The influence of maximum isometric muscle force scaling on estimated muscle forces from musculoskeletal models of children with cerebral palsy

Publication date: Available online 22 July 2018

Source: Gait & Posture

Author(s): Hans Kainz, Marije Goudriaan, Antoine Falisse, Catherine Huenaerts, Kaat Desloovere, Friedl De Groote, Ilse Jonkers

Abstract

Background

Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance in order to represent each child's compensation mechanisms introduced through muscle weakness.

Research aim

The aims of this study were to (i) evaluate if maximum isometric muscle forces (MIMF) in musculoskeletal models of children with CP can be scaled based on strength measurements obtained with a hand-held-dynamometer (HHD), (ii) evaluate the impact of the HHD based scaling approach and previously published MIMF scaling methods on computed muscle forces during gait, and (iii) compare maximum muscle forces during gait between CP and TD children.

Methods

Strength and motion capture data of six CP and motion capture data of six TD children were collected. The HHD measurements to obtain hip, knee and ankle muscle strength were simulated in OpenSim and used to modify MIMF of the 2392-OpenSim model. These muscle forces were compared to the MIMF scaled on the child’s body mass and a scaling approach, which included the body mass and muscle-tendon lengths. OpenSim was used to calculate peak muscle forces during gait.

Results

Ankle muscle strength was insufficient to reproduce joint moments during walking when MIMF were scaled based on HHD. During gait, peak hip and knee extensor muscle forces were higher and peak ankle dorsi-flexor forces were lower in CP compared to TD participants.

Significance

HHD measurements can be used to scale MIMF for the hip and knee muscle groups but underestimate the force capacity of the ankle muscle groups during walking. Muscle-tendon-length and mass based scaling methods affected muscle activations but had little influence on peak muscle forces during gait.

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Effects of backward-downhill treadmill training versus manual static plantarflexor stretching on muscle-joint pathology and function in children with spastic Cerebral Palsy

Publication date: Available online 22 July 2018

Source: Gait & Posture

Author(s): Matthias Hösl, Harald Böhm, Justine Eck, Leonhard Döderlein, Adamantios Arampatzis

Abstract

Background

Patients with spastic Cerebral Palsy are prone to equinus deformities, likely affected by short and inextensible plantarflexor muscles. Manual stretching is a popular treatment but its effectiveness concerning joint mobility, muscle-tendon morphometrics and walking function is debated. Eccentric exercise by backward-downhill treadmill training could be a therapeutic alternative for ambulatory patients improving gait and muscle function.

Research question

What are the effects of eccentric training by backward-downhill treadmill training and plantarflexor stretching concerning gait and muscle function in patients with spastic Cerebral Palsy?

Methods

10 independent ambulators with spastic Cerebral Palsy (12 [SD 4] years old, 2 uni- and 8 bilaterally affected) participated in a randomized crossover-study. One group started with manual static stretching, the other one with backward-downhill treadmill training. Each treatment period lasted 9 weeks (3 sessions per week). Pre and post treatments, 3D gait was assessed during comfortable and during fastest possible walking. Ultrasonography and dynamometry were used to test plantarflexor strength, passive joint flexibility, as well as gastrocnemius morphometrics, stiffness and strain on muscle-tendon and joint level.

Results

When comparing both treatments, backward-downhill treadmill training lead to larger single stance dorsiflexion at comfortable walking speed (+2.9°, P = 0.041) and faster maximally achievable walking velocities ( + 0.10 m/s, P = 0.017). Stretching reduced knee flexion in swing, particularly at faster walking velocities (-5.4°, P = 0.003). Strength, ankle joint flexibility, as well as stiffness on muscle-tendon and joint level were not altered, despite similar increases in passive muscle and fascicle strain with both treatments (P ≤ 0.023).

Significance

Backward-downhill treadmill training can be an effective gait treatment, probably improving coordination or reducing dynamic stretch sensitivity. More intense BDTT might be necessary to further alter muscle-tendon properties. Manual static plantarflexor stretching may not be optimal in Cerebral Palsy patients with high ambulatory status.

