Rasch analysis of clinical outcome measures in spinal muscular atrophy.

INTRODUCTION: Trial design for SMA depends on meaningful rating scales to assess outcomes. In this study Rasch methodology was applied to 9 motor scales in spinal muscular atrophy (SMA). METHODS: Data from all 3 SMA types were provided by research groups for 9 commonly used scales. Rasch methodology assessed the ordering of response option thresholds, tests of fit, spread of item locations, residual correlations, and person separation index. RESULTS: Each scale had good reliability. However, several issues impacting scale validity were identified, including the extent that items defined clinically meaningful constructs and how well each scale measured performance across the SMA spectrum. CONCLUSIONS: The sensitivity and potential utility of each SMA scale as outcome measures for trials could be improved by establishing clear definitions of what is measured, reconsidering items that misfit and items whose response categories have reversed thresholds, and adding new items at the extremes of scale ranges.

Rasch analysis of the motor function measure in patients with congenital muscle dystrophy and congenital myopathy.

OBJECTIVES: To monitor treatment effects in patients with congenital myopathies and congenital muscular dystrophies, valid outcome measures are necessary. The Motor Function Measure (MFM) was examined for robustness, and changes are proposed for better adequacy. DESIGN: Observational study based on data previously collected from several cohorts. SETTING: Nineteen departments of physical medicine or neuromuscular consultation in France, Belgium, and the United States. PARTICIPANTS: Patients (N=289) aged 5 to 77 years. INTERVENTIONS: None. MAIN OUTCOME MEASURES: A Rasch analysis examined the robustness of the MFM across the disease spectrum. The 3 domains of the scale (standing position and transfers, axial and proximal motor function, and distal motor function) were independently examined with a partial credit model. RESULTS: The original 32-item MFM did not sufficiently fit the Rasch model expectations in either of its domains. Switching from a 4- to a 3-category response scale in 18 items restored response order in 16. Various additional checks suggested the removal of 7 items. The resulting Rasch-scaled Motor Function Measure with 25 items for congenital disorders of the muscle (Rs-MFM25(CDM)) demonstrated a good fit to the Rasch model. Domain 1 was well targeted to the whole severity spectrum-close mean locations for items and persons (0 vs 0.316)-whereas domains 2 and 3 were better targeted to severe cases. The reliability coefficients of the Rs-MFM25(CDM) suggested sufficient ability for each summed score to distinguish between patient groups (0.9, 0.8, and 0.7 for domains 1, 2, and 3, respectively). A sufficient agreement was found between results of the Rasch analysis and physical therapists' opinions. CONCLUSIONS: The Rs-MFM25(CDM) can be considered a clinically relevant linear scale in each of its 3 domains and may be soon reliably used for assessment in congenital disorders of the muscle.

English cross-cultural translation and validation of the neuromuscular score: a system for motor function classification in patients with neuromuscular diseases.

OBJECTIVE: To develop and validate an English version of the Neuromuscular (NM)-Score, a classification for patients with NM diseases in each of the 3 motor function domains: D1, standing and transfers; D2, axial and proximal motor function; and D3, distal motor function. DESIGN: Validation survey. SETTING: Patients seen at a medical research center between June and September 2013. PARTICIPANTS: Consecutive patients (N=42) aged 5 to 19 years with a confirmed or suspected diagnosis of congenital muscular dystrophy. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: An English version of the NM-Score was developed by a 9-person expert panel that assessed its content validity and semantic equivalence. Its concurrent validity was tested against criterion standards (Brooke Scale, Motor Function Measure [MFM], activity limitations for patients with upper and/or lower limb impairments [ACTIVLIM], Jebsen Test, and myometry measurements). Informant agreement between patient/caregiver (P/C)-reported and medical doctor (MD)-reported NM scores was measured by weighted kappa. RESULTS: Significant correlation coefficients were found between NM scores and criterion standards. The highest correlations were found between NM-score D1 and MFM score D1 (ρ=-.944, P<.0001), ACTIVLIM (ρ=-.895, P<.0001), and hip abduction strength by myometry (ρ=-.811, P<.0001). Informant agreement between P/C-reported and MD-reported NM scores was high for D1 (κ=.801; 95% confidence interval [CI], .701-.914) but moderate for D2 (κ=.592; 95% CI, .412-.773) and D3 (κ=.485; 95% CI, .290-.680). Correlation coefficients between the NM scores and the criterion standards did not significantly differ between P/C-reported and MD-reported NM scores. CONCLUSIONS: Patients and physicians completed the English NM-Score easily and accurately. The English version is a reliable and valid instrument that can be used in clinical practice and research to describe the functional abilities of patients with NM diseases.

