Postural Response Latencies Are Related to Balance Control During Standing and Walking in Patients With Multiple Sclerosis

Objective

To understand and examine the relation between postural response latencies obtained during postural perturbations and representative measures of balance during standing (sway variables) and walking (trunk motion).

Design

Cross-sectional.

Setting

University medical center.

Participants

Persons with multiple sclerosis (MS) (n=40) were compared with similar aged control subjects (n=20). There were 20 subjects with MS in the normal walking velocity group and 20 subjects with MS who had slow walking velocity based on a timed 25-foot walk (T25FW) of <5 seconds.

Interventions

None.

Main Outcome Measures

Postural response latency, sway variables, trunk motion variables.

Results

We found that subjects with MS with both slow or normal walking velocities had significantly longer postural response latencies than the healthy control group. Postural response latency was not correlated with the T25FW. Postural response latency was significantly correlated with center of pressure sway variables during quiet standing (root mean square: ρ=.334, P=.04; range: ρ=.385, P=.017; mean velocity: ρ=.337, P=.038; total sway area: ρ=.393, P=.015). Postural response latency was also significantly correlated with motion of the trunk during walking (sagittal plane range of motion: ρ=.316, P=.05; SD of transverse plane range of motion: ρ=−.43, P=.006).

Conclusions

These findings clearly indicate that slow postural responses to external perturbations in patients with MS contribute to disturbances in balance control during both standing and walking.     

A retrospective analysis of balance control parameters in elderly fallers and non-fallers

Background

A cross-sectional retrospective study of parameters reflecting balance function in elderly fallers and non-fallers was conducted to better understand postural control mechanisms in individuals prone to falls.

Methods

Ninety-nine old adults (65–91 years, mean age 78.4 (SD 5.7)) from two self-care residential facilities participated in the study. Foot center-of-pressure (CoP) displacement data were collected during narrow base upright stance eyes closed conditions and analyzed using summary statistics and Stabilogram-Diffusion Analysis (SDA) for mediolateral (ML) and anteroposterior (AP) directions. Subjects were instructed to minimize body sway.

Findings

Twenty-nine of the subjects reported at least one fall and 69 subjects reported no falls in the past six months. The SDA showed significantly higher short-term diffusion coefficients and critical displacements in fallers in the ML but not the AP direction. Mean sway area and ML-CoP sway range were also larger in fallers.

Interpretation

The greater ML critical displacement seen in fallers suggests that balance corrections on average occurred at higher sway amplitudes in this population. This is consistent with an ML decrease in the sensitivity of their postural control system. A higher short-term diffusion coefficient is consistent with increased muscle stiffness, a possible compensation for lost control sensitivity. Testing balance function under narrow stance conditions provides a modest increase in task difficulty that may help reveal pre-conditions of the balance control system that could increase the risk of falls.     

Changes in postural control in hemiplegic patients after stroke performing a dual task

Bensoussan L, Viton J-M, Schieppati M, Collado H, Milhe de Bovis V, Mesure S, Delarque A. Changes in postural control in hemiplegic patients after stroke performing a dual task.

Objective

To determine the effects of an attentional task on hemiplegic patients’ postural control performances.

Design

Retrospective study.

Setting

Department of physical and rehabilitation medicine at a university hospital.

Participants

Twenty-three hemiplegic patients and 23 healthy age- and sex-matched control subjects.

Interventions

Not applicable.

Main Outcome Measures

Sway area and sway path of the center of pressure were measured during 30 seconds in standing subjects and patients under 3 conditions: eyes open (EO), EO while performing a simple arithmetic task (EO-AT), and eyes closed (EC).

Results

In the hemiplegic patients, the body sway area increased significantly with EC (P<.001) and during the EO-AT task (P<.017) in comparison with EO. Sway area with EO-AT remained, however, significantly smaller than with EC (P<.014). In the healthy subjects, the body sway did not differ significantly between the EO-AT and EO tasks (P<.42). The increase observed in the sway area and path in the hemiplegic population during the EO-AT task correlated significantly with age.

Conclusions

The postural performances of hemiplegic patients decreased during both the arithmetic task and the EC task. The cognitive task had no effect on healthy subjects’ postural performances. This study is the first to show the combined effects of age and dual task on the postural performances of hemiplegic subjects.     

