Assessment of Prevalence of Persons with Down Syndrome: A Theory-based Demographic Model

Destination unknown: Parents and healthcare professionals' perspectives on transition from paediatric to adult care in Down syndrome

BACKGROUND

Transitioning from paediatric medical care to adult care is a challenging process for children, parents and healthcare professionals. The aim of this study was to explore the experiences, concerns and needs of parents of children with Down syndrome and of professionals regarding this transition.

METHOD

A qualitative study was performed using semi-structured interviews with 20 parents of children with Down syndrome and six healthcare professionals.

RESULTS

We showed that parents and professionals have concerns during each of the three distinct phases of transition (preparation, transfer and integration). Data disclose specific concerns regarding communication, continuity of care and rebuilding trust. We propose a framework for the transition to adult care.

CONCLUSIONS

The transition in medical care for children with Down syndrome should be flexible, patient-centred and coordinated together with patients and parents. Only in ensuring continuity of care will individuals with Down syndrome not get lost in transition.

Epidemiology of Male Hypogonadism

The epidemiology of male hypogonadism has been understudied. Of the known causes of endogenous androgen deficiency, only Klinefelter syndrome is common with a likely population prevalence of greater than 5:10,000 men (possibly as high as 10-25:10,000). Mild traumatic injury might also be a common cause of androgen deficiency (prevalence 5-10:10,000 men), but large, long-term studies must be completed to confirm this prevalence estimation that might be too high. The classic causes of male androgen deficiency-hyperprolactinemia, pituitary macroadenoma, endogenous Cushing syndrome, and iron overload syndrome-are rare (prevalence < 10,000 men).

Estimation of the number of people with Down syndrome in Europe

We aimed to estimate the nonselective live birth prevalence, actual live birth prevalence, reduction percentage because of selective terminations, and population prevalence for Down syndrome (DS) in European countries. The number of people with DS alive in a country was estimated by first modeling the number of live births of children with DS by year of birth. Subsequently, for these different years of birth, survival curves for people with DS were constructed and then applied to these yearly estimates of live births with DS. For Europe, 2011-2015, we estimate 8,031 annual live births of children with DS, which would have been around 17,331 births annually, absent selective terminations. The estimated reduction of live birth prevalence was, on average, 54%, varying between 0% in Malta and 83% in Spain. As of 2015, we estimate 417,000 people with DS are living in Europe; without elective terminations, there would have been about 572,000 people with DS, which corresponds to a population reduction rate of 27%. Such statistics can be important barometers for prenatal testing trends and resource allocation within countries. Disability awareness initiatives and public policy initiatives can also be better grounded with these more precise estimates.

Systematic Review of Instrumented Measures of Skeletal Muscle Mechanical Properties: Evidence for the Application of Shear Wave Elastography with Children

The aim of this review was to identify instrumented devices that quantify skeletal muscle mechanical properties and to evaluate their potential clinical utility and clinimetric evidence with respect to children. Four databases were searched to identify articles reporting original clinimetric data for devices measuring muscle stiffness or elastic modulus, along a muscle's main fibre direction. Clinimetric evidence was rated using the Consensus-Based Standard for the Selection of Measurement Instruments (COSMIN) checklist. Sixty-five articles provided clinimetric data for two devices meeting our criteria: the Aixplorer and the Acuson. Both are shear wave elastography devices that determine the shear modulus of muscle tissue. The Aixplorer had strong construct validity and reliability, and the Acuson, moderate construct validity and reliability. Both devices have sound clinical utility with non-invasive application at various joint positions and data acquisition in real time, minimizing fatigue. Further research is warranted to evaluate utility for children with specific disorders of abnormal muscle structure or function.

Intra-Day and Inter-Day Reliability of Measurements of the electromyographic signal on masseter and temporal muscles in patients with Down syndrome

The aim of the present study was to evaluate intra-day (test) and inter-day (re-test) reliability of surface electromyography (sEMG) signals of the masseter and temporal muscles in patients with Down syndrome (DS). We determined the reliability of sEMG variables in 33 patients with DS. EMG signals were recorded at rest as well as during maximum voluntary clenching and maximum habitual intercuspation (MHI). The signals were analyzed considering the amplitude in the root mean square (RMS), mean frequency (MNF), median frequency (MDF) and approximate entropy (ApEn). The intraclass correlation (ICC_2,1) for the three trials recorded during MHI in the two sessions (test and retest) revealed excellent intra-session and inter-session reliability (ICC_2,1 = 0.76 to 0.97) for all sEMG variables and muscles. In the rest position, excellent reliability was found for RMS and ApEn (ICC_2,1 = 0.75 to 1.00) and good to excellent reliability was found for MDF and MNF (ICC_2,1 = 0.64 to 0.93). The intra-session (test) and inter-session (re-test) analyses demonstrated the reliability of nonlinear sEMG variables of the masticatory muscles in adults with Down Syndrome.

Mortality Among Children with Down syndrome in Hong Kong: A Population-Based Cohort Study from Birth

OBJECTIVES

To describe the mortality patterns, comorbidities, and attendance at accident and emergency departments among children with Down syndrome in Hong Kong.