Responsiveness of the motor function measure in patients with spinal muscular atrophy.

OBJECTIVE: To assess the ability of the Motor Function Measure (MFM) to detect changes in the progression of spinal muscular atrophy (SMA). DESIGN: Observational, retrospective, multicenter cohort study. SETTING: Seventeen departments of pediatric physical medicine. PARTICIPANTS: Volunteer patients with SMA (N=112) aged 5.7 to 59 years with no treatment other than physical therapy and nutritional or respiratory assistance. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The distributions of the MFM scores (total score and 3 subscores) were analyzed per SMA subtype. The relationships between scores and age were studied. The slopes of score changes (reflecting MFM responsiveness) were estimated in patients with at least 6 months' follow-up and 2 MFMs. Hypothetical sample sizes for specific effect sizes in clinical trial scenarios are given. RESULTS: In 12 patients with SMA type 2 and 19 with SMA type 3 (mean ± SD follow-up, 25.8 ± 19mo), there was a moderate inverse relationship between age and the MFM total score. Patients with less than 6 months' follow-up showed little score changes. Patients with longer follow-ups showed a slow deterioration (-0.9 points/y for type 2 and -0.6 points/y for type 3). Substantial responsiveness was obtained with the MFM Dimension 2 subscore (proximal and axial motricity) in patients with SMA type 2 (standardized response mean [SRM]=1.29), and with the MFM Dimension 1 subscore (standing and transfers) in patients with SMA type 3 aged 10 to 15 years (SRM=.94). CONCLUSIONS: If further confirmed by larger studies, these preliminary results on the relative responsiveness of the MFM in SMA will foster its use in monitoring disease progression in patients who participate in clinical trials.

Motor function measure: validation of a short form for young children with neuromuscular diseases.

OBJECTIVE: To validate a useful version of the Motor Function Measure (MFM) in children with neuromuscular diseases aged <7 years old. DESIGN: Two prospective cohort studies that documented the MFM completion of children aged between 2 and 7 years old. SETTING: French-speaking rehabilitation departments from France, Belgium, and Switzerland. PARTICIPANTS: Healthy children (n=194) and children with a neuromuscular disease (n=88). INTERVENTIONS: Patients were rated by the MFM either once or twice by trained medical professionals, with a delay between the 2 MFMs ranging between 8 and 30 days. MAIN OUTCOME MEASURE: Intra- and interrater reliability of the MFM. RESULTS: The subtests making up the MFM-32, a scale monitoring severity and progression of motor function in patients with a neuromuscular disease in 3 functional domains, were carried out in healthy children aged 2 to 7 years. Twenty items of the MFM-32 were successfully completed by these children and were used to constitute the MFM-20. Principal component analysis of the MFM-20 confirmed the 3 functional domains. Inter- and intrarater reliability of the 3 subscores and total score were high (intraclass correlation coefficient >.90), and discriminant validity was good. CONCLUSIONS: The MFM-20 can be used as an outcome measure for assessment of motor function in young children with neuromuscular disease.

Responsiveness of the motor function measure in neuromuscular diseases.

