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Can stability in hemiplegic and asymmetric diplegic gait be determined by simple RPA calculation?
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Abstracts / Gait & Posture 30S (2009) S1–S153
relatively small talus and calcaneus makes the bones difficult to measure compared to the tibia. Whether the reason to discrepancy is caused by relative disuse, less muscle activity and loading on the hemiplegic side or is directly related to the brain injury is not clear. This limited study suggests a relation between degree of involvement in hemiplegic CP and location of leg length discrepancy. References [1] Palisano R. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol 1997;39:214–23. [2] Winters Jr TF, Gage JR, Hicks R. Gait patterns in spastic hemiplegia in children and young adults. J Bone Joint Surg Am 1987;69:437–41.
doi:10.1016/j.gaitpost.2009.08.139 P20
Fig. 1. Average upright time and steps per day against number of STST.
The number of sit-to-stand transitions in relation to time upright and steps taken in children with cerebral palsy K. Tang 1,∗ , W. Spence 1 , D. Maxwell 3 , B. Stansfield 4
Simpson 1 , A.
Richardson 2 , D.
1
University of Strathclyde, Glasgow, United Kingdom Anderson Gait Laboratory, Astley Ainslie Hospital, Edinburgh, United Kingdom 3 PAL Technologies Ltd., Glasgow, United Kingdom 4 Glasgow Caledonian University, Glasgow, United Kingdom 2
Summary Objective measurement of physical activity (PA) provides insight into the effect of interventions on daily life. As yet there is no consensus as to which parameters are important. The relationship between the average free-living number of sit-to-stand transitions (STST) and upright time and steps taken (recorded by an accelerometer based monitor) was explored in subjects with cerebral palsy (CP). Conclusions Objective (accelerometer based) measurement of PA provides evidence of actual free-living mobility. The lack of a direct relationship between number of STST, upright time and steps taken indicates that some subjects performed only functional activity, whilst others performed additional voluntary PA. It is important to choose an appropriate outcome measure for PA assessment. Introduction Children with CP have a range of mobility impairments and it is important to document their PA to assess if interventions are helping to maintain an active lifestyle [1]. Although objective measures of PA have been available for a number of years, they are not used routinely as an outcome assessment in the population of children with CP. STST are an important part of functional requirement for independent living. This study objectively quantifies STST, illustrating the relationship with upright time and step count over multiday periods. Patients/materials and methods A multiday record of free-living PA of 15 children with CP was obtained using an activity monitor (activPAL, PAL Technologies Ltd.). PA was divided into periods spent sitting/lying or upright and walking identified within upright periods [2]. The average number of steps taken per day and the average time spent in the upright position were used as indicators of a subject’s PA level. The relationship between these variables and the number of STST was used to explore the quality of the free-living PA of subjects with CP.
Results Average number of STST for the 15 subjects with CP during freeliving monitoring against average upright time and step count per day are shown (Fig. 1). There were large variations in the average daily step count (642–14,808 steps per day), average upright times (0.89–5.47 h/day) and average number of STST (31–101). Discussion It appeared that there was a ‘threshold’ number of sit to stand transitions of approximately 40 per day, indicating functional task performance only. There were, however, four subjects who performed over twice this number indicating engagement with additional discretionary activity. No clear relationship between upright time, step count and STST was evident indicating a wide range of duration of upright periods. Categorisation of activity profile by clusters within this analysis may be appropriate for judging success of interventions in promoting PA above the requirements of fulfilling functional tasks only. References [1] Steenbergen, Gordon. Dev Med Child Neurol 2006;48:780–3. [2] Grant, et al. Br J Sports Med 2006;40:992–7.
doi:10.1016/j.gaitpost.2009.08.140 P21 Can stability in hemiplegic and asymmetric diplegic gait be determined by simple RPA calculation? Tam Nguyen 1 , Kelly Pinkney 1 , James Rice 2,∗ , Maria Crotty 1 1
South Australian Movement Analysis Centre - Repatriation General Hospital, Adelaide, SA, Australia 2 Paediatric Rehabilitation Service-Women’s and Children’s Hospital, Adelaide, SA, Australia Summary This study aimed to compare the inter-joint coordination pattern of children with CP to normal controls. The preliminary results showed that the pattern of relative phase angle (RPA) in the sagittal plane was similar in all groups, with minima and maxima of RPA phase lag or phase gain occurring at different timing intervals. Conclusions RPA showed differences in the inter-joint coordination between the groups, especially in the level of variability which warrants further investigation.
