Measuring Habitual Physical Activity in Neuromuscular Disorders: A Systematic Review

Emerging methods for measuring physical activity using accelerometry in children and adolescents with neuromotor disorders: a narrative review

BACKGROUND

Children and adolescents with neuromotor disorders need regular physical activity to maintain optimal health and functional independence throughout their development. To this end, reliable measures of physical activity are integral to both assessing habitual physical activity and testing the efficacy of the many interventions designed to increase physical activity in these children. Wearable accelerometers have been used for children with neuromotor disorders for decades; however, studies most often use disorder-specific cut points to categorize physical activity intensity, which lack generalizability to a free-living environment. No reviews of accelerometer data processing methods have discussed the novel use of machine learning techniques for monitoring physical activity in children with neuromotor disorders.

METHODS

In this narrative review, we discuss traditional measures of physical activity (including questionnaires and objective accelerometry measures), the limitations of standard analysis for accelerometry in this unique population, and the potential benefits of applying machine learning approaches. We also provide recommendations for using machine learning approaches to monitor physical activity.

CONCLUSIONS

While wearable accelerometers provided a much-needed method to quantify physical activity, standard cut point analyses have limitations in children with neuromotor disorders. Machine learning models are a more robust method of analyzing accelerometer data in pediatric neuromotor disorders and using these methods over disorder-specific cut points is likely to improve accuracy of classifying both type and intensity of physical activity. Notably, there remains a critical need for further development of classifiers for children with more severe motor impairments, preschool aged children, and children in hospital settings.

A Wrinkle in Measuring Time Use for Cognitive Health: How should We Measure Physical Activity, Sedentary Behaviour and Sleep?

One new case of dementia is detected every 4 seconds and no effective drug therapy exists. Effective behavioural strategies to promote healthy cognitive ageing are thus essential. Three behaviours related to cognitive health which we all engage in daily are physical activity, sedentary behaviour and sleep. These time-use activity behaviours are linked to cognitive health in a complex and dynamic relationship not yet fully elucidated. Understanding how each of these behaviours is related to each other and cognitive health will help determine the most practical and effective lifestyle strategies for promoting healthy cognitive ageing. In this review, we discuss methods and analytical approaches to best investigate how these time-use activity behaviours are related to cognitive health. We highlight four key recommendations for examining these relationships such that researchers should include measures which (1) are psychometrically appropriate; (2) can specifically answer the research question; (3) include objective and subjective estimates of the behaviour and (4) choose an analytical method for modelling the relationships of time-use activity behaviours with cognitive health which is appropriate for their research question.

How is Physical Activity Measured in Spinal Muscular Atrophy and Duchenne Muscular Dystrophy?

BACKGROUND

Physical activity (PA) provides many substantial benefits to help reduce risk for cardiometabolic disease, improve cognitive function, and improve quality of life. Individuals with neuromuscular disorders (NMDs), such as spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD) are characterized by muscular weakness and fatigue, which limits the capacity to reach the recommended guidelines of PA. Measuring PA in these populations can provide insight to participation in daily activities, track disease progression, and monitor efficacy of drug treatments.

OBJECTIVE

The objective of this study was to identify how PA is measured in SMA and DMD using instrumented and self-report methods, and how these methods are employed in ambulatory and non-ambulatory groups.

METHODS

A scoping review was performed to identify studies that reported PA in these neuromuscular disorders. Inclusion was determined after a multi-stage review process by several reviewers, followed by an in-depth analysis of metrics reported by each tool that was used.

RESULTS

A total of nineteen studies were identified and included in this review. Sixteen studies included instrumented measures and four studies utilized self-reported measures, with eleven studies also reporting PA information from a non-ambulatory group. A variety of metrics have been reported using both classes of measurement tools.

CONCLUSION

Although a wide variety of research exists that details both instrumented and self-reported measurement tools, feasibility, cost, and study aims are important factors to consider in addition to testing methodology when selecting which type of tool to use. We recommend using a combination of instrumented and self-report measures to provide context to the PA measured in these populations. Improvements in both instrumented and self-report methodologies will add valuable knowledge about the disease burden and efficacy of treatment and disease management methods in SMA and DMD.

Validity of Fitbit activity monitoring for adults with progressive muscle diseases

PURPOSE

Measuring physical activity informs activity recommendations in clinical practice and provides outcomes in clinical trials that are meaningful to patients. Activity assessment in muscle disease is challenging and there is insufficient evidence to support any single activity measure; however, multi-modal activity measurement might have potential.

