The best muscletest for Duchenne muscular dystrophy;
Outcome measures for Duchenne muscular dystrophy trials

Duchenne muscular dystrophy is an X-linked genetic disorder, caused by a
mutation in the dystrophin gene. This protein has an important function in
maintaining the stability of the muscle membrane. In Duchenne muscular
dystrophy this dystrophin is absent, leading to contraction-induced muscle
damage. Clinically, this leads to progressive muscle weakness, causing
wheelchair dependance from approximately the age of ten and death due to
respiratory failure or a cardiomyopathy around the age of 20 in untreated
patients. At this moment there are many research developments into a possible
treatment for this untreatable muscle disease. The use of reliable and
sensitive outcome measures in future trials is of great importance.
Unfortunately, there is no consensus about which outcome measure to use in
Duchenne muscular dystrophy. The present study aims to investigate which tests
are usable as outcome measures for development of therapies in Duchenne
muscular dystrophy.

1. Assessment of sensitivity of several outcome measures in muscle force and
function in Duchenne muscular dystrophy
2. Assessment of reproducability of different outcome measures
3. Assessment of clinical relevance of measured change over time in different
outcome measures.

Prospective, observational study. Inclusion of patients is achieved through the
dystrophinopathy database in the LUMC and through the ALADIN (All Against
Duchenne In the Netherlands) consortium. The expected duration of the study is
2 years.

Participants are being asked to visit the LUMC three times, with intervals of
six months. During these visits several tests are being undertaken assessing
muscle strength, muscle function and lungfunction: Manual Muscle Testing,
Quantitative Muscle Testing, Six Minute Walk Test, Timed Function Tests, North
Star Ambulatory Assessment and Lungfunction Tests (FVC, MIP, MEP). Before each
testday, participants are also asked to complete a questionaire about quality
of life and to indicate change in muscle strength, muscle function, walking and
lungfunction since the previous testing day.
The riscs during participation consists of the change to vall during one of the
tests. The consequences of a possible fall are being minimized by using a soft
surface if possible and by escorting the participant during the Six Minute Walk
Test to support/catch him in case of a fall.