Pieter Meyns | Universiteit Hasselt (original) (raw)
Papers by Pieter Meyns
Spinal cord, 2014
Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyog... more Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) ...
Gait & posture
Humans walk bipedally, and thus, it is unclear why they swing their arms. In this paper, we will ... more Humans walk bipedally, and thus, it is unclear why they swing their arms. In this paper, we will review the mechanisms and functions of arm swinging in human gait. First, we discuss the potential advantages of having swinging arms. Second, we go into the detail on the debate whether arm swing is arising actively or passively, where we will conclude that while a large part of arm swinging is mechanically passive, there is an active contribution of muscles (i.e. an activity that is not merely caused by stretch reflexes). Third, we describe the possible function of the active muscular contribution to arm swinging in normal gait, and discuss the possibility that a Central Pattern Generator (CPG) generates this activity. Fourth, we discuss examples from pathological cases, in which arm swinging is affected. Moreover, using the ideas presented, we suggest ways in which arm swing may be used as a therapeutic aid. We conclude that (1) arm swing should be seen as an integral part of human bi...
Oxford Textbook of Neurorehabilitation, 2015
Spinal cord, 2014
Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyog... more Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) ...
PLoS ONE
Previous studies comparing forward (FW) and backward (BW) walking suggested that the leg kinemati... more Previous studies comparing forward (FW) and backward (BW) walking suggested that the leg kinematics in BW were essentially those of FW in reverse. This led to the proposition that in adults the neural control of FW and BW originates from the same basic neural circuitry. One aspect that has not received much attention is to what extent development plays a role in the maturation of neural control of gait in different directions. BW has been examined either in adults or infants younger than one year. Therefore, we questioned which changes occur in the intermediate phases (i.e. in primary school-aged children). Furthermore, previous research focused on the lower limbs, thereby raising the question whether upper limb kinematics are also simply reversed from FW to BW. Therefore, in the current study the emphasis was put both on upper and lower limb movements, and the coordination between the limbs. Total body 3D gait analysis was performed in primary school-aged children (N = 24, aged fiv...
INTRODUCTION: In studies exploring the interaction between upper and lower limbs it was found tha... more INTRODUCTION: In studies exploring the interaction between upper and lower limbs it was found that Soleus H-reflexes are suppressed by rhythmic arm movements[1-4]. Furthermore in some of these studies[2,3] it was shown that there was a phase-dependent modulation of the ...
The purpose of this study was to investigate the effect of gait direction reversal on the contrib... more The purpose of this study was to investigate the effect of gait direction reversal on the contribution of muscles to the acceleration of the body mass center. Three-dimensional kinematics, ground reaction forces and electromyographic (EMG) activity was measured during a forward and backward walking trial of one subject. A perturbation analysis was used to compute the contributions of individual muscles to the horizontal acceleration of the body mass center. Our results indicate that muscles responsible for acceleration in forward walking also decelerate backward walking, whereas muscles that impede progression in the forward condition, are contributing to the acceleration in the backward movement. These results seem to support the hypothesis that similar muscle groups control progression in both forward and backward walking.
... To calculate arm swing length, first the finger marker was projected on the sagittal plane. A... more ... To calculate arm swing length, first the finger marker was projected on the sagittal plane. Arm swing length was then determined as the difference of maximum and minimum displacement of the finger marker along the x-axis (corrected for forward motion). ...
Journal of Neuroscience, 2014
It has been proposed that the cerebellum uses internal forward models to predict sensory conseque... more It has been proposed that the cerebellum uses internal forward models to predict sensory consequences of particular actions (Wolpert and Flanagan, 2001). This allows movements to be corrected when necessary. In addition to its paramount role in the control of movements, the cerebellum is also involved in sensory processing and perception, but there is no straightforward evidence for the cerebellum's involvement in the integration of action and perception. Therefore, a recent study in The Journal of Neuroscience set out to investigate the role of the cerebellum in action-perception coupling. Specifically, Christensen et al. (2014) studied patients with focal cerebellar lesions and healthy controls in a paradigm that measures the effect of motor execution on visual action perception.