MATERIALS AND METHODS

This two-part study included 20 and 95 adults with progressive muscle diseases with mobility ranging from independent to assisted, including wheelchair users. Their activity was measured using a multi-sensor Fitbit activity monitor, for which criterion validity and acceptability were tested in study 1 and validity, reliability, and responsiveness were tested in the longitudinal, home-based study 2.

RESULTS

Study 1: Fitbit was acceptable and had strong criterion validity (rho/kappa ≥0.90), although up to 15% measurement error. Study 2: Fitbit had satisfactory concurrent and construct validity, reliability, and responsiveness. However, Fitbit active minutes registered 75 min more activity per week than gold standard moderate and vigorous physical activity (MVPA) time.

CONCLUSIONS

Fitbit had satisfactory measurement properties for monitoring physical activity in adults with progressive muscle diseases. However, Fitbit should not be considered an exact step counter, heart rate monitor or calorimeter and Fitbit active minutes are not synonymous with MVPA time.Implications for rehabilitationPeople with progressive muscle diseases mobilise independently, with walking aids and with wheelchairs; physical activity measurement can be challenging in this population.Multisensor smart activity monitoring by Fitbit had satisfactory validity, reliability, responsiveness, and acceptability for the estimation of physical activity in adults with progressive muscle diseases.Fitbit active minutes are not synonymous with moderate and vigorous physical activity (MVPA) time measured using a research grade accelerometer.

The validity of the International Physical Activity Questionnaire (IPAQ) for adults with progressive muscle diseases

PURPOSE

Measuring the physical activity of adults with progressive muscle diseases is important to inform clinical practice, for activity recommendations and for outcomes meaningful to participants in clinical trials. Despite its wide use, the measurement properties of the International Physical Activity Questionnaire (IPAQ) have not been established in a muscle disease population.

MATERIALS AND METHODS

The sample of 103 adults with progressive muscle diseases included independently mobile participants and wheelchair users. Their home-based activity measured by the IPAQ was compared to simultaneous weeks of accelerometer activity data collected remotely in a longitudinal, measure evaluation study. Validity, reliability, and responsiveness were evaluated for the IPAQ alone, and for the IPAQ used in conjunction with a smart activity monitor.

RESULTS

The IPAQ did not demonstrate satisfactory criterion validity, reliability or responsiveness and it systematically overestimated moderate and vigorous physical activity time by 161 minutes per week. Measurement properties of the IPAQ were improved when it was used in combination with a smart activity monitor.

CONCLUSIONS

The IPAQ did not have satisfactory measurement properties compared to accelerometry in adults with progressive muscle disease. Combining self-report and objective activity measures might improve the accuracy of physical activity assessment in this and other comparable populations.Implications for RehabilitationPhysical activity is a meaningful health outcome for adults with progressive muscle diseases, for whom precise activity quantification is important because of the potential for activity-related disease exacerbation.The International Physical Activity Questionnaire (IPAQ) had unsatisfactory measurement properties compared to accelerometry; however, these were improved by adjunctive smart activity monitoring.Objective or combined physical activity measurement is recommended over self-report alone for clinical assessment of physical activity as part of rehabilitation and self-management programmes.

Objective and subjective measures of sleep in men with Muscular Dystrophy

Purpose

Despite poor sleep quality being recognised in Duchenne Muscular Dystrophy, reports from milder forms of Muscular Dystrophy (MD), and accompanied associations with quality of life (QoL), pain and fatigue, remain limited however.

Methods

Adult males (n = 15 Beckers MD (BMD), n = 12 Limb-Girdle MD (LGMD), n = 12 Fascioscapulohumeral (FSHD), n = 14 non-MD (CTRL)) completed assessments of body composition (Bio-electrical impedance), sleep (7-day 24-hour tri-axial accelerometer, Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index, QoL (SF36-v2), pain (Visual analogue scale), fatigue (Modified Fatigue Index Scale) and functional assessments (Brookes and Vignos).

Results

FSHD and BMD reported worse sleep than CTRL on the PSQI. FSHD scored worse than CTRL on the Insomnia Severity Index (P<0.05). 25–63% and 50–81% of adults with MD reported poor sleep quality using the Insomnia Severity Index and PSQI, respectively. Accelerometery identified no difference in sleep quality between groups. Associations were identified between sleep measures (PSQI global and insomnia severity) with mental or physical QoL in LGMD, BMD and FSHD. Multiple regression identified associations between sleep impairment and fatigue severity (all MDs), body composition (BMD & LGMD), upper and lower limb function (LGMD, FSHD) and age (FSHD).

