SEARCH · PubMed Health

Results for “Postural control”

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 1,603 records · Page 89Linked to original sources

PubMed1979

Pressure recordings in patients with femoral fractures in cast-braces and suggestions for treatment.

Five patients with femoral-shaft fractures were treated by cast-brace application and early ambulation. As fracture healing progressed, pressures between the thigh and the cast were recorded with the patients lying still, contracting the quadriceps while lying down, and in four weight-bearing postures. Control results were gained by application of a second cast-brace to three of the patients when they had recovered completely. Resting pressures averaging sixteen millimeters of mercury were recorded under the whole cast. Much higher values were recorded under the proximal two-thirds of the cast, and these increased as healing proceeded. Removal of the hip hinge, thereby eliminating fixed abduction, reduced pressure recordings significantly.

Adolescent↗

PubMed1984

Relationship between the home environment and sensorimotor development of Down syndrome and nonretarded infants.

Thirteen Down syndrome and 19 nonretarded infants participated in a prospective, longitudinal study designed to investigate the effect of the home environment on sensorimotor development as assessed by infant tests and direct observation of behavior. The present paper is concerned with the age span from 6.5 to 24 months. The two groups did not differ on measures of the social environment obtained at 6.5 months but differed on such measures at 17 months. At 6.5 months, the amount of tactile stimulation, encouragement of postural control, and level of social stimulation were all related to concurrent test performance in both groups; characteristics of the inanimate environment were of longer-term predictive significance among the Down syndrome babies. At 17 months, mothers' referential speech was related to the developmental pattern from 6.5 to 24 months for the Down syndrome children. The Down syndrome children tended to explore objects as a solitary activity, whereas exploration was done within the interactional situation by the nonretarded subjects. An attempt at multiple prediction demonstrated the usefulness of an interactional approach, showing the joint predictive value of language behavior and mothers' referential speech. Of special concern was how slowness of development among Down syndrome children may be a factor producing changes in maternal behavior.

Adolescent↗

PubMed1984

Functional capacity of men born in 1906-10, 1926-30 and 1946-50. A basic report.

This interdisciplinary study aims at describing the functional capacity of men belonging to different generation cohorts. The development of methods for the assessment of functional capacity is also the purpose of the study. Functional capacity is defined as a hierarchy comprising physical, mental and social areas into which individuals can be placed depending on the levels of the assessed functions. The study also aims at analyzing environmental and individual factors which are assumed to cause variation in the levels of functions. The purpose of this first report is to describe the framework of the study, the methods and main results concerning differences between cohorts and occupational groups. The sampling frame consisted of the population register of Jyväskylä town in January 1981. The basic populations were men in three age groups, born in 1946-50, 1926-30 and 1906-10. From each age group a systematic random sample of 250 men was made. Persons who had moved or died by the end of August 1981 or were living in institutions (6 men) were removed from the samples. The sample sizes were further randomly reduced so that the final samples consisted of 183, 188 and 176 men. At the time of the study the ages of the cohorts were 31-35, 51-55 and 71-75. The study included postal questionnaires, interviews and laboratory examinations. The basic questionnaire dealt with the background information, living conditions, life history, occupational history, social contracts and social participation, close human relations, use of time, health status and living habits. The second postal questionnaire dealing with psychic capacity included the following main items: life changes, self-realisation, personal trait anxiety, social fears, coping, self-respect, and the purpose of life. The basic questionnaire was checked in an interview when the subjects came for the laboratory examinations. The entrance interview also included questions about the most important events of previous 24 hours. In addition the subjects filled in a questionnaire on situational anxiety. The laboratory examinations included the following tests: cognitive capacity (4 tests), audiometry, speech understanding, visual tests, vibration threshold, posture control, reaction and movement time, tapping rate, leg extension velocity, anthropometric measurements, skin measurements, bone mineral density, physiotherapist's examination, physician's examination, blood analyses, isometric strength of muscles (5 muscles), anaerobic power, aerobic power and anaerobic threshold.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1984

[Regressing median peduncular infarction].

