The effect of voluntary arm abduction on balance recovery following multidirectional stance perturbations

The goal of this study was to investigate how voluntarily abducting one arm, 90° at onset of a rotational perturbation of the support surface, influences the recovery of upright stance. Young adults were tested under four stance conditions: abducting one arm to the horizontal only (AO); perturbation of stance using a support surface rotation only (PO); combined support surface rotation and abduction of the downhill arm, ipsilateral to tilt (IPS); and fourth abduction of the uphill, contralateral arm (CON). Simultaneous auditory and visual trigger cues were used for arm raising. Perturbations consisted of six directions of combined support surface roll and pitch rotation (7.5° and 60°/s). Outcome measures were whole body centre of mass (COM) movements and body segment angular displacements recorded with a motion analysis system, as well as leg, trunk, and arm EMG responses. Arm raises contralateral and ipsilateral to the direction of support surface roll were more rapid than in the AO condition and significantly reduced or increased, respectively, COM lateral displacements relative to the PO condition. The changes in COM displacements and velocities during combined CON arm raise and perturbation were greater than expected from the sum of displacements for AO and PO conditions alone, but less for the IPS condition. Arm raising increased trunk roll in a direction opposite arm raising was more than for the AO and PO conditions. Robust effects were also observed for hip abduction but not for leg flexion. Early balance correcting activity was enhanced on the side opposite arm raising and later stabilising activity reduced bilaterally in lower trunk muscles compared to summed activity for the AO and PO conditions. Similar effects were observed in gluteus medius muscles but effects were weak in ankle muscles. EMG onsets in muscles of the raised arm were earlier than in the AO conditions. We conclude that triggered arm abduction, contralateral to the direction of support surface rotation, had significant stabilization benefits for young adults and ipsilateral arm movements had destabilizing effects. The arm raises could be simultaneously executed with balance corrections. These results provide insights into the integration of balance corrections and voluntary commands into one automatic reaction that may be useful in training fall avoidanc

Maintaining the quality and relevance of industrial resource materials for technology education: the technology in context national support programme

A large number of companies are involved in the development and publication of resources for technology education. Whilst carrying information to teachers and pupils about technology in business and industrial context it is essential that the resources are of sound educational value and relate to the relevant attainment targets and programmes of study. This paper outlines a collaborative process for the development of a series of national curriculum technology resources with a number of different industrial sponsors. The clarification of process, content and the evolution of suitable pupil activities which can be resourced from the pack is discussed in terms of the industrial context and the programmes of study for Technology and EIU. From a number of potential start points the exemplar activities chosen offer strategies for progression and coherence in a number of different aspects of technology activity. The work of professional designers, architects and research and development engineers is seen in the context of investigating the needs of client and customer groups. Factors such as managing engineering and architectural projects to maximise energy efficiency and minimise environmental impact are discussed and illustrated. For example, interactive and managed technological systems are used in the context of travel and leisure to introduce pupils to data handling and a variety of automated and controlled systems for information display and baggage handling

Differences in coding provided by proprioceptive and vestibular sensory signals may contribute to lateral instability in vestibular loss subjects

One of the signatures of balance deficits observed in vestibular loss subjects is the greater instability in the roll compared to pitch planes. Directional differences in the timing and strengths of vestibular and proprioceptive sensory signals between roll and pitch may lead to a greater miscalculation of roll than pitch motion of the body in space when vestibular input is absent. For this reason, we compared the timing and amplitude of vestibular information, (observable in stimulus-induced head accelerations when subjects are tilted in different directions), with that of proprioceptive information caused by stimulus induced rotations of ankle and hip joints [observable as short latency (SL) stretch responses in leg and trunk muscle EMG activity]. We attempted to link the possible mode of sensory interaction with the deficits in balance control. Six subjects with bilaterally absent vestibular function and 12 age-matched controls were perturbed, while standing, in 8 directions of pitch and roll support surface rotation in random order. Body segment movements were recorded with a motion analysis system, head accelerations with accelerometers, and muscle activity with surface EMG. Information on stimulus pitch motion was available sequentially. Pitch movements of the support surface were best coded in amplitude by ankle rotation velocity, and by head vertical linear acceleration, which started at 13ms after the onset of ankle rotation. EMG SL reflex responses in soleus with onsets at 46ms provided a distal proprioceptive correlate to the pitch motion. Roll information on the stimulus was available simultaneously. Hip adduction and lumbo-sacral angular velocity were represented neurally as directionally specific short latency stretch and unloading reflexes in the bilateral gluteus medius muscles and paraspinal muscles with onsets at 28ms. Roll angular accelerations of the head coded roll amplitude and direction at the same time (31ms). Significant differences in amplitude coding between vestibular loss subjects and controls were only observed as a weaker coding between stimulus motion and head roll and head lateral linear accelerations. The absence of vestibular inputs in vestibular loss subjects led to characteristic larger trunk in motion in roll in the direction of tilt compared to pitch with respect to controls. This was preceded by less uphill flexion and no downhill extension of the legs in vestibular loss subjects. Downhill arm abduction responses were also greater. These results suggest that in man vestibular inputs provide critical information necessary for the appropriate modulation of roll balance-correcting responses in the form of stabilising knee and arm movements. The simultaneous arrival of roll sensory information in controls may indicate that proprioceptive and vestibular signals can only be interpreted correctly when both are present. Thus, roll proprioceptive information may be interpreted inaccurately in vestibular loss subjects, leading to an incorrect perception of body tilt and insufficient uphill knee flexion, especially as cervico-collic signals appear less reliable in these subjects as an alternative sensory inpu

Incapacitating hypersensitivity to one's own body sounds due to a dehiscence of bone overlying the superior semicircular canal. A case report

