Extensor Thrust Research Articles

Long-term repeated botulinum toxin a treatment over 12 years gradually changes gait characteristics: single-case study

Objective: To demonstrate the long-term efficacy of repeated botulinum toxin A injections into the same muscles for ameliorating lower limb spasticity and gait function. Design: Single-case study Patient: A 36-year-old woman with right cerebral haemorrhage received her first botulinum toxin A injection 1,296 days after onset. The patient underwent 30 treatments over 12 years after the first injection to improve upper and lower limb spasticity and abnormal gait patterns. The mean duration between injections was 147 days. Methods: The Modified Ashworth Scale, passive range of motion, gait velocity, and degree of abnormal gait patterns during treadmill gait were evaluated pre-injection and at 2, 6, and 12 weeks after every injection. Results: The follow-up period showed no injection-related adverse events. Comfortable overground gait velocity gradually improved over 30 injections. The Modified Ashworth Scale and passive range of motion improved after each injection. Pre-injection values of the degree of pes varus, circumduction, hip hiking, and knee extensor thrust improved gradually. However, the degree of contralateral vaulting, excessive lateral shift of the trunk, and insufficient knee flexion did not improve after 30 injections. Conclusion: Repeated botulinum toxin A injections effectively improve abnormal gait patterns, even when a single injection cannot change these values.

IJCM_232A: Identification of Kinematic Motifs in Crouch Gait of Children with Cerebral Palsy

Background: Crouch Gait is a fairly common pathological gait adaptation seen in children with Cerebral Palsy, characterized by inadequacy of plantar flexion, knee extension and hip extension in the stance phase of gait. From a kinetic perspective crouch gait severely impairs the ability to generate thrusting forces through the extensor muscles of stance extremity which is necessary for forward progression. Broader goal of this study was to develop and test a wearable robotic exoskeletal device for children with crouch gait, where a knee actuator provides extensor thrust. Artificial Intelligence (AI) models which control the torque output of the knee actuator, needed to be trained to activate, control, or organize the output. Objectives: Rhythmical/repetitive patterns, like the phases of normal gait, needed to be identified in crouch gait, which could be used to train AI models Methodology: A total of 30 children with cerebral palsy were screened of which 7 children aged between 7 and 14 years, who presented with classical crouch gait were recruited. Kinesiological data was collected through accelerometric and goniometric placed bilaterally on thigh, leg, and knee, as well as pressure sensors embedded on to bilateral insoles at the fore-foot and hind foot, while the children walked over a 5 meter course. All sensor data was relayed through an Arduino micro-controller unit for analog to digital conversion and stored on a laptop computer. All Accelerometer and goniometric data was plotted against time on MS Excel to identify specific patterns or motifs. Results: Key kinematic motifs could be identified in crouch gait, which bestowed semblance of rhythmicity, and cyclical pattern, which was difficult to identify under normal observation. Conclusion: Accelerometric, as well as goniometric data suggest the presence of inherent kinematic patterns in the same. These could be used for training AI models for robotic exoskeletal devices.

Effects of ankle-foot orthosis on gait pattern and spatiotemporal indices during treadmill walking in hemiparetic stroke.

Ankle-foot orthosis (AFO) is known to correct abnormal gait patterns and improve walking stability and speed in patients with hemiparesis. To quantify these benefits in post-stroke gait, a three-dimensional motion analysis of gait pattern was conducted. Forty patients with hemiparesis were enrolled. A three-dimensional motion analysis system was used to analyze patients' treadmill walking with/without an AFO. Outcome measures were 12 abnormal gait indices (forefoot contact, knee extensor thrust, retropulsion of the hip, flexed-knee gait, medial whip in the stance phase, circumduction gait, hip hiking, insufficient knee flexion during the swing phase, excessive lateral shifting of the trunk, contralateral vaulting, excessive hip external rotation, and posterior pelvic tilt), calculated using kinematic data and spatiotemporal indices, and the symmetry index of double-stance and single-stance time and step length. Forefoot contact (without AFO vs. with AFO: 71.0 vs. 65.8, P < 0.001), circumduction gait (65.0 vs. 57.9, P < 0.001), and contralateral vaulting (78.2 vs. 72.2, P = 0.003) were significantly reduced, whereas excessive hip external rotation (53.7 vs. 62.8, P = 0.003) significantly increased during walking with an AFO. Hip hiking (77.1 vs. 71.7) showed marginal reduction with the use of AFO ( P = 0.096). The absolute symmetry index of double-stance time (21.9 vs. 16.1, P = 0.014) significantly decreased during walking with an AFO. AFO effectively mitigates abnormal gait patterns typical of hemiparetic gait. A 3D motion analysis system with clinically oriented indices can help assess intervention efficacy for gait abnormalities.

