| Cerebral Palsy (CP) is a developmental motor disorder and dysarthria is a predominant speech disorder in CP. However, speech characteristics and developmental speech patterns remain unknown in young children with CP. To examine these, two sub studies were conducted; a cross sectional study (Study 1) and a longitudinal study (Study 2).;In Study 1, to examine speech characteristics, 22 acoustic variables reflecting different speech subsystems were analyzed in 22 children with CP at an average age of 67 months and were compared to data from age-matched typically developing children. In addition, a speech intelligibility predictor model was tested with obtained speech acoustic and intelligibility data. In Study 2, to investigate speech developmental patterns, 13 speech acoustic and intelligibility variables were analyzed in young children with CP who were assigned to operationally defined severity groups over four longitudinal time sampling points spanning 18 months beginning at an average age of 50 months.;In Study 1, results showed that multiple acoustic variables reflecting different speech subsystems, but particularly in the articulatory domain, were different in children with dysarthria secondary to CP when compared to children with CP and no diagnosed speech disorders, and typically developing children. A significant speech intelligibility predictor model was obtained with acoustic variables reflecting different subsystems. Incremental R-squared analyses revealed that single contributors explained less than 8% of speech intelligibility variability in the model. In Study 2, results showed that there were significant differences in longitudinal patterns of change in acoustic variables according to severity group. Particularly, children in the severe group showed distinctively different longitudinal changes in vowel space and duration compared to the less impaired children with CP. At single time sampling points, vowel space and duration were significantly different across severity groups.;These findings suggest that (1) children with dysarthria secondary to CP have multiple speech subsystems affected, particularly the articulatory domain; (2) a multiple speech subsystem variable model is more appropriate than a single variable model when investigating speech production-based predictors of speech intelligibility; and (3) different early communication intervention approaches are warranted for children based on the severity of their speech impairment. |
