Real-Time Estimation of Temporal Gait Parameters in Lower Limb Amputees using Inertial Sensors

Number of individuals undergoing lower limb amputation around the world is
increasing every year due to vascular diseases or complications associated with
conditions such as diabetes and trauma. Limb loss has a profound impact on
individual’s physical, mental and vocational abilities, resulting in the degradation of
amputees’ quality of life (QOL). Following an amputation, prescription of prosthetic
devices serves as an important step in improving the amputees’ QOL.
Restoring functional attributes of human gait is one of the key objectives of
lower limb rehabilitation. A number of studies have been carried out to evaluate the
use of wearable sensors, especially the Inertial Measurement Unit (IMU), placed at
different body locations to identify gait events/phases. However, a survey of the
literature indicated a lack of research in development of a real-time gait event/phase
detection for lower limb amputees using a single IMU attached to the shank or the
prosthetic pylon.
This research presents the development and evaluation of a low-cost
portable gait monitoring system which detects the temporal gait events, namely
initial contact (IC), foot-flat start (FFS), heel-off (HO) and toe-off TO in real-time
while performing level ground and ramp activities. Foot-switches (FSW) placed
underneath the foot were used as a reference system. Evaluation of the time
difference recorded between the IMU and the FSW confirmed good accuracy and
precision of the proposed system. Overall results showed 100% detection of IC, FFS
and TO and 98.3% detection of HO in both groups (control and amputee) across all
the activities. Finally, to demonstrate its practicality, the proposed system was used
to evaluate and analyse the gait asymmetry for overground and treadmill walking.
Detecting the temporal gait events/phases provide useful information about
clinical parameters such as stance time, swing time, gait cycle duration and gait
asymmetry. The proposed system could be used as a monitoring tool to assess the
progress through rehabilitation, or in the development of control systems for lower
limb amputees and patients with abnormal and pathological gait.