Fibular taping does not influence ankle dorsiflexion range of motion or balance measures in individuals with chronic ankle instability

ObjectivesTo determine the effects of fibular taping on ankle dorsiflexion range of motion (ROM) and dynamic balance in individuals with chronic ankle instability (CAI).DesignSingle-blind, randomized crossover.MethodsTwenty-three individuals (age = 23.4 ± 2.5 years, height = 171.6 ± 12.4 cm, mass = 71.5 ± 13.1 kg) with CAI were allocated to either a fibular taping intervention or sham taping intervention (tape applied without tension) over the course of two visits. Weight-bearing ankle dorsiflexion ROM and components of the Star Excursion Balance Test (SEBT) were measured before and after intervention.ResultsThere was not a significant change in ankle dorsiflexion ROM when comparing the taping interventions (F_1,43 = 1.03, P = .32), but both interventions resulted in a small increase (F_1,43 = 8.07, P = .007) in dorsiflexion ROM (pre = 36.7° ± 6.9°, post = 37.7° ± 6.2°). This increase in ROM did not exceed the established minimal detectable change for dorsiflexion ROM. Fibular taping with tension produced an increase (F_1,41 = 5.84, P = .02) (pre = 69.0 ± 9.1%, post = 70.6 ± 8.6%) in posterolateral reach distance when compared to taping without tension (pre = 72.7 ± 11.0%, post = 71.4 ± 9.6%), but this increase did not exceed the established minimal detectable change. There was not a significant change in dynamic balance between groups for the anterior (F_1,41 = 2.33, P = .14) and posteromedial (F_1,41 = .41, P = .53) reach directions.ConclusionsAlthough small changes in ankle dorsiflexion ROM and posterolateral reach distances were observed, these changes did not exceed established minimal detectable change values for these measures. These results suggest that the benefits of fibular taping are not related to an increase in ankle dorsiflexion ROM or dynamic balance.     

The influence of ankle support on postural control

Postural control assessments are commonly administered to athletes as part of a pre-season screening. Establishing a baseline level of function permits the clinician to compare post-injury results to normal functioning during the return to play decision-making process. In the athletic setting, follow-up tests may be completed on the sideline immediately following injury. We sought to examine the effect of commonly administered external ankle joint support on postural control using the balance error scoring system (BESS) and the NeuroCom sensory organization test (SOT). Nineteen volunteers free from balance issues completed three sessions with varied ankle support: bilateral prophylactic ankle taping, laced bracing device, or barefoot. Each session included an initial balance assessment on the BESS and SOT, a 20 min treadmill walk, and post-walk balance test. Fewer errors, indicating improved balance, were committed on the BESS during the barefoot condition than the braced ankle condition (p = 0.044) at the pre-walk assessment. During the post-walk assessment, fewer errors were committed during the barefoot condition compared to the braced ankle condition (p = 0.034) and the taped ankle condition (p = 0.037). All ankle support conditions showed similar improvements in balance between the pre and post-walk assessments on the BESS (p < 0.001) and SOT composite balance score (p = 0.009). These findings indicate that ankle support devices may influence postural control on the BESS, but not on the NeuroCom SOT. Clinicians using the BESS as a balance assessment device at multiple time points should be consistent in the application of ankle support devices.     

Cognitive loading-induced sway alterations are similar in those with chronic ankle instability and uninjured controls

Performing a cognitive task while balancing can result in either increased or decreased sway depending on the nature of the cognitive task, and is commonly used in pathologic populations to evaluate postural performance. A total of 39 participants were recruited into two groups: uninjured controls (n = 20, age: 21.9 ± 2.1 years, height: 175.0 ± 11.2 cm, mass: 71.3 ± 14.9 kg) and chronic ankle instability (n = 19, age: 22.1 ± 5.6 years, height: 169.7 ± 7.7 cm, mass: 72.9 ± 17.3 kg). Participants were asked to perform one of three cognitive tasks while maintaining single limb balance. Cognitive tasks included backwards counting by 3 (BC), the manikin test (MAN), and random number generation (RNG). Time-to-boundary minima, mean, and standard deviations were calculated and compared between groups as pre to post change scores. Effect sizes and 95% confidence intervals were also calculated to test for group differences and the effect of task performance on sway. No significant main effects of Group or Group by Task interactions were identified (p > 0.05). However, a significant multivariate main effect of Task was identified in BC (p = 0.001, F(6, 32) = 4.804) and RNG (p < 0.001, F(6, 32) = 6.233) but not for MAN (p = 0.117). The results suggest that those with chronic ankle instability and uninjured controls have similar postural–suprapostural interactions across multiple cognitive task domains. Both the BC and RNG tasks resulted in less sway for all participants. Our results suggest that dual-task interference in the CAI population may not be present as previous research would suggest.     

