Neurodevelopmental and psychiatric issues in Down's syndrome: assessment and intervention

Transcranial photobiomodulation for neurodevelopmental disorders: a narrative review

BACKGROUND

Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Down syndrome (DS) significantly impact social, communicative, and behavioral functioning. Transcranial photobiomodulation (t-PBM) with near-infrared light is a promising non-invasive neurostimulation technique for neuropsychiatric disorders, including NDDs. This narrative review aimed to examine the preclinical and clinical evidence of photobiomodulation (PBM) in treating NDDs.

METHODS

A comprehensive search across six databases was conducted, using a combination of MeSH terms and title/abstract keywords: "photobiomodulation", "PBM", "neurodevelopmental disorders", "NDD", and others. Studies applying PBM to diagnosed NDD cases or animal models replicating NDDs were included. Protocols, reviews, studies published in languages other than English, and studies not evaluating clinical or cognitive outcomes were excluded.

RESULTS

Nine studies were identified, including one preclinical and eight clinical studies (five on ASD, two on ADHD, and one on DS). The reviewed studies encompassed various t-PBM parameters (wavelengths: 635-905 nm) and targeted primarily frontal cortex areas. t-PBM showed efficacy in improving disruptive behavior, social communication, cognitive rigidity, sleep quality, and attention in ASD; in enhancing attention in ADHD; and in improving motor skills and verbal fluency in DS. Minimal adverse effects were reported. Proposed mechanisms involve enhanced mitochondrial function, modulated oxidative stress, and reduced neuroinflammation.

CONCLUSIONS

t-PBM emerges as a promising intervention for NDDs, with potential therapeutic effects across ASD, ADHD, and DS. These findings underscore the need for further research, including larger-scale, randomized sham-controlled clinical trials with comprehensive biomarker analyses, to optimize treatment parameters and understand the underlying mechanisms associated with the effects of t-PBM.

Cerebral organoids with chromosome 21 trisomy secrete Alzheimer's disease-related soluble aggregates detectable by single-molecule-fluorescence and super-resolution microscopy

Understanding the role of small, soluble aggregates of beta-amyloid (Aβ) and tau in Alzheimer's disease (AD) is of great importance for the rational design of preventative therapies. Here we report a set of methods for the detection, quantification, and characterisation of soluble aggregates in conditioned media of cerebral organoids derived from human iPSCs with trisomy 21, thus containing an extra copy of the amyloid precursor protein (APP) gene. We detected soluble beta-amyloid (Aβ) and tau aggregates secreted by cerebral organoids from both control and the isogenic trisomy 21 (T21) genotype. We developed a novel method to normalise measurements to the number of live neurons within organoid-conditioned media based on glucose consumption. Thus normalised, T21 organoids produced 2.5-fold more Aβ aggregates with a higher proportion of larger (300-2000 nm2) and more fibrillary-shaped aggregates than controls, along with 1.3-fold more soluble phosphorylated tau (pTau) aggregates, increased inflammasome ASC-specks, and a higher level of oxidative stress inducing thioredoxin-interacting protein (TXNIP). Importantly, all this was detectable prior to the appearance of histological amyloid plaques or intraneuronal tau-pathology in organoid slices, demonstrating the feasibility to model the initial pathogenic mechanisms for AD in-vitro using cells from live genetically pre-disposed donors before the onset of clinical disease. Then, using different iPSC clones generated from the same donor at different times in two independent experiments, we tested the reproducibility of findings in organoids. While there were differences in rates of disease progression between the experiments, the disease mechanisms were conserved. Overall, our results show that it is possible to non-invasively follow the development of pathology in organoid models of AD over time, by monitoring changes in the aggregates and proteins in the conditioned media, and open possibilities to study the time-course of the key pathogenic processes taking place.

Minimal invasive prosthetic rehabilitation of a patient with Down syndrome: A case report

INTRODUCTION

Down syndrome (DS), an easily recognized congenital disease, is associated with a high prevalence of dental anomalies. Therefore, special dental care is required.

CASE PRESENTATION

This case report described the minimally invasive prosthetic rehabilitation of a 31-year-old female patient with DS. Prompt diagnosis, consultation with physicians and family, and accurate medical history were needed, and relevant dental, medical, mental, and behavioral factors were considered. A minimally invasive treatment plan was decided after clinical examination, orthopantomography (OPG), and study model analysis. For the upper jaw, an over denture was constructed. For the lower jaw, a simple metal-frame partial denture was made. This treatment plan was decided after considering the difficulty in dentist-patient collaboration and a small maxilla with poor positioning of teeth and negative overbite and over jet.

CONCLUSION

Considering different patient factors including patient cooperation, as well as the medical and dental conditions associated with DS, a minimally invasive prosthodontic treatment option was recommended.

Unraveling Down Syndrome: From Genetic Anomaly to Artificial Intelligence-Enhanced Diagnosis

Down syndrome arises from chromosomal non-disjunction during gametogenesis, resulting in an additional chromosome. This anomaly presents with intellectual impairment, growth limitations, and distinct facial features. Positive correlation exists between maternal age, particularly in advanced cases, and the global annual incidence is over 200,000 cases. Early interventions, including first and second-trimester screenings, have improved DS diagnosis and care. The manifestations of Down syndrome result from complex interactions between genetic factors linked to various health concerns. To explore recent advancements in Down syndrome research, we focus on the integration of artificial intelligence (AI) and machine learning (ML) technologies for improved diagnosis and management. Recent developments leverage AI and ML algorithms to detect subtle Down syndrome indicators across various data sources, including biological markers, facial traits, and medical images. These technologies offer potential enhancements in accuracy, particularly in cases complicated by cognitive impairments. Integration of AI and ML in Down syndrome diagnosis signifies a significant advancement in medical science. These tools hold promise for early detection, personalized treatment, and a deeper comprehension of the complex interplay between genetics and environmental factors. This review provides a comprehensive overview of neurodevelopmental and cognitive profiles, comorbidities, diagnosis, and management within the Down syndrome context. The utilization of AI and ML represents a transformative step toward enhancing early identification and tailored interventions for individuals with Down syndrome, ultimately improving their quality of life.

The association between cardiovascular health and cognition in adults with Down syndrome

INTRODUCTION

Evidence in the general population suggests that predictors of cardiovascular health such as moderate to vigorous physical activity (MVPA), cardiorespiratory fitness, and systolic blood pressure are associated with cognitive function. Studies supporting these associations in adults with Down syndrome (DS) are limited. The purpose of this study was to examine the associations between systolic blood pressure, cardiorespiratory fitness, and MVPA on cognition in adults with DS.

METHODS

This is a cross-sectional analysis using baseline data from a trial in adults with DS. Participants attended a laboratory visit where resting blood pressure, cardiorespiratory fitness (VO2 Peak), and cognitive function (CANTAB® DS Battery) were obtained. The cognitive battery included tests measuring multitasking, episodic memory, and reaction time. Physical activity (accelerometer) was collected over the week following the laboratory visit. Pearson correlations and linear regressions were used to measure the impact of systolic blood pressure, cardiorespiratory fitness, and MVPA on cognitive outcomes.

RESULTS

Complete data was available for 72 adults with DS (26.8 ± 9.3 years of age, 57% female). At baseline, VO2 Peak (21.1 ± 4.2 ml/kg/min) and MVPA were low (14.4 ± 14.4 min/day), and systolic blood pressure was 118.3 ± 13.3 mmHg. VO2 Peak was correlated with simple movement time (rho =  - 0.28, p = 0.03) but was not significant using a linear regression controlling for age and sex. Systolic blood pressure was significantly associated with episodic memory (first attempt memory score: β =  - 0.11, p = 0.002; total errors: β = 0.58, p = 0.001) and reaction time (five-choice movement time: β = 4.11, p = 0.03; simple movement time: β = 6.14, p = 0.005) using age- and sex-adjusted linear regressions. No associations were observed between MVPA and multitasking, episodic memory, or reaction time.

CONCLUSION

Predictors of cardiovascular health, including cardiorespiratory fitness and systolic blood pressure, were associated with some aspects of cognition in adults with DS. While future research should examine the role of improved cardiovascular health on delaying decreases in cognitive function and dementia in adults with DS, we recommend that health care providers convey the importance of exercise and cardiovascular health to their patients with DS.