A case of a medial and caudal infarction of the midbrain in a 56 years old woman is reported. The clinical syndrome included a rapidly recovering sleepiness, an ophthalmoplegia related to damage to the caudal part of the oculomotor nuclear complex, a slow extrapyramidal dysarthria and a severe ataxia. The latter was characterized by the prevalent involvement of posture control, resulting from an axial hypotonia and the lack of balance reflexes. The CT scan showed a low density area in the central part of the midbrain. Electrophysiological investigations were carried out to study the impairment of the sensory and auditory tracts in the brainstem. In spite of the gravity of initial signs, recovery was good and the patient led a normal life 8 months later.

Ataxia↗

PubMed1996

Reconstruction of the transverse carpal ligament to restore median nerve gliding. The rationale of a new technique for revision of recurrent median nerve neuropathy.

Two clinical and four surgical steps can be taken to return gliding and nutritional balance to the median nerve after revision surgery for a recurrent median nerve neuropathy: Step One (Clinical): An accurate diagnosis of the median nerve traction neuropathy. Consider brachial plexopathy and terminal neuropathies. Step Two (Surgical): Comprehensive exploration and meso-epineurolysis of the median nerve from the radial remnants of the divided TCL and fibrosed radial and ulnar bursae by resection of the bursae and flexor tenosynovectomy. Step Three (Surgical): Fasciotomy of the volar carpal ligament to lengthen the ulnar leaf of the TCL; permits visualization of the ulnar artery and neurolysis of the ulnar motor nerve. Step Four (Surgical): Mobilize the previously released radical leaf TCL and motor median nerve from the origin of the thenar muscles. Step Five (Surgical): Restore the inner gliding surface and strength of the flexor retinaculum of the hand and wrist by reconstruction of the TCL and the forearm antebrachial fascia. Step Six (Clinical): An immediate postoperative hand therapy program to restore gliding to the median nerve and flexor tendons. Protocols for upper extremity nerve gliding should be carried out under supervision at selected daily intervals. A prevailing brachial plexopathy requires positive supervised therapy for nerve gliding and posture control.

Carpal Tunnel Syndrome↗

PubMed1996

Tourette syndrome and complex partial epilepsy--a case report.

Controversy exists over the pathophysiology of Tourette syndrome (TS). The case reported is a 37-year-old unmarried man suffering from both TS and complex partial epilepsy (CPE). He began to have seizures at 2-3 months of age. The CPE featured dark vision, dizziness, followed by unresponsiveness, a blank stare, occasional loss of posture control, and occasional automatism consisting of going to the toilet to urinate. TS gradually began to develop when he was 3-4 years of age. The tics were characterized by stereotypic stuttering, vocalization, hiccups, grimacing, snorting, and jerky supination of both forearms. EEG sharp waves with phase reversal at the left frontotemporal region were present but they were not related to the tics. Magnetic resonance imaging revealed atrophy of the left temporal and frontal lobes, as well as absence of normal asymmetry of basal ganglia. This case supports the theory that TS is related to the left frontal lobe, limbic system, and basal ganglia, but contradicts the hypothesis that the tics are ictal events.

Adult↗

PubMed1995

Atonic phenomena and partial seizures. A reappraisal.

At least three types of ictal atomic phenomena can be seen in partial seizures. Focal atomic seizures are partial seizures with ictal paresis or paralysis of one or more body parts preceding or independent of any convulsive activity. A diagnosis may be difficult without simultaneous EEG recording supplemented by video monitoring or polygraphy. Epileptic negative myoclonus manifests as brief lapses in tone in one or more muscle groups that interferes with motor coordination and postural control. Drop attacks can also occur in partial seizures, as have been well documented in patients with temporal or frontal lobe epilepsy. Different mechanisms may underlie these three phenomena. Focal atonic seizures probably result from relatively circumscribed seizure activity in one or more cortical areas that contribute to the elaboration and execution of motor functions. Whether this represents inactivation or interference in motor integration, or activation of inhibitory system, remains unresolved. The pathophysiology of epileptic negative myoclonus, like that of its positive counterpart, is probably to be found at a more local level, possibly from transiently enhanced local inhibition in the motor cortex. Drop attacks in partial seizures may be close in mechanism to that also seen in generalized seizures, possibly related to ictal activation of descending inhibitory pathways in the brainstem.

