É previsto que o desenvolvimento global das crianças com síndrome de Down (SD) ocorra com atraso, repercutindo nas habilidades cognitivas, sociais, de autocuidados, motoras e linguísticas. As diferenças significativas no padrão usual de aquisição de linguagem de crianças com SD ainda não foram totalmente dimensionadas. Apesar do extenso corpo de conhecimento sobre a SD e desempenho comunicativo, principalmente no âmbito internacional, há consideráveis lacunas para a compreensão destes processos. A proposição deste estudo foi verificar e analisar o desempenho de vocabulário receptivo e expressivo de crianças com SD e comparar com o desempenho de crianças com desenvolvimento típico (DT) pareados pela idade mental (Stanford-Binet) e sexo. Cumpriram-se os aspectos éticos. Participaram do estudo 20 crianças com SD (grupo experimental - GE), de ambos os sexos, com idade cronológica variando entre 36 e 71 meses e 20 crianças com DT (grupo controle - GC), com idade cronológica variando entre 13 e 44 meses. Foi realizada entrevista com os responsáveis e aplicado o Inventário de Desenvolvimento de Habilidades Comunicativas MacArthur (MacArthur). Os procedimentos de avaliação utilizados foram a Observação do Comportamento Comunicativo (OCC), o Teste de Vocabulário por Imagens Peabody (TVIP), o Teste de Linguagem Infantil ABFW Vocabulário Parte B (ABFW) e o Teste de Screening de Desenvolvimento Denver II (Denver II). O tratamento estatístico foi realizado com utilização de testes paramétricos e não paramétricos. Os resultados apontaram diferença estatisticamente significante entre o desempenho do GE e GC para todos os testes aplicados, exceto para a área pessoal-social e motora grossa do instrumento Denver II e para vocabulário expressivo do MacArthur. Em relação às habilidades receptivas e expressivas, o desempenho em vocabulário receptivo foi melhor do que no vocabulário expressivo para ambos os grupos. Na correlação entre os instrumentos aplicados, não foi encontrada correlação estatisticamente significante para desempenho no MacArthur e TVIP para GC e GE e no Denver II e TVIP apenas para GC. Ao analisar o desempenho de crianças com SD verificou-se alteração quanto ao vocabulário receptivo e expressivo. Ao comparar o desempenho das crianças com SD com crianças com DT, pareadas quanto ao sexo e idade mental, verificou-se que as crianças com SD apresentaram desempenho inferior quanto ao vocabulário receptivo e expressivo, com distinções em seus padrões de respostas. / Is provided that the overall development of children with Down syndrome (DS) occurs with delay, reflecting the cognitive, social, self-care, motor and language skills. Significant differences in the usual pattern of language acquisition of children with DS have yet to be scaled. Despite the extensive body of knowledge about DS and communicative performance, especially at the international level, there are considerable gaps in understanding these processes. The purpose of this study was to check and analyze the performance of receptive and expressive vocabulary of children with DS and compare with the performance of children with typical development (TD) matched for dental age (Stanford-Binet) and sex. Were fulfilled the ethical aspects. Study participants were 20 children with DS (experimental group - EG), of both sexes, with age varying between 36 and 71 months and 20 children with TD (control group - CG), with age varying between 13 and 44 months. Was performed an interview with those responsible and apply to the Inventory of Development Communication Skills MacArthur (MacArthur). The evaluation procedures used were the Communicative Behavior Observation (CBO), the Peabody Picture Vocabulary Test (PPVT), the Child Language ABFW Test - Vocabulary Part B (ABFW) and Development Screening Test Denver II (Denver II). Statistical analysis was conducted using parametric and nonparametric tests. The results showed a statistically significant difference between the performance of GE and GC for all tests, except for the personal-social and gross motor Denver II instrument and expressive vocabulary of MacArthur. With regard to receptive and expressive skills, performance on receptive vocabulary was better than the expressive vocabulary for both groups. In the correlation between the instruments applied, no statistically significant correlation was found for performance on MacArthur and PPVT to CG and EG and the Denver II and PPVT only for GC. Analyzing the performance of children with DS was found to change as receptive and expressive vocabulary. Comparing the performance of DS children with TD children, matched by sex and mental age, it was found that children with DS showed lower performance on the receptive and expressive vocabulary, with distinctions in their response patterns.

