What is the Multiple Sclerosis interactive Digit Modality Test or MSiDMT?
Rod Middleton, Project Manager and System Architect of the UK MS Register, talks about the development of the test and its importance for future MS assessments.
The UK MS Register has recently been working with Imperial College London and Swansea Bay University Health Board to create a new electronic measure of cognition, which we’ve called the Multiple Sclerosis interactive Digit Modality Test or MSiDMT. It’s based on a commonly used paper test which has been shown to be a reliable measure of brain function in multiple sclerosis (MS) called the Symbol Digit Modality Test or SDMT. This existing, copyrighted and proven, paper-based assessment has been around since the early 70s and is still widely used today.
More comprehensive clinical assessment
Measurements of cognition in multiple sclerosis are generally confined to paper and verbal assessments which can take a large amount of time and are rarely employed in routine clinical practice. This electronic tool has been designed to replicate the SDMT, which measures two main things; working memory and speed of processing. Participants match symbols to numbers against the clock. Scoring as many correct matches as possible over 90 seconds.
This work delivers an electronic cognitive test which can be easily used in either the clinic or in the patients’ home. It will encourage repeated, accurate recording of patient’s cognition which will be extremely valuable for research and beneficial for clinical practice.
Initially the electronic version will be deployed to iPads only, with the aim to roll out to all participants’ devices.
Completing the test
Nine different symbols are displayed at the top of the screen with corresponding numbers, 1-9, underneath. Upon each launch of the app, the symbols are randomised from over 350,000 possible combinations. The centre of the screen displays two of the symbols; the one to be identified now, and the one that’s next. At the bottom of the screen there are a number of ‘buttons’, again labelled 1-9 that participants tap to match the symbol with the corresponding number from the key above.
Trialling the app
108 people with MS were recruited to trial the app, of whom, 28 returned within one month for a repeat test. We did this across two UK MS centres; Morriston Hospital in Swansea and Charing Cross Hospital in London. All participants completed the written paper SDMT test prior to the MSiDMT for comparison. Test environments were controlled for noise and disturbance.
We found that the SDMT and MSiDMT scores were closely correlated and were consistent in the 1 month retest values. Lower scores were seen in patients with higher age and disability which is also consistent with the paper version.
We presented our work at this year’s ECTRIMS conference in Stockholm this September. ECTRIMS is the world’s largest congress of MS researchers. Based on the proven history of this assessment as an effective outcome measure in a number of trials and now the ease at which it can be done, we hope that this will be a valuable resource for clinicians for future MS assessments.
One of our centres of excellence, The UK MS Register was launched in 2011 by Population Data Science at Swansea University Medical School and is funded by the MS Society. The fundamental concept is to capture more real world data about living with MS in the United Kingdom. The Register does this in two ways; People with MS record information about their MS via simple questionnaires on our website. The second is to link consented website participants’ medical records with their questionnaire responses. This provides an extremely rich bank of data and huge potential for research.