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Intra- and inter-laboratory repeatability of gait analysis data in normal adults
S14
Abstracts / Gait & Posture 30S (2009) S1–S153
Fig. 1. Yearly average kinematic curves for Workstation® system (dashed) and the Nexus® system (solid, ±1 S.D.).
References [1] Bucknall V, et al. Gait Posture 2008;28(2):S33–4. [2] Pratt E, et al.; in process.
doi:10.1016/j.gaitpost.2009.08.022 O19 Intra- and inter-laboratory repeatability of gait analysis data in normal adults Joseph Bevins 1 , Sarah Churchill 1 , Mark Corbett 1,∗ , Ralph Palmer 2 , David Pratt 2 , Anne Uutela 2 1 2
University of Worcester, Worcester, United Kingdom South Birmingham Primary Care Trust, Birmingham, United Kingdom
Summary Gait analysis data has been compared from two independent laboratories with similar measurement protocols (Vicon Plugin Gait) but significant differences in hardware and software. A hierarchical approach has been used to determine inter-trial, intersession and ultimately inter-laboratory repeatability. Conclusions Inter-trial and inter-session repeatability were both good and compare well to published data. Inter-laboratory repeatability varied from fair to poor and was characterised by fixed angular offsets, indicative of systematic differences in marker application. Introduction Reproducibility and error control are critical to delivering quality clinical gait analysis. Several studies have reported intrarepeatability (within) and inter-repeatability (between) across trials, sessions and observers under various conditions. However, data is scarce when comparing repeatability across different laboratories, where additional compounding factors are present. Patients/materials and methods Ten healthy adults were measured at both laboratories over 10 trials walking at their natural speed. 3D movement analysis (Vicon) and force vector (Kistler/AMTI) data were collected. Markering, data capture and processing were all conducted according to the respective laboratory standard protocols. Five measurements were also repeated on selected subjects at each laboratory over several weeks to establish inter-session repeatability. Absolute values and standard coefficients of variation of thirteen temporo-spatial parameters (e.g. cadence, walking speed) were compared directly. Lower body kinematic waveforms were compared using coefficients of multiple correlation (CMCs) [1]. Results All parameters and measures of repeatability were bilaterally symmetric and similar across subjects. Repeatability between the
laboratories in temporo-spatial parameters was extremely good with an overall difference of less than 0.5%. Inter-trial repeatability (intra-session, subject and laboratory) of kinematics was high (CMC > 0.9) at both laboratories across all sagittal and frontal plane parameters except for pelvic tilt (CMC ∼ 0.5). Intra-trial repeatability in the transverse plane was good (>0.8). Inter-session repeatability was again high (>0.9) in the sagittal and frontal planes, except for pelvic tilt which was poor. Transverse plane repeatability was fair (>0.7). Subtraction of means improved repeatability to high (>0.9) for all segments indicating the presence of fixed angular offsets. Inter-laboratory repeatability was good (>0.8) in the sagittal plane apart from pelvic tilt. Frontal plane was fair (>0.7) apart from knee ab/adduction (∼0.5). The transverse plane was fair for pelvic and foot rotation but poor (∼0.2) for hip and knee rotation. Subtraction of means again improved repeatability significantly to good (>0.8) for most segments though knee ab/adduction, hip rotation and knee rotation showed less improvement. Discussion Very good agreement in spatio-temporal parameters demonstrates consistency in the underlying measurement protocols at the laboratories. Kinematic repeatability follows a predictable trend down through the trial-session-laboratory hierarchy. Reduced repeatability in frontal and transverse plane knee and hip kinematics may be related to use of a knee alignment device (KAD) at only one of the laboratories.
Reference [1] Growney E, et al. Repeated measures of adult normal walking using a video tracking system. Gait and Posture 1997;6:147–62.
doi:10.1016/j.gaitpost.2009.08.023 O20 Repeatability of a new anatomically based protocol for gait analysis in adult subjects Maria Grazia Benedetti 1,∗ , Stefano Cavazza 2 , Giovanni Ferraresi 2 , Mario Manca 2 , Pia Marchi 2 , Emanuele Zanaga 2 , Alberto Leardini 1 1
Movement Analysis Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy 2 Dipartimento della Riabilitazione San Giorgio, Ferrara, Italy Variability in gait analysis patterns of motion can be introduced by the examiner during marker positioning. The purpose of the present study was to estimate the inter-trial variation along with intra-observer and inter-observer errors for the recently proposed Total3DGait [1] gait analysis protocol, by using a standard method [2].
