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[Bulbar hematoma of the olivary area. An analysis of the autonomic syndrome].

The consequences of an anterolateral medullary hematoma in a 50 year old patient are reported. The lesions principally involved the inferior olive nuclei, the lateral reticular nucleus, and, partially, the nucleus ambiguus. Long-lasting postural control deficit and hypotonia were observed, associated with alpha motoneurons hyperexcitability. Analysis of the heart rate regulation showed a severe reduction of the normal accelerating reactions and a relative preservation of slowing down reactions that suggested a deficit of the ortho-sympathetic control. Unilateral palsy of the tongue and pharynx was also observed without sensory or sensorial deficit. The long term course was favourable.

Autonomic Nervous System Diseases↗

[Computerized stabilometry in the monitoring of antiepileptic therapy in children].

Computerized stabilometry is an useful test to monitor postural effects of anticonvulsant therapy in adults. Our study was carried out on 65 epileptic children: 51 were treated with CBZ or PHT or VPA or PB in monotherapy, and 14 were not on therapy, in the aim to observe abnormalities of postural control in pediatric population. Computerized stabilometry has to be considered auxiliary monitoring to evaluate toxic effect of anticonvulsant therapy in children.

Anticonvulsants↗

Effects of jumping skill training on walking balance for children with mental retardation and Down's syndrome.

UNLABELLED: In the present study, we hypothesized that the enhancements obtained from the practice of jumping activity could be transferred to improve the walking balance in children with mental retardation (MR) and Down's syndrome (DS). SUBJECTS: Fourteen children with the diagnosis of MR or DS, aged 3 to 6 years, were recruited from a day care institution. They were ambulant but without jumping ability. Sixty-one non-handicapped children was used to serve as a normative comparison group. METHOD: Before the training program, the performances of walking balance, jump skills and jumping distances were assessed individually by one physical therapist. The balance sub-test in the Bruininks Oseretsky Test of Motor Proficiency (BOTMP) was administered to assess the walking balance. Motor Skill Inventory (MSI) was used to assess the qualitative levels of jumping skills. A jumping skill training lesson that included horizontal jumps and vertical jumps was designed and integrated into the educational program. The recruited children received 3 sessions of training per-week for 6 weeks. A post-training test and a follow-up test were administered to the handicapped children. RESULT: In BOTMP scores, statistical differences exited between the pre-training and post-training tests in the tested items of floor walk and beam walk. However, no significant difference was found in the items of floor stand, beam stand and floor heel-toe walk. MSI scales revealed there were significant differences between pre-training and post-training tests. There was no significant difference between the scores of post-training test and the follow-up test. DISCUSSION: The results implicated that the jumping activity might effectively evoke the automatic and dynamic postural control. Moreover, the significant improvements of the floor walk and beam walk performances might be due to the transferred effects via the practice of dynamic jumping activity. Furthermore, implications and suggestions are discussed.

Child, Preschool↗

Effect of balance training on recovery of stability in children with cerebral palsy.

This study examined the effect of massed practice in balance recovery of stability in six children (four males, two females; mean age 9 years 2 months, SD 2 years, range 7 years 5 months to 12 years 11 months) with cerebral palsy (CP). Four children were diagnosed with spastic diplegia (Gross Motor Function Classification System [GMFCS] level II) and two with spastic hemiplegia (GMFCS level I). A single-subject, multiple-baseline experimental design involving three pairs of children matched for diagnosis was used. A moveable forceplate system was used to test and train reactive balance control. Area per second (i.e. area covered by the center of pressure over a one second period) and time to stabilization from center of pressure measures were calculated following perturbations. The intervention phase consisted of massed practice on the moving platform (100 perturbations/day for 5 days). Analysis included hierarchical linear modeling and a repeated measures ANOVA. All children demonstrated a significant improvement in their ability to recover stability as demonstrated by reduced center of pressure area and time to stabilization following training. These improvements were still present 30 days following completion of training. Results suggest that postural control mechanisms in school-age children (7 to 13 years) with CP are modifiable.

Adolescent↗

Postural adaptation in elderly patients with instability and risk of falling after balance training using a virtual-reality system.

