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

Measuring spatial navigation during locomotion in children: A systematic review

Spatial navigation allows us to move around our environment, walking being the most advanced form of human locomotion. Over the years, a range of tools has been developed to study spatial navigation in children. Aim. To describe the role of locomotion during the assessment of spatial navigation in children, providing an overview of the instruments available for assessing spatial navigation in typically developing children and those with neurodevelopmental disorders. Methods and Procedures. A systematic search was performed in six electronic databases between December 2022 and February 2023, then updated in July 2023. Cross-sectional and observational studies were included. Outcomes and results. Of the 3,385 studies screened, 47 were selected for this review. Five studies described the influence of locomotion on spatial navigation, and seven studies included locomotion as an explanatory variable in this area. Most studies focused on children from five to twelve years old, whereas only nine were centred on infants and preschoolers. Just eight assessed spatial abilities in individuals with neurodevelopmental disorders. Conclusions and implications. Children with or at risk of neurodevelopmental impairments show poorer spatial navigation skills. Having the choice to actively explore the space is more important than the way they locomote. It is necessary to have tools to assess spatial navigation during locomotion early in infancy.

A profile of spatial abilities in people with Down syndrome

BACKGROUND

Spatial abilities are fundamental cognitive abilities, have direct applications in daily life, serve as a cognitive foundation for many other complex skills and are used in many specialty jobs. The current study aimed to systematically and comprehensively evaluate the spatial abilities of individuals with Down syndrome (DS) relative to mental ability-matched typically developing (TD) children based on Newcombe and Shipley's double-dimension theoretical framework for classifying spatial abilities.

METHODS

Forty adolescents and young adults with DS and 40 TD children completed a nonverbal intelligence test (Raven's), two measures of static-extrinsic skills (water-level task and cart task), two measures of static-intrinsic skills (figure ground and form completion), two measures of dynamic-extrinsic skills (three mountains task and dog task) and two measures of dynamic-intrinsic spatial skills (mental rotation task and block design task).

RESULTS

Participants with DS showed reduced performance on two dynamic-intrinsic tasks and one static-extrinsic task (i.e. cart task) relative to TD children. Performances were similar in two dynamic-extrinsic tasks and two static-intrinsic tasks. Analyses of composite accuracy for each spatial category further confirmed deficits in dynamic-intrinsic and static-extrinsic categories for people with DS relative to TD children.

CONCLUSIONS

Our results showed an uneven profile of spatial abilities in people with DS relative to ability-matched TD children with particular weaknesses in comprehending and manipulating dynamic-intrinsic and static-extrinsic spatial relations. Furthermore, our research has important clinical implications for more targeted interventions to improve spatial abilities in people with DS.

A Role for Visual Memory in Vocabulary Development: A Systematic Review and Meta-Analysis

Although attention and early associative learning in preverbal children is predominantly driven by rapid eye-movements in response to moving visual stimuli and sounds/words (e.g., associating the word "bottle" with the object), the literature examining the role of visual attention and memory in ongoing vocabulary development across childhood is limited. Thus, this systematic review and meta-analysis examined the association between visual memory and vocabulary development, including moderators such as age and task selection, in neurotypical children aged 2-to-12 years, from the brain-based perspective of cognitive neuroscience. Visual memory tasks were classified according to the visual characteristics of the stimuli and the neural networks known to preferentially process such information, including consideration of the distinction between the ventral visual stream (processing more static visuo-perceptual details, such as form or colour) and the more dynamic dorsal visual stream (processing spatial temporal action-driven information). Final classifications included spatio-temporal span tasks, visuo-perceptual or spatial concurrent array tasks, and executive judgment tasks. Visuo-perceptual concurrent array tasks, reliant on ventral stream processing, were moderately associated with vocabulary, while tasks measuring spatio-temporal spans, associated with dorsal stream processing, and executive judgment tasks (central executive), showed only weak correlations with vocabulary. These findings have important implications for health professionals and researchers interested in language, as they advocate for the development of more targeted language learning interventions that include specific and relevant aspects of visual processing and memory, such as ventral stream visuo-perceptual details (i.e., shape or colour).

