Impairments In Balance Control Research Articles

Towards an explanation for 'unexplained' dizziness in older people.

Subjective unsteadiness or dizziness, usually without increase in body sway, is common in older people. The absence of mechanistic understanding of such symptoms renders clinical management difficult. Here, we explore the mechanisms behind such idiopathic dizziness (ID), focusing on postural control abnormalities. Thirty patients with ID and 30 age-matched controls stood on a moving platform. Platform oscillations were randomly delivered at different velocities (from 0 to 0.2m/s). Markers of postural control, including objective sway (trunk sway path, recorded via a sensor attached to vertebrae C7), stepping responses, subjective instability and anxiety ratings were obtained. MRI scans were available for correlations with levels of cerebral small vessel disease in 28 patients and 24 controls. We observed a significant relationship between objective and subjective instability in all groups. The slope of this fit was significantly steeper for patients than controls, indicating greater perceived instability for the same body sway. Stepwise linear regression showed that the slopes of this objective-subjective instability relationship were best explained by concerns about falling (Falls Efficacy Scale-International), clinical physical functioning (Short Physical Performance Battery) and, to some degree, by neuroimaging markers of cerebral small vessel disease. In addition, patients had a reduced stepping threshold, suggesting an overly cautious postural response. The distorted perception of instability and subtle impairments in balance control, including abnormal and overly cautious stepping responses, underlies the emergence of ID. It appears to relate to changes in postural performance, psychological functioning and disruption of postural brain networks associated with cerebral small vessel disease.

A Passive Polycentric Mechanism to Improve Active Mediolateral Balance in Prosthetic Walking.

Prosthetic legs are typically passive systems without active ankle control, restricting mediolateral balancing to a hip strategy. Resulting balance control impairments for persons with a lower extremity amputation may be mitigated by increasing hip strategy effectiveness, in which relatively small hip moments of force are adequate for mediolateral balancing. To increase hip strategy effectiveness we have developed a prosthetic leg prototype based on the Peaucellier mechanism, the Sideways Balance Mechanism (SBM). This polycentric mechanism adds a frontal plane degree of freedom, reducing mediolateral body displacements. Adding a passive joint alone introduces instability, in which mediolateral body rotation leads to CoM height loss, ultimately resulting in a fall. The SBM however provides stability typically absent by lengthening under rotation, thereby compensating for CoM height loss. By allowing for both foot rotation (in-/eversion), and increased mediolateral ground reaction force the SBM increases hip strategy effectiveness. We aimed to provide proof of principle that the SBM can improve active mediolateral balance control in prosthetic walking by increasing hip strategy effectiveness compared to a typical set-up. Comparison between a typical set-up and the SBM showed an increased mediolateral ground reaction force at equal hip moments of force for a 2D forwards dynamics computer simulation, and a reduced hip moment of force at equal mediolateral ground reaction force for a case study. Results validate increased hip strategy effectiveness of the SBM compared to a typical set-up, providing proof of principle that adding an SBM to a prosthetic set-up improves mediolateral balance control in prosthetic walking.

Balance control impairments in Fabry disease.

BackgroundFabry disease (FD) is a rare inherited lysosomal storage disorder caused by the deficiency of the enzyme alpha-galactosidase A. This deficiency leads to an accumulation of glycosphingolipids leading to progressive and multisystemic disease, including renal, cardiac, and neurological damages. FD may also have neuro-otological and visual impairments, which can generate postural control alterations, inner ear, and vision being involved in this function. This study aimed to evaluate the impact of FD on postural control.MethodsIn total, fourteen adult patients (8 men/6 women, mean age = 37.6 ± 11.4 years) and two children (mean age = 11 years) with FD and 19 healthy adults (12 men/7 women, mean age = 36.5 ± 16.9 years) and two healthy children (mean age = 10.5 years) took part in this study. Postural control was evaluated by a sensory organization test combining three visual situations (eyes open, eyes closed, and sway referenced visual surround motion) with two platform situations (stable platform and sway referenced platform motion), aiming to calculate a composite equilibrium score (CES), a high score being representative of good postural control. Somatosensory (RSOM), visual (RVIS), and vestibular (RVEST) contributions to postural control were calculated, a low score reflecting a poor use of the indicated sensory input.ResultsThe CES was lower in adult patients with FD compared with the healthy subjects (p < 0.001). RVIS (p = 0.001) and RVEST (p = 0.003) were lower in patients with FD compared with the control group, whereas no difference in RSOM was observed.ConclusionInner ear and visual pathologies associated with the central nervous system impairments are factors of postural control impairments. Physical activities, which can also be rehabilitative, by maintaining or increasing the weight of proprioception, may help diminish dependency on altered sensorial inputs.

