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PubMed2006

[Electromyographic study of stretch reflexes in the normal and prosthetic hip].

PURPOSE OF THE STUDY: Several studies have been devoted to the effect of proprioception on joint function. Modifications in feedback control from the cord have been observed in unstable joints due to capsule and ligament laxity. A few studies have examined the effect of knee and hip arthroplasty on proprioception, but none have established whether stretch reflexes affect function of a prosthetic joint. The purpose of the present study was to demonstrate the electromyographic characteristics of stretch reflexes of the normal hip joint and to compare them with those observed in the prosthetic hip. MATERIAL AND METHODS: Two groups of patients were studied. The first included eleven subjects free of neurological disorders whose studied limb was healthy. The second group included ten subjects with a total hip prosthesis who had undergone extensive capsulectomy during the arthroplasty. Voluntary muscle contraction was noted in each subject. In addition, electromyographic recordings were made to note response of the ipsilateral and contralateral quadriceps crural and tensor of the fascia lata during changes in joint position. Recordings were made with the subject in the supine position, the limb suspended, hip flexed at 45 degrees and knee extended. Three series of ten recordings were made in random order to measure the latency of muscle response to free fall of the limb, accelerated fall of the relaxed limb, and accelerated fall associated with calibrated contraction of the quadriceps. Mean latency of muscle response was calculated for each trial. RESULTS: In the conditions of this study, there was no statistically significant difference (p = 0.05) in the reflex time course between natural and prosthetic hips. DISCUSSION: Changes due to joint replacement and capsulectomy do not appear to affect the stretch reflexes of the hip joint.

Aged↗
PubMed1981

Proprioception and exodeviations.

When a slight adductive force is applied by forceps to the straight or master eye in exotropia, the exodeviated or slave eye assumes the straight position. The nature of this phenomenon was studied. The reflex occurred in an all-or-none form and showed little dose response, that is, the slave eye did not adduct beyond the straight position even if an extreme forced adduction was applied to the master eye. Once the slave eye assumed the straight position by the reflex it maintained this position, even when the master eye was covered, except when the master eye was released from the forced adduction. This reflex movement response occurred promptly on repeated forced adduction at 9 Hz on the master eye, while the visual movement of the eye was limited to follow 1 Hz movement of the target. The reflex occurred readily in the light but hardly at all in the dark. From these facts the authors conclude that the reflex is brought about as a result of interaction between the proprioceptive impulse and the visual input, where the former may chiefly constitute the signal, while the latter restricts the threshold of the reflex pathway.

Electrooculography↗
PubMed2006

Hip-phase-dependent flexion reflex modulation and expression of spasms in patients with spinal cord injury.

The flexion reflex in human spinal cord injury (SCI) is believed to incorporate interneuronal circuits that consist elements of the stepping generator while ample evidence suggest that hip proprioceptive input is a controlling signal of locomotor output. In this study, we examined the expression of the non-nociceptive flexion reflex in response to imposed sinusoidal passive movements of the ipsilateral hip in human SCI. The flexion reflex was elicited by low-intensity stimulation (300 Hz, 30 ms pulse train) of the right sural nerve at the lateral malleolus, and recorded from the tibialis anterior (TA) muscle. Sinusoidal hip movements were imposed to the right hip joint at 0.2 Hz by a Biodex system while subjects were supine. The effects of leg movement on five leg muscles along with hip, knee, and ankle joint torques were established simultaneously with the modulation pattern of the flexion reflex during hip oscillations. Phase-dependent modulation of the flexion reflex was present during hip movement, with the reflex to be significantly facilitated during hip extension and suppressed during hip flexion. The phase-dependent flexion reflex modulation coincided with no changes in TA pre- and post-stimulus background ongoing activity during hip extension and flexion. Reflexive muscle and joint torque responses, induced by the hip movement and substantiated by excitation of flexion reflex afferents, were entrained to specific phases of hip movement. Joint torque responses were consistent with multi-joint spasmodic muscle activity, which was present mostly during the transition phase of the hip from flexion to extension and from mid- to peak extension. Our findings provide further evidence on the interaction of hip proprioceptors with spinal interneuronal circuits engaged in locomotor pathways, and such interaction should be considered in rehabilitation protocols employed to restore sensorimotor function in people with SCI.