Conclusions

25–81% of men with MD, depending on classification, experience sleep impairment, using self-report sleep measures. Whilst BMD and FSHD showed worse sleep outcomes than CTRL, no group difference was observed between LGMD and CTRL, however all groups showed associations with sleep impairment and higher levels of fatigue. These findings, and associations with measures of health and wellbeing, highlight an area for further research which could impact QoL in adults with MD.

Physical and Functional Clinical Profile of Older Adults in Specialized Geriatric Rehabilitation Care Services in Saguenay-Québec: A Retrospective Study at La Baie Hospital

Musculoskeletal disorders, cardiovascular and neurological diseases were the most commonly debilitating conditions and risk factors associated with pain, mobility limitations, increased risk of falls and disability. Studies barely address the profile of older adults in care within a specialized geriatric rehabilitation service (SGRS) to provide subsidies for new actions within the public healthcare to reduce falls and improve management in health investments. This study aimed to establish a clinical physical and functional profile of the patients with neuromusculoskeletal and cognitive disorders and fallers in interventions within SGRS. From a retrospective study design, 127 medical records were compiled and analyzed to determine the physical and functional profile of older adults and differences according to sex, age groups and the benefits for local physical therapy intervention. The users were between 76 and 85 years of age, with diverse clinical diagnoses and debilitating conditions and impairments. A higher proportion presented gait and balance impairments and had two or more falls in 12 months. A significant effect for advanced age was observed. Overall, real benefits were reported with intervention for functional improvement, although the absence of a control group. These results have direct implications for a better understanding of a local SGRS and provide subsidies for developing new approaches for the assessment and treatment of older adults with high a risk of falls in order to reduce costs for the public health system.

Surface Electromyography Thresholds as a Measure for Performance Fatigability During Incremental Cycling in Patients With Neuromuscular Disorders

In healthy persons, there is an excellent relation between the timing of the (two) surface electromyography (sEMG) thresholds and the (two) ventilatory thresholds during exercise. The primary aim of this study was to determine the relative timing of both sEMG and ventilatory thresholds in patients with neuromuscular disorders compared with healthy subjects during a maximal ergospirometry cycling test. We hypothesized that in patients with neuromuscular disorders, the sEMG thresholds would occur relatively earlier in time than the ventilatory thresholds, compared to healthy subjects, because performance fatigability occurs more rapidly. In total, 24 healthy controls and 32 patients with a neuromuscular disorder performed a cardiopulmonary exercise test on a bicycle using a 10-min ramp protocol, during which we collected ergospirometry data: power at both ventilatory and sEMG thresholds, and sEMG data of lower leg muscles. In line with our hypothesis, normalized values for all thresholds were lower for patients than healthy subjects. These differences were significant for the first ventilatory (p = 0.008) and sEMG threshold (p &lt; 0.001) but not for the second sEMG (p = 0.053) and ventilatory threshold (p = 0.238). Most parameters for test–retest reliability of all thresholds did not show any fixed bias, except for the second ventilatory threshold. The feasibility of the sEMG thresholds was lower than the ventilatory thresholds, particularly of the first sEMG threshold. As expected, the sEMG thresholds, particularly the first threshold, occurred relatively earlier in time than the ventilatory thresholds in patients compared with healthy subjects. A possible explanation could be (a combination of) a difference in fiber type composition, disuse, and limited muscle-specific force in patients with neuromuscular disorders. sEMG measurements during submaximal dynamic exercises are needed to generalize the measurements to daily life activities for future use in prescribing and evaluating rehabilitation interventions.

Functional Ability and Physical Activity in Hereditary Neuromuscular Diseases

BACKGROUND

Physical activity may help to promote health in patients with Limb-girdle muscular dystrophy (LGMD) and Charcot-Marie-Tooth disease (CMT).

OBJECTIVE

To investigate associations between functional ability and other variables, with physical activity in people with LGMD and CMT grouped according to the International Classification of Functioning, Disability, and Health (ICF).

METHODS

We did a cross-sectional study, recruiting respondents from the Norwegian registry of inherited neuromuscular disorders. We used the Norwegian version of Barthel index of Activities of Daily Living (ADL) to measure functional ability and the International Physical Activity Questionnaire -short form (IPAQ-sf) to classify physical activity. We used multivariable logistic regression analysis to investigate associations between variables.

RESULTS

145 subjects were recruited (79 with CMT and 66 with LGMD). 55.6% of the subjects met a minimum recommendation of physical activity. Participants with moderate to severe functional ability were more likely to be physically inactive compared to those with normal functional ability (OR 19.7; 95% CI 3.1-127.2). Mildly decreased functional ability also showed higher odds of being physically inactive compared to participants with normal functional ability (OR 4.1; 95% CI 1.1-15.6). Higher education was associated with inactivity. Fatigue, participation in physiotherapy, and participation in adapted physical activity programs were not associated with physical activity.