STUDY DESIGN

This is a population-based, retrospective cohort study of live births of children with Down syndrome delivered between 1995 and 2014, as identified from territory-wide hospitalization data in Hong Kong. The Kaplan-Meier product limit method was adopted to estimate the survival probabilities of children with Down syndrome by selected demographic and clinical characteristics. Cox regression analyses were conducted to examine associations of comorbidities and accident and emergency department accident and emergency departments attendances with mortality patterns.

RESULTS

There were 1010 live births of children with Down syndrome in Hong Kong within the study period and the average rate of live births with Down syndrome was 8.0 per 10 000 live births (95% CI, 6.8-9.30). The rate of live births with Down syndrome over the past 2 decades decreased from 11.8 per 10 000 live births in 1995 to 3.4 per 10 000 in 2014. Eighty-three patients with Down syndrome died during this period. The overall 6-month and 1- and 5-year survival probabilities were 95.8%, 94.4%, and 92.6%, respectively. There was a significant decrease in mortality rates over the study period, particularly among those born between 2000-2004 and 2005-2009 compared with those born between 1995 and 1999 (P < .05). Patients with Down syndrome without congenital cardiovascular anomalies and without low birth weight had lower mortality rates than those with these diagnoses.

CONCLUSIONS

Over the past 2 decades, the early life mortality of children with Down syndrome in Hong Kong has improved significantly along with a reduction in Down syndrome live births.

Plasma neurofilament light chain: A potential prognostic biomarker of dementia in adult Down syndrome patients

People with Down syndrome (DS) are at high risk of developing Alzheimer disease (AD) with aging. The diagnosis and treatment trials are hampered by a lack of reliable blood biomarkers. Plasma neurofilament light chain (NfL) is one of the established biomarkers of AD, suggesting that it may be useful as an indicator of dementia in DS patients. The aims of this study were: 1) to examine whether plasma levels of NfL in DS patients are correlated with decreased adaptive behavior scores one year after sample collection, and 2) to compare plasma levels of NfL in adults with DS and an age-matched healthy control population. In this study, plasma levels of NfL in 24 patients with DS and 24 control participants were measured by the single-molecule immunoarray (Simoa) method. We observed significantly increased plasma NfL levels in the DS compared with the control group. There was a significant correlation between age and levels of plasma NfL in both groups. This age-dependent elevation was steeper in the DS compared with the control group. Moreover, elevated plasma NfL was associated with decreased adaptive behavior scores one year later, after age-adjustment. Previously reported blood-based biomarkers available in Simoa for DS, plasma total tau and phosphorylated tau, were not significantly correlated with the annual decrement of adaptive behavior scores after age-adjustment. These results suggest that plasma NfL has the potential to serve as an objective biomarker to predict dementia in adult DS patients.

Trisomy 21 screening based on first and second trimester in a Taiwanese population

OBJECTIVE

This study investigates the performance of first- and second-trimester screening tests for detecting fetal trisomy 21 in a Taiwanese population.

MATERIALS AND METHODS

This multicenter study 29,137 cases enrolled the chromosomal abnormality screening between 2013 and 2014 two years period from Taipei city. There were 23,990 was done the first trimester screening using a combination of fetal nuchal translucency, maternal serum β-human chorionic gonadotropin, and pregnancy-associated plasma protein-A between 11⁺⁰ and 13⁺⁶ weeks of gestation age. Second-trimester screening was done for 5149 cases using a double test (β-human chorionic gonadotropin and serum alpha fetoprotein) between 15 and 20 weeks of gestation. The cut-off risk for both is 1:270 or higher.

RESULTS

This multicenter study 29,137 cases that completed first- and second-trimester screening, and the outcome was available in 28,726 cases. The mean maternal age of the screen-positive group was 34.6 ± 4.2 years. The first-trimester had 891 cases screening positive with a detection rate of 97.5% for fetal trisomy 21, and false positive rate of 3.5%. In the second-trimester had 334 cases screening positive, the detection rate and false positive rate were 33.3% and 6.4% for trisomy 21, respectively.

CONCLUSION

The first-trimester screening had higher performance with a lower false positive rate than the second-trimester screening. First-trimester screening could reduce the rate of unnecessary invasive testing for all pregnant women.

Muscle tone assessments for children aged 0 to 12 years: a systematic review

AIM

The aim of this study was to identify and examine the psychometric properties of muscle tone assessments for children aged 0 to 12 years.

METHOD

Four electronic databases were searched to identify studies that included assessments of resting and/or active muscle tone. Methodological quality and overall psychometric evidence of studies were rated using the COnsensus-based Standards for the selection of health Measurement INstruments checklist.

RESULTS

Twenty-one assessments were identified from 97 included studies. All assessments were broad developmental assessments that included muscle tone items or subscales. Most assessments (16/21) were designed for young children (<2y). Four assessments measured resting and active tone and demonstrated at least moderate validity or reliability: the Amiel-Tison Neurological Assessment (ATNA) at term, Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS), Premie-Neuro for newborn infants, and the Hammersmith Infant Neurological Examination (HINE) for infants aged 2 months to 2 years. For children over 2 years, the Neurological Sensory Motor Developmental Assessment (NSMDA) assesses resting and active tone but has limited validity.