Peripheral neuropathy may not be the only fundamental reason explaining increased sway in diabetic individuals

Background

Individuals with diabetic neuropathy sway more than control individuals while standing. This review specifically evaluated whether peripheral sensory neuropathy can be the only fundamental reason accounting for significant increased sway within this population.

Methods

Twenty-six experimental articles were selected using MEDLINE and reference lists of relevant articles. The articles chosen investigated kinematic data of postural behaviour in controls and individuals with diabetic neuropathy during stance. Results of literature were compared with four expectations related to the peripheral sensory neuropathy fundamental hypothesis.

Findings

Consistent with the peripheral sensory neuropathy hypothesis, the literature showed that individuals with diabetic neuropathy sway more than controls in quiet stance and even more so if their visual or vestibular systems were perturbed. Inconsistent with the hypothesis, individuals with diabetic neuropathy are more destabilised than controls in conditions altering sensation of the feet and legs (standing on a sway-referenced surface).

Interpretation

The review showed that the peripheral sensory neuropathy hypothesis may not be the only fundamental cause accounting for significant increased postural sway in individuals with diabetic neuropathy. Visual impairments and changes in postural coordination may explain the divergence between expectations and results. In order to develop interventions aimed at improving postural control in individuals with diabetic neuropathy, scientific exploration of these new expectations should be detailed. Also at the practical level, the review discussed which additional sensory information – at the level of the hands and feet – may be more beneficial in individuals with diabetic neuropathy to reduce their postural sway.     

Assessing subclinical tactual deficits in the hand function of diabetic blind persons at risk for peripheral neuropathy

Travieso D, Lederman SJ. Assessing subclinical tactual deficits in the hand function of diabetic blind persons at risk for peripheral neuropathy.

Objective

To assess subclinical impairments in tactual hand function produced by diabetes mellitus in late-blind adults with diabetic retinopathy.

Design

The survey compares diabetic blind with nondiabetic blind and blindfolded sighted controls in terms of their performance on a battery of tests that assess tactual hand function.

Setting

Subjects were evaluated at their rehabilitation program center in Madrid.

Participants

Nine (referred) diabetic blind subjects affected by diabetic retinopathy versus 10 (referred) nondiabetic blind subjects versus 10 blindfolded sighted volunteers, all right-handed and matched for age. Subjects were referred by the training professionals of the rehabilitation program center and asked to volunteer.

Interventions

Not applicable.

Main Outcome Measures

Cutaneous force and spatial resolution thresholds, haptic psychophysical functions for perceived roughness, weight, and size, and both accuracy and response times for haptic classification of 3-dimensional common objects. Measures of joint mobility, muscular strength, and motor dexterity were also included.

Results

The diabetic blind performed significantly poorer than the controls in terms of force sensitivity (distal and proximal finger pads, and palm), spatial resolution (distal finger pad only), motor dexterity, perceived roughness, and finally, haptic object classification response times for texture-diagnostic objects.

Conclusions

Subclinical disturbances in the tactual hand function of the diabetic blind subjects were only documented in perceptual and motor tasks for which cutaneous, as opposed to kinesthetic, information was particularly relevant.     

Between-limb synchronization for control of standing balance in individuals with stroke

Background

During standing, forces and moments exerted at the feet serve to maintain stability in the face of constant centre-of-mass movement. These actions are temporally synchronized in healthy individuals. Stroke is typically a unilateral injury resulting in increased sensori-motor impairment in the contra-lesional compared with the ipsi-lesional lower-limb, which could lead to reduced between-limb synchronization for control of standing balance. The purpose of this study is to investigate between-limb synchronization of standing balance control in individuals with stroke; a potentially important index of control of upright stability.

Methods

Twenty healthy controls and 33 individuals with unilateral stroke were assessed. Stability was assessed during a 30-second quiet standing trial by measuring data from two force plates (one per foot). Limb-specific centre of pressure was calculated. Between-limb synchronization was defined as the coefficient of the correlation between the left and right foot for both the antero-posterior and medio-lateral centre of pressure time series. Synchronization, weight-bearing symmetry, and root mean square of the total centre of pressure excursion were compared between controls and stroke participants.

