Error Characteristics Lend Specificity to Nonword Repetition Performance in Children Who Stutter With and Without Concomitant Disorders

Purpose: In our earlier study, we found that overall accuracy on nonword repe-tition (NWR) lacked the specificity to differentiate among groups of children who stutter (CWS) with and without concomitant speech sound and/or language dis-orders and children who do not stutter (CWNS). The aim of this study was to determine whether NWR error characteristics distinguish these groups of chil-dren with different speech sound production and language abilities yielding insight into the deficits underlying poorer performance. Method: Participants were 141 children (88 CWS, 53 CWNS). CWS were divided into subgroups based on the presence or absence of concomitant speech sound and language disorders. Children completed an NWR task composed of one-to four-syllable nonwords. Error types included omissions, substitutions, and migrations. Error location was documented across the syllables of the longest, four-syllable non -words and within each syllable (onset, nucleus, and coda) for all nonwords. Results: We found that error patterns characterized groups' NWR performance. Specifically, CWS groups made more errors on syllable onsets, more errors on the first and fourth syllable of the four-syllable nonwords, and more substitution errors than CWNS. CWS with concomitant speech sound and/or language dis-orders made more omission errors than CWNS and CWS with typical speech sound and language abilities. CWS with both a speech sound and language disorder made more migration errors than all other groups. Conclusions: Using a data-driven framework derived from prior empirical inves-tigations of NWR errors, this study demonstrated that error characteristics enhance the specificity of NWR by distinguishing groups of CWS with and with-out concomitant speech sound and language deficits. These error patterns also provide a window into the processes underlying NWR performance in CWS.