scholarly journals Contributions of Altered Stretch Reflex Coordination to Arm Impairments Following Stroke

2010 ◽  
Vol 104 (6) ◽  
pp. 3612-3624 ◽  
Author(s):  
Randy D. Trumbower ◽  
Vengateswaran J. Ravichandran ◽  
Matthew A. Krutky ◽  
Eric J. Perreault
Keyword(s):  
Stretch Reflex ◽  
Muscle Activation ◽  
Motor Impairment ◽  
Load Condition ◽  
Elbow Flexion ◽  
Control Group ◽  
Stretch Reflexes ◽  
Reflex Pathways ◽  
Stroke Group ◽  
Arm Function

Patterns of stereotyped muscle coactivation, clinically referred to as synergies, emerge following stroke and impair arm function. Although researchers have focused on cortical contributions, there is growing evidence that altered stretch reflex pathways may also contribute to impairment. However, most previous reflex studies have focused on passive, single-joint movements without regard to their coordination during volitional actions. The purpose of this study was to examine the effects of stroke on coordinated activity of stretch reflexes elicited in multiple arm muscles following multijoint perturbations. We hypothesized that cortical injury results in increased stretch reflexes of muscles characteristic of the abnormal flexor synergy during active arm conditions. To test this hypothesis, we used a robot to apply position perturbations to impaired arms of 10 stroke survivors and dominant arms of 8 healthy age-matched controls. Corresponding reflexes were assessed during volitional contractions simulating different levels of gravitational support, as well as during voluntary flexion and extension of the elbow and shoulder. Reflexes were quantified by average rectified surface electromyogram, recorded from eight muscles spanning the elbow and shoulder. Reflex coordination was quantified using an independent components analysis. We found stretch reflexes elicited in the stroke group were significantly less sensitive to changes in background muscle activation compared with those in the control group ( P < 0.05). We also observed significantly increased reflex coupling between elbow flexor and shoulder abductor–extensor muscles in stroke subjects relative to that in control subjects. This increased coupling was present only during volitional tasks that required elbow flexion ( P < 0.001), shoulder extension ( P < 0.01), and gravity opposition ( P < 0.01), but not during the “no load” condition. During volitional contractions, reflex amplitudes scaled with the level of impairment, as assessed by Fugl-Meyer scores ( r2 = 0.63; P < 0.05). We conclude that altered reflex coordination is indicative of motor impairment level and may contribute to impaired arm function following stroke.

Measuring poststroke spasticity

2000 ◽  
Vol 10 (1) ◽  
pp. 69-74 ◽  
Author(s):  
J. M. Gregson ◽  
A. K. Sharma
Keyword(s):  
Normal State ◽  
Stretch Reflex ◽  
Muscle Activation ◽  
Muscle Tone ◽  
Clinical Syndrome ◽  
Motor Disorder ◽  
Muscle Forces ◽  
Joint Movement ◽  
Stretch Reflexes ◽  
Reflex Action

What is spasticity?Spasticity is a well-recognized and potentially important clinical syndrome comprising inappropriate and involuntary high muscle tone. It has been variably defined, with debate still ongoing. Currently, the most widely accepted definition is that of Lance, stating that spasticity is ‘a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyper-excitability of the stretch reflex.’ Unfortunately, even this description does not fully encompass the multifactorial nature of spasticity, since resistance to movement, even in the normal state, is subject to varied contributors. These include patient volition, inertia, visco-elastic muscle forces and range of joint movement, as well as true muscle activation secondary to reflex action. In the real clinical world, it is often not possible to distinguish which of these features is/are dominant. Furthermore, spastic muscle undergoes physiopathological, rheologic change with stiffness, atrophy, fibrosis and finally contracture.

scholarly journals Visually-updated hand state estimates modulate the proprioceptive reflex independently of motor task requirements