Abstracts / Gait & Posture 30S (2009) S1–S153
Introduction Relative phase angle (RPA) represents the phase relationships (the spatial and temporal coupling) of a pair of interacting joints during a movement [1]. The variability in the RPA provides information about the stability of the selected movement pattern. A low variability indicates a more stable relationship between the two joints. This technique has been used previously to explore joint coordination, such as the phase relationship between hip and knee joints [2] with critical implications on balance, joint loading and stability. This is especially applicable to children with cerebral palsy (CP), who do not move away from the immature pattern of synchronous hip and knee flexion and extension to dissociation between intra limb joints [3]. Patients/materials and methods Three groups of children are included in this study - Hemiplegia [n = 12; age = 12.5 (range 10–21)] and asymmetric diplegia [n = 8; age = 11.5 (range 8–16)] were compared with control children [n = 12, age = 9 (range 4–15)]. The two CP groups were classified as Level 1 or 2 on the Gross Motor Functional Classification Scale and could walk unaided and without orthotics over a 10 m distance. Gait data capture and analysis were performed using an 8 camera Vicon Mx3 3-D motion analysis system and associated software. RPA was used to quantify inter joint coordination of the following segment pairs: hip–knee (H–K) and knee–ankle (K–A). Results Fig. 1 shows the sagittal plane coordination plot averaged over all subjects for control (thickline), asymmetric diplegic (hatched) and hemiplegic subjects (dotted). Discussion The sagittal inter-joint coordination during gait in CP subjects is still largely unexplained, but is thought to be associated with some compensation mechanisms. The results from this study showed
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that the pattern of RPA in the sagittal plane was similar in all groups, with minima and maxima of RPA phase lag or phase gain occurring at different timing intervals. The CP group had higher inter-subject variability. This suggested there is a component of instability in their gait, despite their effort in the changes in temporal spatial parameters and kinematics to reduce this instability. The loading response and mid-stance phase for H–K’s RPA had the higher variability in the asymmetric group. Asymmetric group’s K–A RPA, show a phase lag, while the control and hemi both stayed in phase during the mid stance. The K–A also has a large difference in the terminal-swing phases between controls and the CP groups. This may be due to the coupling effect of the K–A segment. References [1] Wheat JS, Glazier PS. Movement system variability. In: Davids K, Bennett S, Newell K, editors. Human kinetics. 2006. [2] Burgess-Limerick, et al. Journal of Biomechanics 1993;26(1):91–4. [3] Farmer, et al. Gait and Posture 2008;28:217–21.
doi:10.1016/j.gaitpost.2009.08.141 P22 Influence of walking speed on gait characteristics in children with spastic cerebral palsy Kaat Desloovere 1,2,∗ , Kim Christiaens 2 , Deborah Severijns 2 , Leen Van Gestel 1 , Guy Molenaers 3,5 , Katrien Fagard 2 , Hans Wambacq 4 , Erwin Aertbeliën 4 , Herman Bruyninckx 4 1
Department of Rehabilitation Sciences (KUL), Leuven, Belgium Clinical Motion Analysis Laboratory CERM (University Hospital Pellenberg), Pellenberg, Belgium 3 Department of Musculoskeletal Sciences (KUL), Leuven, Belgium 4 Department of Mechanical Engineering (KUL), Leuven, Belgium 5 Department of Paediatric Orthopaedics, University of Pellenberg, Belgium 2
Summary Objective of the study was to explore differences between typically developing children (TDc) and cerebral palsy children (CPc) in adaptation strategies to higher gait speeds, by studying changes in kinematics, kinetics, muscle lengths and lengthening velocity. Conclusions Changes in gait patterns caused by increased walking speed were found to be different between TDc and CPc. Introduction Gait parameters in TDc are found to be related to speed [1,2]. In children with CP, increased speed may not only augment influence of spasticity, since spasticity is defined as a velocity dependent increase of muscle activity, but also increase pathological patterns related to higher demands of motor control. Patients, materials and methods 24 ambulant children with spastic CP (age 10.3 ± 2.3 years, GMFCS I–II, 14 hemi-10 diplegia) as well as 8 age-matched TDc were evaluated. Children were asked to walk at self-selected speed, then at self-selected faster speed and finally as fast as possible without running. All children received full gait analysis (lower limb kinematics including muscle lengths and kinetics). Speed changes in 40 gait parameters were compared between groups by Kruskal–Wallis and Wilcoxon test.