Findings

Stroke participants swayed more, were more asymmetric, and had less between-limb synchronization than healthy controls. Among individuals with stroke, reduced between-limb synchronization was related to increased postural sway in the medio-lateral direction and increased weight-bearing asymmetry.

Interpretation

Individuals with stroke have reduced temporal synchronization of centre of pressure fluctuations under the feet when controlling quiet standing. The clinical significance of reduced synchronization remains to be determined, although it appears linked to increased medio-lateral sway and weight-bearing asymmetry.     

The evaluation of walking footwear on postural stability in healthy older adults: an exploratory study

Background

It has been proposed that walking footwear enhances postural stability in healthy older adults. The aim of the study is to evaluate differences between two different types of athletic footwear in relation to postural stability in healthy older adults.

Methods

A convenience sample of 21 healthy older adults with mean (SD) of 74 (5) years was recruited. Postural stability was measured using a force plate for anterior–posterior (AP) and mediolateral (ML) centre of pressure excursion for 30 s with eyes closed and open using two different types of athletic footwear. Each participant performed three repetitions of bipedal standing. Two-way analysis of variance tested the interaction effect of the footwear and eye conditions on anterior–posterior (AP) and mediolateral (ML) postural sway.

Findings

There was no significant footwear–eye condition interaction for anterior-posterior(AP) postural sway but there were significant main effects for both the footwear and eye conditions (P < 0.05). The significant main effects for the footwear conditions occurred between barefeet and the two shoe conditions, but not between the two shoe conditions. For mediolateral (ML) postural sway there was no significant interaction effect and no main effects for the footwear and eye conditions (P > 0.05).

Interpretation

The results suggest that older adults demonstrate an initial destabilisation effect which could possibly be of benefit to functional ability but the long-term effects of ability of athletic footwear to enhance postural stability requires further investigation.     

Voluntary sway and rapid orthogonal transitions of voluntary sway in young adults,and low and high fall-risk older adults

Background

Falls amongst older people have been linked to reduced postural stability and slowed movement responses. The objective of this study was to examine differences in postural stability and the speed of response between young adults, low fall-risk older adults, and high fall-risk older adults during voluntary postural sway movements.

Methods

Twenty-five young adults (25 ± 4 years), and 32 low fall-risk (74 ± 5 years), and 16 high fall-risk (79 ± 7 years) older adults performed voluntary sway and rapid orthogonal transitions of voluntary sway between the anterior–posterior and medial–lateral directions. Measures included reaction and movement time and the amplitudes of the centre of pressure, centre of mass, and the separation distance between the centre of pressure and centre of mass.

Findings

Both fall-risk groups compared to the young had slower reaction and movement time, greater centre of pressure and/or centre of mass amplitude in the orthogonal (non-target) direction during voluntary sway, and reduced anterior–posterior and medial–lateral separation between the centre of pressure and centre of mass during voluntary sway and orthogonal transitions. High compared to low fall-risk individuals had slower reaction and movement time, increased non-target centre of mass amplitude during voluntary sway, and reduced medial–lateral centre of pressure and centre of mass separation during voluntary sway and orthogonal transitions.

Interpretation

Age-related deterioration of postural control resulted in slower reactive responses and reduced control of the direction of body movement during voluntary sway and orthogonal transitions. Slower postural reaction and movement time and reduced medial–lateral control of the centre of mass during voluntary sway movements are associated with increased fall-risk in community-living older people.     

Lower-extremity kinematics and postural stability during stair negotiation: Effects of two cognitive tasks

Background

Concurrent cognitive tasks were found to affect gait characteristics during level walking, such as decreasing speed, cadence, step length, etc. Given that many accidents occur during stair negotiation and people often perform cognitive tasks concurrently with stair negotiation in daily life, there is a need to study how cognitive tasks affect gait characteristics and postural stability during stair negotiation. This study aimed to determine cognitive task effects on lower-extremity kinematics and postural stability during stair negotiation. We also examined the difference in cognitive demands between ascent and descent.

Methods

Two cognitive tasks, i.e. ‘backward digit recall’ and ‘counting backward in threes’, were examined. There were three testing conditions corresponding to a baseline and the two cognitive tasks, respectively. In the baseline, no cognitive task was performed. In the cognitive task conditions, the cognitive task was performed continuously throughout the stair negotiation trial. Each participant performed six ascent trials and six descent trials under each testing condition. We measured the cognitive task performance. Lower-extremity kinematics and postural stability were calculated using the data collected from a complete stair gait cycle that was obtained for the dominant leg.

