Examination of Stuttering by D-C Model: From A Case Study of A Monozygotic Disconcordant Twin

Abstract

We examined the mother-child speech relationship using a D-C Model (Demand-Capacity Model). The child is a monozygotic disconcordant twin. Speech rate was calculated as OSR (syllables/60 sec.), and length of utterance was calculated as MLU (segmental sentences/total utterances). The smaller the differences between OSR and MLU of the mother and those of the child, the more the demand and capacity are concordant, and the less we consider the child to be under a burden. In the first stage of treatment, the difference in MLU between the mother and child was large, but in the second and third phases, the mother's MLU decreased whereas the child's increased. In the first stage, in OSR both mother and child spoke fast and the child felt burdened; but in the second period the mother spoke slowly, under our guidance, and the child's speech rate decreased after the mother's change in speed. In both MLU and OSR, from the first through third phases the differences decreased, showing harmony between demand and capacity. The child's disfluency eventually disappeared, and we think there will be no problem of any increase in the difference between them in MLU or OSR in the follow-up sessions. © 1997, The Japan Society of Logopedics and Phoniatrics. All rights reserved.