Research in Developmental Disabilities, 2011
Research in Developmental Disabilities, 2013
Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaire... more Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE's sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (≈ 1.5 cm), while effects of walking speed (≈ 20 cm per m/s increase in walking speed) and group (≈ 5 cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP.
Research in Developmental Disabilities, 2012
The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded dur... more The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded during 3D gait analysis (3DGA), for the evaluation of functional muscle strength in children with cerebral palsy (CP). As walking velocity is known to also influence EMG frequency, it was investigated to which extent the mean EMG frequency is a reflection of underlying muscle strength and/or the applied walking velocity. Surface EMG data of the lateral gastrocnemius (LGAS) and medial hamstrings (MEH) were collected during 3DGA. For each muscle, 20 CP children characterized by a weak and 20 characterized by a strong muscle (LGAS or MEH) were selected. A weak muscle was defined as a manual muscle testing score <3; a strong muscle was defined as a manual muscle testing score ≥4. Patient selection was based on the following inclusion criteria: (a) predominantly spastic type of CP (3-15 years old), (b) either (near) normal muscle strength or muscle weakness in at least one of the studied lower limb muscles, (c) no lower limb Botulinum Toxin-A treatment within 6 months prior to the 3DGA, (d) no history of lower limb surgery, and (e) high-quality noise-free EMG-data. For each muscle, twenty age-related typically developing (TD) children were included as controls. In both muscles a consistent pattern of increasing mean EMG frequency with decreasing muscle strength was observed. This was significant in the LGAS (TD versus weak CP). Walking velocity also had a significant effect on mean EMG frequency in the LGAS. Furthermore, based on R(2) and partial correlations, it could be concluded that both walking velocity and muscle strength have an impact on EMG, but the contribution of muscle strength was always higher. These findings underscore the potential of the mean EMG frequency recorded during 3DGA, for the evaluation of functional muscle strength in children with CP.
Spinal cord, 2014
Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyog... more Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) ...
Gait & posture
Humans walk bipedally, and thus, it is unclear why they swing their arms. In this paper, we will ... more Humans walk bipedally, and thus, it is unclear why they swing their arms. In this paper, we will review the mechanisms and functions of arm swinging in human gait. First, we discuss the potential advantages of having swinging arms. Second, we go into the detail on the debate whether arm swing is arising actively or passively, where we will conclude that while a large part of arm swinging is mechanically passive, there is an active contribution of muscles (i.e. an activity that is not merely caused by stretch reflexes). Third, we describe the possible function of the active muscular contribution to arm swinging in normal gait, and discuss the possibility that a Central Pattern Generator (CPG) generates this activity. Fourth, we discuss examples from pathological cases, in which arm swinging is affected. Moreover, using the ideas presented, we suggest ways in which arm swing may be used as a therapeutic aid. We conclude that (1) arm swing should be seen as an integral part of human bi...
Oxford Textbook of Neurorehabilitation, 2015
Spinal cord, 2014
Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyog... more Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) ...
PLoS ONE
Previous studies comparing forward (FW) and backward (BW) walking suggested that the leg kinemati... more Previous studies comparing forward (FW) and backward (BW) walking suggested that the leg kinematics in BW were essentially those of FW in reverse. This led to the proposition that in adults the neural control of FW and BW originates from the same basic neural circuitry. One aspect that has not received much attention is to what extent development plays a role in the maturation of neural control of gait in different directions. BW has been examined either in adults or infants younger than one year. Therefore, we questioned which changes occur in the intermediate phases (i.e. in primary school-aged children). Furthermore, previous research focused on the lower limbs, thereby raising the question whether upper limb kinematics are also simply reversed from FW to BW. Therefore, in the current study the emphasis was put both on upper and lower limb movements, and the coordination between the limbs. Total body 3D gait analysis was performed in primary school-aged children (N = 24, aged fiv...