Classification of abnormal gait patterns of poststroke hemiplegic patients in principal component analysis.

The objective of this study was to classify the 10 types of characteristic abnormal gait by principal component analysis using quantitative indices of 10 types of abnormal gait. For abnormal gait pattern classification, principal component analysis was performed using the deviation values of the 10 types of abnormal gait of 90 subjects. Scatter plots of the factor loadings of the 1st and 2nd principal components of the 10 types of abnormal gait were prepared, and those arranged at near sites were grouped based on the positional relationship, through which abnormal gait patterns were classified. It was suggested that abnormal gait patterns can be classified into insufficient knee flexion, hip hiking, and excessive lateral shift of the trunk over the unaffected side in the swing phase; knee extensor thrust pattern accompanying forefoot contact in the stance phase in addition to circumduction gait of the swing phase; and flexed knee gait pattern accompanying retropulsion of the hip in addition to median whip in the stance phase and excessive hip external rotation in the swing phase. It was clarified by these principal component analyses that information contained in the results of the 10 quantitative indices of abnormal gait of the 90 poststroke hemiplegia patients was compressed into several abnormal gait patterns. If observational abnormal gait analysis is performed after understanding this gait pattern classification, it may help improve the accuracy of gait analysis by observation.

Improving abnormal gait patterns by using a gait exercise assist robot (GEAR) in chronic stroke subjects: A randomized, controlled, pilot trial

BackgroundAlthough the Gait Exercise Assist Robot (GEAR) has been reported to effectively improve gait of hemiplegic patients, no study has investigated its use in chronic stroke patients. It is possible to facilitate gait reorganization by gait training with less compensation using the GEAR even in chronic stroke patients. Research questionWhat are the effects of GEAR training on the abnormal gait patterns of chronic stroke subjects? MethodsSubjects were randomly assigned to either the GEAR group (n = 8) or the treadmill group (n = 11). Each group underwent 20 sessions (40 min/day, 5 days/week). The changes in the 10 types of abnormal gait patterns were evaluated using a three-dimensional motion analysis system and the Global Rating of Change (GRC) scale before and after the intervention, and at 1-month and 3-month follow-up assessment. ResultsIn the GEAR group, hip hiking at a 1-month follow-up assessment was markedly lesser than that before the intervention, and the excessive hip external rotation at 3-month follow-up assessment was notably lesser than that after the intervention, but the change in excessive hip external rotation was in the normal range. In the treadmill group, knee extensor thrust at a 1-month follow-up assessment was strikingly lesser than that before the intervention, but the difference was in the normal range. In the GEAR group, the GRC scale scores were considerably higher after the intervention, at a 1-month, and 3-month follow-up assessment than those before the intervention. But, in the treadmill group, only the GRC scale score at a 1-month follow-up assessment was visibly higher than that before the intervention. SignificanceGait training using the GEAR may be more effective than treadmill-training in improving the swing phase in chronic stroke subjects.