INTERPRETATION

The ATNA at term, NNNS, Premie-Neuro, HINE, and NSMDA can assess resting and active tone in infants and/or children. Further psychometric research is required to extend reliability, validity, and responsiveness data, particularly for older children.

WHAT THIS PAPER ADDS

This is the first review of muscle tone assessments for children aged 0 to 12 years. Twenty-one assessments contain muscle tone items and 16 are for children under 2 years. Four assessments are reliable or valid to measure both resting and active tone.

Aging With Down Syndrome: The Dual Diagnosis: Alzheimer's Disease and Down Syndrome

BACKGROUND

People with Down syndrome (DS) enjoy a longer life expectancy now than they ever have before and are therefore at greater risk of developing conditions associated with aging, including dementia.

OBJECTIVES

To explore the phenomenon of dementia in DS.

METHODS

Medline and Google Scholar searches were conducted for relevant articles, chapters, and books published until 2017. Search terms included Alzheimer's disease, cognitive impairment, dementia, DS, and trisomy 21. Publications found through this indexed search were reviewed for further references.

RESULTS AND CONCLUSIONS

Virtually, all subject aged 35 to 40 show key neuropathologic changes characteristic of Alzheimer's disease, but only a part of them show clinical signs of dementia, usually around the age of 50 years. Early signs of dementia in people with DS may be different from those experienced by the general population. Failure to recognize this can delay diagnosis and subsequent interventions.

Older mothers and increased impact of prenatal screening: stable livebirth prevalence of trisomy 21 in the Netherlands for the period 2000-2013

In the Netherlands, there is no registry system regarding the livebirth prevalence of trisomy 21 (T21). In 2007, a national screening programme was introduced for all pregnant women, which may have changed the livebirth prevalence of T21. The aim of this study is to analyse trends in factors that influence livebirth prevalence of T21 and to estimate the livebirth prevalence of T21 for the period of 2000–2013. National data sets were used on the following: (1) livebirths according to maternal age and (2) prenatal testing and termination of pregnancy (ToP) following diagnosis of T21. These data are combined in a model that uses maternal age-specific risk on T21 and correction factors for natural foetal loss to assess livebirth prevalence of T21. The proportion of mothers aged ≥ 36 years has increased from 12.2% in 2000 to 16.6% in 2009, to gradually decrease afterwards to 15.2% in 2013. The number of invasive tests performed adjusted for total livebirths decreased (5.9% in 2000 vs. 3.2% in 2013) with 0.18% a year (95% CI: −0.21 to −0.15; p   < 0.001). Following invasive testing, a higher proportion of foetuses was diagnosed with T21 (1.6% in 2000 vs. 4.8% in 2013) with a significant increase of 0.22% a year (95% CI: 0.18–0.26; p < 0.001). The proportion of ToP subsequent to T21 diagnosis was on average 85.7%, with no clear time trend. This resulted in a stable T21 livebirth prevalence of 13.6 per 10,000 livebirths (regression coefficient −0.025 (95% CI: −0.126 to 0.77; p = 0.60).

Nonalcoholic Fatty Liver Disease in Italian Children with Down Syndrome: Prevalence and Correlation with Obesity-Related Features

OBJECTIVE

To assess the prevalence of overweight/obesity in a cohort of Italian children with Down syndrome (DS) and to investigate the correlation of both obesity and DS with nonalcoholic fatty liver disease (NAFLD).

STUDY DESIGN

We enrolled 280 children with DS (age range 5-18 years), who were referred to the DS outpatient clinic of the Bambino Gesù Children's Hospital in Rome. For all children, we collected the clinical history and measured anthropometric variables. Eighty-four of 280 children with DS were selected to undergo liver ultrasound scanning to evaluate the presence of NAFLD.

RESULTS

Italian children with DS exhibited a prevalence of 19.64% for overweight and 12.14% for obesity. The prevalence of NAFLD in nonobese (45%) and overweight/obese (82%) children with DS is greater than in the European pediatric nonobese (5.7%) or obese population (33%). Moreover, the severity of liver brightness on ultrasound scan correlated positively with body mass index, triglycerides, low-density lipoprotein-cholesterol, and leptin levels and negatively with adiponectin.

CONCLUSIONS

We demonstrated that, independently from the obese phenotype, children with DS display a greater risk to develop NAFLD than the general pediatric population.

Distress and everyday problems in Dutch mothers and fathers of young adolescents with Down syndrome

BACKGROUND

To provide targeted support to parents of children with DS, knowledge of their distress and everyday problems is crucial. For this purpose, psychosocial screening instruments can be a valuable addition to routine clinical practice.

AIMS

To determine differences on a psychosocial screener concerning distress and everyday problems in parents of young adolescents (YAs) with DS versus control parents and in mothers of YAs with DS versus fathers.

METHODS AND PROCEDURES

We compared outcomes of the Distress Thermometer for Parents in 76 mothers and 44 fathers of 11-13-year-olds with DS versus 64 mothers and 52 fathers of age-matched children without DS (comparing mothers and fathers separately). Additionally, we compared mothers and fathers within 34 parent couples of YAs with DS.