CONCLUSIONS

Low functional ability was associated with physical inactivity in both LGMD and CMT. Association between higher education and inactivity might indicate the need to provide more understanding about physical activity benefit in this group.

Stride Velocity 95th Centile: Insights into Gaining Regulatory Qualification of the First Wearable-Derived Digital Endpoint for use in Duchenne Muscular Dystrophy Trials

In 2019, stride velocity 95th centile (SV95C) became the first wearable-derived digital clinical outcome assessment (COA) qualified by the European Medicines Agency (EMA) for use as a secondary endpoint in trials for Duchenne muscular dystrophy. SV95C was approved via the EMA’s qualification pathway for novel methodologies for medicine development, which is a voluntary procedure for assessing the regulatory acceptability of innovative methods used in pharmaceutical research and development. SV95C is an objective, real-world digital ambulation measure of peak performance, representing the speed of the fastest strides taken by the wearer over a recording period of 180 hours. SV95C is correlated with traditional clinic-based assessments of motor function and has greater sensitivity to clinical change over 6 months than other wearable-derived stride variables, for example, median stride length or velocity. SV95C overcomes many limitations of episodic, clinic-based motor function testing, allowing the assessment of ambulation ability between clinic visits and under free-living conditions. Here we highlight considerations and challenges in developing SV95C using evidence generated by a high-performance wearable sensor. We also provide a commentary of the device’s technical capabilities, which were a determining factor in the regulatory approval of SV95C. This article aims to provide insights into the methods employed, and the challenges faced, during the regulatory approval process for researchers developing new digital tools for patients with diseases that affect motor function.

Quantitative assessment of sitting time in ambulant adults with Muscular Dystrophy

BACKGROUND

Current investigations into physical behaviour in Muscular Dystrophy (MD) have focussed largely on physical activity (PA). Negative health behaviours such as sedentary behaviour (Physical Behaviour) and sitting time (Posture Classification) are widely recognised to negatively influence health, but by contrast are poorly reported, yet could be easier behaviours to modify.

METHODS

14 ambulant men with MD and 12 healthy controls (CTRL) subjects completed 7-days of free-living with wrist-worn accelerometry, assessing physical behaviour (SB or PA) and Posture Classification (Sitting or Standing), presented at absolute (minutes) or relative (% Waking Hours). Participant body composition (Fat Mass and Fat Free Mass) were assessed by Bioelectrical Impedance, while functional status was assessed by 10 m walk test and a functional scale (Swinyard Scale).

RESULTS

Absolute Sedentary Behaviour (2.2 Hours, p = 0.025) and Sitting Time (1.9 Hours, p = 0.030 was greater in adults with MD compared to CTRL and Absolute Physical Activity (3.4 Hours, p < 0.001) and Standing Time (3.2 Hours, p < 0.001) was lower in adults with MD compared to CTRL. Absolute hours of SB was associated with Fat Mass (Kg) (R = 0.643, p < 0.05) in ambulatory adults with MD.

DISCUSSION

This study has demonstrated increased Sedentary Behaviour (2.2 hours) and Sitting time (1.9 Hours) in adults with MD compared to healthy controls. Extended waking hours in sitting and SB raises concerns with regards to progression of potential cardio-metabolic diseases and co-morbidities in MD.

Free-Living Physical Activity and Sedentary Behaviour in Autoimmune Myasthenia Gravis: A Cross-Sectional Study

BACKGROUND

Muscle weakness and fatigability, the prominent symptoms of autoimmune myasthenia gravis (MG), negatively impact daily function and quality of life (QoL). It is currently unclear as to what extent symptoms limit activity and whether physical activity (PA) behaviours are associated with reduced QoL.

OBJECTIVES

This study aimed to describe habitual PA patterns and explore relationships between PA metrics, clinical MG characteristics, and health-related QoL (HRQoL).

METHODS

PA data from a tri-axial trunk accelerometer worn for seven days, was collected from females with generalized, stable MG and compared to control subjects. MG-specific evaluations, the six-minute walk test and knee extension strength were assessed in individuals with MG (IwMG). Mann-Whitney tests were used to study between-group differences. Spearman rank correlation coefficient was performed to explore relationships between variables.

RESULTS

Thirty-three IwMG (mean (SD) age 45 (11) years) and 66 control subjects were included. IwMG perform less vigorous-intensity PA than control subjects (p = 0.001), spend more time sedentary (p = 0.02) and engage in less and shorter durations of moderate-vigorous-intensity PA (MVPA). For IwMG, habitual PA correlated positively with 6 min walking distance (rho = 0.387, p = 0.029) and negatively with body mass index (rho = -0.407, p = 0.019). We did not find any association between PA or sedentary behaviour and; HRQoL, symptom severity nor lower limb strength.

