Learning effects in human muscular responses to proprioceptive stimuli.
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Adult↗
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Results for “REFLEX, PROPRIOCEPTIVE”
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The postural reaction to the drop of a hindlimb support in the standing cat remains following sensorimotor cortical ablation.
The postural response to an unexpected drop of either hindlimb platform was studied in the freely standing cat. The vertical forces, the forelimb electromyographic (EMG) activities and the movement of the trunk were analysed. A stereotyped diagonal pattern of support was observed. The imposed unloading of one hindlimb was followed by unloading of the diagonally opposite forelimb and loading of the two other limbs. In the ipsilateral loaded forelimb, the force increase is preceded by an activation of the biceps and is concomitant with a triceps coactivation. In the contralateral unloaded forelimb, reciprocal changes of biceps (activation) and triceps (inhibition) were observed and preceded the force decrease. Lateral or vertical displacement or rotation of the vertebral column at the high thoracic level, as evidenced by movie recording, began no earlier than 100 ms after the hindlimb drop and thus followed the EMG changes. Unilateral sensorimotor cortex ablation had no effect on this pattern or on the latencies of forelimb myographic responses. These results suggest that the hindlimb drop triggers stereotyped forelimb EMG responses which are organized centrally and that these responses are not mediated via a sensorimotor cortical loop.
Animals↗
Forearm muscles of man can reverse their function after tendon transfers: an electromyographic study.
In patients suffering from paralysis of a major synergistic muscle group tendon transfers can be considered the therapy of choice in restoring the mobility of the affected joint(s). In order to study the mechanisms underlying the subsequent reversal of function in the transferred muscles, we have recorded the EMG of several forearm muscles in parallel and compared their activation periods with control data from healthy volunteers. Slow and fast extension-flexion movements of the wrist were evaluated. The findings demonstrated a 'new' phasic EMG activity within the transferred muscles, which correlated to their new mechanical function. However, the 'old' EMG pattern was not lost. In some muscles it was present in fast and slow wrist movements, in others only in fast ones. The results indicate that the reversal of function observed in the transferred muscles can be adjusted to meet the specific needs of the movement to be performed.
Adaptation, Physiological↗
Balance control in Sensory Neuron Disease.
OBJECTIVE: Balance control under static and dynamic conditions was assessed in patients with Sensory Neuron Disease (SND) in order to shed further light on the pathophysiology of ataxia. METHODS: Fourteen patients with diabetic polyneuropathy and 11 with SND underwent clinical and neurophysiological evaluation, stabilometric recording of body sway during quiet stance with and without vision, stereometric analysis of body segment displacement while riding a platform translating in anterior-posterior direction with and without vision (dynamic condition), and EMG recording of leg muscle responses to abrupt stance perturbation produced by rotation of a supporting platform. The findings were compared to those of age matched normal subjects. RESULTS: Clinical and neurophysiological evaluation revealed a more severe motor impairment in patients with diabetes than SND, while sensory impairment was superimposable. Some patients with SND had vestibular dysfunction of diverse severity. Body sway during stance was larger in patients with SND than diabetes with and without vision. In the stance perturbation condition, the latency of the long-loop EMG response to platform rotation was disproportionately increased with respect to the spinal response in the SND but not in diabetic patients. Under dynamic condition, patients with SND oscillated more than diabetic patients and several of them easily lost balance with eyes closed. CONCLUSIONS: Patients with SND show severe unsteadiness under both static and dynamic conditions, particularly with eyes closed. The patchy sensory loss of SND, disrupting sensation from territories other than the lower limbs and possibly including the vestibular nerve, could be responsible for this instability. Ataxia is correlated to the abnormal latency of the muscle responses to stance perturbation. Since increased response latencies cannot be attributed to a vestibular deficit, the deterioration of equilibrium control would be ascribed mainly to the degeneration of the central branch of the afferent fibres. SIGNIFICANCE: Measures of body balance under quiet stance and dynamic conditions can provide relevant diagnostic information as to the pathophysiology and severity of ataxia and viability of the central branch of the sensory fibres, and help in separating patients with peripheral neuropathy from patients with loss of sensory neurones.
Aged↗
Postural control in otolith disorders.
