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PubMed2000

An examination of the synergistic interaction of ethanol and thiamine deficiency in the development of neurological signs and long-term cognitive and memory impairments.

BACKGROUND: The prolonged and heavy consumption of ethanol has been associated with thiamine deficiency and a wide range of cognitive and memory impairments. The present study was undertaken to test the hypothesis that ethanol and thiamine deficiency act synergistically, producing more severe clinical neurological disturbances and cognitive and memory impairments than either thiamine deficiency or chronic ethanol alone. METHODS: The acute neurological and long-term behavioral consequences of combined chronic (32 weeks) ethanol consumption (20% v/v in drinking water) and three separate 4-week long episodes of dietary thiamine deficiency (ET/TD) versus ethanol (ET) or thiamine deficiency (TD) treatments alone were examined in male Sprague Dawley rats aged 12 weeks at the start of treatment. RESULTS: The ET/TD group lost less weight than the TD group during each episode of thiamine deficiency. Contrary to expectations, the progression and severity of ataxia, impaired righting reflexes, and opisthotonic posturing were similar in the ET/TD and TD groups. None of the ET animals displayed any neurological or behavioral symptoms during treatment. After withdrawal from ethanol and a 7-week recovery period, none of the groups differed in spontaneous activity. On subsequent testing, the ET group displayed a significant increase in perseverative responding in a spontaneous alternation task. A small but significant proportion of ET/TD (23%), ET (17%), and TD (8%) animals were unable to reach criterion on an initial nonmatching-to-position task (NMTP) or in two subsequent reversals of the matching and NMTP tasks, which indicated persistent learning impairments. A large proportion of animals in each of the three groups demonstrated significantly reduced accuracy compared with controls at longer delays of matching-to-position tasks (MTP), but only the ET group was consistently impaired at the shorter delays. There were no significant correlations between blood ethanol concentration and any of the learning and memory measures. CONCLUSIONS: These results indicate that the interaction of chronic ethanol consumption and bouts of TD is both domain specific and not always synergistic. Learning and reference memory appear to be sensitive to a synergistic interaction of ET and TD, whereas short-term working memory disturbances are most affected by ET and neurological symptoms are most associated with TD. Furthermore, neither the presence of neurological symptoms nor blood ethanol concentrations appear to be good predictors of learning and memory deficits.

Animals↗
PubMed2000

Ginkgo biloba: local experiences.

Ginkgo biloba (EGb 761) as a phytotherapeutic agent used in otoneurology, psychiatry, and ophthalmology. We studied the efficacy of therapy with EGb 761 in 72 patients (44 male and 28 female) with chronic cochleovestibular disorders. We used pure-tone audiology, measuring pure-tone average, speech reception threshold, and speech discrimination score. Then we used craniocorpography to measure lateral body sway and angular deviation. Finally, we used nystagmography (central nystagmic frequency). Also, we assessed subjectively the variation in patients' comfort. We concluded that EGb 761 has a very good effect on both postural and oculovestibular reflexes. Also, hearing was improved, and patients' comfort was considered to be heightened by the therapy.

Audiometry↗
PubMed2004

Measurement of the cutaneous blood flow reserve in normal humans by laser-Doppler flowmetry.

AIM: To assess the normality of the cutaneous blood flow reserve (CR). METHODS: To explore the feasibility and reproducibility of laser-Doppler flowmetry for CR measurement, we prospectively measured CR in 17 healthy subjects on the dorsum of the foot and pulp of the big toe. CR was defined as the sum of the venoarteriolar reflex (VAR), i.e. postural vasoconstriction, and postischemic reactive vasodilation (H), expressed as % of the resting supine flux and assessed by using laser-Doppler flowmetry. RESULTS: For the dorsal foot, VAR%+/-SEM was 61+/-14, H%, 752.5+/-214 and CR, 813.5+/-217. On the pulp of the big toe, VAR% was 61.6+/-4.7, H%, 588.2+/-174 and CR, 649.9+/-176. CR measurement variability was assessed by calculating the inter-individual coefficient of variation of CR, which was 1.1 for both the dorsal foot and pulp of the big toe. Reproducibility was assessed by calculating the CR intraclass correlation coefficient, which was 0.49 for the dorsal foot and 0.64 for the pulp of the big toe. CONCLUSIONS: The CR is proposed as a new parameter for assessing the microvascular integrity and contractile reserve of the skin. Laser-Doppler flowmetry is suitable for this non-invasive evaluation. The method displayed large variability, and its reproducibility varied from moderate for the dorsal foot, to substantial for the toe. Further studies are necessary to demonstrate its clinical usefulness.

