Advancements in Functional Magnetic Resonance Imaging for Persistent Postural-Perceptual Dizziness

Persistent postural-perceptual dizziness, defined in 2017, is a chronic functional vestibular disorder. Which is characterized by persistent dizziness, unsteadiness, and/or non-spinning vertigo. However, the exact mechanisms remain unclear. In recent years, FMRI studies have provided key insights into the pathogenesis of PPPD. This review summarized functional imaging studies of persistent postural dizziness and its predecessors in recent years and found changes in the activity and functional connectivity of important areas of visual processing, multisensory vestibular and spatial cognition in patients with PPPD. In addition, factors such as stimulation mode, personality traits, mental comorbidities and external vestibular lesions have important effects on brain functional activities and connectivity patterns, and further stratified studies on these factors are needed in the future to further clarify and draw exact conclusions on the pathological mechanism of PPPD.

Nursing model of midwifery and postural and psychological interventions:Impact on maternal and fetal outcomes and negative emotions of primiparas

BACKGROUND Primiparas are usually at high risk of experiencing perinatal depression,which may cause prolonged labor,increased blood loss,and intensified pain,affecting maternal and fetal outcomes.Therefore,interventions are necessary to improve maternal and fetal outcomes and alleviate primiparas’negative emotions(NEs).AIM To discusses the impact of nursing responsibility in midwifery and postural and psychological interventions on maternal and fetal outcomes as well as primiparas’NEs.METHODS As participants,115 primiparas admitted to Quanzhou Maternity and Child Healthcare Hospital between May 2020 and May 2022 were selected.Among them,56 primiparas(control group,Con)were subjected to conventional midwifery and routine nursing.The remaining 59(research group,Res)were subjected to the nursing model of midwifery and postural and psychological interventions.Both groups were comparatively analyzed from the perspectives of delivery mode(cesarean,natural,or forceps-assisted),maternal and fetal outcomes(uterine inertia,postpartum hemorrhage,placental abruption,neonatal pulmonary injury,and neonatal asphyxia),NEs(Hamilton Anxiety/Depressionrating Scale,HAMA/HAMD),labor duration,and nursing satisfaction.RESULTS The Res exhibited a markedly higher natural delivery rate and nursing satisfaction than the Con.Additionally,the Res indicated a lower incidence of adverse events(e.g.,uterine inertia,postpartum hemorrhage,placental abruption,neonatal lung injury,and neonatal asphyxia)and shortened duration of various stages of labor.It also showed statistically lower post-interventional HAMA and HAMD scores than the Con and pre-interventional values.CONCLUSION The nursing model of midwifery and postural and psychological interventions increase the natural delivery rate and reduce the duration of each labor stage.These are also conducive to improving maternal and fetal outcomes and mitigating primiparas’NEs and thus deserve popularity in clinical practice.

The contribution of small and large sensory afferents to postural control in patients with peripheral neuropathy

Peripheral neuropathy(PN) is a multifarious disorder that is caused by damage to the peripheral nerves. Although the symptoms of PN vary with the etiology, most cases are characterized by impaired tactile and proprioceptive sensation that progresses in a distal to proximal manner. Balance also tends to deteriorate as the disorder becomes more severe, and those afflicted are substantially more likely to fall while walking compared with those who are healthy. Most patients with PN walk more cautiously and with greater stride variability than age-matched controls, but the majority of their falls occur when they must react to a perturbation such as a slippery or uneven surface. The purpose of this study was to first describe the role of somatosensory feedback in the control of posture and then discuss how that relationship is typically affected by the most common types of PN. A comprehensive review of the scientific literature was conducted using MEDLINE, and the relevant information was synthesized. The evidence indicates that the proprioceptive feedback that is conveyed primarily through larger type I afferents is important for postural control. However, the evidence indicates that the tactile feedback communicated through smaller type II afferents is particularly critical to the maintenance of balance. Many forms of PN often lead to chronic tactile desensitization in the soles of the feet and, although the central nervous system seems to adapt to this smaller type II afferent dysfunction by relying on more larger type I afferent reflex loops, the result is still decreased stability. We propose a model that is intended both to help explain the relationship between stability and the smaller type II afferent and the larger type I afferent feedback that may be impaired by PN and to assist in the development of pertinent rehabilitative interventions.

