Adaptive behavior in adolescents and adults with Down syndrome: Results from a 6-month longitudinal study

Insomnia Symptoms Are Associated with Measures of Functional Deterioration and Dementia Status in Adults with Down Syndrome at High Risk for Alzheimer's Disease

Background

While obstructive sleep apnea (OSA) and insomnia symptoms in neurotypical populations are associated with Alzheimer's disease (AD), their association with dementia in adults with Down syndrome (DS) remains less clear, even though these symptoms are prevalent and treatable in DS. Understanding their associations with AD-related dementia status, cognitive impairment, and functional deterioration may lead to interventions to slow decline or disease progression in adults with DS.

Objective

To characterize differences in OSA and insomnia symptom expression by dementia status, and to determine which sleep factors support dementia diagnosis.

Methods

Multimodal consensus conference was used to determine dementia status in 52 adults with DS (52.2 ± 6.4 years, 21 women). Cognitive impairment, adaptive behavior skills, and symptoms of OSA and insomnia were quantified using validated assessments for adults with DS and their primary informants.

Results

A sex by dementia status interaction demonstrated that older women with DS and dementia had more severe terminal insomnia but not OSA symptoms relative to older women with DS who were cognitively stable (CS). Greater insomnia symptom severity was associated with greater functional impairments in social and self-care domains adjusting for age, sex, premorbid intellectual impairment, and dementia status.

Conclusions

Insomnia symptoms are more severe in women with DS with dementia than in women with DS and no dementia, and regardless of dementia status or sex, more severe insomnia symptoms are associated with greater impairment in activities of daily living. These findings underscore the potential importance of early insomnia symptom evaluation and treatment in women with DS at risk of developing AD.

Cross-sectional developmental trajectories in the adaptive functioning of children and adolescents with Down syndrome

BACKGROUND

Persons with Down syndrome (DS) reveal adaptive functioning (AF) difficulties. Studies on AF in DS have focused mainly on describing the profile (i.e., strengths in socialization, and weaknesses in communication), while less is known about age-related differences. This study aimed to elucidate how AF changes with age in children and adolescents with DS, taking a cross-sectional developmental trajectory approach. Moreover, the contribution of both chronological age (CA) and mental age (MA) on AF development was explored.

METHOD

This study involved 115 children and adolescents (between 3 and 16 years old) with DS. Parents were interviewed about their children's AF on communication, daily living and socialization skills. Children and adolescents with DS were assessed on their developmental level.

RESULTS

While participants' standard scores on AF decreased linearly over time, their age-equivalent scores increased with linear or segmented patterns, depending on the skill considered. CA and MA were related to daily living skills and socialization to much the same degree, while MA correlated more strongly than CA with communication.

CONCLUSION

This study contributes to the understanding of how AF develops in children and adolescents with DS, showing that CA and MA both contribute to shaping the skills involved.

Adaptive behaviour in adolescents and adults with Dravet syndrome

AIM

To explore the feasibility of using an adaptive behaviour profile (ABP) assessment generated from a well-known measure-the Vineland Adaptive Behavior Scales, Second Edition (VABS-II)-as an instrument for outcome measures in adolescents and adults with Dravet syndrome.

METHOD

We administered the VABS-II to 35 adolescents and adults with Dravet syndrome (15 males; mean age 24 years, SD 8 years, range: 12-46 years) and collected epilepsy history and neurological features at the time of assessment. We conducted a cross-sectional analysis of VABS-II raw scores and performed cluster analysis to identify different subgroups. We then explored possible relationships between clinical and epilepsy features, ABPs, and age.

RESULTS

Most participants obtained the minimum standard scores in the various VABS-II subdomains, while the raw score analysis outlined interindividual and intraindividual differences among skills. We found two subpopulations: one with a 'lower' ABP and one with a 'higher' ABP, corresponding respectively to individuals in whom myoclonic seizures or generalized spike-and-wave activity were present ('complete phenotype') or absent ('incomplete phenotype') on electroencephalography.

INTERPRETATION

This study further delineates the natural history of Dravet syndrome. The assessment of an ABP through the VABS-II raw score analysis provides a means by which to illustrate profiles of adaptive behaviour in adolescents and adults with Dravet syndrome but shows limitations related to poor sensitivity in measuring fine clinical details. There is a need for new and more specific tools to monitor patients with developmental and epileptic encephalopathies.

A randomized, double-blind, placebo-controlled phase II trial to explore the effects of a GABAA-α5 NAM (basmisanil) on intellectual disability associated with Down syndrome

Background

There are currently no pharmacological therapies to address the intellectual disability associated with Down syndrome. Excitatory/inhibitory imbalance has been hypothesized to contribute to impairments in cognitive functioning in Down syndrome. Negative modulation of the GABA_A-α5 receptor is proposed as a mechanism to attenuate GABAergic function and restore the excitatory/inhibitory balance.

