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Identification and quantification of muscle activation patterns in lower limb muscles of children with spastic cerebral palsy
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Abstracts / Gait & Posture 39S (2014) S1–S141
Fig. 1. (A) Isometric joint moment profile, (B) Isometric moment/kg profile and (C) Isokinetic power profile of healthy controls, unilateral and bilateral claudicants.
Noraxon) were examined from vastus medialis (VM), medial hamstrings (MH), and gastrocnemius medialis (GM). For each patient three gait cycles were analysed by means of on/off analysis. Principal Component Analysis (PCA) was used to compare transversal hip kinematic (8 cameras, VICON) between each patient group and 17 healthy, age-matched subjects in order to analyse possible influence on the electromyographic activity. Linear mixed models applied to PC-scores were used to determine the main effects within retained principal components (PCs). Results: An additional activity has been measured during the last 20% of the stance phase in 5 (VM) resp. 2 (MH) of 8 patients with increased TT and in 6 (VM) resp. 7 (MH) of 16 patients with decreased TT. The GM also showed an abnormal SEMG in terms of premature activity at the beginning and at the end of the gait cycle in a total of 13 patients. Hip transversal kinematic was not different between patients with decreased TT and healthy controls (hip PC1: 74.4%, p = .272) in this small sample. However, patients with increased TT rotated the hip significantly more internally during the overall gait cycle compared to the healthy control group (PC1: 72.5%, p < .001) (Fig. 1). Discussion and conclusion: In patients with excessive external or internal TT we could show that VM and MH work actively against the lever arm dysfunction of plantarflexors to support the extension of the knee and hip. In order to compensate for the external foot progression angle, patients with increased TT may also activate the MH to rotate the hip internally. Activity of gastrocnemius medialis has also been seen as a compensation of lever arm dysfunction. We conclude that patients with abnormal external or internal TT need to strengthen their quadriceps and hamstrings beside the plantar flexors in case of weakness of these muscles.
Reference [1] [2] [3] [4]
Chen, et al. J Biomech 2008;41:2506–14. Scott-Pandorf, et al. J Vasc Surg 2007;46:491–9. Celis, et al. J Vasc Surg 2009;49:127–32. Crowther, et al. J Vasc Surg 2007;45:1172–8.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.042 038 Compensatory muscle activation during walking in adolescents with excessive external and internal tibial torsion Regina Wegener 1,∗ , Erika Payne 2 , Katja Zdenek 2 , Harry Klima 2 , Verena Fenner 1 1
Children’s Hospital of Eastern Switzerland, Paediatric Orthopaedics, Laboratory for Motion Analysis, St. Gallen, Switzerland 2 Children’s Hospital of Eastern Switzerland, Paediatric Orthopaedics, St. Gallen, Switzerland Introduction and aim: In previous studies it has been postulated that excessive tibial torsion (TT) leads to a reduced ability of muscles to extend the knee due to lever arm dysfunction. This may contribute to crouch gait [1,2]. Although the soleus crosses the ankle joint it has also the potential to extend both the knee and the hip while working against gravity [1,3]. To date the effects of excessive external and internal TT on muscles which extend the stance limb during walking has not been investigated by SEMG. Patients/materials and methods: Gait analysis data of 8 patients (mean 13.2 yrs) and 11 legs resp. 16 patients (mean 12.3 yrs) and 23 legs with CT-diagnosed external (mean 49◦ ) and internal (mean 17◦ ) TT were studied retrospectively. Exclusion criteria were age <10 and >18 years, leg length discrepancy >1 cm, foot deformities, neurological diseases, scoliosis >10◦ and obesity (>PCTL 90). Bilateral SEMG signals (12-channel-wireless, 1000 Hz,
Reference [1] Hicks, et al. Gait Posture 2007;26:546–52. [2] Schwartz, et al. Gait Posture 2003;17:113–8. [3] Kimmel, Schwartz. Gait Posture 2006;23:211–21.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.043 039 Identification and quantification of muscle activation patterns in lower limb muscles of children with spastic cerebral palsy L. Bar-On 1,2,∗ , E. Aertbeliën 3 , G. Molenaers 1,4,5 , C. Huenaerts 1 , A. Van Campenhout 1,4,5 , K. Desloovere 1,2 1 Clinical Motion Analysis Laboratory, University Hospital Leuven, Belgium 2 KU Leuven, Department of Rehabilitation Sciences, Belgium 3 KU Leuven, Department of Mechanical Engineering, Belgium 4 KU Leuven, Department of Development and Regeneration, Belgium 5 Department of Orthopedics, University Hospital Leuven, Belgium
Introduction and aim: Lances’ (1980) definition of spasticity as a velocity-dependent activation of the tonic stretch reflex is the most widely accepted [1]. However, position-dependent muscle activation, which has been reported in patients with stroke [2] and spinal cord injury [3], has received little attention in children with cerebral palsy (CP). The aim of the study was to identify and quantify position and velocity-dependent muscle activation patterns in
Abstracts / Gait & Posture 39S (2014) S1–S141
S31
Fig. 1. Muscle activity of medial hamstrings (MH), vastus medialis (VM), and gastrocnemius medialis (GM) in patients with increased (left) and decreased (right) tibial torsion (black: physiological activity phase, grey: additional activity phase).