Adult↗
PubMed1983

[Electromyographic study of 50 cases of Werdnig-Hoffmann disease].

An electromyographic study was performed in 50 cases of severe infantile spinal muscular atrophy (type I). 164 muscles and 93 nerves (ulnar and posterior tibialis) were tested. The thresholds of stimulation of the motor nerves were increased. Motor action potential was absent in 30% of the investigated nerves, motor nerve conduction velocity was slow in 44%, H reflex was absent in 86%. Proprioceptive nerve conduction velocity was slow in some cases. Using the long-time (50-100 msec) direct longitudinal technique of muscle stimulation (provoked fibrillation), denervation could be proved in 98% of cases. The authors emphasize diagnostical difficulties in the first days of life.

Electromyography↗
PubMed1991

Contribution of eye muscle proprioception to velocity-response characteristics of eye movements: involvement of the cerebellar flocculus.

The vestibulo-ocular reflex (VOR) and optokinetic nystagmus (OKN) were examined in alert pigmented rabbits following interruption of proprioceptive afferents from the extraocular muscles in one eye by surgical section of the ophthalmic branch of the trigeminal nerve (V1 nerve). Deficits were mainly produced in movement dynamics of the ipsilateral eye including reduction of (1) the VOR gain at a high frequency of head rotation, (2) the OKN gain and (3) the velocity of quick eye movements in the OKN. In some of the rabbits examined, the cerebellar flocculus was lesioned by local injection of kainic acid before severance of the V1 nerve. No significant additional reductions of VOR or OKN gains were produced by V1 nerve section in the flocculus-lesioned rabbits. These results suggest that proprioceptive signals from eye muscles act to improve VOR and OKN dynamics through the neuronal mechanisms involving the cerebellar flocculus.

Animals↗
PubMed2005

Reflex regulation of antagonist muscles for control of joint equilibrium position.

A systems model of spinal neuro-musculo-skeletal system (alpha - gamma model) is developed to investigate the plausible roles of spinal proprioceptive feedback in movement control. The model is composed of a joint, a pair of antagonist muscles, length and velocity feedback from muscle spindle, as well as spinal stretch reflex, reciprocal inhibition and recurrent inhibition of Renshaw cells. A descending command modulates the background activation of alpha motoneuron pools in combination with these reflex activities. A static gamma command controls the fusimotor contraction of the spindle. Simulation results reveal that the equilibrium joint angle is linearly correlated to the level of static gamma fusimotor activity of the spindle for a wide range of external loading conditions and reflex gains, suggesting that these spinal reflexes may contribute to regulate the equilibrium position of the joint. Sensitivity analysis further shows that reflex gains and other central commands alter the quasi-linear relation in regular fashions. The reciprocal inhibition gain changes the slope of the linear theta(eq) - gamma curve; and the descending alpha excitation, the stretch reflex gain, and the external load all shift the theta(eq) - gamma curve in parallel. These results imply that reflex gains and descending alpha commands may be coordinated to maintain a unique theta(eq) - gamma curve while providing the flexibility to counteract external loads, to execute a movement, or to regulate additional muscle variables. Dynamic simulation suggests that control of a class of movements can be achieved with a triphasic, alpha pulse and a continuous gamma signal. The model study supports the notion of a dual strategy for controlling trajectories via a feedforward alpha command and for regulating the final equilibrium positions via a feedback gamma command.

Adaptation, Physiological↗
PubMed2005

The specificity and sensitivity of uninhibited COR in labyrinthine-defective patients.

The Cervico-ocular reflex (COR), which depends on proprioceptive afferents from neck muscles to the vestibular nucleus, makes little contribution to the stabilization of gaze in humans. If labyrinthine function is lost because of disease, however, the COR may increase in gain and assume greater importance in generating compensatory eye rotations during natural head movements. We tested the COR, i.e., eye movement responses to rotation of the trunk about the earth fixed head (swinging test with fixed head STFH). If the vestibular function is intact, normally there should be no nystagmus. A total of 88 labyrinthine defective patients and 78 controls were studied. Of the 166 subjects evaluated, 88 presented some kind of alteration (either central or peripheral) and had STFH results showing "no inhibition" in 85 patients. Therefore, the STFH's sensibility is 96.6%. The remaining 3.4% were false negatives (i.e., pathology that could not be detected by the test). Of the 166 subjects evaluated, 78 had normal results and normal STFH. Therefore, STFH's specificity was 100%. We conclude that the study of the COR through STFH is a simple, useful, and clinically reliable test which should improve our knowledge of the interesting relationship between VOR and COR.