Electromyography↗

PubMed1997

Estimation of the size and directional output of functional groups of interneurons underlying abdominal positioning behaviors in crayfish.

Quantitative studies were made of a large population of interneurons that controls postural flexion and extension of the crayfish abdomen. The number of interneurons needed to produce a motor program was estimated by stimulating a single abdominal positioning interneuron and recording interneuronal activity that was evoked from rostral and caudal connectives in an isolated abdominal nerve cord. We also examined the role that these functional groups have in producing a stronger motor output in either a rostral or caudal direction and thus specifying various abdominal geometrics. The average number of interneurons responding to stimulation of a single abdominal positioning interneuron was 32 (range: 3-50; n = 27). The average number of interneurons that decreased activity was 10 (range: 2-32). Of 653 activated interneurons from 20 preparations, approximately 43% fired between 2 and 5 Hz, 33% fired between 6 and 15 Hz, and 25% fired > 15 Hz. The size of a recruited group was usually but not always correlated with the strength of its motor response or with the direction of motor bias. Therefore, the contribution of a group may depend upon the number of active elements as well as synaptic efficacy.

Abdomen↗

PubMedDate not supplied

Neuroanatomic substrates for vestibulo-autonomic interactions.

Recent anatomical studies have identified a network of central neural circuits that appear to integrate vestibular and autonomic information. Like vestibulo-ocular and vestibulospinal circuits, these pathways appear to be under inhibitory modulation by distinct regions in the medial aspect of the cerebellar cortex. These central circuits have the potential to explain the known influence of vestibular stimulation on autonomic motor responses through descending effects on brain stem autonomic regions. In a more global context, the extensive convergence of vestibular and autonomic information in both vestibular and autonomic brain regions is consistent with the concept that vestibular and visceral information (for example, blood pooling and visceral proprioception) are used to form a central representation of gravitoinertial parameters during movements. This representation can influence neural circuitry involved in postural control, cardiovascular control, perception of the spatial vertical and emotional or affective responses.

Animals↗

PubMed1998

Projections from the accessory optic system and pretectum to the dorsolateral thalamus in the pigeon (Columbia livia): a study using both anteretrograde and retrograde tracers.

In birds, optic flow is analyzed by two retinal-recipient nuclei: the nucleus of the basal optic root (nBOR) of the accessory optic system (AOS), and the pretectal nucleus, lentiformis mesencephali (LM). Previous anatomical studies have shown that both of these nuclei have descending projections to structures involved in oculomotor, head movement, and postural control. In this report, using biotinylated dextran amine (BDA) and cholera toxin subunit B (CTB) for anterograde and retrograde labelling, respectively, we investigated projections from the nBOR and LM to the dorsal thalamus. After injections of BDA into the nBOR and LM, terminals were consistently found in the nucleus dorsolateralis anterior pars lateralis and pars medialis, and the nucleus dorsalis intermedius ventralis anterior of the thalamus. Some terminals were also found in the nucleus dorsolateralis anterior, nucleus dorsomedialis anterior pars magnocellularis, nucleus dorsolateralis posterior, nucleus superficialis parvocellularis, and the ventrointermediate area. Injections of CTB into the dorsal thalamus resulted in retrogradely labelled cells in the pretectal region, including LM. Numerous cells were also seen in the nBOR pars lateralis and pars dorsalis, but fewer were seen in the nBOR proper. We suggest that the AOS is providing input to a thalamotelencephalic system that may be involved in several functions including: (1) multi-sensory analysis of self-motion, (2) perception of self-motion, (3) perception of the three-dimensional layout of the environment, (4) distinguishing object-motion from self-motion, and (5) spatial cognition.

