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Moore K.1, Brink Y.2, Louw Q.1, Cockroft J.3
1Stellenbosch University, Faculty of Medicine & Health Sciences, Interdisciplinary Health Sciences, Division of Physiotherapy, Cape Town, South Africa, 2Stellenbosch University, Faculty of Medicine & Health Sciences, Interdisciplinary Health Siences, Division of Physiotherapy, Cape Town, South Africa, 3Stellenbosch University, Unit for Human Movement, Central Analytical Facility, Cape Town, South Africa
Background: Fetal Alcohol Spectrum Disorder (FASD) is a leading preventable cause of acquired developmental disabilities in children and affects more than one million South Africans. Motor function and dynamic postural stability (DPS) are impaired in children with FASD. To date no research has been conducted on DPS in South African children with FASD.
Purpose: DPS and joint kinematics during single leg hopping were described in nine-year-old children from three groups: two groups of typically developed children from an urban and rural setting (controls) and a group of children with FASD from a rural setting (cases). The study also determined whether any differences in DPS of children with FASD and typically developed children in rural and urban areas existed.
Methods: Children and parents gave informed consent to participate. Motion analysis systems and a pressure mat were used to describe 1) DPS in terms of centre of pressure (COP) parameters during the landing phase and spatiotemporal parameters during the movement phase and 2) joint kinematics i.e. hip, knee and ankle angles in the sagittal plane. The COP parameters included anteroposterior (AP) and mediolateral (ML) velocity and range of motion (ROM). The spatiotemporal parameters included stance and swing times and speed of the trial. Children wore inertial measuring units on the lower limbs and pelvis. They performed five consecutive single leg hops in 45cm squares and finally landed on a pressure mat to stabilise on one leg. The descriptive results are presented in median and ranges and differences between groups were determined by Kruskal-Wallis statistical tests.
Results: Fifty-six children participated, 14 children with FASD (cases), 14 rural controls and 28 urban controls. The urban controls had significantly longer stance and swing times (p 0.001) than the case and rural control groups. COP parameters were not significantly different between the groups, however the female case group displayed greater AP velocity and AP ROM values compared to both control groups. The case group hopped at a faster speed than both control groups. For joint kinematics, the case group displayed lesser peak knee flexion angles (42.15˚) than rural controls (53.03˚) and urban controls (53.12˚). The case group also had lesser peak plantarflexion angles (5.22˚), while rural and urban controls were 10.24˚ and 13.24˚ respectively.
Conclusion(s): The groups of children adopted different timing and movement strategies to complete the hopping task. The urban controls had longer contact with the ground and in the air, indicating they used increased hip and knee flexion and ankle plantarflexion to propel them higher, but not faster than the rural groups. The case group hopped in a more upright position, at a faster speed and had poorer DPS in the AP direction compared to control groups especially for the females.
Implications: Motor function and DPS are common impairments in children with FASD. Identifying what aspects underlie these impairments through objective measurement methods may assist in the development of evidence-based physiotherapy treatments for these children. This is the first study of its kind in South Africa and further research is warranted.
Funding acknowledgements: The study was funded by the National Research Foundation (NRF) and Stellenbosch University.
Topic: Human movement analysis
Ethics approval: Approved by the Human Research Ethics Committee at Stellenbosch University (S15/09/207) and the Western Cape Education Department.
All authors, affiliations and abstracts have been published as submitted.