Findings

In general, concurrent cognitive tasks had adverse effects on lower-extremity kinematics and postural stability during both ascent and decent. No differences in dependent measures were found between cognitive tasks. Additionally, ascent and descent appeared to be equally cognitively demanding.

Interpretation

The findings from this study can help better understand inadequate postural reactions due to cognitive load that may cause stair accidents.     

Attentional control of postural stability in institutionalised elderly people: effects of a physical exercise program]

OBJECTIVE: We aimed to examine the effect of a physical activity program on postural sway and on the attentional control of postural abilities in elderly frail adults. METHOD: Twelve older adults (age 81.4+/-9 years) institutionalised in a geriatric care institution participated in the physical activity program posture-balance-mobility (PBM) twice a week (1 hour per session) for 12 weeks. We analysed stabilometric data for surface and length of the center of pressure (COP) sway, with eyes open and eyes closed, under single-task and dual-task conditions on a firm floor before and after the training program. During the static postural evaluation and under the dual-task condition, subjects performed an attention-demanding cognitive task, the random number generation task. RESULTS: Only the length of COP sway was more important under the dual-task condition than under the single-task condition (p=0.05). At baseline, cognitive performance was significantly weaker under the dual-task condition (standing) than under the single-task condition (seated), with eyes closed but not eyes open (p<0.05). However, after the training program, the performance of the cognitive task did not significantly differ between the dual-task condition with eyes closed and the single-task condition with eyes closed. CONCLUSION: The training program allowed elderly subjects to improve their ability to perform an attention-demanding cognitive task while standing still, in particular with their eyes closed. Although balance seemed to be less stable under the dual-task condition than under the single-task condition, these results could be interpreted as an improvement of the attentional control of postural stability.     

Multiple Sclerosis and Postural Control: The Role of Spasticity

Sosnoff JJ, Shin S, Motl RW. Multiple sclerosis and postural control: the role of spasticity.

Objectives

To examine the association between spasticity and postural control in subjects with multiple sclerosis (MS).

Design

Cross-sectional.

Setting

Motor control laboratory.

Participants

Subjects with MS (n=16, 2 male) and age and sex-matched subjects (n=16) participated in the investigation. All subjects with MS had Expanded Disability Status Scale scores between 0 and 4.5 and modified Ashworth scale scores between 1 and 3.

Interventions

Not applicable.

Main Outcome Measures

Postural control was measured with a force platform that quantifies ground reaction forces and moments in mediolateral and anteroposterior directions. Postural control was indexed with anterior-posterior sway range, medial-lateral sway range, 95% elliptical area of the deviations of center of pressure (COP), velocity of COP sway, and the frequency at which 95% of spectral profile was contained. Participants with MS further underwent assessment of the soleus Hoffman reflex (H-reflex) as an index of spasticity.

Results

Cluster analysis on H-reflex data identified groups of MS participants with high spasticity (n=7) and low spasticity (n=9). There were no differences in age, duration of MS, and disease severity between MS groups. There were no differences in anterior-posterior sway range between any of the groups. The high spasticity group had greater COP area, velocity, and mediolateral sway compared with the low spasticity and control group, and the low spasticity group had postural control values between the high spasticity and control groups.

Conclusions

The pattern of results suggests that spasticity contributes to postural deficits observed in MS.     

Nonlinear analysis of sitting postural sway indicates developmental delay in infants

Background

Upright sitting is one of the first developmental motor milestones achieved by infants, and sitting postural sway provides a window into the developing motor control system. A variety of posture sway measures can be used, but the optimal measures for infant development have not been identified.

Methods

We have collected sitting postural sway data from two groups of infants, one with typical development (n = 33), and one with delayed development and either diagnosed with or at risk for cerebral palsy (n = 26), when the infants had developed to the point where they could just maintain sitting for about 10 s. Postural sway data was collected while infants were sitting on a force platform, and the center of pressure was analyzed using both linear and nonlinear measures.

