Stance Stability Research Articles

METHODS EVALUATING UPPER ARM AND FOREARM MOVEMENT DURING A QUIET STANCE

The article focuses on designing methods for quantitative assessment of the postural stability in a quiet stance by measuring segments of the appendicular skeleton, namely upper and forearms by inertial measurement units (IMU). Although an array of quantitative analysis methods assessing data of postural stability in the quiet stance exist by measuring the head and trunk movement, these methods have not been used to date to assess the behaviour of appendicular skeleton segments, namely the upper limbs. The applicability of methods assessing arm movement during the quiet stance has been verified by comparing the values of healthy subjects performing various stance tasks. The tests determined the quantitative evaluation of acceleration measured on individual anatomical axes. The quantities included: the volume of a convex polyhedron (PV), the volume of confidence ellipsoid (EV) and average velocity (AV) obtained by plotting three accelerations against each other. The most important findings in this study concern significant differences of PV and AV between dominant and non-dominant upper extremities and significant differences of EV, PV and AV between the data measured with a subject's eyes closed and open. Higher values of indicators were in the non-dominant extremities when subjects were measured with closed eyes. Interestingly, statistically significant differences between dominant and non-dominant arm movements were documented in PV and AV cases. This is due to the PV calculation being more sensitive to random deviations, i.e. the range of measured data, since the polyhedron bounds all the measured data, as opposed to the method, where the ellipse bounds only 95% of the measured data. In the case of the AV method, it is due to higher sensitivity to movements corresponding with arm tremors; the AV calculation relates not only to the range of measured data but, above all, to the intensity of data changes in the segment measured in a particular space and time interval. These conclusions demonstrate that it is possible to apply the proposed methods in the assessment of arm movement during a quiet stance since the differences between individual stance tasks and the dominant and non-dominant arms in specific cases of quiet stance have been identified. These conclusions also indicate a potentially more extensive medical application of the proposed quantitative data evaluation obtained from IMU, for example, within the rehabilitation process of injured appendicular skeleton segments. The use of cheaper IMU methods in mobile phones or watches can be of significant benefit in measuring the segmental movement of the appendicular skeleton in quiet stance. The methods outlined in this paper have remarkable potential in the field of telemedicine.

Stabilometric objectification of pelvic instabilities discriminated against by the Unipodal Pelvic Stability Test (UPST)

Introduction The purpose of this study was to determine whether the UPST was objectived by stabilometric parameters in both bipodal and unipodal stations. Method Twenty-six women, 15 men, average age 34 ± 6.9 years, are divided into 2 groups by an expert practitioner according to the results of the UPST. They were then evaluated in bipodal stance on force platform (Medicapteurs©, Fusyo®, France) for 31.6 sec at 40 Hz, under 4 conditions: – open eyes; – closed eyes; – open eyes with foam and; – closed eyes with foam (Capitoner® 8sh 2 mm). Subjects were recorded in unipodal situation for 5 sec at 40 Hz on the left and right feet, eyes open and eyes closed. All registrations were randomized and volunteers with a dominant left foot (2) or a UPST dysfunction on the left were excluded (4). Data analysis was performed by two MANOVA for each experimental time. Results Subjects with bilateral instability to the UPST showed a significantly larger surface area of the Centre of Pressure in the bipodal situation with eyes closed (F (2.32) = 4.48; P = 0.02 (η2 = 0.22)) and in unipedal situation with eyes open, only on the left foot (F (2.32) = 5.7; P = 0.008 (η2 = 0.26)) compared to volunteers without pelvic instabilities. The subjects with right dysfunctions to the UPST showed no significant difference in stabilometric parameters compared to the control population. Conclusion Subjects with bilateral pelvic instability have poorer postural stability in both bipodal and unipedal stance while isolated right pelvic instability cannot be characterized by force platform exams.

Stumbling Reactions in Partial Gravity - Neuromechanics of Compensatory Postural Responses and Inter-Limb Coordination During Perturbation of Human Stance.