Methods

Basmisanil, a selective GABA_A-α5 negative allosteric modulator, was evaluated at 120 mg or 240 mg BID (80 or 160 mg for 12–13 years) in a 6-month, randomized, double-blind, placebo-controlled phase II trial (Clematis) for efficacy and safety in adolescents and young adults with Down syndrome. The primary endpoint was based on a composite analysis of working memory (Repeatable Battery for the Assessment of Neuropsychological Scale [RBANS]) and independent functioning and adaptive behavior (Vineland Adaptive Behavior Scales [VABS-II] or the Clinical Global Impression-Improvement [CGI-I]). Secondary measures included the Behavior Rating Inventory of Executive Functioning-Preschool (BRIEF-P), Clinical Evaluation of Language Fundamentals (CELF-4), and Pediatric Quality of Life Inventory (Peds-QL). EEG was conducted for safety monitoring and quantitatively analyzed in adolescents.

Results

Basmisanil was safe and well-tolerated; the frequency and nature of adverse events were similar in basmisanil and placebo arms. EEG revealed treatment-related changes in spectral power (increase in low ~ 4-Hz and decrease in high ~ 20-Hz frequencies) providing evidence of functional target engagement. All treatment arms had a similar proportion of participants showing above-threshold improvement on the primary composite endpoint, evaluating concomitant responses in cognition and independent functioning (29% in placebo, 20% in low dose, and 25% in high dose). Further analysis of the individual measures contributing to the primary endpoint revealed no difference between placebo and basmisanil-treated groups in either adolescents or adults. There were also no differences across the secondary endpoints assessing changes in executive function, language, or quality of life.

Conclusions

Basmisanil did not meet the primary efficacy objective of concomitant improvement on cognition and adaptive functioning after 6 months of treatment, despite evidence for target engagement. This study provides key learnings for future clinical trials in Down syndrome.

Trial registration

The study was registered on December 31, 2013, at clinicaltrials.gov as NCT02024789.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09418-0.

Executive functions and adaptive behaviour in individuals with Down syndrome

BACKGROUND

Previous research has explored executive functions (EFs) and adaptive behaviour in children and adolescents with Down syndrome (DS), but there is a paucity of research on the relationship between the two in this population. This study aims to shed light on the profile of EFs and adaptive behaviour in DS, exploring the differences by age and investigating the relationship between these two domains.

METHOD

Parents/caregivers of 100 individuals with DS from 3 to 16 years old participated in the study. The sample was divided into preschoolers (3-6.11 years old) and school-age children (7-16 years old). Parents/caregivers completed either the Preschool Version of the Behaviour Rating Inventory of Executive Function (for children 2-6.11 years old) or the Second Edition of the same Inventory (for individuals 7 + years old). Adaptive behaviour was assessed with the Vineland Adaptive Behaviour Scale - Interview, Second Edition.

RESULTS

Findings suggest that individuals with DS have overall difficulties, but also patterns of strength and weakness in their EFs and adaptive behaviour. The preschool-age and school-age children's EF profiles differed slightly. While both age groups showed Emotional Control as a relative strength and Working Memory as a weakness, the school-age group revealed further weaknesses in Shift and Plan/Organise. As concerns adaptive behaviour, the profiles were similar in the two age groups, with Socialisation as a strength, and Communication and Daily Living Skills as weaknesses, but with a tendency for preschoolers to obtain intermediate scores for the latter. When the relationship between EFs and adaptive behaviour was explored, Working Memory predicted Communication in the younger group, while in the older group the predictors varied, depending on the adaptive domains: Working Memory was a predictor of Communication, Inhibit of Daily Living Skills, and Inhibit and Shift of Socialisation.

CONCLUSION

As well as elucidating the EF profiles and adaptive behaviour in individuals with DS by age, this study points to the role of EFs in adaptive functioning, providing important information for targeted interventions.

Is the Age of Developmental Milestones a Predictor for Future Development in Down Syndrome?

Down Syndrome (DS) is the most common genetic alteration responsible for intellectual disability, which refers to deficits in both intellectual and adaptive functioning. According to this, individuals with Down Syndrome (DS) reach developmental milestones (e.g., sitting, walking, and babbling) in the same order as their typically developing peers, but later in life. Since developmental milestones are the first blocks on which development builds, the aims of the current study are to: (i) expand the knowledge of developmental milestone acquisition; and (ii) explore the relationship between developmental milestone acquisition and later development. For this purpose 105 children/adolescents with DS were involved in this study, divided in two groups, Preschoolers (n = 39) and School-age participants (n = 66). Information on the age of acquisition of Sitting, Walking, Babbling, and Sphincter Control was collected, together with cognitive, motor, and adaptive functioning. Sitting predicted later motor development, but, with age, it became less important in predicting motor development in everyday life. Babbling predicted later language development in older children. Finally, Sphincter Control emerged as the strongest predictor of motor, cognitive, language, and adaptive skills, with its role being more evident with increasing age. Our data suggest that the age of reaching the milestones considered in the study has an influence on successive development, a role that can be due to common neural substrates, the environment, and the developmental cascade effect.