DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY
ORIGINAL ARTICLE
Monitoring changes and predicting loss of ambulation in Duchenne
muscular dystrophy with the Motor Function Measure
CAROLE VUILLEROT
PHD
4
|
JEAN IWAZ
MD
PHD
1,2
| FRANOISE GIRARDOT PT 1 , 2 | CHRISTINE PAYAN MD 3 |
| CAPUCINE DE LATTRE MD 1 , 2 | CAROLE BERARD MD 1 , 2
JACQUES FERMANIAN
5,6,7,8
1 Hospices Civils de Lyon, Department of Pediatric Rehabilitation, Lyon, France. 2 INSERM, Lyon, France. 3 Assistance Publique-Hpitaux de Paris, Hpital Piti-Salptrire,
Institute of Myology, Paris, France. 4 Assistance Publique-Hpitaux de Paris, Hpital Necker, Paris, France. 5 Hospices Civils de Lyon, Service de Biostatistique, Lyon, France.
6 Universit de Lyon, Lyon, France. 7 Universit Lyon I, Villeurbanne, France. 8 CNRS; UMR 5558, Laboratoire de Biomtrie et Biologie Evolutive, Equipe Biostatistique Sant,
Pierre-Bnite, France.
Correspondence to Dr Carole Vuillerot at L'Escale, Service central de rducation, Hpital Femme Mre Enfant, F-69677 Bron, France. E-mail: [email protected]
PUBLICATION DATA
AIM To assess changes in motor function in patients with Duchenne muscular dystrophy using
Accepted for publication 23rd January 2009.
Published online 22nd April 2009.
METHOD Three studies were performed. Two studies included only physiotherapy-treated
LIST OF ABBREVIATIONS
D1
Dimension 1 of the MFM (standing
and transfers)
D2
Dimension 2 of the MFM (axial and
proximal motor capacity)
D3
Dimension 3 of the MFM (distal motor
capacity)
DMD Duchenne muscular dystrophy
MFM Motor Function Measure
the Motor Function Measure (MFM).
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.
Duchenne muscular dystrophy (DMD) is one of the most frequent neuromuscular pathologies seen in paediatric rehabilitation.1 The early stages of motor decline in DMD are already
well known, including the loss of ability to walk that occurs on
average around the age of 9 years.2 However, after that age
the changes in motor capacity in children and adolescents with
DMD have been insufficiently investigated. This is especially
true for upper-limb function. Monitoring motor changes in
patients with DMD requires functional evaluation along with
measurement of muscle strength.3
The Motor Function Measure (MFM) is a tool designed
recently for neuromuscular diseases and is applicable to all
degrees of disease severity in ambulant and non-ambulant
patients. It was validated in terms of reproducibility, construct
validity, and concurrent validity.4 Its sensitivity to change has
also been assessed at a 1-year interval in 152 patients with various neuromuscular disorders. There was a good correlation
between MFM score changes and self-rated or investigatorrated disability changes.5 The need for a reliable outcome
60 DOI: 10.1111/j.1469-8749.2009.03316.x
measure in diseases of rapid deterioration such as DMD led us
to analyse the efficiency and the sensitivity to change of the
MFM, especially during the loss of ability to walk. We
attempted to answer the following three questions: (1) Is the
sensitivity of the MFM scale sufficient to detect changes in
motor function in patients receiving no other treatment than
physiotherapy over a short period of 3 months or a medium
period of 1 year? (2) Is it possible to detect differences over
only 1 year between a group of patients treated with steroids
and an untreated control group? (3) Is the MFM able to predict loss of ambulation 1 year before its occurrence in order to
allow time to adapt rehabilitation, change the patient’s environment, and consider acquisition of assistive aids?
METHOD
Participants
Patients were enrolled in 17 rehabilitation or neuromuscular
centres: 16 French and one Swiss. The single inclusion condition was a diagnosis of DMD confirmed by genetic analysis or
ª The Authors. Journal compilation ª Mac Keith Press 2009
muscle biopsy showing lack of dystrophin. Patients with
DMD with recent trauma or intercurrent disease affecting
their motor function and patients with severe mental or
behavioural difficulties were excluded.