TRIAL REGISTRATION

NCT04048759, registered on August 7, 2019.

The association of increased body mass index on cardiorespiratory fitness, physical activity, and cognition in adults with down syndrome

BACKGROUND

Obesity is a significant risk factor for Alzheimer's disease; however, this association has not been explored in adults with Down syndrome.

OBJECTIVE

To examine the association of obesity, assessed by body mass index (BMI), with factors related to Alzheimer's disease risk including cardiorespiratory fitness, physical activity, and cognition in adults with Down syndrome.

METHODS

Adults with Down syndrome attended a laboratory visit where BMI, cardiorespiratory fitness (VO2 peak), and cognitive function (CANTAB® DS Battery) were obtained. Physical activity (accelerometer) was collected over the week following the laboratory visit. Wilcoxon rank sum tests were used to evaluate differences in cardiorespiratory fitness, sedentary time, moderate-to-vigorous physical activity (MVPA), and cognition between adults with obesity (BMI≥ 30 kg/m2) and those with healthy weight or overweight (BMI <30 kg/m2). Spearman correlations and linear regressions were used to measure the impact of BMI on cardiorespiratory fitness, MVPA, sedentary time, and cognition.

RESULTS

Data was collected for 79 adults with Down syndrome (26.7 ± 9.0 years of age, 54% female, 54% with obesity). VO2 peak was significantly lower in participants with obesity (18.4 ± 2.5 ml/kg/min) compared to those with healthy weight or overweight (22.9 ± 4.0 ml/kg/min, p < 0.001). BMI was negatively associated with cardiorespiratory fitness (rho = -0.614, p < 0.001). No associations were observed between BMI and physical activity or cognition.

CONCLUSIONS

Lower BMI was associated with improved cardiorespiratory fitness. However, no associations were observed between BMI and cognition or physical activity.

NCT REGISTRATION

NCT04048759.

Sleep and behavioral problems in Down syndrome: differences between school age and adolescence

Background

Individuals with Down syndrome (DS) are at risk of developing sleep problems. In spite of the well-established knowledge on the presence of sleep difficulties in DS individuals and the associated emotional and behavioral problems, less is known about the possible differences in the kind of associations between sleep and emotional/behavioral problems across different age ranges.

Methods

In this retrospective study, we included 289 participants with DS aged 6-18 years with the aims to explore differences in the distribution of sleep problems between specific age groups (school age vs. adolescence) and to identify specific age-based associations between sleep problems and emotional/behavioral problems.

Results

Some differences in the distribution of sleep problems have emerged between age groups. Moreover, differences in the patterns of association between emotional/behavioral difficulties and sleep problems-in particular, sleep-related breathing difficulties and parasomnias-have been observed. However, sleep-wake transition disorders and excessive daily somnolence appear to be related to emotional and behavioral problems (both internalizing and externalizing), in general, across school age and adolescence.

Discussion

These results remark the importance of appropriate neuropsychiatric and psychological evaluation taking into account the age-specific needs and features of individuals with DS.

Talkitt: toward a new instrument based on artificial intelligence for augmentative and alternative communication in children with down syndrome

Introduction

Individuals with Down syndrome (DS) often exhibit a severe speech impairment, with important consequences on language intelligibility. For these cases, the use of Augmentative Alternative Communication instruments, that increase an individual's communication abilities, becomes crucial. Talkitt is a mobile application created by Voiceitt Company, exploiting speech recognition technology and artificial intelligence models to translate in real-time unintelligible sounds into clear words, allowing individuals with language production impairment to verbally communicate in real-time.

Methods

The study evaluated the usability and satisfaction related to the Talkitt application use, as well as effects on adapted behavior and communication, of participants with DS. A final number of 23 individuals with DS, aged 5.54 to 28.9 years, participated in this study and completed 6 months of training. The application was trained to consistently recognize at least 20 different unintelligible words (e.g., nouns and/or short phrases)/person.

Results

Results revealed good usability and high levels of satisfaction related to the application use. Moreover, we registered improvement in linguistic abilities, particularly naming.

Discussion

These results paves the road for a potential role of Talkitt application as a supportive and rehabilitative tool for DS.

The impact of COVID-19 (Coronavirus) on children and young people with Down syndrome in the United Kingdom

The COVID-19 pandemic had a profound impact across the globe. Evidence suggests children with Special Educational Needs and Disabilities and their families experienced impacts on well-being and disruptions in support from education and health services. This study investigated the impact of measures associated with the COVID-19 pandemic on children and young people (CYP) with Down syndrome in the United Kingdom, specifically changes in speech, language and communication abilities, behavior, social, emotional and mental health and access to education and healthcare services. Forty-six parents/carers of CYP with Down Syndrome (aged 2-25 years) completed an online survey between June and September 2020. Parents/carers frequently reported deterioration in speech, language and communication, literacy and attention skills since the onset of the pandemic. Deterioration in social and emotional wellbeing and behavior, including greater reliance on adults were also reported for some CYP with Down syndrome. Parents reported challenges with home-schooling and reductions in support from education and community services. Preferences for support during COVID-19 were for professional support or from other parents. These findings have implications for the support that is now needed for CYP with Down syndrome and their families and for periods of social restrictions in the future.

Anxiety, concerns and emotion regulation in individuals with Williams syndrome and Down syndrome during the COVID-19 outbreak: a global study

Individuals with neurodevelopmental conditions (NDCs) have been reported to experience increased levels of anxiety during the COVID-19 pandemic. In our study, we document how individuals with Down Syndrome (DS; N = 557; Mage = 16.52; 233 female) and Williams syndrome (WS, N = 247; Mage = 18.43; 113 female) experienced the first wave (April 2020-May 2020) of the COVID-19 pandemic across the world. Using multilevel linear mixed regressions, we studied (a) parental reported anxiety of individuals with DS and WS, (b) these individuals' specific concerns, and (c) their use and efficacy of emotion regulation (ER) strategies during the first wave of COVID-19. Predictors of anxiety, such as the age of the individual with NDC, type of condition, and time, were investigated. Individuals with WS experienced higher levels of anxiety compared to those with DS and the older the individuals with NDC were the more anxiety they experienced. In terms of concerns, group effects indicated that individuals with WS scored higher for most of the concerns. There were no gender differences in concerns, yet most of the concerns increased with age except for concerns about loss of routine, boredom, loss of institutional support and family conflict. Finally, significant group effects were found and indicated a more frequent use of a variety of adaptive and maladaptive ER strategies in individuals with WS. We did not identify group differences in the efficacy of ER strategies. Our results indicate that individuals with WS are likely to exhibit higher levels of anxiety, but also higher levels of concerns depending on their age. Similarly, individuals with WS use a variety of ER strategies more frequently but these strategies are not necessarily more efficient for them. We discuss the impact of these findings in relation to anxiety identification and support across individuals with NDCs.

Cognitive impairments in a Down syndrome model with abnormal hippocampal and prefrontal dynamics and cytoarchitecture

The Dp(10)2Yey mouse carries a ∼2.3-Mb intra-chromosomal duplication of mouse chromosome 10 (Mmu10) that has homology to human chromosome 21, making it an essential model for aspects of Down syndrome (DS, trisomy 21). In this study, we investigated neuronal dysfunction in the Dp(10)2Yey mouse and report spatial memory impairment and anxiety-like behavior alongside altered neural activity in the medial prefrontal cortex (mPFC) and hippocampus (HPC). Specifically, Dp(10)2Yey mice showed impaired spatial alternation associated with increased sharp-wave ripple activity in mPFC during a period of memory consolidation, and reduced mobility in a novel environment accompanied by reduced theta-gamma phase-amplitude coupling in HPC. Finally, we found alterations in the number of interneuron subtypes in mPFC and HPC that may contribute to the observed phenotypes and highlight potential approaches to ameliorate the effects of human trisomy 21.