Spontaneous changes in gravity play a significant role in interplanetary space missions. To preserve the astronauts’ capability to execute mission-critical tasks and reduce the risk of injury in transit and on planetary surfaces, a comprehensive understanding of the neuromuscular control of postural responses after balance deterioration in hypo- or hyper-gravity conditions is essential. Therefore, this study aimed to evaluate the effect of acute gravitational variation on postural adjustments in response to perturbations. Gravitational changes were induced using parabolic flight. Postural set was manipulated by randomly providing unilateral left, bilateral or split perturbations which require balance corrections to restore postural stability. In six subjects, postural reactions were recorded after anterior and posterior surface perturbations for progressively increased gravitational conditions spanning from 0.25 to 1.75 g. Ankle and knee joint kinematics and electromyograms (EMG) of eight leg muscles were recorded prior (PRE) and after perturbation onset. Muscle activation onset latencies and amplitudes in the short-, medium-, and long-latency responses (SLR, MLR, LLR) were assessed. Results demonstrate an increased muscle activity (p < 0.05) and co-contraction in the lower extremities (p < 0.05) prior to perturbation in hypo- and hyper-gravity. After perturbation, reduced muscle onset latencies (p < 0.05) and increased muscle activations in the MLR and LLR (p < 0.05), concomitant with an increased co-contraction in the SLR, were manifested with a progressive rise in gravity. Ankle and knee joint deflections remained unaffected, whereas angular velocities increased (p < 0.05) with increasing gravitation. Effects were more pronounced in bi- compared to unilateral or split perturbations (p < 0.05). Neuro-mechanical adaptations to gravity were more distinct and muscle onset latencies were shorter in the displaced compared to the non-displaced leg. In conclusion, the timing and magnitude of postural reflexes involved in stabilization of bipedal stance are gravity-dependent. The approximately linear relationship between gravity and impulse-directed EMG amplitudes or muscle onset latencies after perturbation indicates that the central nervous system correctly predicts the level of gravity. Moreover, it accurately governs contractions in the antigravity musculature to counterbalance the gravitational pull and to regain upright posture after its disturbance. Importantly, unilateral perturbations evoked fast reflex responses in the synergistic muscles of the non-displaced contralateral leg suggesting a synchronized inter-limb coordination mediated by spinal circuitries.

Static Postural Balance in Modern Pentathletes: A Pilot Study.

Postural balance is a key element of shooting effectiveness, which determines the outcome of modern pentathlon competitions. The aim of the study is to examine the postural balance of 27 pentathletes (12 females and 15 males; mean age: 18.0 ± 1.8 years), and 26 physically active, untrained subjects (12 females and 14 males; mean age: 22.5 ± 1.4 years), and to investigate the impact of footwear on the stability of the shooting position in pentathletes. Methods: Static postural balance was examined during quiet stance in four test conditions (standing in footwear with eyes opened, standing in footwear with eyes closed, standing barefoot with eyes opened, and standing barefoot with eyes closed). During each postural balance measurement, the participant remained still on the platform, with their arms in front of their body. Postural balance in the shooting position was only evaluated in the group of pentathletes. The athlete was asked to assume a comfortable shooting position on the platform and to aim at the target. Standard pentathlon targets and pistols were used in the study. Measurements were carried out twice (barefoot and in footwear). Results: In all conditions, pentathletes achieved lower values of posturographic measures than in the control group. In non-visual conditions, measures describing the surface area of the centre of pressure decreased in pentathletes and increased in the control group. Both pentathletes and non-athletes were equally stable barefoot as in footwear. Footwear did not affect postural sway in the shooting position in pentathletes. Conclusions: Pentathletes were found to have significantly better stance stability and were less vision-dependent in postural balance than untrained subjects. Bearing in mind that the shooting position of pentathletes was as stable barefoot as in footwear, the main factors which were most likely responsible for minimising body oscillations in the pentathletes were their high level of concentration and conscious control of body alignment.

Does Minimalist Footwear Design Aid in Postural Stability and Fall Prevention in Ergonomics?

The purpose of the article is to identify if novel footwear design could aid in postural stability and fall prevention in workplace. Footwear design has been reported to aid the task of maintaining postural stability or balancing in an erect stance while minimizing risk of falls. Minimalistic footwear that has design features such as low mass, lower heel height, and thin midsole can positively influence postural stability. Minimalistic military footwear has been shown to lower incidences of falls with efficient muscular effort. Occupational footwear that abides by safety standards with minimalistic features can help maintain postural stability and reduce falls.

