Postural Feedback Research Articles

Sensory feedback and central neuronal interactions in mouse locomotion.

Locomotion is a complex process involving specific interactions between the central neural controller and the mechanical components of the system. The basic rhythmic activity generated by locomotor circuits in the spinal cord defines rhythmic limb movements and their central coordination. The operation of these circuits is modulated by sensory feedback from the limbs providing information about the state of the limbs and the body. However, the specific role and contribution of central interactions and sensory feedback in the control of locomotor gait and posture remain poorly understood. We use biomechanical data on quadrupedal locomotion in mice and recent findings on the organization of neural interactions within the spinal locomotor circuitry to create and analyse a tractable mathematical model of mouse locomotion. The model includes a simplified mechanical model of the mouse body with four limbs and a central controller composed of four rhythm generators, each operating as a state machine controlling the state of one limb. Feedback signals characterize the load and extension of each limb as well as postural stability (balance). We systematically investigate and compare several model versions and compare their behaviour to existing experimental data on mouse locomotion. Our results highlight the specific roles of sensory feedback and some central propriospinal interactions between circuits controlling fore and hind limbs for speed-dependent gait expression. Our models suggest that postural imbalance feedback may be critically involved in the control of swing-to-stance transitions in each limb and the stabilization of walking direction.

POSTURAL CONTROL IMPAIRED IN MYOARTHROKINETIC AND NEURO-SENSORY DISORDERS

Interdependent subsystems involved in dynamic posture and locomotion are represented by osteoarticular, neuromuscular, sensory systems. Postural control is maintained by somato-sensory, visual vestibular feedback, integrated at the level of the locomotor system and the central nervous system. Postural stability is disturbed in mio-arthro-kinetic disorders. In proprioceptive loss, the automatic postural responses are diminished in amplitude and delayed in time; stretch reflexes in soleus and medial gastrocnemius are severely diminished; balance-correcting responses in tibialis anterior are diminished and delayed; backward motion of the trunk is reduced; movement strategies and synergies are disturbed. In peripheral vestibular loss, there are increased trunk responses to disruptive stimuli, with hypermetric trunk muscle responses and hypometric knee responses, but unchanged synergies; pathological changes to the modulation depth are produced; the amplitude of balance correcting responses in ankle muscles is severely reduced. Visual input serves to decrease the stiffness of the musculoskeletal system; it can be accomplished by decreasing the level of muscular activity across the joints of the lower limbs (in eyes-open subjects) or by reducing the gains of the other postural feedback mechanisms, the proprioceptive or vestibular systems (in eyes-closed subjects). Keywords: postural control, proprioceptive insufficiency, vestibular impairment.

Using skeletal position to estimate human error rates in telemanipulator operators.

In current telerobotics and telemanipulator applications, operators must perform a wide variety of tasks, often with a high risk associated with failure. A system designed to generate data-based behavioural estimations using observed operator features could be used to reduce risks in industrial teleoperation. This paper describes a non-invasive bio-mechanical feature capture method for teleoperators used to trial novel human-error rate estimators which, in future work, are intended to improve operational safety by providing behavioural and postural feedback to the operator. Operator monitoring studies were conducted in situ using the MASCOT teleoperation system at UKAEA RACE; the operators were given controlled tasks to complete during observation. Building upon existing works for vehicle-driver intention estimation and robotic surgery operator analysis, we used 3D point-cloud data capture using a commercially available depth camera to estimate an operator's skeletal pose. A total of 14 operators were observed and recorded for a total of approximately 8 h, each completing a baseline task and a task designed to induce detectable but safe collisions. Skeletal pose was estimated, collision statistics were recorded, and questionnaire-based psychological assessments were made, providing a database of qualitative and quantitative data. We then trialled data-driven analysis by using statistical and machine learning regression techniques (SVR) to estimate collision rates. We further perform and present an input variable sensitivity analysis for our selected features.