OUTCOMES AND RESULTS

Clinical distress was not more frequent than in control parents. Mothers further did not report more everyday problems and only differed from their controls on one problem domain and some problem items. Fathers, however, reported more problems than their controls across most domains and wished to talk to a professional about their situation more frequently. Outcomes in mothers and fathers within parent couples did not differ significantly.

CONCLUSIONS AND IMPLICATIONS

This is one of few studies to report on the use of psychosocial screening instruments in parents of children with DS. Our results suggested that attention for fathers of YAs with DS is required. Psychosocial screening instruments that inquire about specific problems and the wish for referral can play an important role in achieving this.

Wii-based exercise program to improve physical fitness, motor proficiency and functional mobility in adults with Down syndrome

BACKGROUND

People with Down syndrome (DS) usually display reduced physical fitness (aerobic capacity, muscle strength and abnormal body composition), motor proficiency impairments (balance and postural control) and physical functional limitations. Exergames can be an appealing alternative to enhance exercise engagement and compliance, whilst improving physical fitness and motor function. This study aims to analyse the effects of a Wii-based exercise program on physical fitness, functional mobility and motor proficiency of adults with DS.

METHODS

Twenty-seven adults with DS were randomly allocated to an experimental group (Wii; n = 14) or control group (n = 13). Participants in the experimental group completed a 2-month Wii-based exercise program, with three 1-h sessions per week that included training games for aerobic endurance, balance and isometric strength. Participants completed assessments regarding anthropometric measures, physical fitness, functional mobility and motor proficiency.

RESULTS

Mixed ANOVA analysis showed a significant group by time interaction for aerobic endurance, explosive leg power and flexibility. Independent samples t-test for change scores indicated significant between-group differences favouring the experimental group regarding speed of limb movement, trunk strength and functional mobility, as well as a trend towards significance on body weight. Mann-Whitney's U test for change scores demonstrated between-group differences favouring the experimental group for visceral fat as well as running speed and agility. Large within-group effect sizes were observed for explosive leg power (d = 1.691), body weight (d = 1.281), functional mobility (d = 1.218), aerobic endurance (d = 1.020), speed of limb movement (d = 0.867) and flexibility (d = 0.818) in the experimental group.

CONCLUSIONS

Our findings suggest that Wii-based exercise can be an effective tool to improve physical fitness, functional mobility and motor proficiency of adults with DS, including crucial measures such as aerobic capacity and lower limb strength. Exergames using Wii Fit or other equipment can be appealing alternatives for adults with DS to engage in regular physical activity, preventing sedentary behaviour and decreasing the risk to develop cardiovascular diseases.

Growth charts for Brazilian children with Down syndrome: Birth to 20 years of age

BACKGROUND

The growth of youth with Down syndrome (DS) differs from that of youth without DS, and growth charts specific to DS have been developed. However, little is known about the growth of Brazilian youth with DS. The objective of this study was to construct growth charts for Brazilian youth with DS and compare the growth data with the Child Growth Standards of the World Health Organization (WHO) and charts for children with DS from other studies.

METHODS

Mixed longitudinal and cross-sectional data were collected at University of Campinas, 48 specialized centers for people with intellectual disabilities, and two foundations for people with DS between 2012 and 2015. A total of 10,516 growth measurements from birth to 20 years of age were available from 938 youth with DS (53.7% boys) born between 1980 and 2013. The Lambda Mu Sigma method was applied to construct the curves using generalized additive models for location, scale, and shape.

RESULTS

Length/height-for-age, weight-for-age, and head circumference-for-age percentile curves were generated for Brazilian boys and girls from birth to 20 years of age. Differences in growth of Brazilian youth ranged from -0.8 to -3.2 z-scores compared to WHO standards, and -1.9 to +1.3 compared to children with DS in other studies.

CONCLUSIONS

These specific growth charts may guide clinicians and families in monitoring the growth of Brazilian children and adolescents with DS.

Estimates of live birth prevalence of children with Down syndrome in the period 1991-2015 in the Netherlands

BACKGROUND

In Western countries, increasing maternal age has led to more pregnancies with a child with Down syndrome (DS). However, prenatal screening programs, diagnostic testing and termination of pregnancy influence the actual DS live birth (LB) prevalence as well. The aim of this study is to examine these factors in the Netherlands for the period 1991-2015. In our study, we establish a baseline for DS LB prevalence before non-invasive prenatal testing will be made available to all pregnant women in the Netherlands in 2017.

METHODS

Full nationwide data from the Dutch cytogenetic laboratories were used to evaluate the actual DS LB prevalence. In addition, nonselective DS prevalence, which is the DS LB prevalence that would be expected in absence of termination of pregnancies, was estimated on the basis of maternal age distribution in the general population.

RESULTS

Because of an increase in maternal age, nonselective DS prevalence increased from around 15.6 [95% confidence interval (CI) 13.9-17.4] per 10 000 LBs in 1991 (311 children in total) to around 22.6 (95% CI 20.3-24.9) per 10 000 in 2015 (385), the increase levelling off in recent years. Actual LB prevalence rose from around 11.6 (95% CI 10.9-12.2) per 10 000 in 1991 (230 children) to an estimated peak of 15.9 (95% CI 15.6-16.2) per 10 000 in 2002 (322), gradually decreasing since to 11.1 (95% CI 10.8-11.5) per 10 000 in 2015 (190). Reduction of DS LBs resulting from elective terminations had been fairly constant between 1995 and 2002 at around 28% and rose afterwards from 35% in 2003 to around 50% in 2015.