Fig. 1. Sagittal RPA: H–K and K–A.
Abstracts / Gait & Posture 30S (2009) S1–S153
relatively small talus and calcaneus makes the bones difficult to measure compared to the tibia. Whether the reason to discrepancy is caused by relative disuse, less muscle activity and loading on the hemiplegic side or is directly related to the brain injury is not clear. This limited study suggests a relation between degree of involvement in hemiplegic CP and location of leg length discrepancy. References [1] Palisano R. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol 1997;39:214–23. [2] Winters Jr TF, Gage JR, Hicks R. Gait patterns in spastic hemiplegia in children and young adults. J Bone Joint Surg Am 1987;69:437–41.
doi:10.1016/j.gaitpost.2009.08.139 P20
Fig. 1. Average upright time and steps per day against number of STST.
The number of sit-to-stand transitions in relation to time upright and steps taken in children with cerebral palsy K. Tang 1,∗ , W. Spence 1 , D. Maxwell 3 , B. Stansfield 4
Simpson 1 , A.
Richardson 2 , D.
1
University of Strathclyde, Glasgow, United Kingdom Anderson Gait Laboratory, Astley Ainslie Hospital, Edinburgh, United Kingdom 3 PAL Technologies Ltd., Glasgow, United Kingdom 4 Glasgow Caledonian University, Glasgow, United Kingdom 2
Summary Objective measurement of physical activity (PA) provides insight into the effect of interventions on daily life. As yet there is no consensus as to which parameters are important. The relationship between the average free-living number of sit-to-stand transitions (STST) and upright time and steps taken (recorded by an accelerometer based monitor) was explored in subjects with cerebral palsy (CP). Conclusions Objective (accelerometer based) measurement of PA provides evidence of actual free-living mobility. The lack of a direct relationship between number of STST, upright time and steps taken indicates that some subjects performed only functional activity, whilst others performed additional voluntary PA. It is important to choose an appropriate outcome measure for PA assessment. Introduction Children with CP have a range of mobility impairments and it is important to document their PA to assess if interventions are helping to maintain an active lifestyle [1]. Although objective measures of PA have been available for a number of years, they are not used routinely as an outcome assessment in the population of children with CP. STST are an important part of functional requirement for independent living. This study objectively quantifies STST, illustrating the relationship with upright time and step count over multiday periods. Patients/materials and methods A multiday record of free-living PA of 15 children with CP was obtained using an activity monitor (activPAL, PAL Technologies Ltd.). PA was divided into periods spent sitting/lying or upright and walking identified within upright periods [2]. The average number of steps taken per day and the average time spent in the upright position were used as indicators of a subject’s PA level. The relationship between these variables and the number of STST was used to explore the quality of the free-living PA of subjects with CP.
Results Average number of STST for the 15 subjects with CP during freeliving monitoring against average upright time and step count per day are shown (Fig. 1). There were large variations in the average daily step count (642–14,808 steps per day), average upright times (0.89–5.47 h/day) and average number of STST (31–101). Discussion It appeared that there was a ‘threshold’ number of sit to stand transitions of approximately 40 per day, indicating functional task performance only. There were, however, four subjects who performed over twice this number indicating engagement with additional discretionary activity. No clear relationship between upright time, step count and STST was evident indicating a wide range of duration of upright periods. Categorisation of activity profile by clusters within this analysis may be appropriate for judging success of interventions in promoting PA above the requirements of fulfilling functional tasks only. References [1] Steenbergen, Gordon. Dev Med Child Neurol 2006;48:780–3. [2] Grant, et al. Br J Sports Med 2006;40:992–7.
doi:10.1016/j.gaitpost.2009.08.140 P21 Can stability in hemiplegic and asymmetric diplegic gait be determined by simple RPA calculation? Tam Nguyen 1 , Kelly Pinkney 1 , James Rice 2,∗ , Maria Crotty 1 1
South Australian Movement Analysis Centre - Repatriation General Hospital, Adelaide, SA, Australia 2 Paediatric Rehabilitation Service-Women’s and Children’s Hospital, Adelaide, SA, Australia Summary This study aimed to compare the inter-joint coordination pattern of children with CP to normal controls. The preliminary results showed that the pattern of relative phase angle (RPA) in the sagittal plane was similar in all groups, with minima and maxima of RPA phase lag or phase gain occurring at different timing intervals. Conclusions RPA showed differences in the inter-joint coordination between the groups, especially in the level of variability which warrants further investigation.
