Evaluation of a Novel Bionic Foot, AMPfoot 4+

Background: Evaluating the use of a novel motorized ankle prosthesis during walking and under dual task circumstances is an important step in product development.

Objective: To iteratively evaluate the effectiveness of a novel bionic foot, the Ankle Mimicking Prosthetic device 4+ (or AMPfoot 4+), during walking.

Study design: Case study (crossover) research design.

Methods: One male subject will conduct a baseline experimental trial with the current prosthetic device and several experimental trials with the AMPfoot 4+ to evaluate the effectiveness of the novel device and investigate the adaptation period. Prior to baseline experiments, a familiarization trial will be performed to determine intra-subject variability of the dual task. An experimental trial consists of 2 walking tasks, i.e. the 6-minute walk test (6MWT) and the 10-meter walk test. The 6MWT will be combined with a cognitive task, i.e. backwards counting, to create dual task circumstances. The outcome measurements for the dual task are the distance covered and the walking speed, heart rate (HR) (Polar), rating of perceived exertion (RPE), VO2 (Cosmed K5), electro-encephalography (EEG), electro-myography (EMG), electro-cardiography (ECG), electrodermal activity (/skin conductance),accuracy and total duration of the cognitive task, BodyMedia (physical activity) and the visual analogue scale (VAS) for fatigue and comfort. A 10-meter walk test will be evaluated on duration.

Expected findings: In a first phase the novel device will probably reduce walking and cognitive performance, whereas fine-tuning the mechatronics (after several retests) should improve walking and cognitive performance during walking.