Each patient was examined twice, at baseline and at end of
follow-up. At each examination, a trained physiotherapist
administered the MFM scale and rated the cooperation of the
participant as poor, good, or excellent. The ability to walk
(ambulation) was also assessed. This was defined as the ability
(yes ⁄ no) of a participant, starting from the upright position, to
move 10 steps forward without help and without a time limit
(a ‘step’ was counted when each foot moved forward touched
the floor). The date of loss of ambulation was reported by the
family and confirmed by a physician or a physiotherapist.
The motor function measure
The MFM is used by physiotherapists or physicians to assess
motor capacity in patients with various neuromuscular diseases. The scale assesses the motor function of patients whatever the reason for the impairment (pain, joint limitation, or
decreased strength). It was validated in 2004 in 303 patients
aged 6 to 60 years, of whom 72 had DMD.5
The MFM consists of 32 items (tasks) classified into the following three dimensions: D1, standing and transfers; D2, axial
and proximal motor capacity; and D3, distal motor capacity.
Each item is scored on a four-point Likert scale. The generic
grading is measured as follows: 0, cannot initiate the task or
cannot maintain the starting position; 1, partially performs the
task; 2, performs the task with compensatory movements
(position maintained for an insufficient period of time, slowness, uncontrolled movements, etc.); and 3, performs the task
fully and ‘normally’, the movement being controlled, mastered, directed, and performed at a constant speed.
The method of scoring each item is detailed in the User’s
Manual,6 available in English, French, and Spanish (downloadable from http://www.mfm-nmd.org). The 32 scores are
summed to yield a total score expressed as a percentage of the
maximum possible score (no physical impairment): the lower
the score, the more severe the impairment. In addition, the
three subscores (D1, D2, and D3) provide a more detailed
profile of the physical impairment.
All tests were administered by physiotherapists trained in
the MFM. It took an average of 36 minutes to perform the
whole MFM.
The studies
Three studies were performed. The first two involved 49
patients with confirmed DMD who were receiving no treatment other than physiotherapy. Five patients participated in
both studies (Fig. S1, supporting information, published
online).
The short-term study was carried out between November
2004 and March 2005. It included 13 patients examined twice,
at 3-month intervals by design. The mean interval between
the two MFMs was 3 months 11 days (SD 14d). At the first
MFM, the mean age was 11 years 7 months (range 8–14y) and
four among these patients were still ambulant.
The medium-term study was carried out between May
2002 and July 2004. It included 41 patients examined twice, at
1-year intervals by design. The mean interval was 16 months 2
days (SD 2mo 19d). At the first MFM, the mean age of the
patients was 14 years 1 month (range 6–32y) and 11 patients
were ambulant.
The third study was carried out between April 2005 and
March 2007. It compared 12 patients using steroids (of whom
four were previously enrolled in the above medium-term
study) with 12 untreated age- and motor-function-matched
patients with DMD. At first MFM, the mean age of the 12
treated patients was 10 years 2 months (range 6–14y), of whom
six were ambulant. Among the untreated patients, five were
ambulant.
The three studies were approved by the Comité Consultatif
de Protection des Personnes dans la Recherche Biomédicale
Lyon A (France) and the ethics committee of Lausanne University (Switzerland). The participants or their legal representatives signed a consent form and an information sheet on the
study protocol.
Statistical analysis
Only complete data sheets were used in the analysis (no missing
data). The means and interquartile ranges of MFM scores (D1,
D2, D3, and total score) were calculated and displayed graphically using box plots. Ages were reported as means and ranges.