Postural control in emotional states: An effect of biofeedback

BackgroundEmotional states in the short term and affective impairments, such as anxiety and depression in the long run, can have a significant impact on postural control. Individuals with these conditions often struggle with maintaining balance during emotionally charged situations, which can increase their risk of falls and injuries. Biofeedback has been proposed as a potential intervention to improve postural control during emotional induction. Research questionHow do emotional stimuli affect postural control performance in the presence of real-time postural feedback? MethodsForty-two participants took part in the study. The visual stimuli used in the experiment to induce emotions of various valence in the subjects were video clips, containing a series of pictures (24 positive, 24 neutral and 24 negative pictures). During the experiment, participants were required to maintain balance standing on a force platform while watching the videos on a computer screen. For each subject, three sessions of 480 s were generated, each of which included two conditions: with and without biofeedback (a target on the screen indicating the subject’s position relative to the center of pressure (CoP). ResultsThe No Feedback condition provoked a higher medial-lateral and anterior-posterior sway, but lower velocity of CoP than the Feedback condition. We did not find any effect of the valence of emotional videos on indicators of postural control in No Feedback condition. However, both negative and positive videos provoked a lower velocity of CoP in comparison to neutral videos in the Feedback condition. SignificanceChanges observed in postural control during the Feedback condition in the presence of emotional stimuli (both negative and positive) could be explained by the shift in attention from the task of maintaining posture to the emotional videos. The results of this study have important implications for clinicians involved in postural training and rehabilitation.

Expansion of Body Adaptation Areas for Prism Adaptation Therapy Using Virtual Reality: Head Orientation Experiments on Normal Subjects

We developed a system to conduct posture‐measurable virtual prism adaptation therapy using an inside‐out tracking stand‐alone virtual reality system. This system enables the construction of a unilateral spatial neglect (USN) treatment room that is closed off from external stimuli from all surroundings in a hospital or home. Furthermore, it expands the prism adaptation body adaptive site, which was previously limited to the hand, to include the whole body using a symbolic body. This expansion allows for utilization of the new prism adaptation therapy in which giving postural feedback and the head is spontaneously turned to the neglected side. This prism adaptation is expected to improve the posture of patients with USN and turn the field of vision itself toward the neglected space. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Do open or closed postures boost creative performance? The effects of postural feedback on divergent and convergent thinking.

Can an individual’s body posture (expansive or contractive) affect their creative thinking (divergent or convergent)? Based on embodied cognition and the debate about the impact of nonverbal physical postures expressing power on psychological and behavioral outcomes, five experiments were conducted. We tested the prediction that expansive postures would have a positive effect on creativity tasks that have no right or wrong answer or optimal solution (divergent thinking), whereas contractive postures would have a positive effect on tasks with a right answer or an optimal solution (convergent thinking). As predicted, results revealed a positive effect of expansive postures on performance of creativity tasks requiring divergent thinking, such as producing original ideas (Study 1) or objects, either by combining shapes to create an original toy (Study 2) or by combining fragments to produce an original drawing (Study 3). Conversely, a positive effect of contractive postures was found on performance of insight tasks requiring convergent thinking, in which participants had to associate elements to discover a unifying and correct solution (Study 4) or overcome initial task constraints to find an optimal solution to a problem (Study 5). These findings open up new avenues for research in embodied creativity.

Sport-related back injury prevention with a wearable device

There has been a high incidence rates (∼41%) of back injury from undertaking weightlifting exercises as a result of improper lifting posture, where the spine should remain straight during a lifting movement which is often not adopted correctly by adolescent or beginner athletes. In this work we report a wearable device prototype consisting of independent sensor nodes using inertial measurement units to provide the user with real-time postural feedback on a companion application. From the data collected from four subjects, for several weight-lifting attempts, a strong correlation was found in the relative pitch angle between the upper cervical sensor and lower-lumbar sensor, which proved that the straightness of the user’s back could be inferred using only two sensor nodes.

Posture biofeedback increases cognitive load.

