersen. Mean follow-up duration was 17.4 months (range, 4-26 months). All patients had scoliosis; 10 had spinal fusion/instrumentation. All procedures (30 cervical and 57 lumbar punctures) were technically successful. The only side effects were postprocedural headache (9%) and site pain (5.7%). Functional assessments showed stability in 6/9 patients and improvement in 3/9 patients. Subjective improvements in endurance, hand strength, and bulbar functioning critical for activities of daily living were reported in 8/12 patients. None of the patients has discontinued treatment so far.

DISCUSSION

Intrathecal nusinersen can be safely delivered in older SMA patients. Available functional outcome measures are not adequate to capture meaningful subjective improvements.

Clinical trial readiness to solve barriers to drug development in FSHD (ReSolve): protocol of a large, international, multi-center prospective study

Background

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly-inherited progressive muscular dystrophy caused by de-repression of the DUX4 gene, which causes disease by a toxic-gain-of-function. As molecularly targeted drugs move from preclinical testing into human trials, it is essential that we validate clinical trial tools and methodology to facilitate the drug development process.

Methods/design

The primary goal of this study is to hasten drug development for FSHD by validating two novel clinical outcome assessments (COAs) and refining clinical trial strategies. We will perform an 18-month longitudinal study in 220 genetically confirmed and clinically affected participants using our FSHD Clinical Trial Research Network, comprised of 8 sites in the United States, and 3 collaborating sites in Europe. Visits occur at baseline and months 3, 12, and 18. At each visit we will collect: 1) a novel FSHD functional composite COA made up of 18 evaluator-administered motor tasks in the domains of shoulder/arm, hand, core/abdominal, leg, and balance function; and 2) electrical impedance myography as a novel muscle quality biomarker (US sites). Other COAs include 1) Domain 1 of the Motor Function Measure; 2) Reachable workspace; 3) orofacial strength using the Iowa Oral Performance Instrument; 4) lean muscle mass using dual-energy X-ray absorptiometry (DEXA); 5) strength as measured by quantitative myometry and manual muscle testing; and 6) the FSHD Health Index and other patient-reported outcomes. Plasma, DNA, RNA, and serum will be collected for future biomarker studies. We will use an industry standard multi-site training plan. We will evaluate the test-retest reliability, validity, and sensitivity to disease progression, and minimal clinically important changes of our new COAs. We will assess associations between demographic and genetic factors and the rate of disease progression to inform refinement of eligibility criteria for future clinical trials.

Discussion

To the best of our knowledge, this is the largest collaborative study of patients with FSHD performed in the US and Europe. The results of this study will enable more efficient clinical trial design. During the conduct of the study, relevant data will be made available for investigators or companies pursuing novel FSHD therapeutics.

Trial registration

clinicaltrials.gov NCT03458832; Date of registration: 1/11/2018

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1452-x) contains supplementary material, which is available to authorized users.

Assessing drug effect from distributional data: A population approach with application to Duchenne Muscular Dystrophy treatment

BACKGROUND AND OBJECTIVE

In Duchenne Muscular Dystrophy (DMD) treatment, muscle fiber size can be considered as an indicator of muscle health and function. In particular, the statistical distribution of fibers cross-sectional areas (CSAs) has been used as quantitative efficacy endpoint. For each patient, assessment of treatment effect relies on the comparison of pre- and post-treatment biopsies. Since biopsies provide "distributional data", i.e. empirical distributions of fibers CSA, the comparison must be carried out between the empirical pre- and post-treatment distributions.

METHODS

Here, distributional fiber CSA data are analyzed by means of a hierarchical statistical model based on the population approach, considering both the single patient and the population level.

RESULTS

The proposed method was used to assess the histological clinical effects of Givinostat, a compound under study for DMD treatment. At the single patient level, a two-component Gaussian mixture adequately represents pre- and post-treatment distributions of log-transformed CSAs; drug effect is described via a dose-dependent multiplicative increase of muscle fiber size. The single patient model was also validated via muscle composition data. At the patient population level, typical model parameters and inter-patient variabilities were obtained.

CONCLUSIONS

The proposed methodological approach completely characterizes fiber CSA distributions and quantifies drug effect on muscle fiber size, both at the single patient and at the patient population level. This approach might be applied also in other contexts, where outcomes measured in terms of distributional data are to be assessed.