In each patient, the change in a given MFM score was the difference between end of follow-up and baseline scores. The
mean score change (with SD) was then calculated within each
dimension. In the medium-term study, because of the different
follow-up periods (11–22mo), individual scores were transformed by linear interpolation into annual (12mo) score
changes. The mean change within each group (13 or 41
patients) was tested (vs zero) using the non-parametric Wilcoxon two-tailed test and comparisons of changes between groups
were made using the Mann–Whitney U two-tailed test. In all
comparisons, the significance level was set at 0.05 (two-tailed).
The sensitivity to change of the MFM scores between baseline and end of follow-up was assessed using the standard
response mean, defined as the mean score change divided by
the SD of that score change.7
Effect sizes were used to compare the subscores and total
score of patients treated with steroids to those of untreated
controls. The effect size was defined as the mean change in
score among treated patients minus the mean change among
untreated patients divided by the SD of the changes in the
untreated group.
The standard response mean and the effect size can be easily
interpreted using Cohen’s rule of thumb, which ranks the sensitivity to change into small (0.2–0.49), medium (0.50–0.79),
and large (‡0.80).8 Data were analysed with Statview software
5.0 Adept Scientific Inc., Acton, MA, USA.
RESULTS
Mean score change in short-term and medium-term studies
The cooperation of the patients was rated ‘excellent’ in all
cases except one, who was rated ‘good’ in the 3-month study.
Use of Motor Function Measure in Duchenne Muscular Dystrophy Carole Vuillerot et al. 61
100.00
90.00
Ambulant patients
Non-ambulant patients
MFM total score
80.00
70.00
60.00
50.00
40.00
30.00
y = 150.43e–0.0020
R 2 = 0.7379
20.00
10.00
0.00
0
5
10
15
20
Age (years)
y = 211.13e–0.352
R 2 = 0.7319
25
30
35
y = 460.33e–0.22323
R 2 = 0.5879
Figure 1: The curve fitting the Motor Function Measure (MFM) total scores at inclusion of the 49 untreated patients according to age. The horizontal line represents the total score of 58 that would separate ambulant from non-ambulant patients.
The total MFM scores at baseline of all 49 participants
according to age are presented in Figure 1. The curve that fits
the data shows an exponential decrease in the total score with
age (equation: total MFM score = 211.13 exp[)0.136 age]). A
total score of 58% would separate ambulant from non-ambulant patients whatever their age.
In the short-term study, the only significant mean score
change between baseline and end of follow-up was that of D1
()4.7%; p<0.01; Table I). In the medium-term study, all subscores (D1, D2, and D3) and the total score showed significant
mean score changes between baseline and end of follow-up.
These changes were )4.9% for D1 (p<0.01), )7.7% for D2
(p<0.01), )4.3% for D3 (p=0.03), and )5.8% for the total score
(p<0.01).
In the medium-term study, in the 11 patients able to walk at
baseline, the mean score change was )17.2% for D1 (SD 14.1;
range )34.2 to 13.9%) and )7.9% for the total score (SD 6.0;
range )14.6 to 6.8%). In the 30 patients unable to walk at
Table I: D1, D2, D3 values and total score of the motor function measure
completed at baseline, and score changes between baseline and end of
follow-up at 3-month and at 1-year design intervals
Scores at
baseline
Mean score
changes
D1 (standing and transfers)
3mo (n=13)
11 (15.1)
)4.7 (12.7)
12mo (n=41)
13 (21.2)
)4.9 (10.4)
D2 (axial and proximal motor capacities)
3mo (n=13)
70.1 (20.5)
)4.5 (13.9)
12mo (n=41)
58.2 (32.4)
)7.7 (11.2)
D3 (distal motor capacity)
3mo (n=13)
80.9 (13.3)
0.37 (5.3)
12mo (n=41)
74.2 (22)
)4.3 (13.7)
Total score
3mo (n=13)
48.4 (14.3)
)3.5 (10.5)
12mo (n=41)
43.3 (22.3)
)5.8 (6.3)
pa
Standard
response
mean
<0.01
<0.01
0.37
0.47
0.36
<0.01
0.32
0.68
0.63
0.03
0.07
0.3
0.46
<0.01
0.34
0.86
Values are mean (SD). aTwo-tailed Wilcoxon test.
