IMU-based kinematic measures effectively capture reduced daily upper limb use in persons with stroke and demonstrate associations with clinical impairment, supporting the potential of wearable sensors to quantify daily arm use as an ecologically valid indicator of activity performance and recovery.
Key Findings
Results
All three IMU-derived kinematic measures were significantly reduced in the paretic arm compared with the non-paretic arm in persons with stroke.
The three measures assessed were wrist path length, cumulative elbow angular displacement, and movement space volume.
Statistical significance was p < 0.001 for all measures.
Nineteen individuals in the subacute stage after stroke participated in the study.
Participants wore five IMU sensors during routine daytime activities in a rehabilitation hospital.
Results
Cumulative elbow angular displacement demonstrated the strongest association with clinical impairment measures, particularly with ARAT scores.
Asymmetry indices derived from each kinematic measure were correlated with clinical assessments.
Clinical assessments included the Fugl-Meyer Assessment for the upper extremity (FMA-UE), Action Research Arm Test (ARAT), and grip strength.
Cumulative elbow angular displacement showed the strongest association specifically with ARAT scores compared to the other two kinematic measures.
All asymmetry indices showed significant correlations with clinical impairment measures.
Results
Asymmetry indices derived from IMU kinematic measures showed significant correlations with clinical assessments of motor impairment in stroke survivors.
Three asymmetry indices were constructed by combining paretic and non-paretic arm measures for each kinematic variable.
Clinical measures used for correlation included FMA-UE, ARAT, and grip strength.
The study sample consisted of 19 individuals in the subacute stage after stroke.
Correlations were analyzed between all three asymmetry indices and the clinical measures.
Methods
Five IMU sensors worn during routine daytime activities in a rehabilitation hospital provided a feasible method for capturing real-world upper limb use in the subacute post-stroke period.
The study enrolled 19 individuals in the subacute stage after stroke.
Sensors were worn during routine daytime activities within a rehabilitation hospital setting.
Three kinematic measures were extracted: wrist path length, cumulative elbow angular displacement, and movement space volume.
The approach was designed to address the discrepancy between motor capacity observed in clinical settings and actual performance of daily activities.
Background
Clinical motor assessments often fail to capture spontaneous upper limb use, motivating the need for objective, ecologically valid monitoring tools such as wearable IMUs.
Upper limb impairment is described as one of the most common and disabling consequences of stroke.
The discrepancy between motor capacity observed in clinical settings and actual daily performance is highlighted as a key gap.
Wearable IMUs are identified as having emerged as a feasible methodology for quantifying real-world upper limb use.
The clinical interpretability and validity of IMU-derived kinematic metrics in persons with stroke were noted as insufficiently established prior to this study.
What This Means
This research suggests that small wearable motion sensors (called inertial measurement units, or IMUs) can objectively measure how much stroke survivors actually use their affected arm during everyday activities. In this study, 19 people recovering from stroke wore five sensors on their arms and trunk while going about their normal daily routines in a rehabilitation hospital. The sensors tracked three different aspects of arm movement: how far the wrist traveled, how much the elbow bent and straightened, and how large a space the arm moved through. All three measures consistently showed that the stroke-affected arm was used significantly less than the unaffected arm.
Importantly, these sensor-based measurements were also meaningfully linked to standard clinical tests that therapists and doctors use to assess arm function after stroke, such as the Fugl-Meyer Assessment and the Action Research Arm Test. The measure of elbow bending and straightening (cumulative elbow angular displacement) had the strongest connection to clinical test scores. This suggests that the sensor measurements are not just capturing raw movement but are reflecting genuine differences in arm function.
This research matters because standard clinical assessments measure what a patient can do in a controlled setting, which may not reflect how much they actually use their arm at home or during everyday life. Wearable sensors could fill this gap by providing a more realistic picture of recovery and daily arm use, potentially helping clinicians better track progress and tailor rehabilitation programs to real-world needs.
Goldhamer N, Koren Y, Mizrahi T, Lorber-Haddad A, Binyamin-Netser R, Shmuelof L. (2026). Quantification of daily upper arm use after stroke using an IMU-based kinematic model.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1860647