PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “REFLEX, PROPRIOCEPTIVE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2006

Improvements in performance following optometric vision therapy in a child with dyspraxia.

SS, an 8-year-old boy with dyspraxia, presented for behavioural optometry assessment. He had been diagnosed with a subtle form of dyspraxia by his paediatric occupational therapist, based on poor proprioception, delayed bilateral integration and poor visual perception. A full visual assessment was carried out. SS was given a programme of reflex inhibition exercises for 3 months. Then, a programme of optometric vision therapy (OVT) exercises was prescribed at home and in practice for a period of 8 months. SS was assessed using a battery of occupational therapy Sensory Integration and Praxis Tests (SIPT) before optometric intervention, and after OVT. There were significant improvements in fusional reserves, accommodative facility and oculomotor control of pursuit and saccadic eye movements. His reading level had changed by 4 years in 11 months. The SIPT results showed improvements in the visual and motor/visual perception subtests, confirming the significant changes in visual perceptual performance. Consideration is given to treatment modalities for dyspraxia, and the studies confirming their effectivity of approach. This case study provides evidence supporting the use of OVT eye exercises in dyspraxia, ocular motility, accommodative dysfunction, learning difficulties and sports performance. The need for further research and inter-professional working is discussed.

Apraxias↗
PubMed1995

Idiopathic distal small fiber neuropathy.

We describe the clinical details of 20 elderly patients with idiopathic small fiber neuropathy. This neuropathy is ubiquitous in practice but has not been well characterized. The clinical syndrome is relatively stereotyped and appears to be a frequent cause of burning feet in the elderly. The main features were burning, painful paresthesias and dysesthesias in the feet, lancinating pains, moderate to severe distal small fiber sensory loss, absent ankle reflexes, and minimal or no distal foot weakness. All but 2 had mild loss of vibration sense but none had significant proprioceptive loss or sensory ataxia. EMG was normal in 9 while the others had a mild sensorimotor axonal neuropathy. Sural nerve biopsy was normal in 3 and showed axonal loss in 6. Progression was slow, and although pain was a troublesome symptom, no patient became disabled. Symptoms were refractory to most symptomatic therapies but several patients improved with gammaglobulin infusions.

Adult↗
PubMed1984

Arousal response induced by postural changes in patients with subacute myelo-optico-neuropathy, "SMON".

In reaction time (RT) experiments, shifts of arousal level induced by postural changes were examined in 10 normal subjects and 10 patients with SMON. Vocal RTs were recorded at neutral position (N) and facilitating position of the left arm (FA) or the left leg (FL). RT-ratios between two positions, FA/N and FL/N, were used as variables to estimate the arousing effect of facilitating positions. Also the correlations between these variables and several clinical signs such as patellar tendon reflex (PTR), sensory disturbance and dysesthesia were calculated. The grade of dysesthesia was strongly related to FL/N. It is assumed that proprioceptive input from the lower extremities causes abnormally high arousal response in patients with dysesthesia.

Adult↗
PubMed1980

Epileptogenic stimulation of the cortical masticatory area and the mesencephalic trigeminal nucleus.

1. The effects of epileptogenic stimulation of the cerebral masticatory area on the somata of the first-order neurons of masticatory proprioception localized in the mesencephalic trigeminal nucleus (MTN) were studied in curarized, lightly anaesthetized rabbits. 2. Low-frequency stimulations inducing modest cortical after-discharges fired the silent MTN units with latencies of 0.3-0.8 sec, and induced alternate excitatory and inhibitory effects on the active units. On some occasions the tonic afferent discharge was changed into rhythmic bursts, which occurred at the constant frequency of 2.5-3.5/sec for the entire range of stimulation frequencies used, i.e. from 0.3 to 10/sec. 3. High-frequency cortical stimulations eliciting true epileptic seizures induced a transient increase in discharge of the MTN units, followed by a prolonged inhibition. 4. All these effects were attributed to activation of reticular pathways acting on the some of the recorded proprioceptive neurons. Such a modulation of the proprioceptive input elicited by the epileptic masticatory cortex may contribute to the motor effects and to the changes of the masseteric reflex which occur during convulsive seizures.

Animals↗
PubMed1983

Proprioceptive control of a muscle receptor organ in the locust leg.

In the locust hind leg a muscle receptor organ (MRO) consisting of a single multipolar sensory neuron and a receptor muscle spans the joint between coxa and trochanter. Several other proprioceptors of the same joint exert reflexes onto the single excitatory motoneuron specific to the receptor muscle. The resulting changes in muscular tension in turn strongly affect afferent discharge of the MRO.

