The Impact of Preterm Birth on Sleep through Infancy, Childhood and Adolescence and Its Implications.

There is emergent literature on the relationship between the development of sleep-wake cycles, sleep architecture, and sleep duration during the neonatal period on neurodevelopmental outcomes among children born preterm. There is also a growing literature on techniques to assess sleep staging in preterm neonates using either EEG methods or heart and respiration rate. Upon discharge from hospital, sleep in children born preterm has been assessed using parent report, actigraphy, and polysomnography. This review describes the ontogeny and measurement of sleep in the neonatal period, the current evidence on the impact of preterm birth on sleep both in the NICU and in childhood and adolescence, and the interaction between sleep, cognition, and social-emotional outcomes in this population.

Neuropsychological abilities underpinning academic attainment in children born extremely preterm.

Children born extremely preterm (EP) have poorer academic attainment than their term-born peers. There is a need to identify the specific cognitive mechanisms that are associated with poor academic attainment in preterm populations to inform the development of intervention strategies. A parallel mediation analysis was conducted with cross-sectional data from 152 EP children (< 27 weeks of gestation) and 120 term-born controls who were assessed at age 11. Mathematics and reading attainment was assessed using the Wechsler Individual Achievement Test 2nd Edition. Controlling for sex and socio-economic status we evaluated the following mediators: verbal working memory, visuospatial working memory, verbal processing speed, attention, and visuospatial processing. These were assessed using subtests from the standardized NEPSY-II test and Wechsler Intelligence Scale for Children-5th Edition. Verbal working memory, visuospatial working memory, visuospatial processing and verbal processing speed, but not attention, were significant independent mediators between EP birth and attainment in reading. No direct relationship between EP birth and reading attainment remained in the mediated model. All five neuropsychological variables mediated the relationship between EP birth and attainment in mathematics, but a direct effect of EP birth on mathematics remained in the mediated model. Together, all five neuropsychological abilities indirectly explained 44% of the variance in reading and 52% of the variance in mathematics. Visuospatial processing was the strongest mediator of both mathematics and reading. Components of executive function, especially visuospatial processing, are important predictors of academic attainment. Interventions to improve visuospatial skills could be trialed in EP populations.

Growth in extremely preterm children born in England in 1995 and 2006: the EPICure studies.

OBJECTIVES: To determine growth outcomes at 11 years of age in children born <27 weeks of gestation in England in 2006 (EPICure2) and to compare growth from birth to 11 years of age for births<26 weeks with those in England in 1995 (EPICure). METHODS: 200 EPICure2 children assessed at 11 years alongside 143 term-born controls. Growth measures from birth to 11 years were compared for births<26 weeks between EPICure2 (n=112) and EPICure (n=176). Growth parameter z-scores were derived from 1990 UK standards. RESULTS: Among EPICure2 children, mean z-scores for height and weight were close to the population standards (0.08 and 0.18 SD, respectively) but significantly below those of controls: difference in mean (Δ) z-scores for weight -0.42 SD (95% CI -0.68 to -0.17), for height -0.45 SD (-0.70 to -0.20) and for head circumference (HC) -1.05 SD (-1.35 to -0.75); mean body mass index (BMI) z-score in EPICure2 children was 0.18 SD, not significantly different from controls (0.43 SD, p=0.065). Compared with EPICure, EPICure2 children born <26 weeks at 11 years had higher z-scores for weight (Δ 0.72 (0.47, 0.96)), height (Δ 0.55 (0.29, 0.81)) and BMI (Δ 0.56 (0.24, 0.87)), which were not fully explained by perinatal/demographic differences between eras. Weight catch-up was greater from term-age to 2.5/3 years in EPICure2 than in EPICure (1.25 SD vs 0.53 SD; p<0.001). Poor HC growth was observed in EPICure2, unchanged from EPICure. CONCLUSIONS: Since 1995, childhood growth in weight, height and BMI have improved for births <26 weeks of gestation, but there was no improvement in head growth.

Disturbed sleep in children born extremely preterm is associated with behavioural and emotional symptoms.

