title: Domains of Daily Physical Activity in Children with Mitochondrial Disease: A 3D Accelerometry Approach.
abstract: Feasible, sensitive and clinically relevant outcome measures are of extreme importance when designing clinical trials. For paediatric mitochondrial disease, no robust end point has been described to date. The aim of this study was to select the domains of daily physical activity, which can be measured by 3D accelerometry, that could serve as sensitive end points in future clinical trials in children with mitochondrial disorders.In this exploratory observational study, 17 patients with mitochondrial disease and 16 age- and sex-matched controls wore 3D accelerometers at the upper leg, upper arm, lower arm and chest during one weekend. Using the raw data obtained by the accelerometers, we calculated the following outcome measures: (1) average amount of counts per hour the sensors were worn; (2) the maximal intensity; (3) the largest area under the curve during 30 min and (4) categorized activities lying, standing or being dynamically active. Measuring physical activity during the whole weekend was practically feasible in all participants. We found good face validity by visually correlating the validation videos and activity diaries to the accelerometer data-graphs. Patients with mitochondrial disorders had significantly lower peak intensity and were resting more, compared to their age- and sex-matched peers.Finally, we suggest domains of physical activity that could be included when measuring daily physical activity in children with mitochondrial disorders, preferably using more user-friendly devices. These include peak activity parameters for the arms (all patients) and legs (ambulatory patients). We recommend using or developing devices that measure these domains of physical activity in future clinical studies.
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands. Saskia.koene@radboudumc.nl.
authors.forename: Saskia
authors.initials: S
authors.lastname: Koene
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands.
authors.forename: Ilse
authors.initials: I
authors.lastname: Dirks
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands.
authors.forename: Esmee
authors.initials: E
authors.lastname: van Mierlo
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands.
authors.forename: Pascal R
authors.initials: PR
authors.lastname: de Vries
authors.affiliation: Donders Center for Neuroscience, Department of Rehabilitation, Pediatric Physical Therapy, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Anjo J W M
authors.initials: AJWM
authors.lastname: Janssen
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands.
authors.forename: Jan A M
authors.initials: JAM
authors.lastname: Smeitink
authors.affiliation: Donders Center for Neuroscience, Department of Rehabilitation, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Arjen
authors.initials: A
authors.lastname: Bergsma
authors.affiliation: Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Essers
authors.affiliation: Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Meijer
authors.affiliation: Department of Paediatrics, Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, PO BOX 9101, Geert Grooteplein 10, Nijmegen, 6500 HB, The Netherlands.|Donders Center for Neuroscience, Department of Rehabilitation, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Imelda J M
authors.initials: IJM
authors.lastname: de Groot
keywords: 3D accelerometry; Children; Daily physical activity; Mitochondrial disease; Outcome measures