Attention may be important for actively maintaining posture during computer tasks, resulting in a dual-task tradeoff, where maintaining posture through extrinsic feedback imposes cognitive load. Mindfulness may make intrinsic postural feedback (which imposes less cognitive load) more available. Therefore, we hypothesized that the use of biofeedback would improve posture and negatively impact game performance; additionally, higher levels of mindfulness would be associated with lower game performance costs in the biofeedback condition. Healthy young adult participants played a challenging computer game for 10min with and without neck length biofeedback, in a counterbalanced repeated-measures design. For each condition, we assessed posture using neck shrinkage (percentage of best), and task performance (computer game score). Neck length was better retained and game performance was worse with biofeedback than without, consistent with the hypothesis that posture biofeedback imposed a cognitive load. In addition, participants with the most neck shrinkage suffered the greatest performance decrements from using biofeedback, and neck length retention during the task without biofeedback was associated with lower self-reported daily neck pain and higher self-reported mindfulness. Thus, those with the greatest need for postural feedback suffer the greatest performance decrements from extrinsic feedback. The results are consistent with the idea that mindfulness enables people to use intrinsic feedback to maintain posture without imposing a dual-task cost.

Does Postural Feedback Reduce Musculoskeletal Risk?: A Randomized Controlled Trial

Background: There is a high prevalence of musculoskeletal disorders among personnel working in the healthcare sector, mainly among nursing assistants and orderlies. Objective: The objective is to analyze the effectiveness of a multi-component intervention that included postural feedback in reducing musculoskeletal risk. Method: A total of 24 nursing assistants and orderlies in a hospital setting were randomly assigned to an intervention group or a control group. After collecting sociodemographic information, a selection of tasks was made and assessed using the REBA (rapid entire body assessment) method. A multi-component intervention was designed combining theoretical and practical training, including feedback on the postures performed by the professionals involved, especially those involving high musculoskeletal risk. This program was applied only to participants in the intervention group. Subsequently, eight months after the first assessment and intervention, the second assessment was carried out using the same method and process as in the first evaluation. Results: The results indicate that the musculoskeletal risk in the second assessment in the intervention group was significantly reduced. However, no significant changes were observed in the control group. Conclusion: The multi-component intervention applied can significantly reduce the musculoskeletal risk of nursing assistants and orderlies. In addition, it is a low-cost intervention with great applicability.

New Challenges Regarding the Intervention of Musculoskeletal Risk in Truck Service Garages

Background: The automotive industry is heavily affected by sick leaves caused by the handling of loads and using postures that produce musculoskeletal disorders. Research is needed to analyse their causes and find possible solutions to eliminate or mitigate these risks. Objective: Our objective was to analyse the level of musculoskeletal risk in the different work tasks performed by truck and bus mechanics. Our intention is also to analyse whether postural training and feedback can help reduce risk. Methods: The rapid entire body assessment (REBA) was used to assess the postures performed by 35 mechanics from eight branches throughout Spain. The participants were subsequently divided randomly into two groups (experimental group and control group). The experimental group (EG) was given training and feedback on their postures and the control group (CG) was not offered any type of intervention. A few months after the initial assessment, their postural load in the usual tasks was re-evaluated. Results: An overall average REBA Score: 10.49 ± 1.33. The main risk was found in the trunk and arms with sustained above-the-head postures. EG’s second results are significantly improved compared to the first (p = 0.026 *). Conclusions: These jobs have a high-risk level of musculoskeletal disorders. The course of action presented with postural training and feedback has shown satisfactory results. Nevertheless, given the size of the sample, further research will be needed to delve deeper into this possibility as a future line of intervention.

Use of a Wearable Posture-Correcting Device to Train Residents in Plastic Surgery: A Novel Approach to Surgical Ergonomics and Prevention of Associated Musculoskeletal Disorders.

Use of a Wearable Posture-Correcting Device to Train Residents in Plastic Surgery: A Novel Approach to Surgical Ergonomics and Prevention of Associated Musculoskeletal Disorders.

Effect of 6-Week Balance Exercise by Real-Time Postural Feedback System on Walking Ability for Patients with Chronic Stroke: A Pilot Single-Blind Randomized Controlled Trial.