Animals↗

PubMed1998

[Improvement of QOL by advance in the management of respiratory disorders, dysphagia and upper gastrointestinal disorders in children with severe cerebral palsy].

In children with severe cerebral palsy, the daily use of naso-pharyngeal airway, daily chest physiotherapy and adequate posture control markedly improve respiratory disorders and their consequent complications. Non-invasive ventiratory support methods such as nasal IPPV and nasal CPAP can be also effective. Enteral feeding through a naso-jejunal catheter can successfully manage feeding difficulty due to gastroesophageal reflux when surgical treatment is difficult. Exact assessment of aspiration by adequately performed video-fluoroscopic swallowing examination leads to national management of dysphagia. Tube feeding by intermittent oro-gastric catheterization combined with oral feeding is useful way in many dysphagic children. Surgical treatment for prevention of aspiration markedly improves the general condition. These treatments and managements have markedly improved the QOL, of children with severe cerebral palsy in many aspects. Cooperation of pediatricians, parents, school teachers and other community staffs is necessary for appropriate daily management of medical problems of these children.

Adolescent↗

PubMed1998

Psychotropic drugs and the aging patient.

Patients older than age 65 currently compose 13% of the US population, yet they receive 35% of all prescribed medications. In older patients, the complications of psychotropic drugs alone constitute a highly significant health problem. Pharmacokinetic and pharmacodynamic differences secondary to age or illness require careful consideration. Accumulation of drug might result from declining cardiovascular or renal function, alteration of body composition, or genetic or acquired inhibition of drug metabolism. As patients age, there is a general reduction in homeostatic mechanisms such as postural control, orthostatic circulatory responses, and visceral muscle function that may result in adverse drug experiences. specific receptor and neurotransmitter changes associated with senescence include reductions in central cholinergic and dopaminergic activities that lead to greater sensitivity to medications acting on these systems. Clinical vigilance is particularly important when prescribing newly available antidepressants and antipsychotics, since typically these medications are not systematically evaluated in older subjects before their release.

Aging↗

PubMed1998

[Motion analysis in whiplash injuries].

Motion analysis of the cervical spine is a sensitive tool in the fields of preventive and clinical biomechanics of whiplash. In the field of preventive biomechanics motion analysis contributes to validation and optimisation of dummy based crash test experiments and simulations. In the clinical field motion analysis up to now is of restricted value. Data exist about restrictions and pathologies of movement and motion of the cervical spine, coordinative disturbances, postural control, TMJ-function and oculomotor disturbances after whiplash. The standardisation of technical and clinical set-ups is necessary to establish a well proven biomechanical model of whiplash and whiplash related biomechanical dysfunction. Without this model the value of motion analysis for clinical use will be restricted due to lack of comparable data on sensitivity and specificity although motion analysis of the cervical spine is neither cost- nor time consuming and free of adverse effects. Within a prospective series of 28 patients (14 m/14 f) with a follow-up to six weeks we were lucky to describe numerically two different types of reaction to low energy (delta v < 20 km/h) rear end collision: Type I with disturbances in complex movements only, Type II with overall restriction of movement. Control of angular velocity during cyclic movements of the head was disturbed by oscillations of higher frequency in all patients. Recovery from whiplash within 6 weeks could be monitored.

Head↗

PubMed2006

Threshold control of arm posture and movement adaptation to load.