CONCLUSIONS

Individuals with stable MG perform less PA, at lower intensities, and are more inactive than control individuals. Further research is warranted to understand factors influencing PA patterns in MG and whether interventions could be successful in increasing PA quantity and intensity in IwMG.

Habitual Physical Activity in Patients with Myasthenia Gravis Assessed by Accelerometry and Questionnaire

BACKGROUND

Physical activity (PA) in patients with myasthenia gravis (MG) is considered safe and beneficial, and an active lifestyle is required to obtain the health benefits of exercise. However, as the disease leads to physical impairments an insight into the overall PA habits in this patient population is relevant but lacking.

OBJECTIVE

To measure habitual physical activity in a Danish cohort of patients with MG measured by accelerometer and questionnaire, and to determine relevant predictors for PA intensities.

METHODS

Habitual physical activity was assessed by; 1) the accelerometer Acti Graph in a cohort of patients recruited from our neuromuscular clinic, 2) the International Physical Activity Questionnaire (IPAQ) in a web-based survey. PA levels were compared to international recommendations. Predictors for PA (age, sex, body mass index, disease severity and duration) were included in the regression analyses.

RESULTS

Habitual physical activity was measured by accelerometer for 7 days in 69 patients and by questionnaire in 691 patients. Measured by the accelerometer, 46%of the patients did not meet the international recommendations for PA at moderate/vigorous intensity and 57%were below the recommendations for steps per day. Measured by the IPAQ, 48%did not meet the recommendations. Disease severity and age were predictors for PA intensities.

CONCLUSIONS

This study found that around half of the included patients did not meet the recommendations for PA. This is a concern, as it increases the risk of life-style related diseases. Disease severity and age may be taking into consideration when counseling the patients about PA.

Interventions for promoting physical activity in people with neuromuscular disease

BACKGROUND

The World Health Organization (WHO) recommends that people of all ages take regular and adequate physical activity. If unable to meet the recommendations due to health conditions, international guidance advises being as physically active as possible. Evidence from community interventions of physical activity indicate that people living with medical conditions are sometimes excluded from participation in studies. In this review, we considered the effects of activity-promoting interventions on physical activity and well-being in studies, as well as any adverse events experienced by participants living with inherited or acquired neuromuscular diseases (NMDs).  OBJECTIVES: To assess the effects of interventions designed to promote physical activity in people with NMD compared with no intervention or alternative interventions.

SEARCH METHODS

On 30 April 2020, we searched Cochrane Neuromuscular Specialised Register, CENTRAL, Embase, MEDLINE, and ClinicalTrials.Gov. WHO ICTRP was not accessible at the time.

SELECTION CRITERIA

We considered randomised or quasi-randomised trials, including cross-over trials, of interventions designed to promote physical activity in people with NMD compared to no intervention or alternative interventions. We specifically included studies that reported physical activity as an outcome measure. Our main focus was studies in which promoting physical activity was a stated aim but we also included studies in which physical activity was assessed as a secondary or exploratory outcome.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane procedures.