Fig. 1. Example of an VD (A) and a M-VD (B) muscle activation pattern in the MEH.
Table 1 Median (IQR) of RMS-EMGpos and RMS-EMGvel for the different activation patterns during low velocity stretches.
GAS (n) RMS-EMGpos (%) RMS-EMGvel (%) MEH (n) RMS-EMGpos (%) RMS-EMGvel (%)
VD
M-VD
M-PD
31 0.17 (0.99) 7.86 (5.49) 12 0.06 (0.29) 0.04 (0.09)
13 1.85 (2.81) 2.17 (5.13) 35 2.92 (6.71) 0.57 (2.10)
0 – – 8 11.85 (18.38) 4.73 (5.54)
p
VD ADD (n) RMS-EMGpos (%) RMS-EMGvel (%) REF (n) RMS-EMGpos (%) RMS-EMGvel (%)
<0.01 <0.01 <0.01 0.01
adductors (ADD), medial hamstrings (MEH), gastrocnemius (GAS) and rectus femoris (REF) in children with spastic CP. Patients/materials and methods: Forty-four GAS, 53 MEH, 28 ADD, and 34 REF muscles (n = 54; 10.8 ± 3.7 yrs; females n = 17; bilateral/unilateral involvement n = 30/24; GMFCS I–IV) were measured with an instrumented spasticity assessment [4]. Joint angle characteristics and root mean square electromyography (RMSEMG) were recorded during passive stretches at three incremental velocities. Three equal position zones across the full range of motion were defined. Average normalized RMS-EMG was compared across position zones (RMS-EMGpos) and increasing velocities (RMSEMGvel), see Fig. 1. Muscles were visually categorised (using RMS-EMG) into following activation patterns: velocity-dependent (VD), mixed more VD (M-VD), or mixed more PD (M-PD). Per muscle, RMS-EMGpos and RMS-EMGvel were compared between activation patterns using Kruskal–Wallis or Man–Whitney U tests. Results: VD and M-VD patterns were detected in all muscles (Table 1). M-PD was additionally found in MEH. In VD patterns, average normalized RMS-EMG only increased during medium and high velocity stretches (Fig. 1A). In mixed patterns, average normalized RMSEMG linearly increased with increasing angular position, at all three stretch velocities (Fig. 1B). Comparing averaged normalized RMS-EMG between position zones during low velocity
8 0.1 (06) 5.25 (5.71) 27 0.02 (0.35) 1.16 (25.02)
M-VD 20 2.6 (3.4) 9.86 (9.59) 7 7.48 (18.93) 0.02 (0.35)
M-PD 0 – – 0 – –
p <0.01 <0.01 <0.01 0.29
stretches proved most sensitive in automatically categorizing and quantifying muscles as VD, M-VD or M-PD (Table 1). Discussion and conclusions: Different activation patterns are present in lower limb muscles of children with spastic CP. While it is known that velocity-dependency dominates most patterns, we have found that position-dependency also has a significant contribution to increased muscle activation during passive stretch, especially in spastic MEH. Identification and quantification of both types of dependencies could further optimize treatment delineation. Future intervention studies should assess treatment effects on muscles with different activation patterns. Reference [1] [2] [3] [4]
Lance JW. Lancet 1990:335–606. Calota A, et al. Clin Neurophysiol 2008;119:2329–37. van der Salm A, et al. Arch Phys Med Rehabil 2005;86:1991–7. Bar-On L, et al. Gait Posture 2013;38:141–7.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.044
Abstracts / Gait & Posture 39S (2014) S1–S141
Fig. 1. (A) Isometric joint moment profile, (B) Isometric moment/kg profile and (C) Isokinetic power profile of healthy controls, unilateral and bilateral claudicants.