Adaptability of anticipatory postural adjustments associated with voluntary movement

The control of balance is crucial for efficiently performing most of our daily motor tasks, such as those involving goal-directed arm movements or whole body displacement. The purpose of this article is twofold. Firstly, it is to recall how balance can be maintained despite the different sources of postural perturbation arising during voluntary movement. The importance of the so-called "anticipatory postural adjustments"(APA), taken as a "line of defence" against the destabilizing effect induced by a predicted perturbation, is emphasized. Secondly, it is to report the results of recent studies that questioned the adaptability of APA to various constraints imposed on the postural system. The postural constraints envisaged here are classified into biomechanical(postural stability, superimposition of motor tasks),(neuro) physiological(fatigue), temporal(time pressure) and psychological(fear of falling, emotion). Overall, the results of these studies point out the capacity of the central nervous system(CNS) to adapt the spatio-temporal features of APA to each of theseconstraints. However, it seems that, depending on the constraint, the "priority" of the CNS was focused on postural stability maintenance, on body protection and/or on maintenance of focal movement performance.

Stiffness of Postural Alignment System Based on 3-Axis Actuators for Large Aircraft Components

Aircraft digital flexible assembly fixture and technologies are widely used in developed countries, while the traditional jig-based assembly mode is still used in China. The application study of aircraft digital flexible assembly system is just beginning in our country recently. To meet the requirements of automated posture alignment and join in digital assembly system for large aircraft components, a novel fitting fixture called 3-axis actuator is developed. On the basis of the actuators, three kinds of posture alignment system for large aircraft components are proposed, including the non-redundant system, the redundant actuating system, and the redundant leg system, and their constitutions and properties are introduced. Through deriving the feeding transmission stiffness model of single actuator and analyzing the inverse kinematics of these systems, the relationship between the external force and the changes of position and orientation of large aircraft component is obtained, and then the postural alignment stiffness models are established. With the method mentioned above, the postural alignment stiffness of three systems is computed by using the algebraic formulate, and the results show that redundant properties can increase system＇s postural alignment stiffness. As an example, a optimized layout of the assembly system for a given model of aircraft is developed, the results of application show that the layout has many advantages, such as high accuracy, stiffness, stability, reliability, efficiency and flexible, which can satisfy the requirement of aircraft digital assembly system well. The proposed study of postural alignment stiffness for different systems can supply the theoretic support for the optimization layout design of aircraft digital assembly system, and contribute to evaluate the system working performance of systems.

Diagnosis and management of postural orthostatic tachycardia syndrome：A brief review

Postural orthostatic tachycardia syndrome （POTS） has been recognized since at least 1940.A review of the literature identifies differences in the definition for this condition and wide variations in treatment and outcomes.This syndrome appears to describe a group of conditions with differing pathophysiology,which requires treatment tailored to the true underlying disorder.Patients need to be fully evaluated to guide treatment.Further research is required to effectively classify the range of underlying pathophysioiogy that can produce this syndrome and to guide optimal management.

Effect of suspension training on neuromuscular function, postural control, and knee kinematics in anterior cruciate ligament reconstruction patients