It was the aim of the present paper to investigate the influence of otolith disorders on human postural control by different methods. The 33 patients of our study had undergone a minor head injury and suffered subsequently from an utricular or sacculo-utricular disorder as evidenced by vestibular evoked myogenic potential recordings and eccentric rotation recordings of the otolith-ocular responses. Postural control was assessed by performing stance/gait tests (standard balance deficit test, SBDT) and by evaluating trunk sway (using angular velocity sensors). Moreover, classical tests of the posterior column of the spinal tract (Romberg/Unterberger) and the dynamic posturography (sensory organization test, SOT) were included. It could be shown that SBDT tasks with reduced proprioceptive and visual cues (e.g. standing on foam, eyes closed) are most sensitive for an otolith disorder. The patients showed an increased trunk sway in the pitch plane (i.e. linear motion as adequate utricular stimulus) and an increase in sway velocities (i.e. tilting movements as adequate saccular stimulus) compared to controls. The SOT was most sensitive for combined (sacculo-utricular) otolith disorders (78%) while vestibulospinal tests are not enough sensitive. In essence, otolith disorders evidently impair human postural control and have been possibly underestimated as a source of posttraumatic postural imbalance as yet.
Adult↗
Sensory-motor control of ligaments and associated neuromuscular disorders.
The ligaments were considered, over several centuries, as the major restraints of the joints, keeping the associated bones in position and preventing instability, e.g. their separation from each other and/or mal-alignment. This project, conducted over 25 years, presents the following hypothesis: 1. Ligaments are also major sensory organs, capable of monitoring relevant kinesthetic and proprioceptive data. 2. Excitatory and inhibitory reflex arcs from sensory organs within the ligaments recruit/de-recruit the musculature to participate in maintaining joint stability as needed by the movement type performed. 3. The synergy of the ligament and associated musculature allocates prominent role for muscles in maintaining joint stability. 4. The viscoelastic properties of ligaments and their classical responses to static and cyclic loads or movements such as creep, tension-relaxation, hysteresis and strain rate dependence decreases their effectiveness as joint restraint and stabilizers and as sensory organs and exposes the joint to injury. 5. Long-term exposure of ligaments to static or cyclic loads/movements in a certain dose-duration paradigms consisting of high loads, long loading duration, high number of load repetitions, high frequency or rate of loading and short rest periods develops acute inflammatory responses which require long rest periods to resolve. These inflammatory responses are associated with a temporary (acute) neuromuscular disorder and during such period high exposure to injury is present. 6. Continued exposure of an inflamed ligament to static or cyclic load may result in a chronic inflammation and the associated chronic neuromuscular disorder known as cumulative trauma disorder (CTD). 7. The knowledge gained from basic and applied research on the sensory - motor function of ligaments can be used as infrastructure for translational research; mostly for the development of "smart orthotic" systems for ligament deficient patients. Three such "smart orthosis", for the knee and lumbar spine are described. 8. The knowledge gained from the basic and applied research manifests in new physiotherapy modalities for ligament deficient patients. Ligaments, therefore, are important structures with significant impact on motor control and a strong influence on the quality of movement, safety/stability of the joint and potential disorders that impact the safety and health of workers and athletes.
Clinical Trials as Topic↗
Supplemental therapy in isolated vitamin E deficiency improves the peripheral neuropathy and prevents the progression of ataxia.
A 24-year-old male, who suffered since childhood from a progressive form of ataxia associated with peripheral neuropathy, was found severely deficient in serum vitamin E. He walked with bilateral aid and presented severe dysmetria of the limbs and dysarthric speech; muscular strength and trophism were slightly diminished in the distal muscles of four limbs and there was hypotonia of the arms; he presented absent deep tendon reflexes, bilateral Babinski's sign, reduced proprioception at four limbs, pes cavus and fasciculations of the tongue. Intestinal fat malabsorption and other gastrointestinal or haematological conditions associated with deficiency of this vitamin were ruled out. In this patient, after 2 years of a daily supplement of high doses of vitamin E, a further progression of the disease was not observed and, moreover, the neurophysiological characteristics of his neuropathy appeared clearly improved. A longitudinal evaluation of serum vitamin E levels showed values in the normal range after 13 months of therapy. The patient had molecular genetic analysis of chromosome 8 and was found homozygous for the unusual mutation 513insTT in the alpha-tocopherol transfer protein gene.
Administration, Oral↗
A new surgery for congenital nystagmus: effects of tenotomy on an achiasmatic canine and the role of extraocular proprioception.