Balance dysfunction in hereditary and spontaneous spastic paraparesis

ObjectiveTo determine how postural sway is affected in people with spastic paraparesis (pwSP) and the impact of different impairments.MethodsIn 20 pwSP and 18 matched healthy controls standing postural sway was measured with eyes open and closed. Vibration threshold, isometric ankle and hip muscle strength and ankle stiffness with the participant at rest or preactivating the muscle was measured.ResultsAntero-posterior (AP) and medio-lateral (ML) sway was higher in pwSP. Muscle strength was reduced and ankle stiffness increased in pwSP. Increased vibratory threshold was seen in 35% of participants. Higher total ankle stiffness (R² = 0.44) was associated with lower AP sway with eyes open whilst hip abductor weakness was associated with increased ML sway with eyes open (R² = 0.36) or closed (R² = 0.47) or AP sway with the eyes closed (R² = 0.48).ConclusionsThe degree of postural sway was related to muscle paresis of the hip abductors particularly in the ML direction and under conditions of reduced sensory input. People with higher total ankle stiffness have less AP sway suggesting that this may help to stabilise the body.     

Effects of passive ankle dorsiflexion stiffness on ankle mechanics during drop landings

ObjectivesVertical landing tasks strain the Achilles tendon and plantar-flexors, increasing acute and overuse strain injury risk. This study aimed to determine how passive ankle dorsiflexion stiffness affected ankle mechanics during single limb drop landings at different vertical descent velocities.DesignCross-sectional study.MethodsPassive ankle dorsiflexion stiffness and passive weight-bearing dorsiflexion range of motion (DROM) were quantified for 42 men. Participants were then grouped as having low (LPS: 0.94 ± 0.15 Nm °^?1; n = 16) or high (HPS: 2.05 ± 0.36 Nm °^?1; n = 16; p < 0.001) passive ankle dorsiflexion stiffness. Three-dimensional ankle joint kinematics was quantified while participants performed drop landings onto a force platform at two vertical descent velocities (slow: 2.25 ± 0.16 m s^?1; fast: 3.21 ± 0.17 m s^?1).ResultsAlthough affected by landing velocity, there were no significant effects of passive ankle dorsiflexion stiffness, nor any significant ankle dorsiflexion stiffness × vertical descent velocity interactions on any outcome variables characterising ankle mechanics during drop landings. Furthermore, there was no significant difference between the groups for passive weight-bearing DROM (LPS: 43.9 ± 4.1°; HPS: 42.5 ± 5.7°), indicating that the results were not confounded by between-group differences in ankle range of motion.ConclusionsNeither high nor low passive ankle dorsiflexion stiffness was found to influence ankle biomechanics during drop landings at different descent velocities. Landing strategies were moderated more by the demands of the task than by passive ankle dorsiflexion stiffness, indicating that passive ankle dorsiflexion stiffness may not affect plantar-flexor strain during a drop landing.     

Altered postural sway persists after anterior cruciate ligament reconstruction and return to sport

Postural sway is defined as the movement of a body's center of mass within the base of support to maintain postural equilibrium. Deficits in postural sway are present after ACL injury; however, current evidence linking it to future injury risk is unclear. The purpose of this study was to determine if postural sway deficits persist after ACL reconstruction (ACLR). The hypothesis tested was that after ACLR, patients who return to sport (RTS) would demonstrate differences in postural sway compared to control (CTRL) subjects. Fifty-six subjects with unilateral ACLR released to RTS, and 42 uninjured CTRL subjects participated. Dynamic postural sway was assessed and 3-way (2 × 2 × 2) ANOVA was used to analyze the variables. A side × group × sex (p = 0.044) interaction in postural sway was observed. A side × group analysis also revealed an interaction (p = 0.04) however, no effect of sex was observed (p = 0.23). Analysis within the ACLR cohort showed less (p = 0.001) postural sway on the involved side (1.82 ± 0.84°) versus the uninvolved side (2.07 ± 0.96°). No side-to-side differences (p = 0.73) were observed in the CTRL group. The involved limb of subjects after ACLR demonstrated the least postural sway. In conclusion, these findings indicate that dynamic postural sway may be significantly altered in a population of athletes after ACLR and RTS compared to CTRL subjects. Further investigation is needed to determine if deficits in postural sway can be used as an effective criterion to assist in the decision to safely RTS after ACLR.     

