Jean-Yves Hogrel1, Valérie Decostre2, Isabelle Ledoux2, Marie de Antonio2, Erik H Niks3, Imelda de Groot4, Volker Straub5, Francesco Muntoni6,7, Valeria Ricotti7, Thomas Voit6,7, Andreea Seferian2, Teresa Gidaro2, Laurent Servais8,9. 1. Institute of Myology, GH Pitié-Salpêtrière, 75651, Paris Cedex 13, France. jy.hogrel@institut-myologie.org. 2. Institute of Myology, GH Pitié-Salpêtrière, 75651, Paris Cedex 13, France. 3. Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands. 4. Department of Rehabilitation, Donders Center for Medical Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands. 5. The John Walton Muscular Dystrophy Research Centre, Newcastle Upon Tyne, UK. 6. Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London, London, UK. 7. NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London, UK. 8. Centre de Référence Des Maladies Neuromusculaires, CHU de Liège, Liège, Belgium. 9. Department of Paediatrics, MDUK Neuromuscular Center, University of Oxford, Oxford, UK.
Abstract
OBJECTIVE: The main aim was to explore the changes in hand-grip strength in patients with Duchenne muscular dystrophy (DMD) aged 5-29 years. Secondary aims were to test the effect of mutation, ambulatory status and glucocorticoid use on grip strength and its changes over time and to compute the number of subjects needed for a clinical trial to stabilize grip strength. METHODS: The analysis was performed on data collected during five international natural history studies on a cohort of DMD patients. Two hundred and two patients with genetically proven DMD were pooled from five different natural history studies. Excepting 13 patients with only one visit, the mean duration of follow-up was 2.2 ± 1.6 years. A total of 977 measurement points were collected. Grip strength was measured on the dominant side with a high precision dynamometer. The analysis was performed using absolute values and normalized values expressed in percentage of predicted values for age. RESULTS: For absolute values, grip strength typically increased in ambulatory boys and decreased in non-ambulatory patients. However, when normalized, grip strength was already reduced at age 5 years and thereafter continued to fall away from normal values. The weaker the patients, the less strength they are prone to lose over again. INTERPRETATION: Grip strength constitutes a sensitive and continuous outcome measure that can be used across all stages of DMD. Its measurement is easy to standardized, can be used in ambulatory and non-ambulatory patients and does not present any floor or ceiling effect. It is thus attractive as an outcome measure in therapeutic trials.
OBJECTIVE: The main aim was to explore the changes in hand-grip strength in patients with Duchenne muscular dystrophy (DMD) aged 5-29 years. Secondary aims were to test the effect of mutation, ambulatory status and glucocorticoid use on grip strength and its changes over time and to compute the number of subjects needed for a clinical trial to stabilize grip strength. METHODS: The analysis was performed on data collected during five international natural history studies on a cohort of DMDpatients. Two hundred and two patients with genetically proven DMD were pooled from five different natural history studies. Excepting 13 patients with only one visit, the mean duration of follow-up was 2.2 ± 1.6 years. A total of 977 measurement points were collected. Grip strength was measured on the dominant side with a high precision dynamometer. The analysis was performed using absolute values and normalized values expressed in percentage of predicted values for age. RESULTS: For absolute values, grip strength typically increased in ambulatory boys and decreased in non-ambulatory patients. However, when normalized, grip strength was already reduced at age 5 years and thereafter continued to fall away from normal values. The weaker the patients, the less strength they are prone to lose over again. INTERPRETATION: Grip strength constitutes a sensitive and continuous outcome measure that can be used across all stages of DMD. Its measurement is easy to standardized, can be used in ambulatory and non-ambulatory patients and does not present any floor or ceiling effect. It is thus attractive as an outcome measure in therapeutic trials.
Authors: Andrew Hooyman; Joshua S Talboom; Matthew D DeBoth; Lee Ryan; Matthew J Huentelman; Sydney Y Schaefer Journal: Dev Neuropsychol Date: 2021-10-06 Impact factor: 2.113