title: Correlation between the Gait Deviation Index and gross motor function (GMFCS level) in children with cerebral palsy.
abstract: OBJECTIVE
  The Gait Deviation Index (GDI) is a score derived from three-dimensional gait analysis (3DGA). The GDI provides a numerical value that expresses overall gait pathology (ranging from 0 to 100, where 100 indicates the absence of gait pathology). The aim of this study was to investigate the association between the GDI and different levels of gross motor function [defined as the Gross Motor Function Classification System (GMFCS)] and to explore if age, height, weight, gender and cerebral palsy (CP) subclass (bilateral and unilateral CP) exert any influence on the GDI in children with unilateral and bilateral spastic CP.
  
  
  METHODS
  We calculated the GDI of 109 children [73 % boys, mean age 9.7 years (standard deviation, SD 3.5)] with spastic CP, classified at GMFCS levels I, II and III. Twenty-three normally developing children were used as controls [61 % boys, mean age 9.9 years (SD 2.6)]. Multiple linear regression analysis was performed.
  
  
  RESULTS
  The mean GDI in the control group was 100 (SD 7.5). The mean GDI in the GMFCS level I group was 81 (SD 11), in the GMFCS level II group 71 (SD 11) and in the GMFCS level III group 60 (SD 9). Multiple linear regression analysis showed that gender, age and CP subclass had no significant correlation with the GDI, whereas height and weight had a slight impact.
  
  
  CONCLUSIONS
  This study showed a strong correlation between the GDI and GMFCS levels. The present data indicate that calculation of the GDI is a useful tool to characterise walking difficulties in children with spastic CP.
authors.affiliation: Bergen Gait Laboratory, Haukeland University Hospital, Helse Bergen HF, Postboks 1400, 5021, Bergen, Norway. merete.andersen.malt@helse-bergen.no.|Department of Physiotherapy, Haukeland University Hospital, Helse Bergen HF, Postboks 1400, 5021, Bergen, Norway. merete.andersen.malt@helse-bergen.no.
authors.forename: Merete A
authors.initials: MA
authors.lastname: Malt
authors.affiliation: Bergen Gait Laboratory, Haukeland University Hospital, Helse Bergen HF, Postboks 1400, 5021, Bergen, Norway. aanen.aarli@helse-bergen.no.|Department of Paediatrics and Regional Centre of Habilitation and Rehabilitation in Western Norway, Haukeland University Hospital, Bergen, Norway. aanen.aarli@helse-bergen.no.
authors.forename: Ånen
authors.initials: Å
authors.lastname: Aarli
authors.affiliation: Department of Global Public Health Care and Primary Care, The University of Bergen, Postboks 7800, 5020, Bergen, Norway. Bard.Bogen@igs.uib.no.
authors.forename: Bård
authors.initials: B
authors.lastname: Bogen
authors.affiliation: Bergen Gait Laboratory, Haukeland University Hospital, Helse Bergen HF, Postboks 1400, 5021, Bergen, Norway. jonas.meling.fevang@helse-bergen.no.|Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway. jonas.meling.fevang@helse-bergen.no.
authors.forename: Jonas M
authors.initials: JM
authors.lastname: Fevang
keywords: Cerebral palsy; Gait; Gait Deviation Index; Gross Motor Function Classification System (GMFCS); Three-dimensional gait analysis