Our aim in this study was to assess postural control adaptation quantitatively in unsteady elderly patients at risk of falls in open spaces and given balance training with a virtual-reality system reproducing environmental stimulation. Using a balance rehabilitation unit based on a virtual-reality system that changes sensory information (visual, vestibular, and somatosensory), we treated 26 elderly, unsteady patients who were prone to falling (age range, 73-82 years) and who were enrolled in a customized vestibular rehabilitation program. We assessed postural responses by posturography before and after 6 weeks in the vestibular rehabilitation program under two conditions: (1) standing, eyes open, static visual field, and (2) standing, eyes open, dynamic visual field through virtual-reality goggles, generating horizontal optokinetic stimulation (70 degrees per second angular velocity). We recorded postural responses with a platform measuring the confidential ellipse of the center-of-pressure distribution area and sway velocity with a scalogram analyzing postural behavior by wavelets. After 6 weeks of treatment, postural response confidential ellipse and sway velocity values were lower, evincing decreased amplitudes and sway frequency contents in the scalogram by wavelet under both stimulation paradigm conditions. These findings suggest postural adaptation under the two perceptual conditions when patients had static and dynamic visual fields. The possibility of treating elderly fallers with balance disorders using a virtual-reality environmental stimulation reproduction system is discussed.

Accidental Falls↗

Elevated heels and adaptation to new shoes in frail elderly women.

Footwear is supposed to have influence on postural control and is a potential aspect to address in the prevention of falls in the elderly. This study aimed to show whether measurements of static balance and gait are different with habitual shoes compared to new special senior shoes with different heel height and whether these results change after adaptation. In a randomized controlled intervention study, 26 subjects (median age 87 years) were recruited from two nursing homes and one facility of assisted living. Measurements of static balance and gait were performed with habitual shoes and two types of new special senior shoes differing in heel height. Measurements were repeated after five weeks. There was no difference in static balance and gait with habitual shoes compared to either of the new footwear offered. Results of performance with higher heels were not different compared to lower heels. No further effect of adaptation after wearing a new shoe over five weeks could be demonstrated. With respect to static and dynamic balance, there seems to be a wide range of acceptable footwear as long as the heel height is below a critical value. A standardized shoe can be used in the assessment of balance because the effect of adaptation can be neglected.

Accidental Falls↗

Genetic control of acute ethanol-induced behaviors in Drosophila.

BACKGROUND: In most organisms in which acute ethanol exposure has been studied, it leads to similar changes in behavior. Generally, low ethanol doses activate the central nervous system, whereas high doses are sedative. Sensitivity to the acute intoxicating effects of ethanol is in part under genetic control in rodents and humans, and reduced sensitivity in humans predicts the development of alcoholism (Crabbe et al., 1994; Schuckit, 1994). We have established Drosophila melanogaster as a model organism to study the mechanisms that regulate acute sensitivity to ethanol. METHODS: We measured the effects of ethanol vapor on Drosophila locomotor behaviors by using three different assays. Horizontal locomotion was quantified in a locomotor chamber, turning behavior was assayed in narrow tubes, and ethanol-induced loss of postural control was measured in an inebriometer. Mutants with altered sensitivity to the acute effects of ethanol were generated by treatment with ethyl methane sulfonate and isolated by selection in the inebriometer. We ascertained the effects of these mutations on ethanol pharmacokinetics by measuring ethanol levels in extracts of flies at various times during and after ethanol exposure. RESULTS: Among nearly 30,000 potentially mutant flies tested, we isolated 19 mutant strains with reduced and 4 strains with increased sensitivity to the acute effects of ethanol as measured in the inebriometer. Of these mutants, four showed changes in ethanol absorption. Two mutants, named barfly and tipsy to reflect their reduced and increased ethanol sensitivity in the inebriometer, respectively, were analyzed for locomotor behaviors. Both mutants exhibited ethanol-induced hyperactivity that was indistinguishable from wild type. However, barfly and tipsy displayed reduced and increased sensitivity to the sedative effects of ethanol, respectively. Finally, both mutants showed an increased rate of ethanol-induced turning behavior. CONCLUSIONS: The effects of acute ethanol exposure on Drosophila locomotor behaviors are remarkably similar to those described for mammals. The analysis of mutants with altered sensitivity to ethanol revealed that the genetic pathways which regulate these responses are complex and that single genes can affect hyperactivity, turning, and sedation independently.

Absorption↗

Posturography in vestibular work-up of the patient. A review.