Animals↗
PubMed2002

Eye position signals modify vestibulo- and cervico-ocular fast phases during passive yaw rotations in humans.

We studied the amplitude, latency, and probability of occurrence of fast phases (FP) in darkness to unpredictable vestibular and/or cervical yaw stimulation in normal human subjects. The rotational stimuli were smoothed trapezoidal motion transients of 14 degrees amplitude and 1.25 s duration. Eye position before stimulus application (initial eye position, IEP) was introduced as a variable by asking the subjects to fixate a spot appearing either straight ahead or at 7 degrees eccentric positions. The recordings demonstrated that the generation of FP during vestibular stimulation was facilitated when the whole-body rotation was directed opposite the eccentric IEP. Conversely, FP were attenuated if the whole-body rotation was directed toward the eccentric IEP; i.e., the FP attenuated if they were made to further eccentric positions. Cervical stimulation-induced FP were small and variable in direction when IEP was directed straight ahead before stimulus onset. Eccentric IEPs resulted in large FP, the direction of which was essentially independent of the neck-proprioceptive stimulus. They tended to move the eye toward the primary position, both when the trunk motion under the stationary head was directed toward or away from the IEP. FP dependence on IEP was evident also during head-on-trunk rotations. No consistent interaction between vestibularly and cervically induced FP was found. We conclude that extraretinal eye position signals are able to modify vestibularly evoked reflexive FP in darkness, aiming at minimizing excursions of the eyes away from the primary position. However, neck-induced FP do not relate to specific tasks of stabilization or visual search. By keeping the eyes near the primary position, FP may permit flexibility of orienting responses to incoming stimuli. This recentering bias for both vestibularly and cervically generated FP may represent a visuomotor optimizing strategy.

Adult↗
PubMed1979

Effect of haloperidol on reflex activation of rat alpha-motoneurones. A possible explanation for akinesia and catalepsy?

Effects of haloperidol on rat flexor and extensor alpha-motoneurones were studied in ventral roots of laminectomized rats under halothane anesthesia. The alpha-motoneurones were activated by tetanic stimulation of low-threshold afferents (group I and II), either of the ipsilateral peroneal nerve ("flexor alpha-motoneurones") or gastrocnemius-soleus nerve ("extensor alpha-motoneurones"). Haloperidol, given in the doses of 0.075, 0.15 and 0.30 mg/kg i.p. inhibited the reflex activation of flexor alpha-motoneurones; higher doses seemed to be more effective than lower ones. Apomorphine (2 mg/kg s.c.) partially antagonized the inhibitory action of haloperidol with some latency. Higher doses of haloperidol (0.15-0.60 mg/kg i.p.) also inhibited the reflex activation of extensor alpha-motoneurones; this inhibitory effect was, at least for a short time, antagonized by apomorphine (2 mg/kg s.c.). The threshold for reflex activation both of flexor and extensor alpha-motoneurones was raised by haloperidol and lowered by a subsequent administration of apomorphine. Our results suggest that akinesia and catalepsy, induced in rats by haloperidol might be, at least in part, due to a decrease in sensitivity of alpha-motoneurones to proprioceptive stimuli.

Animals↗
PubMed1976

Modifications and development of spinal reflexes in the alert baboon (Papio papio) following an unilateral vestibular neurotomy.

Unilateral vestibular neurotomy performed on 6 baboons was followed by the classical postural and locomotor postoperative disorders. Postoperative spinal reflex excitability was studied in these awake baboons by measuring monosynaptic recruitment ratios in soleus motoneuronal pool and the recovery cycle of the monosynaptic response. Vestibular neurotomy induces: (1) asymmetrical spinal reflexes with a decrease of the recruitment on the side of the section and an increase on the opposite side. (2) a modification of phases IV and V of the ipsilateral recovery cycle. The recovery during postoperative days of normal recruitment curves and recovery cycles is described. This recovery is relatively fast and relates closely to the compensation of postural and locomotor disorders. We note the importance of an early active motor exploration on the time-course of recovery: postoperative disorders in posture and locomotion are reduced much later when baboons are submitted to a motor restriction. These findings suggest a combined alpha and gamma-hypoexcitability of the ipsilateral hindlimb. The study of the recovery process suggests that the cerebellum is involved in the compensatory mechanisms. The regression of postural disorders, observed both in restrained and unrestrained baboons, demonstrates the importance of central regulations using proprioceptive afferents for recovery.

Animals↗
PubMedDate not supplied

The effects of joint position and direction of joint motion on proprioceptive sensibility in anterior cruciate ligament-deficient athletes.