Stroke causes balance dysfunction, leading to decreased physical activity and increased falls. Thus, effective balance exercises are needed to improve balance dysfunction. This single-blind, single-center randomized controlled trial evaluated the long-term and continuous effects of balance exercise using a real-time postural feedback system to improve balancing ability safely. Thirty participants were randomized into intervention (n = 15) and control (n = 15) groups; 11 in each group completed the final evaluation. The effect of the intervention was evaluated by muscle strength of knee extension, physical performance (short physical performance battery, the center of pressure trajectory length per second, and Timed Up and Go test [TUG]), and self-reported questionnaires (modified Gait Efficacy Scale [mGES] and the Fall Efficacy Scale) at pre (0 week), post (6-week), and at follow-up (10-week) visits. The TUG and mGES showed a significant interactive (group * time) effect (p = 0.007 and p = 0.038, respectively). The intervention group showed significant decreasing time to perform TUG from pre- to post-intervention (p = 0.015) and pre-intervention to follow-up (p = 0.016); mGES showed a significant change from pre-intervention to follow-up (p = 0.036). Thus, balance exercise using a real-time postural feedback system can confer a positive effect on the walking ability in patients with chronic stroke and increase their self-confidence in gait performance.

Staying UpRight in Parkinson’s disease: A pilot study of a novel wearable postural intervention

ObjectivesThis interventional pilot study aimed to 1) examine whether a novel wearable vibro-tactile feedback device (‘UpRight Go’) is effective and feasible to improve postural alignment in Parkinson’s disease (PD); 2) explore relationships between postural alignment and attention in PD; 3) explore effect of vibro-tactile device on balance and gait; and 4) gain initial feedback on the use of the vibro-tactile device in the laboratory and at home. Methods25 people with PD sat, stood and walked for two-minutes without and with the UpRight device attached to their upper backs to provide feedback on postural alignment in the laboratory. A sub-group (n = 12) wore the UpRight device at home for 60 min. per day for 7-days of postural feedback. Subjective feedback on use of the device was obtained in the laboratory and at the end of the 7-day period.The primary outcome for this study was posture measured by verticality of inertial measurement units (IMUs) at the neck, trunk and low back, which was done with and without the UpRight device. Secondary outcomes included clinical measures of posture, subjective feedback on the device, computerized attention measures, gait and balance. ResultsNeck postural alignment in PD was significantly improved (reduced neck flexion) with the UpRight during sitting and standing in both clinical measures (p = 0.005) and IMU outcomes (p = 0.046), but trunk and low back posture did not change. There was no change in postural alignment during walking with the UpRight. Postural alignment response was related to attentional capabilities. Many subjects (68 %) reported that they felt a benefit from the UpRight and most participants reported that the device was acceptable (Lab use; 72 %, Home use; 75 %). ConclusionThe UpRight Go feedback device may improve neck/upper-back posture in PD during sitting and standing, but not during walking. Postural alignment response to the device may depend on attentional mechanisms.

Exergaming Using Postural Feedback From Wearable Sensors and Exercise Therapy to Improve Postural Balance in People With Nonspecific Low Back Pain: Protocol for a Factorial Pilot Randomized Controlled Trial.

BackgroundPhysical exercise is a common treatment for people with low back pain (LBP). Wearable sensors that provide feedback on body movements and posture during exercise may enhance postural balance and motor control in people with LBP.ObjectiveThis study aims to investigate whether physical exercising with postural feedback (EPF) improves postural balance, motor control, and patient-reported outcomes in people with LBP.MethodsThe study was an assessor-blinded 2×2 factorial trial. We planned to recruit 80 participants with nonspecific LBP who did not receive treatment for LBP. In addition, we aimed to recruit 40 patients with chronic, nonspecific LBP who were receiving exercise therapy (ET) at the University Hospital Zurich. Both ET patients and participants without treatment were randomized to receive either an additional EPF intervention or no additional intervention. This resulted in four different combinations of interventions: ET+EPF, ET, EPF, and no intervention. The participants underwent outcome assessments at inclusion (T1); 3 weeks later, at randomization (T2); after an intervention period of 3 weeks with a predefined exercise schedule for participants receiving EPF (T3); and after an additional 6 weeks, during which participants assigned to the EPF groups could exercise as much as they wished (T4). Patients receiving ET completed their regularly prescribed therapies during the study period. Balance was assessed during quiet standing on a force platform, and motor control was assessed during a lifting task and a waiter’s bow task. Physical activity was recorded using an activity tracker and the participants’ mobile phones during the study. The predefined EPF schedule consisted of nine sessions of 20 minutes of exercise with a tablet and inertial measurement unit sensors at home. Participants performed a series of trunk and hip movements and received feedback on their movements in a gamified environment displayed on the tablet.ResultsThe first participant was recruited in May 2019. Data collection was completed in October 2020, with 3 patients and 32 eligible people without therapy who passed the eligibility check.ConclusionsAlthough it will not be possible to investigate differences in patients and people without other therapies, we expect this pilot study to provide insights into the potential of EPF to improve balance in people with LBP and adherence to such interventions.International Registered Report Identifier (IRRID)DERR1-10.2196/26982

