Dynamic ankle-foot orthoses in children with spastic diplegia interview and experimental studies

Abstract: Dynamic ankle-foot orthosis (DAFO) is a thin supra malleolar orthosis used as a compliment to the total treatment program in children with cerebral palsy (CP) in order to facilitate function in sitting, standing and walking. The DAFO keeps the foot in a functional position and is said to provide the child with proprioceptive feedback for balance- and postural control. The aim of the present thesis was to explore how parents of children with spastic diplegia experience the use of DAFOs and to determine the effects of DAFOs in standing during a reaching movement, in relation to postural orientation, anticipatory- and compensatory postural adjustments, and the quality of the reaching movement. The parents of 15 children, aged 4-18 years, who had spastic diplegia and wore DAFOs were interviewed with a broad research question "How do you perceive that DAFO influence your child" and analysed with content analysis. Children with spastic diplegia, aged 5-12 years, (n=6 in studies II and IV and n=4 in study III) classified at level II-IV according to Gross Motor Function Classification System (GMFCS) and typically developing children (controls) (n=8 in study III and n=6 in study IV) in the same age-group performed a voluntary reaching movement towards a target while standing on force plates. This allowed for registration of forces, movement and muscle activity (EMG). Children with spastic diplegia used DAFOs and/or shoes during the experiment while controls used shoes only. The parents experienced that DAFOs with their stabilizing effect on the foot and ankle enabled postural control and alignment, which contributed to functional activities under more favourable physical conditions. Moreover, psychosocial aspects such as a feeling of security, safety and freedom were regarded by the parents as being as important as the physical effects. Our findings showed that children with more severe spastic diplegia applied their body weight in standing more evenly between the legs and improved extension of the knee using DAFOs compared to wearing shoes alone. To initiate the reaching movement, despite different support conditions, children with spastic diplegia wearing DAFOs, as well as the controls make use of anticipatory postural adjustments. Furthermore, during the acceleration and deceleration phase of the reaching movement, children with spastic diplegia make use of compensatory postural adjustments characterized by co-contraction of tibialis anterior (TA) and lateral gastrocnemius (LG) muscles bilaterally. The postural adjustments in the controls were characterized by increased TA activity on the reach side during the acceleration phase and increased LG activity on the non-reach side during the deceleration phase. Movement quality in reaching in children with spastic diplegia showed that coordination between upward and forward reach velocity differed regarding temporal phasing and amplitudes of velocity peaks compared to the controls. According to parents´ perceptions DAFOs can be regarded as a part of treatment that improves stability, balance and functional skills. Children with severe spastic diplegia wearing DAFOs can, in spite of different support conditions, practice standing with a more evenly distributed body weight on the feet. The practice of reaching movements while standing with DAFOs can promote motor learning of postural adjustments and thereby improve the ability to use the hands in daily activities.