Spectral Coefficient Analyses of Word-Initial Stop Consonant Productions Suggest Similar Anticipatory Coarticulation for Stuttering and Nonstuttering Adults.

The sample was small, with 8 adults who stutter and 8 adults who do not stutter, so a subtle group difference could have been missed. The study tested only fluent single-word productions of /t/ before three vowels, not dysfluent speech, other consonants, sentences, or narratives. The recordings were originally made for an auditory feedback study, and only baseline trials were analyzed. Two adults who stutter had one unilateral 4000 Hz hearing threshold at 40 dB HL, so hearing was not identical across all participants. Stuttering severity ranged from very mild to very severe, and the paper does not say whether severity affected the acoustic results. The researchers deliberately used a loose statistical cutoff to look for any stuttering versus nonstuttering difference, so positive vowel and window effects should be read with that choice in mind. No treatment was tested, so the study cannot support therapy efficacy.

The supplied publication types indicate NIH extramural and non-U.S. government research support. The supplied article text does not include an author conflict of interest statement.

Do not conclude that stuttering speech motor control is normal. The null result applies only to perceptually fluent /t/ productions before three vowels in single words by 8 adults who stutter, and it does not test dysfluent speech, other sounds, sentences, or therapy outcomes.