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Revised Hammersmith Scale for spinal muscular atrophy: Inter and intra-rater reliability and agreement

Lookup NU author(s): Dr Anna Mayhew, Professor Volker StraubORCiD, Dr Chiara Marini Bettolo



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Copyright: © 2022 Ramsey et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The Revised Hammersmith Scale (RHS) for Spinal Muscular Atrophy (SMA) was designed as a psychometrically robust clinical outcome assessment to assess physical abilities of patients with type 2 and 3 SMA. The reliability properties of the RHS have not yet been reported. A prospective RHS reliability study was undertaken in a UK cohort of experienced neuromuscular paediatric Physiotherapists. Reliability testing was conducted via a virtual survey platform two weeks apart. Through the virtual platform participants scored videos of two RHS assessments, one of a child with SMA 2 and one of a child with SMA 3. Inter and intra-rater reliability was analysed using a type 3 Intraclass Correlation Coefficient (ICC). Intra-rater agreement was further analysed using Bland Altman (BA) Limits of Agreement (LOA) and plots. The acceptable inter and intra-rater variability was set as a change of ± 2 by the international team of expert physiotherapists who developed the RHS. Inter-rater agreement, n = 22 raters, type 3 ICC was 0.989 (95% CI 0.944 to 1.00), 97.7% of scores were within the acceptable limits of ± 2 points. Intra-rater agreement, n = 21 raters, type 3 ICC ranged from 0.922 to 1.0, with 97.6% of scores within the acceptable limits of ± 2 points. The mean SMA 2 intra-rater difference was -0.10 (-0.6 to 0.4), with lower LOA -2.24 and upper LOA +2.04. Intra-rater difference between tests for SMA 3 intra-rater difference was -0.05 (-0.6 to 0.5), with lower LOA -2.48 and upper LOA +2.38. Intra-rater scoring precision fell within BA agreement limits of ±2 points. The results demonstrate that the RHS is highly reliable when used by experienced UK physiotherapists, and variability of test scores regarding inter and intra-rater reliability was confirmed to lie within ±2 points.

Publication metadata

Author(s): Ramsey D, Ramdharry G, Scoto M, Muntoni F, Wallace A, Mayhew A, Main M, Mazzone E, Montes J, Mayhew A, Straub V, Marini-Bettolo C, Parasuraman D, Majumdar A, Vijayakumar K, Horrocks I, Childs A-M, Spinty S, Wraige E, Gowda V, Hughes I, Chow G, Willis T, Ramdas S, deGoede C, Ong M, Illingworth M, Hussain N, Stephens E, Krishnakumar D

Publication type: Article

Publication status: Published

Journal: PLoS ONE

Year: 2022

Volume: 17

Issue: 12

Online publication date: 21/12/2022

Acceptance date: 28/11/2022

Date deposited: 16/06/2023

ISSN (electronic): 1932-6203

Publisher: Public Library of Science


DOI: 10.1371/journal.pone.0278996

PubMed id: 36542615


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