Introduction
Motor difficulties in preterm children may be observable at an early age,1,2 and even in the absence of severe impairment, 30 to 50% of preterm and/or low-weight children have mild motor difficulties.3 It is well known that cerebral palsy (CP) and other neurological sequelae due to prematurity are associated poor motor development.1,4,5 However, many of preterm children do not have any neurological impairment and may demonstrate more subtle motor difficulties that can later be identified as Developmental Coordination Disorder (DCD).6 Further, these mild difficulties may be overlooked by parents and clinicians, which may lead to a late diagnosis and a delayed necessary intervention such as physical therapy.
Developmental coordination disorder (DCD) is an impairment of motor skills that significantly interferes with the child’s performance in their daily activities, academic performance, and leisure activities in otherwise healthy children.7 A DCD diagnosis is based on the Diagnostic and Statistical Manual of Mental Disorders – 5th edition (DSM-5). 7 The DSM-5 establishes four criteria for diagnosis: 1) Learning and execution of coordinated motor skills are below the expected level for age, given opportunities for skill learning; 2) Motor skill difficulties significantly interfere with activities of daily living and impact academic/school productivity, pre-vocational and vocational activities, leisure and play; 3) Onset of delays is observed in the early developmental period; and 4) Motor skill difficulties are not better explained by intellectual delay, visual impairment or other neurological conditions that affect movement.7
It is estimated that around 6% of the world’s school-age population is meet criteria for DCD.8,9 However, in the preterm population, the reported prevalence varies owing to different assessment tools, cut-off criteria, and the preterm population. There are two systematic reviews indicating that prematurity increases the risks of DCD.10,11 The first one evaluated 11 studies and demonstrated that premature children are at risk three to four times higher than the general population. The pooled estimation for DCD was 19% and 40.5% depending on the cut-off point used for diagnosis.10 The second one evaluated 16 studies and pointed out that preterm infants are six to eight times more likely to have DCD.11
However, the two systematic reviews10,11 are from more than 10 years ago, and they did not assess the prevalence of DCD according to gestational age. Besides, none included studies from Low-Moderate Income Countries (LMIC), and none compared preterm children with different gestational ages. All these factors combined justify conducting a new study with more current articles and a more comprehensive global sample and expanding the previous group comparisons to include gestational age. Therefore, we established four aims for this systematic review and meta-analysis: 1) to investigate the prevalence of developmental coordination disorder in individuals born preterm; 2) to investigate the prevalence of developmental coordination disorder in individuals born preterm according to gestational age; 3) to investigate the prevalence of DCD in individuals born preterm according to different assessments cut-offs; 4) to investigate the prevalence of developmental coordination disorder in individuals born preterm compared to full terms. The hypothesis is that children born preterm will have higher prevalence of DCD than children born at term and this prevalence will be even higher in those born extremely preterm. Also, studies will present different criteria to identify DCD and varied prevalence rates.