We addressed the fundamental questions of which variables underlie the control of arm movement and how they are stored in motor memory, reproduced and modified in the process of adaptation to changing load conditions. Such variables are defined differently in two major theories of motor control (internal models and threshold control). To resolve the controversy, these theories were tested (experiment 1) based on their ability to explain why active movement away from a stable posture is not opposed by stabilizing mechanisms (the posture-movement problem). The internal model theory suggests that the system counteracts the opposing forces by increasing the muscle activity in proportion to the distance from the initial posture (position-dependent EMG control). In contrast, threshold control fully excludes these opposing forces by shifting muscle activation thresholds and thus resetting the stabilizing mechanisms to a new posture. Subjects were sitting, holding the vertical handle of a double-joint manipulandum with their right hand and were facing a computer screen on which the handle and target to be reached were displayed. In response to an auditory signal, subjects quickly moved the handle from an initial position to one of two (frontal and sagittal) targets. No load was applied during the movement but in separate trials, a brief perturbation was applied to the handle by torque motors controlling the manipulandum. Perturbations were applied prior to or 3 s after movement offset, in the latter case in one of eight directions. The EMG activity of the majority of the seven recorded muscles was at zero level before movement onset and returned to zero level after movement offset. Those muscles that remained active before or after the movement could be made silent whereas previously silent muscles could be activated after a small passive displacement (several millimeters) elicited by perturbations in appropriate directions. Results showed that the activation thresholds of motoneurons of arm muscles were reset from the initial to a final position and that EMG activity was not position-dependent. These results were inconsistent with the internal model theory but confirmed the threshold control theory. Then the ability of threshold control theory to explain rapid movement adaptation to a position-dependent load was investigated (experiment 2 and 3). Subjects produced fast movement to the frontal target with and without a position-dependent load applied to the handle. Trials were organized in blocks alternating between the load and no-load condition (20 blocks in total, with randomly chosen number of five to ten trials in each). Subjects were instructed "do not correct" in experiment 2 and "correct" movement errors during the trial in experiment 3. Five threshold arm configurations underlying the movement production and adaptation were identified. When instructed "do not correct", movement precision was fully restored on average after two trials. No significant improvement was observed as the experiment progressed despite the fact that the same load condition was repeated after one block of trials. Thus, in each block, the adaptation was made anew, implying that subjects relied on short-term memory and could not recall the threshold arm configurations they specified to accurately reach the same target in the same load condition in previous blocks. When instructed to "correct" within each trial, precision was restored faster, on average after one trial. Major aspects of the production and adaptation of arm movement (including the kinematics, movement errors, instruction-dependent behavior, and absence of position-related EMG activity) are explained in terms of threshold control.

Adaptation, Physiological↗

PubMed1999

Ankle and hip postural strategies defined by joint torques.

Previous studies have identified two discrete strategies for the control of posture in the sagittal plane based on EMG activations, body kinematics, and ground reaction forces. The ankle strategy was characterized by body sway resembling a single-segment-inverted pendulum and was elicited on flat support surfaces. In contrast, the hip strategy was characterized by body sway resembling a double-segment inverted pendulum divided at the hip and was elicited on short or compliant support surfaces. However, biomechanical optimization models have suggested that hip strategy should be observed in response to fast translations on a flat surface also, provided the feet are constrained to remain in contact with the floor and the knee is constrained to remain straight. The purpose of this study was to examine the experimental evidence for hip strategy in postural responses to backward translations of a flat support surface and to determine whether analyses of joint torques would provide evidence for two separate postural strategies. Normal subjects standing on a flat support surface were translated backward with a range of velocities from fast (55 cm/s) to slow (5 cm/s). EMG activations and joint kinematics showed pattern changes consistent with previous experimental descriptions of mixed hip and ankle strategy with increasing platform velocity. Joint torque analyses revealed the addition of a hip flexor torque to the ankle plantarflexor torque during fast translations. This finding indicates the addition of hip strategy to ankle strategy to produce a continuum of postural responses. Hip torque without accompanying ankle torque (pure hip strategy) was not observed. Although postural control strategies have previously been defined by how the body moves, we conclude that joint torques, which indicate how body movements are produced, are useful in defining postural control strategies. These results also illustrate how the biomechanics of the body can transform discrete control patterns into a continuum of postural corrections.