Motor deficits are a hallmark of Down syndrome (DS), yet little is known about their exact cause. Despite the rich understanding of the neurobiology of DS, there is still a lack of targetable mechanisms for early intervention aimed at alleviating motor changes in people with DS. Therefore, we utilized a mouse model of DS known as Ts65Dn to characterize for the first time the effects of trisomy 21 on spinal cord (SC) development. A central molecular player in SC patterning and cell-type specification, Oligodendrocyte transcription factor 2 (Olig2), is located on human chromosome 21 (Hsa21) and is triplicated in both people with DS and in Ts65Dn mice. To observe the effects of the supernumerary Olig2, we used immunohistochemistry to visualize the OLIG2-derived cellular populations (i.e., motor neurons (MNs) and oligodendrocytes (OLs)), as well as adjacent and interacting cell populations (i.e., ventral spinal interneurons (INs)). We limited our analyses to two embryonic ages—embryonic days (E) 12.5 and 14.5. Our results indicate that there is no overall change in the numbers of OLs at either E12.5 or E14.5. However, there tend to be more OL-fated cells within the pMN domain, where they originate, and migrating cells tend to be clustered closer to the pMN domain at E12.5. IN populations show some changes in Ts65Dn mice at E12.5, with both total and abventricular PAX6+ cell numbers and abventricular NKX2.2+ cell numbers increased in Ts65Dn embryos compared to euploid mice. However, at E14.5 the number of NKX2.2+ cells is unchanged. No difference in the NKX6.1+ population was seen at either time-point. In contrast, there are significant changes in the MN population at both E12.5 and E14.5. Specifically, at E12.5, the total ISL1+ MN population is significantly increased and shows altered regional distribution in the ventral horn of Ts65Dn SCs. Conversely, the Ts65Dn spinal MN population is normalized to euploid levels at E14.5. Overall, our results suggest that neurogenesis, gliogenesis, and cell-type specification of OLIG2-lineage cells are altered in the developing SC of Ts65Dn mice. Thus, this work identifies a novel target for future therapeutic interventions aimed at ameliorating motor changes in DS.

Previous studies have found that spatial processing in children and adults with Down syndrome is different in comparison to the normal population. Some previous studies have also found that there is a high prevalence of colour vision deficiencies in people with Down syndrome. The aim of the present study was to use an objective test, the transient visual evoked potential (VEP), to assess achromatic and chromatic visual processing in adults with Down syndrome. Achromatic VEPs were recorded in response to black-white stimuli presented in patternreversal mode. Chromatic VEPs were recorded in response to two types of colour pattern, presented in pattern onset-offset mode. The two colour types were intended to preferentially stimulate the two principal chromatic pathways of the visual system, the ???redgreen??? and ???blue-yellow??? colour-opponent pathways. These stimuli are here termed the ???LM??? and ???S-(L+M) stimuli, respectively, reflecting the cone types that input to the pathways they are intended to stimulate. Each subject also completed two subjective colour vision tests, the Colour Vision Test Made Easy (CVTME) and the City University Colour Vision Test (CUT). Morphology of the achromatic and chromatic VEPs was found to differ between the group with Down syndrome and an age-matched control group. The latency of the P100 component of the achromatic VEP was found to be significantly later in the group with Down syndrome compared to the control group (the N75 latency was earlier in the group with Down syndrome, but not significantly so). The group-averaged peak-to-peak amplitude of the achromatic VEP was significantly lower in the group with Down syndrome compared to the control group. The major positive component of the VEP in response to the L-M stimulus was of significantly longer latency compared to that of the control group. The major negative component and the peak-to-peak amplitude of this response were not significantly different between the groups. For the response to S-(L+M) stimuli, the latency of the major negativity was significantly earlier in the group with Down syndrome and the major positivity was later, but not significantly so. Amplitude of this response was significantly higher in adults with Down syndrome compared to the control group. Most subjects in both groups passed both the CVTME and CUT. Our findings indicate that chromatic VEPs are abnormal in Down syndrome, and this may reflect abnormal processing of chromatic stimuli in this population. Alternatively, these abnormalities may arise due to abnormal cortical morphology, which may occur with normal or abnormal processing of chromatic signals. These findings further indicate that abnormality of chromatic VEPs may be expected in Down syndrome, and is not necessarily indicative of pathology or other abnormal function that is unrelated to the syndrome.