AIM: To determine whether children born extremely preterm are at increased risk for sleep disturbances and to explore relationships between extremely preterm birth, sleep and attention-deficit/hyperactivity disorder (ADHD) symptoms and emotional symptoms. METHOD: EPICure2 cohort study. Parents of 165 children born ≤26 weeks' gestation (53% male) and 121 children born at term (43% male) completed the Children's Sleep Habits Questionnaire, sleep disordered breathing subscale of the Pediatric Sleep Questionnaire, the emotional problems scale of the Strengths and Difficulties Questionnaire and the ADHD Rating Scale-5 at 11 years of age. RESULTS: Extremely preterm children had greater habitual snoring (adjusted odds ratio 6.8; 95% confidence interval 2.3, 20.3), less frequently fell asleep within 20 minutes (Cohen's d 0.33), higher night wakings (d 0.44) and daytime sleepiness scores (d 0.40) than term-born children; there was no between-group difference in sleep duration scores. Among children without severe disability, night wakings scores partially mediated the relationship between preterm birth and inattention (additional 5% of variance explained), hyperactivity/impulsivity (13%) and emotional problems (9%). Snoring partially mediated the relationship between preterm birth, hyperactivity/impulsivity and inattention (additional 1-5% of variance). CONCLUSION: Children born extremely preterm are at increased risk of disturbed sleep compared to term-born children. As night wakings partially mediated the relationship between preterm birth and ADHD symptoms and emotional problems, reducing sleep disturbance may improve sleep and reduce attention and emotional problems in this population.

No change in neurodevelopment at 11 years after extremely preterm birth.

OBJECTIVE: To determine whether improvements in school age outcomes had occurred between two cohorts of births at 22-25 weeks of gestation to women residents in England in 1995 and 2006. DESIGN: Longitudinal national cohort studies. SETTING: School-based or home-based assessments at 11 years of age. PARTICIPANTS: EPICure2 cohort of births at 22-26 weeks of gestation in England during 2006: a sample of 200 of 1031 survivors were evaluated; outcomes for 112 children born at 22-25 weeks of gestation were compared with those of 176 born in England during 1995 from the EPICure cohort. Classroom controls for each group acted as a reference population. MAIN OUTCOME MEASURES: Standardised measures of cognition and academic attainment were combined with parent report of other impairments to estimate overall neurodevelopmental status. RESULTS: At 11 years in EPICure2, 18% had severe and 20% moderate impairments. Comparing births at 22-25 weeks in EPICure2 (n=112), 26% had severe and 21% moderate impairment compared with 18% and 32%, respectively, in EPICure. After adjustment, the OR of moderate or severe neurodevelopmental impairment in 2006 compared with 1995 was 0.76 (95% CI 0.45 to 1.31, p=0.32). IQ scores were similar in 1995 (mean 82.7, SD 18.4) and 2006 (81.4, SD 19.2), adjusted difference in mean z-scores 0.2 SD (95% CI -0.2 to 0.6), as were attainment test scores. The use of multiple imputation did not alter these findings. CONCLUSION: Improvements in care and survival between 1995 and 2006 are not paralleled by improved cognitive or educational outcomes or a reduced rate of neurodevelopmental impairment.

No Excess of Mathematics Anxiety in Adolescents Born Very Preterm.

OBJECTIVE: To assess whether adolescents born very preterm (VP; <32 weeks' gestation) have an excess of mathematics anxiety compared with their classmates born at term. METHODS: This cohort study included 127 adolescents born VP (51% male, mean age 13.9 years, SD 0.7) and 95 term-born classmates (56% male, mean age 13.7 years, SD 0.7) who completed the Wechsler Individual Achievement Test Second UK Edition and the Mathematics Anxiety Scale-UK at the age of 11 to 15 years. Self-reported trait anxiety was assessed using a composite of 3 items from the Strengths and Difficulties Questionnaire. RESULTS: Adolescents born VP had significantly poorer mathematics attainment than adolescents born at term (difference in means: -0.64 SD; 95% confidence interval -0.95 to -0.34). However, there were no between-group differences in self-reported mathematics anxiety or trait anxiety. There were significant moderate associations between mathematics anxiety and mathematics attainment for adolescents born VP (rho: -0.45) and at term (rho: -0.54), after controlling for trait anxiety. CONCLUSION: Adolescents born VP do not have heightened mathematics anxiety compared with their term-born classmates, despite poorer attainment in mathematics. Improving domain-general cognitive skills and scaffolding learning in the classroom may be more promising avenues for intervention than attempting to reduce mathematics anxiety.

Sleep in children with Smith-Magenis syndrome: a case-control actigraphy study.

STUDY OBJECTIVES: The objectives of the study were (1) to compare both actigraphy and questionnaire-assessed sleep quality and timing in children with Smith-Magenis syndrome (SMS) to a chronologically age-matched typically developing (TD) group and (2) to explore associations between age, nocturnal and diurnal sleep quality, and daytime behavior. METHODS: Seven nights of actigraphy data were collected from 20 children with SMS (mean age 8.70; SD 2.70) and 20 TD children. Daily parent/teacher ratings of behavior and sleepiness were obtained. Mixed linear modeling was used to explore associations between total sleep time and daytime naps and behavior. RESULTS: Sleep in children with SMS was characterized by shorter total sleep time (TST), extended night waking, shorter sleep onset, more daytime naps, and earlier morning waking compared to the TD group. Considerable inter-daily and inter-individual variability in sleep quality was found in the SMS group, so caution in generalizing results is required. An expected inverse association between age and TST was found in the TD group, but no significant association was found for the SMS group. No between-group differences in sleep hygiene practices were identified. A bidirectional negative association between TST and nap duration was found for the SMS group. In the SMS group, increased afternoon sleepiness was associated with increased irritability (p = .007) and overactivity (p = .005). CONCLUSION: These findings evidence poor sleep quality in SMS and the need to implement evidence-based interventions in this population.