Assessing co-occurring mental health conditions in a multidisciplinary Down syndrome clinic and the role of family history

Compared to the general population, individuals with Down syndrome (DS) are at a significantly increased risk to develop mental health conditions. This study sought to examine individuals with DS and co-existing mental health comorbidities at one DS specialty clinic. Retrospective chart review of medical records including demographics, genetic testing history, personal and familial mental health history, referrals for mental health indications, and recommendations was performed. Summary statistics, logistic regression, and log of odds were converted to odd ratios to assess associations and significance. The charts of 327 patients, average 19.4 years of age (1-70), were reviewed. Nearly half the participants (42.2%) had at least one diagnosis of a mental health condition. Those with a family history were significantly more likely to have a personal diagnosis of a mental health condition than those without a family history (p < 0.01). Moreover, those who completed referrals often received medical management recommendations (86%). This study highlights the prevalence of mental health comorbidities among individuals with DS, and the referral process for mental health conditions, at one DS specialty clinic. Further research is needed to investigate our family history findings, and to determine if these results are generalizable across other DS clinics.

Delusion of Pregnancy in Down Syndrome: Two Case Reports

Individuals with intellectual disability (ID) are more vulnerable to psychotic disorder and schizophrenia than the general population. However, psychotic symptoms have not been widely described in this population. Here, we deeply investigated the cases of two young women with ID and Down syndrome (DS) who developed a delusion of pregnancy, a rare condition defined as a fixed belief of being pregnant despite factual evidence to the contrary. The assessment included psychopathological and neuropsychological examination, as well as the evaluation of cognitive and adaptive functioning. In these cases, delusion manifested as a psychotic symptom of a cyclothymic disorder (case 1) or as an independent delusional disorder (case 2). However, some similarities emerged: both women exhibited good pre-morbid adaptive functioning and family history of psychiatric disorders; moreover, in both cases delusion emerged in association with an external trigger. Difficulties in verbally expressing one's thoughts and beliefs were found, as well as poor abstract reasoning skills that may have affected the ability to deeply conceptualize the delusional idea itself. These findings may provide crucial insights into the clinical manifestation of psychosis in individuals with DS and underscore the importance of a routine psychological and neuropsychological follow-up to provide prompt and adequate intervention.

Cognitive outcome measures for tracking Alzheimer's disease in Down syndrome

Down syndrome (DS) is now viewed as a genetic type of Alzheimer's disease (AD), given the near-universal presence of AD pathology in middle adulthood and the elevated risk for developing clinical AD in DS. As the field of DS prepares for AD clinical intervention trials, there is a strong need to identify cognitive measures that are specific and sensitive to the transition from being cognitively stable to the prodromal (e.g., Mild Cognitive Impairment-Down syndrome) and clinical AD (e.g., Dementia) stages of the disease in DS. It is also important to determine cognitive measures that map onto biomarkers of early AD pathology during the transition from the preclinical to the prodromal stage of the disease, as this transition period is likely to be targeted and tracked in AD clinical trials. The present chapter discusses the current state of research on cognitive measures that could be used to screen/select study participants and as potential outcome measures in future AD clinical trials with adults with DS. In this chapter, we also identify key challenges that need to be overcome and questions that need to be addressed by the DS field as it prepares for AD clinical trials in the coming years.

Impact of the COVID-19 pandemic on daily life, mood, and behavior of adults with Down syndrome

BACKGROUND

The Down syndrome population has been disproportionately affected by Coronavirus 2019 (COVID-19) in terms of experiencing severe illness and death. Societal efforts to curb the spread of COVID-19 may also have taken a heavy toll on the daily lives of individuals with Down syndrome.

OBJECTIVE/HYPOTHESIS

The goal of the study was to understand how the COVID-19 pandemic has altered daily life (including residence, employment, and participation in adult disability day programs) and influenced the mood and behavior of adults with Down syndrome.

METHODS

Between September 2020 and February 2021, caregivers of 171 adults with Down syndrome (aged 22-66 years) located across the United States and in the United Kingdom enrolled in the Alzheimer's Biomarker Research Consortium on Down Syndrome (ABC-DS) completed a survey.

RESULTS

The residence of 17% of individuals was altered, and 89% of those who had been employed stopped working during the pandemic. One-third (33%) of individuals were reported to be more irritable or easily angered, 52% were reported to be more anxious, and 41% were reported to be more sad/depressed/unhappy relative to prepandemic. The majority of changes in mood and behavior were of modest severity.

CONCLUSIONS

The COVID-19 pandemic has had widespread effects on the daily life and mood and behavior of adults with Down syndrome. In the short term, caregivers and providers should be prepared to help adults with Down syndrome with changes in daily routines, residence, employment, or adult disability day programs as society shifts away from COVID-19 safety protocols.

Prevalence of anxiety symptomatology and diagnosis in syndromic intellectual disability: A systematic review and meta-analysis

Individuals with syndromic intellectual disability are at increased risk of experiencing anxiety. Comparing prevalence estimates of anxiety will allow the identification of at-risk groups and inform causal pathways of anxiety. No known study has explored estimates of anxiety symptomatology and diagnosis, including specific anxiety profiles, across groups whilst accounting for methodological quality of studies. This systematic review and meta-analysis aimed to fill this gap. Prior to review completion, methodology and analysis plans were registered and documented in a protocol (CRD42019123561). Data from 83 papers, involving a pooled sample of 13,708 across eight syndromes were synthesised using a random effects model. Anxiety prevalence ranged from 9 % (95 % CI: 4-14) in Down syndrome to 73% in Rett syndrome (95 % CI: 70-77). Anxiety prevalence across syndromic intellectual disability was higher than for intellectual disability of mixed aetiology and general population estimates. Substantial variability between syndromes identified groups at higher risk than others. The identification of high-risk groups is crucial for early intervention, allowing us to refine models of risk and identify divergent profiles.

Modelling the neurodevelopmental pathogenesis in neuropsychiatric disorders. Bioactive kynurenines and their analogues as neuroprotective agents-in celebration of 80th birthday of Professor Peter Riederer

Following introduction of the monoamine oxidase type B inhibitor selegiline for the treatment of Parkinson's disease (PD), discovery of the action mechanism of Alzheimer's disease-modifying agent memantine, the role of iron in PD, and the loss of electron transport chain complex I in PD, and development of the concept of clinical neuroprotection, Peter Riederer launched one of the most challenging research project neurodevelopmental aspects of neuropsychiatric disorders. The neurodevelopmental theory holds that a disruption of normal brain development in utero or during early life underlies the subsequent emergence of neuropsychiatric symptoms during later life. Indeed, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Classification of Diseases, 11th Revision categorize autism spectrum disorder and attention deficit hyperactivity disorder in neurodevelopmental disorders (NDDs). More and more evidence, especially from preclinical studies, is revealing that neurodevelopmental pathology is not limited to the diagnostic class above, but also contributes to the development of other psychiatric disorders such as schizophrenia, bipolar disorder, and obsessive-compulsive disorder as well as neurodegenerative diseases such as PD and Huntington's disease. Preclinical animal research is taking a lead in understanding the pathomechanisms of NDDs, searching for novel targets, and developing new neuroprotective agents against NDDs. This narrative review discusses emerging evidence of the neurodevelopmental etiology of neuropsychiatric disorders, recent advances in modelling neurodevelopmental pathogenesis, potential strategies of clinical neuroprotection using novel kynurenine metabolites and analogues, and future research direction for NDDs.

Parenting Stress in Mothers of Children and Adolescents with Down Syndrome

Parenting stress has deleterious effects on parents, children, and overall family functioning. Parents of children with intellectual disability, including Down Syndrome (DS), show higher levels of parenting stress than parents of typically developing children. This research aimed to (i) evaluate parenting stress levels in a group of mothers of youths with DS using a parent-report questionnaire, (ii) identify children’s individual and clinical features associated with maternal stress, and (iii) identify specific situational life/demographics factors related to maternal stress. Seventy-eight youths with DS underwent a neuropsychological evaluation, whereas mothers completed questionnaires for the assessment of parenting stress and of the child’s emotional and behavioral problems. We found that Parent–Child Difficult Interaction was the domain with the highest percentage of clinical scores (39.7%). Both internalizing and externalizing problems correlated with maternal stress, as well as autistic symptoms. The levels of maternal stress were not associated with any socio-demographic variable. After controlling for child-related correlates of maternal stress and for mothers’ age and education level, unemployed mothers exhibited higher levels of parental distress than employed mothers. The present study highlights that unemployment is related with parenting stress and potentially amenable to policy interventions supporting parents in combining work and family care.

