In 2014 the original scale and several other SMA scales received some criticism regarding how well they met a number of measurement criteria i.e. how well it measures the physical abilities of those with SMA, how well the scoring works, how reliable the scale was etc. and it was recommended that the scale and others required revision (Cano et al, 2014). At that time SMA clinical trials were increasing and we were entering a time where instead of a disease which could be described as having initial period of decline followed by relative stability there may be the potential for people with SMA to improve.
Therefore an international SMA consortium consisting of SMA REACH UK, the Italian SMA Network and the PNCRN for SMA (USA) networks met to review and enhance the Hammersmith Scale so that it was fit for purpose for today's climate. This resulted in the development of the Revised Hammersmith Scale for SMA (RHS). Each item and it's scoring was derived following in depth discussion by a panel of SMA experts and then tested in several pilots until the final, published, version was created.
The RHS consists of 36 items which test those with SMA type 2 who may have lost the ability to sit through to very strong people with SMA type 3. The maximum achievable score is 69. The scoring has been rigorously tested with complex psychometric tests in a large international pilot of 138 people with SMA. It also includes two timed tests to really test those with stronger abilities. It also includes reference to the World Health Organisation motor milestones which are currently used in clinical trials. The manual (including the testing form) can be found here, and the published article (which also includes the testing form) is free to download and access from the PLOS ONE website.
Danielle Ramsey, 7th May 2017