Findings

Our results showed that a nonlinear measure, the largest Lyapunov exponent, was the only parameter of postural sway that revealed significant differences between infants with typical versus delayed development. The largest Lyapunov exponent was found to be higher for typically developing infants, indicating less repeated patterning in their movement coordination.

Interpretations

A nonlinear measure such as largest Lyapunov exponent may be useful as an identifier of pathology and as a yardstick for the success of therapeutic interventions.     

A Preliminary Study to Identify Locomotor-Cognitive Dual Tasks That Reveal Persistent Executive Dysfunction After Mild Traumatic Brain Injury

Objective

To identify different combinations of physical (level, obstacle avoidance, stepping down) and cognitive (visual, mental) demands within a locomotor navigational context that best discriminates between persons with mild traumatic brain injury (MTBI) and control subjects for an eventual clinical tool to assess residual executive dysfunction.

Design

Group comparison study.

Setting

Rehabilitation facility.

Participants

Volunteer sample (N=14) of persons with MTBI (n=7) (6 women; age, 20±1.6y) and a comparison group (n=7) of subjects without neurologic problems (6 women; age, 22.4±1.4y).

Interventions

Not applicable.

Main Outcome Measures

Gait speed (m/s) and dual-task cost calculated as the relative change in gait speed from single (no cognitive task) to dual tasks for the same gait condition.

Results

There were significant interactions between groups and cognitive tasks and between groups and cognitive and physical tasks for gait speed. Specifically, the MTBI group walked slower than control subjects in the dual-task conditions when stepping over an obstacle combined with each cognitive task. When gait speed was measured as dual-task costs, group differences were more evident, except for stepping down.

Conclusions

These preliminary results suggest that both absolute gait speed and calculated dual-task costs during the combination of stepping over an obstacle with a simultaneous cognitive task are sensitive to revealing executive dysfunction in persons with MTBI. Gait speed can be easily measured in the clinic to provide important information to make diagnoses and decide about return to play or function. Continued work building on these preliminary results is needed toward the development of a clinical tool.     

The effects of sandals on postural stability in patients with rheumatoid arthritis: An exploratory study

Background

Rheumatoid arthritis results in postural instability, pain and functional limitations. As rheumatoid arthritis progresses, localised forefoot deformities such as hallux valgus and clawing of the lesser toes occur, leading to a high proportion of people with rheumatoid arthritis wearing sandals. Sandals may affect postural stability due to poor motion control. The aim was to assess two different open-toe sandals on postural stability in people with rheumatoid arthritis.

Methods

Twenty women with rheumatoid arthritis were assessed in quiet standing under four conditions: (1) open-back sandal; (2) closed-back sandal; (3) own footwear and (4) bare feet. Postural stability was assessed as postural sway in the anterior-posterior and medial-lateral directions, with eyes open and eyes closed, using a pressure mat. Repeated measures analysis of variance tested the interaction effect of the footwear and eye conditions on anterior-posterior and medial-lateral sway.

Findings

In eyes-open, there was no significant difference in anterior–posterior sway (P = .169) and medial-lateral sway (P = .325) for footwear conditions. In eyes-closed testing, compared with barefoot conditions, increased anterior–posterior sway was observed with participants' footwear (P < .0001), the open-back sandal (P = .005), and the closed-back sandal (P = .017). With eyes closed, increased anterior–posterior sway was also observed with the participants' footwear compared with the closed-back sandal (P = .041). Increased medial-lateral sway was observed with the closed-back sandal compared with bare feet (P = .014).

Interpretation

Sandals may be detrimental to older women with well-established rheumatoid arthritis when eyes are closed. Further investigation is needed to evaluate the effect of sandals on dynamic tasks.     

Experimental calf muscle pain attenuates the postural stability during quiet stance and perturbation

Background

The purpose of this study was to evaluate how acute pain changes the postural control and stability during quiet standing and after unexpected perturbations.

Methods

Nine subjects stood as quiet as possible on a movable force platform that recorded the centre of pressure position and provided unexpected floor perturbations, before, during and after experimental calf muscle pain. Bilateral surface electromyography from the tibialis anterior and medial gastrocnemius muscles was recorded. The foot pressure distributions were measured using pressure insoles. Intramuscular injections of hypertonic saline were administrated (right leg) to induce acute pain in the tibialis anterior and/or medial gastrocnemius muscles, and an isotonic injection was used as control.