BACKGROUND Suspension training(SET)is a method of neuromuscular training that enables the body to carry out active training under unstable support through a suspension therapy system.However,there have been few reports in the literature on the application of SET to anterior cruciate ligament reconstruction(ACLR)patients.It is not clear what aspects of the patient's function are improved after SET.AIM To investigate the effect of SET on the neuromuscular function,postural control,and knee kinematics of patients after ACLR surgery.METHODS Forty participants were randomized to an SET group or a control group.The SET group subjects participated in a SET protocol over 6 wk.The control group subjects participated in a traditional training protocol over 6 wk.Isokinetic muscle strength of the quadriceps and hamstrings,static and dynamic posture stability test,and relative translation of the injured knee were assessed before and after training.RESULTS The relative peak torque of the quadriceps and hamstrings in both groups increased significantly(P<0.001),and the SET group increased by a higher percentage than those in the control group(quadriceps:P=0.004;hamstrings:P=0.011).After training,both groups showed significant improvements in static and dynamic posture stability(P<0.01),and the SET group had a greater change than the control group(P<0.05).No significant improvement on the relative translation of the injured knee was observed after training in either group(P>0.05).CONCLUSION Our findings show that SET promotes great responses in quadriceps and hamstring muscle strength and balance function in ACLR patients.

Exercise-induced muscle fatigue in the unaffected knee joint and its influence on postural control and lower limb kinematics in stroke patients

This study aimed to investigate the effects of exercise-induced muscle fatigue in the unaffected knee joint on postural control and kinematic changes in stroke patients. Forty participants（20 stroke patients, 20 age-matched healthy participants） were recruited. To induce fatigue, maximum voluntary isometric contractions were performed in the unaffected knee joint in a Leg Extension Rehab exercise machine using the pneumatic resistance. We measured static and dynamic balance and lower-limb kinematics during gait. Changes in postural control parameters anteroposterior sway speed and total center of pressure distance differed significantly between the stroke and control groups. In addition, changes in gait kinematic parameters knee and ankle angles of initial contact differed significantly between stroke（paretic and non-paretic） and control groups. Muscle fatigue in the unaffected knee and ankle impaired postural control and debilitates kinematic movement of ipsilateral and contralateral lower limbs, and may place the fatigued stroke patients at greater risk for falls.

Adding body load modifies the vibratory sensation of the foot sole and affects the postural control

Background: Heavy backpacks are often used by soldiers and firefighters. Weight carrying could reduce the speed and efficiency in task completion by altering the foot sole sensitivity and postural control.Methods: In fifteen healthy subjects, we measured the changes in sensitivity to vibrations applied to the foot sole when standing upright or walking after load carrying(30% body weight). The participants were asked to judge different vibration amplitudes applied on the 2 nd or 5 th metatarsal head and the heel at two frequencies(25 and 150 Hz) to determine the vibration threshold and the global perceptual representation(Ψ)of the vibration amplitude(Φ)given by the Stevens power function(Ψ=k×Φ~n). Any increase in negative k value indicated a reduction in sensitivity to the lowest loads. Pedobarographic measurements, with computation of the center of pressure(COP) and its deviations, were performed during weight carrying.Results: The 25-Hz vibration threshold significantly increased after weight carrying when standing upright or walking.After standing with the added loads, the absolute negative k value increased for the 25 Hz frequency. After walking with the added loads, the k coefficient increased for the two vibration frequencies. Weight carrying significantly increased both the CoP surface and CoP lateral deviation.Conclusions: Our data show that weight carrying reduces the sensory pathways from the foot sole and accentuates the center of pressure deviations.

Why Voluntary Postural Training Improves Recovery of Mental and Motor Functions in Patients with Traumatic Brain Injury?

There are data about the positive effect of rehabilitation with postural training in traumatic brain injury (TBI) patients. Brain mechanisms of functional recovery have been investigated insufficiently. In this study, functional recovery was examined in TBI patients with primary motor (20 patients) or higher mental impairment (10 patients)—post-traumatic Korsakov syndrome compared to healthy volunteers (n = 20). Integral clinical, stabilographic, and EEG approach was used as a tool for estimation of functional deficit in TBI patients before and after rehabilitation course. Specific alterations of stabilographic and EEG parameters were observed in TBI patients with primary motor or mental deficit before rehabilitation. Rehabilitation course with postural training improved recovery of all functions in both patient groups. To understand brain mechanisms of rehabilitation, we examined EEG findings during standing and postural task performance in healthy volunteers (n = 10). EEG coherence increase was marked for different spectral bands predominantly in the right hemisphere and more in alpha-2 and beta bands during postural task performance. These EEG findings were discussed in relation to rehabilitation effect on TBI patients and proved that postural training with visual feedback may provoke primary activation of the right hemisphere and can serve as a trigger for integration of cortical and subcortical structures and for recovery of motor and higher mental function in TBI patients.

