Decreased sensitivity to changing durational parameters of syllable sequences in people who stutter

Stuttering is a disorder that affects the coordination of complex sequencing mechanisms that define the temporal layout of speech. However, classical motor areas of the brain, responsible for the sequencing of articulatory aspects in speech production also process non-verbal and even non-motor temporal information. This configuration suggests that perceptual temporal processing capacities may factor into the symptom profile of various motor disorders. We investigated perceptual sensitivity for changing temporal parameters of sequentially presented consonant-vowel-consonant syllables in people who stutter (PWS) and matched controls. Changes were durational contrasts (short vs. long) of the whole syllable and/or the vocalic nucleus. Analyses focused on sensitivity indices (d'), response times, response time variability, and co-variation of these variables with offline measures of cognitive performance. Results indicate lower sensitivity for durational contrasts and longer and more variable response times for long vowels in the PWS group, pointing towards subtle perceptual verbal temporal processing differences.