OBJECTIVES: To study the responsiveness (sensitivity to change) of the Motor Function Measure (MFM) in detecting change in neuromuscular disease patients with the intent of using this measure in future clinical trials. DESIGN: Prospective cohort observational study. SETTING: Inpatient and outpatient facilities for follow-up and treatment of neuromuscular diseases. PARTICIPANTS: Patients (N=152) with various neuromuscular diseases aged 6 to 60 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S): We used the MFM total score and its 3 subscores on 2 measurements grossly 1 year apart. The physicians and the patients (or proxy) were asked to provide their perceived change in functional status since the first MFM. These changes were expressed in 3 outcomes: deterioration, stability, or improvement. RESULTS: The overall 12-month-standardized mean change of the total score mean ± SD annual total score change was -2.4±5.5 points (P<.001), with patients with Duchenne muscular dystrophy (DMD) presenting the most significant change (-5.8±6.3, P<.001). The change in patients reporting deterioration (34%) was significantly larger than that of those reporting stability (47%) or improvement (10%) (-4.4±6.4 vs -2.0±5.6 and +0.9±4.4 points, respectively, P<.01). The 12-month-standardized total score changes were significantly greater in physician-rated deteriorated (49%) versus stable patients (51%), with mean differences in scores being -5.3±7.6 and -1.2±5.3, respectively (P<.001). CONCLUSIONS: The MFM showed a good responsiveness, especially in patients with DMD and agreements with patients' and physicians' perceived change. Confirming this responsiveness requires larger age groups of patients with DMD and other neuromuscular diseases as well as disease-specific interexamination delays.

Impact of Airway Humidification Strategy in Mechanically Ventilated COVID-19 Patients.

BACKGROUND: Humidification of inspiratory gases is mandatory in all mechanically ventilated patients in ICUs, either with heated humidifiers (HHs) or with heat and moisture exchangers (HMEs). In patients with COVID-19, the choice of the humidification device may have relevant impact on patients' management as demonstrated in recent studies. We reported data from 2 ICUs using either HME or HH. METHODS: Data from patients with COVID-19 requiring invasive mechanical ventilation during the first wave in 2 ICUs in Québec City were reviewed. In one ICU, HMEs were used, whereas heated-wire HHs were used in the other ICU. We compared ventilator settings and arterial blood gases at day one after adjustment of ventilator settings. Episodes of endotracheal tube occlusions (ETOs) or subocclusions and a strategy to limit the risk of under-humidification were reported. On a bench test, we measured humidity with psychrometry with HH at different ambient temperature and evaluated the relation with heater plate temperature. RESULTS: We reported data from 20 subjects positive for SARS-Cov-2, including 6 in the ICU using HME and 14 in the ICU using HH. In the HME group, PaCO2 was higher (48 vs 42 mm Hg) despite higher minute ventilation (171 vs 145 mL/kg/min predicted body weight [PBW]). We also reported 3 ETOs occurring in the ICU using HH. The hygrometric bench study reported a strong correlation between heater plate temperatures of the HH and humidity delivered. After implementation of measures to avoid under-humidification, including heater plate temperature monitoring, no more ETOs occurred. CONCLUSIONS: The choice of the humidification device used in subjects with COVID-19 had a relevant impact on ventilation efficiency (increased CO2 removal with lower dead space) and on complications related to low humidity, including ETOs that may be present with heated-wire HHs when used with high ambient temperatures.

Monitoring changes and predicting loss of ambulation in Duchenne muscular dystrophy with the Motor Function Measure.

AIM: To assess changes in motor function in patients with Duchenne muscular dystrophy using the Motor Function Measure (MFM). METHOD: Three studies were performed. Two studies included only physiotherapy-treated patients, with 13 patients (males mean age 11y 7mo, SD 1y 10mo, range 8-14y) in the 3-month study and 41 patients (males mean age 14y 1mo, SD 5y 5mo, range 6-32y) in the 1-year study. A third study compared 12 patients treated with steroids with 12 age- and motor-function-matched untreated patients (males mean age of treated patients 10y 2mo, SD 2y 2mo range 6-14) over a 12-month period. RESULTS: Over 3 months, the MFM D1 subscore (standing and transfers) decreased significantly (-4.7%; p<0.01). Over 1 year, all MFM subscores decreased significantly: -4.9% for D1 (p<0.01); -7.7% for D2 (axial and proximal motor capacity; p<0.01); -4.3% for D3 (distal motor capacity; p=0.03); and -5.8% for the total score (p<0.01). A threshold value for loss of ambulation and a predictive value 1 year before loss were estimated (total score 70% and D1 subscore 40%). Compared with the controls, patients treated with steroids had more stable total scores (-0.59 vs -5.87; p=0.02) and D2 subscores (0.98 vs -8.50; p<0.01). INTERPRETATION: These results support the use of the MFM in everyday patient management to prepare for loss of ambulation and in clinical trials to follow up patients receiving various treatments.