In order to obtain a complete functional balance in the patient suffering from vestibular disorders it is necessary to examine the spinal reflexes. Computerized posturographic systems allow quantitative and qualitative analysis of body sway. The posturographic test must be preceded by an accurate clinical examination to identify the anomalies of the osteo-arthro-muscular structure that can cause disorders in motor programs and in proprioceptive inputs. A battery of complementary posturographic tests can clarify the influence of the vestibular, proprioceptive and visual inputs. The posturographic tests allow us: to observe particular aspects of postural control which are not usually detected by the common clinical examination; to identify the most correct kind of functional reeducation and to monitor the spontaneous evolution of the disease and the results of the therapy; to show the voluntary simulators or accentuators of unsteadiness in medico-legal reports.

Humans↗

[New approaches to diagnosis of hysteria].

Postural stability or fluctuation of general centre of gravity (GCG) was investigated in 14 patients with hysteric motor disorders(alterations of statics and walking, pseudopareses) by means of stabilograph. Comparative groups included 7 patients with hemipareses of vascular origin, 7 patients with multiple sclerosis with spastico and atactic disturbances and 7 healthy individuals. The amplitudes of GCG fluctuations in both sagittal and frontal planes as well as their correlations were analysed. It was shown that amplitude of GCG vibration was maximal in hysteriac patients. However patterns of regulation of postural control in hysteriac patients (correlation of amplitudes of vibrations in sagittal and frontal planes) were similar to those of healthy individuals and differed significantly from organic models.

Adult↗

A computer-controlled system to perturb the ankle joint of freely standing cats trained to maintain a given force.

A computer-based system was developed to (1) train freely standing cats to match various target forces with the left hindlimb, (2) perturb the left ankle joint when the cat was maintaining a desired force and (3) compare reflex responses before and after decerebration. Cats quickly learned to stand unaided on 4 pedestals. During a training session, a range of target force windows was presented to the cat. A successful trial consisted of maintaining the force applied on the left rear pedestal within the target window for a preset time period. To assist the cat, a light was turned on whenever the force was within the target window. A food pellet reward was delivered by the computer after each successful trial. To test reflex responses, the position of the left hindlimb could be briefly perturbed by activating a servo-controlled printed motor configured to rotate the pedestal about the axis of the ankle joint. Perturbations that either flexed or extended the ankle joint were presented pseudo-randomly by the computer. This approach has been used to quantify the magnitude of muscle afferent volleys and the reflex EMG in ankle extensor muscles of normal and decerebrated cats, in response to similar mechanical perturbations. It has also been used to study dynamic features in the electroneurogram recorded from a cutaneous nerve by implanted nerve cuff electrodes, and the correlations among the electroneurogram, the vertical contact force applied on the pedestal and the force recorded from muscle tendons by implanted transducers. This approach may have general applications in the study of postural control, including the study of the discharge patterns of individual motor, sensory or spinal cord neurons in freely standing cats.

Animals↗

Central set influences on gait. Age-dependent effects of postural threat.

We tested the hypothesis that anxiety regarding the potential consequences of a possible fall would alter gait patterns differently between younger and older adults. Sixteen younger and fifteen older adults participated in this study. Participants walked at a self-determined velocity along a 7.2-m walkway under 4 different conditions of postural threat; the walking conditions varied depending on the width constraints of the walkway (0.60 m vs 0.15 m) and the height of the walking surface (floor vs elevated: 0 m vs 0.60 m). Results indicated that although both younger and older adults altered their gait patterns under conditions of increased postural threat, the movement adaptations observed among older adults were substantially different to those adopted by younger adults. These age-dependent differences were strongly evidenced in the joint kinematics and the variability of the gait pattern within each condition. Our findings also indicated that when postural threat increased, the level of muscle activation throughout the gait cycle was altered in the distal musculature (gastrocnemius m. and tibialis anterior m.) among older adults only. Based on the age-related differences observed, we believe that the gait pattern alterations observed among younger and older adults reflect central set modifications to postural control that are mediated by a heightened anxiety imposed by the constraints of the testing conditions. Based on the age-dependent differences in the observed gait pattern modifications, it appears that the effects of anxiety on the control of locomotion are more pervasive for older adults than for younger adults.

Accidental Falls↗

The morphological basis of folded-wing posture in the American kestrel, Falco sparverius.