Noraxon) were examined from vastus medialis (VM), medial hamstrings (MH), and gastrocnemius medialis (GM). For each patient three gait cycles were analysed by means of on/off analysis. Principal Component Analysis (PCA) was used to compare transversal hip kinematic (8 cameras, VICON) between each patient group and 17 healthy, age-matched subjects in order to analyse possible influence on the electromyographic activity. Linear mixed models applied to PC-scores were used to determine the main effects within retained principal components (PCs). Results: An additional activity has been measured during the last 20% of the stance phase in 5 (VM) resp. 2 (MH) of 8 patients with increased TT and in 6 (VM) resp. 7 (MH) of 16 patients with decreased TT. The GM also showed an abnormal SEMG in terms of premature activity at the beginning and at the end of the gait cycle in a total of 13 patients. Hip transversal kinematic was not different between patients with decreased TT and healthy controls (hip PC1: 74.4%, p = .272) in this small sample. However, patients with increased TT rotated the hip significantly more internally during the overall gait cycle compared to the healthy control group (PC1: 72.5%, p < .001) (Fig. 1). Discussion and conclusion: In patients with excessive external or internal TT we could show that VM and MH work actively against the lever arm dysfunction of plantarflexors to support the extension of the knee and hip. In order to compensate for the external foot progression angle, patients with increased TT may also activate the MH to rotate the hip internally. Activity of gastrocnemius medialis has also been seen as a compensation of lever arm dysfunction. We conclude that patients with abnormal external or internal TT need to strengthen their quadriceps and hamstrings beside the plantar flexors in case of weakness of these muscles.
Reference [1] [2] [3] [4]
Chen, et al. J Biomech 2008;41:2506–14. Scott-Pandorf, et al. J Vasc Surg 2007;46:491–9. Celis, et al. J Vasc Surg 2009;49:127–32. Crowther, et al. J Vasc Surg 2007;45:1172–8.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.042 038 Compensatory muscle activation during walking in adolescents with excessive external and internal tibial torsion Regina Wegener 1,∗ , Erika Payne 2 , Katja Zdenek 2 , Harry Klima 2 , Verena Fenner 1 1
Children’s Hospital of Eastern Switzerland, Paediatric Orthopaedics, Laboratory for Motion Analysis, St. Gallen, Switzerland 2 Children’s Hospital of Eastern Switzerland, Paediatric Orthopaedics, St. Gallen, Switzerland Introduction and aim: In previous studies it has been postulated that excessive tibial torsion (TT) leads to a reduced ability of muscles to extend the knee due to lever arm dysfunction. This may contribute to crouch gait [1,2]. Although the soleus crosses the ankle joint it has also the potential to extend both the knee and the hip while working against gravity [1,3]. To date the effects of excessive external and internal TT on muscles which extend the stance limb during walking has not been investigated by SEMG. Patients/materials and methods: Gait analysis data of 8 patients (mean 13.2 yrs) and 11 legs resp. 16 patients (mean 12.3 yrs) and 23 legs with CT-diagnosed external (mean 49◦ ) and internal (mean 17◦ ) TT were studied retrospectively. Exclusion criteria were age <10 and >18 years, leg length discrepancy >1 cm, foot deformities, neurological diseases, scoliosis >10◦ and obesity (>PCTL 90). Bilateral SEMG signals (12-channel-wireless, 1000 Hz,
Reference [1] Hicks, et al. Gait Posture 2007;26:546–52. [2] Schwartz, et al. Gait Posture 2003;17:113–8. [3] Kimmel, Schwartz. Gait Posture 2006;23:211–21.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.043 039 Identification and quantification of muscle activation patterns in lower limb muscles of children with spastic cerebral palsy L. Bar-On 1,2,∗ , E. Aertbeliën 3 , G. Molenaers 1,4,5 , C. Huenaerts 1 , A. Van Campenhout 1,4,5 , K. Desloovere 1,2 1 Clinical Motion Analysis Laboratory, University Hospital Leuven, Belgium 2 KU Leuven, Department of Rehabilitation Sciences, Belgium 3 KU Leuven, Department of Mechanical Engineering, Belgium 4 KU Leuven, Department of Development and Regeneration, Belgium 5 Department of Orthopedics, University Hospital Leuven, Belgium
Introduction and aim: Lances’ (1980) definition of spasticity as a velocity-dependent activation of the tonic stretch reflex is the most widely accepted [1]. However, position-dependent muscle activation, which has been reported in patients with stroke [2] and spinal cord injury [3], has received little attention in children with cerebral palsy (CP). The aim of the study was to identify and quantify position and velocity-dependent muscle activation patterns in
Abstracts / Gait & Posture 39S (2014) S1–S141
S31
Fig. 1. Muscle activity of medial hamstrings (MH), vastus medialis (VM), and gastrocnemius medialis (GM) in patients with increased (left) and decreased (right) tibial torsion (black: physiological activity phase, grey: additional activity phase).