MAIN RESULTS

The review included 13 studies (795 randomised participants from 12 studies; number of participants unclear in one study) of different interventions to promote physical activity. Most studies randomised a minority of invited participants. No study involved children or adolescents and nine studies reported minimal entry criteria for walking. Participants had one of nine inherited or acquired NMDs. Types of intervention included structured physical activity support, exercise support (as a specific form of physical activity), and behaviour change support that included physical activity or exercise. Only one included study clearly reported that the aim of intervention was to increase physical activity. Other studies reported or planned to analyse the effects of intervention on physical activity as a secondary or exploratory outcome measure. Six studies did not report results for physical activity outcomes, or the data were not usable. We judged 10 of the 13 included studies at high or unclear risk of bias from incomplete physical activity outcome reporting. We did not perform a meta-analysis for any comparison because of differences in interventions and in usual care. We also found considerable variation in how studies reported physical activity as an outcome measure. The studies that reported physical activity measurement did not always clearly report intention-to-treat (ITT) analysis or whether final assessments occurred during or after intervention. Based on prespecified measures, we included three comparisons in our summary of findings. A physical activity programme (weight-bearing) compared to no physical activity programme One study involved adults with diabetic peripheral neuropathy (DPN) and reported weekly duration of walking during and at the end of a one-year intervention using a StepWatch ankle accelerometer. Based on the point estimate and low-certainty evidence, intervention may have led to an important increase in physical activity per week; however, the 95% confidence interval (CI) included the possibility of no difference or an effect in either direction at three months (mean difference (MD) 34 minutes per week, 95% CI -92.19 to 160.19; 69 participants), six months (MD 68 minutes per week, 95% CI -55.35 to 191.35; 74 participants), and 12 months (MD 49 minutes per week, 95% CI -75.73 to 173.73; 70 participants). Study-reported effect estimates for foot lesions and full-thickness ulcers also included the possibility of no difference, a higher, or lower risk with intervention. A sensor-based, interactive exercise programme compared to no sensor-based, interactive exercise programme One study involved adults with DPN and reported duration of walking over 48 hours at the end of four weeks' intervention using a t-shirt embedded PAMSys sensor. It was not possible to draw conclusions about the effectiveness of the intervention from the very low-certainty evidence (MD -0.64 hours per 48 hours, 95% CI -2.42 to 1.13; 25 participants). We were also unable to draw conclusions about impact on the Physical Component Score (PCS) for quality of life (MD 0.24 points, 95% CI -5.98 to 6.46; 35 participants; very low-certainty evidence), although intervention may have made little or no difference to the Mental Component Score (MCS) for quality of life (MD 5.10 points, 95% CI -0.58 to 10.78; 35 participants; low-certainty evidence). A functional exercise programme compared to a stretching exercise programme One study involved adults with spinal and bulbar muscular atrophy and reported a daily physical activity count at the end of 12 weeks' intervention using an Actical accelerometer. It was not possible to draw conclusions about the effectiveness of either intervention (requiring compliance) due to low-certainty evidence and unconfirmed measurement units (MD -8701, 95% CI -38,293.30 to 20,891.30; 43 participants). Functional exercise may have made little or no difference to quality of life compared to stretching (PCS: MD -1.10 points, 95% CI -5.22 to 3.02; MCS: MD -1.10 points, 95% CI -6.79 to 4.59; 49 participants; low-certainty evidence). Although studies reported adverse events incompletely, we found no evidence of supported activity increasing the risk of serious adverse events.

AUTHORS' CONCLUSIONS

We found a lack of evidence relating to children, adolescents, and non-ambulant people of any age. Many people living with NMD did not meet randomised controlled trial eligibility criteria. There was variation in the components of supported activity intervention and usual care, such as physical therapy provision. We identified variation among studies in how physical activity was monitored, analysed, and reported. We remain uncertain of the effectiveness of promotional intervention for physical activity and its impact on quality of life and adverse events. More information is needed on the ITT population, as well as more complete reporting of outcomes. While there may be no single objective measure of physical activity, the study of qualitative and dichotomous change in self-reported overall physical activity might offer a pragmatic approach to capturing important change at an individual and population level.

Self-reported physical activity in people with limb-girdle muscular dystrophy and Charcot-Marie-Tooth disease in Norway

BACKGROUND

Physical activity is associated with positive health effects, but individuals with neuromuscular disease (NMD) may experience constraints being physically active. There is a gap in the literature on the activity level of people with NMDs, and therefore we did a study to determine the physical activity level in people with Limb-Girdle muscular dystrophy (LGMD) and Charcot-Marie-Tooth disease (CMT).

METHODS

This study used a cross-sectional design to obtain self-reported physical activity and sitting time among individuals with LGMD and CMT who were recruited from the Norwegian registry for hereditary and congenital neuromuscular diseases.

RESULTS

A total of 127 respondents who filled out questionnaires about either physical activity or sitting time were included in the analysis. Seventy (55.1%) had a diagnosis of CMT and 57 (44.9%) had a diagnosis of LGMD. Seventy-three (57.5%) respondents were female and 54 (42.5%) were male. Among the 108 respondents with available physical activity data, 44.4% reported being physically inactive. Among the 109 respondents with available sitting time data, the average sitting time was 8.6 h. Longer sitting time was associated with higher physical inactivity.

CONCLUSION

Among people with LGMD and CMT in our study, 55.6% reported being physically active. Respondents with LGMD and CMT reported longer sitting time and less physical activity compared with healthy respondents in other studies. Further research should explore variables and measures that can promote physical activity among people with neuromuscular conditions.

Psychosocial impact of sport activity in neuromuscular disorders

Previous studies demonstrated the benefits of motor exercise and physical activity in neuromuscular disorders. However, very few papers assessed the effects of sport practise. The aim of this multicentre study was to assess the impact of sport activity on self-esteem and emotional regulation in a cohort of athletes with neuromuscular disorders. The 38 patients with Duchenne, Becker or other types of muscular dystrophy or spinal muscular atrophy practising sport (aged 13-49 years) and 39 age-, gender-, disability- and disease-matched patients not practising sport were enrolled. Testing procedures to assess self-esteem, anxiety and depression disorder, personality trait and quality of life (QoL) were used. Patients practising sport had a significantly higher self-esteem, lower level of depression, greater social own identity and adherence and QoL. Frequency of sport activity may represent a complementary therapy in neuromuscular disorders to improve mental and social well-being.

