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Background: Two reasons may explain the discrepant findings regarding declarative memory in developmental language disorder (DLD) in the literature. First, standardized tests are one of the primary tools used to assess declarative memory in previous studies. It is possible they are not sensitive enough to subtle memory impairment. Second, the system underlying declarative memory is complex, and thus results may vary depending on the types of encoding and retrieval processes measured (e.g., item specific or relational) and/or task demands (e.g., recall or recognition during memory retrieval). Aims: To adopt an experimental paradigm to examine episodic memory functioning in adolescents with and without DLD, with the focus on memory recognition of item-specific and relational information. Methods & Procedures: Two groups of adolescents, one with DLD (n = 23; mean age = 16.73 years) and the other without (n = 23; mean age = 16.75 years), participated in the study. The Relational and Item-Specific Encoding (RISE) paradigm was used to assess the effect of different encoding processes on episodic memory retrieval in DLD. The advantage of using the RISE task is that both item-specific and relational encoding/retrieval can be examined within the same learning paradigm. Outcomes & Results: Adolescents with DLD and those with typical language development showed comparable engagement during the encoding phase. The DLD group showed significantly poorer item recognition than the comparison group. Associative recognition was not significantly different between the two groups; however, there was a non-significant trend for to be poorer in the DLD group than in the comparison group, suggesting a possible impairment in associative recognition in individuals with DLD, but to a lesser magnitude. Conclusions & Implications: These results indicate that adolescents with DLD have difficulty with episodic memory retrieval when stimuli are encoded and retrieved without support from contextual information. Associative recognition is relatively less affected than item recognition in adolescents with DLD.

The aim of the current study was to examine different aspects of procedural memory in young adults who varied with regard to their language abilities. We selected a sample of procedural memory tasks, each of which represented a unique type of procedural learning, and has been linked, at least partially, to the functionality of the corticostriatal system. The findings showed that variance in language abilities is associated with performance on different domains of procedural memory, including the motor domain (as shown in the pursuit rotor task), the cognitive domain (as shown in the weather prediction task), and the linguistic domain (as shown in the nonword repetition priming task). These results implicate the corticostriatal system in individual differences in language.

The aim of the study was to examine reinforcement learning (RL) in young adults with developmental language impairment (DLI) within the context of a neurocomputational model of the basal ganglia-dopamine system (Frank, Seeberger, & O'Reilly, 2004). Two groups of young adults, one with DLI and the other without, were recruited. A probabilistic selection task was used to assess how participants implicitly extracted reinforcement history from the environment based on probabilistic positive/negative feedback. The findings showed impaired RL in individuals with DLI, indicating an altered gating function of the striatum in testing. However, they exploited similar learning strategies as comparison participants at the beginning of training, reflecting relatively intact functions of the prefrontal cortex to rapidly update reinforcement information. Within the context of Frank's model, these results can be interpreted as evidence for alterations in the basal ganglia of individuals with DLI. (Contains 1 table and 5 figures.)

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The aim was to explore whether genetic variation in the dopaminergic system is associated with procedural learning and the corticostriatal pathways in individuals with developmental language impairment (DLI). We viewed these two systems as endophenotypes and hypothesised that they would be more sensitive indicators of genetic effects than the language phenotype itself. Thus, we genotyped two single nucleotide polymorphisms in DRD2/ANKK1, and tested for their associations to the language phenotype and the endophenotypes. Results showed that individuals with DLI revealed poor procedural learning abilities and abnormal structures of the basal ganglia. Genetic variation in DRD2/ANKK1 was associated with procedural learning and microstructural differences of the caudate nucleus. The association of the language phenotype with DRD2/ANKK1 polymorphisms was non-significant, but the language phenotype was significantly associated with the endophenotypes. We suggest procedural learning and the corticostriatal pathways as effective endophenotypes to aid molecular genetic studies searching for genes predisposing to DLI. [ABSTRACT FROM PUBLISHER]