Segmental and metrical complexity during non-word repetition in adults who stutter.

Non-word repetition is weaker for adults who stutter (AWS) compared to adults who do not stutter (AWNS) as phonological demands increase. However, non-word stimuli used in previous studies varied by length, but did not vary with regard to segmental or metrical complexity. The purpose of the present study was to examine the unique influence of these two distinct types of complexity on non-word repetition in AWS and AWNS via administration of the Test of Phonological Structure (TOPhS). Twenty-four adults (12 AWNS, 12 AWS) repeated 96 non-words within a soundproof booth immediately after auditory presentation. All 96 non-word targets included on the TOPhS were one to four syllables in length and ranked based on segmental complexity (simple, moderate and complex) and metrical complexity (simple, moderate and complex). No main effect of metrical complexity was detected between groups, and no differences in accuracy were observed for non-words with simple or moderate segmental complexity. However, AWS were significantly more likely to produce a phonemic error when repeating words with complex segmental structure than AWNS, irrespective of metrical complexity. Segmental complexity may contribute to the differences in phonological working memory in AWS when controlling for metrical complexity and length.