Modulation of Soleus H-Reflexes During Gait in Children With Cerebral Palsy

2007 ◽  
Vol 98 (6) ◽  
pp. 3263-3268 ◽  
Author(s):  
Maike Hodapp ◽  
Cornelia Klisch ◽  
Volker Mall ◽  
Julia Vry ◽  
Wiltrud Berger ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Stance Phase ◽  
Corticospinal Tract ◽  
Progressive Increase ◽  
Healthy Children ◽  
Step Cycle ◽  
Cerebral Lesions ◽  
Age Dependent ◽  
Modulation Pattern ◽  
Tonic Reflex

In healthy adults, soleus H-reflexes are rhythmically modulated and generally depressed during gait compared with rest. From ages 6 to 13 yr, there is a progressive increase in the tonic inhibition of H-reflexes during walking, especially during the stance phase of the step cycle. In adults, rhythmic modulation and tonic depression are severely disturbed after bilateral spinal lesions but remain partly preserved after unilateral cerebral lesions. Children with diplegic cerebral palsy (CP) suffer from a bilateral supraspinal lesion of the corticospinal tract that occurs before the maturation of the CNS is complete. If supraspinal structures are involved in the tonic, but not rhythmic, age-dependent reflex depression, it could be hypothesized that the tonic reflex depression with age is disturbed in CP, whereas the rhythmic part of the modulation remains unaffected. To test this hypothesis, soleus H-reflexes were assessed during gait in 16 CP children aged 5–11 and 15–16 and compared with 25 age-matched healthy children walking at similar velocities. Although the rhythmic part of the modulation pattern was present in CP, there was no significant tonic reflex depression with age, thus reflecting a lack of maturation of the corticospinal tract. It is argued the rhythmic part of the modulation may be generated on a spinal or brain stem level and is therefore not affected by the bilateral supraspinal lesion, whereas the tonic depression that occurs with maturation of the CNS is under supraspinal control. In conclusion, the supraspinal structures affected in CP are therefore likely involved in this age-dependent tonic depression.

scholarly journals Studies on the Corticospinal Control of Human Walking. I. Responses to Focal Transcranial Magnetic Stimulation of the Motor Cortex

1999 ◽  
Vol 81 (1) ◽  
pp. 129-139 ◽  
Author(s):  
Charles Capaday ◽  
Brigitte A. Lavoie ◽  
Hugues Barbeau ◽  
Cyril Schneider ◽  
Mireille Bonnard
Keyword(s):  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Stance Phase ◽  
Corticospinal Tract ◽  
Human Walking ◽  
Step Cycle ◽  
Motor Circuits ◽  
Significant Difference ◽  
Stimulation Of

Capaday, Charles, Brigitte A. Lavoie, Hugues Barbeau, Cyril Schneider, and Mireille Bonnard. Studies on the corticospinal control of human walking. I. Responses to focal transcranial magnetic stimulation of the motor cortex. J. Neurophysiol. 81: 129–139, 1999. Experiments were done to determine the extent to which the corticospinal tract is linked with the segmental motor circuits controlling ankle flexors and extensors during human walking compared with voluntary motor tasks requiring attention to the level of motor activity. The motor cortex was activated transcranially using a focal magnetic stimulation coil. For each subject, the entire input-output (I-O) curve [i.e., the integral of the motor evoked-potential (MEP) versus stimulus strength] was measured during a prescribed tonic voluntary contraction of either the tibialis anterior (TA) or the soleus. Similarly, I-O curves were measured in the early part of the swing phase, or in the early part of the stance phase of walking. The I-O data points were fitted by the Boltzmann sigmoidal function, which accounted for ≥80% of total data variance. There was no statistically significant difference between the I-O curves of the TA measured during voluntary ankle dorsiflexion or during the swing phase of walking, at matched levels of background electromyographic (EMG) activity. Additionally, there was no significant difference in the relation between the coefficient of variation and the amplitude of the MEPs measured in each task, respectively. In comparison, during the stance phase of walking the soleus MEPs were reduced on average by 26% compared with their size during voluntary ankle plantarflexion. Furthermore, during stance the MEPs in the inactive TA were enhanced relative to their size during voluntary ankle plantarflexion and in four of six subjects the TA MEPs were larger than those of the soleus. Finally, stimulation of the motor cortex at various phases of the step cycle did not reset the cycle. The time of the next step occurred at the expected moment, as determined from the phase-resetting curve. One interpretation of this result is that the motor cortex may not be part of the central neural system involved in timing the motor bursts during the step cycle. We suggest that during walking the corticospinal tract is more closely linked with the segmental motor circuits controlling the flexor, TA, than it is with those controlling the extensor, soleus. However, during voluntary tasks requiring attention to the level of motor activity, it is equally linked with the segmental motor circuits of ankle flexors or extensors.