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The influence of maximum isometric muscle force scaling on estimated muscle forces from musculoskeletal models of children with cerebral palsy

Publication date: Available online 22 July 2018

Source: Gait & Posture

Author(s): Hans Kainz, Marije Goudriaan, Antoine Falisse, Catherine Huenaerts, Kaat Desloovere, Friedl De Groote, Ilse Jonkers

Abstract

Background

Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance in order to represent each child's compensation mechanisms introduced through muscle weakness.

Research aim

The aims of this study were to (i) evaluate if maximum isometric muscle forces (MIMF) in musculoskeletal models of children with CP can be scaled based on strength measurements obtained with a hand-held-dynamometer (HHD), (ii) evaluate the impact of the HHD based scaling approach and previously published MIMF scaling methods on computed muscle forces during gait, and (iii) compare maximum muscle forces during gait between CP and TD children.

Methods

Strength and motion capture data of six CP and motion capture data of six TD children were collected. The HHD measurements to obtain hip, knee and ankle muscle strength were simulated in OpenSim and used to modify MIMF of the 2392-OpenSim model. These muscle forces were compared to the MIMF scaled on the child’s body mass and a scaling approach, which included the body mass and muscle-tendon lengths. OpenSim was used to calculate peak muscle forces during gait.

Results

Ankle muscle strength was insufficient to reproduce joint moments during walking when MIMF were scaled based on HHD. During gait, peak hip and knee extensor muscle forces were higher and peak ankle dorsi-flexor forces were lower in CP compared to TD participants.

Significance

HHD measurements can be used to scale MIMF for the hip and knee muscle groups but underestimate the force capacity of the ankle muscle groups during walking. Muscle-tendon-length and mass based scaling methods affected muscle activations but had little influence on peak muscle forces during gait.

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Effects of backward-downhill treadmill training versus manual static plantarflexor stretching on muscle-joint pathology and function in children with spastic Cerebral Palsy

Publication date: Available online 22 July 2018

Source: Gait & Posture

Author(s): Matthias Hösl, Harald Böhm, Justine Eck, Leonhard Döderlein, Adamantios Arampatzis

Abstract

Background

Patients with spastic Cerebral Palsy are prone to equinus deformities, likely affected by short and inextensible plantarflexor muscles. Manual stretching is a popular treatment but its effectiveness concerning joint mobility, muscle-tendon morphometrics and walking function is debated. Eccentric exercise by backward-downhill treadmill training could be a therapeutic alternative for ambulatory patients improving gait and muscle function.

Research question

What are the effects of eccentric training by backward-downhill treadmill training and plantarflexor stretching concerning gait and muscle function in patients with spastic Cerebral Palsy?

Methods

10 independent ambulators with spastic Cerebral Palsy (12 [SD 4] years old, 2 uni- and 8 bilaterally affected) participated in a randomized crossover-study. One group started with manual static stretching, the other one with backward-downhill treadmill training. Each treatment period lasted 9 weeks (3 sessions per week). Pre and post treatments, 3D gait was assessed during comfortable and during fastest possible walking. Ultrasonography and dynamometry were used to test plantarflexor strength, passive joint flexibility, as well as gastrocnemius morphometrics, stiffness and strain on muscle-tendon and joint level.

Results

When comparing both treatments, backward-downhill treadmill training lead to larger single stance dorsiflexion at comfortable walking speed (+2.9°, P = 0.041) and faster maximally achievable walking velocities ( + 0.10 m/s, P = 0.017). Stretching reduced knee flexion in swing, particularly at faster walking velocities (-5.4°, P = 0.003). Strength, ankle joint flexibility, as well as stiffness on muscle-tendon and joint level were not altered, despite similar increases in passive muscle and fascicle strain with both treatments (P ≤ 0.023).

Significance

Backward-downhill treadmill training can be an effective gait treatment, probably improving coordination or reducing dynamic stretch sensitivity. More intense BDTT might be necessary to further alter muscle-tendon properties. Manual static plantarflexor stretching may not be optimal in Cerebral Palsy patients with high ambulatory status.