62 Developmental Medicine & Child Neurology 2010, 52: 60–65
baseline, the mean score change was )9.4% for D2 (SD 12.5;
range )48.9 to 11.7%) and )5.0% for the total score (SD 6.3;
range )19.3 to 5.3%). Concerning the 16 patients aged over
14 at baseline, the mean score change was )3.9% for D2 (SD
8.1; range )16.6 to 11.7%), )10.8% for D3 (SD 18.5; range
)66.1 to 19%), and )3.9% for the total score (SD 6.4; range
)19.3 to 5.2%).
The individual changes in scores according to age and
walking ability showed that D1 could be of interest before loss
of ambulation because D2 and D3 remained stable before that
loss. Indeed, D2 (Fig. 2) declined at about the time of loss of
ambulation (by 10y of age) and D3 (Fig. S2, supporting
information, published online) at later stages (after 15y of
age).
Patients treated with steroids versus untreated patients
Significant differences in the mean score change were found in
the total score ()0.6% vs )5.9%, p=0.02) and in subscore D2
(1.0% vs )8.5%; p<0.01) between patients treated with steroids and untreated patients. Furthermore, MFM scores were
relatively stable in the patients treated with steroids (Table II).
MFM sensitivity to change
The standard response means in the short- and medium-term
studies are given in Table I. In the short-term study, the values
of the standard response means of all scores were medium
(all <0.49): the MFM is unable to detect only slight changes
at 3-month intervals. However, at 12 months, the standard
response mean of the total score was large (0.86), whereas that
of D2 was medium (0.68).
The effect sizes (Table II) were large (>1) for the total score
and D2 but small for D1 and D3.
Thus, the MFM can be considered sufficiently sensitive to
detect changes in the total score over a 1-year span.
Loss of ability to walk
Thirty-four out of the 49 patients (in the short- and mediumterm studies) lost their ability to walk at a mean age of 9 years
100.00
90.00
MFM D2 subscore
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0
5
10
15
20
Age (years)
25
30
35
Figure 2: Changes in Motor Function Measure (MFM) subscore D2 (axial and proximal motor capacity) at 1-year design interval according to age in the 41
patients in the long-term study.
Table II: D1, D2, D3 values and total score completed at baseline and score change over a 12-month period in 12 patients treated with steroids versus 12
untreated Duchenne muscular dystrophy (DMD) patients
D1 (standing and transfers)
Steroid-treated DMD patients
Untreated DMD patients
D2 (axial and proximal motor capacities)
Steroid-treated DMD patients
Untreated DMD patients
D3 (Distal motor capacity)
Steroid-treated DMD patients
Untreated DMD patients
Total score
Steroid-treated DMD patients
Untreated DMD patients
Scores at
baseline
Mean score
changes
Effect
size
25.0 (29.0)
18.0 (22.8)
)3.6 (8.1)
)7 (11.1)
0.31
0.71
76.3 (17.8)
75.2 (18.4)
1.0 (5.3)
)8.5 (7.8)
1.22
<0.01
81.7 (11.8)
81.0 (8.9)
2.4 (4.8)
0.7 (9)
0.19
0.27
56.7 (19.1)
53.2 (15.8)
)0.6 (4.6)
)5.9 (5.1)
1.04
0.02
pa
Values are mean (SD). aTwo-tailed Mann–Whitney U test, steroid-treated versus untreated.
5 months (range 6–14y). In the medium-term study, six out of
11 patients ambulant at baseline lost their ability to walk
between 7 and 12 years of age. Using a linear interpolation
from the observed MFM scores of these six patients, we estimated the hypothetical scores at the time of loss of ambulation
to be 63.6% (range 54.7–70.8%) for the total score and 25.0%
(range 16.7–33.3%) for D1. The MFM value that would predict loss of ambulation 1 year before it occurs can be estimated
using the mean score change at 12 months in the 11 ambulant
patients. That value can be rounded to 40% for D1 (25%
hypothetical score + 17.2%, the 1y mean change) and to 70%
for the total score (63.6% hypothetical score + 7.9%, the 1y
mean change).
