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Repeatability of a new anatomically based protocol for gait analysis in adult subjects
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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
S15
tion [1]. The present study demonstrates that a good level of inter observer reliability was achieved, and also that the gait analysis results are not affected much by the possible little experience of the examiner. References [1] Leardini, et al. Gait Posture 2007;26:560–71. [2] Schwartz, et al. Gait Posture 2004;20:196–203.
doi:10.1016/j.gaitpost.2009.08.024 Day 2 – 18 September 2009, Session 4: Muscle and Electromyography, 08:30–10:30, Lecture Theatre O21 The accuracy of surface electromyography electrode placement over rectus femoris muscle Seif Sawalha ∗ , Gill Holmes, Danieli Trinca, Shreyash Gajjar, Alfie Bass Alder Hey Children’s Hospital, Liverpool, United Kingdom
Fig. 1. Sources of variation in gait kinematics.
Two healthy adults underwent 12 gait analysis sessions each (5 trials per session, 1 session a week for 3 times, each one conducted by two physiotherapists and two physicians as the ‘observer’). All the repetitions were randomized to minimize the risk of reminding by the observer. Observer A had a long experience in marker mounting, observer B had a good practice in gait analysis but less in the protocol under assessment, observers C and D had high clinical experience but no practice on patient preparation in gait analysis. The three observers with lower experience were trained for 2 h in marker positioning according to recommendation implied in the protocol. The mean and standard deviation (S.D.) were calculated on each sample of the joint rotations on the 5 trials for each subject (intra-subject variability). The SD of the joint rotations obtained on the three sessions by each evaluator was used to calculate the inter-session variability (or intra-observer); the interobserver error was measured on the two subjects by the mean of evaluator’s S.D.; to estimate experimental errors we have used the ratio r = Inter-observer/ Inter-trial. Fig. 1 reports S.D. under the three sources of variability in each anatomical plane. The inter-trials variability appears the smallest among the three and ranged from Avg S.D. 0.86◦ for pelvic tilt to Avg S.D. 4.25◦ for knee rotation. The inter-observer variability was the largest among the three errors and it ranged from Avg S.D. 1.57◦ for pelvic obliquity to 6.25◦ for knee rotation; in general we can see that transversal plane joint angles Avg S.D. are the most variable except for the pelvic one, but the extrinsic error (r = Inter-observer/ Inter-trial) appears generally very low with a range from r = 2.21◦ for pelvic tilt to r = 1.04◦ for pelvic rotation. The main aim of Total3DGait protocol, based explicitly on anatomical references and international recommendations for human movement analysis, was to minimize the effects of the experimental errors associated to anatomical landmarks identifica-
Summary The Surface Electromyography for the Non-Invasive Assessment of Muscles (SENIAM) guidelines for surface electromyography (SEMG) electrode location over rectus femoris (RF) muscle were validated in 10 healthy adults and 10 children with cerebral palsy (CP) using ultrasonography. While there was no significant difference in electrode location between SENIAM and ultrasonography in healthy adults, the difference in children with CP was significant. Conclusions Ultrasonography is a simple and useful method for determining SEMG electrode location over RF in children with CP. Introduction Distal RF transfer to Sartorius is one of the treatment options for children with CP who exhibit stiff-knee gait and, therefore, assessment of RF activation patterns is important in selecting patients for this procedure [1]. The assessment of RF depends on the signal recorded from SEMG electrodes. In the transverse plane, the electrode should be placed away from the edges with other adjacent muscles to reduce crosstalk [2]. The SENIAM recommendations for electrode placement are widely accepted but have not been validated. The aim of this study is to validate the SENIAM recommendations for RF electrode location in healthy adults and in children with CP using ultrasonography. Patients and methods The study included 10 healthy adult (mean age 30 years) and 10 children with CP (mean age 10 years). The RF electrode location was marked on the thigh halfway between the anterior superior iliac spine and the superior surface of the patella according to SENIAM guidelines [2]. An ultrasound scanner was used to identify the medial and lateral edges of RF and their positions were marked on the skin in the same horizontal line as the RF electrode location. The electrode location was expressed by the ratio: (distance between electrode location and lateral edge of RF/width of RF)%. The ideal electrode location was considered 50%, i.e. halfway between the medial and lateral edges of RF. Results In the healthy adults, the mean electrode location was 47% (range 33–60%). This was not significantly different from the ideal
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
S15
tion [1]. The present study demonstrates that a good level of inter observer reliability was achieved, and also that the gait analysis results are not affected much by the possible little experience of the examiner. References [1] Leardini, et al. Gait Posture 2007;26:560–71. [2] Schwartz, et al. Gait Posture 2004;20:196–203.
