Postural Control Deficits Research Articles

Effect of an Acute Bout of Soccer Heading on Postural Control and Self-Reported Concussion Symptoms

Our purpose was to determine if an acute bout of heading soccer balls adversely affected postural control and self-reported symptoms of cerebral concussion. Thirty-one college-aged soccer players were randomly placed into either a kicking group or a heading group. Subjects either kicked or headed 18 soccer balls over the course of 40 minutes. Subjects had their postural control assessed while standing on a force plate and completed a concussion symptoms checklist on three separate occasions: prior to, immediately following, and 24 hours after kicking or heading. There were no significant differences between the heading and kicking groups on the postural control measures prior to, immediately following, and 24 hours after kicking/heading. The heading group did, however, report significantly more concussion symptoms than the kicking group immediately after heading, but not 24 hours after heading. The number of previous concussions sustained by subjects did not influence the effects of heading. An acute bout of soccer heading appears to cause an increase in self-reported symptoms of cerebral concussion lasting less than 24 hours but no quantifiable deficits in postural control. Further research is needed to investigate the cumulative effects of soccer heading on postural control and other objective measures of brain function.

1208 Advanced, computerised cold cap for preventing chemotherapy induced alopecia

The purpose of this study was to determine how reduced plantar cutaneous sensation influences static postural control in individuals with and without CAI.A case-control study design.Twenty-six individuals with self-reported CAI and 26 matched healthy controls participated in this study. The plantar aspect of the participants’ foot was then submersed in ice water (0 °C) for 10 min to reduce plantar sensation. Before and after the cooling procedure, plantar cutaneous sensation thresholds and single leg balance with eyes open and closed were assessed.Significantly, higher scores were observed in both groups after ice water submersion (p < 0.001) indicating a significant reduction in the plantar cutaneous sensitivity after the cooling procedure. In single limb balance with eyes open, there were significant intervention main effects for the TTB ML mean (p < 0.001), TTB AP mean (p = 0.035) and TTB ML SD (p = 0.021); indicating postural control improvement in both groups post-cooling. In single limb balance with eyes closed, Group × Intervention interactions were observed for the TTB AP mean (p = 0.003) and TTB AP SD (p = 0.017); indicating postural control deficits in CAI group post-cooling, but no changes in the control group.The main finding of this study was that reduced plantar cutaneous sensation induced by an ice submersion procedure caused eyes closed postural control impairments in those with CAI but not healthy controls. The present investigation demonstrated that the ability to dynamically reweight among sensory inputs to maintain postural stability appears to be diminished in CAI patients compared to healthy controls.

Center-of-Pressure Parameters Used in the Assessment of Postural Control

Objective:To define the numerous center-of-pressure derivatives used in the assessment of postural control and discuss what value each might provide in the assessment of balance.Data Sources:MEDLINE and SPORTDiscus were searched with the termsbalance, postural control, postural sway,andcenter of pressure. The remaining citations were collected from references of similar papers. A total of 67 references were studied.Conclusions:Understanding what is represented by each parameter used to assess postural control is crucial. At the present time the literature has failed to demonstrate how the variables reflect changes made by the postural-control system. Until it can be shown that the center of pressure and its derivatives actually reveal changes in the postural-control system, the value of using these measures to assess deficits in postural control is minimized.

Postural balance in children with cerebral palsy.

Postural control deficits have been suggested to be a major component of gait disorders in cerebral palsy (CP). Standing balance was investigated in 23 ambulatory children and adolescents with spastic diplegic CP, ages 5 to 18 years, and compared with values of 92 children without disability, ages 5 to 18 years, while they stood on a force plate with eyes open or eyes closed. The measurements included center of pressure calculations of path length per second, average radial displacement, mean frequency of sway, and Brownian random motion measures of the short-term diffusion coefficient, and the long-term scaling exponent. In the majority of children with CP (14 of 23) all standing balance values were normal. However, approximately one-third of the children with CP (eight of 23) had abnormal values in at least two of the six center of pressure measures. Thus, mean values for path length, average radial displacement, and diffusion coefficient were higher for participants with CP compared with control individuals with eyes open and closed (p<0.05). Mean values for frequency of sway and the long-term scaling exponent were lower for participants with CP compared with control participants (p<0.05). Increased average radial displacement was the most common (nine of 23) postural control deficit. There was no increase in abnormal values with eyes closed compared with eyes open for participants with CP, indicating that most participants with CP had normal dependence on visual feedback to maintain balance. Identification of those children with impaired standing balance can delineate factors that contribute to the patient's gait disorder and help to guide treatment.

