Quantitative Assessment of the Motion of the Lumbar Spine and Pelvis with Wearable Inertial Sensors

Abstract

Chronic Low Back Pain (CLBP) is a leading cause of disability with significant economic costs and severe psychological and social consequences. LBP patients also have the tendency to change the movement of the back and hold the pelvis rigid. Currently, the clinical assessment of a LBP patient is undertaken at a single point in time during clinic visits rather than through continuous monitoring. To monitor motion of the lumbar spine and pelvis, we have developed a wearable prototype sensor based on inertial sensor technology combined with the Body Sensor Network (BSN) platform. The device enables quantitative assessment of motion, especially the proportion of pelvic to lumbar movement. The developed device has been tested in a pilot study with healthy volunteers for a range of movements and results validated by optical tracking. This paper presents our approach and exemplifies the quantitative assessment of the lateral flexion movement. The next stage of the project will involve testing with patients.

Validity and Reliability of a New Inertial Device for Monitoring Range of Motion at the Pelvis during Sexual Intercourse

“…Other studies that have validated inertial sensors by comparing them with optical systems for capturing the range of motion in the same axis of movement (flexion-extension) found the following systematic differences in evaluations of the hip movement: 1.55° (during a hip flexion test) [30] [32]; in evaluations of the range of motion of the trunk during a sit-to-walk test: 0.45° [30]; in the range of motion of the lumbar spine during a standing forward flexion test: 1.82° [33], in the range of lumbar-pelvic movement during a standing forward flexion test: 3.06° [21]. The following additional statistics were reported: R 2 = 0.78 [21] and R 2 = 0.82 [34]; SEM = 2.47° [32] and SEM = 3° [31,33], and an ICC of 0.99 [35].…”

Body Sensor Networks: A Holistic Approach From Silicon to Users

“…The form factor of COTS based platforms can be small (volume <1 cm 3 , weight <100 g [11]) and wearable, using either skin mountable [12] or Velcro chest strap designs [13], although many COTS nodes remain several cm's on a side. Their energy inefficiencies may ultimately limit the full deployment of COTS designs in a wide range of emerging healthcare applications, as it is difficult to prolong the battery lifetime of a COTS platform to much more than 1 day [14] [15].…”

“…A survey across different platforms shows that the 868 MHz unregulated band [14][16] and the 2.4 GHz band [15] are popular for COTS platforms, since they provide easy integration with the larger system. The power consumption of these radios makes the COTS node power alarmingly high, often reaching the several 100 mW range [11][17] [16] (500 mW for [17]).…”

Human Back Movement Analysis Using BSN

“…King et al [11] presented a system for monitoring the rotation of the lower back (sacrum and thoraco-lumbar junction) and femur in the sagittal plane using inertial sensors integrated with Body Sensor Network (BSN) nodes. Chhikara et al [12] also developed a wearable prototype based on BSN nodes to quantify pelvic to lumbar movement of the spine. Both methods are limited to rotational movement in the sagittal plane, which in effect represents only one dimensional back movement estimation.…”