Recent studies on specific language impairment (SLI) have suggested that language deficits are directly associated with poor procedural learning abilities (Kemény & Lukács, 2010; Lum, Gelgec, & Conti-Ramsden, 2009; Tomblin, Mainela-Arnold, & Zang, 2007; Ullman & Pierpont, 2005). Findings from our previous work (Gabriel, Stefaniak, Maillart, Schmitz, & Meulemans., submitted) are contrary to this hypothesis; we found that children with SLI were able to learn 8 element long sequences as fast and as accurately as children with normal language NL on a serial reaction time (SRT) task. A probabilistic rather than a deterministic SRT paradigm was used in the current study to explore procedural learning in children with SLI in order to mimic real conditions of language learning. Fifteen children with or without SLI were compared on an SRT task including a probabilistic 8 element long sequence. Results show that children with SLI were able to learn this sequence as fast and as accurately as children with NL, and that similar sequence-specific learning was observed in both groups. These results are novel and suggest that children with SLI do not display global procedural system deficits.

According to the procedural deficit hypothesis (PDH), abnormal development in the procedural memory system could account for the language deficits observed in specific language impairment (SLI). Recent studies have supported this hypothesis by using a serial reaction time (SRT) task, during which a slower learning rate is observed in children with SLI compared to controls. Recently, we obtained contrasting results, demonstrating that children with SLI were able to learn a sequence as quickly and as accurately as controls. These discrepancies could be related to differences in the statistical structure of the SRT sequence between these studies. The aim of this study was to further assess, in a group of 21 children with SLI, the PDH with second-order conditional sequences, which are more difficult to learn than those used in previous studies. Our results show that children with SLI had impaired procedural memory, as evidenced by both longer reaction times and no sign of sequencespecific learning in comparison with typically developing controls. These results are consistent with the PDH proposed by Ullman and Pierpont (2005) and suggest that procedural sequence-learning in SLI children depends on the complexity of the to-be-learned sequence.

Purpose According to the procedural deficit hypothesis (PDH), difficulties in the procedural learning (PL) system may contribute to the language difficulties observed in children with specific language impairment (SLI). Method Fifteen children with SLI and their typically developing (TD) peers were compared on visual PL tasks—specifically, deterministic serial reaction time (SRT) tasks. In the first experiment, children with SLI and their TD peers performed the classical SRT task using a keyboard as response mode. In the second experiment, they performed the same SRT task but gave their responses through a touchscreen (instead of a keyboard) to reduce the motor and cognitive demands of the task. Results Although in Experiment 1 , children with SLI demonstrated learning, they were slower and made more errors than did their TD peers. Nevertheless, these relative weaknesses disappeared when the nature of the response mode changed ( Experiment 2 ). Conclusions In this study, the authors report that children with SLI may exhibit sequential learning. Moreover, the generally slower reaction times observed in previous deterministic SRT studies may be explained by the response mode used. Thus, our findings are not consistent with the predictions of the PDH, and these findings suggest that language impairments in SLI are not sustained by poor procedural learning abilities.

It has been suggested that the language problems encountered in specific language impairment (SLI) arise from basal ganglia abnormalities that lead to impaired procedural memory. However, recent serial reaction time (SRT) studies did not reveal any differences between the SLI and typically developing (TD) groups on the measures of procedural memory linked to visual sequence learning. In this paper, 16 children with and without SLI were compared on two versions of SRT tasks: a visual task and an auditory one. The results showed that children with SLI were as fast as their TD peers in both modalities. All of the children obtained similar specific sequence learning indices, indicating that they were able to detect regularities in both modalities. Although children with SLI were as accurate as their TD peers for the visual SRT task, they made more errors than their TD peers in auditory SRT conditions. The results indicate that, in relation to procedural memory, the core of the impairment in SLI is not linked to difficulties in the detection of regularities. We argue that when children with SLI present some difficulties, the children's weaknesses might depend on the type of processing involved (e.g., tasks involving auditory sequences).Children with specific language impairment (SLI) encounter difficulties in language acquisition, despite normal intelligence, normal vision and hearing, the absence of neurological impairment, and even growing up in a supportive communicative environment. Several areas of language may be affected, including vocabulary, morphosyntax, discourse, written language, and social language (for reviews, see Leonard, 1998;and Schwartz, 2009). Nevertheless, some researchers question the relevance of the term specific language impairment (Ors, 2002).