Motor function performance in individuals with RYR1-related myopathies

Introduction

The objective of this study was to obtain a 6‐month natural history of motor function performance in individuals with RYR1‐ related myopathy (RYR1‐RM) by using the Motor Function Measure‐32 (MFM‐32) and graded functional tests (GFT) while facilitating preparation for interventional trials.

Methods

In total, 34 participants completed the MFM‐32 and GFTs at baseline and 6‐month visits.

Results

Motor deficits according to MFM‐32 were primarily observed in the standing and transfers domain (D1; mean 71%). Among the GFTs, participants required the most time to ascend/descend stairs (>7.5 s). Functional movement, determined by GFT grades, was strongly correlated with MFM‐32 (D1; r ≥ 0.770, P < 0.001). Motor Function Measure‐32 and GFT scores did not reflect any change in performance between baseline and 6‐month visits.

Discussion

The MFM‐32 and GFTs detected motor impairment in RYR1‐RM, which remained stable over 6 months. Thus, these measures may be suitable for assessing change in motor function in response to therapeutic intervention. Muscle Nerve60: 80–87, 2019

Commonly available outcome measures for use in Indian boys with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder. It is still an incurable disease and many clinical trials are going on to find the cure for this disease. There is a need for sensitive and reliable measures for detecting the disease progression. This manuscript focuses on reviewing the different outcome measures which can be used in the Indian DMD patients.

Facioscapulohumeral muscular dystrophy functional composite outcome measure

INTRODUCTION

We developed an evaluator-administered functional facioscapulohumeral muscular dystrophy composite outcome measure (FSHD-COM) comprising patient-identified areas of functional burden for future clinical trials.

METHODS

We performed a prospective observational study of 41 patients with FSHD at 2 sites. The FSHD-COM includes functional assessment of the legs, shoulders and arms, trunk, hands, and balance/mobility. We determined the test-retest reliability and convergent validity compared to established FSHD disease metrics.

RESULTS

The FSHD-COM demonstrated excellent test-retest reliability (intraclass correlation coefficient [ICC] 0.96; subscale ICC range, 0.90-0.94). Cross-sectional associations between the FSHD-COM and disease duration, clinical severity, and strength were moderate to strong (Pearson correlation coefficient range |0.51-0.92|).

DISCUSSION

The FSHD-COM is a disease-relevant, functional composite outcome measure suitable for future FSHD clinical trials that shows excellent test-retest reliability and cross-sectional associations to disease measures. Future directions include determining multisite reliability, sensitivity to change, and the minimal clinically important change in the FSHD-COM. Muscle Nerve, 2018.

Reliability of the adult myopathy assessment tool in individuals with myositis

OBJECTIVE

The Adult Myopathy Assessment Tool (AMAT) is a 13-item performance-based battery developed to assess functional status and muscle endurance. The purpose of this study was to determine the intrarater and interrater reliability of the AMAT in adults with myositis.

METHODS

Nineteen raters (13 physical therapists and 6 physicians) scored videotaped recordings of patients with myositis performing the AMAT for a total of 114 tests and 1,482 item observations per session. Raters rescored the AMAT test and item observations during a followup session (mean ± SD 19 ± 6 days between scoring sessions). All raters completed a single, self-directed, electronic training module prior to the initial scoring session.

RESULTS

Intrarater and interrater reliability correlation coefficients were ≥0.94 for the AMAT functional subscale, endurance subscale, and total score (all P < 0.02 for Ho , ρ ≤0.75). All AMAT items had satisfactory intrarater agreement (kappa statistics with Fleiss-Cohen weights, with values κw = 0.57-1.00). Interrater agreement was acceptable for each AMAT item (κ = 0.56-0.89) except the sit up (κ = 0.16). The standard error of measurement and 95% confidence interval range for the AMAT total scores did not exceed 2 points across all observations (AMAT total score range 0-45).

CONCLUSION

The AMAT is a reliable, domain-specific assessment of functional status and muscle endurance for adult subjects with myositis. Results of this study suggest that physicians and physical therapists may reliably score the AMAT following a single training session. The AMAT functional subscale, endurance subscale, and total score exhibit interrater and intrarater reliability suitable for clinical and research use.

Reliability of the Modified Hammersmith Functional Motor Scale in young children with spinal muscular atrophy

INTRODUCTION

The test-retest reliability of the Modified Hammersmith Functional Motor Scale (MHFMS) in children with spinal muscular atrophy (SMA) ≤30 months of age was assessed. The age at which typically developing children (TD) achieve maximum MHFMS scores was also studied.