The effects of textured insoles on quiet standing balance in four stance types with and without vision

BackgroundWearing a textured shoe insole can decrease postural sway during static balance. Previous studies assessed bipedal and/or unipedal standing. In contrast, we aimed to investigate if textured insoles modulated postural sway during four stance types (bipedal, standard Romberg, tandem Romberg, and unipedal), with and without vision.MethodsThe repeated measures design involved 28 healthy young adults (13 females; mean age = 26.86 ± 6.6 yrs) performing quiet standing in the four stance types on a force platform, under two different insole conditions (textured insole; TI vs. smooth insole; SI), with eyes open and eyes closed. Postural sway was assessed via the range and standard deviation of the COP excursions in the anterior-posterior and medial-lateral sway, and overall mean velocity.ResultsThe main effect of insole type was statistically significant at the alpha p = 0.05 level (p = 0.045). Compared to smooth insoles, textured insoles reduced the standard deviation of anterior-posterior excursions (APSD). While simple main effect analyses revealed this was most pronounced during eyes closed bipedal standing, insole type did not provide a statistically significant interaction with either stance or vision in this measure, or any other. Postural sway showed statistically significant increases across both stance type (bipedal < standard Romberg < tandem Romberg < unipedal), and vision (eyes closed < eyes open), in almost all measures. Stance and vision did have a statistically significant interaction in each measure, reflecting greater postural disturbances with eyes closed when stance stability decreased.ConclusionsOverall, these results support textured insole use in healthy young adults to reduce postural sway measures. This is because APSD is an index of spatial variability, where a decrease is associated with improved balance and possibly translates to reduced falls risk. Placing a novel texture in the shoe presumably modulated somatosensory inputs. It is important to understand the underlying mechanisms by which textured insoles influence postural sway. As such, utilising a healthy adult group allows us to investigate possible mechanisms of textured insoles. Future research could investigate the potential underlying mechanisms of textured insole effects at a neuromuscular and cortical level, in healthy young adults.

Modulation of tendon tap reflex activation of soleus motor neurons with reduced stability tandem stance

Reduced stability while standing typically decreases the soleus muscle Hoffmann (H-) reflex amplitude, purportedly to prevent the Ia afferent signal from excessively activating spinal motor neurons during the unstable stance. H-reflex measures, however, by excluding the spindle do not reflect the actual effect of the Ia pathway (i.e. the combined effects of spindle sensitivity and Ia presynaptic inhibition) on motor neuron activation, as tendon tap reflex measures can. But the effect of stance stability on soleus muscle tendon tap reflex amplitude is largely unknown. This study examined 30 young adults (mean(s), 21(2) years) as they stood in a wide stable stance position and an unstable tandem stance with a reduced base of support. Standing body sway, the amplitude of the soleus muscle tendon tap reflex, background EMG and tap force were measured in both stances. A repeated measured design t-test was calculated for each variable. Most subjects (69%) decreased tendon tap reflex amplitude when in the tandem stance position (mean decrease 11.6%), compared to the wide stance (wide stance 0.248(0.124) mV, tandem stance 0.219(0.119) mV, p < 0.05, Cohen’s d = 0.24 small) with no significant differences in background soleus and tibialis anterior EMG, and tap force across the stances. There was no relationship between the modulation of the tendon tap reflex amplitude across the stances and standing body sway in the tandem stance. Results support the idea that for most subjects examined, during a less stable stance the Ia excitation of motor neurons is decreased, likely by presynaptic inhibition, thereby avoiding potential instability in the reflex loop or saturating the reflex pathway and possibly interfering with descending control of the involved spinal motor neurons.

An Evaluation of the Effect of Vision on Standing Stability in the Early Stage of Parkinson’s Disease

Background: Postural instability is a common disorder in Parkinson’s disease (PD). The aim of this study was to evaluate stance stability of the subjects at the early stage of PD with both linear and nonlinear approaches. Moreover, this study aimed to find the effect of visual control on quiet stance postural control in these patients. Method: Seventeen PD patients (Hoehn/Yahr scale: 1) and 17 healthy control subjects were instructed to maintain quiet postural stance in 2 conditions (opened eyes and closed eyes). Four linear (excursion, path length, velocity, root mean square) and 1 nonlinear (approximate entropy) center of pressure (COP) parameters were calculated. A 2 × 2 mixed ANOVA was used for the final analysis. Results: Although there was no difference between the stability of PD patients and healthy control subjects based on excursion of COP in both mediolateral (ML) and anteroposterior (AP) directions, other linear parameters (path length of COP sways, velocity of COP sways, and root mean square in both ML and AP planes) showed that PD patients were significantly unstable compared to normal subjects (p value < 0.05). Vision influenced the stability of both groups significantly. The interaction of vision and group was not significant based on linear and nonlinear stability parameters. Conclusion: Although patients in the early stage of PD seem to be unstable based on COP linear measures, their postural control system is still flexible to adapt to environmental perturbations in quiet stance and they are not more visually dependent than healthy subjects to control stability in this position.