CONCLUSIONS

In spite of expansion of antenatal screening in the Netherlands in the 1990s and early 2000s, actual DS LB prevalence increased during this period. However, after 2002, this trend reversed, probably because of informing all pregnant women about prenatal testing since 2004 and the implementation of a national screening program in 2007.

Body mass index reference charts for individuals with Down syndrome aged 2-18 years

OBJECTIVE

To develop Brazilian growth charts for body mass index (BMI-for-age) for individuals with Down syndrome (DS). The secondary objective was to compare the BMI-for-age with the Centers for Disease Control and Prevention standards (CDC).

METHODS

A retrospective and cross-sectional growth study of 706 youth with DS (56.7% males) was performed in 51 centers in São Paulo state, Brazil. Weight and height were used to calculate the BMI (kg/m²). The LMS method was applied to construct the growth charts. Z-scores were based on the CDC 2000 growth standards.

RESULTS

The BMI-for-age reference charts showed excellent goodness of fit statistics for boys and girls with DS aged 2-18 years. At 2 years of age, the mean BMI Z-scores of boys and girls with DS were lower compared to those of the CDC (Z-score=-0.2). In contrast, children with DS aged 3-18 years had higher mean Z-scores for BMI-for-age when compared to those of the CDC (Z-scores=+0.2 to +1.3).

CONCLUSIONS

The BMI of Brazilian youth with DS differs from those references established by CDC. These are the first Brazilian BMI-for-age charts for individuals with DS and will hopefully guide clinicians and parents in the evaluation and management of the nutritional status in children and adolescents with DS in Brazil.

Overweight and obesity in children and adolescents with Down syndrome-prevalence, determinants, consequences, and interventions: A literature review

BACKGROUND

Children with Down syndrome (DS) are more likely to be overweight or obese than the general population of youth without DS.

AIMS

To review the prevalence of overweight and obesity and their determinants in youth with DS. The health consequences and the effectiveness of interventions were also examined.

METHODS AND PROCEDURES

A search using MEDLINE, Embase, Web of Science, Scopus, CINAHL, PsycINFO, SPORTDiscus, LILACS, and COCHRANE was conducted. From a total of 4280 studies, we included 45 original research articles published between 1988 and 2015.

OUTCOMES AND RESULTS

The combined prevalence of overweight and obesity varied between studies from 23% to 70%. Youth with DS had higher rates of overweight and obesity than youths without DS. Likely determinants of obesity included increased leptin, decreased resting energy expenditure, comorbidities, unfavorable diet, and low physical activity levels. Obesity was positively associated with obstructive sleep apnea, dyslipidemia, hyperinsulinemia, and gait disorder. Interventions for obesity prevention and control were primarily based on exercise-based programs, and were insufficient to achieve weight or fat loss.

CONCLUSIONS AND IMPLICATIONS

Population-based research is needed to identify risk factors and support multi-factorial strategies for reducing overweight and obesity in children and adolescents with DS.

Estimation of the number of people with Down syndrome in the United States

PURPOSE

An accurate accounting of persons with Down syndrome (DS) has remained elusive because no population-based registries exist in the United States. The purpose of this study was to estimate this population size by age, race, and ethnicity.

METHODS

We predicted the number of people with DS in different age groups for different calendar years using estimations of the number of live births of children with DS from 1900 onward and constructing DS-specific mortality rates from previous studies.

RESULTS

We estimate that the number of people with DS living in the United States has grown from 49,923 in 1950 to 206,366 in 2010, which includes 138,019 non-Hispanic whites, 27,141 non-Hispanic blacks, 32,933 Hispanics, 6,747 Asians/Pacific Islanders, and 1,527 American Indians/American Natives. Population prevalence of DS in the United States, as of 2010, was estimated at 6.7 per 10,000 inhabitants (or 1 in 1,499).

CONCLUSION

Until 2008, DS was a rare disease. In more recent decades, the population growth of people with DS has leveled off for non-Hispanic whites as a consequence of elective terminations. Changes in childhood survival have impacted the age distribution of people with DS, with more people in their fourth, fifth, and sixth decades of life.Genet Med 19 4, 439-447.

Population prevalence of Down's syndrome in the United Kingdom

BACKGROUND

Aim was to estimate the age and sex-stratified prevalence of Down's syndrome (DS) in the United Kingdom (UK) general population using a large primary care database.

METHOD

Data source was the Clinical Practice Research Datalink. We divided the number of individuals with a record of DS present on 01/07/2014 by the total number of individuals, and computed Wilson's confidence intervals. Prevalence by age and sex was represented using local linear smoothing plots.

RESULTS

On July 1(st) 2014, 1159 females and 1317 males with DS were present in the data, corresponding to a prevalence of 5.9 per 10 000 (95% CI: 5.5; 6.2) in females and 6.8 (6.5; 7.2) per 10 000 in males. Prevalence of DS was increased in individuals aged 40 to 55 years compared to adjacent age groups.

CONCLUSIONS

A relative peak prevalence of DS at age 40-55 years may be attributed to the combined effects of a rise in life expectancy and the still limited availability of selective abortion.