METHODS

Twenty-two children with SMA type II [mean age (SD) = 20 (5) months, range 9-30 months) were tested twice using the MHFMS. Twenty-five TD children [mean age (SD) = 18 (7) months, range 9-30 months) were tested once.

RESULTS

The average difference between MHFMS scores for SMA children was 0.18 [first assessment: mean (SD) = 12.8 (9.8); second assessment: mean (SD) = 13.0 (8.8)]. Reliability was excellent (ICC(1,3) = 0.96, SEM 1.86). TD participants had MHFMS scores ranging from 36 to 40 [mean (SD) = 39.2 (1.2)] and achieved maximum test scores at 12 months of age.

DISCUSSION

MHFMS scores in young children with SMA type II showed excellent test-retest stability. This suggests that the MHFMS can be used reliably in this younger population for clinical trials and follow-up.

Limb girdle muscular dystrophy: an interval study of weakness and functional impairment

OBJECTIVE

Prospective studies of the natural history of a myopathy are effective means of measuring the status and progression of disease. This 10-year interval study of progressive weakness and functional decline was aimed to document the natural course of clinically well-characterized limb girdle muscular dystrophy in South Africa.

METHODS

The manual muscle test (MMT) was used to evaluate limb strength; global strength was measured by the average muscle score (AMS). A nonlinear functional grading system was used to measure impairment of the arms and legs. An activities of daily living (ADL) scale was used to assess disability across multiple functional domains in a home environment.

RESULTS

The mean AMS deteriorated from 5.9 to 4.9 (on a 10-point scale) and was unrelated to patient age and disease duration. Most (78%) patients lost arm function. All patients maintained useful hand function. Two thirds of patients lost leg function. Half of the patients were wheelchair bound, and they reached this level of function around the end of their fourth decade of life. Every patient showed functional deterioration on the ADL scale. The mean score worsened from 65.6 to 77.2 (out of 156 points). The disability change was most pronounced in patients who became wheelchair bound.

CONCLUSION

This interval analysis showed a significant decline of limb strength that was independent of patient age or duration of disease and was more rapid in stronger patients. A functional grading system detected decline and was a useful measure of deterioration when applied to patients over intervals. An ADL assessment ascertained a significant functional decline across multiple functional domains in a home environment and allowed us to advise patients on compensatory strategies to limit dependence.

A modified Hammersmith functional motor scale for use in multi-center research on spinal muscular atrophy

The Hammersmith functional motor scale for children with spinal muscular atrophy was modified to establish a standard measure of functional ability in children with non-ambulant spinal muscular atrophy types 2 and 3 in a longitudinal multi-center clinical trial. This study assessed the intra- and interrater reliability and the test-retest stability of a modified version of the scale. Both intra- and interrater reliability were established. Results indicate that the scale is reliable and stable over a 6 month period. Reliability was maintained when patient sample criteria were expanded to include children younger than 30 months and children with popliteal angles greater than 20 degrees . These data establish the modified Hammersmith functional motor scale for children with spinal muscular atrophy as a reliable instrument for use in multi-center treatment trials in non-ambulant spinal muscular atrophy children. Our data provides additional support for the use of original scale items in terms of ease of administration, usefulness and reliability, while incorporating modifications to optimize its use in a multi-center clinical research setting.

Experimental protocol for the kinematic analysis of the hand: definition and repeatability

A quantitative and objective method based on the optoelectronic kinematic analysis of hand segments and on the calculation of global and partial parameters, which provide measures of the degree of long finger and thumb extension is proposed for the evaluation of the hand's voluntary range of motion and maximal opening of the fingers and thumb. To test the precision and repeatability of the method, the protocol was applied on 14 healthy subjects (28 hands). The proposed parameters are repeatable and show a precision between 5.5 degrees and 10.4 degrees (mean value: 7.3 degrees), comparable to values obtained with other methods. Advantages of the present approach include simultaneous analysis of all fingers, absence of cumbersome connecting cables and no need for individually customized devices. The method, also applied to the paretic hands of two hemiplegic stroke patients before and after electrical stimulation of the wrist and finger extensor muscles, has shown encouraging results for its clinical feasibility and utility in addition to functional tests.

Joint range of motion limitations in children and young adults with spinal muscular atrophy

OBJECTIVES

To elicit descriptive data about limited joint range of motion (ROM) in subjects with type II or III spinal muscular atrophy (SMA) and to examine the relation between the number of motions with limited range and both age and functional ability.

DESIGN

Descriptive cross-sectional study.

SETTING

Neurologic pediatric outpatient clinic at a hospital in Taiwan.