doi:10.1016/j.gaitpost.2009.08.024 Day 2 – 18 September 2009, Session 4: Muscle and Electromyography, 08:30–10:30, Lecture Theatre O21 The accuracy of surface electromyography electrode placement over rectus femoris muscle Seif Sawalha ∗ , Gill Holmes, Danieli Trinca, Shreyash Gajjar, Alfie Bass Alder Hey Children’s Hospital, Liverpool, United Kingdom
Fig. 1. Sources of variation in gait kinematics.
Two healthy adults underwent 12 gait analysis sessions each (5 trials per session, 1 session a week for 3 times, each one conducted by two physiotherapists and two physicians as the ‘observer’). All the repetitions were randomized to minimize the risk of reminding by the observer. Observer A had a long experience in marker mounting, observer B had a good practice in gait analysis but less in the protocol under assessment, observers C and D had high clinical experience but no practice on patient preparation in gait analysis. The three observers with lower experience were trained for 2 h in marker positioning according to recommendation implied in the protocol. The mean and standard deviation (S.D.) were calculated on each sample of the joint rotations on the 5 trials for each subject (intra-subject variability). The SD of the joint rotations obtained on the three sessions by each evaluator was used to calculate the inter-session variability (or intra-observer); the interobserver error was measured on the two subjects by the mean of evaluator’s S.D.; to estimate experimental errors we have used the ratio r = Inter-observer/ Inter-trial. Fig. 1 reports S.D. under the three sources of variability in each anatomical plane. The inter-trials variability appears the smallest among the three and ranged from Avg S.D. 0.86◦ for pelvic tilt to Avg S.D. 4.25◦ for knee rotation. The inter-observer variability was the largest among the three errors and it ranged from Avg S.D. 1.57◦ for pelvic obliquity to 6.25◦ for knee rotation; in general we can see that transversal plane joint angles Avg S.D. are the most variable except for the pelvic one, but the extrinsic error (r = Inter-observer/ Inter-trial) appears generally very low with a range from r = 2.21◦ for pelvic tilt to r = 1.04◦ for pelvic rotation. The main aim of Total3DGait protocol, based explicitly on anatomical references and international recommendations for human movement analysis, was to minimize the effects of the experimental errors associated to anatomical landmarks identifica-
Summary The Surface Electromyography for the Non-Invasive Assessment of Muscles (SENIAM) guidelines for surface electromyography (SEMG) electrode location over rectus femoris (RF) muscle were validated in 10 healthy adults and 10 children with cerebral palsy (CP) using ultrasonography. While there was no significant difference in electrode location between SENIAM and ultrasonography in healthy adults, the difference in children with CP was significant. Conclusions Ultrasonography is a simple and useful method for determining SEMG electrode location over RF in children with CP. Introduction Distal RF transfer to Sartorius is one of the treatment options for children with CP who exhibit stiff-knee gait and, therefore, assessment of RF activation patterns is important in selecting patients for this procedure [1]. The assessment of RF depends on the signal recorded from SEMG electrodes. In the transverse plane, the electrode should be placed away from the edges with other adjacent muscles to reduce crosstalk [2]. The SENIAM recommendations for electrode placement are widely accepted but have not been validated. The aim of this study is to validate the SENIAM recommendations for RF electrode location in healthy adults and in children with CP using ultrasonography. Patients and methods The study included 10 healthy adult (mean age 30 years) and 10 children with CP (mean age 10 years). The RF electrode location was marked on the thigh halfway between the anterior superior iliac spine and the superior surface of the patella according to SENIAM guidelines [2]. An ultrasound scanner was used to identify the medial and lateral edges of RF and their positions were marked on the skin in the same horizontal line as the RF electrode location. The electrode location was expressed by the ratio: (distance between electrode location and lateral edge of RF/width of RF)%. The ideal electrode location was considered 50%, i.e. halfway between the medial and lateral edges of RF. Results In the healthy adults, the mean electrode location was 47% (range 33–60%). This was not significantly different from the ideal