A 7-year longitudinal follow-up of intellectual development in children with congenital hemiplegia.

AIMS: Our aim was to examine intellectual development in children with congenital hemiplegia from early childhood to adolescence. METHOD: Full-scale IQ (FIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) scores were measured in 32 participants (19 males, 13 females) with congenital hemiplegia at mean ages of 4 years 6 months (SD 7mo; 31 participants), 7 years (SD 6mo; 23 participants), and 14 years (SD 1y 5mo; 26 participants). RESULTS: The FIQ and VIQ scores did not change with age, but the PIQ declined significantly (0.7 points per year; p=0.004). The estimated mean (95% confidence intervals) scores in males born at term with right-sided lesions without epilepsy were FIQ 106.5 (95.29-117.74), VIQ 105.9 (95.57-116.24), and PIQ 103.7 (93.19-114.31). Those means were negatively associated with preterm birth. PIQ was negatively associated with epilepsy. VIQ increased more quickly in males and in children with right-sided lesions. INTERPRETATION: The results confirm previous findings of FIQ stability, PIQ decline, the impact of epilepsy, and the status of females with left-sided lesions, and also reveal the effect of gestational age at birth. They underline the importance of management focused on nonverbal functions and further the debate about the early lateralization of language, the 'crowding effect', and the difference in brain plasticity between males and females.

Development of a decision aid for cardiopulmonary resuscitation and invasive mechanical ventilation in the intensive care unit employing user-centered design and a wiki platform for rapid prototyping.

BACKGROUND: Upon admission to an intensive care unit (ICU), all patients should discuss their goals of care and express their wishes concerning life-sustaining interventions (e.g., cardiopulmonary resuscitation (CPR)). Without such discussions, interventions that prolong life at the cost of decreasing its quality may be used without appropriate guidance from patients. OBJECTIVES: To adapt an existing decision aid about CPR to create a wiki-based decision aid individually adapted to each patient's risk factors; and to document the use of a wiki platform for this purpose. METHODS: We conducted three weeks of ethnographic observation in our ICU to observe intensivists and patients discussing goals of care and to identify their needs regarding decision making. We interviewed intensivists individually. Then we conducted three rounds of rapid prototyping involving 15 patients and 11 health professionals. We recorded and analyzed all discussions, interviews and comments, and collected sociodemographic data. Using a wiki, a website that allows multiple users to contribute or edit content, we adapted the decision aid accordingly and added the Good Outcome Following Attempted Resuscitation (GO-FAR) prediction rule calculator. RESULTS: We added discussion of invasive mechanical ventilation. The final decision aid comprises values clarification, risks and benefits of CPR and invasive mechanical ventilation, statistics about CPR, and a synthesis section. We added the GO-FAR prediction calculator as an online adjunct to the decision aid. Although three rounds of rapid prototyping simplified the information in the decision aid, 60% (n = 3/5) of the patients involved in the last cycle still did not understand its purpose. CONCLUSIONS: Wikis and user-centered design can be used to adapt decision aids to users' needs and local contexts. Our wiki platform allows other centers to adapt our tools, reducing duplication and accelerating scale-up. Physicians need training in shared decision making skills about goals of care and in using the decision aid. A video version of the decision aid could clarify its purpose.

Perindopril preventive treatment on mortality in Duchenne muscular dystrophy: 10 years' follow-up.