Postural balance in children with cerebral palsy

Postural control deficits have been suggested to be a major component of gait disorders in cerebral palsy (CP). Standing balance was investigated in 23 ambulatory children and adolescents with spastic diplegic CP, ages 5 to 18 years, and compared with values of 92 children without disability, ages 5 to 18 years, while they stood on a force plate with eyes open or eyes closed. The measurements included center of pressure calculations of path length per second, average radial displacement, mean frequency of sway, and Brownian random motion measures of the short‐term diffusion coefficient, and the long‐term scaling exponent. In the majority of children with CP (14 of 23) all standing balance values were normal. However, approximately one‐third of the children with CP (eight of 23) had abnormal values in at least two of the six center of pressure measures. Thus, mean values for path length, average radial displacement, and diffusion coefficient were higher for participants with CP compared with control individuals with eyes open and closed (p&lt;0.05). Mean values for frequency of sway and the long‐term scaling exponent were lower for participants with CP compared with control participants (p&lt;0.05). Increased average radial displacement was the most common (nine of 23) postural control deficit. There was no increase in abnormal values with eyes closed compared with eyes open for participants with CP, indicating that most participants with CP had normal dependence on visual feedback to maintain balance. Identification of those children with impaired standing balance can delineate factors that contribute to the patient's gait disorder and help to guide treatment.

Influence of two different sitting positions on postural adjustments in children with spastic diplegia.

The present study addressed the question whether the deviant postural adjustments in children with spastic diplegia can be attributed to their crouched sitting position or primarily to their neural deficit. Postural adjustments during sitting in an erect and in a crouched position on a movable platform were assessed in 10 children, aged 3 to 7 years 6 months, with mild-to-severe forms of spastic diplegia and 10 age- and sex-matched control children. Multiple surface EMGs of neck, trunk, and leg muscles and kinematics of head, body sway, and pelvis were recorded during forward and backward translations. The children with normal motor development showed a distinct adaptation of postural adjustments to sitting position. The children with cerebral palsy (CP) had a deficient adaptational capacity which was more pronounced in the erect than in the crouched position. Thus, the crouched sitting position did not induce postural deficiency but seemed to offer a solution to the sensory-motor problem of the instability experienced. Children with severe diplegia exhibited a lack of direction specificity in the leg muscles during backward body sway, which points to a basic deficit in postural control. In addition, these children showed marked dysfunctions in the precise tuning of the postural adjustments to task-specific conditions. In the children with mild-to-moderate forms of CP the basic level of control was intact.

Influence of two different sitting positions on postural adjustments in children with spastic diplegia

The present study addressed the question whether the deviant postural adjustments in children with spastic diplegia can be attributed to their crouched sitting position or primarily to their neural deficit. Postural adjustments during sitting in an erect and in a crouched position on a movable platform were assessed in 10 children, aged 3 to 7 years 6 months, with mild‐to‐severe forms of spastic diplegia and 10 age‐ and sex‐matched control children. Multiple surface EMGs of neck, trunk, and leg muscles and kinematics of head, body sway, and pelvis were recorded during forward and backward translations. The children with normal motor development showed a distinct adaptation of postural adjustments to sitting position. The children with cerebral palsy (CP) had a deficient adaptational capacity which was more pronounced in the erect than in the crouched position. Thus, the crouched sitting position did not induce postural deficiency but seemed to offer a solution to the sensory‐motor problem of the instability experienced. Children with severe diplegia exhibited a lack of direction specificity in the leg muscles during backward body sway, which points to a basic deficit in postural control. In addition, these children showed marked dysfunctions in the precise tuning of the postural adjustments to task‐specific conditions. In the children with mild‐to‐moderate forms of CP the basic level of control was intact.

Postural control of trunk during unstable sitting

A method for quantifying postural control of the lumbar spine during unstable sitting was developed. The unstable seat apparatus was equipped with leg and foot supports to isolate the control of the lumbar spine and trunk from the adjustments in the lower body joints. Polyester resin hemispheres with decreasing diameters were attached to the bottom of the seat to achieve increasing levels of task difficulty. The seat was placed on a force plate at the edge of a table and the participating subjects were instructed to maintain their balance while sitting on the seat. Coordinates of center of pressure (CoP) were recorded and quantified with summary statistics and random walk analysis. The CoP movement increased significantly with increased seat instability (task difficulty) ( p<0.01). Stabilogram plots of the CoP movement revealed short and long-term regions consistent with the hypothesis that the two regions reflect open and closed-loop postural control mechanisms. Repeatability of the CoP parameters was excellent for the summary statistics and the short-term random walk coefficients (0.77< R<0.96). It was fair for the long-term diffusion coefficients (0.56< R<0.57) and poor for the long-term scaling exponents (0.14< R<0.40). Summary statistics of the CoP movement were positively correlated with body weight (0.69< R<0.73) and the T9 to L4/L5 distance (0.43< R<0.54) of the subjects. This method can be applied to study the deficits in postural control of the lumbar spine in low-back pain population.