scholarly journals Gait biometrics in children with cerebral palsy before and after robotic mechanotherapy

2020 ◽  
Vol 8 (2) ◽  
pp. 159-168
Author(s):  
Igor E. Nikityuk ◽  
Galina A. Ikoeva ◽  
Elizaveta L. Kononova ◽  
Irina Yu. Solokhina
Keyword(s):  
Cerebral Palsy ◽  
Motor Activity ◽  
Lower Extremities ◽  
Diagnostic Methods ◽  
Locomotor Training ◽  
Healthy Children ◽  
Step Cycle ◽  
Software Complex ◽  
Children With Cerebral Palsy ◽  
Before And After

Background. The improvement in existing methods and the development of new principles for treating children with cerebral palsy necessitates a quantitative assessment of the parameters of motor activity. However, because of the explicit and complex abnormalities in motor skills in patients with severe forms of cerebral palsy, an evaluation of their locomotor function dynamics using instrumental diagnostic methods remains a serious problem. Aim. This work aimed to study the walking function in patients with cerebral palsy before and after motor rehabilitation using a biomechanical method with biometric sensors. Materials and methods. We examined 14 patients with cerebral palsy aged 8 to 13 years with III level of restriction of motor activity according to the gross motor function classification system (GMFCS). All patients underwent rehabilitation in the Lokomat robotic simulator for three weeks. The course consisted of 15 sessions of 45 min each. The temporal and dynamic parameters of walking were studied in 14 patients with cerebral palsy before and after a course of locomotor training. The biometry of the step cycle was studied using the STEDIS hardware-software complex, including the Neurosens set of wireless biometric sensors. The temporal characteristics of the step cycle and the force interaction of the lower extremities with the supporting surface during walking were recorded. For comparison, we conducted a biomechanical examination of 18 healthy children of the same age who did not have signs of orthopedic disorders. Results. Although after a course of mechanotherapy, the indices of the support phases in biometry in children with cerebral palsy did not reach the level of healthy individuals, a physiological tendency to roll foot was observed in the phase of pushing and accelerating the foot. Active braking of the lower limb increased. The studied time parameters showed a relative improvement in the step structure because of the emerging tendency to normalize the ratio of the periods of the double support of the contralateral lower extremities. Conclusion. Robotic mechanotherapy helps to change the biomechanical pattern of walking of a child with a severe degree of cerebral palsy. An instrumental analysis of walking using wireless biometric sensors allows you to evaluate the results and effectiveness of rehabilitation measures in patients with severe motor impairment objectively.

scholarly journals Effects of Tendon Release Surgery on Inter-Limb Leg Stiffness Control in Children with Spastic Diplegic Cerebral Palsy during Gait

2021 ◽  
Vol 11 (10) ◽  
pp. 4562
Author(s):  
Chien-Chung Kuo ◽  
Hsing-Po Huang ◽  
Hsuan-Yu Lu ◽  
Tsan-Yang Chen ◽  
Ting-Ming Wang ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Stance Phase ◽  
Reaction Force ◽  
Bilateral Symmetry ◽  
Healthy Controls ◽  
Leg Stiffness ◽  
Characteristic Features ◽  
Total Leg ◽  
Analysis System ◽  
Single Limb Support