Adult↗

PubMed2004

A limited set of muscle synergies for force control during a postural task.

Recently developed computational techniques have been used to reduce muscle activation patterns of high complexity to a simple synergy organization and to bring new insights to the long-standing degrees of freedom problem in motor control. We used a nonnegative factorization approach to identify muscle synergies during postural responses in the cat and to examine the functional significance of such synergies for natural behaviors. We hypothesized that the simplification of neural control afforded by muscle synergies must be matched by a similar reduction in degrees of freedom at the biomechanical level. Electromyographic data were recorded from 8-15 hindlimb muscles of cats exposed to 16 directions of support surface translation. Results showed that as few as four synergies could account for >95% of the automatic postural response across all muscles and all directions. Each synergy was activated for a specific set of perturbation directions, and moreover, each was correlated with a unique vector of endpoint force under the limb. We suggest that, within the context of active balance control, postural synergies reflect a neural command signal that specifies endpoint force of a limb.

Animals↗

PubMed2006

Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls?

Postural control is no longer considered simply a summation of static reflexes but, rather, a complex skill based on the interaction of dynamic sensorimotor processes. The two main functional goals of postural behaviour are postural orientation and postural equilibrium. Postural orientation involves the active alignment of the trunk and head with respect to gravity, support surfaces, the visual surround and internal references. Sensory information from somatosensory, vestibular and visual systems is integrated, and the relative weights placed on each of these inputs are dependent on the goals of the movement task and the environmental context. Postural equilibrium involves the coordination of movement strategies to stabilise the centre of body mass during both self-initiated and externally triggered disturbances of stability. The specific response strategy selected depends not only on the characteristics of the external postural displacement but also on the individual's expectations, goals and prior experience. Anticipatory postural adjustments, prior to voluntary limb movement, serve to maintain postural stability by compensating for destabilising forces associated with moving a limb. The amount of cognitive processing required for postural control depends both on the complexity of the postural task and on the capability of the subject's postural control system. The control of posture involves many different underlying physiological systems that can be affected by pathology or sub-clinical constraints. Damage to any of the underlying systems will result in different, context-specific instabilities. The effective rehabilitation of balance to improve mobility and to prevent falls requires a better understanding of the multiple mechanisms underlying postural control.

Accidental Falls↗

PubMed2005

A randomised controlled trial of postural interventions for prevention of musculoskeletal symptoms among computer users.

AIMS: To examine the effect of two workstation and postural interventions on the incidence of musculoskeletal symptoms among computer users. METHODS: Randomised controlled trial of two distinct workstation and postural interventions (an alternate intervention and a conventional intervention) among 376 persons using computer keyboards for more than 15 hours per week. The incidence of neck/shoulder symptoms and hand/arm symptoms during six months of follow up among individuals in the intervention groups was compared to the incidence in computer users who did not receive an intervention (comparison group). For individuals in the intervention groups, study staff adjusted workstations, where possible, and trained individuals to assume the intervention postures. Individuals reported musculoskeletal symptoms in a weekly diary. Participants who reported discomfort intensity of 6 or greater on a 0-10 visual analogue scale or who reported musculoskeletal symptoms requiring use of analgesic medication were considered symptomatic. RESULTS: There were no significant differences in the incidence of musculoskeletal symptoms among the three intervention groups. Twenty two (18.5%) participants in the alternate intervention group, 25 (20.2%) in the conventional intervention group, and 25 (21.7%) in the comparison group developed incident arm or hand symptoms. Thirty eight (33.3%) participants in the alternate intervention group, 36 (31.0%) in the conventional intervention group, and 33 (30.3%) in the comparison group developed incident neck or shoulder symptoms. Compliance with all components of the intervention was attained for only 25-38% of individuals, due mainly to the inflexibility of workstation configurations. CONCLUSIONS: This study provides evidence that two specific workplace postural interventions are unlikely to reduce the risk of upper extremity musculoskeletal symptoms among computer users.

Adolescent↗