Relationship between primitive reflex values and gross motor abilities in children with spastic cerebral palsy

Primitive reflexes are basically present in normal growth and these reflexes are background of gross motor development in the children. However, Cerebral palsy in the children had motor activity disruption. This study aims to determine the relationship between primitive reflex value and gross motor ability level in the children with spastic cerebral palsy. The study was used correlative research method with cross sectional design. The study population were children had spastic cerebral palsytipe who undergone therapy. The samples were 30 children who met the inclusion criteria such as children with spastic cerebral palsytipe who undergone therapy at Physiotherapy clinic, aged below than 8 years and willing to be respondents. The primitive reflex assessment used reflex value scale and gross motor skills is assessed based on Gross Motor Functional Classification System (GMFCS) level. The result found there was significant relationship between primitive reflexes and gross motor skills in 6 times of primitive reflexes such as ATNR (p=0.015), STNR (p=0.028), Moro (p=0.035), Neck righting (p=0.001), parachute (p=0.019) and foot placement reaction (p=0.015). Meanwhile, there was not significant relationship between extensor thrust and gross motor skills, p=0.164.

Effective Orthotherapy for an Extensor Thrust Pattern Worsening with the Recurrence of Cerebral Infarction: A Case Study

Effective Orthotherapy for an Extensor Thrust Pattern Worsening with the Recurrence of Cerebral Infarction: A Case Study

Quantitative assessment of knee extensor thrust, flexed-knee gait, insufficient knee flexion during the swing phase, and medial whip in hemiplegia using three-dimensional treadmill gait analysis

ABSTRACTBackground: Most people with hemiplegia experience gait changes after a stroke. Abnormal gait patterns in stroke patients vary across subjects and this make it difficult to assess the cause of gait abnormalities. Therefore, it is necessary to quantitatively evaluate abnormal gait patterns through gait analysis for stroke patients.Objective: To develop and evaluate the validity of quantitative assessments of the degree of knee extensor thrust, flexed-knee gait, insufficient knee flexion during the swing phase, and medial whip.Methods: Forty-six healthy control subjects and 112 people with hemiplegia participated. From the 112 patients, 50 patients were selected into each abnormal gait pattern (knee extensor thrust, flexed-knee gait, insufficient knee flexion during the swing phase, and medial whip) with some overlap. Participants were instructed to walk on a treadmill and were recorded using a three-dimensional motion analysis system. An index to quantify each of the four abnormal gait patterns exhibited by the patients was calculated from the three-dimensional coordinate data. The indices were developed based on the definition of the abnormal gait patterns. The index values for the patients were compared with those of healthy subjects as well as with the results of observational gait assessment by three physical therapists with expertise in gait analysis.Results: Strong correlation was observed between the index value and the median observational rating for all four abnormal gait patterns (−0.64 to −0.86). Most of the patients with an abnormal gait pattern had a higher index value than the healthy subjects.Conclusions: The use of these indices in gait analysis of people with hemiplegia can help to diagnose severity of gait disorder, determine the appropriate treatment, and evaluate the effectiveness of the treatment.

Developing a Dynamic Wheelchair Using the Design Structure Matrix Method

Involuntary extensor thrusts, experienced by wheelchair users with cerebral palsy, can cause injuries due to unexpected impacts with the wheelchair. Consequently, these unexpected motions can hurt the human body, damage the wheelchair, and change the correct position of the user’s pelvis. Many of the existing wheelchairs do not address all the needs of disabled people. The goal of this article is to develop an instrumented, dynamic seating system for people with extensor thrust using the Design Structure Matrix (DSM) tool in order to provide an efficient development sequence of the design tasks for three subsystems of the seat: the seat back, seat bottom, and footrest. This article provides a detailed application of the use of the DSM. It reveals that the design process of the three main systems can be executed concurrently with different teams having different specializations and proposes a method to minimize total design time.