The individual scores declined according to age over a 1year period in the 41 medium-term study patients shown in
Figure 2. One particular case was worth noticing because of
sharp rises or drops in the MFM scores. Specifically, the
changes relative to this patient were very different from those
of other patients with DMD involved in the study. His phenotype was less serious despite a confirmed diagnosis of DMD
(deletions in exons 5–7 within the dystrophin gene). This
patient lost his ability to walk when he was 14-years-old and
his total score had decreased by only 1.0% over the previous
19 months.
DISCUSSION
In our sample of patients with DMD, the measures of motor
function by MFM showed a continuous and exponential
decline with age, which is in agreement with previous results
on change in muscle strength in DMD.9,10 However, to monitor progression of DMD, evaluations of motor function are
needed as a complement to measurements of muscle strength.3
Indeed, the MFM can be administered to ambulant and nonambulant patients and each of its dimensions used to establish
profiles of physical impairment and changes over time. This is
an advantage over current tests of functional ability, such as
Use of Motor Function Measure in Duchenne Muscular Dystrophy Carole Vuillerot et al. 63
timed tasks, which are informative only a short period before
loss of ambulation. According to Allsop and Ziter, ‘Current
tests of functional ability are poor measures of disease progression during most of the ambulatory period, as efficiency
is maintained despite continuous decline in muscle strength.’9
Besides, functional grades, such as the lower-limb score of Vignos et al.11 and the upper-limb score of Brooke et al.,12 focus
only on one part of the body and their scores are probably not
very sensitive to change. To our knowledge, with the exception of the Hammersmith Motor Ability Scale,13 designed for
ambulant patients, and the EK scale, designed for non-walking
patients,14 no scale other than the MFM measures motor
function in patients with DMD, ambulant or not, whose sensitivity to change is known. Moreover, the acceptance of the
MFM among children was good, its administration time was
relatively short (36min on average), and its interrater variability was ‘good’ to ‘excellent’ for most items.4
This study assessed the ability of the MFM to detect the
loss over time of the motor performance of a patient with
DMD taking no medication. Over a 3-month period, despite
the small sample studied, D1 decreased significantly and, over
a 1-year period, all mean MFM scores decreased significantly.
However, in a small number of patients, subscore D3
increased, possibly reflecting the participants’ experience with
the test.
Although the annual decrease in the total score was 5.8%
for the whole group, indicating an overall decline in motor
capacities, examination of the D1, D2, and D3 subscores independently provided more information depending on the stage
of the disease. Indeed, in ambulant patients with DMD, D1
was the most informative dimension, with a mean decrease of
17.2% per year before loss of ambulation in patients aged 6
years and over. After loss of ambulation, D2 became the most
informative and showed an average decrease of 9.4% per year.
In patients over 14 years, the average decrease in D3 was
10.8% per year. D1 seems to be particularly interesting
because it is related to loss of ambulation and is responsive to
short-term changes (3mo). D2 and D3 would be of interest at
later stages of the disease. Whatever the patient’s age, the
MFM was able to identify patient ‘phenotypes’ (or motor
function characteristics) so that correlations with genotypes
may now be achieved. As there is a large spectrum of expressions of DMD, the MFM proved to be an interesting tool to
describe various phenotypes and disease progressions.
Compared with a control group, patients with DMD treated with steroids showed stabilization of the total score and of
the D2 subscore. Despite the small sample size in the present
study, the results showed that the MFM is a promising scale
to evaluate the effect of a treatment over a whole year. However, this result should be confirmed by a larger controlled
study.