PARTICIPANTS

Twenty-seven subjects with SMA type II (mean age, 9.8+/-6.5y) and 17 with SMA type III (mean age, 12.2+/-8.7y). Intervention Measurement with transparent goniometers of joint ROM bilaterally of the shoulder, elbow, wrist, hip, knee, and ankle.

MAIN OUTCOME MEASURES

The proportion of participants with each ROM limitation compared with all participants with the same SMA type, age distribution of the participants with each ROM limitation, mean range loss of each motion limitation, and the contracture index (risk index of joint contracture).

RESULTS

Eighty-nine percent of the participants with SMA type II experienced knee extension limitation. Approximately 50% of the participants with both types of SMA had ankle dorsiflexion limitation. The motions of knee and hip extension and ankle dorsiflexion also had a relatively high contracture index. The number of motions with limited range positively correlated ( P <.001) with age and upper-extremity functional grade (the higher the functional grade, the poorer the functional ability) for SMA type II.

CONCLUSIONS

We found varying degrees of joint ROM limitation. Certain motions were noted to be high risks for the development of contractures. This risk was higher mostly in younger children.

Quantitative motor assessment in myotonic dystrophy

OBJECTIVE

To establish baseline data, using a quantitative motor evaluation protocol, prior to a prospective longitudinal study of the natural history of muscular involvement in myotonic dystrophy (DM).

DESIGN/METHODS

We conducted a cross-sectional study using a protocol consisting of manual muscle testing (MMT), quantitative muscle testing (QMT), and timed functional testing (TFT) on 50 definite DM patients (27 men, 23 women), aged 16 to 67 years. The relationships between MMT, QMT and TFT scores and disease duration were examined using linear regression analysis.

RESULTS

The muscle weakness was symmetric and the neck flexors and the distal muscles of upper and lower extremities were weaker than proximal muscles. Using MMT scores, the average strength decline was 0.95% per year and was similar for men and women. The strength decline was significantly more rapid for distal muscles than for proximal muscles. Quantitative muscle testing scores documented a strength decline per year of disease duration of 1.2-1.6% for the hip flexors and of 2.0-3.0% for the hand grip flexors.

CONCLUSIONS

We observed significant linear relationships between the scores generated by this protocol and disease duration. These data illustrate the distal to proximal progression of muscular involvement in DM, a pattern of progression well-recognized by the clinicians. The follow-up assessment of a large DM cohort in a longitudinal study will establish whether this quantitative protocol provides sensitive measures of the disease progression.

Outcome assessment in the adult and juvenile idiopathic inflammatory myopathies

Through the recent efforts of multi-center collaborative study groups, a number of measures have been developed and partially validated to assess disease activity, disease damage, and health-related quality of life in adult and juvenile patients with IIM. Preliminary core set domains and core set measures of activity and damage have also been developed for adult and juvenile patients with myositis. Validated definitions of improvement and disability should be forthcoming in the next few years. These extraordinary developments will enable much-needed standardization in the assessment of the IIM, particularly in therapeutic and other clinical research studies. Despite this substantial progress, there is a need to develop more sensitive measures to assess IIM disease activity and damage, to further validate the existing tools, to define their performance characteristics in various IIM subgroups, to develop improved imaging techniques that are also quantitative, and to validate activation markers as surrogate measures. The ongoing cooperation of multiple specialists with expertise in these disorders, combined with emerging novel technologies, should continue to enhance the assessment of myositis. Improved clinical care and more rapid development of new therapies for patients with myositis will be the ultimate gains realized from these efforts.

Quadriceps strength and timed motor performances in myotonic dystrophy, Charcot-Marie-Tooth disease, and healthy subjects

BACKGROUND AND PURPOSE

The leading hypothesis was that a relation exists between muscular strength and functional abilities. Therefore a study was undertaken to quantify such a relationship in a population of subjects with different muscular strengths. This population consisted of healthy subjects and subjects with slowly progressive neuromuscular disorders.

METHODS

The study included 33 patients with myotonic dystrophy, 29 patients with Charcot-Marie-Tooth disease and 20 healthy subjects. Isokinetic and isometric knee torques were measured on an isokinetic dynamometer at various velocities. The following activities were timed: descending and ascending stairs, rising from a chair, rising from supine, walking at natural speed and walking at maximum speed.

