Validation of the Parent-Proxy Version of the Pediatric Charcot-Marie-Tooth Disease Quality of Life Instrument for children aged 0-7 years

OBJECTIVE: To evaluate the parent-proxy version of the pediatric Charcot Marie Tooth specific quality of life (pCMT-QOL) outcome instrument for children aged 7 or younger with CMT. We have previously developed and validated the direct-report pCMT-QOL for children aged 8-18 years and a parent proxy version of the instrument for children 8-18 years old. There is currently no CMT-QOL outcome measure for children aged 0-7 years old. METHODS: Testing was conducted in parents or caregivers of children aged 0-7 years old with CMT evaluated at participating INC sites from the USA, United Kingdom, and Australia. The development of the instrument was iterative, involving identification of relevant domains, item pool generation, prospective pilot testing and clinical assessments, structured focus group interviews and psychometric testing. The parent-proxy instrument was validated rigorously by examining previously identified domains and undergoing psychometric tests for children aged 0-7. RESULTS: The parent-proxy pCMT-QOL working versions were administered to 128 parents/caregivers of children aged 0-7 years old between 2010 and 2016. The resulting data underwent rigorous psychometric analysis, including factor analysis, internal consistency, and convergent validity, and longitudinal analysis to develop the final parent-proxy version of the pCMT-QOL outcome measure for children aged 0-7 years old. CONCLUSIONS: The parent-proxy version of the pCMT-QOL outcome measure, known as the pCMT-QOL (0-7 years parent-proxy) is a valid and sensitive proxy measure of health-related QOL for children aged 0-7 years with CMT. This article is protected by copyright. All rights reserved

Ambulatory function in spinal muscular atrophy: Age-related patterns of progression

Individuals with spinal muscular atrophy (SMA) type 3 are able to walk but they have weakness, gait impairments and fatigue. Our primary study objective was to examine longitudinal changes in the six-minute walk test (6MWT) and to evaluate whether age and SMA type 3 subtype are associated with decline in ambulatory function. Data from three prospective natural history studies were used. Seventy-three participants who performed the 6MWT more than once, at least 6 months apart, were included; follow-up ranged from 0.5–9 years. Only data from patients who completed the 6MWT were included. The mean age of the participants was 13.5 years (range 2.6–49.1), with 52 having disease onset before age 3 years (type 3A). At baseline, type 3A participants walked a shorter distance on average (257.1 m) than type 3B participants (390.2 m) (difference = 133.1 m, 95% confidence interval [CI] 71.8–194.3, p < 0.001). Distance walked was weakly associated with age (r = 0.25, p = 0.04). Linear mixed effects models were used to estimate the mean annual rate of change. The overall mean rate of change was -7.8 m/year (95% CI -13.6 –-2.0, p = 0.009) and this did not differ by subtype (type 3A: -8.5 m/year, type 3B: -6.6 m/year, p = 0.78), but it did differ by age group (< 6: 9.8 m/year; 6–10: -7.9 m/year; 11–19: -20.8 m/year; ≥ 20: -9.7 m/year; p = 0.005). Our results showed an overall decline on the 6MWT over time, but different trajectories were observed depending on age. Young ambulant SMA patients gain function but in adolescence, patients lose function. Future clinical trials in ambulant SMA patients should consider in their design the different trajectories of ambulatory function over time, based on age

2-Year Change in Revised Hammersmith Scale Scores in a Large Cohort of Untreated Paediatric Type 2 and 3 SMA Participants

The Revised Hammersmith Scale (RHS) is a 36-item ordinal scale developed using clinical expertise and sound psychometrics to investigate motor function in participants with Spinal Muscular Atrophy (SMA). In this study, we investigate median change in the RHS score up to two years in paediatric SMA 2 and 3 participants and contextualise it to the Hammersmith Functional Motor Scale-Expanded (HFMSE). These change scores were considered by SMA type, motor function, and baseline RHS score. We consider a new transitional group, spanning crawlers, standers, and walkers-with-assistance, and analyse that alongside non-sitters, sitters, and walkers. The transitional group exhibit the most definitive change score trend, with an average 1-year decline of 3 points. In the weakest patients, we are most able to detect positive change in the RHS in the under-5 age group, whereas in the stronger patients, we are most able to detect decline in the RHS in the 8-13 age group. The RHS has a reduced floor effect compared to the HFMSE, although we show that the RHS should be used in conjunction with the RULM for participants scoring less than 20 points on the RHS. The timed items in the RHS have high between-participant variability, so participants with the same RHS total can be differentiated by their timed test items

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 &gt;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. (C) 2021 Elsevier B.V. All rights reserved

Individual trajectories and average trajectory of 6MWT distance by age group.

<p>Individual trajectories and average trajectory of 6MWT distance by age group.</p

Mean annual rate of change in 6MWT distance and 95% confidence interval by age group.

<p>Mean annual rate of change in 6MWT distance and 95% confidence interval by age group.</p

Age group comparisons of mean annual rate of change on the 6MWT.

<p>Age group comparisons of mean annual rate of change on the 6MWT.</p

Baseline clinical characteristics for all participants by age and SMA subtype.

<p>Baseline clinical characteristics for all participants by age and SMA subtype.</p

Mean annual rate of change on the 6MWT, overall and by subgroup.

<p>Mean annual rate of change on the 6MWT, overall and by subgroup.</p

Functional outcome measures in young, steroid-naïve boys with Duchenne muscular dystrophy.

The purpose of this study was to quantitate motor performance in 196 genetically confirmed steroid-naïve boys with Duchenne muscular dystrophy (DMD), to evaluate the test-retest reliability of measures of motor performance in young DMD boys, and to assess correlations among the different functional outcomes including timed tests. Boys aged 4-7 years were recruited in the FOR-DMD study, a comparative effectiveness study of different steroid regimens in DMD. Eligible boys had to be able to rise from the floor independently and to perform pulmonary function testing consistently. The boys were evaluated with standardized assessments at the screening and baseline visits at 32 sites in 5 countries (US, UK, Canada, Italy, Germany). Assessments included timed rise from floor, timed 10 m walk/run, six-minute walk distance, North Star Ambulatory Assessment (NSAA) and forced vital capacity (FVC). Mean age at baseline was 5.9 years (range 4.1-8.1 years). Test-retest reliability was high for functional assessments, regardless of time lag between assessments (up to 90 days) and for the majority of age groups. Correlations were strong among the functional measures and timed tests, less so with FVC. Physiotherapy measures are reliable in a young, steroid-naïve population and rise from floor velocity appears to be a sensitive measure of strength in this population