Delayed non-word repetition according to rehearsal conditions in 6- to 7-year-old children

Objectives: Among memory strategies, the one most closely related to short-term memory is rehearsal strategy. This research aims to study the influences of rehearsal conditions on the phonological short-term memory of typically developing children. Methods: Forty children age 6 to 7 performed delayed non-word repetition (dNWR) tasks according to rehearsal conditions (vocal rehearsal, subvocal rehearsal, rehearsal suppression). The accuracy and error types of three dNWR tasks were analyzed. The relationships among speech perception, digit forward, expressive vocabulary, and dNWR performances by each rehearsal condition were examined. Results: The 6-year-old group showed higher performances in the order of vocal rehearsal, subvocal rehearsal, and rehearsal suppression, while the 7-year-old group showed no significant difference between vocal rehearsal subvocal rehearsal, showing a significance only between those two conditions and rehearsal suppression. In the 6-year-old group, a 'no response' was the most abundant error type in rehearsal suppression, but 'phoneme substitution' increased in rehearsal conditions. In the 7-year-old age group 'phoneme substitution' appeared most frequently of all error conditions. The variables with the most predictive power were digit forward in vocal rehearsal, speech perception in subvocal rehearsal, and speech perception and expressive vocabulary in rehearsal suppression, respectively. Conclusion: dNWR performances with rehearsals showed better results than those without rehearsals. Also, there was a difference according to age between vocal rehearsal and subvocal rehearsal.