Eye Movements↗
PubMed1985

The laryngeal sensory pathway and its role in phonation. A brain lesioning study in the squirrel monkey.

In 10 squirrel monkeys (Saimiri sciureus) uni- or bilateral lesions were placed in the nucl. solitarius, parabrachial nuclei, nucl. ventralis posterior medialis thalami or face area of primary sensory cortex. The effects of these lesions on vocalization were compared with those after transection of the internal branch of the superior laryngeal nerve. It was found that neither the cortical nor thalamic or parabrachial lesions changed the acoustic structure of vocalization. In contrast, destruction of the nucl. solitarius, like transection of the internal branch of the superior laryngeal nerve, affected vocalization severely. It is concluded that the production of species-specific vocalization depends upon a di- or, possibly, tri-synaptic laryngeal reflex control from tactile and proprioceptive laryngeal mechanoreceptors via nucl. solitarius and, possibly, lateral medullary reticular formation to nucl. ambiguus.

Animals↗
PubMed2005

Cobalamin deficiency and subacute combined degeneration after nitrous oxide anesthesia: a case report.

We report on a diabetic man in his early forties with a history of disabling left-hemisphere stroke and hyperhomocystinemia who developed new sensorimotor symptoms and urinary incontinence 4 weeks after prolonged exposure to nitrous oxide (N(2)O) related to arterial occlusive disease and amputation. Physical examination at rehabilitation hospital admission showed preexisting severe nonfluent multimodality language impairment, new ataxic quadriparesis superimposed on static spastic right hemiparesis, diffusely blunted muscle stretch reflexes, impaired cutaneous sensation and proprioception, diminished alternating motion rates, and impaired truncal balance. Laboratory tests revealed low serum cobalamin and hyperhomocystinemia. Magnetic resonance imaging of the spinal cord showed dorsal T2-signal hyperintensity. Treatment included vitamin replacement and comprehensive rehabilitation. His response to hospital-based and outpatient treatment led to successful prosthetic fitting. This case shows the importance of screening for and treating cobalamin deficiency before exposing patients with known risk to N(2)O and highlights the potential diagnostic and therapeutic challenges of subacute combined degeneration when it occurs with a setting of preexisting disabling neurologic impairment.

Adult↗
PubMed2006

Malignant histiocytosis of the brain in three dogs.

Three dogs (two Rottweilers and a Flat-coated retriever) showed various neurological signs, including apathy, depression, circling, a partial decrease in functions associated with cranial nerves, seizures, hyperaesthesia, proprioceptive deficits, and increased spinal reflexes. In all three cases, necropsy revealed a solid, distinct, white mass in the brain and multiple, poorly demarcated, firm nodular proliferations in the lung; in one case the liver was also affected. Histopathological examination showed loosely aggregated, pleomorphic cells, with abundant eosinophilic cytoplasm. The neoplastic cells sometimes contained vacuoles or phagocytized cells. Binucleated and multinucleated giant cells, and mitotic figures, were common. Immunohistochemically, the tumour cells reacted strongly for lysozyme and vimentin, but there was no reaction for S-100 protein, cytokeratin, CD3 or CD79a. The histological and immunohistochemical examinations indicated a histiocytic origin of the tumour cells and malignant histiocytosis was therefore diagnosed.

Animals↗
PubMed2004

Addition of intensive repetition of facilitation exercise to multidisciplinary rehabilitation promotes motor functional recovery of the hemiplegic lower limb.