Effects of backpack and double pack loads on postural stability

Measurement of postural stability is crucial for identifying predictors of performance, determining the efficacy of physical training and rehabilitation techniques and evaluating and preventing injuries, particularly for heavy load carriage in hikers, mountain search and rescue personnel and soldiers. This study investigated the effect of load distribution on postural stability in an upright stance using backpack and double pack loads under conflicting or impaired somatosensory, visual and vestibular conditions. The sensory organisation tests were conducted on 20 young adults before and after a 10-min level walking exercise. Young adults’ ability to use inputs from somatosensory and visual systems to maintain postural stability was significantly reduced following a 10-min walking exercise with a heavy backpack (30% of body weight), whereas no significant changes were observed for double pack carriage. Thus, the distribution of heavy loads to the front and back provides superior balance control compared with back-only loading. Practitioner summary: This study investigated the effects of heavy (30% of body weight) load distribution on postural stability after a 10-min walking exercise. Backpack carriage significantly reduced postural stability, whereas there was no significant effect under double pack loads. Distribution of heavy loads on the front-and-back is desirable for superior balance control.

Sports Therapy Interventions Following Total Hip Replacement.

Sport rehabilitation is a reimbursable intervention assisting reintegration and self-help. In this study, we measured the effects of sport rehabilitation on muscle strength around the hip joint at 1 year after surgery, as well as cardiopulmonary endurance performance and stability of stance, in patients who had undergone a first implantation of a total hip endoprosthesis (total hip replacement, THR) as a treatment for osteoarthritis of the hip. 160 patients were randomly allotted either to an intervention group with intensive sport rehabilitation for the first year or to a control group. At three time points (baseline, six and twelve months after surgery), measurements were made of muscular strength around the hip joint (with isokinetic dynamometry), stability of stance, and endurance performance. The primary endpoint was the change in strength of the hip extensors, abductors, flexors, and adductors at twelve months after surgery. With respect to the primary endpoint, the results were not significantly better in patients who had received sport rehabilitation than in those who had not. At one year, the patients in the intervention group had less pain as measured by the WOMAC pain score (p = 0.023), though the size of this effect was small (r = 0.27). Health-related quality of life was higher in the intervention group at six months, albeit with a small effect size (p = 0.036, r = 0.25); this was no longer demonstrable at one year. The other parameters studied displayed no significant changes. This trial did not demonstrate any significant benefit of sports rehabilitation on functional outcomes in patients who had undergone total hip replacement. Nonetheless, positive trends after the intervention were seen in some parameters. The unexpectedly high dropout rate had been underestimated in the planning phase of the trial; further trials with larger numbers of patients should be performed.

The effects of total ankle arthroplasty on postural stability and loading symmetry in quiet stance

Ankle osteoarthritis is a debilitating condition affecting about 1% of the population with approximately 50,000 new instances annually. One treatment is total ankle arthroplasty (TAA), however, its effects on balance are not well understood. This study analyzed balance over a two-year period following TAA. 408 subjects (177 left, 231 right ankles) diagnosed with end-stage ankle osteoarthritis performed quiet standing trials while center of pressure (COP) data were collected. Data were compared across three time points (pre-op, 1-year, and 2-years post-op) and between surgical and non-surgical limbs using a linear mixed model with significance set at P = 0.05. COP excursions in the feet-together condition were not significantly different between limbs after 2 years in anteroposterior or mediolateral directions (P = 0.06, 0.08) after being significantly different between limbs in the anteroposterior (P = 0.014) and mediolateral direction (P < 0.001) pre-op. The vertical ground reaction force significantly decreased across time in the non-surgical limb, while reciprocally increasing in the surgical limb (P < 0.001). After 2 years, no significant difference in vertical ground reaction force between limbs existed (P = 0.20). Limb asymmetry indices decreased at each time point in both conditions (all P < 0.001) and were not significantly different from zero after 2 years in the feet-together condition (P = 0.290). In conclusion, surgical limb balance improved compared to pre-op, resulting in increased symmetry between limbs after 2 years. Vertical ground reaction forces on both limbs converge and limb asymmetry indices approach zero two years post-op. Differences in the COP excursion-loading symmetry relationship between limbs could be useful for identifying instability in other pathologies.