Fig. 1. Example of an VD (A) and a M-VD (B) muscle activation pattern in the MEH.
Table 1 Median (IQR) of RMS-EMGpos and RMS-EMGvel for the different activation patterns during low velocity stretches.
GAS (n) RMS-EMGpos (%) RMS-EMGvel (%) MEH (n) RMS-EMGpos (%) RMS-EMGvel (%)
VD
M-VD
M-PD
31 0.17 (0.99) 7.86 (5.49) 12 0.06 (0.29) 0.04 (0.09)
13 1.85 (2.81) 2.17 (5.13) 35 2.92 (6.71) 0.57 (2.10)
0 – – 8 11.85 (18.38) 4.73 (5.54)
p
VD ADD (n) RMS-EMGpos (%) RMS-EMGvel (%) REF (n) RMS-EMGpos (%) RMS-EMGvel (%)
<0.01 <0.01 <0.01 0.01
adductors (ADD), medial hamstrings (MEH), gastrocnemius (GAS) and rectus femoris (REF) in children with spastic CP. Patients/materials and methods: Forty-four GAS, 53 MEH, 28 ADD, and 34 REF muscles (n = 54; 10.8 ± 3.7 yrs; females n = 17; bilateral/unilateral involvement n = 30/24; GMFCS I–IV) were measured with an instrumented spasticity assessment [4]. Joint angle characteristics and root mean square electromyography (RMSEMG) were recorded during passive stretches at three incremental velocities. Three equal position zones across the full range of motion were defined. Average normalized RMS-EMG was compared across position zones (RMS-EMGpos) and increasing velocities (RMSEMGvel), see Fig. 1. Muscles were visually categorised (using RMS-EMG) into following activation patterns: velocity-dependent (VD), mixed more VD (M-VD), or mixed more PD (M-PD). Per muscle, RMS-EMGpos and RMS-EMGvel were compared between activation patterns using Kruskal–Wallis or Man–Whitney U tests. Results: VD and M-VD patterns were detected in all muscles (Table 1). M-PD was additionally found in MEH. In VD patterns, average normalized RMS-EMG only increased during medium and high velocity stretches (Fig. 1A). In mixed patterns, average normalized RMSEMG linearly increased with increasing angular position, at all three stretch velocities (Fig. 1B). Comparing averaged normalized RMS-EMG between position zones during low velocity
8 0.1 (06) 5.25 (5.71) 27 0.02 (0.35) 1.16 (25.02)
M-VD 20 2.6 (3.4) 9.86 (9.59) 7 7.48 (18.93) 0.02 (0.35)
M-PD 0 – – 0 – –
p <0.01 <0.01 <0.01 0.29
stretches proved most sensitive in automatically categorizing and quantifying muscles as VD, M-VD or M-PD (Table 1). Discussion and conclusions: Different activation patterns are present in lower limb muscles of children with spastic CP. While it is known that velocity-dependency dominates most patterns, we have found that position-dependency also has a significant contribution to increased muscle activation during passive stretch, especially in spastic MEH. Identification and quantification of both types of dependencies could further optimize treatment delineation. Future intervention studies should assess treatment effects on muscles with different activation patterns. Reference [1] [2] [3] [4]
Lance JW. Lancet 1990:335–606. Calota A, et al. Clin Neurophysiol 2008;119:2329–37. van der Salm A, et al. Arch Phys Med Rehabil 2005;86:1991–7. Bar-On L, et al. Gait Posture 2013;38:141–7.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.044