Reflex ankle stiffness is inversely correlated with natural body sway

We aimed to determine whether effective ankle stiffness (EAS), measured during slow unperceived perturbations of stance, is related to natural anterior–posterior body sway. Because the perturbations are not perceived, any neural component of the response to perturbation is assumed to be “reflex”, in the broad sense of an involuntary response to a stimulus. Subjects stood on a force platform for three 10-min trials. EAS was obtained from the average slope (Δτ/Δα) of the relation between ankle torque (τ) and ankle angle (α), recorded during repeated perturbations delivered at the waist by a weak spring. EAS was normalised using the subject's “load stiffness” (LS), calculated from mass (m) and height (h) above the ankle joint (m·g·h). Sway was obtained from fluctuations in ankle angle prior to perturbation. Variation in EAS and sway between subjects provided spread of data for correlation. There were no significant changes in EAS or sway across trials. All subjects had higher EAS than LS and mean EAS (1124 N m/rad) was significantly greater (p < 0.01) than mean LS (531 N m/rad). There was a strong significant inverse correlation between mean sway and mean normalised EAS (r = −0.68, p = 0.03). We conclude that the body, in response to slow unperceived perturbations, simulates an inverted pendulum with a stiffness of about twice LS and that EAS is largely generated by neural modulation of postural muscles. The inverse correlation between EAS and body sway suggests that the reflex mechanisms responding to perturbation also influence the extent of natural sway.     

Dorsiflexion and dynamic postural control deficits are present in those with chronic ankle instability

ObjectivesTo determine if differences in weight-bearing ankle dorsiflexion range of motion (DFROM) and Star Excursion Balance Test (SEBT) reach distances were present between participants with chronic ankle instability (CAI) and healthy individuals. A secondary objective was to re-examine the relationship between these measures in participants with and without CAI.DesignCase–control.MethodsThirty participants with CAI were matched to 30 healthy participants. All participants performed maximum reach in the anterior, posteromedial and posterolateral directions of the SEBT; as well as, the Weight-Bearing Lunge Test (WBLT) to measure DFROM. Dependent variables included maximal DFROM (cm) and normalized SEBT reach distances (%). Independent t-tests were used for group comparisons (a priori p ≤ 0.05). Simple-linear regression examined the relationship between the WBLT and each SEBT direction.ResultsSignificant differences were detected between groups for the WBLT (CAI: 10.73 ± 3.44 cm, healthy: 12.47 ± 2.51 cm; p = 0.03) and anterior reach distance (CAI: 76.05 ± 6.25%, healthy: 80.12 ± 5.88%; p = 0.01). No differences were identified in posteromedial or posterolateral (ps > 0.70) reach. The WBLT had a significant moderate correlation to anterior reach in both groups (ps < 0.05) but was not significantly correlated to posteromedial or posterolateral reach distance (ps > 0.70).ConclusionsThe results indicate that participants with CAI demonstrated less DFROM and anterior SEBT reach distance compared to health controls. Additionally, both groups demonstrated similar correlations between WBLT and SEBT performance. These findings suggest that participants with CAI have alterations in ankle motion which may negatively influence dynamic postural control; however, the relationship between WBLT and SEBT performance is consistent in those with and without CAI.     

Evidence of sensorimotor deficits in functional ankle instability: A systematic review with meta-analysis

Functional ankle instability (FAI) has been associated with impaired sensorimotor function; however individual studies have produced conflicting results. In an attempt to reduce this ambiguity, a systematic review with meta-analysis was undertaken to determine which sensorimotor deficits exist with FAI. Fifty-three studies assessing sensorimotor factors in subjects with FAI were included from 465 identified articles. Studies were rated for methodological quality and data were pooled for peroneal reaction time, joint position sense, and postural sway during single-leg stance and time to stabilisation from a single-leg jump. Data on joint movement sense were unable to be pooled. When subjects with unstable ankles were compared to healthy controls, sensorimotor impairments were demonstrated for passive joint position sense (mean difference (MD) = 0.7°, 95% confidence interval (CI): 0.2–1.2°, p = 0.004), active joint position sense (MD = 0.6°, 95% CI: 0.2–1.0°, p = 0.002), postural sway in single-leg stance (standardised MD (SMD) = 0.6, 95% CI: 0.2–1.0, p = 0.002), the star excursion balance test (SMD = 0.4, 95% CI: 0.1–0.7, p = 0.009), and time to stabilisation from a single-leg jump in a medio-lateral (MD = 0.6 ms, 95% CI: 0.4–0.8, p < 0.0001) and an antero-posterior direction (MD = 0.7 ms, 95% CI: 0.4–1.0, p < 0.0001). Peroneal reaction time was not affected. Sensorimotor deficits occur for joint position sense and postural control in subjects with FAI. Deficits in peroneal muscle reaction time following perturbation are not evident.     