Balance Control in Patients with Subacute Non-Specific Low Back Pain, with and without Lumbar Instability: A Cross-Sectional Study.

BackgroundPatients with low back pain (LBP) have poorly coordinated neuromuscular control, which may alter the normal postural stability of the spine. Altered movement control may occur at any stage of LBP.Purpose(1) To identify differences in balance control and proprioceptive sense between subacute non-specific LBP (NSLBP) patients with and without lumbar instability (LI) and healthy subjects and (2) to investigate the correlation between factors of motor control deficits and balance.Patients and MethodsThirty-six participants matched by gender, age, and body mass index (BMI) were allocated into three groups of 12: subacute NSLBP patients with LI, subacute NSLBP patients without LI, and healthy subjects. Balance, proprioceptive sense, pain, functional disability, and fear of movement were evaluated.ResultsSubacute NSLBP patients with LI exhibited greater impairments in balance control, proprioceptive sense, and functional ability than patients without LI (p<0.05). Subacute NSLBP patients showed more impairments in balance control, proprioceptive sense, and fear of movement than healthy subjects (p<0.001), with the following effect sizes (partial η2) for static balance on stable and unstable surface: 0.597 and 0.560, anticipatory balance: 0.417, and dynamic balance: 0.536; proprioceptive sense: 0.676; and fear of movement: 0.379. Significant fair correlations were found between (1) static balance and proprioceptive sense, functional disability, and fear of movement; (2) functional reach test (FRT) and pain; and (3) the five times sit to stand test (FTSTS) and functional disability.ConclusionSubacute NSLBP patients with LI showed greater impairment in balance control than patients without LI. Reduced proprioceptive sense, increased pain, functional disability, and fear of movement were fairly related to impaired balance.

Modern aspects of the pathophysiology of walking disorders and their rehabilitation in post-stroke patients

The problem of rehabilitation of post-stroke patients with motor deficit remains relevant with growing prevalence of disability and decreasing mortality, despite all measures aimed at stroke prevention and morbidity reduction. One of the most common consequences of stroke is gait impairment as a result of spastic paresis of the lower limb (decreased gait velocity, shortened step, excessive loading of intact limb etc.), which leads to significant maladaptation, increased risk of falls, decrease in quality of life. The article presents a detailed review of motor action in normal and pathologic conditions, analysis of neuronal structures involved into a movement act in healthy individuals and in stroke patients, current aspects of gait pathophysiology, characteristics of post-stroke gait (speed and asymmetry of gain, balance control impairment). A separate paragraph is devoted to gait recovery after stroke with analysis of existing and developing strategies of rehabilitation, aimed at the improvement of vertical posture, balance control and movement, condition, tone and functioning of skeletal muscles. Authors also analyze new research information on the efficacy of botulinum toxin preparations and programs of Guided Self-Rehabilitation Contracts (GSC), present the results of clinical trials demonstrating the efficacy of combination of these two methods.

지면 경사도에 따른 후방 낙상 시 소뇌성 운동실조증 환자의 자세제어 특성 연구

The Cerebellar damage leads to falls due to the impairments in balance control, and secondary damage is a terrifying factor that may cause injuries. Concerning the fear of falls in patients with cerebellar disease (CD), this study examined the kinematic characteristics on body control abilities such as the movements of the upper and lower limbs and the motion of stepping to recover the balance when a back fall is occurred with increased ground inclination. Eight patients diagnosed with CD and 8 age-matched normal controls (NC) participated in the study. We evaluated the ability to recover the balance independently through stepping movements by causing the situation of a backward fall with the lean-and-release method and four different ground inclination conditions. The results demonstrated that there were no differences between two groups in overall stepping characteristics such as total steps, initiation time and step distance. However, the distance between the foot and body COM was shorter and velocity of COM movement at landing of first step was higher in CD than NC as the ground inclination increased. These findings indicate that patients with cerebellar disease used an inefficient movement strategy that does not help to recover their trunk motion from falling when fear of falling is elevated.

