Visuo-spatial STM impairment link to a serial order component deficit in children with Velocardiofacial syndrome

Some previous studies showed that verbal short-term memory (STM) is better preserved than visuospatial STM in the velocardiofacial syndrome (VCFS), a neurodevelopmental disorder resulting from a 22q11.2 deletion. This deficit is generally assigned to a more global visuospatial skills deficit. However, for verbal STM, previous study suggested a specific deficit in the serial order component, processing considered as independent of modalities.
In this study we proposed to explore the serial order component in visuospatial STM by contrasting simultaneous vs. sequential presentation of stimuli to maintain in children with VCFS, in order to see in what extent the deficit is global and resulting from visuospatial deficit or whether this deficit is specific to the serial order component. We tested a group of 27 children and adolescents with VCFS to a control group, matched on verbal IQ performance estimated. The VCFS group showed impaired performance on the sequential configuration but similar performance on the simultaneous condition. These results support the idea of an amodal serial order component in STM. The implication of serial order STM deficits on numerical cognition will be discussed.