Developmental trajectories of receptive and expressive communication in children and young adults with cerebral palsy

Aim: The aim of this study was to determine the developmental trajectories of expressive (speech) and receptive (spoken and written language) communication by type of motor disorder and intellectual disability in individuals with cerebral palsy (CP). Method: The development of 418 participants (261 males, 157 females; mean age 9y 6mo [SD 6y 2mo], range 1-24y; Gross Motor Function Classification System (GMFCS) level I [n=206], II [n=57], III [n=59], IV [n=54], V [n=42]) was followed for 2 to 4 years in a longitudinal study. Communication performance was measured using the Vineland Adaptive Behavior Scales. The type of motor disorder was differentiated by type of CP as unilateral spastic (USCP, n=161), bilateral spastic (BSCP, n=202), and non-spastic (NSCP, n=55), while intellectual disability was determined by IQ or school type (regular or special). A multilevel analysis was then used to model the developmental trajectories. Results: The most favourable development of expressive communication was seen in USCP (vs BSCP β [SE]-2.74 [1.06], NSCP β [SE]-2.67 [1.44]). The difference between the development trajectory levels of children with and without intellectual disability was smaller for children with USCP than for those with BSCP and NSCP. For receptive communication, the most favourable development was found for all children with USCP and for BSCP or NSCP without intellectual disability (vs intellectual disability β [SE]-4.00 [1.16]). Development of written language was most favourable for children without intellectual disability (vs intellectual disability β [SE]-23.11 [2.85]). Interpretation: The development of expressive communication was found to be most closely related to type of motor disorder, whereas the development of receptive communication was found to be most closely related to intellectual disability