The Effect of Upper Limb Loading During Partial Body Weight Support Treadmill Training in Children With Cerebral Palsy

Cerebral Palsy (CP) is a non-progressive neurodevelopmental disorder which affects the child's motor and sensory system, and consequently posture and walking. The underlying etiology is considered multifactorial, and no specific etiological factor has been blamed. While it may be seen in the prenatal, neonatal, and postnatal period, prenatal factors account for 70 to 80 % of all cases. Although the incidence of cerebral palsy widely varies worldwide, it has been often estimated as 1.5 to 2.5/1000. While the prevalence in young people is as high as 74%. One of the characteristics of CP is gait abnormalities because of myasthenia, spasticity and impairment of movement. Children with CP have difficulties in activities, which severely affect the children's quality of life. There is no cure for CP. WHO considers limb movement function as the main rehabilitation goal. Walking capacity training of CP needs to be taken seriously. Physiotherapy is considered the core part of CP children rehabilitation due to the risk of neurosurgery and side effects of drug intervention.

Many of the gait deviations observed in neurologically impaired patient results from their inability to adequately bear weight through their affected lower extremities during the loading phase of the gait cycle. Treadmill walking with partial body weight support (PBWS) using a harness seems to address the problem. It allows even a patient with severe weakness of lower limb extensor muscles to go through the gait cycle because lower levels of muscle forces are needed to support the body mass compared with over ground walking. In addition, the harness provides a sense of secure to the patient who has fear of falling.

Partial body weight support (PBWS) systems have been widely used as an alternative therapeutic strategy for gait training in different populations, including individuals with stroke , Parkinson's disease , Spinal cord injury and children with cerebral palsy.

Some individual studies suggested that treadmill training with body weight support was superior to treadmill training alone. The addition of body weight support makes repetitive training far more feasible for a boarder range of clients and allows for more flexibility in terms of optimizing speed and training kinematic patterns for those with weakness of other impairments limiting their gait function by increasing safety and decreasing the physical work necessary by one of more therapists. Many studies showed the effectiveness of body weight support training on gait and gross motor function in the rehabilitation of CP.

The trunk plays a critical role in the organization of postural reaction. The primary contribution of the trunk muscles is to stabilize the spine and trunk, and this stabilization is essential for free and selective movements of the head and the extremities. Children with CP frequently show impaired trunk control, which can affect performance of activities of daily life such as sitting, reaching and walking. The trunk was described as a key segment in the organization of postural stabilization and orientation control.

Upper body movement during walking provide information about balance control and gait stability, and children with CP exhibit a general increase of upper body acceleration compared to typically developing (TD) children which present a progressive decrease of acceleration from pelvis to head. Also, it has been found that excessive arm swing significantly increases local dynamics stability of human gait. And children with CP appear to rely on 'guard' arm posture as a compensation strategy to maintain balance while walking compared to newly walking toddlers. Spasticity and associated movements are also important contributing factors. The hand position of children with unilateral CP has been found to be more elevated and anterior, and their upper arm was rotated more posterior than typically developing children. A study showed that facilitation of arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with CP. Using arm cycling exercise has been found as an effective method for improving both arm swing and leg angular displacements during gait of children with hemiplegic CP. Also, it has been found that bilateral upper extremity exercises has a positive effect on trunk performance and alignment in stroke patients. From all of this physiotherapists get to know the importance of involving the upper limbs in the rehabilitation program for children with CP to improve gait.

A study indicated that walking while moving hand weights through large range of motion provides a combined upper and lower body aerobic stimulus that is sufficient for endurance training for persons with poor to excellent levels of aerobic fitness. Other studies looked for the physiological effect of hand-held weights during walking in normal adults. However, according to our knowledge no studies looked for the effect of upper limb external weights on gait and trunk in children with cerebral palsy. The investigators expect that placing an external weight around the both wrists while walking on the treadmill with partial body weight support will improve trunk control and gait in ambulatory children with cerebral palsy. The purpose of this study is to investigate if adding upper limb external weights during gait training using PBWS can increase the walking endurance, speed and trunk control in ambulatory children with CP.

Objectives:

To look for the effect of upper limb loading with external weights during partial body weight support treadmill training on gait speed, gait endurance and trunk control.

Hypothesis:

Investigator's hypothesis is that loading the upper limb with 1 lb. external weights during partial body weight support treadmill training is more effective than partial body weight support treadmill training without loading of the upper limbs in improving gait speed, gait endurance and trunk control.

Trial Design:

Randomized control trial