Our researchers have improved the way in which we use the ALSFRS-R scale which will more accurately measure the progression and severity of ALS.

Measuring the progression of ALS

Our researchers have improved the way in which we use the ALS function rating scale (ALSFRS-R), which is used to measure the severity and progression of ALS.

The scale includes 12 questions that have a score of zero to four, where zero indicates no function and four indicates full function. This provides a total score out of 48.

It is useful for diagnosing people with the disease, measuring how it is progressing, and can also be helpful for selecting participants for clinical trials.

However, the scale is known to have some issues, and researchers looked at ways to improve the scale so that the results are more accurate.

Understanding how the scale works

Dr Carolyn Young and the TONiC team, based at the Walton Centre NHS Foundation Trust, recruited 1000 people living with ALS from 35 UK clinics to better understand how the scale works.

They used statistical techniques, called confirmatory factor analysis and Rasch analysis, and assessed how well the questions on the survey measured what they’re supposed to as well as how difficult each question is.

Using the two analyses, the team found that the overall score wasn’t reliable. Mostly because the scale measures multiple different things, such as speech or handwriting, and not just one aspect.

Professor Carolyn Young, who led the study and is one of our programme leads, explained: “The amazing contribution from people living with ALS meant that we had enough research volunteers to verify the results in two independent groups and to publish a conversion table so anyone can convert the original ALSFRS-R total to an interval equivalent. Interval level data is hugely important for research into treatments and care because it enables assessment of change. After all, how can we judge what is working unless we can measure disability and how it’s changing over time.”

Improving how the scale works

Using the original overall score can give misleading results and it can miss small changes at the ends of the scale and exaggerate changes in the middle.

The team then used a complex statistical method that adjusted the scoring system and made it more accurate. With this new method, reliable scores were collected for most parts of the test, such as speech and motor function, but not for breathing.

The adjusted scoring more accurately reflects the experience of people living with the disease, which will help diagnose the disease and better inform clinical trials.

Professor Chris McDermott, who is co-chair of the MND Research Institute, added: “We are increasingly recognising that the way clinical trials in MND are carried out needs to change if we are to be certain to avoid false signals. A real problem in the field has been promising signals in Phase 2 trials that are not replicated in Phase 3 studies. The ALSFRS is the main outcome measure used and it is clear for many years we have been using it in the wrong way. The UK MNDRI work led by Professor Young clearly demonstrates this and gives a way forward to use ALSFRS in the correct way.”

You can read about our other blogs and news stories here or read about our research here.