Test-Retest Reliability and Minimal Detectable Changes for Wearable Sensor-Derived Gait Stability, Symmetry, and...

Area of Science:

• Biomedical Engineering
• Rehabilitation Science
• Neurology

Background:

• Severe traumatic brain injury (sTBI) frequently causes gait impairments.
• Inertial measurement units (IMUs) offer objective gait analysis, but their use in sTBI populations requires validation.
• Clinometric properties of IMU-derived gait indices in sTBI survivors are not well-established.

Purpose of the Study:

• To evaluate the test-retest reliability and minimal detectable change (MDC) of three IMU-derived gait indices.
• To assess normalized Root Mean Square (nRMS), improved Harmonic Ratio (iHR), and Log Dimensionless Jerk (LDLJ) in sTBI survivors.
• To determine the clinical applicability of these indices for gait assessment in sTBI.

Main Methods:

• Forty-nine sTBI survivors performed a 10 m walking test with IMUs on key body segments.
• Test-retest reliability was assessed using intraclass correlation coefficients (ICCs).
• Minimal detectable change (MDC) was calculated to determine the smallest detectable difference.

Main Results:

• nRMS and iHR demonstrated moderate to excellent reliability in anteroposterior and craniocaudal directions (ICC: 0.78-0.95).
• Small MDC values (0.04-0.3) for nRMS and iHR suggest clinical utility.
• LDLJ showed moderate reliability (ICC: 0.57-0.77) with higher MDC values, indicating a need for further validation.

Conclusions:

• Specific IMU-derived indices (nRMS, iHR) are reliable and sensitive for quantifying gait changes in sTBI survivors.
• These findings support the use of IMUs for refined gait assessments and monitoring rehabilitation in sTBI.
• Further research is needed to explore the responsiveness of these indices to interventions and their correlation with functional outcomes.