Sleep disorders in children with Angelman and Smith-Magenis syndromes: The assessment of potential causes of disrupted settling and night time waking.

BACKGROUND: Sleep problems are common in Smith-Magenis (SMS) and Angelman syndromes (AS). Effectiveness of interventions depends on appropriate assessment, complicated by compromised self-report and health and behaviour difficulties. Studying settling and waking in these syndromes could inform assessment. AIMS: To describe settling and waking behaviours in children at high-risk of sleep and health problems, using direct observation. METHODS AND PROCEDURES: Video and actigraphy data were collected for 12 participants with AS (Mean age = 8.02, SD = 2.81) and 11 with SMS (Mean age = 8.80, SD = 2.18). Settling (30 min prior to sleep onset) and night waking were coded for nineteen behaviours relating to pain, challenging behaviour and caregiver interaction. Lag sequential analyses were conducted for pain-related behaviours. OUTCOMES AND RESULTS: Percentage of time spent in behaviours was calculated. Parent-child interactions (0.00-9.93 %) and challenging behaviours (0 %) were rare at settling and waking in both groups. In the AS group, pain-related behaviours were more likely to occur before waking than by chance (p < 0.001). CONCLUSIONS AND IMPLICATIONS: Findings highlight the importance of considering pain as a cause of sleep problems in AS. The principle and methodology could be extended to individuals with ID experiencing sleep problems.

Multi-Method Assessment of Sleep in Children With Angelman Syndrome: A Case-Controlled Study.

Objectives: To assess sleep quality and timing in children with Angelman syndrome (AS) with sleep problems using questionnaires and actigraphy and contrast sleep parameters to those of typically developing (TD) children matched for age and sex. Methods: Week-long actigraphy assessments were undertaken with children with AS (n = 20) with parent-reported sleep difficulties and compared with age and sex matched TD controls. The presence of severe sleep problems was assessed using the modified Simonds and Parraga sleep questionnaire. Sleep hygiene was measured using the Family Inventory of Sleep Habits. Results: Actigraphy and parent-completed sleep diary data indicated that children with AS had significantly earlier bedtimes (p = .003, Cohen d = .47) and poorer sleep efficiency (78%, p = .04, d = .33) than TD children (84%). No significant differences in total sleep time, sleep onset latency or wake after sleep onset were found between the two groups. The expected relationship between later bedtimes and increasing age found for the TD group (p < .001, ß.78) was not evidenced for the AS group (p = .09, ß.39). Considerable inter-individual and night to night variation in actigraphy assessed total sleep time and wake after sleep onset was found for children with AS compared to TD children. Parent report indicated that a greater proportion of children with AS had severe night waking problems compared to TD children (81 versus 5%). No significant differences in sleep hygiene and excessive daytime sleepiness were found between the two groups (p > .05). Conclusions: This study reports the largest objective dataset of sleep quality parameters in children with AS. Sleep quality in this group was characterised by poor efficiency and significant intra- and inter-individual variability that warrants further investigation. This variability should inform assessment and intervention for sleep in children with AS, as averages of total sleep, even across a 7 day period may not capture the difficulties with night waking highlighted by parental questionnaire report.

Sleep in children with Angelman syndrome: Parental concerns and priorities.

Angelman syndrome is a rare genetic syndrome, in which sleep disturbances are reported for 20-80% of individuals (Williams et al., 2006). This interview study delineated parental perceptions of sleep problems experienced by children with Angelman syndrome and the impact on parental sleep quality, health and wellbeing. The nature of desired interventions was also explored. Semi-structured interviews were completed with parents of 50 children, aged 16 months-15 years with Angelman syndrome who experienced current or historic sleep problems; predominantly night waking and settling problems. Parents were concerned by the impact of their child's sleep quality upon their own ability to function during the day. The importance of considering parental experiences was evidenced by variability in coping e.g. despite the persistence of sleep problems 20% of parents did not feel the need for any additional support. Amongst a range of types of further support desired, 27% cited further support with a behavioural intervention, and information about the trajectory of sleep problems in Angelman syndrome (18%). The results suggest that behavioural interventions supporting both children and parents in improving their sleep quality and well-being, and longitudinal research into sleep problems should be prioritised.