Visuo-Spatial Construction: Task Specific Performance in Children with Fragile X Syndrome and Autism

Background:

It is well documented that individuals with autism (ASD) are relatively spared in tasks that require visuo-spatial construction abilities. However, research has found the opposite pattern in individuals with fragile X syndrome (FXS). The differences in visuo-spatial construction tasks between these two groups are apparent despite other documented similarities in their cognitive profile, such as deficits in executive function.

Objectives:

The current study employs the Navon task to investigate the visuo-spatial construction abilities in these two groups of children.

Methods:

A FXS group (21 children), a FXS group of 19 children that also fitted the criteria for ASD (AFXS), a group of 20 high functioning autistic children (HFA), 20 low functioning autistic children (LFA) and 80 typically developing children (TYP) took part in the study. Two construction Navon tasks were designed; one in which the children copied the stimuli by drawing it and one where the participants copied the stimuli by placing magnet cut-outs onto a white board.

Results:

For the drawing tasks, the main predictor of performance for the HFA was chronological age. However, non-verbal mental age predicted the performance of the LFA group. The performance of both FXS groups’ indicated that they depended mostly on verbal mental age. The results for the magnet task indicated that HFA and LFA performance was reliant on non- verbal and verbal mental age. However, verbal mental age still predicted the outcome from the two FXS groups.

Conclusions:

The results imply that both versions of the Navon task assessed different aspects of visuo-spatial construction as the participants employed different methods to complete the tasks. These findings indicate that a similar outcome in performance does not necessarily mean the tasks are completed via the same cognitive pathways.