Prevalence of Mental Health Conditions Among 6078 Individuals With Down Syndrome in the United States

Findings from a recent study of the largest documented cohort of individuals with Down syndrome (DS) in the United States described prevalence of common disease conditions and strongly suggested significant disparity in mental health conditions among these individuals as compared with age- and sex-matched individuals without DS. The retrospective, descriptive study reported herein is a follow-up to document prevalence of 58 mental health conditions across 28 years of data from 6078 individuals with DS and 30,326 age- and sex-matched controls. Patient data were abstracted from electronic medical records within a large integrated health system. In general, individuals with DS had higher prevalence of mood disorders (including depression); anxiety disorders (including obsessive-compulsive disorder); schizophrenia; psychosis (including hallucinations); pseudobulbar affect; personality disorder; dementia (including Alzheimer's disease); mental disorder due to physiologic causes; conduct disorder; tic disorder; and impulse control disorder. Conversely, the DS cohort experienced lower prevalence of bipolar I disorder; generalized anxiety, panic, phobic, and posttraumatic stress disorders; substance use disorders (including alcohol, opioid, cannabis, cocaine, and nicotine disorders); and attention-deficit/hyperactivity disorder. Prevalence of many mental health conditions in the setting of DS vastly differs from comparable individuals without DS. These findings delineate a heretofore unclear jumping-off point for ongoing research.

Overexpression of miR-99a in hippocampus leads to impairment of reversal learning in mice

As one of the most common human genetic disorders, Down syndrome (DS) is characterized by a mild-to-moderate cognitive disability, which mainly results from genes overexpression on chromosome 21. The expression of miR-99a, a gene harboring on chromosome 21, is increased by 50 folds in DS brain samples. This study aims to investigate the effect of miR-99a overexpression in the hippocampus on mouse behaviors and explore the underlying mechanisms. Lentivirus vectors were delivered into the hippocampus for focal miR-99a overexpression in mice. Then behaviors were observed by an open field, elevated plus maze, rotarod motor test, and Morris water maze. The genes affected by miR-99a were identified by RNA sequencing (RNA-seq) and confirmed by quantitative RT-PCR (qRT-PCR) in samples isolated from the hippocampus injected with lentivirus-GFP-miR-99a or lentivirus-GFP vectors. It was found that the expression of miR-99a with intrahippocampal delivery of lentivirus-GFP-miR-99a resulted in reversal learning impairment in mice although it had no influence on motor function and anxiety. Meanwhile, RNA-seq results showed that 92 genes including mRNAs and microRNAs were significantly regulated by miR-99a, consistent with qRT-PCR consequence. Moreover, dual-luciferase reporter assay showed that miR-99a could directly bind to the 3'-untranslated regions (3'UTR) of target genes (Clic6 and Kcnj13) with an inhibitory effect on their activity. Furthermore, we also found that miR-99a overexpression affected different biological processes by bioinformatic analyses. Our study showed that miR-99a overexpression in the hippocampus leads to cognitive impairment through regulating the expressions of various genes, which reveals a novel function of miR-99a and provides new insights into understanding the pathophysiologic process of DS.

Parental perspectives on the quality of life of children with Down syndrome

Down Syndrome (DS) is the most common chromosome abnormality and the most frequent cause of developmental delay/intellectual disabilities in children. Although the investigation of the quality of life (QoL) is crucial in children with DS, relatively poor attention has been paid to this topic. The current study aimed to evaluate parent-reported QoL in a group of children with DS and identify children's individual and clinical features associated with different levels of QoL. We included in the study 73 children with DS (5-12 years) and investigated the parent-reported levels of QoL by means of the Pediatric Quality of Life Inventory. Cognitive level and the presence of behavioral difficulties were also evaluated. The overall parent-reported QoL of children with DS was high; emotional functioning was the domain with the highest level of QoL. Moreover, parents perceived low levels of QoL in children who exhibited low IQ, worse analogical reasoning, worse adaptive skills, more frequent challenging behaviors, more ritualistic/sameness behavior and more autistic symptoms. No differences emerged for family variables, namely parental education and employment, between the two groups with high and low QoL, as perceived by parents. The understanding of cognitive and behavioral factors - such as analogical reasoning, socio-communication abilities and challenging behaviors - related with different degrees of QoL in children with DS is crucial for the development of effective strategies to promote the improvement of the QoL.

Assessment of oppositional defiant disorder and oppositional behavior in children and adolescents with Down syndrome

INTRODUCTION

Children and adolescents with intellectual disability (ID) exhibit higher rates of oppositional defiant disorder (ODD) than typically developing (TD) peers. However, studies focusing on the investigation of ODD prevalence in youth with Down syndrome (DS) are still limited.

METHODS

The current study aimed to investigate the prevalence of ODD clinical and subclinical symptoms in a group of 101 youth with DS (63 boys, 38 girls) ranging in age from 6 to 18 years. Moreover, the prevalence of ODD symptoms, as detected by means of three parent-report questionnaires, was compared with that detected by a semi-structured psychopathological interview, namely, the Schedule for Affective Disorders and Schizophrenia for School Aged Children Present and Lifetime (K-SADS) Version Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5).

RESULTS

We found that 17% of participants met diagnostic criteria for ODD on the K-SADS, whereas 24% exhibited subclinical symptoms. Results also suggest good specificity of Swanson, Nolan, and Pelham-IV Rating Scale (SNAP-IV), Conners' Parent Rating Scales Long Version (CPRS) and Child Behavior Checklist (CBCL) in detecting ODD symptoms. The investigation of the agreement in the prevalence rates of clinical and subclinical symptoms of ODD between K-SADS and the parent-report questionnaires indicated CPRS as the parent-report questionnaire with the best agreement with K-SADS.

DISCUSSION

This study provides support for the use of parent-report questionnaires to assess ODD symptoms in children and adolescents with DS by evaluating their levels of agreement with a semi-structured psychopathological interview. In particular, our results suggest that CPRS could be considered a suitable screening tool for ODD clinical and subclinical symptoms in youth with DS.

Early appearance of dendritic alterations in neocortical pyramidal neurons of the Ts65Dn model of Down syndrome

Down syndrome (DS), which is due to triplication of chromosome 21, is constantly associated with intellectual disability (ID). ID can be ascribed to both neurogenesis impairment and dendritic pathology. These defects are replicated in the Ts65Dn mouse, a widely used model of DS. While neurogenesis impairment in DS is a fetal event, dendritic pathology occurs after the first postnatal months. Neurogenesis alterations across the lifespan have been extensively studied in the Ts65Dn mouse. In contrast, there is scarce information regarding dendritic alterations at early life stages in this and other models, although there is evidence for dendritic alterations in adult mouse models. Thus, the goal of the current study was to establish whether dendritic alterations are already present in the neonatal period in Ts65Dn mice. In Golgi-stained brains we quantified the dendritic arbors of layer II/III pyramidal neurons in the frontal cortex of Ts65Dn mice aged 2 (P2) and 8 (P8) days and their euploid littermates. In P2 Ts65Dn mice we found a moderate hypotrophy of the apical and collateral dendrites but a patent hypotrophy of the basal dendrites. In P8 Ts65Dn mice the distalmost apical branches were missing or reduced in number but there were no alterations in the collateral and basal dendrites. No genotype effects were detected on either somatic or dendritic spine density. This study shows dendritic branching defects that mainly involve the basal domain in P2 Ts65Dn mice, and the apical but not the other domains in P8 Ts65Dn mice. This suggests that dendritic defects may be related to dendritic compartment and age. The lack of a severe dendritic pathology in Ts65Dn pups is reminiscent of the delayed appearance of patent dendritic alterations in newborns with DS. This similarly highlights the usefulness of the Ts65Dn model for the study of the mechanisms underlying dendritic alterations in DS and the design of possible therapeutic interventions.