PURPOSE: Human eye-movement recordings have documented that surgical treatment of congenital nystagmus (CN) also produces a broadening of the null zone and changes in foveation that allow increased acuity. We used the achiasmatic Belgian sheepdog, a spontaneously occurring animal model of human CN and see-saw nystagmus (SSN), to test the hypothesis that changes induced by surgical interruption of the extraocular muscle afference without a change in muscle-length tension could damp both oscillations. METHODS: An achiasmatic dog with CN and SSN underwent videotaping and infrared oculography in a sling apparatus and head restraints before and after all extraocular muscles (stage 1: 4 horizontal rectus muscles and stage 2 [4 months later]: 4 vertical rectus muscles and 4 oblique muscles) were surgically tenotomized and immediately reattached at their original insertions. RESULTS: The dog had immediate and persistent visible, behavioral, and oculographic changes after each stage of this new procedure. These included damped CN and SSN, increased ability to maintain fixation, and increased periods of maintaining the target image on the area centralis over a broad range of gaze angles. CONCLUSIONS: Severing and reattaching the tendons of the extraocular muscles affect some as-yet-unknown combination of central nervous system processes producing the above results. This new procedure may prove effective in patients with CN with either no null, a null at primary position, or a time-varying null (due to asymmetric, (a)periodic, alternating nystagmus). We infer from our results in an achiasmatic dog that tenotomy is the probable cause of the damping documented in human CN after Anderson-Kestenbaum procedures and should also damp CN and SSN in achiasma in humans. It may also prove useful in acquired nystagmus to reduce oscillopsia. The success of tenotomy in damping nystagmus in this animal suggests that the proprioceptive feedback loop has a more important role in ocular-motor control than has been appreciated. Finally, we propose a modified bimedial recession procedure, on the basis of the damping effects of tenotomy.
Animals↗
Progressive ataxia due to central demyelination in Rottweiler dogs.
A clinicopathological study of a neurologic disease in Rottweiler dogs was conducted. Clinical data were available on 16 dogs, 11 of which were examined pathologically. All dogs had a history of progressive gait abnormalities, which had commenced insidiously at an age varying from 1.5 to 3.5 years. In most dogs the fore limbs were affected prior to the hind limbs. At neurologic examination ataxia of all 4 limbs was seen, in some instances accompanied by an apparent paresis. Proprioceptive positioning was delayed whereas spinal reflexes were often hyperactive. Plain and contrast radiographs of the spine did not reveal any compressive lesions in 5 dogs examined. Cerebrospinal fluid analysis in 4 dogs was normal. Electrodiagnostic testing in 3 dogs revealed no abnormalities. At pathologic examination demyelinating lesions were found in the central nervous system. These were largely confined to the cervical spinal cord and brain stem and had a rather characteristic more or less symmetric distribution. Pedigree data suggested that the disease is transmitted genetically.
Animals↗
Head movements during locomotion in a gibbon and Japanese macaques.
Kinematic analysis of head and body movements during locomotion in Macaca fuscata and Hylobates lar revealed that coordinated head rotation and translation that have been reported to play an important role in stabilizing gaze during locomotion for humans are also observed in non-human primates. The fact that well-coordinated head movements were observed in two species, and during both bipedal and quadrupedal walking, suggests that the head orientation during locomotion is well regulated in the manner of top-down control over the species and modes of locomotion. The result validates the monkey model and enables us to explore the underlying mechanisms for gaze, head, and postural control during locomotion.
Animals↗
Cervical and thoracic vertebral malformation ("weak neck") in Colombia lambs.
The purpose of this study is to describe a developmental defect of the caudal cervical and cranial thoracic vertebrae in 11 purebred Colombia lambs. The lambs were either affected at birth, or developed the condition within the first 18 days of age. Cervicothoracic kyphosis, with a compensatory cervical lordosis and ataxia were common; 8 lambs had abnormal head posture, characterized by inability to lift the head from the ground. One lamb had rigid head and neck, and had to move the entire body to look to the left or right. Neurological signs included ataxia, tetraparesis, diminished conscious proprioception, and increased patellar and triceps reflexes. One lamb had inspiratory stridor because of compression of the trachea in the area overlying the abnormal vertebrae (cervical vertebrae 6 [C6] and 7 [C7]). Radiographic and pathological abnormalities included malalignment and malarticulation of the caudal cervical and cranial thoracic spine, rounded cranioventral margins in the bodies of vertebrae C7 and T1, wedging of the intervertebral disc spaces between C6 and T1 vertebrae, and hypoplasia of the dens. Pathological changes in the soft tissues included hypoplasia of the cervical epaxial and hypaxial musculature, with associated focal areas of myodegeneration. Mild Wallerian axonal degeneration, compatible with a mild cord compression syndrome, was found in 3 lambs in the cervicothoracic spinal cord adjacent to the vertebral anomalies. The concentrations of copper and selenium in blood, plasma, or tissues were normal in 10 of 11 lambs. All but one of the lambs in which pedigree information was provided were genetically related. Siblings born as twins to 5 of the affected lambs were normal, but both lambs from one twin pregnancy were affected. Owners reported that breeding stock had been shared among the ranches. Because of the close familial relationships of the affected lambs, the condition is suspected to have a hereditary basis.