Dynamic balance in patients with degenerative lumbar spinal stenosis; a cross-sectional study

BackgroundDegenerative lumbar spinal stenosis (LSS) is a prevalent condition in adults over the age of 55 years. The condition is associated with activity limitations that are related to increased pain when engaging in weight-bearing activities, such as walking and standing, and release of pain while sitting down or bending forward. The limitation on ambulation is also associated with impaired balance although the types of balance problems are sparsely described in this patient group. The purpose of this study was to assess dynamic balance in persons with LSS by the Mini-BESTest and explore the associations with self-reported balance and functional disability.MethodsSixty two participants were included in this cross-sectional study. The main outcome measure was the Mini-BESTest, providing a total score and sub-scores for 4 balance control systems (Anticipatory Adjustment, Reactive Response, Sensory Orientation, Stability of Gait). The Swiss Spinal Stenosis Questionnaire provided sub-scores for self-reported balance problems and walking function (FUNC).ResultsThe participants showed large inter-individual variation in all measures of balance. The Mini-BESTest score ranged from very good to poor and the mean value was 22.8 (SD 3.5). Nineteen participants (31%) reported having frequent balance problems. Logistic regression analyses showed that both the total Mini-BESTest score (OR (95% CI) 1.6 (1.2, 2.0)(P = .001) and 3 of the 4 balance control systems (Anticipatory Adjustment, Sensory Orientation, Stability in Gait) were significantly associated with self-reported balance problems (.001 ≤ P ≤ .01). The strongest association was seen between Sensory Orientation and balance problems, implying that it is 4.4 times more likely that persons would have no or occasional balance problems with each unit of increase in Sensory Orientation. The total score for the Mini-BESTest was significantly associated with FUNC (P = .042).ConclusionsThe dynamic balance of persons with LSS showed a large heterogeneity with a large fraction of the participants displaying no balance impairments. The test results were associated with the participants’ self-reported balance problems and walking function. The Mini-BESTest thus appears to provide additional information to self-reported disability, and by identifying different kind of balance control impairments, the Mini-BESTest could be useful for physiotherapists working with person-centered rehabilitation in persons with LSS.

Knee flexor strength and balance control impairment may explain declines during prolonged walking in women with mild multiple sclerosis

BackgroundPhysiological factors such as muscle weakness and balance could explain declines in walking distance by multiple sclerosis (MS) patients. The purpose of this study was to characterize levels and examine associations among decline in walking distance, balance and muscular strength in women with mild MS. MethodsParticipants included 28 women with mild relapsing-remitting MS and 21 women without MS. We executed the 6-min walk test (6MWT) to verify declines in walking distance. Isokinetic knee flexion (KF) and extension (KE) muscle strength was measured using a dynamometer. Balance was quantified using a force platform, with eyes open and closed, on a rigid and foam surface. ResultsThe MS patients presented declines in walking, lower KF muscle strength, and worse balance than controls. KF strength and balance correlated with walking in the MS group. The KF strength explained differences between groups in walking. The KF strength and balance presented as predictors of walking slowing down in the 6MWT, in mild MS. ConclusionWomen with mild MS have strength impairment of knee flexor muscles and balance control impairment that may explain walking related motor fatigability during prolonged walking.

The iFST: An instrumented version of the Fukuda Stepping Test for balance assessment

The maintenance of the upright posture during dynamic balance requires the integration of sensory inputs regulated by the brain. After a neurological event, the assessment of balance control impairments is crucial for supporting health professionals in the design of personalized rehabilitation protocols. A commonly used test to assess balance ability is the Fukuda Stepping Test (FST). However, the clinical parameters traditionally considered are not fully representative of the patient’s motor ability. The purpose of this study was to devise an instrumented version of the FST (iFST) that embodies inertial sensors and allows to obtain individual motor strategy information. Twenty-seven sub-acute stroke patients and 18 healthy adults performed a repeated stepping task with closed eyes wearing five inertial sensors located on both distal tibiae and at pelvis, sternum, and head levels. From final foot position, body rotation and linear displacements were measured. A set of indices related to upper-body stability were estimated from pelvis, sternum, and head accelerations: Root Mean Square, Attenuation Coefficients, and improved Harmonic Ratio. Two additional parameters based on upper-body angular velocities were devised to assess step-by-step repeatability and inter-segment velocity variations. The results suggest that the clinical parameters do not provide enough information about the two groups’ motor strategies. Conversely, five iFST parameters were identified as predictors of patients’ motor ability, discriminating not only between healthy and pathological subjects, but also between different motor deficit levels within the same pathology. The iFST could be included in the clinical routine assessment of balance impairments, supporting the design of personalized treatments.