BACKGROUND: Duchenne muscular dystrophy (DMD), an X-linked disorder due to lack of dystrophin, is associated with muscle weakness and myocardial dysfunction. Although preliminary data support the efficacy of angiotensin-converting enzyme inhibitors on left ventricular (LV) function, our aim was to examine the long-term impact of a preventive treatment with perindopril on mortality in children with DMD. METHODS: Patients with DMD between the ages of 9.5 and 13 years presenting with normal LV ejection fraction were included in this prospective study. They were randomly assigned for 3 years to perindopril, 2 to 4 mg (group 1), or placebo (group 2) in a double-blind protocol, followed by open-label treatment with perindopril for up to 10 years. Survival rate at 10 years in each group is reported. RESULTS: There were 28 patients assigned to group 1 and 29 to group 2. Baseline characteristics were similar in both groups. At the end of the 10 years' follow-up period, survival status was available for all included patients: 26 (92.9%) of 28 patients in group 1 were alive at 10 years versus 19 (65.5%) of 29 in group 2 (P = .02). Kaplan-Meier cumulative survival was significantly lower in group 2 than in group 1 (P = .013). CONCLUSION: Early initiation of treatment with perindopril is associated with a lower mortality in patients with DMD with normal LV ejection fraction at study entry.

Use and tolerability of a side pole static ankle foot orthosis in children with neurological disorders.

BACKGROUND: Transverse-plane foot deformities are a frequently encountered issue in children with neurological disorders. They are the source of many symptoms, such as pain and walking difficulties, making their prevention very important. OBJECTIVES: We aim to describe the use and tolerability of a side pole static ankle foot orthosis used to prevent transverse-plane foot deformities in children with neurologic disorders. STUDY DESIGN: Monocentric, retrospective, observational study. METHODS: Medical data were collected from 103 children with transverse-plane foot deformities in one or both feet caused by a neurological impairment. All children were braced between 2001 and 2010. RESULTS: Unilateral orthosis was prescribed for 32 children and bilateral orthosis for 71. Transverse-plane foot deformities were varus in 66% of the cases and an equinus was associated in 59.2% of the cases. Mean age for the first prescription was 8.6 years. For the 23 patients present at the 4-year visit, 84.8% still wore the orthosis daily, and 64.7% wore the orthosis more than 6 h per day. The rate of permanent discontinuation of wearing the orthosis was 14.7%. CONCLUSION: The side pole static ankle foot orthosis is well tolerated with very few side effects, which promotes regular wearing and observance. Clinical relevance Side pole static ankle foot orthoses are well tolerated and can be safely used for children with foot abnormalities in the frontal plane that have a neurological pathology origin.

Brain MRI abnormalities in muscular dystrophy due to FKRP mutations.

INTRODUCTION: FKRP mutations cause a muscular dystrophy which may present in the neonatal period (MDC1C) or later in life (LGMD2I). Intelligence and brain imaging have been previously reported as being normal in FKRP-associated muscular dystrophy, except in rare cases presenting with mental retardation associated with structural brain abnormalities. PATIENTS AND METHODS: We studied cerebral MRIs in twelve patients with FKRP-associated muscular dystrophy presenting in infancy or early childhood, at ages between 14 months and 43 years. Two patients had severe cognitive deficits, four had mild-moderate mental retardation and the rest were considered to have normal intelligence. All, but one were wheelchair-bound and 7 were mechanically ventilated. RESULTS: Brain MRI was abnormal in 9 of 12 patients. Brain atrophy was seen in 8 patients. One child had isolated ventricular enlargement at 4 years. Cortical atrophy involved predominantly temporal and frontal lobes and was most important at later ages. In two cases with serial images this atrophy seemed progressive. Three patients, two with severe and one with moderate mental retardation, showed structural abnormalities of the posterior fossa with hypoplasia of the vermis and pons, and cerebellar hemispheric cysts. These abnormalities were stable with time. Two of these three patients also showed diffuse white matter abnormalities in early childhood, which regressed with time. CONCLUSIONS: MRI abnormalities are common in patients with FKRP-associated muscular dystrophy presenting at birth or in early childhood. Progressive brain atrophy is the most frequent finding. Posterior fossa malformations and transient white matter changes may be seen in patients with associated mental retardation.

Development of a Decision Aid for Cardiopulmonary Resuscitation Involving Intensive Care Unit Patients' and Health Professionals' Participation Using User-Centered Design and a Wiki Platform for Rapid Prototyping: A Research Protocol.