Animals↗
Underlying mechanisms of the effects of spinal cord stimulation in motor disorders. A review of the discussion.
Possible underlying neurophysiological mechanisms of spinal cord stimulation in the modification of motor disorders were discussed by scientists working in research on motor control mechanisms. Changes of motor unit properties in upper motoneuron lesions were reviewed, the role of proprioceptive input and long-loop reflexes in motor control was discussed, analysis of ramp and ballistic movements in motor control was presented, and some aspects of neural control of locomotion were reviewed. Some physiological considerations of the influence of electrical stimulation on various neural functions were given and the conclusion was reached that, at present, no definitive models of the action of spinal cord stimulation are available.
Animals↗
Investigation of a family with hypertrophic neuropathy resembling Roussy-Levy syndrome. Clinical, electrophysiologic, histologic, and biochemical studies.
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Adolescent↗
The contribution of proprioception to posture control in normal subjects.
In order to investigate the contribution of proprioceptive input to maintaining an upright position, stabilometry via 100-Hz vibratory stimulation applied to the Achilles tendon was studied and analyzed with respect to area, length and power spectra according to the method of fast Fourier transform (FFT). Twenty-one young medical students were analyzed in this study. When vibration was applied, the body sway was significantly greater than that of control in area and length with both eyes open and closed. There was a significant increase of total power in both the lateral (X) and antero-posterior (Y) directions with the eyes closed. With the eyes open, an increase was found only in the antero-posterior direction. The frequency band indicating the maximum spectrum did not shift. Significant increases in power spectra were found in the frequency range of more than 2 Hz in both two directions with the eyes closed. It was concluded that a vibration given to the Achilles tendon provoked a pronounced high frequency body sway especially in the antero-posterior direction when visual information was nullified, and that proprioceptive information may have a minor role compared with visual information.
Achilles Tendon↗
Differential control of leg and trunk muscle activity by vestibulo-spinal and proprioceptive signals during human balance corrections.
Knowledge about how proprioceptive signals trigger and modulate human balance corrections has important implications for the rehabilitation of postural and gait disorders, and increases our understanding of normal interactions between these sensory systems. We used combinations of support-surface rotation and rearward translation to examine the triggering effects of ankle and knee movements on balance corrections. By comparing the responses in normal subjects to those in persons with a bilateral peripheral vestibular deficit, we determined the modulating influence of vestibular inputs on balance responses. Differences in normal and vestibular-loss responses under the different proprioceptive conditions revealed four general findings. First, ventral leg muscle responses are strongly modulated by vestibulo-spinal inputs and by proprioceptive inputs from the ankle and knee. Second, triceps surae muscle responses are initially dependent on ankle inputs, and after 100 ms are modulated by knee inputs; they are not altered by vestibular loss. Third, paraspinal responses in vestibular-loss subjects are enhanced because of unstable trunk sway induced by the lack of ventral leg-muscle activity. Fourth, the earliest possible triggering signal for establishing the timing of interlink muscle activity appears to be knee flexion and/or trunk rotation on the pelvis. These results indicate that a confluence of knee and trunk proprioceptive and vestibulo-spinal inputs, rather than either input alone, is involved in establishing the muscle synergy underlying normal balance corrections.
Electromyography↗
Recent advances in cerebellar physiology and pathology.
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Animals↗
[Spinal anesthesia with bupivacaine for a patient with a history of severe leg pain after intrathecal dibucaine].
An 87-year-old man was scheduled for the 11th transurethral bladder tumor resection (TURBT). He had a history of non-active syphilis for 21 years, diabetes mellitus for 7 years, and severe emphysema. Preoperative physical examination of the lower extremities, revealed loss of knee-jerk reflex, and loss of vibratory and proprioceptive perception. Four years previously, he underwent TURBT twice under spinal anesthesia with dibucaine, which caused severe leg pain during anesthesia. Therefore, subsequent TURBTs (eight times) were performed under general anesthesia with tracheal intubation, which frequently caused postoperative respiratory distress. Recently, bupivacaine, less neurotoxic than dibucaine, was on the market in Japan for use in spinal anesthesia. Therefore we planned spinal anesthesia using 0.5% bupivacaine, 2.0 ml. This time, he did not complain of leg pain during anesthesia, and postoperative conditions were satisfactory. We can conclude that bupivacaine is very useful for spinal anesthesia especially in patients with a history of leg pain by spinal anesthesia with dibucaine.
Aged↗
[Cortical control of movements and its regulation by proprioceptive afferences].
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Afferent Pathways↗