Evaluation of postural stability in overweight and obese middle-aged men

Background/aim: Weight gain is associated with balance disorders. This study intends to evaluate the postural stability in a natural stance in overweight and obese men by measuring the center of pressure (CoP) velocity in the medial-lateral (ML) and anteriorposterior (AP) directions. Materials and methods: A total number of 111 men categorized according to body mass index (BMI) into normal weight, overweight, and obese categories underwent a measurement of quiet standing with eyes open (EO) and with eyes closed (EC). Postural stability was assessed using a force platform. The average of CoP velocity was assessed in the two directions. Results: In the AP direction under EO and EC conditions, obese men swayed significantly quicker than men with normal weight. In the ML direction under EO and EC conditions, a higher velocity of CoP was seen in normal weight men than in obese men. Conclusion: The results propose a negative influence of obesity on postural stability in the AP direction. In the ML direction, obese men were more stable than normal weight men, probably caused by enlargement of the base of support in a natural stance.

Postural instability during attacks of migraine without aura.

Migraine has long been associated with unsteadiness and dizziness but postural control has not been studied in the ictal state. Here, the stability of upright stance during migraine attacks was measured. Static balance was assessed prospectively in migraine patients (n=30) during quiet stance for 40s on a posturographic force platform. Recordings were performed both ictally and in the pain-free interval. Subjects were assessed under four different conditions yielding different visual and proprioceptive feedback environments. Both ictal and interictal data were compared with age-matched healthy controls (n=30). Postural instability increased significantly under all experimental conditions during migraine attacks. Whilst standing on a foam pad with eyes closed, median sway area was 353mm2 in control subjects, 318mm2 in migraineurs in the pain-free period and 618mm2 in the ictal state. However, Romberg and vestibular Romberg quotients were not altered during migraine attacks. Spectral analyses of postural sway also showed similar profiles in migraineurs and controls. The severity of headache was inversely correlated to Romberg quotients. The demonstrated pattern of balance disorder during migraine attacks suggests a transient cerebellar dysfunction. Our findings also indicate that intense headache induces a re-weighting of sensory processing toward less dependence on visual and proprioceptive information.

Balance in Blind Subjects: Cane and Fingertip Touch Induce Similar Extent and Promptness of Stance Stabilization.

Subjects with low vision often use a cane when standing and walking autonomously in everyday life. One aim of this study was to assess differences in the body stabilizing effect produced by the contact of the cane with the ground or by the fingertip touch of a firm surface. Another aim was to estimate the promptness of balance stabilization (or destabilization) on adding (or withdrawing) the haptic input from cane or fingertip. Twelve blind subjects and two subjects with severe visual impairment participated in two experimental protocols while maintaining the tandem Romberg posture on a force platform. In one protocol, subjects lowered the cane to a second platform on the ground and lifted it in sequence at their own pace. In the other protocol, they touched an instrumented pad with the index finger and withdrew the finger from the pad in sequence. In both protocols, subjects were asked to exert a force not granting mechanical stabilization. Under steady-state condition, the finger touch or the contact of the cane with the ground significantly reduced (to ∼78% and ∼86%, respectively) the amplitude of medio-lateral oscillation of the centre of foot pressure (CoP). Oscillation then increased when haptic information was removed. The delay to the change in body oscillation after the haptic shift was longer for addition than withdrawal of the haptic information (∼1.4 s and ∼0.7 s, respectively; p < 0.001), but was not different between the two haptic conditions (finger and cane). Similar stabilizing effects of input from cane on the ground and from fingertip touch, and similar latencies to integrate haptic cue from both sources, suggest that the process of integration of the input for balance control is initiated by the haptic stimulus at the interface cane-hand. Use of a tool is as helpful as the fingertip input, and does not produce different stabilization. Further, the latencies to haptic cue integration (from fingertip or cane) are similar to those previously found in a group of sighted subjects, suggesting that integration delays for automatic balance stabilization are not modified by visual impairment. Haptic input from a tool is easily exploited by the neural circuits subserving automatic balance stabilization in blind people, and its use should be enforced by sensory-enhancing devices and appropriate training.