Therapeutic Effects of Catechins in Less Common Neurological and Neurodegenerative Disorders

In recent years, neurological and neurodegenerative disorders research has focused on altered molecular mechanisms in search of potential pharmacological targets, e.g., imbalances in mechanisms of response to oxidative stress, inflammation, apoptosis, autophagy, proliferation, differentiation, migration, and neuronal plasticity, which occur in less common neurological and neurodegenerative pathologies (Huntington disease, multiple sclerosis, fetal alcohol spectrum disorders, and Down syndrome). Here, we assess the effects of different catechins (particularly of epigalocatechin-3-gallate, EGCG) on these disorders, as well as their use in attenuating age-related cognitive decline in healthy individuals. Antioxidant and free radical scavenging properties of EGCG -due to their phenolic hydroxyl groups-, as well as its immunomodulatory, neuritogenic, and autophagic characteristics, makes this catechin a promising tool against neuroinflammation and microglia activation, common in these pathologies. Although EGCG promotes the inhibition of protein aggregation in experimental Huntington disease studies and improves the clinical severity in multiple sclerosis in animal models, its efficacy in humans remains controversial. EGCG may normalize DYRK1A (involved in neural plasticity) overproduction in Down syndrome, improving behavioral and neural phenotypes. In neurological pathologies caused by environmental agents, such as FASD, EGCG enhances antioxidant defense and regulates placental angiogenesis and neurodevelopmental processes. As demonstrated in animal models, catechins attenuate age-related cognitive decline, which results in improvements in long-term outcomes and working memory, reduction of hippocampal neuroinflammation, and enhancement of neuronal plasticity; however, further studies are needed. Catechins are valuable compounds for treating and preventing certain neurodegenerative and neurological diseases of genetic and environmental origin. However, the use of different doses of green tea extracts and EGCG makes it difficult to reach consistent conclusions for different populations.

[Is Neuron-Vascular Communication Disturbed in the Delayed Prenatal Brain Development of a Mouse Model of Down Syndrome?]

Developmental retardation of the brain with reduced cortical neurogenesis is observed in Ts1Cje mice, a model of Down syndrome (DS) as it is in people with DS; however, the mechanisms and the responsible gene(s) remain unknown. The goal of the present study is to establish a therapeutic approach for treating the delayed brain development in DS. To achieve this, we have utilized multiple OMICS analyses, including proteomics and transcriptomics, to uncover the molecular alterations in the brains of DS model mice. Furthermore, we have elucidated that a transcriptional factor, the Erg gene, which is coded in the trisomic region, contributed to reduced cortical neurogenesis in the embryo of a DS mouse model by a molecular genetic technique, the "in vivo gene subtraction method". In the current review, I will introduce our recent work, the identification of the gene responsible for delayed brain development in the DS mouse model and will discuss the possibility that blood vessel dysfunction may be associated with reduced embryonic neurogenesis in DS.

Atypical electrophysiological and behavioral responses to diazepam in a leading mouse model of Down syndrome

Mounting evidence implicates dysfunctional GABA_AR-mediated neurotransmission as one of the underlying causes of learning and memory deficits observed in the Ts65Dn mouse model of Down syndrome (DS). The specific origin and nature of such dysfunction is still under investigation, which is an issue with practical consequences to preclinical and clinical research, as well as to the care of individuals with DS and anxiety disorder or those experiencing seizures in emergency room settings. Here, we investigated the effects of GABA_AR positive allosteric modulation (PAM) by diazepam on brain activity, synaptic plasticity, and behavior in Ts65Dn mice. We found Ts65Dn mice to be less sensitive to diazepam, as assessed by electroencephalography, long-term potentiation, and elevated plus-maze. Still, diazepam pre-treatment displayed typical effectiveness in reducing susceptibility and severity to picrotoxin-induced seizures in Ts65Dn mice. These findings fill an important gap in the understanding of GABAergic function in a key model of DS.

Quality of life in individuals with Down syndrome aged 4 to 21 years

BACKGROUND

To date, investigations of quality of life (QoL) in children with Down syndrome (DS) are rather limited. The purpose of this study was twofold: to examine QoL in children with DS and to explore possible differences in the QoL by age and gender.

METHODS

A cross-sectional study of 211 parents of children with DS was conducted using an online survey that included a consent form, a demographic questionnaire and the English version of KidsLife, which is a measure of children's QoL.

RESULTS

Our results demonstrated moderate or favourable levels of QoL except for the emotional well-being domain among children with DS. The children's QoL showed no variance by gender. However, emotional and material well-being, interpersonal relations and social inclusion varied by age.

CONCLUSIONS

The current findings provide important evidence that will help healthcare, educational and social services professionals to understand the multiple aspects of QoL in children with DS and support parents in their efforts to ensure the child's QoL. The results also point to the need to develop interventions aimed at improving QoL in those areas where children with DS are at increased risk for poorer QoL.

The promotion of physical activity for the prevention of Alzheimer's disease in adults with Down Syndrome: Rationale and design for a 12 Month randomized trial

Nearly all individuals with Down Syndrome (DS) display pathology associated with Alzheimer's disease (AD) beginning as early as age 30. Previous research in typically developed adults suggests that increased moderate-to-vigorous physical activity (MVPA) may improve cognitive function and protect against age-related structural and functional changes in the brain; however, the potential impact of increased MVPA on the development of AD in adults with DS has not been evaluated. Despite the potential positive impact of MVPA on cognition and AD risk, participation in MVPA among young adults with DS is low. The limited research evaluating strategies for increasing MVPA in adults with DS has been unsuccessful in increasing MVPA. Results from our preliminary investigation where we remotely delivered real-time MVPA, led by a trained health educator, to groups of adults with DS in their homes via video conferencing on a tablet computer demonstrated high attendance, increased MVPA during group sessions, and improvements in cognitive function. However, the sustainability, impact on total daily MVPA, optimal session frequency, and potential impacts on cognitive function and brain health of remotely delivered group MVPA sessions in adults with DS are unknown. Therefore, we will conduct a trial in 80 non-demented adults with DS to determine the feasibility and potential efficacy of remotely delivered group MVPA sessions to increase daily MVPA, relative to a usual care control. Secondarily we will assess the impact of MVPA on cardiovascular fitness, quality of life, cognitive function and brain parameters related to AD.

NCT REGISTRATION

NCT04048759.

Neuroanatomical alterations in higher-order thalamic nuclei of fetuses with Down syndrome

OBJECTIVES

Down syndrome (DS) is a genetic condition characterized by cognitive disability starting from infancy. Children with DS exhibit deficits in several cognitive domains, including executive function, i.e., a set of cognitive processes that heavily depend on higher-order thalamic nuclei. The goal of this study was to establish whether executive function-related thalamic nuclei of fetuses with DS exhibit neuroanatomical alterations that may contribute to the defects in higher-order control processes seen in children with DS.

PATIENTS AND METHODS

In brain sections from fetuses with DS and control fetuses (gestational week 17-22), we evaluated the cellularity in the mediodorsal nucleus (MD), the centromedian nucleus (CM), and the parafascicular nucleus (PF) of the thalamus and the density of proliferating cells in the third ventricle.

RESULTS

We found that all three nuclei had a notably reduced cell density. This defect was associated with a reduced density of proliferating cells in the third ventricle, suggesting that the reduced cellularity in the MD, CM, and PF of fetuses with DS was due to neurogenesis impairment. The separate evaluation of projection neurons and interneurons in the MD, CM, and PF showed that in fetuses with DS the density of projection neurons was reduced, with no changes in interneuron density.

CONCLUSION

This study provides novel evidence for DS-linked cellularity alterations in the MD, CM, and PF and suggests that altered signal processing in these nuclei may be involved in the impairment in higher-order control processes observed in individuals with DS starting from infancy.

Rett Syndrome and Other Neurodevelopmental Disorders Share Common Changes in Gut Microbial Community: A Descriptive Review

In this narrative review, we summarize recent pieces of evidence of the role of microbiota alterations in Rett syndrome (RTT). Neurological problems are prominent features of the syndrome, but the pathogenic mechanisms modulating its severity are still poorly understood. Gut microbiota was recently demonstrated to be altered both in animal models and humans with different neurodevelopmental disorders and/or epilepsy. By investigating gut microbiota in RTT cohorts, a less rich microbial community was identified which was associated with alterations of fecal microbial short-chain fatty acids. These changes were positively correlated with severe clinical outcomes. Indeed, microbial metabolites can play a crucial role both locally and systemically, having dynamic effects on host metabolism and gene expression in many organs. Similar alterations were found in patients with autism and down syndrome as well, suggesting a potential common pathway of gut microbiota involvement in neurodevelopmental disorders.