Gross dissection and histochemical analysis of the shoulder musculature of the American kestrel, Falco sparverius, revealed that four muscles are specialized for slow contraction and may function in the postural control of the folded wing. Mm. latissimus dorsi pars cranialis, scapulohumeralis cranialis, and brachialis were found to contain greater than 95% tonic fibers, whereas M. deltoideus minor was found to possess a relatively even mix of fast-twitch and tonic muscle fibers. M. latissimus dorsi pars cranialis, M. scapulohumeralis cranialis, and M. deltoideus minor all cross the shoulder joint caudally to the articulation, and M. brachialis crosses the elbow joint on the ventral surface of the forearm. This paper suggests postural muscles have largely been ignored in studies of avian musculature, and the need to consider a variety of possible muscle functions when analyzing locomotor muscle functions.

Animals↗

Postural interneurons in the abdominal nervous system of lobster. III. Pathways mediating intersegmental spread of excitation.

The multisegmented abdomen of crayfish and lobster assumes a variety of postures as components of different behavioral acts. Experimentally these postures can be maintained by activating any of a number of premotor positioning interneurons. The pathways by which the motor output in two or more segments is coordinated were here investigated for a small group of identified postural interneurons whose somata lie in the 2nd abdominal ganglion (A2). Stimulation of all postural interneurons examined evokes a motor output in other abdominal ganglia through which the axon of the neuron passes as well as in the ganglion of origin (ganglion containing the neuron's cell body). The spread of motor excitation away from the originating ganglion occurs via two general pathways. In the first pathway connections to postural motoneurons are made directly by processes of the postural interneuron which pass into ganglia distal to the originating ganglion. Examples of this are shown for two flexion producing interneurons (FPIs) 201 and 301. Each of these FPIs makes monosynaptic connections with motoneurons in A2 and with a homologous set of motoneurons in A3. All postural interneurons fired a set of corollary discharge interneurons (CDIs) whose activities were recorded from the abdominal connectives. Two FPIs, 202 and 301, and a third interneuron, 503, produced motor outputs in ganglia to which they did not project. The motor specificity established in A2 by stimulation of FPIs 202 and 301 (whose axons pass caudally) was preserved in more rostral ganglia, such as A1. Therefore, different sets of CDIs can be specifically recruited to spread the same motor program that is initiated in the originating ganglion to ganglia that do not receive projections from the stimulated postural interneuron. CDIs, in addition, have the capacity to elicit motor programs in distal ganglia that are markedly different from that expressed in the ganglion of origin. For example, although 503 produced an inhibitory output in the abdominal ganglia that it innervated (A1 and A2), a flexion response was generated by it in more caudal ganglia. The caudal flexion response was mediated in part through a monosynaptic activation of FPI 201 and through other unidentified CDIs. Thus, the interneuronal circuitry for postural control is composed of numerous components, some of which have regional control over different portions of the abdominal nerve cord. Depending upon the required movement, select components are coactivated, either serially or in parallel, to effect a variety of spatially distinct positions.

Abdomen↗

Changes in balance performance in physically active elderly people aged 73-80.

In our hospital in 1989 a series of 30 healthy elderly people participated in a study to evaluate the effect of physical training on improving balance. Thereafter, the majority of the people in this group continued with some kind of balance training. Seven years later we followed up 17 of the people who had participated in the original study. We wanted to evaluate the balance performance of these physically active elderly people (mean age 80.5 years) and compare it with their balance performance 7 years previously. Balance was found to be significantly impaired compared with 1989 in four out of six static balance tests. The time required to walk 30 m had increased significantly. The subjective ratings of vertigo and balance problems had not changed significantly, neither had the number of correct steps when walking forwards on one line and backwards between two lines. In dynamic posturography, the test with sway-referenced visual cues showed improved postural control, but no change in sway was seen in the other five sensory conditions. When sudden backward translations of the platform occurred, increased latencies of force response were seen.

Aged↗

Impaired lumbar movement perception in association with postural stability and motor- and somatosensory-evoked potentials in lumbar spinal stenosis.