Findings

Simultaneous pain in tibialis anterior and medial gastrocnemius altered the postural control. During quiet standing: higher medial-lateral centre of pressure speed and increased total sway displacement (P < 0.05), weight moved to the non-painful side, (P < 0.05) and plantar centre of pressure of the left foot was shifted towards the heel’s direction (P < 0.05). During forward perturbation: higher mean displacement in the medial-lateral direction (P < 0.05). After the perturbation: larger sway area (P < 0.05). Pain only in the medial gastrocnemius muscle increased medial-lateral centre of pressure speed (P < 0.05) during the quiet standing. Pain only in the tibialis anterior muscle increased peak pressure on the contralateral foot (P < 0.05).

Interpretation

These findings suggest that large acute painful areas on the calf muscles impair the postural control and potentially increase the risk factors for falls. Further strategies aiming to reduce pain in patients may lead to improvement in balance.     

Effect of Dual-Tasking on Dynamic Postural Control in Individuals With and Without Nonspecific Low Back Pain

Objective

The purpose of this study was to compare the effect of dual tasking on postural and cognitive performance between participants with and without nonspecific chronic low back pain.

Methods

In this 3-factor mixed-design study, dynamic postural stability was assessed in 15 patients with chronic nonspecific low back pain and 15 age-, sex-, and size-matched asymptomatic participants. Bilateral stance on a Biodex Balance System was investigated at 3 levels of postural task difficulty (different platform stabilities levels with eyes open and closed) and 2 levels of cognitive task difficulty (with or without auditory Stroop test). We measured anterior-posterior, medial-lateral, and overall indices for postural performance. Average reaction time and error ratio of a modified auditory Stroop test were calculated as measures of the cognitive task performance.

Results

Mixed-design 3-way analyses of variance revealed significant interactions. Post hoc 2-way analyses of variance showed significant group by cognitive task difficulty for anterior-posterior (P < .001), medial-lateral (P = .003), and overall stability indices (P < .001) on a stiffness level of 5 with eyes closed. At this level, there were significant differences between single- and dual-task conditions for anterior-posterior (P < .001), medial-lateral (P = .02), and overall stability indices (P < .001) only in the chronic low back pain group. Also, at the most difficult postural conditions, participants with chronic low back pain increased their error ratio (P = .002), whereas matched asymptomatic individuals increased their reaction time (P < .01) of the auditory Stroop test.

Conclusion

Postural task performance is attenuated by cognitive loading at a moderate level of postural task difficulty. Therefore, to observe the effect of attentional demands of postural control, task difficulty should be considered.     

Postural control is altered in patients with ankylosing spondylitis

Background

Ankylosing spondylitis is a chronic inflammatory disorder that can lead to increased axial and peripheral joint stiffness, impairing joint mobility. Impaired axial mobility due to vertebral ankylosis may result in changes in standing postural control. Little research has addressed changes in standing postural control in the ankylosing spondylitis population, nor how these issues might affect clinical understanding and treatment.

Methods

Sixteen ankylosing spondylitis patients, and 17 healthy controls participated. Each individual completed two 120-second quiet standing trials with eyes open and eyes closed, while standing upon two force platforms. Net center of pressure displacement and mean power frequency in the frontal and sagittal planes were calculated. A Spearman's rank correlation analysis was performed between net center of pressure measures and several clinical measures of disease activity.

Findings

Frontal plane net center of pressure displacement and frequency content, and sagittal plane net center of pressure displacement were significantly greater within the ankylosing spondylitis patient group. Ankylosing spondylitis patients demonstrated a significant increase in frontal plane net center of pressure displacement in the eyes-closed condition. Net center of pressure displacement and frequency were significantly correlated to the Bath Ankylosing Spondylitis Functional Index, and individual components of the Bath Ankylosing Spondylitis Metrology Index.

Interpretation

Quiet standing postural control was altered particularly so in the frontal plane in patients with ankylosing spondylitis, which may be associated with increased fall risk. Posturographic measures of postural control may serve as valuable clinical tools for the monitoring of disease progression and disease status in ankylosing spondylitis.     

Postural balance under normal and altered sensory conditions in normal-weight and overweight children

Background

Little or no research has been done in the overweight child on the relative contribution of multisensory information to maintain postural stability. Therefore, the purpose of this study was to investigate postural balance control under normal and experimentally altered sensory conditions in normal-weight versus overweight children.

