Mapping the Longitudinal, Multidimensional Impact of MS in Relation to Variables Indicative of Neurological Reserve

Primary outcomes

1. EDSS

   Time frame: 2 years

   The EDSS ranges from 0 to 10 in 0.5 unit increments that represent higher levels of disability. In the lower part of its range, the EDSS score predominantly reflects the result of the examination by a neurologist, primarily a measure of impairment in eight functional systems (FS). In the middle part of its range, the EDSS score is primarily a measure of ambulation ability. At the higher end, upper limb and bulbar function as well as the ability to accomplish activities of daily living determine the score. The EDSS is considered to be an ordinal scale. The point estimates of the central tendency should be presented as median values and the measures of dispersion as interquartile ranges (Uitdehaag B, 2014).

   According to Havardova et al, MSJ 2017, the following disease severity groups can be distinguished:

   Mild EDSS 0-3 Moderate EDSS 4-6.5 Severe EDSS 7-9

2. Functional tests

   Time frame: 2 years

   Functional tests of upper limbs (9-HPT) and lower limbs (25FWT) are measured in seconds. Higher scores indicate a worse function. A 20% change of the scores is considered to be a reasonable cutoff value for reliably detecting a clinically meaningful change.

3. Cognitive tests

   Time frame: 2 years

   Cognitive screening tests include the PASAT (till 2015) and the SDMT (since 2015). The results are corresponding to the number of correct answers in a fixed time frame. Higher scores indicate a better function. The tests were usually performed on a yearly basis to limit learning effects.

4. The EQ-Visual Analog Score (EQ-VAS)

   Time frame: 2 years

   The EQ-Visual Analog Score (EQ-VAS) records the patient's self-rated health on a vertical visual analogue scale, a kind of 'thermometer' where the endpoints are labelled 'The best health you can image' (endpoint 100 at the top) and 'The worst health you can image' (endpoint 0 at the bottom). The patient is asked to draw a line from the box marked 'Your health status today' to the appropriate point on the 'thermometer' scale. The VAS can be used as a quantitative measure of health outcome that reflects the patient's own judgement.

   The 5-level EQ-5D version (EQ-5D-5L) was introduced by the EuroQol Group in 2009 to improve the instrument's sensitivity and to reduce ceiling effects, as compared to the EQ-5D-3L. Five questions assessing five domains (mobility, self-care, usual activity, pain/discomfort, anxiety/depression) are included. A single index value can be generated.