Abstracts / Gait & Posture 30S (2009) S1–S153
Fig. 1. Yearly average kinematic curves for Workstation® system (dashed) and the Nexus® system (solid, ±1 S.D.).
References [1] Bucknall V, et al. Gait Posture 2008;28(2):S33–4. [2] Pratt E, et al.; in process.
doi:10.1016/j.gaitpost.2009.08.022 O19 Intra- and inter-laboratory repeatability of gait analysis data in normal adults Joseph Bevins 1 , Sarah Churchill 1 , Mark Corbett 1,∗ , Ralph Palmer 2 , David Pratt 2 , Anne Uutela 2 1 2
University of Worcester, Worcester, United Kingdom South Birmingham Primary Care Trust, Birmingham, United Kingdom
Summary Gait analysis data has been compared from two independent laboratories with similar measurement protocols (Vicon Plugin Gait) but significant differences in hardware and software. A hierarchical approach has been used to determine inter-trial, intersession and ultimately inter-laboratory repeatability. Conclusions Inter-trial and inter-session repeatability were both good and compare well to published data. Inter-laboratory repeatability varied from fair to poor and was characterised by fixed angular offsets, indicative of systematic differences in marker application. Introduction Reproducibility and error control are critical to delivering quality clinical gait analysis. Several studies have reported intrarepeatability (within) and inter-repeatability (between) across trials, sessions and observers under various conditions. However, data is scarce when comparing repeatability across different laboratories, where additional compounding factors are present. Patients/materials and methods Ten healthy adults were measured at both laboratories over 10 trials walking at their natural speed. 3D movement analysis (Vicon) and force vector (Kistler/AMTI) data were collected. Markering, data capture and processing were all conducted according to the respective laboratory standard protocols. Five measurements were also repeated on selected subjects at each laboratory over several weeks to establish inter-session repeatability. Absolute values and standard coefficients of variation of thirteen temporo-spatial parameters (e.g. cadence, walking speed) were compared directly. Lower body kinematic waveforms were compared using coefficients of multiple correlation (CMCs) [1]. Results All parameters and measures of repeatability were bilaterally symmetric and similar across subjects. Repeatability between the
laboratories in temporo-spatial parameters was extremely good with an overall difference of less than 0.5%. Inter-trial repeatability (intra-session, subject and laboratory) of kinematics was high (CMC > 0.9) at both laboratories across all sagittal and frontal plane parameters except for pelvic tilt (CMC ∼ 0.5). Intra-trial repeatability in the transverse plane was good (>0.8). Inter-session repeatability was again high (>0.9) in the sagittal and frontal planes, except for pelvic tilt which was poor. Transverse plane repeatability was fair (>0.7). Subtraction of means improved repeatability to high (>0.9) for all segments indicating the presence of fixed angular offsets. Inter-laboratory repeatability was good (>0.8) in the sagittal plane apart from pelvic tilt. Frontal plane was fair (>0.7) apart from knee ab/adduction (∼0.5). The transverse plane was fair for pelvic and foot rotation but poor (∼0.2) for hip and knee rotation. Subtraction of means again improved repeatability significantly to good (>0.8) for most segments though knee ab/adduction, hip rotation and knee rotation showed less improvement. Discussion Very good agreement in spatio-temporal parameters demonstrates consistency in the underlying measurement protocols at the laboratories. Kinematic repeatability follows a predictable trend down through the trial-session-laboratory hierarchy. Reduced repeatability in frontal and transverse plane knee and hip kinematics may be related to use of a knee alignment device (KAD) at only one of the laboratories.
Reference [1] Growney E, et al. Repeated measures of adult normal walking using a video tracking system. Gait and Posture 1997;6:147–62.
doi:10.1016/j.gaitpost.2009.08.023 O20 Repeatability of a new anatomically based protocol for gait analysis in adult subjects Maria Grazia Benedetti 1,∗ , Stefano Cavazza 2 , Giovanni Ferraresi 2 , Mario Manca 2 , Pia Marchi 2 , Emanuele Zanaga 2 , Alberto Leardini 1 1
Movement Analysis Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy 2 Dipartimento della Riabilitazione San Giorgio, Ferrara, Italy Variability in gait analysis patterns of motion can be introduced by the examiner during marker positioning. The purpose of the present study was to estimate the inter-trial variation along with intra-observer and inter-observer errors for the recently proposed Total3DGait [1] gait analysis protocol, by using a standard method [2].