Estimates of the live births, natural losses, and elective terminations with Down syndrome in the United States

The present and future live birth prevalence of Down syndrome (DS) is of practical importance for planning services and prioritizing research to support people living with the condition. Live birth prevalence is influenced by changes in prenatal screening technologies and policies. To predict the future impact of these changes, a model for estimating the live births of people with DS is required. In this study, we combine diverse and robust datasets with validated estimation techniques to describe the non-selective and live birth prevalence of DS in the United States from 1900-2010. Additionally, for the period 1974-2010, we estimate the impact of DS-related elective pregnancy terminations (following a prenatal diagnosis of DS) on the live births with DS. The live birth prevalence for DS in the most recent years (2006-2010) was estimated at 12.6 per 10,000 (95% CI 12.4-12.8), with around 5,300 births annually. During this period, an estimated 3,100 DS-related elective pregnancy terminations were performed in the U.S. annually. As of 2007, the estimated rates at which live births with DS were reduced as a consequence of DS-related elective pregnancy terminations were 30% (95% CI: 27.3-31.9) for the U.S. as a whole. Our results and our model provide data on the impact of elective pregnancy terminations on live births with DS and may provide a baseline from which future trends for live births with DS can be estimated.

Route knowledge and configural knowledge in typical and atypical development: a comparison of sparse and rich environments

BACKGROUND

Individuals with Down syndrome (DS) and individuals with Williams syndrome (WS) have poor navigation skills, which impact their potential to become independent. Two aspects of navigation were investigated in these groups, using virtual environments (VE): route knowledge (the ability to learn the way from A to B by following a fixed sequence of turns) and configural knowledge (knowledge of the spatial relationships between places within an environment).

METHODS

Typically developing (TD) children aged 5 to 11 years (N = 93), individuals with DS (N = 29) and individuals with WS (N = 20) were presented with a sparse and a rich VE grid maze. Within each maze, participants were asked to learn a route from A to B and a route from A to C before being asked to find a novel shortcut from B to C.

RESULTS

Performance was broadly similar across sparse and rich mazes. The majority of participants were able to learn novel routes, with poorest performance in the DS group, but the ability to find a shortcut, our measure of configural knowledge, was limited for all three groups. That is, 59 % TD participants successfully found a shortcut, compared to 10 % participants with DS and 35 % participants with WS. Differences in the underlying mechanisms associated with route knowledge and configural knowledge and in the developmental trajectories of performance across groups were observed. Only the TD participants walked a shorter distance in the last shortcut trial compared to the first, indicative of increased configural knowledge across trials. The DS group often used an alternative strategy to get from B to C, summing the two taught routes together.

CONCLUSIONS

Our findings demonstrate impaired configural knowledge in DS and in WS, with the strongest deficit in DS. This suggests that these groups rely on a rigid route knowledge based method for navigating and as a result are likely to get lost easily. Route knowledge was also impaired in both DS and WS groups and was related to different underlying processes across all three groups. These are discussed with reference to limitations in attention and/or visuo-spatial processing in the atypical groups.

Relationship between motor skill competency and executive function in children with Down's syndrome

BACKGROUND

Previous studies suggest that children with Down's syndrome (DS), a genetically based neurodevelopmental disorder, demonstrate motor problems and cognitive deficits. The first aim of this study was to examine motor skills and executive functions (EFs) in school-age children with DS. The second aim was to investigate the relationship between these two performance domains.

METHODS

The Test of Gross Motor Development (TGMD-2), the Movement Assessment Battery Children-2 checklist (MABC2-checklist) and the Trail-Making Test for young children (Trails-P) were used to assess motor and cognitive performances of 18 children (11 boys, 7 girls) with DS aged between 7 and 11 years (9.06 ± 0.96) and an age- and sex-matched sample of 18 typically developing (TD) children (11 boys, 7 girls; 8.99 ± 0.93).

RESULTS

Individuals with DS showed the expected difficulties in attentional control, response suppression and distraction, as well as in locomotor and object control skills, as indicated by poorer performance than TD individuals. Motor performance (bottom-up as well as top-down measures) and EF correlated positively, with regard to the group with DS only though. In the most complex task (distraction), the children of the DS group achieving lower locomotor scores showed lower efficacy scores on the Trails-P. Additionally, strong relationships were found for the perspective of teachers on all sections of the MABC2-Checklist and EF.

CONCLUSION

The findings from this study suggest that children with DS are not only impaired in higher-order EF, but showing also deficits in locomotor and object control skills. This study stresses the importance of early interventions facilitating cognitive abilities and motor skills.

Neonatal diagnosis of Down syndrome in The Netherlands: suspicion and communication with parents

OBJECTIVES

To analyse which dysmorphic features are most recognised in newborns with Down syndrome (DS). Furthermore to evaluate the communication techniques used by clinicians to inform parents about the postnatal diagnosis and compare these to current best practice guidelines.

STUDY DESIGN

Prospective study of a birth cohort of newborns with DS born between 1 January 2003 and 31 December 2006 registered by the Dutch Paediatric Surveillance Unit (DPSU).

