Description
Specific Language Impairment (SLI) is a neurodevelopmental disorder which interferes with language expression and processing, but children with SLI show no obvious physical or neurological basis for such deficits. Numerous hypotheses have been proposed to explain its origins. One recent approach proposes that individuals with SLI have a deficit to procedural learning. Ullman's Procedural Deficit Hypothesis (PDH) is based on anatomical differences between individuals with SLI and typically developing controls in the subcortical-cortical circuit underlying procedural learning and memory. The PDH predicts that individuals with SLI will have difficulty with any task recruiting this circuit. Previous studies have focused on difficulties that children with SLI have with learning target sequences. Based on this hypothesis and on the functions associated with the procedural learning circuit, children with SLI can be expected to also have difficulty generating new sequences. This study compares the sequence production abilities of 6-7 year olds with SLI to that of age-matched typically developing (TD) peers. Three tasks are used (picture arrangement, scripts, and biographic interviews) to explore how event sequencing, syllable sequences, and intonation may be impacted in SLI. Overall, children with SLI perform more poorly than TD children on all three tasks. They are less able to generate sequences of events, both nonverbally and verbally. They speak in shorter segments and at a slower rate in the biographic interviews. Finally, they do not use intonation comparably to TD children when communicating the end of a turn. The procedural deficit hypothesis may be able to account for the event and syllable sequencing results of this study, but cannot fully explain the intonation results. Further research is recommended to explore the relationships between sequence learning and sequence production and between verbal and nonverbal domains.