Kinematic and kinetic benefits of implantable peroneal nerve stimulation in people with post-stroke drop foot using an ankle-foot orthosis.

Contralesional 'drop foot' after stroke is usually treated with an ankle-foot orthosis (AFO). However, AFOs may hamper ankle motion during stance. Peroneal functional electrical stimulation (FES) is an alternative treatment that provides active dorsiflexion and allows normal ankle motion. Despite this theoretical advantage of FES, the kinematic and kinetic differences between AFO and FES have been scarcely investigated. To test whether walking with implanted FES leads to improvements in stance stability, propulsion, and swing initiation compared to AFO. A 4-channel peroneal nerve stimulator (ActiGait®) was implanted in 22 chronic patients after stroke. Instrumented gait analyses were performed during comfortable walking up to 26 weeks (n = 10) or 52 weeks (n = 12) after FES-system activation. Kinematics of knee and ankle (stance and swing phase) and kinetics (stance phase) of gait were determined, besides spatiotemporal parameters. Finally, we determined whether differences between devices regarding late stance kine(ma)tics correlated with those regarding the swing phase. In mid-stance, knee stability improved as the peak knee extension velocity was lower with FES (β = 18.1°/s, p = 0.007), while peak ankle plantarflexion velocity (β = -29.2°/s, p = 0.006) and peak ankle plantarflexion power (β = -0.2 W/kg, p = 0.018) were higher with FES compared to AFO. With FES, the ground reaction force (GRF) vector at peak ankle power (i.e., 'propulsion') was oriented more anteriorly (β = -1.1°, p = 0.001). Similarly, the horizontal GRF (β = -0.8% body mass, p = 0.003) and gait speed (β = 0.03 m/s, p = 0.015) were higher. An increase in peak ankle plantarflexion velocity and a more forward oriented GRF angle during late stance were moderately associated with an increase in hip flexion velocity during initial swing (rs = 0.502, p = 0.029 and rs = 0.504, p = 0.028, respectively). This study substantiates the evidence that implantable peroneal FES as a treatment for post-stroke drop foot may be superior over AFO in terms of knee stability, ankle plantarflexion power, and propulsion.

Evaluation of the effects of sensorimotor exercise on physical and psychological parameters in breast cancer patients undergoing neurotoxic chemotherapy.

Breast cancer is the most common cancer disease of women in industrialized countries. Neurotoxic chemotherapy drugs are known to harm peripheral nerves and cause a chemotherapy-induced peripheral neuropathy (CIPN). CIPN is one of the most common adverse events associated with Paclitaxel chemotherapy and may remain present long after the termination of chemotherapy. Thus, it reduces the patients' quality of life (QoL) both during chemotherapy and onwards, and can impose a danger on breast cancer survivors due to an increased risk of falling and fall-related injuries. The aim of this randomized-controlled trial (RCT) (n = 36) (IG: intervention group, n = 17) (CG: control group, n = 19) was to determine whether sensorimotor exercises have a positive effect on physical and psychological parameters in breast cancer patients undergoing neurotoxic chemotherapy (Paclitaxel). As a result, we were able to show significant improvements in postural stability in monopedal stance [left leg 16.17 ± 3.67 vs. 21.55 ± 5.33 (p < 0.001) and right leg 15.14 ± 2.30 vs. 20.85 ± 5.05 (p < 0.001)] and in bipedal stance [T1 vs. T0, - 0.49 (IG) vs. + 1.14 (CG) p = 0.039]. These results in posturography correlate with the clinical presentation with intervention group patients scoring significantly better on the Fullerton Advanced Balance Scale [37.71 ± 2.73 vs. 34.47 ± 3.98 (p = 0.004)]. Moderate strength training successfully prevented a strength loss in the IG that was remarkable in the CG (- 1.60 vs. 0.60, p = 0.029). Concerning the psychological parameters assessed via EORTC- and MFI-questionnaires, no significant improvements were found. Future studies should focus on the correlation of clinical and posturometry findings and subjective QOL such as the long-term-development of CIPN.

Haptic-Based Perception-Empathy Biofeedback Enhances Postural Motor Learning During High-Cognitive Load Task in Healthy Older Adults.

