Measurement properties and utility of performance-based outcome measures of physical functioning in individuals with facioscapulohumeral dystrophy - A systematic review and evidence synthesis

Muscle imaging in facioscapulohumeral muscular dystrophy research: A scoping review and expert recommendations

Clinical trial readiness is an important topic in the field of facioscapulohumeral muscular dystrophy (FSHD). As FSHD is a slowly progressive and clinically heterogeneous disease, imaging biomarkers have been proposed to complement clinical outcome measures. Muscle magnetic resonance imaging (MRI), ultrasound and dual energy X-ray absorptiometry (DEXA) have been used to measure disease severity, activity and progression. We conducted a scoping review of the literature on these imaging modalities to assess gaps in knowledge and subsequently collaborated with a panel of neuromuscular imaging experts to generate recommendations on the road ahead. We systematically searched PubMed, EMBASE and Cochrane Library databases. Three-hundred and twenty-eight studies were screened and one hundred and five studies were included. MRI indices related to intramuscular fat content, STIR positivity and T2water are used as diagnostic as well as prognostic and monitoring biomarkers. Ultrasound echogenicity can be used as a diagnostic and potentially as a prognostic and monitoring biomarker. DEXA lean muscle mass may be used as an additional monitoring biomarker. Each imaging modality has its own benefits but also challenges. Based on our expert opinions, we propose a roadmap to address these challenges, ensuring the optimal use of each modality in multi-center clinical trials in FSHD.

A 5-year natural history cohort of patients with facioscapulohumeral muscular dystrophy determining disease progression and feasibility of clinical outcome assessments for clinical trials

INTRODUCTION/AIMS

The number of clinical trials in facioscapulohumeral muscular dystrophy (FSHD) is expected to increase in the near future. There is a need for clinical outcome assessments (COAs) that can capture disease progression over the relatively short time span of a clinical trial. In this study, we report the natural progression of FSHD and determine the feasibility of COAs for clinical trials.

METHODS

Genetically confirmed FSHD patients underwent various COAs at baseline and after 5 years. COAs consisted of the Motor Function Measure (MFM), manual muscle testing using the Medical Research Council score, six-minute walk test, quantitative muscle strength assessment of the quadriceps muscle, clinical severity score, and FSHD evaluation score (FES). Statistical significance and the minimal clinically important difference (MCID) were calculated and power calculations were performed.

RESULTS

One hundred fifty-four symptomatic FSHD patients were included, with a mean (SD) age of 51.4 (14.6) years old. All COAs showed a minimal, yet statistically significant progression after 5 years. MCID was reached for the MFM Domain 1, MFM total score, and FES. These three COAs showed the lowest sample size requirements for clinical trials (185, 156, and 201 participants per group, respectively, for a trial duration of 2 years).

DISCUSSION

The captured FSHD disease progression rate in 5 years was generally minimal. The COAs in this study are not feasible for clinical trials with a duration of 2 years. Extended trial durations or novel outcome assessments might be necessary to improve trial feasibility in FSHD.

Reliability and validity of the FSHD-composite outcome measure in childhood facioscapulohumeral dystrophy

This study aims to investigate intra-rater reliability and construct validity of the Facioscapulohumeral Dystrophy Composite Outcome Measure (FSHD-COM), in childhood FSHD. Participants included eighteen children with FSHD, and matched healthy controls. Reliability data were collected from 15 participants with FSHD over two testing sessions. Validity data were collected from all participants. Participants with FSHD completed; the FSHD-COM (and modified pediatric version), Motor Function Measure-32 (MFM-32), FSHD Severity Scales, Performance of the Upper Limb 2.0, Pediatric Quality of Life™ Neuromuscular Module and pediatric FSHD Health-Index Questionnaire. Both versions of the FSHD-COM showed excellent intra-rater reliability (ICC_1,2 > 0.99, lower 95%CI > 0.98) with a Minimal Detectable Change (MDC95%) of ≤14.5%. The FSHD-COM had robust and widespread correlations with other related outcome measures. The FSHD-COM versions and 6 min walk test effectively discriminated between children with and without FSHD; the MFM-32 and 10 m walk/run test did not. Ceiling effects were not observed on either version of the FSHD-COM. Reliability and validity findings in this childhood FSHD study concord with estimates in adults. Both versions of the FSHD-COM were effective in discriminating disease in children with mild FSHD symptoms. The FSHD-COM has the potential to be a useful measure of function across the life span.