Quantitative Assessment of Upper Limb Motor Function in Ethiopian Acquired Brain Injured Patients Using a Low-Cost Wearable Sensor

Abstract

Acquired brain injuries place a significant burden on sub-Saharan African rehabilitation clinicians and health care facilities. While wearable sensors have the potential to alleviate these issues, many are beyond the financial capabilities of the majority of African persons and clinics. To bridge this gap, we have developed a low-cost wrist-worn sensor (the outREACH sensor) capable of accurately measuring upper limb movement kinematics. In this study we evaluated the extent to which the outREACH sensor is sensitive to the hand performing the task (unimpaired, impaired) and level of impairment (mild, moderate) in 14 Ethiopian persons with acquired brain injury (mean age = 51.6 ± 12.2 years, 1 female, 13 male). Participants performed an object manipulation task with both the impaired and the unimpaired limb, and reaching performance was measured using standard kinematic measures (i.e., movement time, spectral arc length, peak velocity, peak acceleration, mean velocity, mean acceleration). Overall, movements were smoother and faster when performed by the patient's unimpaired limb. In contrast, maximum velocity did not differ between the two limbs. Moreover, the outREACH sensor was sensitive to differences in performance-based upper limb impairment. Fugl-Meyer assessment for upper extremity scores were significantly correlated with movement time, spectral arc length, and peak velocity. Upper limb movement kinematics can be accurately measured using the outREACH sensor. The outREACH sensor can be a valuable addition to standardized clinical measures that provides rehabilitation clinicians with information regarding initial upper limb impairment level and changes in function across the rehabilitation lifespan.

Accuracy and Validity of a Single Inertial Measurement Unit-Based System to Determine Upper Limb Kinematics for Medically Underserved Populations

“…Aligning with previous studies ( Hughes et al, 2019a ; Hughes et al, 2019b ), we have shown promising validity for movement kinematics detected using single IMU-based systems. Although increasing the number of IMUs would allow for the calculation of kinematics across multiple joints, it would also increase the cost of the system as well as its usability as a decentralized rehabilitation tool.…”

“…Another enabling technology are inertial measurement units (IMUs) that exhibit great potential as a low-cost, portable means to evaluate and monitor patient progress during decentralized rehabilitation protocols ( Parrington et al, 2021 ). IMUs have been shown to accurately measure motor function and provide information regarding the different motor components that contribute to task performance, (e.g., movement accuracy, efficiency, precision, smoothness) ( Hughes et al, 2019a ; Schwarz et al, 2019 ), with kinematic variables obtained by IMU-based system correlating with standard clinical assessments ( Hughes et al, 2019b ; Oubre et al, 2020 ; Chen et al, 2021 ). For example, Hughes et al (2019a) , Hughes et al (2019b) developed a low-cost IMU-based wearable sensor specifically designed for medically underserved populations.…”

“…IMUs have been shown to accurately measure motor function and provide information regarding the different motor components that contribute to task performance, (e.g., movement accuracy, efficiency, precision, smoothness) ( Hughes et al, 2019a ; Schwarz et al, 2019 ), with kinematic variables obtained by IMU-based system correlating with standard clinical assessments ( Hughes et al, 2019b ; Oubre et al, 2020 ; Chen et al, 2021 ). For example, Hughes et al (2019a) , Hughes et al (2019b) developed a low-cost IMU-based wearable sensor specifically designed for medically underserved populations. The validity of the sensor was recently compared to a gold standard optoelectronic motion capture system ( Hughes et al, 2019a ), with results indicating strong positive correlations and agreement with the reference system across three tasks used to measure post-stroke arm function and impairment.…”

“…For example, Hughes et al (2019a) , Hughes et al (2019b) developed a low-cost IMU-based wearable sensor specifically designed for medically underserved populations. The validity of the sensor was recently compared to a gold standard optoelectronic motion capture system ( Hughes et al, 2019a ), with results indicating strong positive correlations and agreement with the reference system across three tasks used to measure post-stroke arm function and impairment. The sensitivity of the sensor was then tested in Ethiopian acquired brain injured patients ( Hughes et al, 2019b ), with results demonstrating that the sensor is capable of deriving movement kinematics (e.g., movement time, movement smoothness, and peak velocity) that can discriminate between arm impairment levels, as measured by the Fugl-Meyer Upper Extremity Motor Assessment.…”

Kinematic Evaluation via Inertial Measurement Unit Associated with Upper Extremity Motor Function in Subacute Stroke: A Cross-Sectional Study

“…Such technology is capable of providing detailed information regarding upper extremity function evaluation and delivering personalized interventions. According to the previous literature, kinematic assessment is usually performed using arm-supported robots or optical-camera systems, based on fixed laboratory environments or expensive equipment that leads to several disadvantages [11][12][13]. From the technical perspective, robotic instruments are unable to capture the entire spectrum of UE motor impairment due to their mechanical structure [14].…”