Validation of motor and functional scales for the evaluation of adult patients with 5q spinal muscular atrophy

Autores de IIS La Fe

• Juan Francisco Vázquez Costa

  Autor

• Nuria Muelas Gómez

  Autor

• Nancy Carolina Ñungo Garzón

  Autor

• Inmaculada Pitarch Castellano

  Autor

• 

  Teresa Sevilla Mantecón

  Autor

• David Hervás Marín

  Autor

Participantes ajenos a IIS La Fe

• Povedano M.
• Nascimiento-Osorio A.E.
• Moreno Escribano A.
• Kapetanovic Garcia S.
• Dominguez R.
• Exposito J.M.
• González L.
• Marco C.
• Medina Castillo J.
• Natera de Benito D.

Grupos

• Patología Neuromuscular y Ataxias

Abstract

Background and purpose: Mos scales currently used to evaluate spinal muscular atrophy (SMA) patients have only been validated in children. The aim of this study was to assess the construct validity and responsiveness of several outcome measures in adult SMA patients. Methods: Patients older than 15 years and followed up in five referral centres for at least 6 months, between October 2015 and August 2020, with a motor function scale score (Hammersmith Functional Motor Scale Expanded [HFMSE], Revised Upper Limb module [RULM]) were included. Bedside functional scales (Egen Klassification [EK2], Revised Amyotrophic Lateral Sclerosis Functional Rating Scale [ALSFRS-R]) were also collected when available. Spearman's rho correlations (rs) and Bangdiwala's concordance test (B) were used to evaluate the scales' construct validity. Monthly slopes of change were used to calculate their responsiveness of the scales. Results: The study included 79 SMA patients, followed up for a mean of 16 months. All scales showed strong correlations with each other (rs > 0.70). A floor effect in motor function scales was found in the weakest patients (HFMSE < 5 and RULM < 10), and a ceiling effect was found in stronger patients (HFMSE > 60 and RULM > 35). The ALSFRS-R (B = 0.72) showed a strong ability to discriminate between walkers, sitters and non-sitters, and the HFMSE (B = 0.86) between walkers and sitters. The responsiveness was low overall, although in treated patients a moderate responsiveness was found for the ALSFRS-R and HFMSE in walkers (0.69 and 0.61, respectively) and for EK2 in sitters (0.65) and non-sitters (0.60). Conclusions: This study shows the validity and limitations of the scales most frequently used to assess adult SMA patients. Overall, bedside functional scales showed some advantages over motor scales, although all showed limited responsiveness. © 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.

Keywords

• Adult; Child; Humans; Muscular Atrophy, Spinal; Outcome Assessment, Health Care; Spinal Muscular Atrophies of Childhood; Upper Extremity; nusinersen; salbutamol; adult; Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised; Article; clinical evaluation; cohort analysis; construct validity; controlled study; convergent validity; discriminant validity; Egen Klassification; female; floor effect; follow up; forced vital capacity; functional assessment; Hammersmith Functional Motor Scale Expanded; human; Kugelberg Welander disease; longitudinal study; major clinical study; male; motor performance; observational study; prospective study; rating scale; Revised Upper Limb module; sitting; six minute walk test; spinal muscular atrophy; spinal muscular atrophy type 2; spinal muscular atrophy type 4; validation study; walking; child; hereditary spinal muscular atrophy; spinal muscular atrophy; upper limb