Change in the natural head-neck orientation momentarily altered sensorimotor control during sensory transition

Achilles tendon vibration generates proprioceptive information that is incongruent with the actual body position; it alters the perception of body orientation leading to a vibration-induced postural response. When a person is standing freely, vibration of the Achilles tendon shifts the internal representation of the verticality backward thus the vibration-induced postural response realigned the whole body orientation with the shifted subjective vertical. Because utricular otoliths information participates in the creation of the internal representation of the verticality, changing the natural orientation of the head-neck system during Achilles tendon vibration could alter the internal representation of the earth vertical to a greater extent. Consequently, it was hypothesized that compared to neutral head-neck orientation, alteration in the head-neck orientation should impair balance control immediately after Achilles tendon vibration onset or offset (i.e., sensory transition) as accurate perception of the earth vertical is required. Results revealed that balance control impairment was observed only immediately following Achilles tendon vibration offset; both groups with the head-neck either extended or flexed showed larger body sway (i.e., larger root mean square scalar distance between the center of pressure and center of gravity) compared to the group with the neutral head-neck orientation. The fact that balance control was uninfluenced by head-neck orientation immediately following vibration onset suggests the error signal needs to accumulate to a certain threshold before the internal representation of the earth vertical becomes incorrect.

Balance Impairments in Different Subgroups of Patients With Migraine.

Patients with migraine often experience balance impairments. However, the relationship between clinical features - like aura and chronicity - and the severity of balance impairments is not well established. The objective of this study was to assess balance impairments in different subgroups of migraine patients. One hundred five subjects diagnosed according to the ICHD-III were recruited in the study. They were uniformly distributed among three groups: migraine with aura, migraine without aura, and chronic migraine. Thirty-five controls were also recruited in the study. Balance impairments were assessed in all subjects via the modified Sensory Organization test and the Limits of Stability test. The results in the four groups were compared using ANCOVA tests with age, BMI, presence of dizziness, level of physical activity, time of migraine onset, and medication intake as covariates. Subjects in the migraine with aura and the chronic migraine groups showed poorer balance control than control subjects in three of the four conditions tested using the modified Sensory Organization test: FirmCE: CG: 1.5 cm2 , 95%CI 1.3 to 1.7; M: 2.1 cm2 , 95%CI 1.6 to 2.6; MA: 4.5 cm2 , 95%CI 3.2 to 5.8; CM: 4.5 cm2 , 95%CI 3.0 to 6.0; P < .027; FoamOE: CG: 5.1 cm2 , 95%CI 4.6 to 5.6; M: 5.6 cm2 , 95%CI 5.0 to 6.1; MA: 8.8 cm2 , 95%CI 7.3 to 10.2; CM: 8.8 cm2 , 95%CI 7.7 to 10.0; P < .018; FoamCE: CG: 14.8 cm2 , 95%CI 13.7 to 15.9 cm2; M: 17.3 cm2 , 95%CI 15.4 to 19.1; MA: 21.9 cm2 , 95%CI 19.1 to 24.7; CM: 22.4 cm2 , 95%CI 19.9 to 24.9; P < .0001. In the FoamOE and FoamCE conditions, both groups also showed poorer postural control than subjects in the migraine without aura group (P < .01). Differences between control subjects and subjects in all the migraine groups were found in the reaction time, movement velocity, endpoint excursion, and maximal excursion parameters (P < .04) in all the directions tested during the Limits of Stability test. None of the covariates appeared to affect the balance parameters (P > .05). There is evidence of balance control impairments in subjects with all subtypes of migraine compared to control subjects. The presence of aura and frequent migraine attacks reflect negatively in the postural control performance and may have a significant clinical impact in patients with migraine that should be addressed with appropriate clinical interventions.

