Portable Sensors Add Reliable Kinematic Measures to the Assessment of Upper Extremity Function

Abstract

Ordinal scales with low resolution are used to assess arm function in clinic. These scales may be improved by adding objective kinematic measures. The aim was to analyze within-subject, inter-rater and overall reliability (i.e., including within-subject and inter-rater reliability) and check the system’s validity of kinematic measures from inertial sensors for two such protocols on one person. Twenty healthy volunteers repeatedly performed two tasks, finger-to-nose and drinking, during two test sessions with two different raters. Five inertial sensors, on the forearms, upper arms and xiphoid process were used. Comparisons against an optical camera system evaluated the measurement validity. Cycle time, range of motion (ROM) in shoulder and elbow were calculated. Bland–Altman plots and linear mixed models including the generalizability (G) coefficient evaluated the reliability of the measures. Within-subject reliability was good to excellent in both tests (G = 0.80–0.97) and may serve as a baseline when assessing upper extremities in future patient groups. Overall reliability was acceptable to excellent (G = 0.77–0.94) for all parameters except elbow axial rotation in finger-to-nose task and both elbow axial rotation and flexion/extension in drinking task, mainly due to poor inter-rater reliability in these parameters. The low to good reliability for elbow ROM probably relates to high within-subject variability. The sensors provided good to excellent measures of cycle time and shoulder ROM in non-disabled individuals and thus have the potential to improve today’s assessment of arm function.

Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking? A Clinical Pilot Study Based on Wearable Motion Sensors

“…A problem with this method is that it is only available to specialized centers due to high costs and requirements of expert operation. Alternatively, portable systems based on inertial measurement units (IMUs) show promising results for different clinical applications assessing gait and lower limb joint angles [25,26,27,28,29,30,31]. A recent review compared IMU systems to standard systems used in gait analysis [31] and concluded that portable IMU systems can be used for this purpose in clinical settings with good reliability.…”

Human-In-The-Loop Assessment of an Ultralight, Low-Cost Body Posture Tracking Device

“…We here assess the device through an experiment involving 10 users in an online trajectory-tracking task in VR, showing that it affords an average precision of 0.66 cm during a precision task and 6.33 cm while tracking a target moving along a prerecorded trajectory, when tested in the full peri-personal space of a user. These values are much larger than the absolute precision of the VR system employed in the experiment, which appears reasonable, given the pointing precision attainable by a human being [14].Potential applications of this device, not limited to rehabilitation robotics [15] and discussed in detail at the end of this paper, are endless.…”

“…Potential applications of this device, not limited to rehabilitation robotics [15] and discussed in detail at the end of this paper, are endless.…”

How Many Trials Are Needed in Kinematic Analysis of a Reach-to-Grasp Task? - a Study in Persons With Stroke and Non-Disabled Controls

“…The results of the current study are only applicable for the kinematic motion capture systems using multiple optoelectronic cameras. The results seem, however, to be similar even when the kinematics are collected by other systems, such as Kinect camera or inertial sensors (32,33). This is promising, taking the constant push from users (clinicians, researchers and patients) to make movement analysis more readily available with systems that can operate outside the lab.…”

“…A study using a virtual reality gaming Kinect system showed that 2 to 5 trials during reaching were needed to achieve performance stability in movement time and elbow and shoulder range of motion (32). Additionally, when using an inertial sensor system, comparable results of 3 trials was considered enough to reach acceptable levels of reliability for movement time and shoulder and elbow range of motion during a drinking task in non-disabled participants (33). These results con rm that for most of the kinematic variables a set of 3 trials would be su cient.…”