Assessing the degree of physical impairment in patients
with DMD using the MFM may help to predict loss of
ambulation nearly a year before it occurs. This event is
expected but dreaded by the patients and their families, and
all need to be emotionally and financially prepared for it (e.g.
by getting an electronic wheelchair and adapting the home
64 Developmental Medicine & Child Neurology 2010, 52: 60–65
and the car). Although the age at loss of ambulation varies
greatly (around age 9y; range 6–14y in our group), it seems
possible to predict that a DMD patient will lose the ability to
walk within a year when D1 is close to 40% or the total score
is close to 70%.
The present results are also promising regarding the use of
the MFM in clinical trials to demonstrate either deterioration
of a patient’s condition or a possible improvement due to a
specific treatment. If short test forms are needed, we suggest
using D1 in younger patients who have not lost ambulation
and D2+D3 in non-ambulant patients. Furthermore, the present results make it possible to estimate the number of patients
to include in a prospective clinical trial. The number depends
on the study design, the required power, the hypothesis concerning the outcome, and the patients’ ability to walk. For
example, in a hypothesis of no change in motor function over
1 year in the active treatment group versus the control group,
with 5% alpha risk and 90% power, 15 patients per group are
needed for either total score or D1 score in walking patients,
but 45 patients per group are needed for total score or 50
patients per group for D2 score in non-walking patients. In a
hypothesis of 50% reduction in the mean score change over 1
year in the active treatment group versus the control group,
with 5% alpha risk and 90% power, 70 patients per group are
needed in walking patients but 190 patients per group for total
score or 170 patients per group for D2 score in non-walking
patients.
The two main limitations of our study are the small sample
sizes and the lack of an intermediate test at 6 months. We
hope further studies will confirm the ability of the MFM to
detect changes over 6 months, to predict loss of ambulation in
a larger number of patients, and to be used in clinical trials to
demonstrate intervention effects.
APPENDIX
Members of the MFM Collaborative Study Group
M Fournier-Méhouas MD, V Tanant PT (Hôpital de
l’Archet, Nice); F Beltramo MD, C Marchal, C Capello PT
(Hôpital Brabois, Nancy); D Fort MD, M Desingue PT (Centre de Rééducation Enfants, Flavigny sur Moselle); C Bérard,
I Hodgkinson MD, F Girardot, F Locqueneux PT (l’Escale,
Centre Hospitalier Lyon-Sud, Lyon); J Lachanat MD, D
Denis PT (Fondation Richard, Lyon); J Nielsen MD, C Glardon, S Igolen-Augros PT (Hôpital Orthopédique, de Lausanne, Switzerland); A Fares, G Le Claire, J L Le Guiet MD,
D Lefeuvre-Brule PT (Centre de Kerpape, Ploemeur); J Y
Mahé MD, C Nogues PT (Centre de Pen Bron, La Turballe);
L Feasson MD, A Jouve PT (Hôpital Bellevue, Saint Etienne);
M Schmuck MD (Service de Soins à Domicile, Roanne); P Kieny MD, G Morel PT (Résidence la Forêt, Saint Georges sur
Loire); J A Urtizberea, C Themar Noel, F Cottrel, V Doppler
MD, J Paulus PT (Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris); F Vandenborre MD, C Pastorelli PT (Hopital
Raymond Poincaré, Garches); I Desguerre MD (Hôpital
Saint-Vincent de Paul, Paris); E Boulvert MD (Centre de
rééducation Petit Tremblay, Corbeil-Essonnes); B Pialoux, P
Gallien MD, F Letanoux PT (Centre Hospitalier Régional
Pontchaillou, Rennes); P Dudognon, J Y Salle MD, F Parpeix,
P Morizio PT (Centre Hospitalier Universitaire Dupuytren,
Limoges); V Bourg MD, B Moulis-Wyndels PT (Centre Paul
Dottin, Ramonville Saint Agne); M Marpeau, F Barthel MD,
D Trabaud, D Rouif, M Vercaemer PT (Centre St Jean de
Dieu, Paris); G Viet MD, B Degroote PT (Hôpital Swinghedaw, Lille); A Carpentier MD, I Bourdeauducq PT (Centre
Marc Sautelet, Villeneuve d’Ascq).
