Longitudinal development of gross motor function among Dutch children and young adults with cerebral palsy: an investigation of motor growth curves.
OBJECTIVE
The aim of this study was to describe patterns for gross motor development by level of severity in a Dutch population of individuals with cerebral palsy (CP).


METHODS
This longitudinal study included 423 individuals (260 males, 163 females) with CP. The mean age at baseline was 9 years 6 months (SD 6y 2mo, range 1-22y). The level of severity of CP among participants, according to the Gross Motor Function Classification System (GMFCS), was 50% level I, 13% level II, 14% level III, 13% level IV, and 10% level V. Participants had been assessed up to four times with the Gross Motor Function Measure (GMFM-66) at 1- or 2-year intervals between 2002 and 2009. Data were analysed using non-linear mixed effects modelling. For each GMFCS level, patterns were created by contrasting a stable limit model (SLM) with a peak and decline model (PDM), followed by estimating limits and rates of gross motor development.


RESULTS
The SLM showed a better fit for all GMFCS levels than the PDM. Within the SLM, significant differences between GMFCS levels were found for both the limits (higher values for lower GMFCS levels) and the rates (higher values for GMFCS levels I-II vs level IV and for GMFCS levels I-IV vs level V) of gross motor development.


CONCLUSIONS
The results validate the existence of five distinct patterns for gross motor development by level of severity of CP.
Rudolf Magnus Institute of Neuroscience and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and Rehabilitation Center De Hoogstraat, Utrecht, The Netherlands. d.smits@dehoogstraat.nl
Dirk-Wouter
DW
Smits
Jan Willem
JW
Gorter
Steven E
SE
Hanna
Annet J
AJ
Dallmeijer
Mirjam
M
van Eck
Marij E
ME
Roebroeck
Rimke C
RC
Vos
Marjolijn
M
Ketelaar
D000293:Adolescent; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009048:Motor Skills; D009069:Movement Disorders / Q000453:epidemiology / Q000503:physiopathology*; D009426:Netherlands / Q000453:epidemiology; D011597:Psychomotor Performance; D012720:Severity of Illness Index; D055815:Young Adult