RESULTS

A total of 586 children with trisomy 21 were analysed. Most recognised dysmorphic features in DS newborns were 'upslanted palpebral fissures' (74.1%; n = 426), 'hypotonia' (73.7%; n = 424) and 'epicanthic folds' (68.5%; n = 394). The majority of parents were informed about the suspected diagnosis on the day of birth (76.5%; n = 390). Hospital deliveries had a significantly earlier suspected diagnosis (mean age 3-4 days) compared with home deliveries (mean age 7 days) (P < 0.05). In 10% (n = 44), paediatricians described dissatisfaction with the first conversation with parents. In 88.9% (n = 499) parents were both present when the diagnosis was told, however the child was not present during the conversation in 51.3% (n = 288). In 10.8% (n = 61) parents were not informed about local parent support groups or community resources.

CONCLUSION

DS is still often diagnosed after birth, usually on the first day of postnatal life. Most identified clinical features were upslanted palpebral fissures, epicanthic folds and hypotonia. Special attention for recognition of all present clinical features is needed for early diagnosis. Appropriate communication with the parents of the message that their child has DS can be difficult. Guidelines can help to make counselling easier and more effective, which in turn may increase parental satisfaction. Not all recommendations for the first conversation with parents were fully implemented in Dutch clinical practice.

A quantitative assessment of educational integration of students with Down syndrome in the Netherlands

BACKGROUND

In the Netherlands, as in many other countries, there are indications of an inclusive school policy for children with Down syndrome. However, there is a lack of studies that evaluate to what extent this policy has actually succeeded in supporting the mainstreaming of these students.

METHOD

For the period 1984-2011, the number of children with Down syndrome entering regular education and the percentage of children still in regular education after 1-7 years were estimated on basis of samples from the database of the Dutch Down Syndrome Foundation. These estimations were combined with historical demographic data on the total number of children with Down syndrome in primary school age. Validity of the model was examined by comparison of the model-based estimations of numbers and percentages in regular education with relevant available empirical data from the Dutch Ministry of Education and from Dutch special schools.

RESULTS

The percentage of all children with Down syndrome in the age range 4-13 in regular primary education has risen from 1% or 2% (at the very most about 20 children) in 1986-1987, to 10% (about 140 children) in 1991-1992, to 25% (about 400) in 1996-1997, to 35% (about 650) in 2001-2002 and to 37% (about 800) since 2005-2006. The proportional increase stopped in recent years.

CONCLUSION

During the 1980s and 1990s, clearly more and more children with Down syndrome were in regular education, being supported by the then existing ad hoc regulations aimed at providing extra support in regular education. In the Netherlands, in 2003, these temporary regulations were transformed into structural legislation for children with disabilities. With regard to the mainstreaming of students with Down syndrome, the 2003 legislation has consolidated the situation. However, as percentages in regular education stayed fairly constant after 2000, it has failed to boost the mainstreaming of children with Down syndrome. The results of this study are discussed in the context of national and international legislation and educational policy.

Health related quality of life in parents of six to eight year old children with Down syndrome

Raising a child with Down syndrome (DS) has been found to be associated with lowered health related quality of life (HRQoL) in the domains cognitive functioning, social functioning, daily activities and vitality. We aimed to explore which socio-demographics, child functioning and psychosocial variables were related to these HRQoL domains in parents of children with DS. Parents of 98 children with DS completed the TNO-AZL adult quality of life questionnaire (TAAQOL) and a questionnaire assessing socio-demographic, child functioning and psychosocial predictors. Using multiple linear regression analyses for each category of predictors, we selected relevant predictors for the final models. The final multiple linear regression models revealed that cognitive functioning was best predicted by the sleep of the child (β=.29, p<.01) and by the parent having given up a hobby (β=-.29, p<.01), social functioning by the quality of the partner relation (β=.34, p<.001), daily activities by the parent having to care for an ill friend or family member (β=-.31, p<.01), and vitality by the parent having enough personal time (β=.32, p<.01). Overall, psychosocial variables rather than socio-demographics or child functioning showed most consistent and powerful relations to the HRQoL domains of cognitive functioning, social functioning, daily activities and vitality. These psychosocial variables mainly related to social support and time pressure. Systematic screening of parents to detect problems timely, and interventions targeting the supportive network and the demands in time are recommended.

Current estimate of Down Syndrome population prevalence in the United States

OBJECTIVE

To calculate a reliable estimate of the population prevalence of Down syndrome in the US.

STUDY DESIGN

The annual number of births of infants with Down syndrome were estimated by applying published birth prevalence rates of Down syndrome by maternal age to US data from the Centers for Disease Control and Prevention for the years for which births by maternal age were available (1940-2008). Death certificate data for persons with Down syndrome were available for the years 1968-2007. We estimated the number of people with Down syndrome on January 1, 2008, using a life table approach based on proportions of deaths by age. Monte Carlo sampling was used to create 90% uncertainty intervals (UIs) for our estimates.

RESULTS

We estimated the January 1, 2008, population prevalence of Down syndrome as approximately 250700 (90% UI, 185900-321700) based on proportions of deaths by age from the most recent 2 years (2006-2007) of death certificate data. This estimate corresponds to a prevalence of 8.27 people with Down syndrome per 10000 population (90% UI, 6.14-10.62).