BACKGROUND: Cardiopulmonary resuscitation (CPR) is an intervention used in cases of cardiac arrest to revive patients whose heart has stopped. Because cardiac arrest can have potentially devastating outcomes such as severe neurological deficits even if CPR is performed, patients must be involved in determining in advance if they want CPR in the case of an unexpected arrest. Shared decision making (SDM) facilitates discussions about goals of care regarding CPR in intensive care units (ICUs). Patient decision aids (DAs) are proven to support the implementation of SDM. Many patient DAs about CPR exist, but they are not universally implemented in ICUs in part due to lack of context and cultural adaptation. Adaptation to local context is an important phase of implementing any type of knowledge tool such as patient DAs. User-centered design supported by a wiki platform to perform rapid prototyping has previously been successful in creating knowledge tools adapted to the needs of patients and health professionals (eg, asthma action plans). This project aims to explore how user-centered design and a wiki platform can support the adaptation of an existing DA for CPR to the local context. OBJECTIVE: The primary objective is to use an existing DA about CPR to create a wiki-based DA that is adapted to the context of a single ICU and tailorable to individual patient's risk factors while employing user-centered design. The secondary objective is to document the use of a wiki platform for the adaptation of patient DAs. METHODS: This study will be conducted in a mixed surgical and medical ICU at Hôtel-Dieu de Lévis, Quebec, Canada. We plan to involve all 5 intensivists and recruit at least 20 alert and oriented patients admitted to the ICU and their family members if available. In the first phase of this study, we will observe 3 weeks of daily interactions between patients, families, intensivists, and other allied health professionals. We will specifically observe 5 dyads of attending intensivists and alert and oriented patients discussing goals of care concerning CPR to understand how a patient DA could support this decision. We will also conduct individual interviews with the 5 intensivists to identify their needs concerning the implementation of a DA. In the second phase of the study, we will build a first prototype based on the needs identified in Phase I. We will start by translating an existing DA entitled "Cardiopulmonary resuscitation: a decision aid for patients and their families." We will then adapt this tool to the needs we identified in Phase I and archive this first prototype in a wiki. Building on the wiki's programming architecture, we intend to integrate the Good Outcome Following Attempted Resuscitation risk calculator into our DA to determine personal risks and benefits of CPR for each patient. We will then present the first prototype to 5 new patient-intensivist dyads. Feedback about content and visual presentation will be collected from the intensivists through short interviews while longer interviews will be conducted with patients and their family members to inform the visual design and content of the next prototype. After each rapid prototyping cycle, 2 researchers will perform qualitative content analysis of data collected through interviews and direct observations. We will attempt to solve all content and visual design issues identified before moving to the next round of prototyping. In all, we will conduct 3 prototyping cycles with a total of 15 patient-intensivist dyads. RESULTS: We expect to develop a multimedia wiki-based DA to support goals of care discussions about CPR adapted to the local needs of patients, their family members, and intensivists and tailorable to individual patient risk factors. The final version of the DA as well as the development process will be housed in an open-access wiki and free to be adapted and used in other contexts. CONCLUSIONS: This study will shed new light on the development of DAs adapted to local context and tailorable to individual patient risk factors employing user-centered design and a wiki to support rapid prototyping of content and visual design issues.

A motor function measure for neuromuscular diseases. Construction and validation study.

A new scale for motor function measurement has been developed for neuromuscular diseases. The validation study included 303 patients, aged 6-62 years. Seventy-two patients had Duchenne muscular dystrophy, 32 Becker muscular dystrophy, 30 limb-girdle muscular dystrophy, 39 facio-scapulo-humeral dystrophy, 29 myotonic dystrophy, 21 congenital myopathy, 10 congenital muscular dystrophy, 35 spinal muscular atrophy and 35 hereditary neuropathy. The scale comprised 32 items, in three dimensions: standing position and transfers, axial and proximal motor function, distal motor function. Agreement coefficients for inter-rater reliability were excellent (kappa=0.81-0.94) for nine items, good (kappa=0.61-0.80) for 20 items and moderate (kappa=0.51-0.60) for three items. High correlations were found between the total score and other scores: Vignos (r=0.91) and Brooke (r=0.85) grades, Functional Independence Measure (r=0.91), the global severity of disability evaluated with visual analog scales by physicians (r=0.88) and physiotherapists (r=0.91). This scale is reliable, does not require any special equipment and is well-accepted by patients. Its sensitivity to change is being assessed to permit its use in clinical trials of neuromuscular diseases.