OBJECTIVE: To evaluate the effects of the intensive repetition of movements elicited by the facilitation technique to improve voluntary movement of a hemiplegic lower limb in patients with brain damage. DESIGN: A multiple-baseline design (A-B-A-B: A without specific therapy, B with specific therapy) across individuals. PATIENTS: The sample comprised 22 subjects with stroke and 2 brain tumour-operated subjects (age: 50.7 +/- 9.6 years, time after onset: 7.1 +/- 2.6 weeks). They were selected from among 165 patients with stroke who were admitted to our rehabilitation centre from September 1, 1995 to March 31, 1997. METHODS: Two 2-week facilitation technique sessions (more than 100 repetitions a day for each of 5 kinds of movement) were applied at 2-week intervals in patients with hemiplegia, who were being treated with continuous conventional rehabilitation exercise without the facilitation technique for hemiplegia. Motor function of the affected lower limb (Brunnstrom Recovery Stage of hemiplegia, the foot-tap test and the strength of knee extension/flexion) and walking velocity were evaluated at 2-week intervals. RESULTS: Significant improvements in Brunnstrom Stage, foot-tapping and the strength of knee extension/flexion of the affected lower limb were seen after the first conventional rehabilitation exercise session and after the first and second facilitation technique and conventional rehabilitation exercise sessions. The improvements after facilitation technique and conventional rehabilitation exercise sessions were significantly greater than those after the preceding conventional rehabilitation exercise sessions. CONCLUSION: Intensive repetition of movement elicited by the facilitation technique (chiefly proprioceptive neuromuscural facilitation pattern, stretch reflex and skin-muscle reflex) improved voluntary movement of a hemiplegic lower limb in patients with brain damage.

Activities of Daily Living↗
PubMed1999

Chronic fenthion toxicity in laying hens.

White leghorn laying hens were exposed to weekly dermal applications of either 1 mg fenthion/kg (FEN; low dose) or 4 mg FEN/kg (high dose) for 24 w with the objective of evaluating chronic FEN toxicity. Four of 24 hens at the high dose exhibited transitory loss of proprioception, perching ability, and righting reflex after 8 to 16 w exposure. All hens receiving the high dose lost the ability or desire to jump from a box during the latter half of the FEN exposure period. Inhibition of serum cholinesterase and brain acetylcholinesterase was greater in the high-dose hens. Brain neuropathy target esterase was not inhibited. Behavioral changes were not correlated with changes in brain concentrations of enzymes or neurotransmitters or their metabolites. Muscle fiber abnormalities were more common in the high-dose hens. Muscle electrical activity was recorded electromyographically via telemetry. Fibrillation (denervation) potentials were absent, but amplitude times duration values for motor unit potentials of the peroneus longus muscle for 5 of the 6 4-w evaluation intervals were higher in the high-dose hens. This EMG response suggested presence of a mild neuropathy which was supported by results of ultrastructural examinations of the sciatic nerve. The low dose initially produced 8% stimulation of egg production while the high dose inhibited egg production 10% during the latter 16 w of the study and reduced body weight 8% during this period.

Acetylcholinesterase↗
PubMed1977

[Neurological complications of Argentinian hemorrhagic fever].

The Argentine hemorrhagic fever (AHF) is an infectious disease, endemo-epidemical, of viral etiology, produced by the Junin virus and limited to the Buenos Aires Province, South of Córdoba, East of La Pampa, and South of Santa Fe. It generally assails rural workers at harvest-time, especially during corn-harvest. The incubation period of the disease does not exceed 12 days. A feverish syndrome with asthenia, adynamia, myalgias, migraine, photophobia, epigastralgia etc., appear. The patient has a facial erythema, petechias on the skin, enantema on the palate, conjunctive micropolyadenopaty injection. The laboratory shows a low erytro, leukopenia with aneosinophilia, thrombopenia and a urine with albuminuria and virous cells. After the fourth day, hemorrhage and a neurological case appears. The laboratory tends to normalize and cast appears in the urine. The most striking neurological signs are the following: muscular hypotonia, proprioceptive hyporreflexia or arreflexia, marinesco reflex, shakings, difficulty to stand and walk, oscillations in consciousness level, and ocular disturbances. The cytochemical test of the C.L. Rachis in the usual ways of the AHF is within its normal characteristics; on the other hand there are modifications in the nervous cases: the total proteins are nearly always increased and the cells augmented with a great predominance of mononuclear cells. The electroencephalogrammes were always abnormal, varying from a brief disorganization up to a diffusive and permanent slowness. The half of which additionally presented paroxisms generalized by slow waves. The pathological anatomy over the central nervous system makes us think that the lesion would not primitively neuronal but that the action of the virus would be indirectly done through the capillar wall. This capillar lesion is produced by multiple focuses. The neuronal destruction with necrosis by microinfarcts is minimum. The symptoms and neurological signs are present in 10% of the clinical cases; the death-rate in the nervous clinical cases having reached 50% of them. The premature treatment allows the death-rate to diminish and the cases that survive have not many after effects.