Kinematic characterization of standing reach: comparison of younger vs. older subjects

Objective. To characterize typical spinal motions that occur during standing reach and to describe differences in spinal motions and center of pressure displacements during reach between younger and older healthy adults. Design. Exploratory, cross sectional investigation utilizing video motion and biomechanics force platform analysis. Background. Standing reach provides a means for assessing both arm function and balance control in the context of a common functional activity. The interaction between age-related declines in spinal mobility and the spinal motion occurring during reach is poorly understood. The characterization of spinal motions during task performance for healthy subjects of different age groups is an important first step for understanding the relationship between impairments and physical performance in disabled populations. Methods. Thirty-four subjects ages 20–36 and 33 subjects ages 60–76 participated. Video motion and force plate analysis were used to characterize spinal motion and center of pressure displacements during the functional reach test for younger and older subjects. Results. Spinal motion during standing reach was characterized by forward trunk flexion, lateral trunk flexion, thoracolumbar rotation, and lower body rotation. Younger and older subjects differed ( P=0.05) in the amount of forward trunk flexion and thoracolumbar rotation which occurred but not lower body rotation. Younger subjects displaced their center of pressure further forward ( P=0.0001) and through a greater percentage of their initial base of support ( P=0.0001) than older subjects. Conclusion. This study provides the first multiplanar characterization of spinal motion used during standing reach. Significant differences for a number of variables existed between younger and older subjects. Relevance The characterization of standing reach provides a basis from which clinicians can make decisions regarding their interventions for persons with postural control deficits identified during reaching activities.

Spatial zones for muscle coactivation and the control of postural stability

It is hypothesized that, depending on the motor task, the angular range of a joint may be subdivided into zones in which agonist and antagonist muscles are coactive, only one group of muscles is active or neither group is active. It is further hypothesized that central commands may change the size and location of these spatial zones. We investigated whether spatial zones are used by the nervous system and how they may be changed to provide postural stability of the elbow. We compared responses to sudden unloading of the elbow flexors in neurologically normal subjects with those in patients with postural control deficits due to unilateral hemispheric and/or subcortical lesions. By studying responses in patients, we sought to determine whether the specification of zones of agonist/antagonist muscle coactivation (“coactivation zones”) may be essential for postural stability. At an initial elbow angle (130°; full extension is 180°), flexors were pre-activated by compensating an initial load which was equal to approximately 30% of the subject's maximal isometric voluntary contraction effort. Subjects were instructed not to correct the arm displacement elicited by a sudden decrease in the load. Data from 10 trials were collected at each of 4–6 final load levels (separated by 1.5–2 Nm) in order to map out the relationship between torque and angle in each subject. The procedure was repeated from a more flexed initial position of the elbow (100°). EMG activity from two elbow flexors and two elbow extensors, as well as torque, velocity and joint position were recorded. Healthy control subjects and patients with mild clinical symptoms had coactivation zones or small silent zones around the final positions established after unloading. In these subjects, final positions of the limb were stable. Voluntary movement, i.e., transition of the limb from one initial position to another, was associated with a change in the location of the zone in articular space. The presence of large silent zones in patients with moderate or severe symptoms was correlated with postural instability and oscillations about the final position of the arm after unloading. The comparison of results from healthy and hemiparetic subjects implies that the central specification of the size and the location of a coactivation zone may be fundamental for the control of posture and movement.

The Balance System

Literature demonstrates a clear, positive relationship between balance and the ability to successfully participate in functional activities. The purpose of this paper is to review the current knowledge about balance and to discuss the integration of this information into occupational therapy intervention. The reflex-hierarchy model of postural control proposes that balance develops over time through the integration of reflexes, whereas the systems model describes the interaction of the motor and sensory strategies for balance and the environment. Changes in musculoskeletal abilities with ageing may result in postural control deficits and concomitant difficulty managing daily activities safely. Common intervention strategies related to balance include environmental modifications and education of the client and the family. Occupational therapists need increased knowledge about the function of the balance system under various environmental conditions and during an array of occupations in order to appropriately challenge the balance system during occupational therapy treatment.