Blood Flow Velocity↗
PubMedDate not supplied

[The usefulness of tizanidine. A one-year follow-up of the treatment of spasticity in infantile cerebral palsy].

INTRODUCTION: The cerebral palsy has the first place of physical handicap in children (type spastic, 88%). Tizanidine imidazole derivative is centrally acting as a a2-adrenergic agonist. AIM: To demonstrate clinically the effectiveness of tizanidine in the decrease of the spasticity. PATIENTS AND METHODS: We assigned randomly in a double blind study 10 children treated with tizanidine (0.05 mg/kg/day) and 30 with placebo for a 6-month period, after which they were unified in the group of tizanidine. The dependent variables were spasticity, Ashworth scale, posture tone scale, reflex scale and liver function test. RESULTS: The spasticity and the reflex decreased in the group of tizanidine an 78.85% in comparison with a 7.64% in the group of placebo (p = 0.0001); in the monitoring of 6 months 35 patients reduced this to 78.2% (p= 0.0001). The duration of effectiveness of tizanidine in four patients was two months and they never returned to their appraisal basal. Without reported adverse effects, the liver function test remains normal. CONCLUSION: Tizanidine produces a significant reduction of the spasticity in children without adverse effects, having a high percentage of acceptance to the prescribe dose.

Adolescent↗
PubMedDate not supplied

[Cervicogenic proprioceptive vertigo: etiopathogenesis, clinical manifestations, diagnosis and therapy with special emphasis on manual therapy].

Cervical proprioceptive system (CPS) consisting of mechanoreceptors of cervical intervertebral joints, mechanoreceptors of neck muscles and ligament's insertions, muscle spindles located in deep short muscles of cervical spine and sensitive fibers connecting neck's proprioceptors with neurons of cornu posteriori of spinal cord, plays an essential part in maintaining bodily balance. CPS, via tractus spinovestibularis, is connected to vestibular nuclei. Clinical and neurophysiological studies have shown that functional disorders and/or organic lesions of CPS cause identical symptoms as vestibular diseases: vertigo, nystagmus and balance disorders. Dysfunction (functional blockade) of craniocervical joints is the most frequent cause of cervicogenic proprioceptive vertigo (CPV). The constant tension of the capsule of a blocked joint irritates mechanoreceptors protecting the joint's capsules. The increased activity of mechanoreceptors results in confusion of vestibular system. That is, the impulses from the blocked craniocervical joints do not correspond to the impulses from the vestibular organ and other sensory systems that take part in maintaining bodily balance. The disharmony of impulses results in an inadequate vestibulo-spinal and vestibulo-ocular reaction manifesting as vertigo and nystagmus. Hyperactivity of craniocervical mechanoreceptors also causes disturbances in reflex regulation of postural muscle tonus manifesting as "general instability". Knowledge of CPV as a separate clinical entity is important from diagnostical and therapeutical aspect. As it concerns a peripheral vestibular disorder still unknown to a wider circle of physicians, the article describes etiopathogenesis, clinical manifestations, diagnosis and therapy of CPV with special emphasis on manual therapy.

Cervical Vertebrae↗
PubMed1991

Effects of occupied and unoccupied bed making on myocardial work in healthy subjects.

Strict bed rest prescribed after acute myocardial infarction provides rest for the heart in an effort to lessen myocardial work. However, bed rest has been implicated as a threat to physical and psychosocial well-being. Nurses must question whether activities associated with bed rest, such as bed making by hospital personnel while the patient is occupying the bed, actually require less myocardial work than out-of-bed activities. In this study we examined cardiovascular function of 22 healthy individuals, 10 (45.5%) men and 12 (54.5%) women ranging in age from 34 to 69 years (mean 48 years), during occupied (side to side method) and unoccupied (patient up to chair) bed making. Cardiac output, heart rate, stroke volume, systolic blood pressure, diastolic blood pressure, mean arterial pressure, total peripheral resistance, and the ratio of preejection period to left ventricular ejection time were measured by using an impedance cardiograph and vital signs monitor. Although differences between these measurements during the two bed making procedures were statistically significant (p less than 0.001), they were not deemed clinically significant for healthy subjects because they represent transient reflexive responses to posturally induced changes in venous return rather than substantial increases in myocardial work. When the goal is minimal myocardial energy expenditure, making the bed when it is unoccupied may offer a sound alternative to making an occupied bed.

Bed Rest↗
PubMed1988

Intracranial dermoid cyst in a dog.