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Prevalence of TECTA mutation in patients with mid-frequency sensorineural hearing loss.

Related Articles

Prevalence of TECTA mutation in patients with mid-frequency sensorineural hearing loss.

Orphanet J Rare Dis. 2017 09 25;12(1):157

Authors: Yamamoto N, Mutai H, Namba K, Morita N, Masuda S, Nishi Y, Nakano A, Masuda S, Fujioka M, Kaga K, Ogawa K, Matsunaga T

Abstract
BACKGROUND: To date, 102 genes have been reported as responsible for non-syndromic hearing loss, some of which are associated with specific audiogram features. Four genes have been reported as causative for mid-frequency sensorineural hearing loss (MFSNHL), among which TECTA is the most frequently reported; however, the prevalence of TECTA mutations is unknown. To elucidate the prevalence of TECTA mutation in MFSNHL and clarify genotype-phenotype correlations, we analyzed the genetic and clinical features of patients with MFSNHL.
METHODS: Subjects with bilateral non-syndromic hearing loss were prescreened for GJB2 and m.1555A > G and m.3243A > G mitochondrial DNA mutations, and patients with inner ear malformations were excluded. We selected MFSNHL patients whose audiograms met the U-shaped criterion proposed by the GENDEAF study group, along with those with shallow U-shaped audiograms, for TECTA analysis. All TECTA exons were analyzed by Sanger sequencing. Novel missense variants were classified as possibly pathogenic, non-pathogenic, and variants of uncertain significance, based on genetic data. To evaluate novel possibly pathogenic variants, we predicted changes in protein structure by molecular modeling.
RESULTS: Pathogenic and possibly pathogenic variants of TECTA were found in 4 (6.0%) of 67 patients with MFSNHL. In patients with U-shaped audiograms, none (0%) of 21 had pathogenic or possibly pathogenic variants. In patients with shallow U-shaped audiograms, four (8.7%) of 46 had pathogenic or possibly pathogenic variants. Two novel possibly pathogenic variants were identified and two previously reported mutations were considered as variant of unknown significance. The clinical features of patients with pathogenic and possibly pathogenic variants were consistent with those in previous studies. Pathogenic or possibly pathogenic variants were identified in 3 of 23 families (13.0%) which have the family histories compatible with autosomal dominant and 1 of 44 families (2.3%) which have the family histories compatible with sporadic or autosomal recessive.
CONCLUSIONS: TECTA mutations were identified in 6.0% of MFSNHL. These mutations were more frequent in patients with shallow U-shaped audiograms than those with U-shaped audiograms, and in families which have the family histories compatible with autosomal dominant than those with the family histories compatible with sporadic or autosomal recessive.

PMID: 28946916 [PubMed - indexed for MEDLINE]

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Prevalence of TECTA mutation in patients with mid-frequency sensorineural hearing loss.

Related Articles

Prevalence of TECTA mutation in patients with mid-frequency sensorineural hearing loss.

Orphanet J Rare Dis. 2017 09 25;12(1):157

Authors: Yamamoto N, Mutai H, Namba K, Morita N, Masuda S, Nishi Y, Nakano A, Masuda S, Fujioka M, Kaga K, Ogawa K, Matsunaga T