Changes in health care and increasing provision of community services have resulted in an increased number of community dwelling older adults with intellectual disabilities (ID), leading to questions about future planning for service delivery. Although selected aspects of functioning have been explored in various research studies, less longitudinal information pertaining to broad aspects of health is available to planners. This longitudinal project was designed over 10 years ago with the primary purpose of exploring individual and systemic issues in the health needs of this challenging population, leading to improved service planning.<p>Cross-sectional and longitudinal health data were collected from 360 adults with intellectual disabilities (ID) recruited from social services agencies from across the province of Saskatchewan. Data collection included caregiver information, chart information and directly administered tests of selected aspects of cognitive functioning. Formal data-collection occurred every second year for a maximum of four test times, and was supplemented by follow-up phone calls.<p>Analysis of study results showed that young, rather than older people without DS had a greater severity of health needs related to their underlying conditions, and more problematic behavioral and mental health issues. The reason for this was likely the increased survival of multiply handicapped young people, and the increasing trend for these people to be maintained in the community rather than in large institutions. This population was more likely to receive psychotropic medications, both for underlying problems such as seizure disorders, but also for difficult behaviors such as aggression.<p>On the other hand, adults with DS had relatively fewer problems in their younger adult years, but had increasing problems as they aged. Most aspects of functioning were decreased in the older compared to the younger cohorts, which was consistent with the longitudinal, individual level data showing yearly declines in most measured skills. These declines were greater than those found in adults without DS. Although yearly declines were noted in most age cohorts, the largest declines were noted in the oldest age groups, 50 years and over, suggesting that, while aging related decline was present from an early age, declines severe enough to suggest a dementing process probably do not start until after middle age. Declines in visual memory appear to precede those in praxis.<p>Mortality was increased with age, lower baseline functioning, DS, male gender, and baseline depressive symptoms.<p>The use of aging programs did not change much during the course of the study, but interesting differences in service use between people with and without DS were noted. Adults with DS were more likely than those without DS to participate in generic aging services, which was thought to be due to people with DS presenting with more typical, Alzheimer type behaviors, rather than severe behaviors such as aggression.

Changes in health care and increasing provision of community services have resulted in an increased number of community dwelling older adults with intellectual disabilities (ID), leading to questions about future planning for service delivery. Although selected aspects of functioning have been explored in various research studies, less longitudinal information pertaining to broad aspects of health is available to planners. This longitudinal project was designed over 10 years ago with the primary purpose of exploring individual and systemic issues in the health needs of this challenging population, leading to improved service planning.<p>Cross-sectional and longitudinal health data were collected from 360 adults with intellectual disabilities (ID) recruited from social services agencies from across the province of Saskatchewan. Data collection included caregiver information, chart information and directly administered tests of selected aspects of cognitive functioning. Formal data-collection occurred every second year for a maximum of four test times, and was supplemented by follow-up phone calls.<p>Analysis of study results showed that young, rather than older people without DS had a greater severity of health needs related to their underlying conditions, and more problematic behavioral and mental health issues. The reason for this was likely the increased survival of multiply handicapped young people, and the increasing trend for these people to be maintained in the community rather than in large institutions. This population was more likely to receive psychotropic medications, both for underlying problems such as seizure disorders, but also for difficult behaviors such as aggression.<p>On the other hand, adults with DS had relatively fewer problems in their younger adult years, but had increasing problems as they aged. Most aspects of functioning were decreased in the older compared to the younger cohorts, which was consistent with the longitudinal, individual level data showing yearly declines in most measured skills. These declines were greater than those found in adults without DS. Although yearly declines were noted in most age cohorts, the largest declines were noted in the oldest age groups, 50 years and over, suggesting that, while aging related decline was present from an early age, declines severe enough to suggest a dementing process probably do not start until after middle age. Declines in visual memory appear to precede those in praxis.<p>Mortality was increased with age, lower baseline functioning, DS, male gender, and baseline depressive symptoms.<p>The use of aging programs did not change much during the course of the study, but interesting differences in service use between people with and without DS were noted. Adults with DS were more likely than those without DS to participate in generic aging services, which was thought to be due to people with DS presenting with more typical, Alzheimer type behaviors, rather than severe behaviors such as aggression.