We present a case study of a 49-year-old patient with an 8-year history of hypersensitivity to sound produced by intrinsic but not extrinsic sources. Findings that indicated an organic problem were: a supranormal bone conduction threshold of −25 to −15dB HL from 0.25 to 1kHz with an air-bone gap of 15 to 45dB HL, a lower threshold and larger amplitude for vestibular-evoked myogenic potentials, eye movement reactions to sound and trunk pitch sway in response to sound. Results of immitance audiometry and otoacoustic emission testing were within normal limits and indicative of intact middle ear conductance. A high-resolution CT scan of the temporal bone demonstrated a dehiscence of bone overlying the superior semicircular canal. These findings support previous research indicating that auditory energy reaches the cochleo-vestibular receptor systems more easily via transmission through cerebrospinal fluid than through bone. Therefore, a dehiscence of the bone overlying the superior semicircular canal may lead to hypersensitivity to intrinsic sound. We recommend that similar findings in other patients be followed up with an evaluation of middle ear function and the temporal bone with high-resolution CT sca

Disparities in science literacy

Much is known about how adult science literacy varies internationally and over time, and about its association with attitudes and beliefs. However, less is known about disparities in science literacy across racial and ethnic groups. This is particularly surprising in light of substantial research on racial and ethnic disparities in related areas such as educational achievement, math and reading ability, representation in science, technology, engineering, and math (STEM) occupations, and health literacy. Given the importance of science literacy to securing and sustaining many jobs, to understanding key health concepts to enhance quality of life, and to increasing public engagement in societal decision-making, it is concerning if the distribution of science literacy is unequally stratified, particularly if this stratification reflects broader patterns of disadvantage and cultural dominance as experienced by minorities and educationally underserved populations. We describe here such disparities in science literacy in the United States and attempt to explain underlying drivers, concluding that the science literacy disadvantage among black and Hispanic adults relative to whites is only partially explained by measures of broader, foundational literacies and socioeconomic status (SES)

Magnet displacement: a rare complication following cochlear implantation

The purpose of this paper is to describe cases which reported complication after cochlear implantation in children: displacement of magnet from the receiver pocket, possibly aided by the use of magnetic toys. We observed magnet displacement in two female children from the same family and in one male child. Age at implantation was 23, 51, and 24months, respectively. Magnet displacement occurred at 37, 16, and 32months, respectively after the initial surgery. The magnets were replaced under general anaesthesia and we did not observe recurrent magnet dislodgement. Measurements indicated that forces required to remove the magnet from its pocket were not greater than those exerted by magnetic toys or the magnet used in the external sender coil. Although magnet displacement is not common after cochlear implantation, it is a major complication in children where subsequent general anaesthesia and surgery are necessary to replace the magnet. Therefore, we propose that pockets for removable magnets of cochlear implants used in children should be redesigned to increase forces to remove the magnet or that removable magnets not be used at al

Screening for balance disorders in mildly affected multiple sclerosis patients

Multiple sclerosis (MS) patients often complain about balance problems when Romberg's test and tandem gait are normal. The aim of the study was to determine if measures of trunk sway taken during a battery of stance and gait tasks could be used to detect subclinical balance disorders. We recorded trunk angular sway in the pitch and roll directions from 20 MS patients (EDSS 1.4±0.5) and 20 age- and gender-matched healthy controls (HCs), during 12 stance and gait tasks. We filmed 22 subjects simultaneously. Two neurologists assessed the videos, deciding whether task performance was pathological. Sway measures were significantly different between patients and HCs in eight out of 12 balance tasks. The most significant differences between MS patients and HCs were pitch angle range standing on one leg with eyes open on a firm surface (mean 3.13° vs. 2.09°, p=0.005), and on a foam support surface (mean 6.24° vs. 2.96°, p=0.006), pitch velocity range walking 8m with eyes closed (mean 75.5 vs. 50.2°/s, p<0.001) and pitch velocity range walking 3m on heels (mean 85.37 vs. 60.9°/s, p=0.002). Multivariate analysis revealed a model with three tasks which detected balance disorders in 84% of the MS patients and 90% of the HCs correctly. The neurologists achieved accuracies of 30% for the MS patients and 82% for the HCs. Using trunk sway measures during stance and gait tasks is a sensitive screening method for balance problems in MS patients, and is more accurate than assessment by trained neurologist

Benefits of short-term training with vibrotactile biofeedback of trunk sway on balance control in multiple sclerosis

Background and Aims: Patients with multiple sclerosis (MS) suffer from diminished balance control. We examined whether 4 sessions of training with vibrotactile biofeedback (VTfb) of trunk sway could improve their balance control and provide a carry-over effect. Methods: Baseline trunk sway was first measured for 15 MS patients. Then they received head mounted VTfb of trunk sway which was directionally active when trunk sway exceeded limits set using the baseline assessments. Stance and gait tasks were trained 2 times weekly for 2 weeks with VTfb. Assessments with VTfb were performed at the end of each week. Two weeks later balance was assessed without VTfb to determine if a carry-over effect was present. Results: Assessments with VTfb showed a significant decrease in trunk sway after 1 and 2 weeks of VTfb training (p<0.02). Carry-over improvements were also present (p<0.02). The greatest effects were found for tests of standing eyes closed stance on foam which resulted in a 59% decreased pitch sway angle (p=0.002) with VTfb and a 51% reduction (p=0.03) carry-over effect. Conclusions: This study indicates that balance control in MS patients improves rapidly after one week of training with VTfb and more slowly subsequently. The carry-over effect lasted at least 2 weeks. Future studies should determine, with more weeks of VTfb training, the time course of the slower balance and carry-over improvements following the first rapid improvement in balance control. We conclude that training with VTfb of trunk sway significantly improves balance control in MS patients, and could possibly reduce falls