Abstract
BACKGROUND: To date, 102 genes have been reported as responsible for non-syndromic hearing loss, some of which are associated with specific audiogram features. Four genes have been reported as causative for mid-frequency sensorineural hearing loss (MFSNHL), among which TECTA is the most frequently reported; however, the prevalence of TECTA mutations is unknown. To elucidate the prevalence of TECTA mutation in MFSNHL and clarify genotype-phenotype correlations, we analyzed the genetic and clinical features of patients with MFSNHL.
METHODS: Subjects with bilateral non-syndromic hearing loss were prescreened for GJB2 and m.1555A > G and m.3243A > G mitochondrial DNA mutations, and patients with inner ear malformations were excluded. We selected MFSNHL patients whose audiograms met the U-shaped criterion proposed by the GENDEAF study group, along with those with shallow U-shaped audiograms, for TECTA analysis. All TECTA exons were analyzed by Sanger sequencing. Novel missense variants were classified as possibly pathogenic, non-pathogenic, and variants of uncertain significance, based on genetic data. To evaluate novel possibly pathogenic variants, we predicted changes in protein structure by molecular modeling.
RESULTS: Pathogenic and possibly pathogenic variants of TECTA were found in 4 (6.0%) of 67 patients with MFSNHL. In patients with U-shaped audiograms, none (0%) of 21 had pathogenic or possibly pathogenic variants. In patients with shallow U-shaped audiograms, four (8.7%) of 46 had pathogenic or possibly pathogenic variants. Two novel possibly pathogenic variants were identified and two previously reported mutations were considered as variant of unknown significance. The clinical features of patients with pathogenic and possibly pathogenic variants were consistent with those in previous studies. Pathogenic or possibly pathogenic variants were identified in 3 of 23 families (13.0%) which have the family histories compatible with autosomal dominant and 1 of 44 families (2.3%) which have the family histories compatible with sporadic or autosomal recessive.
CONCLUSIONS: TECTA mutations were identified in 6.0% of MFSNHL. These mutations were more frequent in patients with shallow U-shaped audiograms than those with U-shaped audiograms, and in families which have the family histories compatible with autosomal dominant than those with the family histories compatible with sporadic or autosomal recessive.

PMID: 28946916 [PubMed - indexed for MEDLINE]

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P 153 - Variability of gait parameters in children: The importance of normative data establishment

Publication date: Available online 21 July 2018

Source: Gait & Posture

Author(s): F. Joao, V. Bagao, S. Cabral, A. Veloso

Abstract

The aim of this study was to initiate the development of a database with the normative gait fundamental biomechanical parameters of a healthy pediatric population for the Laboratório de Biomecânica e Morfologia Funcional. Twenty-seven children cleared for neurological and musculoskeletal impairments, aged between seven and nine years old joined this study. From those twenty-seven, eleven completed a test-retest study with a median interval of seven days. Anthropometric, time-distance and peak values for the lower limb kinematic parameters were computed. The Interclass Correlation Coefficient (ICC) and the Standard Error of Measurement (SEM) were calculated for the kinematic parameters. Eight variables revealed SEM values between 2° and 5°, while all others were below 2°. Higher SEM was found for the variables Cadence (3.64 steps/min), Mean Value of Pelvic Tilt (2.48°), Maximum Hip Angle (2.56°), Minimum Hip angle (4.94°), Knee Angle at Initial Contact (2.40°), and Ankle ROM (2.79°). The MDC was below 6º in most of the variables.

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P 153 - Variability of gait parameters in children: The importance of normative data establishment

Publication date: Available online 21 July 2018

Source: Gait & Posture

Author(s): F. Joao, V. Bagao, S. Cabral, A. Veloso

Abstract

The aim of this study was to initiate the development of a database with the normative gait fundamental biomechanical parameters of a healthy pediatric population for the Laboratório de Biomecânica e Morfologia Funcional. Twenty-seven children cleared for neurological and musculoskeletal impairments, aged between seven and nine years old joined this study. From those twenty-seven, eleven completed a test-retest study with a median interval of seven days. Anthropometric, time-distance and peak values for the lower limb kinematic parameters were computed. The Interclass Correlation Coefficient (ICC) and the Standard Error of Measurement (SEM) were calculated for the kinematic parameters. Eight variables revealed SEM values between 2° and 5°, while all others were below 2°. Higher SEM was found for the variables Cadence (3.64 steps/min), Mean Value of Pelvic Tilt (2.48°), Maximum Hip Angle (2.56°), Minimum Hip angle (4.94°), Knee Angle at Initial Contact (2.40°), and Ankle ROM (2.79°). The MDC was below 6º in most of the variables.

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