The purpose of this retrospective case study is twofold: 1) to analyze the current literature regarding speech and language development and intervention in Down syndrome (DS) and 2) to investigate the experiences of a young child with DS in early intervention from birth to age three. More specifically, we are interested in understanding what a diagnosis of DS means for the developing child (clinical description), how the abilities of these children are measured prior to treatment (assessment), which strategies are commonly utilized in therapy for this population (intervention), and expected treatment outcomes for children who receive intervention (progress). By integrating data from all major areas of development, we can provide a holistic description of DS in early childhood and see how DS is manifested in a young child with this diagnosis. Furthermore, this review and case study can guide speech-language pathologists (SLPs) who are interested in evidence-based practice for clients with developmental disabilities. We interviewed the participant’s mother to gain additional perspective on the early intervention process and outcomes. After analyzing early therapeutic and educational records provided by the participant’s mother, we discovered that our participant experienced a similar pattern of speech and language development as her peers with DS; however, at age three, she appeared to be functioning at an above average level relative to expectations for children with DS. We discuss the positive indicators and environmental factors that may have contributed to her success. Our findings support the importance of providing early intervention for children with developmental disabilities. / text

Down’s syndrome is a common chromosomal disorder associated with intellectual disability, congenital anomalies and increased risk of a number of acquired diseases. Despite improvements in life expectancy due to improved medical care, clear health disparities still exist. Down’s syndrome remains an important cause of infant mortality and intellectual disability in Hong Kong and globally. Gaps in existing knowledge include an unknown prevalence of Down’s syndrome, especially amongst adults; unknown patterns of A&E and outpatient utilisation by people with Down’s syndrome; the applicability of international data on hospitalisations of people with Down’s syndrome to Hong Kong; and the current demand on Hong Kong’s public healthcare services by people with Down’s syndrome. This study uses Hospital Authority patient and healthcare episode data to identify people with Down’s syndrome alive in 2010. Data from the Hong Kong Census 2011 is then used to create an estimate of the age- specific point prevalence of Down’s syndrome in Hong Kong on 31/12/2010. The relative risk associated with Down’s syndrome of at least one admission is calculated. Age and gender stratified rates of A&E attendance, outpatient attendance and inpatient admissions for both the Down’s syndrome population and the general population are estimated and compared. Average length of stay is also calculated for both populations and compared. A negative binomial with log link regression model is used to examine the association between patient characteristics, including age, gender, ethnicity and known comorbidities, and admission factors, including admission type, admitting speciality, surgery and intensive care admission, on length of stay. Lastly, the proportion of Hospital Authority A&E attendances, outpatient attendances and inpatient admissions that are by people with Down’s syndrome is calculated. 2,144 people with Down’s syndrome were identified. The overall prevalence of Down’s syndrome on 31/12/2010 in Hong Kong was 3.00 per 10,000. It was highest in those aged under 5 years at 9.95 per 10,000 and decreased with age. Rates of A&E, outpatient attendance and inpatient admission were 2.0, 2.4 and 3.3 times higher respectively in the Down’s syndrome population compared to the general population. The Risk Ratio of at least one admission associated with Down’s syndrome was 2.59 (p<0.001). Factors significantly associated with increased length of stay included infant age group, known thyroid disease, known other circulatory malformation, non-emergency admission, surgery, admission to ICU and 3 or more known comorbidities. Known congenital heart disease and known epilepsy were significantly associated with a shorter length of stay. The overall proportion of A&E attendances, outpatient attendances and inpatient admissions that were by people with Down’s syndrome were 0.06%, 0.07% and 0.10% respectively. This study provides new knowledge on Down’s syndrome in Hong Kong which will be of use to those delivering and planning healthcare services for this population, and also to those providing genetic counselling on Down’s syndrome. At the same time, new questions are raised on morbidity, mortality and equity of healthcare access amongst people with Down’s syndrome. Further research is required to answer these questions and thus allow effective interventions for reducing morbidity and mortality in this population to be designed. / published_or_final_version / Public Health / Master / Master of Public Health