Methods

Sixty children were stratified into a younger (7–9 yr) and an older age group (10–12 yr). Participants were also classified as normal-weight (n = 22) or overweight (n = 38), according to the international BMI cut-off points for children. Postural stability was assessed during quiet bilateral stance in four sensory conditions (eyes open or closed, normal or reduced plantar sensation), using a Kistler force plate to quantify COP dynamics. Coefficients of variation were calculated as well to describe intra-individual variability.

Findings

Removal of vision resulted in systematically higher amounts of postural sway, but no significant BMI group differences were demonstrated across sensory conditions. However, under normal conditions lower plantar cutaneous sensation was associated with higher COP velocities and maximal excursion of the COP in the medial-lateral direction for the overweight group. Regardless of condition, higher variability was shown in the overweight children within the 7–9 yr old subgroup for postural sway velocity, and more specifically medial–lateral velocity.

Interpretation

In spite of these subtle differences, results did not establish any clear underlying sensory organization impairments that may affect standing balance performance in overweight children compared to normal-weight peers. Consequently, it is believed that other factors account for overweight children's functional balance deficiencies.     

A Primary Care–Based Randomized Controlled Trial of 12-Week Whole-Body Vibration for Balance Improvement in Type 2 Diabetes Mellitus

Objective

To determine whether a 12-week whole-body vibration (WBV) training program improved balance in participants with type 2 diabetes mellitus (T2DM).

Design

Randomized controlled trial.

Setting

Primary health care setting.

Participants

Participants with T2DM (N=50).

Interventions

Participants were randomly allocated to either a WBV group (n=25), which performed a 12-week WBV-based exercise program on an oscillating platform (12–16Hz—4mm; 3 sessions/wk), or a usual-care control group (n=25).

Main Outcome Measures

Clinical and sociodemographic variables were recorded at baseline. Static balance and dynamic balance were also assessed at baseline by measuring postural sway (measurement of center of pressure [COP] excursions in the anteroposterior and mediolateral directions) using a Wii Balance Board and the Timed Up and Go test.

Results

Significant between-group differences in COP excursions with participants' eyes closed were found with their feet apart and feet together. In addition, participants in the WBV group exhibited significantly lower COP excursions with their eyes closed after the intervention, while participants in the control group experienced a nonsignificant deterioration in COP excursions (ie, greater excursion) with their eyes open (mediolateral axis). There was no significant difference in the Timed Up and Go test values postintervention.

Conclusions

WBV provides a safe and well-tolerated approach to improve balance in participants with T2DM. These findings may have important implications for falls prevention in those with T2DM in the primary health care setting.     

Postural Control and Functional Strength in Patients With Type 2 Diabetes Mellitus With and Without Peripheral Neuropathy

Objective

To assess the influence of diabetic neuropathy (DN) on balance and functional strength in patients with diabetes mellitus type 2 (DM2).

Design

Cross-sectional study.

Setting

Diabetes outpatient unit.

Participants

Adults (N=62; age range, 40–65y): 32 with DM2 (19 subjects without DN and 13 with DN) and 30 without DM2 (control group).

Interventions

Not applicable.

Main Outcome Measures

Upright balance, evaluated in 4 situations (fixed platform, unstable platform, with eyes open, with eyes closed), and functional strength, assessed with a five-times-sit-to-stand test, were analyzed using an electromagnetic system, with a sensor placed over C7 to allow maximum trunk displacements in the anterior-posterior and medial-lateral directions. The Berg Balance Scale and the Timed Up & Go test were also used.

Results

Subjects with DM2 had greater anterior-posterior displacement (P<.05) in the unstable platform with eyes closed condition compared with those without DM2, whereas no difference in medial-lateral displacement was observed between these groups. A difference in time was observed in the five-times-sit-to-stand test (P<.05), with subjects in the control group performing the tasks faster than either group of subjects with DM2. Additionally, subjects in the control group showed a higher score in the Berg Balance Scale and performed the Timed Up & Go test in less time compared with subjects in other groups.

Conclusions

Subjects with DM2, with or without DN, showed deficits in postural control and functional strength compared with healthy individuals of the same age group.