Impaired motor control and musculotendon tightness in the lower extremities are characteristic features of patients with diplegic cerebral palsy (CP). Tendon release surgery (TRS) helps improve joint and leg stiffness, but the effects of TRS on inter-limb coordination in terms of the total leg stiffness, and the bilateral symmetry in leg stiffness during gait, remain unknown. Ten children with spastic diplegic CP scheduled for TRS and ten healthy controls participated in this study. The inter-limb sharing of total leg stiffness during double-limb support phase and bilateral leg stiffness symmetry during stance phase of gait were calculated using the kinematic and ground reaction force data measured by a motion analysis system. Before TRS, the patients with diplegic CP walked with a decreased share of total leg stiffness during weight-acceptance (p < 0.05) and with increased bilateral leg stiffness asymmetry during single-limb support and weight-transfer during gait (p < 0.05) when compared to healthy controls. After TRS, the bilateral leg stiffness asymmetry was significantly reduced in the CP group, especially in the terminal stance phase, with inter-limb sharing of total leg stiffness becoming similar to that in controls (p > 0.05). The surgery seemed to improve the lower limb control and increased the bilateral limb symmetry during gait.

Evaluating upper body movements during gait in healthy children and children with diplegic cerebral palsy

2007 ◽  
Vol 16 (3) ◽  
pp. 175-180 ◽  
Author(s):  
Jacqueline Romkes ◽  
Wietske Peeters ◽  
Aidia M. Oosterom ◽  
Sara Molenaar ◽  
Iris Bakels ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Upper Body ◽  
Healthy Children ◽  
Body Movements

The Exoskeleton and Insect Proprioception: III. Activity of Tribal Campaniform Sensilla During Walking in the American Cockroach, Periplaneta Americana

1981 ◽  
Vol 94 (1) ◽  
pp. 57-75
Author(s):  
SASHA N. ZILL ◽  
DAVID T. MORAN
Keyword(s):  
Stance Phase ◽  
Periplaneta Americana ◽  
Specific Activity ◽  
Firing Frequency ◽  
American Cockroach ◽  
Campaniform Sensilla ◽  
Afferent Activity ◽  
Step Cycle ◽  
Slow Walking ◽  
Oriented Parallel

1. In the cockroach tibia, the activities of campaniform sensilla that monitor cuticular strain have been recorded in free-walking animals. 2. In walking, sensillum firing is correlated with myographic activity of the flexor and extensor tibiae muscles. 3. The specific activity of a single campaniform sensillum depends upon the orientation of its cuticular cap. 4. In slow walking, proximal sensilla, whose ovoid cuticular caps are oriented perpendicular to the leg long axis, fire in bursts that are initiated just prior to the onset of extensor tibiae activity in the stance phase of locomotion. The firing frequency within bursts of proximal sensilla is generally inversely related to the frequency of the slow extensor tibiae motoneurone and ceases when motoneurone activity exceeds 200 Hz. 5. Distal campaniform sensilla, oriented parallel to the leg long axis, only fire when slow extensor tibiae activity exceeds 300 Hz. In slow walking, distal sensillum activity typically occurs as a short intense burst near the end of the stance phase of the step cycle, when slow extensor frequency is maximal. Distal sensillum firing is greatly increased when forward progression is impeded. 6. The patterns of afferent activity seen in slow walking indicate that the campaniform sensilla function in load compensation and limitation of muscle tensions. The proximal sensilla respond to initial loading of the leg and can reflexly excite the slow extensor motoneurone in compensation. The distal sensilla respond to cuticular strains that result from large extensor contractions and can reflexly inhibit the slow motoneurone. 7. In rapid walking, activities of both subgroups of campaniform sensilla shift in phase relative to slow extensor firing. Proximal sensilla activity occurs after the onset of slow extensor firing. Distal sensilla bursts follow the termination of slow extensor activity. 8. These phase shifts limit the reflex functions of the tibial campaniform sensilla in rapid walking. Shifts in phase of afferent activity may contribute to the need for central programming of locomotion.