Postural control in degenerative diseases of the hip joint

BackgroundFew studies investigated the postural control in patients with hip joint impairments; in some cases, balance impairments have been found, while other researchers have seen no significant changes. The goal of this study was to characterize postural stability in patients suffering from unilateral osteoarthritis or rheumatoid arthritis in different balance tasks and to reveal potential differences between the two diseases in this respect. MethodsTen patients with hip osteoarthritis (mean age: 62.3years), 10 patients with rheumatoid arthritis (mean age: 55.4years) and 10 healthy control subjects (mean age: 54.3years) took part in the study. Displacement of centre of pressure was measured with a force plate in mediolateral and anteroposterior directions during two-leg standing on firm and compliant surfaces with eyes opened and closed. FindingsStanding on a firm surface sway path increased significantly in the anteroposterior direction in both patient groups and in the mediolateral direction in all groups with eyes closed as compared to eyes opened condition. Standing on a compliant surface, sway paths increased significantly in both directions in all groups with eyes closed as compared to eyes opened condition; furthermore, sway paths were significantly longer with eyes closed in patients with rheumatoid arthritis in comparison with control and osteoarthritis groups. InterpretationOur data revealed that the manipulation of both visual and somatosensory information can reveal subtle impairments in balance control. Thus, this paradigm can unmask the effects of decreased proprioception due to joint capsule lesion in patients with rheumatoid arthritis.

Acute effects of Dry Immersion on kinematic characteristics of postural corrective responses

Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

Sensory reweighting is altered in adolescent patients with scoliosis: Evidence from a neuromechanical model

Idiopathic scoliosis is the most frequent spinal deformity in adolescence. While its aetiology remains unclear, impairments in balance control suggest a dysfunction of the sensorimotor control mechanisms. The objective of this paper is to evaluate the ability of patients with idiopathic scoliosis to reweigh sensory information. Using a neuromechanical model, the relative sensory weighting of vestibular and proprioceptive information was assessed. Sixteen healthy adolescents and respectively 20 and 16 adolescents with mild or severe scoliosis were recruited. Binaural bipolar galvanic vestibular stimulation was delivered to elicit postural movement along the coronal plane. The kinematics of the upper body, using normalized horizontal displacement of the 7th cervical vertebra, was recorded 1s before, 2s during, and 1s following vestibular stimulation. The neuromechanical model included active feedback mechanisms that generated corrective torque from the vestibular and proprioceptive error signals. The model successfully predicted the normalized horizontal displacement of the 7th cervical vertebra. All groups showed similar balance control before vestibular stimulation; however, the amplitude (i.e., peak horizontal displacement) of the body sway during and immediately following vestibular stimulation was approximately 3 times larger in patients compared to control adolescents. The outcome of the model revealed that patients assigned a larger weight to vestibular information compared to controls; vestibular weight was 6.03% for controls, whereas it was 13.09% and 13.26% for the mild and severe scoliosis groups, respectively. These results suggest that despite the amplitude of spine deformation, the sensory reweighting mechanism is altered similarly in adolescent patients with scoliosis.

Diurnal variation on balance control in patients with symptomatic knee osteoarthritis

ObjectiveIncreasing evidence supports balance control impairment in older adult patients with knee osteoarthritis (OA). However, there is limited data on diurnal variation of balance control in these patients. This study aimed to investigate postural stability in older adult patients with symptomatic knee OA during different periods in a daytime. MethodsTwo-hundred and forty-one patients with OA knee (median age=65±12 years; 82 males) were enrolled in this study. Static posturography was performed under four standing conditions: eyes open and eyes closed, without and with foam support. To assess diurnal postural variations, testing sessions were defined as follows: 8–10am, 10–12am, 1pm–3pm, 3pm–5pm. Influence of sex, age, height, weight, and body mass index on postural stability was evaluated. Knee pain was also assessed in these four testing sessions. ResultsPostural control was in particular less efficient in the late morning than in the early afternoon (p<0.05). Diurnal variation of balance control was more noticeable in older, heavier, and male patients (p<0.05). Patients’ knee pain was more pronounced in the morning than in the afternoon (p<0.001). ConclusionBalance stability of patients with OA knee was different during a daytime. Altered postural performance in the morning could be explained by joint pain. This diurnal variation should be taken into account in the daily management of knee OA.

Tailored balance exercises on people with multiple sclerosis: A pilot randomized, controlled study

Background: Altered integration of signals from visual (VIS), somatosensory (PROP) and vestibular system (VEST) lead to balance control impairments affecting the daily living activities of patients with multiple sclerosis (PwMS). As a consequence, tailored interventions could be crucial in improving efficacy of balance rehabilitation treatments. Objective: The objective of this paper is to assess the efficacy of tailored rehabilitation treatments for balance disorders based on visual, somatosensory and vestibular deficits versus traditional rehabilitation exercises. Methods: Thirty-two PwMS were assessed with the Berg Balance Scale (BBS), the composite score (CS) obtained by computerized dynamic posturography (CDP) test and the Modified Fatigue Impact Scale (MFIS). Based on CDP analysis, prevalent VIS, PROP or VEST deficits were identified and patients randomly allocated to a personalized (PRG) or traditional (TRG) rehabilitation group. Results: BBS score showed a significant difference between pre- and post-treatment scores of 6.3 and 2.0 points respectively for PRG and TRG. CS showed a significant difference between pre- and post-treatment scores of 16.6 and 7.6 points respectively for PRG and TRG. No interaction effect was found for MFIS score. Conclusions: BBS and CS showed changes in the PRG group that met clinical relevant difference, underlining that tailored rehabilitation interventions based on patient-specific sensory system impairment could improve balance and postural control in PwMS.

