Outcome measures in neuromuscular disease: is the world still flat?

Muscle ultrasound in hereditary muscle disease

In this review we summarise the key techniques of muscle ultrasound as they apply to hereditary muscle disease. We review the diagnostic utility of muscle ultrasound including its role in guiding electromyography and muscle biopsy sampling. We summarize the different patterns of sonographic muscle involvement in the major categories of genetic muscle disorders and discuss the limitations of the technique. We hope to encourage others to adopt ultrasound in their care for patients with hereditary muscle diseases.

International Delphi Recommendations for Pediatric Lower Limb Neurological Test Protocols for Muscle Strength, Reflexes, and Tactile Sensitivity

PURPOSE

To gain consensus from physical therapists on pediatric lower limb neurological tests of muscle strength, tactile sensitivity, and reflexes.

METHODS

A Delphi technique was used for 2 sequential questionnaire rounds to gain consensus from a panel of pediatric physical therapists (n = 28). Physical therapists rated their agreement to items from statements on pediatric lower limb neurological tests, their protocols, and interpretation using a 6-point Likert scale.

RESULTS

Ninety percent of items gained consensus: 80% on pediatric lower limb neurological tests, 88% on test protocols, and 92% on test interpretation. Fifty-one percent of items had high agreement and high importance.

CONCLUSION

There is variability in pediatric neurological tests used, their protocols, and interpretation. Identification of items with high agreement and importance is the first step to develop a standardized lower limb neurological assessment for pediatric clients of varying ages and diagnoses.

Guillain-Barré syndrome in low-income and middle-income countries: challenges and prospects

The epidemiology, clinical characteristics, management and outcome of Guillain-Barré syndrome (GBS) differ between low-income and middle-income countries (LMIC) and high-income countries (HIC). At present, limited data are available on GBS in LMIC and the true incidence of GBS in many LMIC remains unknown. Increased understanding of GBS in LMIC is needed because poor hygiene and high exposure to infections render populations in LMIC vulnerable to GBS outbreaks. Furthermore, insufficient diagnostic and health-care facilities in LMIC contribute to delayed diagnosis in patients with severe presentations of GBS. In addition, the lack of national clinical guidelines and absence of affordable, effective treatments contribute to worse outcomes and higher mortality in LMIC than HIC. Systematic population-based surveillance studies, cohort and case-control studies are required to understand the incidence and risk factors for GBS. Novel, targeted and cost-effective treatment strategies need to be developed in the context of health system challenges in LMIC. To ensure integrative rehabilitation services in LMIC, existing prognostic models must be validated, and responsive outcome measures that are cross-culturally applicable must be developed. Therefore, fundamental and applied research to improve the clinical management of GBS in LMIC should become a critical focus of future research programmes.

Clinical trial readiness study of distal myopathy and dysphagia in nephropathic cystinosis

BACKGROUND

Nephropathic cystinosis is a lysosomal storage disorder with late-onset systemic complications, such as myopathy and dysphagia. Currently employed outcome measures lack sensitivity and responsiveness for dysphagia and myopathy, a limitation to clinical trial readiness.

METHODS

We evaluated 20 patients with nephropathic cystinosis in two visits over the course of a year to identify outcomes sensitive to detect changes over time. Patients also underwent an expiratory muscle strength training program to assess any effects on aspiration and dysphagia.

RESULTS

There were significant differences in the Timed Up and Go Test (TUG) and Timed 25-Foot Walk (25-FW) between baseline and 1-y follow-up (P < .05). Maximum expiratory pressure (MEP) and peak cough flow (PCF) significantly improved following respiratory training (P < .05).

CONCLUSIONS

Improved respiratory outcomes may enhance patients ability to expel aspirated material from the airway, stave off pulmonary sequelae associated with chronic aspiration, and yield an overall improvement in physical health and well-being.

Clinical myopathy in patients with nephropathic cystinosis

BACKGROUND

Nephropathic cystinosis is a lysosomal storage disorder. Patient survival years after renal transplantation has revealed systemic complications including distal myopathy and dysphagia.

METHODS

We evaluated 20 adult patients with nephropathic cystinosis using patient-reported and clinical outcome measures. Standard motor measures, video fluoroscopy swallow studies, and tests of respiratory function were performed. We also used Rasch analysis of an initial survey to design a 16-item survey focused on upper and lower extremity function, which was completed by 31 additional patients.

RESULTS

Distal myopathy and dysphagia were common in patients with nephropathic cystinosis. Muscle weakness ranges from mild involvement of intrinsic hand muscles to prominent distal greater than proximal weakness and contractures.

CONCLUSIONS

In addition to further characterization of underlying dysphagia and muscle weakness, we propose a new psychometrically devised, disease specific, functional outcome measures for distal myopathy in patients with nephropathic cystinosis.

Normative reference values for strength and flexibility of 1,000 children and adults

OBJECTIVE

To establish reference values for isometric strength of 12 muscle groups and flexibility of 13 joint movements in 1,000 children and adults and investigate the influence of demographic and anthropometric factors.

METHODS

A standardized reliable protocol of hand-held and fixed dynamometry for isometric strength of ankle, knee, hip, elbow, and shoulder musculature as well as goniometry for flexibility of the ankle, knee, hip, elbow, shoulder, and cervical spine was performed in an observational study investigating 1,000 healthy male and female participants aged 3-101 years. Correlation and multiple regression analyses were performed to identify factors independently associated with strength and flexibility of children, adolescents, adults, and older adults.

RESULTS

Normative reference values of 25 strength and flexibility measures were generated. Strong linear correlations between age and strength were identified in the first 2 decades of life. Muscle strength significantly decreased with age in older adults. Regression modeling identified increasing height as the most significant predictor of strength in children, higher body mass in adolescents, and male sex in adults and older adults. Joint flexibility gradually decreased with age, with little sex difference. Waist circumference was a significant predictor of variability in joint flexibility in adolescents, adults, and older adults.

CONCLUSIONS

Reference values and associated age- and sex-stratified z scores generated from this study can be used to determine the presence and extent of impairments associated with neuromuscular and other neurologic disorders, monitor disease progression over time in natural history studies, and evaluate the effect of new treatments in clinical trials.

Progress in inflammatory neuropathy -the legacy of Dr Jack Griffin

The past quarter of a century has brought incredible advances in our understanding of inflammatory neuropathies, and the insights into Guillain-Barré syndrome (GBS) began in the 1990s with the seminal work of Dr Jack Griffin and his colleagues. In this essay, we provide a tribute to Jack, and review the recent progress in a field that he termed his personal favourite. In particular, we discuss the new developments in our understanding and diagnosis of inflammatory neuropathies, the recent emergence of the node of Ranvier and the paranode as sites of intensive investigation, and the mechanistic evidence that is providing a platform for therapeutic development studies.