Effects of Virtual Reality Based Rehabilitation Therapy with Postural Correction Feedback on Recovery of Upper Limb Function and non Use in Patients with Chronic Stroke

Effects of Virtual Reality Based Rehabilitation Therapy with Postural Correction Feedback on Recovery of Upper Limb Function and non Use in Patients with Chronic Stroke

Effectiveness of a lumbopelvic monitor and feedback device to change postural behaviour: the ELF cluster randomised controlled trial

ObjectivesThe aim of this clustered, randomised controlled trial was to assess the effectiveness of a lumbopelvic postural feedback device for changing postural behaviour in a group of healthcare workers. We...

Postural control during galvanic vestibular stimulation in patients with persistent perceptual-postural dizziness.

Over the past years galvanic vestibular stimulation (GVS) has been increasingly applied to stimulate the vestibular system in health and disease, but not in patients with persistent postural-perceptual dizziness (PPPD) yet. We functionally tested motion perception thresholds and postural responses to imperceptible noisy (nGVS) and perceptible bimastoidal GVS intensities in patients with PPPD with normal vestibulo-ocular reflexes. We hypothesized that GVS destabilizes PPPD patients under simple postural conditions stronger compared to healthy controls. They were compared to healthy subjects under several conditions each with the eyes open and closed: baseline with firm platform support, standing on foam and cognitive demand (count backward). Low and high GVS intensities (range 0.8-2.8mA) were applied according to the individual thresholds and compared with no GVS. PPPD patients showed a reduced perception threshold to GVS compared to healthy control subjects. Median postural sway speed increased with stimulus intensity and on eye closure, but there was no group difference, irrespective of the experimental condition. Romberg's ratio was consistently lower during nGVS than in all other conditions. Group-related dissociable effects were found with the eyes closed in (i) the baseline condition in which high GVS elicited higher postural sway of PPPD patients and (ii) in the foam condition, with better postural stability of PPPD patients during perceptible GVS. Group and condition differences of postural control were neither related to anxiety nor depression scores. GVS may be helpful to identify thresholds of vestibular perception and to modulate vestibulo-spinal reflexes in PPPD, with dissociable effects with respect to perceptible and imperceptible stimuli. The sway increase in the baseline of PPPD may be related to an earlier transition from open- to closed-loop mode of postural control. In contrast, the smaller sway of PPPD in the foam condition under visual deprivation is in line with the known balance improvement under more demanding postural challenges in PPPD. It is associated with a prolonged transition from open- to closed-loop postural feedback control. It could also reflect a shift of intersensory weighting with a smaller dependence on proprioceptive feedback control in PPPD patients under complex tasks. In summary, GVS discloses differences between simple and complex balance tasks in PPPD.

Sensor-based postural feedback is more effective than conventional feedback to improve lumbopelvic movement control in patients with chronic low back pain: a randomised controlled trial