3D-Quantitative evaluation of a rigid seating system and dynamic seating system using 3D movement analysis in individuals with dystonic tetraparesis

To improve postural stability in individuals with dystonic cerebral palsy, the concept of a dynamic seat has been suggested as a potential solution. An experimental set-up for the acquisition of movement during extensor thrusts while sitting on a seating system was defined and applied on a group of dystonic individuals, to compare a dynamic versus a rigid seat system, using quantitative movement analysis. The seating system in dynamic configuration is able to reduce the extensor thrust experienced by the consumers, as well as to increase range of motion in the anterior–posterior direction, limiting the sliding down of trunk and showing better upper limb smoothness during extensor thrusts. The procedures used in this study appear to provide a useful tool for better understanding how the concept of a dynamic back in a seat system may affect and influence position and stability of individuals with dystonia on the seat system.

Identification of human-generated forces on wheelchairs during total-body extensor thrusts

Involuntary extensor thrust experienced by wheelchair users with neurological disorders may cause injuries via impact with the wheelchair, lead to the occupant sliding out of the seat, and also damage the wheelchair. The concept of a dynamic seat, which allows movement of a seat with respect to the wheelchair frame, has been suggested as a potential solution to provide greater freedom and safety. Knowledge of the human-generated motion and forces during unconstrained extensor thrust events is of great importance in developing more comfortable and effective dynamic seats. The objective of this study was to develop a method to identify human-generated motions and forces during extensor thrust events. This information can be used to design the triggering system for a dynamic seat. An experimental system was developed to automatically track the motions of the wheelchair user using a video camera and also measure the forces at the footrest. An inverse dynamic approach was employed along with a three-link human body model and the experimental data to predict the human-generated forces. Two kinds of experiments were performed: the first experiment validated the proposed model and the second experiment showed the effects of the extensor thrust speed, the footrest angle, and the seatback angle. The proposed method was tested using a sensitivity analysis, from which a performance index was deduced to help indicate the robust region of the force identification. A system to determine human-generated motions and forces during unconstrained extensor thrusts was developed. Through experiments and simulations, the effectiveness and reliability of the developed system was established.

Neurological Evaluation of Toxic Axonopathies in Rats: Acrylamide and 2,5-Hexanedione

This research was conducted to determine which neurological test or combination of tests can provide sufficient functional information to compliment biochemical or morphological endpoints in mechanistic studies of toxic axonopathies. Using several neurological indices, we evaluated the effects of two prototypical neurotoxicants that cause distal axonopathy: acrylamide monomer (ACR) and 2,5-hexanedione (HD). For each toxicant, rats were exposed to two daily dosing rates (ACR, 50 mg/kg per day i.p. or 21 mg/kg per day, p.o.; HD, 175 or 400 mg/kg per day, p.o.) and neurological endpoints were determined two to three times per week. Specific tests included observations of spontaneous locomotion in an open field, and measurements of hindlimb landing foot splay, forelimb and hindlimb grip strength and the hindlimb extensor thrust response. For all neurological parameters, the magnitude of defect induced by either neurotoxicant was not related to daily dose-rate, e.g. both the lower and higher ACR dose-rates produced the same degree of neurological dysfunction. Instead, dose-rate determined onset and progression of neurotoxicity, e.g. the higher ACR dose-rate produced moderate neurotoxicity after approximately 8 days of intoxication, whereas the lower dose-rate caused moderate neurotoxicity after 26 days. Regardless of dose-rate, ACR-exposed rats exhibited gait abnormalities (ataxia, splayed hindlimbs), in conjunction with increased landing hindfoot spread and decreased hindlimb grip strength and extensor thrust. HD intoxicated rats exhibited hindlimb muscle weakness as indicated by a gait abnormality (dropped hocks) and decreases in grip strength and the extensor thrust response. However, hindlimb landing foot spread was not affected by HD exposure. For both neurotoxicants, gait changes preceded or coincided with alterations in other neurologic indices. These results suggest that observations of spontaneous behavior in an open field represent a practical approach to assessing temporal development and extent of neurological dysfunction induced by axonopathic toxicants such as ACR and HD.