We studied a group of anterior cruciate ligament-deficient athletes to identify whether joint position and direction of joint motion have a significant effect on proprioception. Twenty-nine anterior cruciate ligament-deficient athletes were tested for their threshold to detect passive motion at both 15 degrees and 45 degrees moving into the directions of both flexion and extension. The single-legged hop test was used to identify function in the deficient limb. Results demonstrated statistically significant deficits in threshold to detect passive motion for the deficient limb at 15 degrees moving into extension. For the deficient limb, threshold to detect passive motion was significantly more sensitive moving into extension than flexion at a starting angle of 15 degrees; at a starting angle of 15 degrees moving into extension threshold was significantly more sensitive than at a starting angle of 45 degrees moving into extension. We conclude that in deficient limbs proprioception is significantly more sensitive in the end ranges of knee extension (15 degrees) and is significantly more sensitive moving into the direction of extension. To effectively restore reflex stabilization of the lower limb we recommend a rehabilitation program emphasizing performance-based, weightbearing, closed kinetic chain exercise for the muscle groups that act on the knee joint.

Adolescent↗
PubMed2006

In humans Ib facilitation depends on locomotion while suppression of Ib inhibition requires loading.

The role of force feedback during gait is still a matter of debate. From work on cats, it is known that input from Golgi tendon organs from triceps surae does produce Ib facilitation during locomotion instead of autogenic inhibition. In humans, Stephens and Yang (Stephens, M.J., Yang, J.F., 1996. Short latency, non-reciprocal group I inhibition is reduced during the stance phase of walking in humans. Brain Res. 743, 24-31) found that voluntary contraction results in a reduction of Ib inhibition. During gait, they even observed Ib facilitation in a subset of subjects. This raises the question whether the crucial elements involved in these changes are either loading of the leg or locomotion. To examine this question, Ib reflexes were investigated during sitting, lying supine, lying supine with 300 N pressure applied to the foot sole, standing, and a rhythmic loading and unloading task called "reduced" gait. Ib inhibition was obtained during sitting and lying supine. This inhibition was significantly reduced or disappeared during standing and when lying supine but loaded. During the stance phase of "reduced" gait, the inhibition disappeared in eight subjects, and even a facilitation was observed in six subjects. It is concluded that the decrease in Ib inhibition from gastrocnemius to soleus occurs during a load-bearing condition and does not require locomotion. In contrast, Ib facilitation requires locomotion at least in a rudimentary form.

Electromyography↗
PubMed1996

Effects of differently induced stretch loads on neuromuscular control in drop jump exercise.

The neuromuscular characteristics of the triceps surae and vastus lateralis muscles and interactions between the pre-activation of these muscles and the muscle output itself during ground contact were investigated during various types of stretch-shortening cycle muscle loading. The loading of the muscles was effected by using three different types of drop jump exercise. These jumps allowed separate modifications of the loading of the leg extensor muscles by changing the velocity of the centre of gravity (CG) or by changing directly the body mass, which was also affected by changing artificially the acceleration of the CG. It was found that the eccentric peak angular velocity of the ankle joint was related to the various precontact and eccentric parameters in all the different types of jumping exercise. The correlations were higher for the gastrocnemius muscle (P < 0.001) than for the soleus muscle (n.s., P < 0.01). In all the experimental conditions, the pre-activation of the measured muscles started well before the impact of contact with the ground. However, the duration of the pre-activation phase depended on the type of stretch exercise. The results would suggest a clear interaction between the pre-activation of the muscles and that part of the muscle output which is effected by the segmental stretch reflex system. The control mechanism of the pre-activation itself appears to be multiple in character. It seems reasonable to assume that the pre-activation is preprogrammed, but which can, however, be modified by proprioceptive, vestibular and visual inputs. Thus, the possibility of conscious modification of the expected muscle load must be considered.

Adult↗
PubMed1981

Proprioceptive input from the jaw muscles and its influence on lapping, chewing, and posture.

Experiments are described which define criteria for identifying fusimotor axons discharging in filaments of the masseter nerve in lightly anaesthetized cats. During reflex movements of the jaw two patterns of discharge were observed in different fusimotor fibres. One type, called "sustained," fired at a fairly constant increased rate. The other, called "modulated," fired at high frequencies during the extrafusal muscle contraction. Evidence from spindle primary and secondary recordings in similar experiments strongly suggests that the "sustained" type were dynamic fusimotor fibres and the "modulated" type were static fusimotor fibres. New spindle recordings in normal unanaesthetized cats indicate that the modulated pattern of static fusimotor discharge also occurs in these conditions. Its effect is to reduce the tendency for spindle afferents to become silent during muscle shortening. A proposal is made that the static fusimotor discharge in cyclic movements may represent a temporal "template" for the intended movement as directed by the central pattern generator.

Animals↗