  Elderly gait is a source of rich information about their physical and mental
health condition. As an alternative to the multiple sensors on the lower body
parts, a single sensor on the pelvis has a positional advantage and an
abundance of information acquirable. This study aimed to explore a way of
improving the accuracy of gait event detection in the elderly using a single
sensor on the waist and deep learning models. Data was gathered from elderly
subjects equipped with three IMU sensors while they walked. The input was taken
only from the waist sensor was used to train 16 deep-learning models including
CNN, RNN, and CNN-RNN hybrid with or without the Bidirectional and Attention
mechanism. The groundtruth was extracted from foot IMU sensors. Fairly high
accuracy of 99.73% and 93.89% was achieved by the CNN-BiGRU-Att model at the
tolerance window of $\pm$6TS ($\pm$6ms) and $\pm$1TS ($\pm$1ms) respectively.
Advancing from the previous studies exploring gait event detection, the model
showed a great improvement in terms of its prediction error having an MAE of
6.239ms and 5.24ms for HS and TO events respectively at the tolerance window of
$\pm$1TS. The results showed that the use of CNN-RNN hybrid models with
Attention and Bidirectional mechanisms is promising for accurate gait event
detection using a single waist sensor. The study can contribute to reducing the
burden of gait detection and increase its applicability in future wearable
devices that can be used for remote health monitoring (RHM) or diagnosis based
thereon.
