Anjo J.W.M. Janssen

Motor learning and working memory in children born preterm: A systematic review

Children born preterm have a higher risk for developing motor, cognitive, and behavioral problems. Motor problems can occur in combination with working memory problems, and working memory is important for explicit learning of motor skills. The relation between motor learning and working memory has never been reviewed. The goal of this review was to provide an overview of motor learning, visual working memory and the role of working memory on motor learning in preterm children. A systematic review conducted in four databases identified 38 relevant articles, which were evaluated for methodological quality. Only 4 of 38 articles discussed motor learning in preterm children. Thirty-four studies reported on visual working memory; preterm birth affected performance on visual working memory tests. Information regarding motor learning and the role of working memory on the different components of motor learning was not available. Future research should address this issue. Insight in the relation between motor learning and visual working memory may contribute to the development of evidence based intervention programs for children born preterm.

Influence of behaviour and risk factors on motor performance in preterm infants at age 2 to 3 years.

The aim of this cross‐sectional study was to determine the influence of test‐taking behaviour and risk factors for delayed motor performance in 437 preterm infants (244 males, 193 females; ≤32 weeks of gestation) at the corrected age of 2 to 3 years (mean 29mo [SD 3.3]). Other mean (SD) sample demographics were: postmenstrual age 29+5 weeks (1+5), range 25+0–32+0; birthweight 1213.7g (331.7), range 468–2350; and days in the neonatal intensive care unit 21.1 (21.3), range 1–165. Children (n=23) with a severe disability were excluded. We assessed motor performance and behaviour during testing with the Motor Scale and the Behaviour Rating Scale (BRS) of the Bayley Scales of Infant Development, 2nd edition (BSID‐II). Risk factors were tested against delayed motor performance as the dependent variable in binary logistic regression analysis. Median score on the Motor Scale in terms of the BSID‐II Psychomotor Developmental Index (PDI) was 86. ‘Delayed’ motor performance was observed in 46.5% of the children tested, and behaviour was ‘not‐optimal’ in 31.4%. The Motor Scale and BRS scores were significantly correlated (rs=0.62, p<0.01). Risk factors for delayed motor performance were: neonatal convulsions (odds ratio [OR] 4.5; 95% confidence interval [CI] 1.6–12.9), low maternal educational level (OR 3.3; 95% CI 1.7–6.5), male sex (OR 2.8; 95% CI 1.8–4.3), and chronic lung disease (OR 2.1; 95% CI 1.1– 4.1). We conclude that preterm infants are at high risk of delayed motor performance and non‐optimal test‐taking behaviour.

QUANTITATIVE MUSCLE ULTRASONOGRAPHY IN THE FOLLOW-UP OF JUVENILE DERMATOMYOSITIS

Introduction: We explored the use of quantitative muscle ultrasonography (QMUS) for follow‐up of juvenile dermatomyositis (JDM). Methods: Seven JDM patients were evaluated at diagnosis and 1, 3, 6, 12, and 24 months using the Childhood Myositis Assessment Scale (CMAS) and QMUS. Muscle thickness (MT) and quantitative muscle echo intensity (EI) were assessed with QMUS in 4 muscles. Results: Six patients experienced a monocyclic course. At diagnosis EI was slightly increased, and MT was relatively normal. After start of treatment MT first decreased and EI increased, with normalization of EI within 6–12 months (n = 4). One patient had higher EIs at diagnosis and slower normalization, indicating fibrosis, despite early normalization of CMAS. One patient experienced a chronic course, with high EIs and atrophy during follow‐up. Conclusions: QMUS can provide additional information for follow‐up of JDM regarding disease severity and residual muscle damage, particularly after normalization of CMAS. Muscle Nerve 52: 540–546, 2015

The early postnatal nutritional intake of preterm infants affected neurodevelopmental outcomes differently in boys and girls at 24 months

This study assessed whether increased amino acid and energy intake in preterm infants during the first week of life was associated with improved neurodevelopment at the corrected age (CA) of 24 months.

Perceived Motor Competence Differs From Actual Performance in 8-Year-Old Neonatal ECMO Survivors

OBJECTIVE: To assess perceived motor competence, social competence, self-worth, health-related quality of life, and actual motor performancein 8-year-old survivors of neonatal extracorporeal membrane oxygenation (ECMO). METHODS: In a prospective nationwide study, 135 children completed the extended version of the “athletic competence” domain of the Self Perception Profile for Children (SPPC) called the m-CBSK (Motor supplement of the Competentie BelevingsSchaal voor Kinderen) to assess perceived motor competence, the SPPC, and the Pediatric Quality of Life Inventory (PedsQL), andwere tested with the Movement Assessment Battery for Children. SD scores (SDS) were used to compare with the norm. RESULTS: The mean (SD) SDS for perceived motor competence, social competence, and self-worth were all significantly higher than the norm: 0.18 (0.94), P = .03; 0.35 (1.03), P < .001; and 0.32 (1.08), P < .001, respectively. The total PedsQL score was significantly below the norm: mean (SD) SDS: –1.26 (1.53), P < .001. Twenty-two percent of children had actual motor problems. The SDS m-CBSK and actual motor performance did not correlate (r = 0.12; P = .17). The SDS m-CBSK significantly correlated with the athletic competence domain of the SPPC (r = 0.63; P < .001). CONCLUSIONS: Eight-year-old ECMO survivors feel satisfied with their motor- and social competence, despite impaired PedsQL scores and motor problems. Because motor problems in ECMO survivorsdeteriorate throughout childhood, clinicians should be aware that these patients may tend to “overrate” their actual motor performance. Education andstrict monitoring of actual motor performanceare important to enable timelyintervention.

Domains of Daily Physical Activity in Children with Mitochondrial Disease: A 3D Accelerometry Approach

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.

Outcome measures for children with mitochondrial disease: consensus recommendations for future studies from a Delphi-based international workshop

Although there are no effective disease-modifying therapies for mitochondrial diseases, an increasing number of trials are being conducted in this rare disease group. The use of sensitive and valid endpoints is essential to test the effectiveness of potential treatments. There is no consensus on which outcome measures to use in children with mitochondrial disease. The aims of this two-day Delphi-based workshop were to (i) define the protocol for an international, multi-centre natural history study in children with mitochondrial myopathy and (ii) to select appropriate outcome measures for a validation study in children with mitochondrial encephalopathy. We suggest two sets of outcome measures for a natural history study in children with mitochondrial myopathy and for a proposed validation study in children with mitochondrial encephalopathy.

Implicit and explicit motor sequence learning in children born very preterm

BACKGROUND Motor skills can be learned explicitly (dependent on working memory (WM)) or implicitly (relatively independent of WM). Children born very preterm (VPT) often have working memory deficits. Explicit learning may be compromised in these children. AIMS This study investigated implicit and explicit motor learning and the role of working memory in VPT children and controls. METHODS Three groups (6-9 years) participated: 20 VPT children with motor problems, 20 VPT children without motor problems, and 20 controls. A nine button sequence was learned implicitly (pressing the lighted button as quickly as possible) and explicitly (discovering the sequence via trial-and-error). RESULTS Children learned implicitly and explicitly, evidenced by decreased movement duration of the sequence over time. In the explicit condition, children also reduced the number of errors over time. Controls made more errors than VPT children without motor problems. Visual WM had positive effects on both explicit and implicit performance. CONCLUSION VPT birth and low motor proficiency did not negatively affect implicit or explicit learning. Visual WM was positively related to both implicit and explicit performance, but did not influence learning curves. These findings question the theoretical difference between implicit and explicit learning and the proposed role of visual WM therein.