Adults who stutter: responses to cognitive stress.

The purpose of this study was to investigate the effects of speed and cognitive stress on the articulatory coordination abilities of adults who stutter. Cardiovascular (heart rate, systolic blood pressure, and diastolic blood pressure), behavioral (dysfluencies, errors, speech rate, and response latency), and acoustic (word duration, vowel duration, consonant-vowel transition duration/extent, and formant center frequency) measures for nine stutterers and nine nonstutterers were collected during performance of the Stroop Color Word task, a well-established and highly stressful cognitive task. Significant differences were found between the two groups for heart rate, word duration, vowel duration, speech rate, and response latency. In addition, stutterers produced more dysfluencies under speed plus cognitive stress versus speed stress or a self-paced reading task. These findings demonstrate that the presence of cognitive stress resulted in greater temporal disruptions and more dysfluencies for stutterers than for nonstutterers. However, similar spatial impairments were not evident. The potential contributions of the Stroop paradigm to stuttering research as well as the need for further research on autonomic correlates of stuttering are also discussed.