A 7-year-old spayed bitch had a 3-year history of episodes of hind-limb weakness and ataxia. Neurologic abnormalities consisted of deficits in postural reactions, spinal reflexes, and conscious proprioception. A right-sided head tilt also was observed. Immediately after cervical radiography, CSF tap, and electroencephalography, the dog was alert, but it was found comatose the next morning and died within an hour. At necropsy, a 1.6- x 0.8- x 1.5-cm, thinly encapsulated mass was found on the left cerebellar peduncle. It had caused dorsal displacement of the left portion of the cerebellum and ventral compression of the fourth ventricle. Histologically, the mass was determined to be a dermoid cyst.

Animals↗
PubMed1987

Inhibitory interactions between spiking and nonspiking local interneurons in the locust.

Simultaneous intracellular recordings were made from pairs of spiking and nonspiking local interneurons in the metathoracic ganglion of the locust to search for interactions that might underlie tactile and proprioceptive reflexes of a leg. A spike in a spiking local interneuron is followed after a consistent latency (0.6 +/- 0.12 msec, mean +/- SD) by an IPSP in a particular nonspiking interneuron. The connection appears to be direct and chemically mediated. By contrast, manipulating the membrane potential of a nonspiking interneuron by injecting current through the recording electrode has no direct effect on a spiking local interneuron. The direct interactions between pairs of these local interneurons are thus one-way. If, however, the current injected into a nonspiking interneuron is sufficient to evoke a movement by exciting motor neurons, then the spiking interneuron can be excited or inhibited by the resulting reafference. The spiking local interneurons have excitatory regions in their receptive fields formed by arrays of exteroreceptors or by proprioceptors at specific joints. The inhibitory connections mean that the postsynaptic nonspiking interneurons have corresponding inhibitory regions to their receptive fields. Several spiking local interneurons with similar receptive fields may converge onto one nonspiking interneuron. Some nonspiking interneurons, however, have larger receptive fields than an individual spiking interneuron, again indicating convergence of inputs. The specificity of the inhibitory connections preserves the spatial representation of sensory information for use in particular reflexes. For example, touching hairs on the ventral femur evokes a reflex extension of the tibia. Spiking interneurons excited by these receptors inhibit a nonspiking interneuron that would cause the opposing and therefore unwanted flexion movement. Viewed in this behavioral context, the pattern of connections between the local interneurons forms the basis of the circuitry for the local reflex adjustments of posture and locomotion.

Action Potentials↗
PubMed1983

Indoramin in the treatment of hypertension. A mini-review and update.

The origins, preclinical development and clinical pharmacology of a new antihypertensive agent, indoramin (Baratol; Wyeth), are briefly reviewed. Indoramin is a competitive postsynaptic alpha-adrenoceptor antagonist with a myocardial membrane-stabilizing component of action. These features are believed to be responsible for its antihypertensive efficacy. They may also explain the absence of problems common to older alpha-blockers such as reflex tachycardia and postural hypotension. Clinical evaluation of a new agent such as indoramin in the management of hypertension is discussed in terms of efficacy, dosage regimen, tolerance, adverse effects, interactions, withdrawal syndrome, and long-term influence on the complications of high blood pressure.

Animals↗
PubMed1983

[Early complex rehabilitation of children with cerebral palsy].

The aim of a study was to evaluate health, psychological and social problems related to rehabilitation of cerebral palsy children (c.p. children). The study was based on 30 children c.p. who after diagnosis underwent systematic complex rehabilitation. Half of the children was under observation in outpatient clinics and their parents played the role of physiotherapeutists another half of the children apart from ambulatory kind of rehabilitation was hospitalized periodically in rehabilitation centres. Each half year all the children underwent control examinations of physical and motor development (including evaluation of postural and righting reflexes) as well as of psycho-motor development. Environmental conditions, parental attitudes towards examined children taking into consideration their evolution were also evaluated. The therapeutic team consisting of a paediatrician, neurologist, psychologist, physiotheraupeutist and psychiatrist took advantage of these examinations in psychotherapy of parents. Observation period of children was from 1:6 to 3 years. Age when rehabilitation was initiated was below 20 months of life. It was observed that result are influenced mainly by the degree of neurological disorders not by the conditions of rehabilitation. There are differences with regard to motor efficiency between rehabilitation at home and in rehabilitation center. Treatment at home has a better effect upon psychomotor development of children with more serious developmental disorders. Infections of upper respiratory tract are more rare in this group of children. There are two reasons why children in preschool age should be recommended for sanatorium treatment: medical indication e.g. operation and social indications.