Corrective responses to loss of ground support during walking. I. Intact cats

1994 ◽  
Vol 71 (2) ◽  
pp. 603-610 ◽  
Author(s):  
M. A. Gorassini ◽  
A. Prochazka ◽  
G. W. Hiebert ◽  
M. J. Gauthier
Keyword(s):  
Stance Phase ◽  
Afferent Input ◽  
Emg Activity ◽  
Step Cycle ◽  
Trap Door ◽  
Ground Support ◽  
Extensor Muscles ◽  
Activation Profile ◽  
Corrective Response ◽  
Hindlimb Kinematics

1. In the cat step cycle the electromyographic (EMG) activity in ankle extensor muscles commences approximately 70 ms before foot contact. There is a sharp peak between 10 and 25 ms after contact and the EMG then declines for the remainder of the stance phase. It has been posited that the abrupt transition in EMG after contact is the consequence of reflexes elicited by the large barrage of afferent input that signals foot touchdown. However, it is also possible that the basic profile might be generated within the CNS, with little modification by afferent input. 2. These ideas were tested in 11 normal cats. We compared EMG responses and hindlimb kinematics in steps with normal ground support and steps in which an actuator-controlled trap door unexpectedly opened, withdrawing ground support just before foot contact. 3. In the absence of ground support the transition in EMG activity was still present. The averaged EMG pattern was similar for at least 30 ms after the foot passed through the plane of the floor. We conclude that the basic extensor activation profile in this part of the cycle is generated centrally and is not substantially altered by afferent input. 4. Between 35 and 200 ms after contact the stance phase was aborted and the foot was lifted smartly out of the hole. This reaction varied both in latency and kinematic detail, suggesting a fairly complex corrective response.(ABSTRACT TRUNCATED AT 250 WORDS)

Contribution of hind limb flexor muscle afferents to the timing of phase transitions in the cat step cycle

1996 ◽  
Vol 75 (3) ◽  
pp. 1126-1137 ◽  
Author(s):  
G. W. Hiebert ◽  
P. J. Whelan ◽  
A. Prochazka ◽  
K. G. Pearson
Keyword(s):  
Electrical Stimulation ◽  
Stance Phase ◽  
Flexor Muscle ◽  
Step Cycle ◽  
Locomotor Rhythm ◽  
Ia Afferents ◽  
Group I ◽  
Flexor Muscles ◽  
Group Ii ◽  
Stimulation Of

1. In this investigation, we tested the hypothesis that muscle spindle afferents signaling the length of hind-leg flexor muscles are involved in terminating extensor activity and initiating flexion during walking. The hip flexor muscle iliopsoas (IP) and the ankle flexors tibialis anterior (TA) and extensor digitorum longus (EDL) were stretched or vibrated at various phases of the step cycle in spontaneously walking decerebrate cats. Changes in electromyogram amplitude, duration, and timing were then examined. The effects of electrically stimulating group I and II afferents in the nerves to TA and EDL also were examined. 2. Stretch of the individual flexor muscles (IP, TA, or EDL) during the stance phase reduced the duration of extensor activity and promoted the onset of flexor burst activity. The contralateral step cycle also was affected by the stretch, the duration of flexor activity being shortened and extensor activity occurring earlier. Therefore, stretch of the flexor muscles during the stance phase reset the locomotor rhythm to flexion ipsilaterally and extension contralaterally. 3. Results of electrically stimulating the afferents from the TA and EDL muscles suggested that different groups of afferents were responsible for the resetting of the step cycle. Stimulation of the TA nerve reset the locomotor step cycle when the stimulus intensity was in the group II range (2-5 xT). By contrast, stimulation of the EDL nerve generated strong resetting of the step cycle in the range of 1.2-1.4 xT, where primarily the group Ia afferents from the muscle spindles would be activated. 4. Vibration of IP or EDL during stance reduced the duration of the extensor activity by similar amounts to that produced by muscle stretch or by electrical stimulation of EDL at group Ia strengths. This suggests that the group Ia afferents from IP and EDL are capable of resetting the locomotor pattern generator. Vibration of TA did not affect the locomotor rhythm. 5. Stretch of IP or electrical stimulation of TA afferents (5 xT) during the flexion phase did not change the duration of the flexor activity. Stimulation of the EDL nerve at 1.8-5 xT during flexion increased the duration of the flexor activity. In none of our preparations did we observe resetting to extension when the flexor afferents were activated during flexion. 6. We conclude that as the flexor muscles lengthen during the stance phase of gait, their spindle afferents (group Ia afferents for EDL and IP, group II afferents for TA) act to inhibit the spinal center generating extensor activity thus facilitating the initiation of swing.

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