Adult↗
PubMed1999

Predicting vestibular, proprioceptive, and biomechanical control strategies in normal and pathological head movements.

Little is known of the functionality of the vestibulocollic reflex (VCR) and cervico-collic reflex (CCR) during head and neck movements caused by perturbations of the trunk. Previously, we formulated mathematical expressions for these neck reflexes and incorporated them into a model of horizontal plane head movements. The formalism of this neuromechanical model allowed us to examine separately the main components of head movement control. In the present study, we examine selected parameters within the main components of the model, and associate variations of these parameters with disease processes affecting head and neck movements, such as loss of sensory input or modification in central or motor function. Our simulations led us to several conclusions. First, the probable use of the VCR and CCR in yaw plane head movements is to tune the head response. In the time domain, they diminish natural head oscillations (head wobble) related to head mechanics. Equivalently, in the frequency domain, they reduce the amplitude of head wobble (resonances) around 2 Hz. Second, our simulations suggest that the VCR is about ten times stronger than the CCR in normal humans. Moreover, this disproportion is associated with only very minor contributions from the CCR in yaw. Third, head oscillations (or instability) can be generated by mechanical or neural changes in the head and neck system. Finally, readjustments of central nervous system dynamic operations could provide mechanisms to compensate for sensory and motor dysfunction caused by disease.

Adult↗
PubMed1999

Joint reposition sense in subjects with unilateral osteoarthritis of the knee.

OBJECTIVE: To identify the sensory deficit of partial weight-bearing joint repositioning sense in subjects with unilateral osteoarthritis (OA) of the knee. The methodology was developed to incorporate measures made easily in a clinical setting. In OA, local degenerative changes can affect the function of sensory receptors and mechanoreceptors. As a result, appreciation of limb position as well as function may be compromised. Because proprioceptive sense plays an important role in reflex muscle contraction and stabilization of the joint, functional stability and joint integrity may be at risk if proprioception is impaired. DESIGN: Twenty subjects with unilateral OA of the knee were age-matched with 20 controls for the purpose of this study. The difference in degrees between a target angle of knee flexion and a reposition angle was measured during a partial weight-bearing test. A Dualer (electronic dual inclinometer) was used to measure the joint reposition sense (JRS) of the knee. Both sides were tested with six repetitions on each side. A mixed-model ANOVA was applied to the data for analysis. RESULTS: Comparison of the JRS between groups revealed a significant difference, with OA subjects having higher JRS error (JRSE) (p <0.001) than controls. There was no significant difference in JRSE for either side, regardless of group. CONCLUSIONS: Subjects with unilateral OA of the knee demonstrated poorer performance on both legs in a partial weight-bearing reposition test than did control subjects.

Female↗
PubMed1986

The nature of reverse phase reflex eye movement.

The unusual phenomenon of reverse phase reflex eye movement was first described by Ishikawa. In this study the reflex frequency response was examined by electrooculography. In typical cases a reflex was observed by repeated forced duction up to 9 Hz. As a result it was postulated that proprioception is usually involved in reverse phase reflex eye movement, because visual eye movement cannot respond to a movement beyond 1 Hz. When the lag-times between the peaks of forced duction in one eye and those of the reflex movement in the other were measured, they were almost zero or even negative at high frequencies of forced duction as 6 and 9 Hz. This phase advance of the reflex movement was explained only when the receptor of the reflex had a dynamic response, because 90 degrees phase advance results in a reflex through such a receptor. The primary ending of muscle spindle represents such a receptor. The magician's forceps phenomenon as first discovered by Mitsui in exotropia is supposed to be a blocking reflex through the tendon organ. The transmission lag-times of both reflexes can be as short as 20 msec, but must be slightly longer to consider them to be monosynaptic.

Adolescent↗