Cerebral Palsy↗
PubMed1994

[Olivopontocerebellar atrophy and Parkinson's disease: diagnostic problems].

Clinical diagnoses of Parkinson's disease (PD) is highly inaccurate. Olivopontocerebellar atrophy (OPCA) is a major source of diagnostic confusion. We have studied the clinical characteristics of 50 patients with PD, 24 patients with OPCA judged by the presence of selective atrophy of the cerebellum and brainstem (diagnosed by CT brain scan) and 30 normal controls of similar age. The typical triad of PD, tremor, rigidity and akinesia, did not distinguish among patients from either group. The presence of severe postural imbalance and reflex myoclonus (in OPCA but not in PD) were the 2 most highly discriminative clinical features.

Aged↗
PubMed1976

[Experimental study of vestibular neurectomy].

The authors describe an experimental study carried out on baboons. After unilateral vestibular neurectomy, the behaviour disorders on the one hand, and on the other, modifications and temporal development of reflex muotatic excitability of the spine using Hoffmann's reflex method are analyzed. As far as behaviour is concerned, a four-day period of motor restriction following the operation causes more marked residual disorders in comparison with controls. From the neurophysiological point of view, neurectomy results in seriously disordered spinal reflexes characterized by ipsilateral hypo-excitability developing in there stages: a tw-day initial critical phase during which the disorders are at their worst, a four-day recuperative stage with partial regression of the disorders, finally a chronic compensation stage in which spinal excitability returns to normal after several months.

Animals↗
PubMed1997

Use of electromyography in seven injured wild birds.

Seven wild birds with traumatic injuries affecting the peripheral nervous system were evaluated with the aid of electromyography. Initially, electromyography was performed on these birds because of loss of motor control and muscle atrophy that could not be explained by clinical signs alone. It can be difficult to assess postural reactions and reflexes in these birds. Use of electromyography to provide prognostic information for rehabilitation potential had not been reported. Reviews in the literature indicate that electromyography in human beings helps when assessing prognosis in sports-related injuries. Because wild birds require nearly total function for complete rehabilitation, electromyographic findings of functional motor units or evidence of axonal degeneration can assist in determining their potential for release.

Animals↗
PubMed1991

Disturbed modulation of the stretch reflex gain during standing in cerebellar ataxia.

The postural control disturbance in patients with spino-cerebellar degeneration (SCD) was evaluated by the displacement of the center of foot pressure (CFP) and the amplitude of the triceps surae muscle H reflex in various standing postures. Twelve patients and 8 age-matched normal subjects (NL) were studied. The CFP, surface electromyograms (EMG) in the lower leg and the soleus H reflex were recorded in all subjects. The CFP displacement area was recorded in 10 patients. The following results were obtained: (1) the range of displacement of CFP from forward to backward leaning as a fraction of foot length was significantly smaller in the patients than in the controls (mean +/- S.D.; SCD = 52.8 +/- 12.7%; NL = 62.3 +/- 9.9%; P less than 0.05%, Student's t test); (2) the ratio of the increase in amplitude of the H reflex to soleus muscle EMG activity when the subjects leaned forward from an upright posture was significantly higher in the patients than in the controls (SCD = 0.41 +/- 0.40; NL = 0.17 +/- 0.15, P less than 0.05); (3) this ratio correlated with the area of CFP displacement during upright standing in the patients (r = 0.75, n = 10, P less than 0.05). These results indicate that the suppression of the stretch reflex observed in normal controls during standing is impaired in patients with SCD. We conclude that a decreased suppression of the stretch reflex is one of the mechanisms responsible for the instability on standing in patients with SCD.

Adult↗
PubMedDate not supplied

The reliability of H-reflex recordings in standing subjects.

