Training spatial-simultaneous working memory in individuals with Down syndrome

Transcranial Direct Current Stimulation in neurogenetic syndromes: new treatment perspectives for Down syndrome?

This perspective review aims to explore the potential neurobiological mechanisms involved in the application of transcranial Direct Current Stimulation (tDCS) for Down syndrome (DS), the leading cause of genetically-based intellectual disability. The neural mechanisms underlying tDCS interventions in genetic disorders, typically characterized by cognitive deficits, are grounded in the concept of brain plasticity. We initially present the neurobiological and functional effects elicited by tDCS applications in enhancing neuroplasticity and in regulating the excitatory/inhibitory balance, both associated with cognitive improvement in the general population. The review begins with evidence on tDCS applications in five neurogenetic disorders, including Rett, Prader-Willi, Phelan-McDermid, and Neurofibromatosis 1 syndromes, as well as DS. Available evidence supports tDCS as a potential intervention tool and underscores the importance of advancing neurobiological research into the mechanisms of tDCS action in these conditions. We then discuss the potential of tDCS as a promising non-invasive strategy to mitigate deficits in plasticity and promote fine-tuning of the excitatory/inhibitory balance in DS, exploring implications for cognitive treatment perspectives in this population.

Psychometric evaluation of a working memory assessment measure in young children with Down syndrome

BACKGROUND

Working memory involves the temporary storage and manipulation of information and is frequently an area of challenge for individuals with Down syndrome (DS). Despite the potential benefits of intervention, laboratory assessments of working memory that could capture intervention effects have not undergone rigorous evaluation for use with young children with DS. It is critical to evaluate assessments of working memory in young children with DS to ensure the reliable and accurate measurement of performance.

AIM

This study evaluated an adapted laboratory measure of working memory for young children with DS 2-8 years old.

METHOD

A self-ordered pointing task, the Garage Game, was administered to 78 children with DS (mean = 5.17 years; SD = 1.49). Adaptations were made to the task to minimize potential DS phenotype-related language and motor confounds.

RESULTS

Results indicate that the measure is feasible, scalable, and developmentally sensitive, with minimal floor and practice effects for this population within this chronological and developmental age range.

CONCLUSION

These findings demonstrate that the Garage Game is promising for use in studies of early working memory and treatment trials that aim to support the development of this critical dimension of executive functioning for children with DS.

Multi-domain computerized cognitive training for children with intellectual developmental disorder: A randomized controlled trial

Purpose

To verify the effects of multi-domain computerized cognitive training on intellectual function and adaptive functioning in children with intellectual developmental disorder (IDD).

Methods

Children with IDD were randomized to a multi-domain computerized cognitive training (CCT) group (n = 30) and control group (n = 30). Both groups received a 5-week training program. Intellectual function was assessed by Chinese-Wechsler Young Children scale (C-WYCSI) and adaptive functioning was assessed by the Chinese Vineland Adaptive Behavior Rating Scale (VABS-C), which were used at baseline, post-training, and 3-month follow-up.

Results

There were significant differences for intellectual function and adaptive functioning between the two groups. The CCT group showed significant improvements in total full-scale intelligence quotient (FSIQ) score the Wechsler Intelligence Scale (F[60] = 31.97, p < 0.01) and its subdomain VIQ score (F[60] = 33.83, p < 0.01). For adaptive functioning, CCT had a better adaptive developmental quotient (ADQ) score (F[60] = 28.05, p < 0.01), and subdomain communication (F[60] = 10.86, p < 0.01) and socialization scores (F[60] = 4.35, p < 0.015). Moreover, there was a positive correlation between FSIQ changes and ADQ changes in the CCT group (r_s = 0.74, p < 0.01). A greater increase in VIQ score was associated with a greater increase in adaptive functioning (bootstrapping CI: [0.16, 3.30]) in the CCT group.

Conclusion

Multi-domain CCT improves the intellectual function and adaptive functioning of children with IDD.

Evaluating working memory outcome measures for children with Down syndrome

BACKGROUND

There is a critical need for the psychometric evaluation of outcome measures to be used in clinical trials targeting cognition in Down syndrome (DS). This study examines a specific cognitive skill that is of particular importance in DS, working memory, and the psychometric properties of a set of standardised measurements to assess working memory in individuals with DS.

METHODS

Ninety children and adolescents ages 6 to 18 years old with DS were assessed on a selection of verbal and visuospatial working memory subtests of standardised clinical assessments at two time points to examine feasibility, distributional qualities, test-retest reliability and convergent validity against a priori criteria. Caregivers also completed an adaptive behaviour questionnaire to address working memory subtests' associations with broader developmental functioning.

RESULTS

The Stanford Binet-5 Verbal Working Memory, Differential Ability Scales-2 Recognition of Pictures, Stanford Binet-5 Nonverbal Working Memory and Wechsler Intelligence Scale for Children-5 Picture Span measures met the most psychometric criteria overall across the full age and IQ range of the study. Although Differential Ability Scales-2 Recall of Sequential Order and Differential Ability Scales-2 Recall of Digits Backward met the fewest a priori criteria, follow-up analyses suggested greater feasibility in specific age and IQ ranges.

