NorthStar Duchenne muscle function test deemed suitable for large clinical trials

Published Date
Reason Digital

It has been shown that experienced paediatric physiotherapists can, with relatively minimal training, reliably use the NorthStar Ambulatory Assessment in a clinical setting. The test, which was developed as part of the Muscular Dystrophy Campaign’s NorthStar project, was shown to be quick to carry out and could be accurately scored by many examiners. This makes it ideal for use in studies which are based at several locations.


What is the NorthStar Ambulatory Assessment?

The NorthStar Ambulatory Assessment (NSAA) is a clinical evaluation tool designed specifically for children with Duchenne muscular dystrophy. The protocol sets out a standard way for clinicians to assess the ability of the child to perform 17 activities, including standing, head-raising, hopping, and running.

Why was the development of the assessment important?

Three main ingredients are required for a clinical trial of a potential treatment to go ahead:

  • patients suitable for the trial must be available
  • a network of clinicians to administer the treatment and assess their benefit must be in place
  • clinicians must have reliable methods for testing whether a treatment is working. These methods must be able to be consistently performed at several different trial locations.

The first two components are being addressed by Treat-NMD, a European network for advancing treatments for people with muscle disease. The development of the NorthStar Ambulatory Assessment aims to address the third point.

What did the research show?

This piece of research was done as part of a continuing project to get the protocol ready for use in clinical studies. Researchers wanted to evaluate the reliability of the NSAA across a number of specialist clinical centres, and to discover the appropriate amount of training needed by examiners to correctly perform the assessment during large clinical trials.

They found that just two training sessions using videos and demonstrations were enough to accurately teach examiners how to perform the NorthStar Ambulatory Assessment test to a high standard. Assessments on children with muscular dystrophy could be completed in less than 15 minutes and results were comparable between different examiners. This means that after appropriate training the NorthStar Ambulatory Assessment can be easily and reliably performed by more than one examiner; something necessary in the running of large clinical trials.

Examiners were still able to accurately carry-out and score the test one month after the training sessions, suggesting that standards of assessment can be maintained even over longer periods of time.

What does this mean for patients?

Steroids are currently the main treatment for Duchenne muscular dystrophy, however many new therapies such as exon skipping gene-therapy are in development and are entering clinical trials. Better and more reliable methods of measuring severity of muscular dystrophy disease in both new patients and in patients taking part in clinical trials are needed in order to accurately determine any improvement in symptoms after treatment.

With the functional benefits seen in children with Duchenne muscular dystrophy who are taking a course of steroid treatment, some of the previously available scales missed the higher functional abilities (such as jumping and running) which some of these children may be capable of. The NorthStar Ambulatory Assessment test is thought to be better at measuring the overall condition of patients with Duchenne muscular dystrophy who still have a high level of mobility.

As children are able to complete the assessment easily and quickly in less than 15 minutes, compliance with the test is generally good and fatigue less of a problem.

Elaine Scott, NorthStar project coordinator said:

Initial investigation of the literature showed that there was a lack of reliable and valid measures for the assessment children with Duchenne muscular dystrophy who can still walk. The North Star project therefore decided to address this, which involved a lengthy process of study and review by specialist paediatric physiotherapists in the UK and resulted in the development of the new scale – the ‘North Star Ambulatory Assessment’. Reliability studies in the UK have shown good levels of agreement.

The NSAA has been in use by the clinical network for a number of years now, with data being entered into the national database as part of the information collected to assist in review and evaluation of clinical practice. This functional test is one part of the comprehensive physiotherapy and medical assessment protocol developed for the North Star Project. Other physiotherapy tests include manual muscle testing, myometry, pulmonary function testing and assessment of joint range of movement.

This article by Mazzone et al, whose lead author undertook training in the UK by specialist neuromuscular physiotherapists and the North Star Project coordinator, further supports the use of the North Star Ambulatory Assessment in the evaluation of patients and in its potential use for clinical trials.

Background information about the NorthStar project

The Muscular Dystrophy Campaign initiated The NorthStar project in 2003 and fully funds the project. The project aims to improve care standards for boys and young men with Duchenne muscular dystrophy.

To do this, the project has created a national NorthStar database which collects and stores clinical information from participating Duchenne muscular dystrophy clinics (after patient consent has been given). This is particularly useful as Duchenne muscular dystrophy is a relatively rare condition and more clinical information is desperately needed to help improve treatment of the condition.

A major achievement of the NorthStar project has been the development of the NorthStar clinical network of consultants, physiotherapists and health professionals based at specialist centres across the UK. The network members have already successfully worked together to produce standard guidelines on the use of steroids (glucocorticoid corticosteroids) in Duchenne muscular dystrophy.

Further information and links

More information about Duchenne muscular dystrophy.

Find out more about the NorthStar Project activities.

The original paper was published in Neuromuscular Disorders and is available by subscription only. The reference for the paper is:
Mazzone ES, et al. Reliability of the North Star Ambulatory Assessment in a multicentric setting. Neuromuscul Disord. 2009 Jul;19(7):458-61.

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