A temporal-based therapy for children with inconsistent phonological disorder: A case-series

Deficits in temporal auditory processing, and in particular higher gap detection thresholds have been reported in children with inconsistent phonological disorder (IPD). Here we hypothesized that providing these children with extra time for phoneme identification may in turn enhance their phonological planning abilities for production, and accordingly improve not only consistency but also accuracy of their speech. We designed and tested a new temporal-based therapy, inspired by Core Vocabulary Therapy and called it T-CVT, where we digitally lengthened formant transitions between phonemes of words used for therapy. This allowed to target both temporal auditory processing and word phonological planning. Four preschool Persian native children with IPD received T-CVT for eight weeks. We measured changes in speech consistency (% inconsistency) and accuracy (percentage of consonants correct PCC) to assess the effects of the intervention. Therapy significantly improved both consistency and accuracy of word production in the four children: % inconsistency decreased from 59% on average before therapy to 2% post-T-CVT, and PCC increased from 61% to 92% on average. Consistency and accuracy were furthermore maintained or even still improved at three-month follow-up (2% inconsistency and 99% PCC). Results in a nonword repetition task showed the generalization of these effects to non-treated material: % inconsistency for nonwords decreased from 67% to 10% post-therapy, and PCC increased from 63% to 90%. These preliminary findings support the efficacy of the T-CVT intervention for children with IPD who show temporal auditory processing deficits as reflected by higher gap detection thresholds.