Short-term memory (STM) constraints in children with specific language impairment (SLI): are there differences between receptive and expressive SLI?

PURPOSE

Specific language impairment (SLI) is assumed to be causally related to deficits in auditory short-term memory (STM). Although verbal STM deficits have been consistently found in SLI, the results of visual STM tests are inconsistent. Do these inconsistencies reflect different study populations of expressive SLI (ELI) and receptive-expressive SLI (R/ELI)?

METHOD

Twenty-one children (ages 6-11) with ELI, 21 with R/ELI, and 21 controls (CG) matched on age and nonverbal intelligence were retrospectively compared with regard to their visual and auditory STM.

RESULTS

ELI children and R/ELI children performed significantly poorer than the CG in auditory-verbal STM tests. On tests for visual STM (symbol sequences), the R/ELI children performed significantly poorer than the CG. For hand movements, children with R/ELI scored slightly poorer compared to both other groups but without reaching statistical significance. Correlation analyses showed significant associations between symbol sequences and receptive language measures. Regression analysis found that the scores of symbol sequences and digit sequences together accounted for 39% of the variance of the receptive language measures, whereas the scores for nonsense syllables accounted for 24% of the variance of the expressive language measures.

CONCLUSION

R/ELI children appear to have more complex STM deficits, as they showed visual STM constraints in addition to auditory STM constraints.