RESULTS

The population covered a wide range of the variables: whereas the healthy subjects performed best (i.e. had the highest knee torques and performed the activities most quickly), the myotonic dystrophy group included the subjects with the lowest knee torques. The natural logarithms (In) of isokinetic extension torque at the highest velocity (120 degrees/s) and those of the time taken to perform the described activities showed the highest levels of correlation. It was found that after correction for age and weight, 56% (walking at natural speed) to 73% (descending stairs) of the variance in the In of the time taken could be attributed to the variance in the In of the torques.

CONCLUSION AND DISCUSSION

A strong relation between quadriceps strength and timed motor performances were demonstrated. The impact of strength reduction on time taken was most obvious in subjects with considerably decreased strength. Therefore, it is feasible to try to influence muscle strength in patients with relevant strength reduction in order to achieve better functional ability.

Limb girdle muscular dystrophy: a prospective follow-up study of functional impairment

This 6-year prospective follow-up study evaluated the rate of clinical disease progression in 19 of 20 previously reported patients with strictly selected limb girdle muscular dystrophy. There was no significant deterioration in muscle strength (assessed by manual muscle testing). An activities of daily living (ADL) scale showed significant functional deterioration in 30% of patients with predominant involvement in a single functional domain variable between patients, and determined by the patient's previous level of function. A functional grading system showed that 70% of patients had deteriorated at least one grade in the arms and/or legs. Deterioration of the ADL score correlated with the loss of functional grades. We conclude that assessment of functional ability may be more sensitive to detect clinical disease progression compared to testing of muscle strength. The clinical parameter that correlates best with the activity of the underlying disease process is not determined. Tests for strength and functional impairment are complementary. Patients expressed appreciation that functional disability was addressed during follow-up visits.

Strength training in patients with myotonic dystrophy and hereditary motor and sensory neuropathy: a randomized clinical trial

A randomized clinical trial on the effects of strength training was performed in myotonic dystrophy (MyD) patients and patients with hereditary motor and sensory neuropathy (HMSN). Training and most measurement tools involved the proximal lower extremity muscles. The participants trained 3 times a week for 24 weeks with weights adapted to their force. Strength was evaluated by isokinetically measured knee torque. Fatiguability was assessed by the time an isometric contraction could be sustained. Functional performance was measured by timed motor performance and by questionnaires on functional performance. Serum myoglobin (Mb) levels were determined to detect changes in muscle fiber membrane permeability. The MyD group included 33 participants, and the HMSN group included 29 participants. Within each diagnostic group, patients were individually matched and subsequently randomized for treatment allocation. In the MyD patients, none of the measurement techniques showed any training effect. Neither were there signs of deterioration caused by the training. In the HMSN group, knee torques increased. Timed motor performance did not change, although the questionnaires showed an improvement on items related to upper-leg function. Mb levels did not change significantly as a result of the training. In conclusion, the MyD group showed neither positive nor negative effects of the training protocol, whereas the training produced a moderate increase in strength and leg-related functional performance in the HMSN group.

Limb girdle muscular dystrophy: weakness and disease duration as predictors of functional impairment

This cross-sectional study compared progressive weakness to functional disability in 20 patients with limb girdle muscular dystrophy. Weakness (assessed by manual muscle testing) determined disability (assessed by functional grades, timed functional tests, and an activities of daily living scale). For any functional grade the degree of weakness varied between patients. Yet, at a certain "threshold" weakness the functional level predictably deteriorated. Change in functional grade did not reflect a parallel increase in weakness nor disease progression. Functional "milestones" were reached at varying durations of disease. Only guidelines were offered to individual patients as to the time course of progression in disability. Serial timed tests should be a sensitive, objective method to follow the rate of disease progression. Timely referral of patients to establish physical needs should delay functional deterioration and minimize handicap despite progressive weakness.

Isokinetic muscle testing (IMT) in neuromuscular diseases. Preliminary report

Isokinetic muscle testing (IMT) allows precise and reliable measurement of the force produced by the skeletal muscle during exercise at constant velocity and accommodating resistance. This study reports on some clinical situations that illustrate the difference between manual muscle testing (MMT) and IMT in neuromuscular patients. IMT was performed by a special method (continuous passive motion plus gravity compensation) which allowed the measurement of very weak forces, such as in the four patients described in this study. It is important to note that for the same MMT grading the corresponding isokinetic force values were very different. Therefore there is an obvious correspondence between the isokinetic measurement of muscle strength and the morphological change in the muscle on the CT scan of the thigh, which did not show up on MMT. IMT could be extremely important for research into neuromuscular disorders, where the detection of even the tiniest variations in strength is relevant.