Functional fatigue of the hip and ankle musculature cause similar alterations in single leg stance postural control

Isokinetic fatigue protocols have been used to determine the relative importance of lower extremity musculature to the maintenance of balance. However, these protocols are not representative of physical activity, thus the recommendations based on these findings may be inappropriate. Therefore, purpose of this investigation was to use a completely within subjects design to examine the effects of a functional ankle and hip fatigue protocol on postural control during single leg stance. All testing was completed in a health and wellness facility where 18 healthy recreationally active university students (nine female, nine male: 21.2 ± 1.96 years, 72.2 ± 17.8 kg, 170.4 ± 10.12 cm) volunteered to participate. Testing consisted of functionally fatiguing the ankle plantar flexors and dorsiflexors as well as the hip flexors and extensors. Postural control was assessed with two pre- and post-fatigue 20 s trials during single leg stance. Three measures of dynamic balance: the overall, medial/lateral, and anterior/posterior stability index were calculated using the Biodex Stability System at stability level 4. Three separate 2-way repeated measure ANOVAs indicated that fatigue of both the ankle (plantar flexors, dorsiflexors) and hip (flexors, extensors) musculature led to postural control impairments for the medial–lateral stability index (p < 0.01), and anterior–posterior stability index (p < 0.01). However, only ankle fatigue resulted in deficits in the overall stability index were (p < 0.01). Furthermore, neither fatigue protocol impaired single leg stance postural control more than the other (p > 0.05). Our results contradict previous isokinetic fatigue protocol findings, which indicate that proximal musculature fatigue results in greater postural control deficits.     

Ankle inversion proprioception measured during landing in individuals with and without chronic ankle instability

BackgroundResearch evidence has suggested that a more sensitive ankle proprioceptive testing method with higher ecological validity is needed for assessing proprioceptive deficits in individuals with chronic ankle instability (CAI).Objectives(1) To determine the test–retest reliability of a novel ankle proprioception assessment tool, the Ankle Inversion Discrimination Apparatus for Landing (AIDAL); (2) To assess whether AIDAL scores were sufficiently sensitive to detect proprioceptive deficits in chronic ankle instability (CAI); and (3) To examine whether AIDAL scores correlated with Cumberland Ankle Instability Tool (CAIT) scores.DesignCross-sectional study.MethodsThe AIDAL was purpose-built to assess ankle discrimination in four positions of ankle inversion (10°, 12°, 14° and 16°) upon landing from a 10 cm drop. Area Under the Receiver Operating Curve (AUC) was employed as the ankle proprioceptive discrimination score. Seven-day test–retest reliability was evaluated with 23 university students (12 CAI and 11 non-CAI), and another 36 university students (18 CAI and 18 non-CAI) were in the comparison study.ResultsThe test–retest reliability ICC score for the whole group was 0.763 (95% CI = 0.519–0.892), which showed an excellent reliability level. ICC _(3,1) was 0.701 for the non-CAI group (95%CI = 0.210–0.910) and 0.804 for the CAI group (95%CI = 0.451–0.939). The CAI group performed at a significantly lower level on the AIDAL assessment than the non-CAI group (0.777 ± 0.05 vs. 0.815 ± 0.05, F = 5.107, p = 0.03). The discriminative AUC value for the AIDAL test was 0.756 with a cut point of 0.819 (sensitivity = 0.733, specificity = 0.800). The MDC₉₀ scores for CAI and non-CAI groups were both 0.04. Spearman's correlation showed that the CAIT scores were significantly correlated with the ankle proprioceptive discrimination scores (rho = 0.401, p = 0.015).ConclusionThe AIDAL showed good test–retest reliability for both non-CAI and CAI groups. Measuring ankle inversion proprioception during landing may be important for assessing the outcomes of CAI rehabilitation, as proprioceptive performance obtained from the AIDAL was significantly correlated with severity of functional ankle instability CAIT scores.     

