Cognitive, motor, behavioural and academic performances of children born preterm: a meta-analysis and systematic review involving 64 061 children.

BACKGROUND: Preterm birth may leave the brain vulnerable to dysfunction. Knowledge of future neurodevelopmental delay in children born with various degrees of prematurity is needed to inform practice and policy. OBJECTIVE: To quantify the long-term cognitive, motor, behavioural and academic performance of children born with different degrees of prematurity compared with term-born children. SEARCH STRATEGY: PubMed and Embase were searched from January 1980 to December 2016 without language restrictions. SELECTION CRITERIA: Observational studies that reported neurodevelopmental outcomes from 2 years of age in children born preterm compared with a term-born cohort. DATA COLLECTION AND ANALYSIS: We pooled individual estimates of standardised mean differences (SMD) and odds ratios (OR) with 95% confidence intervals using a random effects model. MAIN RESULTS: We included 74 studies (64 061 children). Preterm children had lower cognitive scores for FSIQ (SMD: -0.70; 95% CI: -0.73 to -0.66), PIQ (SMD: -0.67; 95% CI: -0.73 to -0.60) and VIQ (SMD: -0.53; 95% CI: -0.60 to -0.47). Lower scores for preterm children in motor skills, behaviour, reading, mathematics and spelling were observed at primary school age, and this persisted to secondary school age, except for mathematics. Gestational age at birth accounted for 38-48% of the observed IQ variance. ADHD was diagnosed twice as often in preterm children (OR: 1.6; 95% CI: 1.3-1.8), with a differential effect observed according to the severity of prematurity (I2 = 49.4%, P = 0.03). CONCLUSIONS: Prematurity of any degree affects the cognitive performance of children born preterm. The poor neurodevelopment persists at various ages of follow up. Parents, educators, healthcare professionals and policy makers need to take into account the additional academic, emotional and behavioural needs of these children. TWEETABLE ABSTRACT: Adverse effect of preterm birth on a child's neurodevelopment persists up to adulthood.

Cortical vision, MRI and developmental outcome in preterm infants.

OBJECTIVES: To test two measures of visual cortical function in the first year of life as early markers of functionally significant brain damage in infants born preterm: orientation-reversal visual event-related potentials (OR-VERP) and a behavioural test of cortically controlled visual attention-fixation shifts under competition (FS). Also to examine how these measures relate to (1) perinatal brain insults identified by MRI, and (2) later neurodevelopmental status. PATIENTS AND METHODS: After neonatal and term-age-equivalent MRI, 26 preterm infants (<32 weeks of gestational age, mean 28.1 weeks) were given the OR-VERP and FS tests before 12 months post-term age and a neurodevelopmental assessment (Griffiths Scales) at 2 years. MRI scans examined for parenchymal lesions, intraventricular haemorrhage, ventricular dilatation and diffuse excessive high signal intensity were classified into three categories of severity. Cortical visual test results were compared across these categories and examined as predictors of developmental status at 2 years. RESULTS: 26 infants were studied. 13/25 infants showed significant OR-VERP responses. 12/26 showed normal FS performance. On both tests, the proportion of infants meeting these criteria decreased significantly with MRI severity. As predictors of Griffiths developmental quotient < or =80, the FS test had a sensitivity of 100%, a specificity of 61%, and positive and negative predictive values of 50% and 100%, respectively; corresponding values for OR-VERP were 86%, 65%, 50% and 92% . CONCLUSIONS: Visual cortical tests can provide early indicators of the functional impact of perinatal brain damage in the preterm infant.

Effect of eccentric exercise on patients with chronic exertional compartment syndrome.

There are a number of similarities between chronic exertional compartment syndrome (CECS) and the effects of high force eccentric contractions in healthy controls. We hypothesised that CECS patients would be particularly susceptible to pain, fatigue and swelling after eccentric exercise. Ten CECS patients [aged 30.3 (8.0) years, mean (SD)], 7 males) and 14 healthy controls [aged 32.3 (9.0) years, 7 males] performed 40 maximal eccentric contractions of the anterior tibial muscles at an angular velocity of 90(o) s(-1). Maximal voluntary isometric contractions (MVC), force generated by electrical stimulation at 10 Hz and 50 Hz and muscle thickness (measured by real-time ultrasound scanning) were measured before exercise and for 10 min afterwards. Ratings of pain and tenderness were made before exercise, then 24 h and 48 h later. The two groups were comparable for initial isometric strength and muscle size. MVC force immediately after exercise fell to 90 (2.5)% [mean (SEM)] in patients and 86.5 (2.4)% in controls (P<0.0005 for both groups) and had not recovered after 10 min. Preferential loss of force at the low stimulation frequency occurred in both groups to a similar extent (20%, P<0.0005) and continued to decline over 10 min of recovery. There was no significant change in muscle thickness in either group. Only mild pain and tenderness were reported by the controls. The patients showed great individual variation but their mean pain scores were significantly higher during dorsiflexion and palpation (P<0.05) 24 h after exercise. After 48 h the patients reported more pain during dorsiflexion (P=0.005), plantarflexion (P<0.05) and palpation (P<0.05). These results suggest that some, but not all, CECS patients may be more susceptible to the pain associated with eccentric contractions that is thought to be the cause of damage and inflammation of connective tissue.

Electromyographic and kinematic indicators of fatigue in horses: a pilot study.

Muscle fatigue can be quantified using Fourier analysis of the recorded EMG signal. Median frequency is the frequency at which the Fourier profile is bisected, and this measure typically shifts to smaller values during fatigue. This technique was combined with kinematic analysis to describe the time course of fatigue in horses galloping on an inclined treadmill. It was hypothesised that EMG median frequency would decrease in tandem with changes in kinematic variables through the exercise test. Three fit Thoroughbred horses had retroreflective markers placed on their hooves and withers. Surface electrodes were attached to the skin over the forelimb deltoid muscle. After warm-up at walk and trot, each horse galloped at 110% VO2max on a treadmill inclined to 7.5% until fatigue onset. Kinematic data were recorded at 200 Hz for 5 s at 30 s intervals, and raw EMG data were recorded at 1024 Hz for 3 s at 15 s intervals. Fatigue onset was the point in time when the horse could not keep up with the treadmill speed with minimal encouragement. One horse performed the entire exercise test on the same lead, while the other 2 horses changed leads periodically, interrupting the changes in both the EMG and kinematic measurements. Overall, through the course of the trials, mean stride length increased by 0.34 m and stride duration increased by 0.03 s. Vertical excursion of the trunk marker increased by 0.03 m. For the horse that did not change lead, median frequency of the EMG signal decreased by 36%. In the other 2 horses, lead changes were interspersed between smaller decreases in median frequency, whereupon median frequency recovered to starting levels immediately following a lead change. The median frequency decreased by 12-20% between lead changes. Kinematic changes are more global indicators of fatigue, while the EMG indicators are dependent upon lead changes.