ACKNOWLEDGEMENTS
This work was supported by the Association Française contre les
Myopathies (AFM). The Motor Function Measure (MFM) sensitivity
to change study, which required the completion of two tests a year
apart, was carried out by the members of the MFM Collaborative
Study Group (see Appendix at end of paper for list of members).
We are grateful to Robert Pangalila for his comments on the
manuscript.
SUPPORTING INFORMATION
Additional supporting information may be found in the online version
of this article:
Figure S1: Graphical representation of the study groups and subgroups.
Figure S2: Changes in motor function measure (MFM) subscore
D3 (distal motor capacity) at 1-year design interval according to age
in the 41 patients in the long-term study.
Please note: Wiley-Blackwell are not responsible for the content or
functionality of any supporting materials supplied by the authors. Any
queries (other than missing material) should be directed to the corresponding author of the article).
REFERENCES
1. Emery AE. Population frequencies of inherited neuromuscular diseases: a world survey. Neuromuscul Disord 1991; 1: 19–
29.
2. Sussman M. Duchenne muscular dystrophy. J Am Acad Orthop Surg 2002; 10: 138–51.
Validation study. Rev Neurol (Paris) 2006; 162: 485–93. (In
rapide: application au contrôle thérapeutique. Ann Med Phys
French)
1979; 23: 1–14.
6. MFM Collaborative Study Group. Motor Function Measure:
11. Vignos PJ, Spencer GE, Archibald KC. Management of pro-
User’s Manual. Evry, France: Association Française contre
gressive muscular dystrophy of childhood. J Am Med Assoc
les Myopathies, 2006.
1963; 184: 89–96.
3. Scott E, Mawson SJ. Measurement in Duchenne muscular
7. Liang M, Fossel A, Larson M. Comparison of five health-sta-
12. Brooke MH, Fenichel GM, Griggs RC, et al. Clinical investi-
dystrophy: considerations in the development of a neuromus-
tus instruments for orthopaedic evaluation. Med Care 1990;
gation in Duchenne dystrophy: 2. Determination of the
cular assessment tool. Dev Med Child Neurol 2006; 48: 540–
28: 632–42.
‘power’ of therapeutic trials based on the natural history.
44.
4. Bérard C, Payan C, Hodgkinson I, Fermanian J, The MFM
8. Bjorgvinsson T, Kerr P. Use of a common language effect
size statistic. Am J Psychiatry 1995; 152: 151.
collaborative study group. A motor function measure scale
9. Allsop KG, Ziter FA. Loss of strength and functional
for neuromuscular diseases. Construction and validation
decline in Duchenne’s dystrophy. Arch Neurol 1981; 38:
study. Neuromuscul Disord 2005; 15: 463–70.
406–11.
Muscle Nerve 1983; 6: 91–103.
13. Scott OM, Hyde SA, Goddard C, Dubowitz V. Quantification
of muscle function in children: a prospective study in Duchenne muscular dystrophy. Muscle Nerve 1982; 5: 291–301.
14. Steffensen BF, Lyager S, Werge B, Rahbek J, Mattsson E.
5. Bérard C, Payan C, Fermanian J, Girardot F, The MFM
10. Legrand-Persoz M, Persoz B, Boulvert E, Gros P, Dardel JP,
Physical capacity in non-ambulatory people with Duchenne
collaborative study group. The Motor Function Measure,
Arhan P. Surveillance de l’évolution musculaire respiratoire
muscular dystrophy and spinal muscular atrophy. A longitu-
a tool of clinical evaluation for neuromuscular diseases.
dans la myopathie de Duchenne de Boulogne à évolution
dinal study. Dev Med Child Neurol 2002; 44: 623–32.
Use of Motor Function Measure in Duchenne Muscular Dystrophy Carole Vuillerot et al. 65