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Sho Ito ◽  
Hiroaki Gomi
Keyword(s):  
Stretch Reflex ◽  
Muscle Activation ◽  
Motor Task ◽  
Proprioceptive Information ◽  
Motor Tasks ◽  
Stretch Reflexes ◽  
Motor Mapping ◽  
Task Requirements ◽  
Multimodal Information ◽  
Proprioceptive Reflex

Fast signaling from vision and proprioception to muscle activation plays essential roles in quickly correcting movement. Though many studies have demonstrated modulation of the quick sensorimotor responses as depending on context in each modality, the contribution of multimodal information has not been established. Here, we examined whether state estimates contributing to stretch reflexes are represented solely by proprioceptive information or by multimodal information. Unlike previous studies, we newly found a significant stretch-reflex attenuation by the distortion and elimination of visual-feedback without any change in motor tasks. Furthermore, the stretch-reflex amplitude reduced with increasing elimination durations which would degrade state estimates. By contrast, even though a distortion was introduced in the target-motor-mapping, the stretch reflex was not simultaneously attenuated with visuomotor reflex. Our results therefore indicate that the observed stretch-reflex attenuation is specifically ascribed to uncertainty increase in estimating hand states, suggesting multimodal contributions to the generation of stretch reflexes.

scholarly journals Altered activation patterns by triceps surae stretch reflex pathways in acute and chronic spinal cord injury

2011 ◽  
Vol 106 (4) ◽  
pp. 1669-1678 ◽  
Author(s):  
Alain Frigon ◽  
Michael D. Johnson ◽  
C. J. Heckman
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Stretch Reflex ◽  
Triceps Surae ◽  
Stretch Reflexes ◽  
Activation Patterns ◽  
Intact State ◽  
Hindlimb Muscles ◽  
Reflex Pathways ◽  
Cord Injury

Spinal reflexes are modified by spinal cord injury (SCI) due the loss of excitatory inputs from supraspinal structures and changes within the spinal cord. The stretch reflex is one of the simplest pathways of the central nervous system and was used presently to evaluate how inputs from primary and secondary muscle spindles interact with spinal circuits before and after spinal transection (i.e., spinalization) in 12 adult decerebrate cats. Seven cats were spinalized and allowed to recover for 1 mo (i.e., chronic spinal state), whereas 5 cats were evaluated before (i.e., intact state) and after acute spinalization (i.e., acute spinal state). Stretch reflexes were evoked by stretching the left triceps surae (TS) muscles. The force evoked by TS muscles was recorded along with the activity of several hindlimb muscles. Stretch reflexes were abolished in the acute spinal state due to an inability to activate TS muscles, such as soleus (Sol) and lateral gastrocnemius (LG). In chronic spinal cats, reflex force had partly recovered but Sol and LG activity remained considerably depressed, despite the fact that injecting clonidine could recruit these muscles during locomotor-like activity. In contrast, other muscles not recruited in the intact state, most notably semitendinosus and sartorius, were strongly activated by stretching TS muscles in chronic spinal cats. Therefore, stretch reflex pathways from TS muscles to multiple hindlimb muscles undergo functional reorganization following spinalization, both acute and chronic. Altered activation patterns by stretch reflex pathways could explain some sensorimotor deficits observed during locomotion and postural corrections after SCI.

scholarly journals Stroke Leads to Abnormal Coordination of the Multiple Upper Extremity Joints During Passive Movement

2020 ◽  
Author(s):  
Kyung Koh ◽  
Dongwon Kim ◽  
Giovanni Oppizzi ◽  
Chunyang Zhang ◽  
Glenn Kehs ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Motor Impairment ◽  
Arm Movement ◽  
Passive Movement ◽  
The Body ◽  
Uncontrolled Manifold ◽  
Control Group ◽  
Joint Torques ◽  
Stroke Group ◽  
Coordination Patterns