The ability to make purchases in community settings is highly advantageous as it allows individuals freedom of choice and the ability to function within their own community. Independence and autonomy is especially important for individuals with intellectual disabilities (ID’s), however prerequisite knowledge of money concepts required for making cash purchases may be too complex for individuals with cognitive challenges. The use of EFTPOS cards to make purchases is a comparatively easy process with limited prerequisite skills required therefore, is an ideal starting point for teaching purchasing skills to individuals with cognitive challenges. Video modelling (VM) and video self-modelling (VSM) procedures have shown to be effective and efficient instructional techniques for teaching various skills to individuals with ID’s however, research on the effectiveness and efficiency of these procedures with individuals with Down syndrome (DS) or with EFTPOS purchases is minimal. This study aimed to examine the effectiveness of VM and VSM interventions in teaching independent EFTPOS purchasing skills to 6 young adults with DS using a non-concurrent within-participant design. The results indicates that both VM and VSM interventions were effective and efficient as all 6 participants exhibited increases in task acquisition with the introduction of the intervention, and 5 of the 6 were able to consistently use their EFTPOS cards to purchase chosen items throughout intervention and follow-up generalisation probes (2 weeks postintervention). Therefore, this study suggests both VM and VSM may be equally effective for teaching young adults with DS EFTPOS purchasing skills in community stores.

Down syndrome is one of the most common genetic disorders, resulting in a range of neurological and neuromuscular disabilities. Although the presence of specific disabilities varies among individuals with Down syndrome, all individuals with Down syndrome are born with hypotonia (low muscle tone) and over half with congenital heart defects. Later in life, all individuals demonstrate intellectual disabilities to varying degrees, while many also develop early-onset Alzheimer’s disease. While the cause of Down syndrome is known to be a triplication of the 21st chromosome, it is unknown how this extraneous genetic material causes the development of these phenotypes. We have begun research into the biological basis of these disabilities using the tiny nematode, Caenorhabditis elegans as a genetic model. We used the technique RNA interference (RNAi), which allows us to study the in vivo function of genes by knocking down their expression one at a time in a living, behaving animal. We have used this technique to systematically study the in vivo function for genes involved in Down syndrome. To this end, we identified and knocked down C. elegans genes with sequence similarity to 67% of genes on the human 21st chromosome genes. We used these RNAi-treated worms to investigate the neuromuscular function of human chromosome 21 gene equivalents by assaying locomotion and pharyngeal pumping in a blinded screen. We used locomotion as a measure of neurological and neuromuscular function, while we used pharyngeal pumping as a model for cardiac function. We also performed an aldicarb screen to examine the role of some of these genes in the function of the synapse. Our experiments have provided valuable insight into the in vivo function of the vast majority of genes on the human 21st chromosome. This will be vital to identify genes that are potentially involved in eliciting Down syndrome-related phenotypes, laying the groundwork for further studies into the neurobiology of Down Syndrome. / text

published_or_final_version / Paediatrics / Master / Master of Philosophy