STUDY DESIGN: A descriptive study of the associations between different neurophysiologic findings in patients with lumbar spinal stenosis. OBJECTIVES: To evaluate the ability to sense a change in lumbar position and the associations between lumbar movement perception, postural stability, and motor-evoked potentials and somatosensory-evoked potentials. SUMMARY OF BACKGROUND DATA: Patients with low back pain have impaired postural control and impaired lumbar proprioception. Altered motor-evoked potentials and somatosensory-evoked potentials have been often observed in lumbar spinal stenosis. METHODS: The study included 26 patients with clinically and radiologically diagnosed lumbar spinal stenosis. Their ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in the seated position. The abilities to indicate the movement direction and the movement magnitude were used as indexes of the ability to sense the lumbar rotatory movement. The postural stability was measured with a vertical force platform. The motor-evoked potentials were elicited by transcranial and lumbar stimulation and recorded from anterior tibialis muscles. The somatosensory-evoked potentials were elicited by transcutaneous electrical stimulation of the tibial nerve at the ankle. RESULTS: Twenty patients (76.9%; P = 0.006) reported the wrong movement direction. Furthermore, the patients consistently localized the movement sensation in their shoulders instead of the lumbar region. The altered motor-evoked potentials and somatosensory-evoked potentials were observed in 11 and 16 patients, respectively. Abnormal motor-evoked potentials had inconsistent associations with impaired movement perception and postural stability and abnormal somatosensory-evoked potentials had no associations with other findings. CONCLUSIONS: Many patients with lumbar spinal stenosis have difficulties in sensing the lumbar rotational movement, which may indicate impaired proprioceptive abilities. Abnormal motor-evoked potentials and somatosensory-evoked potentials are also frequent in lumbar spinal stenosis but do not necessarily occur in the same patients as the abnormal ability to sense trunk movement. These new findings add to our understanding of the pathophysiology of lumbar spinal stenosis.

Evoked Potentials, Motor↗

[Musculature as a source of back pain].

Lumbar muscle function is considered to be an important component of chronic low back pain (CLBP). Many studies have documented compromised muscle function in patients with CLBP. Although the mechanism associating muscle insufficiency to CLBP is not clearly understood, it is commonly held that the passive tissues of the spine are increasingly stressed with increasing functional muscle insuffiency. Functional instability of the spine plays a major role in the development of back pain. During the last few years, objective evaluation of the fatigue of back muscles by surface electromyography (EMG) with quantitative spectral techniques, evaluation of fibre type and size of the back muscles and quantifying of postural control of the lumbar spine during different tasks documented the failure of the spine in CLBP patients by a deficit of motor control more objectively. Besides this deficit, many patients show severe psychosocial problems and fear-avoidance beliefs. On this basis, treatment of CLBP with active rehabilitation, which includes educational, psychological, and social components along with the therapeutic exercises, has been increasingly advocated during recent years.

Back Pain↗

[The effect of visual feedback exercises on balance in normal subjects].

The effects of visual feedback exercises on balance was studied in normal individuals, to evaluate the efficacy of visual feedback of postural oscillation in improving stability. A DINAS-CAN dynamometric platform designed by the Valencian Institute of Biomechanics (IBv) was used. Before to commencing training sessions, we determined the following parameters in each individual: (a) static stability, via posturography; and (b) individual ability to displace and voluntarily maintain the center of gravity within the limits of stability. All static measures were poorer after training, but the differences were not significant (p > 0.01). In contrast, the exercises performed via visual feedback of postural control improved significantly (p < 0.01). Training by visual feedback facilitates integration of visual, somatosensory, and vestibular information. In normal individuals, stability improves under excentric conditions, but no improvement is seen in the central resting position.

Adult↗

Does horseback riding therapy or therapist-directed hippotherapy rehabilitate children with cerebral palsy?

Quantitative (not qualitative) studies were sought investigating whether horseback riding used as therapy improves gross motor function in children with cerebral palsy (CP). Eleven published studies on instructor-directed, recreational horseback riding therapy (HBRT) and licensed-therapist-directed hippotherapy were identified, reviewed, and summarized for research design, methodological quality, therapy regimen, internal/external validity, results, and authors'conclusions. Methodological quality was moderate to good for all studies; some studies were limited by small sample size or lack of non-riding controls. HBRT improved gross motor function in five of six studies (one study was inconclusive); hippotherapy improved gross motor function in all five studies. The studies found that during HBRT and hippotherapy: (1) the three-dimensional, reciprocal movement of the walking horse produced normalized pelvic movement in the rider, closely resembling pelvic movement during ambulation in individuals without disability; (2) the sensation of smooth, rhythmical movements made by the horse improved co-contraction, joint stability, and weight shift, as well as postural and equilibrium responses; and (3) that HBRT and hippotherapy improved dynamic postural stabilization, recovery from perturbations, and anticipatory and feedback postural control. The evidence suggests that HBRT and hippotherapy are individually efficacious, and are both medically indicated as therapy for gross motor rehabilitation in children with CP. Recommendations for future research are discussed.

Animals↗