Acupuncture in Neuromuscular Lesions of Animals

Acupuncture treatments are described in a dog with thoracic disc herniation, a cat with spinal injury, a dog with neurological disorders caused by cerebral contusion and two cross-bred calves with spastic paresis. The beneficial effects of acupuncture are reported: notably improvements in the extensor thrust, patella and coccygeal reflexes, balance, defaecation and micturition.

Quantification of the hindlimb extensor thrust response in rats.

This report describes a procedure for measuring the extensor thrust response (ETR) and summarizes the results of initial validation experiments using adult Long-Evans rats. The ETR can be quickly elicited and the force measured by pressing against the hindlimb footpads with a small rectangular plate or bar attached to a digital force gauge. Output of the force gauge is analyzed and displayed with commercially available hardware and software. The first experiment compared the acute effects of i.p. injection of chlorpromazine (CPZ; 1, 4, or 7 mg/kg) or amphetamine (AMP; 0.3, 1, or 3 mg/kg) on the ETR and forelimb/hindlimb grip strength (FL/HL-GS) in male and female rats. CPZ decreased both ETR and FL/HL-GS values. Both 1 and 3 mg/kg AMP increased grip strength values but decreased ETR values. A second experiment compared the evolution of changes in ETR, FL/HL-GS, and peripheral neurophysiological measures during 8 weeks of daily oral dosing of 10 mg/kg acrylamide (ACR) monomer. ACR-treated rats exhibited a progressive decrease in ETR beginning after 3 weeks of dosing, whereas a reduction of HL-GS was observed beginning much later, after 7 weeks of dosing. The deficit in ETR progressed in the absence of any changes in spontaneous or evoked electrophysiological abnormalities in neuromuscular function, but was accompanied by a decrease in peripheral nerve conduction velocity. Taken together, the results indicate that the ETR can be used to characterize functional effects in both single dose and repeated dose experiments. The data also indicate that the ETR does not merely duplicate the information provided by FL/HL-GS, and suggest a hypothesis that the ETR may be sensitive to neurotoxicant-induced changes in somatosensory function.

Muscle activity during forelimb reaching movements in rats

The absolute timing, and correlation in time of activity in a number of shoulder, elbow and wrist muscles in the rat was analysed in relation to onset and termination of the extension phase of a skilled forelimb reaching movement. Movement onsets were analysed separately in the component upward, forward and medial directions. On average, movements in the upward and medial directions occurred together, prior to forward movement. Latissimus dorsi activity was the earliest muscle event, occurring approximately 150 ms prior to movement, whilst onset of teres major activity, possibly related to paw elevation, had the highest temporal correlation with movement onset. Triceps activity was strongly time locked to the end of the reach, and may have provided final extensor thrust to complete the reaching movement. Although it is possible to speculate on possible roles of particular EMG bursts, multiple (often anatomically antagonistic) muscles were active at all stages of the reach, and no unique muscle relationships to initiation of individual movement components could be identified. It is concluded that reaching movements are produced by temporal variation in distributed activity among all available muscles.

Proximal hamstring lengthening in the sitting cerebral palsy patient.

We retrospectively studied 62 nonambulatory children with spastic quadriplegic cerebral palsy who underwent proximal hamstring lengthening to improve hip and spine positioning. Preoperatively, all had hamstring contracture, with difficulty sitting due to hip extensor thrust and increased kyphosis. Thirty-five patients with follow-up greater than or equal to 2 years were studied using a modified Reimer scale to assess sitting ability. Sitting ability improved significantly (p less than 0.01) postoperatively, along with popliteal angle (p less than 0.001) and straight leg raising (p less than 0.001). Proximal hamstring lengthening is effective in treating severe hamstring contractures in the wheelchair-bound child with cerebral palsy.

Functional recovery of locomotive behavior in the adult spinal dog.

