As the number of systematic reviews grows, there is an increasing need for overviews in which the findings from multiple reviews in the same general area is brought together. This happened for symptomatic treatments for motor neurone disease in January 2017 and lead author on this new Cochrane Overview, Louisa Ng from the Royal Melbourne Hospital in Australia spoke with Brian Dickie from the UK Motor Neurone Disease Association about the evidence.
John: Hello, I'm John Hilton, editor of the Cochrane Editorial unit. As the number of systematic reviews grows, there is an increasing need for overviews in which the findings from multiple reviews in the same general area is brought together. This happened for symptomatic treatments for motor neurone disease in January 2017 and lead author on this new Cochrane Overview, Louisa Ng from the Royal Melbourne Hospital in Australia spoke with Brian Dickie from the UK Motor Neurone Disease Association about the evidence.
Brian: Good morning Louisa, thanks for agreeing to have a chat about the new overview. As you know motor neuron disease, or MND, which is also known as amyotrophic lateral sclerosis (ALS), is an uncommon, incurable disease that affects the nerves involved in movement. It gets worse over time and people with MND experience a wide range of symptoms, including progressive disability pain, spasticity, cramps, swallowing problems and difficulty breathing. I’m hoping that your overview might help, so could you begin by telling us a little about why you did it?
Louisa: Good morning Brian. It is lovely to speak with you today. There are currently nine Cochrane reviews that cover the effectiveness of a wide range of symptomatic treatments in MND. Our main aim of the overview was to make this information more accessible and user-friendly..,. Before I launch into what we found, it’s important to note a few things. Firstly, sometimes clinical trials may fail to show that a treatment is effective for reasons that are not related to the true effects of the treatment itself. For example, there might be too few people in a trial…., or an ineffective dose of a drug might have been used. Secondly, this overview is not as comprehensive as we would have liked -- we weren’t able to cover many symptoms in MND, such as cognitive and behavioural impairment and pseudobulbar emotional lability because these symptoms were not covered in any of the current reivews. Finally, symptomatic treatment in MND is very challenging to study. MND is relatively rare, has varied clinical presentations, and often results in a rapidly disabling population with high mortality rates which means that the type of study we usually prefer for comparing the effects of interventions, the randomised trial, is uncommon. All of these factors mean that reviews focused on trials can still struggle to provide clear conclusions for practice.
Brian: That’s a good scene setter for what I expect was quite a challenging overview to do, and given the range of symptoms experienced by people with MND I expect that there are many different treatments that have been studied, and perhaps many still needing to be studied. This is particularly important because much can be done to manage symptoms, to enable people with MND to maintain independence for as long as possible and to help them and their families deal with the emotional impact of MND but it can often be challenging to choose between various treatments whilst still grappling with the diagnosis. So, what did you find?
Louisa: If I start with symptoms that are commonly treated with medications, such as pain management; there are currently many treatments in clinical use for pain, but no robust information currently exists specifically for people with MND. As for cramps, there is evidence that memantine and tetrahydrocannabinol (active component of cannabis) are probably ineffective for cramps and that vitamin E may be ineffective. There is too little information from randomised trials on the effects of other drugs, including L-threonine, gabapentin, xaliproden, riluzole, and baclofen. We should also bear in mind that many of these trials were not primarily designed to look at improvement of cramps as an outcome.
Brian: What about treatments for bulbar and respiratory symptoms?
Louisa: We’ve found that non-invasive mechanical ventilation probably improves survival and quality of life and that a single session of botulinum toxin injections into the salivary glands probably reduces excessive saliva production and dribbling. As for tube feeding for supporting nutrition, at present, there is no evidence from controlled trials to indicate whether or not there is a benefit.
Brian: And, how about exercise which I know that many people ask about?
Louisa: Based on the current evidence, it‘s uncertain whether exercise improves muscle stiffness or spasticity. There is, however, some suggestion that it may improve disability but not quality of life. There was also a lack of evidence on multidisciplinary care or other treatments, but we need to be careful that this is not interpreted as them being ineffective. Without the necessary evidence we cannot be sure one way or the other. However, by doing this Overview we have been able to bring together the existing evidence into a single place, which we hope will make it easier for people making choices about the various treatments, and highlight the areas that need more research.
Brian: It certainly will help and, as you say, we do need to see more high quality research to determine which treatments help to manage symptoms for those living with MND. Getting this evidence and making it available in a single place will help people with MND take more control, with the support of their families, health professionals and consumer organisations; so thanks very much for starting this process with the new Cochrane Overview.
Louisa: Thanks Brian, and, yes, as the evidence evolves we will be coming back to the overview and keeping it up-to-date.
John: If you would like to find the current version of the overview and future updates, you can find it online at Cochrane Library dot com. Just go to the website and type in a simple search for ‘overview of MND’.