Abstract Background Motor impairments in the upper extremity (UE) is one of the most common deficits after stroke. Even though understanding of UE coordination deficits in persons with strokes is critical for better identification of motor impairment and planning for rehabilitation, it is still not clear how stroke affects coordination patterns of multi-joint movements in the UE. Here, we investigated kinematic and kinetic coordination patterns of UE after stroke during controlled passive arm movement. Methods An exoskeleton multi-joint robot moved the participant’s arm in the horizontal plane back and forth in 8 repetitions, in inward movement (i.e. toward the body) and outward movement (i.e. away from the body). The uncontrolled manifold analysis (UCM) was used to quantify kinematic and kinetic coordination patterns of the UE. Variability of joint angles and torques were decomposed into task-relevant variability (TRV) and task-irrelevant variability (TIV). An index of coordination (IC) was defined based on TRV and TIV. Results We found that the IC of joint torques in the stroke group significantly decreased during outward movement in comparison to that during inward movement, while IC of the control group showed no difference between the two movement directions. The decreased IC in the stroke group during outward movement was mainly due to the increased TRV of joint torques. In the further analysis of individual joint level, during outward movement, stroke group had a greater TRV of joint torques at all joints while during inward movement, stroke group had a lower TRV of joint torques at elbow joint. Conclusions Our results indicate that the stroke can cause the kinetic coordination deficits induced during a passive movement especially in outward movement. Our findings suggest that it is important to consider the passive kinetic coordination deficits to enhance post-stroke rehabilitation interventions. Trial registration clinicaltrials.gov, ID: NCT02359812. Registered 23 January 2015; Last Updated 06 August 2020.

scholarly journals Clinical Outcome and Histological Findings After Induced Leakage of PMMA Loaded With Methotrexate and Cisplatin During Vertebroplasty: Experimental Model in Pigs

2021 ◽  
pp. 219256822199480
Author(s):  
Alvaro Silva González ◽  
Rafael Llombart-Blanco ◽  
Marcela Gallegos Angulo ◽  
Carlos Villas Tomé ◽  
Matías Alfonso Olmos-García
Keyword(s):  
Spinal Cord ◽  
Experimental Model ◽  
Motor Impairment ◽  
Clinical Results ◽  
Control Group ◽  
Safe Procedure ◽  
Group 4 ◽  
Cement Leak ◽  
Group 2 ◽  
Histological Results

Study Design: Animal experimental model. Objective: To study the clinical behavior and histological changes in the spinal cord, nerve roots and perivertebral muscles of the spine after induced leakage of polymethylmethacrylate (PMMA) loaded with antiblastic drugs during vertebroplasty in an animal model of pigs. Methods: We performed vertebroplasty on 25 pigs. The animals were divided into 3 groups: vertebroplasty with PMMA alone (control group), vertebroplasty with PMMA loaded with methotrexate (MTX) and vertebroplasty with PMMA loaded with cisplatin (CYS). At 2 vertebral levels, epidural and prevertebral, massive cement leaks were induced. Animals were evaluated daily. Two weeks later, the pigs were sacrificed, and the tissues that came in contact with the cement were analyzed. Results: The clinical results for each of the groups were reported. The control group had no clinical alterations. In the MTX group, 2 pigs died before 1 week due to pneumonitis. In the CYS group, 4 animals had motor impairment, and 3 of the 4 had paraplegia. The histological results were as follows: the control and MTX groups showed synovial metaplasia, inflammatory reaction, crystal deposits, and giant cell reaction in the dura mater and muscle and all the animals in the CYS group had spinal cord and muscular necrosis. Conclusions: Massive cement leak after vertebroplasty with PMMA loaded with cisplatin is extremely toxic to the spinal cord and muscles around the spine. Therefore, its use cannot be recommended for the treatment of vertebral metastases. Using PMMA loaded with methotrexate seems to be a safe procedure, but further research is needed.

scholarly journals The Effects of Abdominal Hypopressive Training on Postural Control and Deep Trunk Muscle Activation: A Randomized Controlled Trial