Path Learning in Individuals With Down Syndrome: The Challenge of Learning Condition and Cognitive Abilities

Analyzing navigational abilities and related aspects in individuals with Down syndrome (DS) is of considerable interest because of its relevance to everyday life. This study investigates path learning, the conditions favoring it, and the cognitive abilities involved. A group of 30 adults with DS and 32 typically-developing (TD) children matched on receptive vocabulary were shown a 4 × 4 Floor Matrix and asked to repeat increasingly long sequences of steps by walking on the grid. The sequences were presented under two learning conditions, one called Oral instructions (participants received verbal instructions such as “turn right” or “turn left”), the other Observation (participants watched the experimenter's moves). Participants were also assessed on verbal and visuospatial cognitive measures. The results showed a similarly better performance in both groups when the Floor Matrix task was administered in the Observation as opposed to the Oral instructions condition. As for the relation with cognitive abilities, in the Floor Matrix task in the Oral instructions condition, individuals with DS showed an effect of both verbal and visuospatial abilities, which was only positive for verbal ability. The effect of verbal and visuospatial abilities was negligible in the TD group. In the Observation condition, performance was predicted by sequential working memory in both groups. Overall, these results shed light on path learning in individuals with DS, showing that they benefited from the Observation condition, and that the involvement of their cognitive abilities depended on the learning condition.

A Critical Review of Spatial Abilities in Down and Williams Syndromes: Not All Space Is Created Equal

Down syndrome (DS, Trisomy 21) and Williams syndrome (WS) are two neurodevelopmental disorders of genetic origin that are accompanied by mild to moderate intellectual disability but exhibit distinct cognitive profiles. In this review we discuss our recent work characterizing the real-world spatial learning and memory abilities of adult individuals with DS and WS. We used several different paradigms in which participants locomote freely and have access to coherent input from all sensory modalities to investigate their fundamental egocentric (body-centered or viewpoint-dependent) and allocentric (world-centered or viewpoint-independent) spatial abilities. We found unequivocal evidence that most individuals with DS exhibit low-resolution egocentric and allocentric spatial learning and memory abilities similar to typically developing (TD) children in the same mental age range. In contrast, most individuals with DS exhibit impaired high-resolution allocentric spatial learning and facilitated response learning as compared to TD children. In comparison, whereas most individuals with WS also exhibit facilitated response learning, their low-resolution allocentric spatial learning and memory abilities are severely impaired as compared to both TD children and individuals with DS. Together with work from other laboratories using real-world or virtual reality paradigms, these findings indicate that in order to navigate in their environment most individuals with DS may use either egocentric route learning that does not integrate individual landmarks, or a low-resolution allocentric spatial representation that encodes the relationships between different locations (i.e., cognitive mapping). In contrast, since most individuals with WS are unable to build or use a low-resolution allocentric or configural representation of the environment they may use visually and verbally encoded landmarks as beacons to learn routes. Finally, we discuss the main neural structures implicated in these different spatial processes and explain how the relative preservation or impairment of specific brain functions may engender the unique cognitive profiles observed in individuals with these neurodevelopmental disorders.

Path Integration and Cognitive Mapping Capacities in Down and Williams Syndromes

Williams (WS) and Down (DS) syndromes are neurodevelopmental disorders with distinct genetic origins and different spatial memory profiles. In real-world spatial memory tasks, where spatial information derived from all sensory modalities is available, individuals with DS demonstrate low-resolution spatial learning capacities consistent with their mental age, whereas individuals with WS are severely impaired. However, because WS is associated with severe visuo-constructive processing deficits, it is unclear whether their impairment is due to abnormal visual processing or whether it reflects an inability to build a cognitive map. Here, we tested whether blindfolded individuals with WS or DS, and typically developing (TD) children with similar mental ages, could use path integration to perform an egocentric homing task and return to a starting point. We then evaluated whether they could take shortcuts and navigate along never-traveled trajectories between four objects while blindfolded, thus demonstrating the ability to build a cognitive map. In the homing task, 96% of TD children, 84% of participants with DS and 44% of participants with WS were able to use path integration to return to their starting point consistently. In the cognitive mapping task, 64% of TD children and 74% of participants with DS were able to take shortcuts and use never-traveled trajectories, the hallmark of cognitive mapping ability. In contrast, only one of eighteen participants with WS demonstrated the ability to build a cognitive map. These findings are consistent with the view that hippocampus-dependent spatial learning is severely impacted in WS, whereas it is relatively preserved in DS.