Distribution and age of onset of psychopathological risk in a cohort of children with Down syndrome in developmental age

Background

Aim of the study is to intercept specific characteristics and psychiatric comorbidity in Down Syndrome (DS). The study describes the distribution and the age of specific aspects of behavioral phenotype in a sample of subjects with DS.

Methods

Psychopathological risk has been evaluated in a 97 DS patient cohort, aged 1 to 18 years, during regular follow-up neuropsychiatric visit and through administration of Child Behavior Checklist (CBCL); Childhood Autism Rating Scale (CARS-T) was assessed to verify the presence of autistic behaviors.

Results

The results show the presence of specific psychopathological risk factors in 90% of the sample. 7% of sample presents autistic features. The risk of psychopathology is independent of the degree of intellectual disability.

Conclusion

The high frequency of psychopathological risk factors indicates the need for accurate monitoring to intercept specific characteristics, such as in the case of comorbidity for autism. The search for specific psychopathological factors is a little explored aspect to date, as evidenced by the literature. Despite the studies available to date highlight the presence of psychopathological vulnerability in DS, so far there are only few reports that explore this issue systematically.

Factors associated with depression and anxiety in children with intellectual disabilities

BACKGROUND

Individuals with intellectual disabilities (ID) are at increased risk for depression and anxiety disorders; however, there is a paucity of research that pertains to associative factors for these mental health disorders in this population. The objective of this investigation was to determine factors associated with depression and anxiety problems in children with ID.

METHODS

Children 6-17 years with ID (n = 423; 63% male) from the 2016 National Survey of Children's Health were included in this cross-sectional study. Outcome measures included depression and anxiety problems. Predictor variables included sociodemographics, ID severity, co-morbid conditions (autism spectrum disorders, epilepsy, cerebral palsy, Down syndrome and attention-deficit/hyperactivity disorder), physical factors (i.e. physical activity, sleep duration and pain) and social factors (e.g. participation in activities and bully victimisation). Multivariable logistic regression was performed to determine the association between all factors and depression and/or anxiety problems among children with ID.

RESULTS

The prevalence of depression and/or anxiety problems was 35.4%. After adjusting for sociodemographics, Hispanic race was associated with lower odds [odds ratio (OR), 0.3; 95% confidence interval (CI), 0.1-0.8] of depression and/or anxiety problems. After adjusting for race, co-morbid conditions, and physical and social factors, autism spectrum disorders (OR, 4.4; 95% CI, 1.1-10.1), Down syndrome (OR, 0.2; 95% CI, 0.1-0.8), attention-deficit/hyperactivity disorder (OR, 5.9; 95% CI, 2.5-14.3), pain (OR, 7.0; 95% CI, 2.9-17.1) and bully victimisation (OR 2.3; 95% CI, 1.0-5.3) were each associated with depression and/or anxiety problems.

CONCLUSIONS

The present study identified both treatable and modifiable, as well as unmodifiable, factors associated with depression and/or anxiety problems in children with ID.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

Changes in cognitive function after a 12-week exercise intervention in adults with Down syndrome

BACKGROUND

Between 250,000 and 400,000 individuals in the United States are diagnosed with Down syndrome (DS). Nearly all adults with DS will develop Alzheimer's disease pathology starting in their thirties. Recent studies suggest that increased physical activity (PA) may be important for maintaining components of cognition, including memory.

OBJECTIVE

The purpose of this study was to evaluate changes in cognitive function after completion of a 12-week exercise intervention in adults with DS.

METHODS

Participants were randomized to attend 30-minute group exercise sessions 1 or 2 times a week for 12 weeks. The exercise sessions were delivered via video conferencing on a tablet computer to groups of 5-8 participants. Sessions consisted of aerobic based exercises such as walking and jogging to music, dancing, as well as strength based exercises such as vertical jumps, bicep curls, and squats. Cognitive function was measured at baseline and end of study using the Cantab Dementia Battery for iPads, which assessed the cognitive domains of memory, attention, and reaction time.

RESULTS

Twenty-seven participants (27.9 ± 7.1 years of age, 40.7% female) enrolled and completed the 12-week intervention. Participants randomized to 1 session/week averaged 26.6 ± 3.0 min/week of PA from the group exercise session. Participants randomized to 2 sessions/week averaged 57.7 ± 15.3 min/week of PA from the group exercise sessions. Participants improved their performance on the two memory variables (p = 0.048 and p = 0.069).

CONCLUSION

Increased exercise may have positive changes on memory and other cognitive functions.

Lifespan analysis of brain development, gene expression and behavioral phenotypes in the Ts1Cje, Ts65Dn and Dp(16)1/Yey mouse models of Down syndrome

Down syndrome (DS) results from triplication of human chromosome 21. Neuropathological hallmarks of DS include atypical central nervous system development that manifests prenatally and extends throughout life. As a result, individuals with DS exhibit cognitive and motor deficits, and have delays in achieving developmental milestones. To determine whether different mouse models of DS recapitulate the human prenatal and postnatal phenotypes, here, we directly compared brain histogenesis, gene expression and behavior over the lifespan of three cytogenetically distinct mouse models of DS: Ts1Cje, Ts65Dn and Dp(16)1/Yey. Histological data indicated that Ts65Dn mice were the most consistently affected with respect to somatic growth, neurogenesis and brain morphogenesis. Embryonic and adult gene expression results showed that Ts1Cje and Ts65Dn brains had considerably more differentially expressed (DEX) genes compared with Dp(16)1/Yey mice, despite the larger number of triplicated genes in the latter model. In addition, DEX genes showed little overlap in identity and chromosomal distribution in the three models, leading to dissimilarities in affected functional pathways. Perinatal and adult behavioral testing also highlighted differences among the models in their abilities to achieve various developmental milestones and perform hippocampal- and motor-based tasks. Interestingly, Dp(16)1/Yey mice showed no abnormalities in prenatal brain phenotypes, yet they manifested behavioral deficits starting at postnatal day 15 that continued through adulthood. In contrast, Ts1Cje mice showed mildly abnormal embryonic brain phenotypes, but only select behavioral deficits as neonates and adults. Altogether, our data showed widespread and unexpected fundamental differences in behavioral, gene expression and brain development phenotypes between these three mouse models. Our findings illustrate unique limitations of each model when studying aspects of brain development and function in DS. This work helps to inform model selection in future studies investigating how observed neurodevelopmental abnormalities arise, how they contribute to cognitive impairment, and when testing therapeutic molecules to ameliorate the intellectual disability associated with DS.This article has an associated First Person interview with the first author of the paper.

Obstructive sleep apnea in patients with Down syndrome: current perspectives

For individuals with Down syndrome (DS), obstructive sleep apnea (OSA) is a complex disorder with significant clinical consequences. OSA is seen frequently in DS, and when present, it tends to be more severe. This increased prevalence is likely related to common anatomic abnormalities and a greater risk of additional comorbidities such as hypotonia and obesity. Because signs and symptoms do not often correlate with disease, all children and adults with DS should receive routine screening for OSA. Similar to the general population, polysomnography remains the gold standard for diagnosis. Because individuals with DS may be more susceptible to cardiovascular and neurocognitive sequelae, early diagnosis and treatment of OSA is becoming increasingly important. Treatment options generally involve upper airway surgery (primarily adenotonsillectomy) and continuous positive airway pressure (CPAP); however, various adjunctive therapies including intranasal steroids, palatal expansion, and oropharyngeal exercises are also available. Residual disease status post adenotonsillectomy is common, and further evaluation (eg, drug-induced sleep endoscopy [DISE]) is often needed. More advanced and directed airway surgery can be performed if additional sites of obstruction are observed. Novel therapies including hypoglossal nerve stimulation are emerging as effective treatments for refractory OSA. Due to the diversity among individuals with DS, personalized treatment plans should be developed. Within this arena, opportunities for research remain abundant and should include areas involving patient risk factors, alternative diagnostic methods, and outcome analysis.