Complete transection of the midthoracic spinal cord was performed on adult female dogs. Development of reflexes and locomotive movements in the hindlimbs after spinal transection was investigated over several months. In the earlier stages after the surgery, dogs showed flaccid paralysis of the hindlimbs. Within several weeks, muscle tone of the hindlimbs was gradually increased accompanied by development of flexion reflex with after-discharge in addition to monosynaptic reflexes. Alternating stepping movement also began to develop. Afterward, extensor thrust and crossed extension reflex were observed. Standing behavior of the hindlimbs was found after enough development of the extensor thrust and correct placement of the pads of the toes. Steady development of stepping and standing caused forward locomotion using fore- and hindlimbs. This walking behavior of the hindlimbs was never inhibited by additional spinal cord transection. These findings indicate that the isolated spinal cord caudal to the transected site is responsible for the locomotive behavior of the hindlimbs in adult spinal dogs. Spinal automatism and development of responses induced by afferent inflow from outside the cord may help to explain such functional recovery of the paralyzed hindlimbs.

Influence of Asphyxia on Reciprocal Innervation

In cats whose spinal cords had been asphyxiated for various periods of time, van Harreveld and Marmont found that after recovery the hind legs could show an exaggerated extensor tone which usually stayed until death (in some experiments 3 weeks in total). Considering that after this time the acute effect of asphyxia will have disappeared, it was concluded that the high extensor tone is caused by a more or less selective damage of an inhibiting system present in the cord which normally keeps the tone in check. A further study of these phenomena was made. A period of asphyxia for 30 minutes was usually followed within a few hours by the development of high extensor tone without abolishment of the flexor reflex. However, the effect of pinching the foot was not the same in all animals; sometimes it caused a regular flexor reflex with flexion in ankle and knee; in other experiments it caused, after the flexion, an extension of the leg, and in a few cases this stimulus caused instead of flexion an increase of the extensor tone. When the contractions of the M. tibialis anterior and the triceps group were recorded simultaneously, it was often seen that stimulation of the N. peroneus superficialis caused a contraction in both of these antagonists. In other animals it was observed that the stimulation of the sciatic nerve caused a contraction in the quadriceps muscle of a Sherrington preparation instead of inhibiting the tone in this muscle. By Sherrington's scheme for reciprocal innervation these observations can be best explained. Since, according to this scheme, the extensor motor neurones are inhibited during the flexor reflex, the simultaneous stimulation of afferent nerve fibers for extensor reflexes (e.g., for the extensor thrust) running in the stimulated branch of the sciatic nerve, normally remains without effect.

Dangerous Reflexes of Car Drivers

“How Cars go out of Control: an Analysis of the Driver's Reflexes” is the title of a paper by Dr. Yandell Henderson, professor of applied physiology in Yale University, read before the National Academy of Sciences, Washington, on November 18. He attributes this situation to the ‘self-righting’ reaction which is instinctively and irresistibly excited by any sudden severe disturbance of equilibrium. The self-righting reaction is proverbial in the cat: no matter how the cat is dropped, it lands always on its feet. Into this neuro-muscular complex in man enters the ‘extensor thrust’ reflex of the lower limbs, owing to which a motor-car driver, often quite unawaredly, presses the accelerator pedal hard down, and continues to do, thus sending the car completely ‘out of control’. Prof. Henderson realises that we cannot change the nature of so primitive a danger-response. His remedy consists in placing a pedal for the left foot “so low as scarcely to rise above the floor, but wide enough so that extension of the leg will always bring the foot to bear on it”. The extensor thrust reflex involves both feet. The left pedal will be so connected that heavy pressure on it will either counteract the action of the right foot and so close the throttle, or will directly shut down the carburetter. From statistical studies, Prof. Henderson believes that at least ten per cent of fatal car accidents are attributable to the car being ‘out of control’ through the ‘extensor thrust’ of the driver's legs.

SOME RESULTS OF SECTION OF PARTICULAR NERVE BRANCHES TO THE AMPULLÆ OF THE FOUR VERTICAL SEMICIRCULAR CANALS OF THE FROG

SOME RESULTS OF SECTION OF PARTICULAR NERVE BRANCHES TO THE AMPULLÆ OF THE FOUR VERTICAL SEMICIRCULAR CANALS OF THE FROG