Abstract
A common feature of cerebral palsy is persistent toe walking on the most affected side, which may result in an unstable gait and frequent falls. Results from current interventions, such as AFOs, plaster boots, botulinum, or surgery are mixed, with some being poorly tolerated and/or with only temporary results. An alternative intervention may be functional electrical stimulation (FES) in which (for this application) electrical pulses are applied to motor points through surface electrodes by a small, lightweight, external battery unit. The dynamic nature of FES may promote a more normal gait pattern and strengthen and re-educate the affected muscles. There are two apparently opposing approaches, with some studies reporting positive results from stimulating the anterior tibial muscles and studies reporting positive results from stimulating the calf muscles. Whilst both approaches have shown some encouraging results they fail to produce conclusive evidence as to which should be the treatment of choice or provide prescription guidelines for appropriate selection. The aim of this pilot study was to establish whether FES applied to the anterior tibial muscles can be used successfully to control toe walking in children with CP, building on the widely accepted model used in adults. In addition it was aimed at establishing any preconditions that need to be met. An ABA approach was used (A - non intervention; B - intervention) with each phase lasting three months, which allowed the treatment to continue for a greater period than previous studies. In terms of daily exposure, children used the device throughout their daily activities. Sufficient subjects were recruited for a statistical analysis. To control for the effects of other treatments existing therapeutic inputs continued, whilst making kinematic, kinetic, energy consumption, and clinical measurements to quantify changes. Data for over 2000 steps from ten children at six measurement sessions were recorded. Results suggest immediate orthotic and longer term therapeutic effects, as measured by the heel-toe interval, knee angle at foot contact, step and stride length, cycle time, speed, and energy consumption. Significance at the 0.05 level was reached for step and stride lengths, and speed. The effectiveness of the stimulation from the users’ point of view was assessed through a questionnaire, completed by the child and their parent or carer. A major weakness identified in the course of the study was a lack of sufficient subject numbers to allow greater statistical significance to be achieved. In addition, the lack of sufficient subjects did not allow the unambiguous identification of any sub-groups who may benefit more or less than others. Improved equipment may also have made possible a better estimate of heel-toe intervals, which appears to be potentially useful outcome measure. Future work planned includes a similar study of calf muscle stimulation and improvements to the stimulator equipment.