Clinical aspects and biomarkers of Alzheimer's disease in Down syndrome

Alzheimer's disease (AD) may affect in excess of 90% of individuals with Down syndrome (DS) after age 60, due to duplication of the APP gene in trisomy of chromosome 21, with neuropathology that is comparable to Sporadic AD and Familial AD (FAD). Previous literature suggested some unique features in clinical presentation of dementia in DS (DSd), which might be due to diagnostic difficulties, or represent a real difference compared to SAD or FAD. We review current knowledge on clinical diagnosis and presentation of dementia in DS in comparison with FAD due to APP mutations and APP duplication. We suggest that the clinical presentation in DS (prominent memory decline and behavioral symptoms, and early development of myoclonus and seizures) are similar to the clinical features associated with APP mutations that is known to have an increased Aβ42/ Aβ40 ratio, and highlight the relative lack of vascular complications associated with cerebral amyloid angiopathy in DS in comparison with those rare individuals with FAD due to duplication APP. We consider the biomarker evidence associated with DS and DSd with reference to Aβ peptide levels and oxidative stress, and suggest future directions for research to explore the potential mechanisms associated with the clinical presentation of DSd.

Aerobic exercise and a BDNF-mimetic therapy rescue learning and memory in a mouse model of Down syndrome

Down syndrome (DS) is caused by the triplication of human chromosome 21 and represents the most frequent genetic cause of intellectual disability. The trisomic Ts65Dn mouse model of DS shows synaptic deficits and reproduces the essential cognitive disabilities of the human syndrome. Aerobic exercise improved various neurophysiological dysfunctions in Ts65Dn mice, including hippocampal synaptic deficits, by promoting synaptogenesis and neurotransmission at glutamatergic terminals. Most importantly, the same intervention also prompted the recovery of hippocampal adult neurogenesis and synaptic plasticity and restored cognitive performance in trisomic mice. Additionally, the expression of brain-derived neurotrophic factor (BDNF) was markedly decreased in the hippocampus of patients with DS. Since the positive effect of exercise was paralleled by increased BDNF expression in trisomic mice, we investigated the effectiveness of a BDNF-mimetic treatment with 7,8-dihydroxyflavone at alleviating intellectual disabilities in the DS model. Pharmacological stimulation of BDNF signaling rescued synaptic plasticity and memory deficits in Ts65Dn mice. Based on our findings, Ts65Dn mice benefit from interventions aimed at promoting brain plasticity, and we provide evidence that BDNF signaling represents a potentially new pharmacological target for treatments aimed at rescuing cognitive disabilities in patients with DS.

Psychological Support for Young Adults with Down Syndrome: Dohsa-Hou Program for Maladaptive Behaviors and Internalizing Problems

Psychological and psychiatric dysfunction is a major problem in a substantial proportion of young adults with Down syndrome. Some patients develop psychiatric issues, such as depressive, obsessive-compulsive, or psychotic-like disorders, in their late adolescence or young adulthood. Furthermore, these individuals may experience moderate to severe emotional and psychological distress. Development of a psychosocial treatment to address these issues is needed in addition to psychotropic medication. The current study reports two cases of young adults with Down syndrome, who presented psychiatric symptoms and marked disruption in their daily lives. These individuals participated in a Dohsa-hou treatment program. Following treatment, adaptive levels, maladaptive behaviors, and internalizing problems were evaluated by the Vineland Adaptive Behavior Scales-II. Participants showed improvement in maladaptive behaviors and internalizing problems; however, improvement in these areas may be influenced by baseline severity of the problems. This case report suggests that Dohsa-hou could be an effective therapeutic approach for maladaptive and internalizing problems in adults with Down syndrome.

Prevalence and treatment of psychiatric disorders other than psychosis in children and adolescents with 22q11DS: Examining associations with social and role functioning

Individuals with chromosome 22q11 deletion syndrome (22q11DS) have high rates of psychotic disorders. Less is known about their psychopathology and how it is treated prior to the peak period of risk for psychotic disorder. There is also a lack of evidence on how functioning is impacted by psychopathology in this population. The aim of this study was to investigate the prevalence and treatment of non-psychotic psychiatric disorders, and how these factors are associated with psychosocial functioning in children and adolescents with 22q11DS. 126 individuals with 22q11DS aged 8-17 participated in the study. Participants were assessed for psychiatric diagnoses, social and role functioning, anxiety and depressive symptoms and IQ. Information on current treatments was collected. 52.4% of the sample presented with at least one psychiatric disorder. Mood and anxiety disorders were the most frequent, followed by behavioural disorder. Individuals with a psychiatric disorder had significantly lower general, role and social functioning. Only 27% of participants with a psychiatric diagnosis were receiving any mental health treatment at the time of assessment. Findings suggest the high prevalence of psychiatric disorders in youth with 22q11DS, which significantly impacts psychosocial functioning. Despite this, psychiatric disorders tend to remain untreated in this population.

[Behaviour problems of children with Down syndrome in preschool-age - Results from the Heidelberg Down syndrome study]

Aims

We report on the frequency and the correlations of behaviour problems among children with Down syndrome in preschool-age.

Method

As part of a longitudinal study 48 mothers of children with Down syndrome completed the German version of the “Strengths and Difficulties Questionnaire” (SDQ-D) and the Parenting Stress Inventory (PSI). The mothers were asked to fill out the questionnaires when the children had a mean age of five years. The results were compared to norms from children with typical development.

Results

Thirty per cent of the children with Down syndrome were rated as abnormal. Specifically, mean scores indicating problems with children of the same age and hyperactivity were elevated. A regression analysis predicting the total problem score of the SDQ-D revealed maternal educational level, optimistic attitude, and subjective parental stress at the age of one year and the degree of behavioural abnormalities at the age of three years as significant influential factors.

Conclusion

Early intervention for Down syndrome children should include supporting parenting competence and coping skills in order to prevent behaviour problems.

The GABAergic Hypothesis for Cognitive Disabilities in Down Syndrome

Down syndrome (DS) is a genetic disorder caused by the presence of a third copy of chromosome 21. DS affects multiple organs, but it invariably results in altered brain development and diverse degrees of intellectual disability. A large body of evidence has shown that synaptic deficits and memory impairment are largely determined by altered GABAergic signaling in trisomic mouse models of DS. These alterations arise during brain development while extending into adulthood, and include genesis of GABAergic neurons, variation of the inhibitory drive and modifications in the control of neural-network excitability. Accordingly, different pharmacological interventions targeting GABAergic signaling have proven promising preclinical approaches to rescue cognitive impairment in DS mouse models. In this review, we will discuss recent data regarding the complex scenario of GABAergic dysfunctions in the trisomic brain of DS mice and patients, and we will evaluate the state of current clinical research targeting GABAergic signaling in individuals with DS.

Impact of maladaptive behavior on school function in Down syndrome

BACKGROUND/AIMS

Individuals with Down syndrome (DS) are at an increased risk for certain maladaptive behaviors. This study characterized maladaptive behavior in school-aged children with DS and examined the extent to which maladaptive behaviors are associated with school function.

METHODS AND PROCEDURES

Participants were 24 students with DS [mean nonverbal mental age (NVMA)=43.83months; mean chronological age (CA)=77.58months] who completed the Leiter Scales of Performance- Revised (Leiter-R; Roid & Miller, 1997). Their teachers completed the Behavior Assessment Scales for Children Version 2 (Reynolds & Kamphaus, 2004), and the School Function Assessment (Coster et al., 1998), measures of maladaptive and adaptive behavior as observed in the school setting.

RESULTS

Findings reveal a maladaptive behavior profile of elevated areas including Aggression, Attention Problems, and Somatization. When examining the association between maladaptive behavior and school function, multivariate regression results indicated a significant association between Aggression and Compliance, and Attention Problems and Task Completion.

CONCLUSIONS AND IMPLICATIONS

Results underscore the importance of developing training for educators regarding the potential impact of maladaptive behavior on school function for students with Down syndrome.

Congenital Heart Defects and Measures of Fetal Growth in Newborns with Down Syndrome or 22q11.2 Deletion Syndrome

OBJECTIVES

To estimate the association between congenital heart defects (CHD) and indices of fetal growth in Down and 22q11.2 deletion syndromes.