Long-term recording of electromyographic activity from multiple muscles to monitor physical activity of participants with or without a neurological disorder

Various portable monitors have been used to quantify physical activity but most rely on detecting limb movement with a sensor rather than measuring muscle activity. Our first goal was to design and validate a portable system for recording surface electromyographic activity (EMG) from eight muscles over 24 h. The modular system includes: (1) preamplifiers that filter and amplify signals; (2) a preprocessor unit for further filtering and amplification, signal offset and power supply modification; (3) a data-logger for analog-to-digital conversion; a flash memory card for data storage and (4) a rechargeable battery. The equipment samples EMG at 1000 Hz, has a resolution of 2.6 μV and records signals up to 10 mV. The built-in analog filters create a bandwidth appropriate for surface EMG. Our second aim was to test the system biologically by recording EMG from able-bodied and spinal cord injured participants. Modifications were made to electrodes for remote preamplifier placement, and to the battery connection after pilot testing. Thereafter, 31 consecutive 24-h EMG recordings were successful. Both the engineering and biological validation of this system establishes it as a valuable tool for measuring physical activity from different muscles in real-world environments whether individuals have an intact or damaged nervous system.

The International Classification of Functioning, Disability and Health-based factors related to physical activity level in adults with muscle diseases

The aim of this study was to investigate the physical activity (PA) level of adults with muscle diseases and the association of factors affecting PA behaviour. Forty-five adults with muscle diseases and 44 healthy participants were included. The PA was assessed by a SenseWear Armband and the International Physical Activity Questionnaire. The muscle strength, pain, fatigue severity, activity limitations, functional mobility level and quality of life were also assessed. Compared with the healthy group, adults with muscle diseases had significantly lower step counts and duration of moderate and vigorous PA (P < 0.05). The BMI of the patients was related to total energy expenditure (P < 0.05). The total number of steps, energy expenditure and duration of moderate PA of the patients were related to the 6-min walk test (P < 0.05). There was a correlation between total, moderate and vigorous PA and mental health in adults with muscle diseases (P < 0.05). The most important factors in reflecting PA in adults with muscle diseases are considered as BMI from personal factors, functional mobility from activity limitations and quality of life in the dimension of participation.

Natural variability of daily physical activity measured by accelerometry in children with a mitochondrial disease

In this exploratory study we aimed to select the most valid and feasible accelerometer to measure daily physical activity at home in 10 children with mitochondrial disease. Using the experimentally-selected GENEActiv, good to excellent short- and long-term test-retest reliability of daily physical activity was found. Especially in children with more severe limitations daily physical activity seemed more stable and less susceptible to weather conditions. Moreover, small standard errors of measurement were found, indicating high precision of this measuring method. We conclude that measuring daily physical activity using accelerometry is a promising outcome measure for future studies in this unique population.

[Which follow-up for innovative treatments?]

Suivre les bénéfices et la tolérance d’une thérapie innovante constitue un exercice relativement récent dans le champ des maladies neuromusculaires. Fonction respiratoire, capacités musculaires et fonctionnelles, qualité de vie, effets indésirables, pour chaque paramètre à évaluer s’esquisse un panel de mesures idéales.

Relationships between muscle size, strength, and physical activity in adults with muscular dystrophy

BACKGROUND

Muscular dystrophy (MD) is characterized by progressive muscle wasting and weakness, yet few comparisons to non-MD controls (CTRL) of muscle strength and size in this adult population exist. Physical activity (PA) is promoted to maintain health and muscle strength within MD; however, PA reporting in adults with MD is limited to recall data, and its impact on muscle strength is seldom explored.

METHODS

This study included 76 participants: 16 non-MD (CTRL, mean age 35.4), 15 Duchenne MD (DMD, mean age 24.2), 18 Becker's MD (BMD, mean age 42.4), 13 limb-girdle MD (LGMD, mean age 43.1), and 14 facioscapulohumeral MD (mean age 47.7). Body fat (%) and lean body mass (LBM) were measured using bioelectrical-impedance. Gastrocnemius medialis (GM) anatomical cross-sectional area (ACSA) was determined using B-mode ultrasound. Isometric maximal voluntary contraction (MVC) was assessed during plantar flexion (PFMVC) and knee extension (KEMVC). PA was measured for seven continuous days using triaxial accelerometry and was expressed as daily average minutes being physically active (TPAmins ) or average daily percentage of waking hours being sedentary (sedentary behaviour). Additionally, 10 m walk time was assessed.