2021 ◽  
Vol 18 (5) ◽  
pp. 2741
Author(s):  
María del Mar Moreno-Muñoz ◽  
Fidel Hita-Contreras ◽  
María Dolores Estudillo-Martínez ◽  
Agustín Aibar-Almazán ◽  
Yolanda Castellote-Caballero ◽  
...  
Keyword(s):  
Postural Control ◽  
Muscle Activation ◽  
Center Of Pressure ◽  
Controlled Trial ◽  
Trunk Muscle ◽  
Posture Control ◽  
Trunk Muscles ◽  
Control Group ◽  
Female Population ◽  
Imaging Results

Background: Abdominal Hypopressive Training (AHT) provides postural improvement, and enhances deep trunk muscle activation. However, until recently, there was a lack of scientific literature supporting these statements. The major purpose of this study was to investigate the effect of AHT on posture control and deep trunk muscle function. Methods: 125 female participants aged 18–60 were randomly allocated to the Experimental Group (EG), consisting of two sessions of 30 min per week for 8 weeks of AHT, or the Control Group (CG), who did not receive any treatment. Postural control was measured with a stabilometric platform to assess the static balance and the activation of deep trunk muscles (specifically the Transverse Abdominal muscle (TrA)), which was measured by real-time ultrasound imaging. Results: The groups were homogeneous at baseline. Statistical differences were identified between both groups after intervention in the Surface of the Center of Pressure (CoP) Open-Eyes (S-OE) (p = 0.001, Cohen’s d = 0.60) and the Velocity of CoP under both conditions; Open-Eyes (V-OE) (p = 0.001, Cohen´s d = 0.63) and Close-Eyes (V-CE) (p = 0.016, Cohen´s d = 0.016), with the EG achieving substantial improvements. Likewise, there were statistically significant differences between measurements over time for the EG on S-OE (p < 0.001, Cohen´s d = 0.99); V-OE (p = 0.038, Cohen´s d = 0.27); V-CE (p = 0.006, Cohen´s d = 0.39), anteroposterior movements of CoP with Open-Eyes (RMSY-OE) (p = 0.038, Cohen´s d = 0.60) and activity of TrA under contraction conditions (p < 0.001, Cohen´s d = 0.53). Conclusions: The application of eight weeks of AHT leads to positive outcomes in posture control, as well as an improvement in the deep trunk muscle contraction in the female population.

Incomplete Muscle Activation After Training With Electromyostimulation

1998 ◽  
Vol 23 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Tibor Hortobágyi ◽  
Jean Lambert ◽  
Kevin Scott
Keyword(s):  
Key Words ◽  
Muscle Activation ◽  
Motor Units ◽  
Eccentric Contraction ◽  
Key Words Exercise ◽  
Eccentric Contractions ◽  
Control Group ◽  
Force Ratio ◽  
Evoked Force ◽  
Large Motor

Training with voluntary or electromyostimulation (EMS)-evoked eccentric contractions should produce complete muscle activation, since EMS and eccentric contractions preferentially recruit large motor units. Subjects (22 women ages 18-40) were randomly assigned to a voluntary (VOL; n = 8), EMS (n = 8), or control group. VOL and EMS groups trained the quadriceps at the same, increasing force levels 4 times/week for 6 weeks using voluntary or EMS-evoked eccentric contractions. VOL improved voluntary more than EMS-evoked eccentric strength. EMS improved EMS-evoked strength more than voluntary. EMS training improved EMS-evoked eccentric strength more than VOL training improved voluntary eccentric strength. EMS-evoked to voluntary force ratio increased from 0.57 (±0.11) to 1.20 (±0.35) in EMS and did not change in VOL (all changes p < .05). Six of eight EMS subjects produced greater EMS-evoked force posttraining, suggesting incomplete muscle activation after EMS training. Key words: exercise, eccentric contraction, muscle activation

Statistical Considerations When Assessing Short Latency Stretch Reflexes in the Human Soleus Muscle