STUDY DESIGN

We established 2 Danish nationwide cohorts of newborn singletons with either Down syndrome (n = 670) or 22q11.2 deletion syndrome (n = 155), born 1997-2011. In both cohorts, we analyzed the association between CHD, CHD severity, and indices of fetal growth by multivariable linear regression adjusted for potential confounders. We report mean differences in gestational age specific z-scores compared with newborns without CHD.

RESULTS

Down syndrome and 22q11.2 deletion syndrome were both associated with lower mean birth weight and head circumference z-scores. We found no association between CHD or CHD severity and indices of fetal growth. In Down syndrome, the association between any CHD and the mean difference in head circumference z-score was 0.03 (95% CI -0.12, 0.18), and the estimate regarding birth weight z-score was 0.09 (95% CI -0.08, 0.25). The corresponding estimates in 22q11.2 deletion syndrome were 0.00 (95% CI -0.33, 0.32) and -0.09 (95% CI -0.45, 0.26).

CONCLUSIONS

We found no association between CHD and fetal growth measures in newborns with Down syndrome or 22q11.2 deletion syndrome. Thus, in certain subtypes of CHD, the contribution of genetic factors to prenatal growth impairment may be more important than circulatory disturbances.

Absence of Prenatal Forebrain Defects in the Dp(16)1Yey/+ Mouse Model of Down Syndrome

Studies in humans with Down syndrome (DS) show that alterations in fetal brain development are followed by postnatal deficits in neuronal numbers, synaptic plasticity, and cognitive and motor function. This same progression is replicated in several mouse models of DS. Dp(16)1Yey/+ (hereafter called Dp16) is a recently developed mouse model of DS in which the entire region of mouse chromosome 16 that is homologous to human chromosome 21 has been triplicated. As such, Dp16 mice may more closely reproduce neurodevelopmental changes occurring in humans with DS. Here, we present the first comprehensive cellular and behavioral study of the Dp16 forebrain from embryonic to adult stages. Unexpectedly, our results demonstrate that Dp16 mice do not have prenatal brain defects previously reported in human fetal neocortex and in the developing forebrains of other mouse models, including microcephaly, reduced neurogenesis, and abnormal cell proliferation. Nevertheless, we found impairments in postnatal developmental milestones, fewer inhibitory forebrain neurons, and deficits in motor and cognitive performance in Dp16 mice. Therefore, although this new model does not express prenatal morphological phenotypes associated with DS, abnormalities in the postnatal period appear sufficient to produce significant cognitive deficits in Dp16.

Motor, linguistic, personal and social aspects of children with Down syndrome

A global developmental delay is expected from Down syndrome, affecting motor, cognitive, linguistic and personal-social skills. However, not always these delays are proportional; different conditions occur due to several intrinsic and extrinsic variables that must be controlled to form groups of greater homogeneity.

Longitudinal measures of cognition in the Ts65Dn mouse: Refining windows and defining modalities for therapeutic intervention in Down syndrome

Mouse models have provided insights into adult changes in learning and memory in Down syndrome, but an in-depth assessment of how these abnormalities develop over time has never been conducted. To address this shortcoming, we conducted a longitudinal behavioral study from birth until late adulthood in the Ts65Dn mouse model to measure the emergence and continuity of learning and memory deficits in individuals with a broad array of tests. Our results demonstrate for the first time that the pace at which neonatal and perinatal milestones are acquired is correlated with later cognitive performance as an adult. In addition, we find that life-long behavioral indexing stratifies mice within each genotype. Our expanded assessment reveals that diminished cognitive flexibility, as measured by reversal learning, is the most robust learning and memory impairment in both young and old Ts65Dn mice. Moreover, we find that reversal learning degrades with age and is therefore a useful biomarker for studying age-related decline in cognitive ability. Altogether, our results indicate that preclinical studies aiming to restore cognitive function in Ts65Dn should target both neonatal milestones and reversal learning in adulthood. Here we provide the quantitative framework for this type of approach.

Psychotropic Medication Use in Children and Adolescents With Down Syndrome

OBJECTIVE

To estimate the rate of psychotropic medication use in children and adolescents with Down syndrome (DS) and to describe age-related trends.

METHODS

Data were obtained from electronic health records from 2010 to 2013 for a retrospective cohort of 832 children with DS, aged 5 to 21 years, including 5324 visits. The following medication classes: central nervous system (CNS) stimulants, selective serotonin reuptake inhibitors, atypical antipsychotics, and alpha adrenergic agonists were examined. The distribution of rates of medication use across ages was assessed graphically and with the Cochran-Armitage trend test. Between-group comparisons of medication classes were conducted using χ. Repeated measures models with generalized estimating equations were used to assess changes in rates of medication use over time.

RESULTS

Children aged 12 to 21 years were more likely to be on any medication at some point compared with children aged 5 to 11 years (25% vs 17%, respectively, p = .003). For 5 to 11 year olds, the odds of being on a psychotropic medication increased with age for all medication classes studied. For 12 to 18 year olds, the odds of being on a CNS stimulant significantly decreased with increasing age (odds ratio: 0.73, 95% confidence intervals, 0.58-0.91), whereas the odds of being on a medication from one of the other classes was stable.

CONCLUSION

Changes in psychotropic medication use across the age span in children with DS suggest that the type and severity of neurobehavioral problems in this population likely also change over time. These findings will inform future research on the common mental health conditions and treatments for children with DS.

Placebo Responses in Genetically Determined Intellectual Disability: A Meta-Analysis

Background

Genetically determined Intellectual Disability (ID) is an intractable condition that involves severe impairment of mental abilities such as learning, reasoning and predicting the future. As of today, little is known about the placebo response in patients with ID.

Objective

To determine if placebo response exists in patients with genetically determined ID.

Data sources and Study selection

We searched Medline/PubMed, EMBASE, CENTRAL and PsycINFO to find all placebo-controlled double-blind randomized clinical trials (RCTs) in patients with genetically determined ID, published up to April 2013, focusing on core ID symptoms.

Data extraction and synthesis

Two investigators extracted outcome data independently.

Main outcomes and measures

Bias-corrected standardized mean difference (Hedge’s g) was computed for each outcome measure, using the Comprehensive Meta-Analysis software. A priori defined patient sub-groups were analyzed using a mixed-effect model. The relationship between pre-defined continuous variable moderators (age, IQ, year of publication and trial duration) and effect size was analyzed using meta-regression

Results

Twenty-two placebo-controlled double-blind RCTs met the inclusion criteria (n = 721, mean age = 17.1 years, 62% men, mean trial duration = 35 weeks). There was a significant overall placebo response from pre- to post-treatment in patients with ID (g = 0.468, p = 0.002), both for “subjective outcomes” (a third-person’s evaluation of the patient) (g = 0.563, p = 0.022) and “objective outcomes” (direct evaluation of the patient’s abilities) (g = 0.434, p = 0.036). Individuals with higher IQ had higher response to placebo (p = 0.02) and no placebo response was observed in ID patients with comorbid dementia. A significant effect of age (p = 0.02) was found, indicating higher placebo responses in treatment of younger patients.

Conclusions and relevance

Results suggest that patients with genetically determined ID improve in the placebo arm of RCTs. Several mechanisms may contribute to placebo effects in ID, including expectancy, implicit learning and “placebo-by-proxy” induced by clinicians/family members. As the condition is refractory, there is little risk that improvements are explained by spontaneous remission. While new avenues for treatment of genetically determined ID are emerging, our results demonstrate how contextual factors can affect clinical outcomes and emphasize the importance of being vigilant on the role of placebos when testing novel treatments in ID.

Dementia in intellectual disability

PURPOSE OF REVIEW

Dementia is emerging as a significant condition in the population with intellectual disability. This review is aimed at clinicians working in the field. We revisit what is known on the subject and expand on this with results from recent research. The emphasis of this review is on the clinical research rather than laboratory or molecular research.

RECENT FINDINGS

Research has encompassed all aspects of dementia in intellectual disability, from epidemiology, assessment and diagnosis, through to management. There remains a lack of evidence concerning both pharmacological and nonpharmacological treatment of dementia in people with intellectual disability. Recent research has tended to focus on dementia in Down syndrome.

SUMMARY

More research is necessary in order to translate improvements in the understanding of the neuropathology of intellectual disability and dementia into effective treatments. There is also a need to investigate the optimum environment in which to provide holistic care for individuals affected.