BackgroundImproving movement control can be an important treatment goal for patients with chronic low back pain (CLBP). Although external feedback is essential when learning new movement skills, many aspects of feedback provision in patients with CLBP remain currently unexplored. New rehabilitation technologies, such as movement sensors, are able to provide reliable and accurate feedback. As such, they might be more effective than conventional feedback for improving movement control. The aims of this study were (1) to assess whether sensor-based feedback is more effective to improve lumbopelvic movement control compared to feedback from a mirror or no feedback in patients with chronic low back pain (CLBP), and (2) to evaluate whether patients with CLBP are equally capable of improving lumbopelvic movement control compared to healthy persons.MethodsFifty-four healthy participants and 54 patients with chronic non-specific LBP were recruited. Both participant groups were randomised into three subgroups. During a single exercise session, subgroups practised a lumbopelvic movement control task while receiving a different type of feedback, i.e. feedback from movement sensors, from a mirror or no feedback (=control group). Kinematic measurements of the lumbar spine and hip were obtained at baseline, during and immediately after the intervention to evaluate the improvements in movement control on the practised task (assessment of performance) and on a transfer task (assessment of motor learning).ResultsSensor-based feedback was more effective than feedback from a mirror (p < 0.0001) and no feedback (p < 0.0001) to improve lumbopelvic movement control performance (Sensor vs. Mirror estimated difference 9.9° (95% CI 6.1°-13.7°), Sensor vs. Control estimated difference 10.6° (95% CI 6.8°-14.3°)) and motor learning (Sensor vs. Mirror estimated difference 7.2° (95% CI 3.8°-10.6°), Sensor vs. Control estimated difference 6.9° (95% CI 3.5°-10.2°)). Patients with CLBP were equally capable of improving lumbopelvic movement control compared to healthy persons.ConclusionsSensor-based feedback is an effective means to improve lumbopelvic movement control in patients with CLBP. Future research should focus on the long-term retention effects of sensor-based feedback.Trial registrationclinicaltrials.gov NCT02773160, (retrospectively registered on May 16th, 2016).

Balance control systems in Parkinson's disease and the impact of pedunculopontine area stimulation.

Impaired balance is a major contributor to falls and diminished quality of life in Parkinson's disease, yet the pathophysiology is poorly understood. Here, we assessed if patients with Parkinson's disease and severe clinical balance impairment have deficits in the intermittent and continuous control systems proposed to maintain upright stance, and furthermore, whether such deficits are potentially reversible, with the experimental therapy of pedunculopontine nucleus deep brain stimulation. Two subject groups were assessed: (i) 13 patients with Parkinson's disease and severe clinical balance impairment, implanted with pedunculopontine nucleus deep brain stimulators; and (ii) 13 healthy control subjects. Patients were assessed in the OFF medication state and blinded to two conditions; off and on pedunculopontine nucleus stimulation. Postural sway data (deviations in centre of pressure) were collected during quiet stance using posturography. Intermittent control of sway was assessed by calculating the frequency of intermittent switching behaviour (discontinuities), derived using a wavelet-based transformation of the sway time series. Continuous control of sway was assessed with a proportional-integral-derivative (PID) controller model using ballistic reaction time as a measure of feedback delay. Clinical balance impairment was assessed using the 'pull test' to rate postural reflexes and by rating attempts to arise from sitting to standing. Patients with Parkinson's disease demonstrated reduced intermittent switching of postural sway compared with healthy controls. Patients also had abnormal feedback gains in postural sway according to the PID model. Pedunculopontine nucleus stimulation improved intermittent switching of postural sway, feedback gains in the PID model and clinical balance impairment. Clinical balance impairment correlated with intermittent switching of postural sway (rho = - 0.705, P < 0.001) and feedback gains in the PID model (rho = 0.619, P = 0.011). These results suggest that dysfunctional intermittent and continuous control systems may contribute to the pathophysiology of clinical balance impairment in Parkinson's disease. Clinical balance impairment and their related control system deficits are potentially reversible, as demonstrated by their improvement with pedunculopontine nucleus deep brain stimulation.

A Negative Effect of a Contractive Pose Is Not Evidence for the Positive Effect of an Expansive Pose: Commentary on Cuddy, Schultz, and Fosse (2018)

Cuddy, Schultz, and Fosse (2018) present p-curve analyses of the literature on postural feedback and conclude that their results are supportive of the inference that expansive poses (i.e., power poses) have positive effects on feelings of power and emotional/affective states. These inferences are incorrect because most of the examined studies cannot distinguish between the effects of an expansive pose and the effects of a contractive pose. Further, the few studies that can speak to these two effects suggest that an overall effect of posture is primarily due to the negative effects of a contractive pose (e.g., slouching) and not the positive effect of an expansive pose.