Multiscale entropy:A tool for understanding the complexity of postural control

Clinical disorders often are characterized by a breakdown in dynamical processes that contribute to the control of upright standing.Disruption to a large number of physiological processes operating at different time scales can lead to alterations in postural center of pressure(Co P)fluctuations.Multiscale entropy(MSE) has been used to identify differences in fluctuations of postural Co P time series between groups with and without known physiological impairments at multiple time scales.The purpose of this paper is to:1) review basic elements and current developments in entropy techniques used to assess physiological complexity;and 2) identify how MSE can provide insights into the complexity of physiological systems operating at multiple time scales that underlie the control of posture.We review and synthesize evidence from the literature providing support for MSE as a valuable tool to evaluate the breakdown in the physiological processes that accompany changes due to aging and disease in postural control.This evidence emerges from observed lower MSE values in individuals with multiple sclerosis,idiopathic scoliosis,and in older individuals with sensory impairments.Finally,we suggest some future applications of MSE that will allow for further insight into how physiological deficits impact the complexity of postural fluctuations;this information may improve the development and evaluation of new therapeutic interventions.

Postural control deficits identify lingering post-concussion neurological deficits

Concussion,or mild traumatic brain injury,incidence rates have reached epidemic levels and impaired postural control is a cardinal symptom.The purpose of this review is to provide an overview of the linear and non-linear assessments of post-concussion postural control.The current acute evaluation for concussion utilizes the subjective balance error scoring system(BESS) to assess postural control.While the sensitivity of the overall test battery is high,the sensitivity of the BESS is unacceptably low and,with repeat administration,is unable to accurately identify recovery.Sophisticated measures of postural control,utilizing traditional linear assessments,have identified impairments in postural control well beyond BESS recovery.Both assessments of quiet stance and gait have identified lingering impairments for at least 1 month post-concussion.Recently,the application of non-linear metrics to concussion recovery have begun to receive limited attention with the most commonly utilized metric being approximate entropy(Ap En).Ap En,most commonly in the medial-lateral plane,has successfully identified impaired postural control in the acute post-concussion timeframe even when linear assessments of instrumented measures are equivalent to healthy pre-injury values;unfortunately these studies have not gone beyond the acute phase of recovery.One study has identified lingering deficits in postural control,utilizing Shannon and Renyi entropy metrics,which persist at least through clinical recovery and return to participation.Finally,limited evidence from two studies suggest that individuals with a previous history of a single concussion,even months or years prior,may display altered Ap En metrics.Overall,non-linear metrics provide a fertile area for future study to further the understanding of postural control impairments acutely post-concussion and address the current challenge of sensitive identification of recovery.

Athletes who train on unstable compared to stable surfaces exhibit unique postural control strategies in response to balance perturbations

Background:Athletes have been shown to exhibit better balance compared to non-athletes(NON).However,few studies have investigated how the surface on which athletes train affects the strategies adopted to maintain balance.Two distinct athlete groups who experience different types of sport-specific balance training are stable surface athletes(SSA) such as basketball players and those who train on unstable surfaces(USA) such as surfers.The purpose of this study was to investigate the effects of training surface on dynamic balance in athletes compared to NON.Methods:Eight NON,eight SSA,and eight USA performed five 20-s trials in each of five experimental conditions including a static condition and four dynamic conditions in which the support surface translated in the anteroposterior(AP) or mediolateral(ML) planes using positive or negative feedback paradigms.Approximate entropy(Ap En) and root mean square distance(RMS) of the center of pressure(Co P) were calculated for the AP and ML directions.Four 3 × 5(group × condition) repeated measures ANOVAs were used to determine significant effects of group and condition on variables of interest.Results:USA exhibited smaller Ap En values than SSA in the AP signals while no significant differences were observed in the ML Co P signals.Generally,the negative feedback conditions were associated with significantly greater RMS values than the positive feedback conditions.Conclusion:USA exhibit unique postural strategies compared to SSA.These unique strategies seemingly exhibit a direction-specific attribute and may be associated with divergent motor control strategies.