Abstracts / Gait & Posture 30S (2009) S1–S153
Introduction Relative phase angle (RPA) represents the phase relationships (the spatial and temporal coupling) of a pair of interacting joints during a movement [1]. The variability in the RPA provides information about the stability of the selected movement pattern. A low variability indicates a more stable relationship between the two joints. This technique has been used previously to explore joint coordination, such as the phase relationship between hip and knee joints [2] with critical implications on balance, joint loading and stability. This is especially applicable to children with cerebral palsy (CP), who do not move away from the immature pattern of synchronous hip and knee flexion and extension to dissociation between intra limb joints [3]. Patients/materials and methods Three groups of children are included in this study - Hemiplegia [n = 12; age = 12.5 (range 10–21)] and asymmetric diplegia [n = 8; age = 11.5 (range 8–16)] were compared with control children [n = 12, age = 9 (range 4–15)]. The two CP groups were classified as Level 1 or 2 on the Gross Motor Functional Classification Scale and could walk unaided and without orthotics over a 10 m distance. Gait data capture and analysis were performed using an 8 camera Vicon Mx3 3-D motion analysis system and associated software. RPA was used to quantify inter joint coordination of the following segment pairs: hip–knee (H–K) and knee–ankle (K–A). Results Fig. 1 shows the sagittal plane coordination plot averaged over all subjects for control (thickline), asymmetric diplegic (hatched) and hemiplegic subjects (dotted). Discussion The sagittal inter-joint coordination during gait in CP subjects is still largely unexplained, but is thought to be associated with some compensation mechanisms. The results from this study showed
S95
that the pattern of RPA in the sagittal plane was similar in all groups, with minima and maxima of RPA phase lag or phase gain occurring at different timing intervals. The CP group had higher inter-subject variability. This suggested there is a component of instability in their gait, despite their effort in the changes in temporal spatial parameters and kinematics to reduce this instability. The loading response and mid-stance phase for H–K’s RPA had the higher variability in the asymmetric group. Asymmetric group’s K–A RPA, show a phase lag, while the control and hemi both stayed in phase during the mid stance. The K–A also has a large difference in the terminal-swing phases between controls and the CP groups. This may be due to the coupling effect of the K–A segment. References [1] Wheat JS, Glazier PS. Movement system variability. In: Davids K, Bennett S, Newell K, editors. Human kinetics. 2006. [2] Burgess-Limerick, et al. Journal of Biomechanics 1993;26(1):91–4. [3] Farmer, et al. Gait and Posture 2008;28:217–21.
doi:10.1016/j.gaitpost.2009.08.141 P22 Influence of walking speed on gait characteristics in children with spastic cerebral palsy Kaat Desloovere 1,2,∗ , Kim Christiaens 2 , Deborah Severijns 2 , Leen Van Gestel 1 , Guy Molenaers 3,5 , Katrien Fagard 2 , Hans Wambacq 4 , Erwin Aertbeliën 4 , Herman Bruyninckx 4 1
Department of Rehabilitation Sciences (KUL), Leuven, Belgium Clinical Motion Analysis Laboratory CERM (University Hospital Pellenberg), Pellenberg, Belgium 3 Department of Musculoskeletal Sciences (KUL), Leuven, Belgium 4 Department of Mechanical Engineering (KUL), Leuven, Belgium 5 Department of Paediatric Orthopaedics, University of Pellenberg, Belgium 2
Summary Objective of the study was to explore differences between typically developing children (TDc) and cerebral palsy children (CPc) in adaptation strategies to higher gait speeds, by studying changes in kinematics, kinetics, muscle lengths and lengthening velocity. Conclusions Changes in gait patterns caused by increased walking speed were found to be different between TDc and CPc. Introduction Gait parameters in TDc are found to be related to speed [1,2]. In children with CP, increased speed may not only augment influence of spasticity, since spasticity is defined as a velocity dependent increase of muscle activity, but also increase pathological patterns related to higher demands of motor control. Patients, materials and methods 24 ambulant children with spastic CP (age 10.3 ± 2.3 years, GMFCS I–II, 14 hemi-10 diplegia) as well as 8 age-matched TDc were evaluated. Children were asked to walk at self-selected speed, then at self-selected faster speed and finally as fast as possible without running. All children received full gait analysis (lower limb kinematics including muscle lengths and kinetics). Speed changes in 40 gait parameters were compared between groups by Kruskal–Wallis and Wilcoxon test.
Fig. 1. Sagittal RPA: H–K and K–A.