Smart Eyeglasses: A Valid and Reliable Device to Assess Spatiotemporal Parameters during Gait

Abstract

The study aims to determine the validity and reproducibility of step duration and step length parameters measured during walking in healthy participants using an accelerometer embedded in smart eyeglasses. Twenty young volunteers participated in two identical sessions comprising a 30 s gait assessment performed at three different treadmill speeds under two conditions (i.e., with and without a cervical collar). Spatiotemporal parameters (i.e., step duration and step length normalized by the lower limb length) were obtained with both the accelerometer embedded in smart eyeglasses and an optoelectronic system. The relative intra- and inter-session reliability of step duration and step length computed from the vertical acceleration data were excellent for all experimental conditions. An excellent absolute reliability was observed for the eyeglasses for all conditions and concurrent validity between systems was observed. An accelerometer incorporated in smart eyeglasses is accurate to measure step duration and step length during gait.

Keywords: accelerometer; reliability; reproducibility; spatiotemporal parameters; validity; wearable sensor.

Figure 1

Participant walking on the treadmill with the equipment set up (A) and 3D schematic representation of the gait analysis laboratory (B).

Figure 2

Position of the retroreflective marker on the right arm of the glasses and axes of the IMU and retroreflective marker.

Figure 3

Acceleration signals from the glasses and optoelectronic system during gait cycle in 0.90 m/s speed without a cervical collar for one participant (red and blue colors indicate the right and the left lower limb, respectively).

Figure 4

Pearson’s correlation of the step duration measured with the optoelectronic system and the glasses during the 30 s of gait at 0.90 m/s without a cervical collar for both test sessions.

Figure 5

Pearson’s correlation of the step length normalized by the lower limb length measured with the optoelectronic system and the glasses during 30 s of gait at 0.90 m/s without a cervical collar for both test sessions.

Figure 6

Bland-Altman plots of the step duration recorded without a cervical collar during the moderate speed condition (i.e., 0.90 m/s) for both testing sessions showing the differences between the glasses and OptiTrack against the mean of the two systems. The solid horizontal line represents the estimated bias, and the dashed lines represent the 95% limits of agreement.