The influence of hippotherapy on trunk muscle activation in a child with cerebral palsy: a case study

Abstract

Introduction: Hippotherapy is a means of rehabilitation that uses the horse and the environment as therapeutic tools for the treatment of people with disabilities, including Cerebral Palsy (CP). The movement produced by the horse is highly complex and promotes, in the mounted person, three-dimensional displacements. The horse has swaying patterns similar to human walking, encouraging muscle activity in people with CP or other health conditions. The association of voluntary movements of the upper limbs to this range of stimuli can further increase the challenge of the systems involved in postural control to maintain balance. However, although there is evidence of the benefits of Hippotherapy on the motor control of people with CP, a characterization of the influence of the horse's step on the activation of the trunk muscles is not available in the literature. Objective: to investigate the influence of the horse's step on the activity pattern of the trunk muscles in a child with CP. Methods: A 10-year-old female child diagnosed with diplegic bilateral spastic CP, level I of the Gross Motor Function Classification System (GMFCS) was evaluated. A pair of bipolar surface electrodes were placed on the longissimus muscle of the right dorsum to collect the surface electromyogram (EMG) and estimate the level of muscle activity in the following tasks: i) remain seated in a chair with the feet supported (task control) and ii) remain seated on the moving horse. The movement of bilateral shoulder flexion at 180º was performed in each task, with a duration of 10s. Results: From the visual inspection of the EMG signals, a relatively high and prolonged signal amplitude was observed during the entire horse sitting condition compared to the chair sitting condition. In a quantitative analysis, the root mean square (RMS) amplitude of the EMG signal was higher in the sitting-on-horse posture than in the sitting-in-chair task, indicating a higher level of muscle activity of the longissimus dorsi when the child was submitted to hippotherapy. (horse step). Conclusion: These results indicate that Hippotherapy can be used to stimulate the paravertebral muscles in children with CP.