High variability of individual longitudinal motor performance over five years in very preterm infants.
OBJECTIVE
To determine longitudinal motor performance in very preterm (VPT) infants from 6 months to 5 years of age for the entire cohort of infants, according to gender and gestational age and at the individual level.


METHODS
Single-center, prospective longitudinal study of 201 VPT infants (106 boys) without severe impairments.


RESULTS
Motor performance was assessed with the Bayley Scales of Infant Development (BSID-II-MS: 6, 12, 24 months) and the Movement Assessment Battery for Children (MABC-2-NL: 5 years).


RESULTS
At 6, 12, and 24 months and then at 5 years, 77%, 80%, 48%, and 22% of the infants, respectively, showed delayed motor performance (<-1SD). At 5 years, girls performed significantly better than boys in manual dexterity and balance. MIXED MODEL ANALYSES: that examined interactions between time and gender and time and gestational age, revealed no significant interactions. The variance at child level was 29%. Linear mixed model analysis revealed that mean z-scores of -1.46 at 6 months of age declined significantly to -0.52 at 5 years. Individual longitudinal motor performance showed high variability.


CONCLUSIONS
Longitudinal motor performance improved almost 1 SD over five years. However, the variability of individual longitudinal motor performance hampers evaluation in clinical care and research.
Radboud University Medical Center, Amalia Children's Hospital, Department of Rehabilitation, Pediatric Physical Therapy, Nijmegen, The Netherlands. Electronic address: anjo.janssen@radboudumc.nl.
Anjo J W M
AJWM
Janssen
Radboud University Medical Center, Radboud Institute for Health Sciences, Scientific Institute for Quality of Healthcare, Nijmegen, The Netherlands. Electronic address: rob.oostendorp@planet.nl.
Rob A B
RAB
Oostendorp
Radboud University Medical Center, Radboud Institute for Health Sciences, Scientific Institute for Quality of Healthcare, Nijmegen, The Netherlands. Electronic address: reinier.akkermans@radboudumc.nl.
Reinier P
RP
Akkermans
Radboud University Medical Center, Amalia Children's Hospital, Department of Pediatrics, Nijmegen, The Netherlands. Electronic address: Katerina.steiner@radboudumc.nl.
Katerina
K
Steiner
Radboud University Medical Center, Amalia Children's Hospital, Department of Pediatrics, Nijmegen, The Netherlands. Electronic address: l.a.a.kollee@glazenkamp.net.
Louis A A
LAA
Kollée
Radboud University Medical Center, Amalia Children's Hospital, Department of Rehabilitation, Pediatric Physical Therapy, Nijmegen, The Netherlands; Radboud University Medical Center, Radboud Institute for Health Sciences, Scientific Institute for Quality of Healthcare, Nijmegen, The Netherlands. Electronic address: Ria.Nijhuis-vanderSanden@radboudumc.nl.
Maria W G
MWG
Nijhuis-van der Sanden
D002657:Child Development; D002675:Child, Preschool; D005260:Female; D005865:Gestational Age; D006225:Hand; D006801:Humans; D007206:Individuality; D007223:Infant; D062071:Infant, Extremely Premature; D007234:Infant, Premature; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D009048:Motor Skills; D004856:Postural Balance; D011446:Prospective Studies; D012737:Sex Factors
Longitudinal studies; Motor skills; Premature birth