Efficacy and Cross-Domain Effects of a Morphosyntax and a Phonology Intervention

The purpose of this study was three-fold: (a) to determine the efficacy of a morphosyntax and a phonology intervention against a no-treatment control group, (b) to assess the effects of those interventions on the non-targeted domain, and (c) to evaluate sequence effects when children receive both interventions.

Twenty preschoolers with impairments in both morphosyntax and phonology were assigned randomly to an intervention of two 12-week blocks beginning with either a block of phonology first (n = 10) or a block of morphosyntax first (n = 10). Data were collected at pretreatment, after the first intervention block, and posttreatment. For a control group of 7 children, data were collected at the beginning and end of a time period equivalent to one intervention block. Changes in a finite morpheme composite and target/generalization phoneme composite were assessed.

In comparison to the control group, both interventions were effective at a statistically significant level in facilitating improvement in the target domain after 12 weeks. The morphosyntax intervention led to cross-domain change in phonology that was similar to that achieved by the phonology intervention. The morphosyntax first sequence also led to slightly better overall morphosyntactic performance.

Clinically, results suggest targeting morphosyntax first, followed by phonology, if using a block intervention sequence for children with concomitant morphosyntactic and phonological impairments.