[Spinal muscular atrophy. A 4-year prospective, multicenter, longitudinal study (168 cases)]. / Amyotrophie spinale infantile. Etude multicentrique prospective et longitudinale de 168 cas suivis 4 ans.

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterised by motoneuron degeneration in the anterior horn of the spinal cord and in the bulbar nuclei. The various types of SMA are linked to the 5q13 locus in 95 % of cases. In the absence of an effective specific treatment, orthopaedic and respiratory management can significantly improve the prognosis. To study the contemporary natural history of SMA and to identify clinical and non invasive prognostic criteria, 168 patients with SMA were recruited in 6 hospital units (Lille, Lyon, Marseille, Paris) during a 4-year prospective multicenter follow-up study (1998-2002). Follow-up has now lasted at least 4 years in 151 cases (90%), and 24 of these patients have died Disease outcome was appraised by using three criteria: muscle strength, the sum of the motor function and examination index (IFM), the respiratory muscle paralysis index (IMR), and the dorsal decubitus forced vital capacity/theoretical index (ICV/CT). Statistical analysis showed a significant worsening (about 20%) of the three criteria during follow-up. The motor function and examination index (IFM) is particularly interesting: the difference between initial and final status was significant in all age groups and in all three types of the disease. The IFM may thus be useful as the main outcome measure during therapeutic trials.

Influence of a two-year steroid treatment on body composition as measured by dual X-ray absorptiometry in boys with Duchenne muscular dystrophy.

Steroids are nowadays routinely used as a long-term treatment in Duchenne muscular dystrophy (DMD). Their effects on body composition were assessed using dual X-ray absorptiometry. The study followed over 2 years 29 genetically confirmed DMD patients: 21 in the steroid-treated group and 8 in the steroid-naïve group. After 2 years of steroid treatment, the lean tissue mass values increased significantly (p<0.0001), the percentage of body fat mass remained practically constant (p=0.94) in comparison with the initial visit. In the steroid-naïve patients, there were no significant increases in the lean tissue mass but deterioration in body composition confirmed by a significant increase in the percentage of body fat mass. Besides, significant negative correlations were found between the percentage of body fat mass and the MFM total score (R=-0.79, n=76, p<0.0001). A 2-year steroid treatment improves significantly body composition of boys with DMD through a significant increase in lean tissue mass. We suggest that a thorough check of body composition should be carried out before steroid treatment discontinuation in case of overweight gain.

Motor and respiratory heterogeneity in Duchenne patients: implication for clinical trials.

AIMS: Our objective was to clarify the clinical heterogeneity in Duchenne muscular dystrophy (DMD). METHODS: The French dystrophinopathy database provided clinical, histochemical and molecular data of 278 DMD patients (mean longitudinal follow-up: 14.2 years). Diagnosis was based on mutation identification in the DMD gene. Three groups were defined according to the age at ambulation loss: before 8 years (group A); between 8 and 11 years (group B); between 11 and 16 years (group C). RESULTS: Motor and respiratory declines were statistically different between the three groups, as opposed to heart involvement. When acquired, running ability was lost at the mean age of 5.41 (group A), 7.11 (group B), 9.19 (group C) years; climbing stairs ability at 6.24 (group A), 7.99 (group B), 10,42 (group C) years, and ambulation at 7.10 (group A), 9.25 (group B), 12.01 (group C) years. Pulmonary growth stopped at 10.26 (group A), 12.45 (group B), 14.58 (group C) years. Then, forced vital capacity decreased at the rate of 8.83 (group A), 7.52 (group B), 6.03 (group C) percent per year. Phenotypic variability did not rely on specific mutational spectrum. CONCLUSION: Beside the most common form of DMD (group B), we provide detailed description on two extreme clinical subgroups: a severe one (group A) characterized by early severe motor and respiratory decline and a milder subgroup (group C). Compared to group B or C, four to six times fewer patients from group A are needed to detect the same decrease in disease progression in a clinical trial.