CONCLUSION

Our estimate of Down syndrome prevalence is roughly 25%-40% lower than estimates based solely on current birth prevalence. The results presented here can be considered a starting point for facilitating policy and services planning for persons with Down syndrome.

The population prevalence of Down's syndrome in England and Wales in 2011

There is uncertainty over the population prevalence of people with Down's syndrome in England and Wales. This study aimed to estimate the population prevalence of Down's syndrome in England and Wales in 2011. A meta-analysis of published survival rates of people with Down's syndrome from 1938 to 2010 was conducted and the results were applied to the estimated numbers of babies born with Down's syndrome since 1938 in England and Wales. An estimated 37 090 people had Down's syndrome in England and Wales in 2011, a population prevalence of 0.66 per 1000 people; 650 under 1, 2673 aged 1-5, 7115 aged 5-18, 12819 aged 19-40, 10 626 aged 41-55 and 3207 aged 56 and older. The average life expectancy for babies with Down's syndrome born in 2011 was 51 years and the median life expectancy was 58 years. This study provides clarity on the number of people with Down's syndrome in England and Wales. Owing to sudden increases in the survival of babies with Down's syndrome in the 1950s there are a large proportion of people with Down's syndrome who are in their 40s. These people have an increased risk of developing dementia in the future and services should be aware of their potential needs.

More academics in regular schools? The effect of regular versus special school placement on academic skills in Dutch primary school students with Down syndrome

BACKGROUND

Studies from the UK have shown that children with Down syndrome acquire more academic skills in regular education. Does this likewise hold true for the Dutch situation, even after the effect of selective placement has been taken into account?

METHOD

In 2006, an extensive questionnaire was sent to 160 parents of (specially and regularly placed) children with Down syndrome (born 1993-2000) in primary education in the Netherlands with a response rate of 76%. Questions were related to the child's school history, academic and non-academic skills, intelligence quotient, parental educational level, the extent to which parents worked on academics with their child at home, and the amount of academic instructional time at school. Academic skills were predicted with the other variables as independents.

RESULTS

For the children in regular schools much more time proved to be spent on academics. Academic performance appeared to be predicted reasonably well on the basis of age, non-academic skills, parental educational level and the extent to which parents worked at home on academics. However, more variance could be predicted when the total amount of years that the child spent in regular education was added, especially regarding reading and to a lesser extent regarding writing and math. In addition, we could prove that this finding could not be accounted for by endogenity.

CONCLUSION

Regularly placed children with Down syndrome learn more academics. However, this is not a straight consequence of inclusive placement and age alone, but is also determined by factors such as cognitive functioning, non-academic skills, parental educational level and the extent to which parents worked at home on academics. Nevertheless, it could be proven that the more advanced academic skills of the regularly placed children are not only due to selective placement. The positive effect of regular school on academics appeared to be most pronounced for reading skills.

Older adults with intellectual disability

PURPOSE OF REVIEW

Improvements in health and social care for people with intellectual disability have led to a dramatic increase in the life expectancy of this population, resulting in a large and growing number of older adults with intellectual disability. They are at risk of age-related mental disorders such as dementia and continue to present with high rates of mental illness.

RECENT FINDINGS

Recent research with older adults with intellectual disability has included physical health issues that may affect mental well being, and biological and clinical features of dementia in people with Down syndrome. Two key clinical trials of memantine and antioxidants for dementia in Down syndrome showed that these treatment options were ineffective in the short term. Other research focussed on environmental and psychosocial issues (including carer issues) and end-of-life care.

SUMMARY

Improved mental well being requires effective management of mental illness and co-morbid physical health problems as well as consideration of environmental and social issues. Biological research has identified potential treatments for age-related decline, which has led to the development of medication trials. Despite disappointing results, two recent medication trials showed that randomized controlled trials are feasible in older people with intellectual disabilities - a group who are often excluded from trials.

Changes in yearly birth prevalence rates of children with Down syndrome in the period 1986-2007 in The Netherlands

BACKGROUND

The Netherlands are lacking reliable national empirical data in relation to the development of birth prevalence of Down syndrome. Our study aims at assessing valid national live birth prevalence rates for the period 1986-2007.

METHOD

On the basis of the annual child/adult ratio of Down syndrome diagnoses in five out of the eight Dutch cytogenetic centres, the national annual figures of the National Cytogenetic Network on total numbers of postnatal Down syndrome diagnoses were transformed into national figures on total numbers of postnatal Down syndrome diagnoses in newborn children only. In combination with the national annual data of the Working Group for Prenatal Diagnostics and Therapeutics on numbers of Down syndrome pregnancies not aborted after diagnosis, national figures on birth prevalence were constructed.

RESULTS

For the period 1986-2007, results based on the data of the cytogenetic centres are almost similar to the theory-based model data of de Graaf et al., with a small discrepancy of approximately 4%. Down syndrome birth prevalence in the Netherlands shows an upward trend from around 11 per 10,000 births in the early 1990s to around 14 per 10,000 births nowadays.

CONCLUSION

In spite of expansion of antenatal screening in the Netherlands, Down syndrome live birth prevalence has risen in the last two decades as a result of rising maternal age. This increase in Down syndrome birth prevalence is in contrast to studies from other European countries.