Revised Hammersmith Scale (RHS) for Spinal Muscular Atrophy

Original Editor - Evelin Milev Top Contributors - Evelin Milev and Amrita Patro


Objective

The Revised Hammersmith Scale (RHS) is specifically design outcome measure for people affected by Spinal Muscular Atrophy (SMA)[1] . The Hammersmith Functional Motor Scale (HFMS), was the first outcome measure designed to capture physical abilities in patients with SMA type 2 and 3[2]. An expanded version of the scale was published to be used for patients who were ambulant and it was named the Hammersmith Functional Motor Scale Expanded (HFMSE)[3]. In recent years specialist from all over the world who are working with patients with SMA collaborated together to develop a much better scale by using Rasch analysis. The new scale was called RHS and it provides more sensitive description of SMA phenotype and progression of disease.

Intended Population

The RHS was developed to evaluate the broad spectrum of motor functions in patients with SMA. It detects changes for very weak SMA type 2 to very strong SMA type 3. With some of the new pharmaceutical approaches which show great improvements in the weaker end of the spectrum, now there are even children with type 1 who show enough skills in order to pick up points on the scale.

Method of Use

The RHS is an ordinal scale which consist of 33 items with grades of 0,1 and 2. For individuals who can achieve the task without any compensation it is given a score of 2. For those who only attempt the movement or finish it with some form of compensation is scored 1 and sore of 0 is given when patients are unable to perform any part of the item.

Evidence

The Revised Hammersmith Scale has been performed on 138 subjects before and it showed very good fit for all of the items[1]. However, it should be noted that the scale is designed to capture a population with a broad spectrum of physical abilities including both ambulant and non-ambulant patients with SMA.

Reliability

The reliability is reported as good with a high Person Separation index (PSI) of 0.98 and a minimum ceiling effect.

Validity

The RHS has been correlated with the WHO motor milestones showing that the scale captures progressively more difficult motor abilities. Thus, the scale is deemed to possess an established concurrent validity. The RHS also demonstrated discriminative groups validity by distinguishing between SMA type, ambulant status and current WHO functional score.

Links

The published article with all relevant worksheets and supporting information can be found here.

References

  1. 1.0 1.1 Ramsey D, Scoto M, Mayhew A, Main M, Mazzone ES, Montes J, et al. (2017) Revised Hammersmith Scale for spinal muscular atrophy: A SMA specific clinical outcome assessment tool. PLoS ONE 12(2): e0172346. doi:10.1371/journal. pone.0172346
  2. Main M, Kairon H, Mercuri E, Muntoni F. The Hammersmith Functional Motor Scale for Children with Spinal Muscular Atrophy: a Scale to Test Ability and Monitor Progress in Children with Limited Ambulation. European Journal of Paediatric Neurology. 2003;7(4):155–9. pmid:12865054
  3. O'Hagen JM, Glanzman AM, McDermott MP, Ryan PA, Flickinger J, Quigley J, et al. An expanded version of the Hammersmith Functional Motor Scale for SMA II and III patients. Neuromuscular disorders: NMD. 2007;17(9–10):693–7. Epub 2007/07/31. pmid:17658255