Effects of timing parameter changes on the gait of functional electrical stimulation users with drop foot.

INTRODUCTION: Functional electrical stimulation uses clinician-set parameters to modify stimulation. This study aimed to investigate whether timing parameters in the ODFS Pace functional electrical stimulation device have an effect on the gait of the general population of functional electrical stimulation users who have a foot drop. METHODS: Twelve functional electrical stimulation users with foot drop resulting from upper motor neurone disorders were recruited from the functional electrical stimulation Service in Leeds, UK. A crossover trial design was used, comparing adjusted values of rising ramp, delay and extension. Instrumented gait analysis was carried out to measure ankle dorsiflexion during the swing phase of gait, foot clearance from the ground, and speed of ankle plantarflexion at initial contact. The effect of timing parameters on gait kinematics was studied. RESULTS: No statistically significant effects on the measured parts of gait were found for any of the timing parameters. Trends were identified in average mid-swing ground clearance and dorsiflexion associated with the delay and rising ramp timing parameters. CONCLUSIONS: Further work in this area should use larger numbers of participants. Based on these results, the effects of ramping and delay would be of particular interest for further study.

The dependency of air caloric stimulus effectiveness on delivery tip characteristics.

This brief study investigates the extent and origin of the apparent dependency of air delivery speculum size on the effectiveness of air used as a stimulus in the bi-thermal caloric test, using water as a reference stimulus. Eleven normal volunteers served as subjects. Six caloric stimulus delivery conditions included air with two speculum sizes, speculum only and with a rubber tube extension, and water. The resulting nystagmus was used as an index of stimulus efficiency. The effectiveness of the air stimulus was found to be dependent on the diameter of the speculum used for air delivery. The narrower speculum generated nystagmus that was typically twice that generated by the wider speculum. Users of air caloric equipment whose design includes a speculum that influences the effectiveness of the stimulus should be aware of this dependency and ensure their clinical interpretation of results is made with reference to appropriate normative data.