OBJECTIVE: Several studies have used the H-reflex to investigate the effect of upright stances and locomotion on spinal reflex excitability. The reliability of eliciting this reflex during weight-bearing has however yet to be addressed. This study was undertaken to determine the reliability of individual differences in the H-reflex recorded from healthy subjects during quiet standing. Secondary aims of the study were to evaluate individual reliability during prolonged standing, and to establish the minimum number of trials required to provide reliable measurements of the H-reflex. DESIGN AND PARTICIPANTS: Twenty neurologically healthy volunteers participated in a repeated measures design consisting of 8 blocks of 20 trials evenly distributed over two testing sessions. H-reflex recordings were elicited from the subject's dominant side soleus muscle by percutaneously stimulating the posterior tibial nerve. Stimuli were presented every 10 s, with 2 min seated rest provided between blocks of trials. Peak-to-peak amplitude of H-reflexes and m-responses determined for individual trials were used for subsequent analysis. RESULTS: It was found that the reliability of measuring the H-reflex and m-response during quiet standing was extremely robust (r = .97 for both measures). This pattern of individual differences remained consistent over 80 trials confirming the stability of the measures. High reliabilities (r = .96 and .87 for the H-reflex and m-responses respectively) were also observed when as few as four trials were analysed. When measures obtained during the first session of testing were compared with those obtained for session two, the correlation coefficients were generally of a lower order (r = .54 to .90). DISCUSSION: The results demonstrate that the H-reflex in quiet standing provides high intra-individual reliability, suggestive of a stable reflex resistant to potentially confounding postural influences, or other sources of biological variation. The between-session reliability underscores the difficulty in reproducing conditions between sessions, and emphasises the need for within-session comparisons of H-reflex amplitudes. Given the functional challenge of maintaining an upright posture, the H-reflex appears to be a well maintained and stable phenomenon.

Adolescent↗
PubMed1999

Anatomical observations of the rat cerebellar nodulus after 24 hr of spaceflight.

Exposure to microgravity causes alterations in postural, locomotor and oculomotor functions. The vestibular abnormalities experienced by astronauts entail immediate reflex motor responses, including postural illusions, sensations of rotation, nystagmus, dizziness and vertigo, as well as space motion sickness. Adaptation to the microgravity environment usually occurs within one week, and a subsequent re-adaptation period of several months is often required upon return to Earth. Some astronauts experience recurrences of dizziness, nausea, and vomiting, as well as marked disturbances in postural equilibrium in the absence of vision during this readaptation period. The mechanisms underlying such adaptation processes remain unclear, although current evidence favors some type of sensory conflict. The purpose of the present study was to explore the structural basis for the reorganization in the central vestibular system that underlies the process of adaptation to altered gravitational environments. Hindbrain tissue was obtained from rats flown on the Neurolab shuttle mission (STS-90) that launched on April 17, 1998. Tissue for the present report was obtained from four adult Fisher 344 rats sacrificed on orbit during flight day 2 (FD2), 24 hr after launch. Equal numbers of vivarium control animals and cage-controls were sacrificed 48 and 96 hr, respectively, after the flight dissections. Following decapitation, each hindbrain was immersion-fixed for 45 min in 4% paraformaldehyde/0.1% glutaraldehyde in 0.1M phosphate buffer pH 7.3, and then transferred to a 4% paraformaldehyde solution in 0.1M phosphate buffer for 18 days at 4 degrees C. After this fixation, the cerebellum was dissected away from the ventral portion of the brainstem by severing the cerebellar peduncles. The entire cerebellum of each rat was cut by Vibratome into 100 micrometers thick sections in the parasagittal plane. These sections were collected serially and processed for electron microscopy by osmication, dehydration in a graded series of methanol solutions, infiltration with resin, and embedment in Epon-Araldite resin between plastic coverslips.

Adaptation, Physiological↗
PubMed1990

Postural maintenance during movement: simulations of a two joint model.

Voluntary movements of the upper body are accompanied by anticipatory postural adjustments to the lower body in a standing subject. The long-standing hypothesis is that these anticipatory adjustments serve to counteract the perturbation to the body's center of gravity caused by the voluntary arm movement. This paper presents model simulations investigating the possible roles of anticipatory postural activity that accompanies a rapid, upward arm swing. The model incorporates two (idealized) antagonistic muscle pairs controlling the movements of a double-joint system, with a "shoulder joint" between the arm and stiff body links, and an "ankle joint" between the stiff body-leg segment and the ground. Each muscle is represented by a nonlinear viscoelastic element and also includes proprioceptive feedback. Four inputs to the model define the motor control signals for muscle force generation in both the arm and the postural muscle pairs. The neurological component of the model describes consequences of alternate strategies for cocontractions, stretch reflex activity, and anticipatory and synchronous postural activities (or combinations thereof). Simulations with this model show that: (1) none of the postural maintenance schemes considered in these simulations (including varying anticipation) could suppress the initial backward thrust on the body link; (2) the more important destabilizing perturbation is a subsequent forward sway that, left uncountered by postural activity, would eventually leave the body to fall flat on its face; and (3) anticipatory silencing of the postural extensor followed by a brief period of extensor activation (descending control) and synchronous reflex activity (feedback control) appears to be the most likely postural stabilizing strategy that inhibits the continuous forward sway and is consistent with the experimental evidence.

Arm↗