Kinematic Characteristics of Speaking Rate in Individuals with Cerebral Palsy: A Preliminary Study

Many individuals with cerebral palsy (CP) have a slower speaking rate compared with their typically developing peers. Previous studies examining age-related changes in speaking rate in typical development suggest that (1) cognitive and linguistic processing increases account for most of these changes, and (2) changes to linguistic task demands affect the articulatory strategies used to produce the target stimuli (e.g., truncating movements for tasks with fewer linguistic demands). The purpose of this study was to determine the relations between linguistic and physiologic factors in individuals with CP to better understand how the pathophysiology of CP affects speech production in these individuals. Four participants with CP and 38 age-matched peers were asked to complete a diadochokinetic (DDK) task, a vowel-consonant-vowel syllable repetition task, and a sentence repetition task. Speaking rate for the tasks and lower lip maximum movement speed, range of movement, and duration of the closing and opening gestures common to each task were measured. In general, participants with CP have reduced speaking rates compared with their typically developing peers despite increased movement speeds. In both groups, linguistic task effects were observed; higher linguistic demands resulted in slower speaking rates and higher movement speeds. Range of movement was greater for participants with CP than their typically developing peers and may have contributed to the observed decreased speaking rates in individuals with CP.