CONCLUSIONS

Several working memory measures appear to be psychometrically sound and appropriate for use in clinical trials for children with DS, especially when focusing on raw scores. However, floor effects on standard scores and feasibility of some measures were problematic. Guidelines for use of the working memory subtests with this population are provided.

Behavioral and Cognitive Interventions With Digital Devices in Subjects With Intellectual Disability: A Systematic Review

In recent years, digital devices have been progressively introduced in rehabilitation programs and have affected skills training methods used with children and adolescents with intellectual disabilities (ID). The objective of this review is to assess the effects of the use of digital devices on the cognitive functions and behavioral skills in this population, and to acknowledge their potential as a therapeutic tool. Electronic databases were analyzed until February 2020 using search formulas with free terms related to ID and the use of digital systems with children or adolescents. The risk of bias in randomized controlled trials was assessed by means of the modified Cochrane Collaboration tool and the quality level of the non-randomized studies was assessed using the Newcastle-Ottawa Scale. Forty-four studies were analyzed, most of which were categorized as low quality. Of the executive function studies analyzed, 60% reported significant improvements, most commonly related to working memory. Within the cognitive skills, 47% of the studies analyzed reported significant improvements, 30% of them in language. Significant improvements in the social (50%) and behavioral domains (30%) were also reported. These results suggest that digital interventions are effective in improving working memory and academic skills, and positively affect both the social and behavioral domains. Little information has been published regarding the duration of the effects, which could be limited in time. Further research is necessary to assess long-term effectiveness, the influence of comorbidities, and the effects on subjects with severe ID. The inclusion of smartphones and special education centers is also necessary.

Feasibility of a Tablet-Based Program for Training Everyday Planning in Adolescents With Intellectual Disabilities

Background

Individuals with intellectual disabilities (ID) show difficulties with everyday planning. A tablet-based training program for everyday planning may be a suitable intervention, but its feasibility must be evaluated. This study evaluated how behavior changes during training and if individuals with ID can use technology by themselves.

Method

Thirty-three adolescents with ID and 30 younger children with a typical development were recruited. The participants were instructed to train in school for a total of 300 minutes. After the intervention, the participants were matched on mental age (MA).

Results

Only 16% of the participants trained for all 300 minutes. Participants in the MA group trained for a longer time than the ID group. Both groups made fewer errors per task at the end compared to the beginning. Individuals with ID started off making less attempts per task and increased their activity during the training. This pattern was not seen in the comparison group.

Conclusions

Both groups used the program independently, without adult supervision. However, a large group of participants in the ID group had a low usage time. Thus, the program might not have been feasible for that subgroup. The ID group increased their activity during the training which might mirror a strategy development of how to use the program. The change in behavior in activity on task attempts can be interpreted such that individuals with ID need a longer time to get familiarized with the technology. Tablet-based training programs are feasible for individuals with ID, but it is necessary to follow up on usage time.

Path Learning in Individuals With Down Syndrome: The Floor Matrix Task and the Role of Individual Visuo-Spatial Measures

Environment learning is essential in everyday life. In individuals with Down syndrome (DS), this skill has begun to be examined using virtual exploration. Previous studies showed that individuals with DS can learn and remember paths in terms of sequences of turns and straight stretches, albeit with some difficulty, and this learning is supported by their cognitive abilities. This study further investigates environment learning in the DS population, newly examining their ability to learn a path from actual movements, and to learn increasingly long paths, and how their performance relates to their visuo-spatial abilities and everyday spatial activities. A group of 30 individuals with DS and 30 typically-developing (TD) children matched for receptive vocabulary performed a 4 × 4 Floor Matrix task in a grid comprising 16 squares (total area 2.3 × 2.3 meters). The task involved repeating increasingly long sequences of steps by actually moving in the grid. The sequences were presented in two learning conditions, called Observation (when participants watched the experimenter’s moves), or Map (when they were shown a map reproducing the path). Several visuo-spatial measures were also administered. The results showed a clear difference between the two groups’ performance in the individual visuo-spatial measures. In the Floor Matrix task, after controlling for visuo-spatial reasoning ability, both groups benefited to the same degree from the Observation condition vis-à-vis the Map condition, and no group differences emerged. In the group with DS, visuo-spatial abilities were more predictive of performance in the Floor Matrix task in the Observation condition than in the Map condition. The same was true of the TD group, but this difference was much less clear-cut. The visuo-spatial working memory and visualization tasks were the strongest predictors of Floor Matrix task performance. Finally, the group with DS showed a significant relation between Floor Matrix task performance in the Observation condition and everyday spatial activity. These results enlarge on what we know about path learning in individuals with DS and its relation to their visuo-spatial abilities. These findings are discussed within the frame of spatial cognition and the atypical development domain.