Reversible postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome(POTS) is a relatively rare syndrome recognised since 1940. It is a heterogenous condition with orthostatic intolerance due to dysautonomia and is characterised by rise in heart rate above 30 bpm from base line or to more than 120 bpm within 5-10 min of standing with or without change in blood pressure which returns to base line on resuming supine position. This condition present with various disabling symptoms such as light headedness, near syncope, fatigue, nausea, vomiting, tremor, palpitations and mental clouding, etc. However there are no identifiable signs on clinical examination and patients are often diagnosed to have anxiety disorder. The condition predominantly affects young female between the ages of 15-50 but is rarely described in older people. We describe an older patient who developed POTS which recovered over 12 mo. Recognising this condition is important as there are treatment options available to alleviate the disabling symptoms.

Right prefrontal cortex is activated for perceiving postural limits: a functional near-infrared spectroscopy study

The purpose of this study was to investigate neuronal mechanisms active during the percep-tion of forward postural limits in a standing po-sition and to specify fall-related brain activity using optical functional near-infrared spectros-copy. The study group included six right-handed, healthy female volunteers (range: 19, 20 years). The optical imaging device comprised 16 opto-des designed to provide 24-channel recording of changes in hemoglobin oxygenation. We meas-ured the changes of oxygenated hemoglobin levels in the frontal region when subjects per-ceived reachability in a standing position. Com- pared with those in other regions, the oxygen-ated hemoglobin levels in the right frontal region compatible with the right prefrontal cortex sig-nificantly increased. This result suggests that brain activities in the right prefrontal cortex are related to perception of reachability. Overesti-mation of postural limits has been reported as one of the risk factor for falling. This overesti-mation might be induced by dysfunction in the prefrontal cortex, resulting in a failure to inhibit a motor program that would have caused a loss of balance in reaching. Activation of the right prefrontal cortex may be a key factor for pre-venting accidental falls in the elderly and in pa-tients with neurological disorders.

Prevalence of Musculoskeletal Pain and Postural Deformity in Papad Making Women —A Cross-Sectional Observational Study

Aim and Objective: To study musculoskeletal problems like musculoskeletal pain, postural deformity and nerve radiculopathy in women engaged in Papad making by clinical assessment. Methodology: A cross-sectional observational survey carried out at Shri. Mahila Gruh Udyog Lijjat Papad, Nandanvan, Nagpur (2014). 50 female subjects were selected for the study. After taking permission from factory in-charge, the survey was conducted at the factory site and subjects were explained about the study in details in language they can understand. Consent form was obtained by subjects to participate. Data were collected by interview and clinical examination of women engaged in this occupation, As per proforma of musculoskeletal examination. Result: Almost 37 subjects out of 50 complaints about low back pain as a chief complaint followed by neck pain in 34, thoracic kyphosis was more profound postural deviation seen in 10 subjects. Paraspinal and calf muscle spasm is more common. Radiating pain and numbness more in dominant hand suggestive of involvement of median nerve were confirmed by Upper Limb Traction Test [ULTT]. Discussion: Socioeconomic status greatly influences the working needs of women. Shri. Mahila Gruh Udyog Lijjat Papad factory provides a platform for Women Empowerment. Faulty posture adoption for longer duration during work gives rise to various musculoskeletal problems. Conclusion: 74% of the study population has low back pain as a chief musculoskeletal problem. 34% present with postural deviation and 82% belong to poor socioeconomic scale.

