Fig 1.
Revised Hammersmith Scale for Spinal Muscular Atrophy: Process of development.
Iterative process of RHS development—expert panel, SMA outcome measure review, draft instrument, scale pilot and subsequent modification summarised for draft version 1, 2 and final version of the RHS.
Fig 2.
Discriminative/groups validity of the RHS.
Median RHS total score (IQR and Range) versus a) SMA type combined with current ambulatory status; b) Highest current level of motor ability according to WHO groups.
Table 1.
RHS Pilot sample demographics and discriminative/groups validity.
Fig 3.
Individual RHS total score data points versus age and SMA type for entire pilot cohort (n = 138).
RHS total score versus age and stratified according to SMA type, * ambulant and ° non-ambulant patients are distinguished, dotted lines represent floor (RHS total score = 0) and ceiling effect (RHS total score = 69).
Table 2.
Age stratification versus median RHS score (IQR).
Table 3.
Individual item fit for RHS in order of difficulty.
Table 4.
Overall properties of RHS using the Rasch measurement method.
Fig 4.
Rasch analysis: RHS 17.03.2015 threshold map for items in RHS in ranked order of difficulty.
The presence of horizontal bars indicates that for these items as an individual’s ability increases they would be more likely to achieve a higher score and that this would increase systematically in a logical progression. They would first score 0, then 1 and then 2 as ability improves. The inverse is also true. Within each bar a number 1 represents a score of 0 on the RHS, 2 represents a score of 1, and 3 represents a score of 2.
Fig 5.
Rasch analysis: RHS 17.03.2015 person item threshold distribution.
Targeting of the patient sample (top) to individual items (bottom). The figure shows the targeting between the distribution of person measurements (upper histogram) and the distribution of the item locations (lower histogram).
Table 5.
SMA Type 3 sub analysis: RHS timed tests (all SMA 3a).