RESULTS

Muscular dystrophy groups had 34-46% higher body fat (%) than CTRL. DMD showed differences in LBM with 21-28% less LBM than all other groups. PFMVC and KEMVC were 36-75% and 24-92% lower, respectively, in MD groups than CTRL. GM ACSA was 47% and 39% larger in BMD and LGMD, respectively, compared with CTRL. PFMVC was associated with GM ACSA in DMD (P = 0.026, R = 0.429) and CTRL (P = 0.015, R = 0.553). MD groups were 14-38% more sedentary than CTRL groups, while DMD were more sedentary than BMD (14%), LGMD (8%), and facioscapulohumeral MD (14%). Sedentary behaviour was associated with LBM in DMD participants (P = 0.021, R = -0.446). TPAmins was associated with KEMVC (P = 0.020, R = 0.540) in BMD participants, while TPAmins was also the best predictor of 10 m walk time (P < 0.001, R2  = 0.540) in ambulant MD, revealed by multiple linear regression.

CONCLUSIONS

Quantified muscle weakness and impaired 10 m walking time is reported in adults with MD. Muscle weakness and 10 m walk time were associated with lower levels of TPA in adults with MD. Higher levels of sedentary behaviour were associated with reduced LBM in DMD. These findings suggest a need for investigations into patterns of PA behaviour, and relevant interventions to reduce sedentary behaviour and encourage PA in adults with MD regardless of impairment severity.

Analyzing walking speeds with ankle and wrist worn accelerometers in a cohort with myotonic dystrophy

Background: Accelerometers are accurate tools to assess movement and physical activity. However, interpreting standardly used outputs is not straightforward for populations with impaired mobility.

Methods: The applicability of GENEActiv was explored in a group of 30 participants with myotonic dystrophy and compared to a group of 14 healthy-controls. All participants performed a set of tests while wearing four different accelerometers (wrists and ankles): [1] standing still; [2] ten-meters walk test; [3] six-minutes walking test; and, [4] ten-meters walk/run test.

Results: Relevant findings were: [1] high intra-accelerometer reliability (i.e. 0.97 to 0.99; p < 0.001); [2] each test acceleration values differ significantly between each other; [3] no inter-accelerometer reliability between wrist-worn devices and ankle-worn; and [4] a significant difference between the myotonic dystrophy group and the healthy-controls detectable at each test (i.e. Left-ankle values at six-minutes walking test: 48±17 for the myotonic dystrophy group, vs, 74±16 for the healthy-controls; p < 0.001).

Conclusions: GENEActiv demonstrated to be valid and reliable, capable of detecting walking periods and discriminating different speeds. However, inter-accelerometer reliability only applied when comparing opposite sides of the same limb. Specific movement characteristics of the myotonic dystrophy group were identified and muscle strength showed not to be a full determinant of limb acceleration.

Implications for rehabilitation

Rehabilitation professionals in the field of neuromuscular disorders should be aware of the potential use of objective monitoring tools such as accelerometers whilst acknowledging the implications of assessing populations with altered movement patterns.

Researchers should be cautious when translating accelerometry outputs previously validated in healthy populations to functionally impaired cohorts like myotonic dystrophy.

Accelerometers can objectively expose movement disturbances allowing further investigations for the source of these disturbances.

Update on outcome assessment in myositis

The adult and juvenile myositis syndromes, commonly referred to collectively as idiopathic inflammatory myopathies (IIMs), are systemic autoimmune diseases with the hallmarks of muscle weakness and inflammation. Validated, well-standardized measures to assess disease activity, known as core set measures, were developed by international networks of myositis researchers for use in clinical trials. Composite response criteria using weighted changes in the core set measures of disease activity were developed and validated for adult and juvenile patients with dermatomyositis and adult patients with polymyositis, with different thresholds for minimal, moderate and major improvement in adults and juveniles. Additional measures of muscle strength and function are being validated to improve content validity and sensitivity to change. A health-related quality of life measure, which incorporates patient input, is being developed for adult patients with IIM. Disease state criteria, including criteria for inactive disease and remission, are being used as secondary end points in clinical trials. MRI of muscle and immunological biomarkers are promising approaches to discriminate between disease activity and damage and might provide much-needed objective outcome measures. These advances in the assessment of outcomes for myositis treatment, along with collaborations between international networks, should facilitate further development of new therapies for patients with IIM.