Motor Control ◽  
2015 ◽  
Vol 19 (4) ◽  
pp. 253-270 ◽  
Author(s):  
Asger Roer Pedersen ◽  
Peter William Stubbs ◽  
Jørgen Feldbæk Nielsen
Keyword(s):  
Ankle Joint ◽  
Soleus Muscle ◽  
Stretch Reflex ◽  
Short Latency ◽  
Response Magnitude ◽  
Variance Heterogeneity ◽  
Stretch Reflexes ◽  
Response Characteristics ◽  
Normally Distributed

The aim was to investigate trial-by-trial response characteristics in the short-latency stretch reflex (SSR). Fourteen dorsiflexion stretches were applied to the ankle joint with a precontracted soleus muscle on 2 days. The magnitude and variability of trial-by-trial responses of the SSR were assessed. The SSR was log-normally distributed and variance heterogeneous between subjects. For some subjects, the magnitude and variance differed between days and stretches. As velocity increased, variance heterogeneity tended to decrease and response magnitude increased. The current study demonstrates the need to assess trial-by-trial response characteristics and not averaged curves. Moreover, it provides an analysis of SSR characteristics accounting for log-normally distributed and variance heterogeneous trial-by-trial responses.

scholarly journals The surface electromyography analysis of the non-plegic upper limb of hemiplegic subjects

2010 ◽  
Vol 68 (4) ◽  
pp. 562-566 ◽  
Author(s):  
Heloyse U Kuriki ◽  
Raquel N. de Azevedo ◽  
Augusto C. de Carvalho ◽  
Fábio Mícolis de Azevedo ◽  
Rúben F Negrão-Filho ◽  
...  
Keyword(s):  
Control Group ◽  
Electromyographic Activity ◽  
Healthy Individuals ◽  
Wrist Flexion ◽  
Functional Changes ◽  
Normal Individuals ◽  
Flexor Muscles ◽  
Stroke Group ◽  
Dominant Member ◽  
Flexion And Extension

Many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. This study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. The flexor muscles activation of stroke group (average 464.6 u.n) was significantly higher than the same muscles in control group (mean: 106.3 u.n.) during the wrist flexion, what shows that the non affected side does not present activation in the standart of normality found in the control group.

scholarly journals Sequential muscle activation in the hemiparetic arm

2004 ◽  
Vol 60 (2) ◽  
Author(s):  
C. Mucha
Keyword(s):  
Patient Group ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Deltoid Muscle ◽  
Middle Part ◽  
Control Group ◽  
Biceps Muscle ◽  
Significant Prolongation ◽  
Healthy Control ◽  
Simultaneous Activation

This study investigated the chronological activation sequence of multiple joint movements of the hemiparetic arm in patients with central hemiparesis compared to healthy test subjects.Twelve patients with central hemiparesis and eight healthy control subjects were studied. First, in rapid abduction movement of the upper limb, the electromyographic activities of the middle part of the deltoid muscle, the brachial biceps muscle and the extensor muscles of the fingers, were registered. Second, in rapid flexion of the arm, the electromyographic activities of the ventral part of the deltoid muscle, the brachial biceps muscle and the superficial flexor muscles of the fingers, were measured. From the EMG data registered, activation duration, activation latency and the innervation sequence were determined and compared between the patient group and the control group. In the patient group, a significant prolongation of the activation duration was shown only in abduction. However, the activation latency was significantly prolonged in both movements compared to healthy test subjects. In the innervation sequences, a simultaneous activation was most frequently shown in healthy subjects. In healthy subjects, the deltoid muscle also usually functioned as leading muscle, whereas there was sometimes a shift distally to the brachial biceps muscle in the hemiparetic patients. The speed of rapid multiple joint movements in hemiparetic extremities seems to be unaffected in certain movements (anteversion), in others (abduction) it seems to be significantly reduced. This, as well as the fact that the activation latency is significantly longer in the hemiparetic limbs should be taken into consideration when choosing rehabilitation exercises.

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