Balance control impairment in obese individuals is caused by larger balance motor commands variability

It is acknowledged that various factors impaired balance control. Among them, heavy body weight is associated with poor balance control because the location of the center of mass is further away from the ankle joint. Thus, a larger active ankle torque is required to counter the greater gravitational torque. Because balance motor commands have signal-dependent noise whose standard deviation increases with the absolute value of the neural control signal, it was hypothesized that faster center of pressure speed observed in obese individuals would be related to larger balance motor commands variability. A feedback-control model and parametric system identification technique was used to estimate the variability in the balance motor commands and neural controller parameters based on previously published experimental data. Results of the neuromechanical model confirmed that the balance motor commands of obese individuals are more variable than that of lean individuals.

Balance control impairment induced after OKS in patients with vestibular migraine: an intercritical marker.

The aim of the study was to assess the effects of optokinetic stimulation (OKS) on vestibular postural control in migraine patients with recurrent vertigo. 15 patients with vestibular migraine (VM) were enrolled in a posturographic study in eyes open (OE) and eyes closed (CE) condition. The tests were performed between attacks of headache and vertigo at three different time: before, during, and 60 min after OKS. Data of patients with VM were compared with those obtained from two control groups matched for sex and age (15 for each group): (a) normal subjects not suffering from migraine without history of recurrent vertigo (N group); (b) subjects suffering from migraine with no history of recurrent vertigo (M group). Mean sway path velocity and sway area were analyzed. OKS increased the instability in all groups during the stimulus, and both the velocity and area values were higher in M and VM group. However, there was not significant difference between these two groups when stability was examined in OE condition before, during and after OKS stimulation. Conversely, in CE condition a significant greater instability was induced after OKS stimulation only in VM. In particular, post-stimulus values were significantly higher than the pre-stimulus one only in this group, while no significant difference was observed in other groups. A spatial analysis of the sway area evidenced that the instability induced by the OKS in VM group occurred along the direction of OKS. We suggest that this enhanced instability observed after OKS during the intercritical period may be considered an useful marker to support the diagnostic definition of VM in the absence of other vestibular signs.

Changes of the gait parameters and sensory-motor deficit associated with peripheral diabetic neuropathy

Peripheral nervous system impairment with sensory and motor loss, as observed in diabetic neuropathy, might induce severe effects on balance control and gait in this population. Objective: To evaluation the performance of the gait and the sensory-motors changes, due of the peripheral diabetic neuropathy (PDN). Method: Participated twenty four individuals with PDN and twenty eight healthy individuals without glycemic alterations indicative of diabetes. Participants were subjected to confirm the clinical diagnosis of diabetic neuropathy through the tactile sensitivity of the soles of the feet with monofilament test. Subsequently, ankle angular variation in static condition and during the gait was investigated through kinematics. The ankle muscle strength was investigated using a digital dynamometer. Results: Diabetic neuropathy group showed greater duration in double support and full support periods of gait than control group with impairment in balance control. Diabetic neuropathy group showed reduces muscle strength of plantiflexors and dorsiflexors. Conclusion: The losses sensory-motors deriving from PDN may imply in impairment in gait performance, with consequent loss of balance.

Regulation of whole-body frontal plane balance varies within a step during unperturbed walking

This study sought to determine whether the need to actively control lateral balance is consistent within a step. Variability of the frontal plane COM-Ankle angle was calculated over 50 strides at discrete gait events for twenty-one healthy young adults to quantify active control of lateral balance within a step. Frontal plane COM-Ankle angle variability was found to vary significantly between all gait events, decreasing progressively within a step. This suggests that active control of lateral balance varies significantly within a step and that the greatest degree of active control occurs at heel-strike. The increased active control of lateral balance during heel-strike indicates a degree of preparation to ensure sufficient lateral balance control prior to more challenging events. These results provide insight into the mechanisms of lateral balance control and how to assess and treat locomotor balance control impairments.