Effect of Aging on Anticipatory Postural Adjustment and Reaction Times in the Pre-Crossing Phase of Obstacle Negotiation

Background: Obstacle crossing is the common reason of falling in older adults. Anticipatory postural adjustments phase (APAP) and reaction time phase (RTP) are two important factors in falling prediction. According to previous studies, these parameters increase in older adults at high risk falling. This study explored the effect of aging on APAP and RTP in obstacle negotiation. Method: Nineteen older adults (mean age: 66.73 ± 3.38 years) and twelve young adults (mean age: 26.5 ± 4.37 years), participated in this study. Participants take part in gait initiation task from a starting position on a force platform under two conditions, unobstructed and obstructed (obstacle placed at 1 m from the initial position). RTP and APAP were measured and Timed “Up” & “Go” test (TUG) as a functional test, recorded for all participants. Results: There was no significant difference between healthy young and older adults in RTP and APAP in the unobstructed and obstructed conditions. TUG test was the most sensitive indicator of falling between two groups. Conclusion: Information processing capacity for motor planning and proper strategy selection in pre crossing phase of obstacle negotiation did not have significant difference in healthy old and young groups. Maybe in respect to select healthy older adults without any neurological disorders and cognitive impairments, low attention demand of well learned walking and obstacle negotiation tasks, lead to perform both postural task more automatically and without any significant difference detection.

Analysis of Functional Capacity and Postural Balance in Former Cutters Cane

Background: Large-scale cane cultivation can promote health impacts of workers, resulting from weight bearing and repetitive movements. Musculoskeletal conditions can alter balance and increase risk of falls. Aim of Work: The objective of this study is to identify clinical characteristics and to correlate balance with functional capacity in ex-cane cutters. Methods: This was a descriptive exploratory study, 42 former workers of the cane cut, with mean age of 49 (±13) years, who were submitted to balance evaluation through the Berg Balance Scale (BSE) and the functional capacity was evaluated by the Incremental Shuttle Walk Test (ISWT). To investigate respiratory symptoms, the Medical Research Council questionnaire was used. Results: The individuals reached a mean of 52 points in BSE, considered low to moderate risk for falls and the average distance traveled of 446.2 (±188.5) meters, corresponding to 52.9% (±23.1) of the normal distance. Weak and negative correlations were found between changes in balance and exposure time (r2-0.16). Conclusion: It is concluded that excessive physical effort contributes to changes in the balance and, consequently, diminish functional capacity.

Adaptation of the Feedforward Postural Response to Repeated Continuous Postural Perturbations

We examined the adaptation of the postural response to repeated predictable platform oscillations. Our main goals were to determine whether the short-term changes that occurred during a minute long continuous postural perturbation trial were maintained in subsequent trials and to determine how many trials were required before participants fully adapted to the postural task. Ten participants performed ten minute-long postural trials on a platform that oscillated at 0.25 Hz before increasing to 0.50 Hz half way through each trial. Postural muscle onset latencies, burst amplitudes, and anterior posterior displacements of the center of pressure (COP) and center of mass (COM) were calculated for the last five cycles performed in each trial at 0.50 Hz. The postural strategy evolved in two phases: 1) immediate decrease in COP displacement;2) earlier activation of the postural muscles with smaller muscle burst amplitudes. After seven trials the postural response remained consistent.

The Effect of Giving Intervention 12 Balance Exercise on Postural Balance in Elderly

Elderly is an age group that has a high risk of experiencing health problems. One risk that can be experienced by the elderly is the risk of falling. One of the risk factors for falling in the elderly is decreasing in postural balance of the elderly. One of the non-pharmacological therapies developed to reduce the risk of falling in the elderly is to improve the ability of the elderly, especially in controlling postural balance. The purpose of this study was to determine the effectiveness of 12 balance exercises to improve postural balance in the elderly. This type of research is quasi experiments with static group comparison. The research data are obtained by researchers using observation sheet, then the data are tabulated. This study involved two research groups namely the control group (the group not given the intervention) and the treatment group (the group that was given the 12 balance exercise intervention). From the results of Paired samples, t-test with significance level α = 0.05 is obtained by the significance value (p) of 0.025. This study shows that the provision of 12 balance therapy exercise strategy is effective to improve postural balance in the elderly as a preventive effort from the risk of falling.