Falls and fall-induced injuries are major global public health problems, and sensory input impairment in older adults results in significant limitations in feedback-type postural control. A haptic-based biofeedback (BF) system can be used for augmenting somatosensory input in older adults, and the application of this BF system can increase the objectivity of the feedback and encourage comparison with that provided by a trainer. Nevertheless, an optimal BF system that focuses on interpersonal feedback for balance training in older adults has not been proposed. Thus, we proposed a haptic-based perception-empathy BF system that provides information regarding the older adult's center-of-foot pressure pattern to the trainee and trainer for refining the motor learning effect. The first objective of this study was to examine the effect of this balance training regimen in healthy older adults performing a postural learning task. Second, this study aimed to determine whether BF training required high cognitive load to clarify its practicability in real-life settings. Twenty older adults were assigned to two groups: BF and control groups. Participants in both groups tried balance training in the single-leg stance while performing a cognitive task (i.e., serial subtraction task). Retention was tested 24 h later. Testing comprised balance performance measures (i.e., 95% confidence ellipse area and mean velocity of sway) and dual-task performance (number of responses and correct answers). Measurements of postural control using a force plate revealed that the stability of the single-leg stance was significantly lower in the BF group than in the control group during the balance task. The BF group retained the improvement in the 95% confidence ellipse area 24 h after the retention test. Results of dual-task performance during the balance task were not different between the two groups. These results confirmed the potential benefit of the proposed balance training regimen in designing successful motor learning programs for preventing falls in older adults.

Dynamic Postural Instability in Individuals with High Body Mass Index

Objective(s): To evaluate and compare static and dynamic balance between individuals with high body mass index (BMI) and normal BMI.Methods: This case-control study included 19 individuals with high BMI and 7 individuals with normal BMI. It was conducted at a regional level university setting. The center of pressure (COP) changes during double limb stance and single limb stance were obtained using a force plate (Brazil Do). The main COP outcome measures included total displacement, area of sway, amplitude, velocity, and mean power frequency changes in anteroposterior (AP) and mediolateral (ML) directions.Results: During single limb stance, there was a significant difference in COP amplitude (cm) (p=0.015) and velocity (cm/s) (p=0.012) between the 2 groups in the AP direction. However, there were no significant differences found in the ML direction for amplitude (cm) (p=0.155) or velocity (cm/s) (p=0.186). There was no significant difference in the COP outcome measure for double limb stability for both the eyes closed and eyes opened conditions.Conclusion: Individuals with high BMI have impaired dynamic balance control in the AP direction reflected through higher COP amplitude and velocity. They have preserved stability in the ML direction during single limb stance stability. The COP changes during the double limb stance are unimpaired, both with eyes opened and closed.

Investigating feasibility of use of an Android Smart Phone Application (MoveIt) as a clinical outcome measure

Purpose: Mobile accelerometry has been validated against gold-standard motion analysis and current low-cost, low-tech clinical (Physiological Profile Assessment) measures of stance stability (Patterson et al., 2014). This could offer a fast, portable, specific and feasible clinical Method to the PPA. This study assesses feasibility of use of ‘MoveIt’ for student physiotherapists (MoveIt: An android Smart Phone application with a standardised procedure to measure stance stability).

The influence of a user-adaptive prosthetic knee on planned gait termination.

The added value of user-adaptive prosthetic knees has been predominantly evaluated in level walking or ramp/stair negotiation. Previous studies indicate that the activity pattern of individuals with an amputation mainly consists of short periods of continuous walking, indicating that a high percentage of ambulatory activity involves gait termination. The potential added value of user-adaptive prosthetic knees in gait termination has not been studied yet. Ten individuals with an amputation were measured with their own non-microprocessor controlled prosthetic knee and with the Rheo Knee II (a user-adaptive prosthetic knee). Spatiotemporal, kinematic and kinetic variables were measured. We found that the Rheo Knee II had no effect on the studied outcome parameters when compared to the non-microprocessor controlled prosthetic knee. We also found that the intact leg was responsible for producing the deceleration forces irrespective whether the last step was made by the intact or prosthetic leg. In conclusion we found that the prosthetic leg is limited in producing deceleration forces. Although user-adaptive prosthetic knees claim to increase stance stability, the added value of the Rheo Knee II on the studied outcome parameters is limited.