INTRODUCTION: In studies exploring the interaction between upper and lower limbs it was found tha... more INTRODUCTION: In studies exploring the interaction between upper and lower limbs it was found that Soleus H-reflexes are suppressed by rhythmic arm movements[1-4]. Furthermore in some of these studies[2,3] it was shown that there was a phase-dependent modulation of the ...
The purpose of this study was to investigate the effect of gait direction reversal on the contrib... more The purpose of this study was to investigate the effect of gait direction reversal on the contribution of muscles to the acceleration of the body mass center. Three-dimensional kinematics, ground reaction forces and electromyographic (EMG) activity was measured during a forward and backward walking trial of one subject. A perturbation analysis was used to compute the contributions of individual muscles to the horizontal acceleration of the body mass center. Our results indicate that muscles responsible for acceleration in forward walking also decelerate backward walking, whereas muscles that impede progression in the forward condition, are contributing to the acceleration in the backward movement. These results seem to support the hypothesis that similar muscle groups control progression in both forward and backward walking.
... To calculate arm swing length, first the finger marker was projected on the sagittal plane. A... more ... To calculate arm swing length, first the finger marker was projected on the sagittal plane. Arm swing length was then determined as the difference of maximum and minimum displacement of the finger marker along the x-axis (corrected for forward motion). ...
Journal of Neuroscience, 2014
It has been proposed that the cerebellum uses internal forward models to predict sensory conseque... more It has been proposed that the cerebellum uses internal forward models to predict sensory consequences of particular actions (Wolpert and Flanagan, 2001). This allows movements to be corrected when necessary. In addition to its paramount role in the control of movements, the cerebellum is also involved in sensory processing and perception, but there is no straightforward evidence for the cerebellum's involvement in the integration of action and perception. Therefore, a recent study in The Journal of Neuroscience set out to investigate the role of the cerebellum in action-perception coupling. Specifically, Christensen et al. (2014) studied patients with focal cerebellar lesions and healthy controls in a paradigm that measures the effect of motor execution on visual action perception.
Research in Developmental Disabilities, 2011
Research in Developmental Disabilities, 2013
Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaire... more Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE's sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (≈ 1.5 cm), while effects of walking speed (≈ 20 cm per m/s increase in walking speed) and group (≈ 5 cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP.
Research in Developmental Disabilities, 2012
The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded dur... more The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded during 3D gait analysis (3DGA), for the evaluation of functional muscle strength in children with cerebral palsy (CP). As walking velocity is known to also influence EMG frequency, it was investigated to which extent the mean EMG frequency is a reflection of underlying muscle strength and/or the applied walking velocity. Surface EMG data of the lateral gastrocnemius (LGAS) and medial hamstrings (MEH) were collected during 3DGA. For each muscle, 20 CP children characterized by a weak and 20 characterized by a strong muscle (LGAS or MEH) were selected. A weak muscle was defined as a manual muscle testing score <3; a strong muscle was defined as a manual muscle testing score ≥4. Patient selection was based on the following inclusion criteria: (a) predominantly spastic type of CP (3-15 years old), (b) either (near) normal muscle strength or muscle weakness in at least one of the studied lower limb muscles, (c) no lower limb Botulinum Toxin-A treatment within 6 months prior to the 3DGA, (d) no history of lower limb surgery, and (e) high-quality noise-free EMG-data. For each muscle, twenty age-related typically developing (TD) children were included as controls. In both muscles a consistent pattern of increasing mean EMG frequency with decreasing muscle strength was observed. This was significant in the LGAS (TD versus weak CP). Walking velocity also had a significant effect on mean EMG frequency in the LGAS. Furthermore, based on R(2) and partial correlations, it could be concluded that both walking velocity and muscle strength have an impact on EMG, but the contribution of muscle strength was always higher. These findings underscore the potential of the mean EMG frequency recorded during 3DGA, for the evaluation of functional muscle strength in children with CP.