Ocular dominance and balance performance in healthy adults

PurposeTo evaluate the effect of ocular dominance on balance performance in healthy adult subjects.MethodsOcular dominance was determined in 24 healthy subjects using the hole-in-the-paper test. Balance function was evaluated by computerized dynamic platform posturography (CDPP). Sway index (SI), antero-posterior sway (APS) and lateral sway (LS) were served as outcome parameters.ResultsThe outcome parameters did not differ significantly between dominant and non-dominant eye fixation both in static and angular balance tests (SI—5.47 ± 0.42, 6.23 ± 0.52, p = 0.146 and 18.4 ± 1.07, 19.11 ± 1.15, p = 0.142, respectively; APS—?2.26 ± 4.68, ?5.1 ± 4.6, p = 0.082 and ?1.94 ± 3.33, ?3.64 ± 2.6, p = 0.48, respectively; LS—?1.21 ± 1.46, ?1.12 ± 1.66 p = 0.94 and ?1.98 ± 1.16, ?1.55 ± 1.39, p = 0.69, respectively).ConclusionsOcular dominance does not seem to affect postural function in the monovision and far viewing condition.     

Altered postural control strategies in quiet standing more than 20 years after rupture of the anterior cruciate ligament

AimTo explore long-term consequences of anterior cruciate ligament (ACL) rupture on postural sway and control strategies during bilateral quiet standing, in subjects treated with or without reconstructive surgery compared to uninjured controls.Method70 individuals who had unilateral ACL rupture 23 ± 2.4 years ago (33 received ACL reconstructive surgery, ACL_R, and 37 had physiotherapy only, ACL_PT) and 33 uninjured matched controls (CTRL) (mean age 46 ± 5.3) stood quietly with eyes closed for 3 min on a firm and on a compliant surface, respectively. Center of pressure (CoP) was registered with a force plate and postural sway was calculated from center of mass (CoM) derived from 3D kinematics. Sway density (SD) analyses of CoP assessed distance and duration of stable phases. The torque controlling postural sway was estimated from CoP-CoM.ResultsComparisons across conditions to CTRL revealed larger CoP-CoM-area in ACL_R (p = 0.017, CI: 10.95, 143.10), but not in ACL_PT. Mean distance between SD-peaks was greater for ACL_R (p < 0.001, CI: 1.73, 5.31) than for ACL_PT (p = 0.006, CI: 0.56, 4.12) relative to CTRL. Duration of SD-peaks was smaller for both ACL_R and ACL_PT (p < 0.001, CI: −4.04, −1.23 and −3.82, −1.03, respectively) compared to CTRL. CoM-area in the ACL-groups did not differ from CTRL.ConclusionsACL-injured subjects demonstrated greater postural control efforts than CTRL but without significant differences in postural sway. Control efforts were thus not directly associated with sway and further research should be focused on variance in postural control strategies.     

Effects of Levodopa on Postural Strategies in Parkinson's disease

Altered postural control and balance are major disabling issues of Parkinson's disease (PD). Static and dynamic posturography have provided insight into PD's postural deficits; however, little is known about impairments in postural coordination. We hypothesized that subjects with PD would show more ankle strategy during quiet stance than healthy control subjects, who would include some hip strategy, and this stiffer postural strategy would increase with disease progression.We quantified postural strategy and sway dispersion with inertial sensors (one placed on the shank and one on the posterior trunk at L5 level) while subjects were standing still with their eyes open. A total of 70 subjects with PD, including a mild group (H&Y≤2, N = 33) and a more severe group (H&Y≥3, N = 37), were assessed while OFF and while ON levodopa medication. We also included a healthy control group (N = 21).Results showed an overall preference of ankle strategy in all groups while maintaining balance. Postural strategy was significantly lower ON compared to OFF medication (indicating more hip strategy), but no effect of disease stage was found. Instead, sway dispersion was significantly larger in ON compared to OFF medication, and significantly larger in the more severe PD group compared to the mild. In addition, increased hip strategy during stance was associated with poorer self-perception of balance.     

Bilateral balance impairments after lateral ankle trauma: A systematic review and meta-analysis

Research indicates that balance is impaired in the involved limb following an ankle injury. However, bilateral balance impairments are a viable reason for previous non-significant findings between involved and uninvolved limbs. The purpose of this investigation was to conduct a meta-analysis on studies reporting the effects of lateral ankle trauma on balance of the involved and uninvolved limb after acute ankle injury and chronic ankle instability. Twelve studies qualified for inclusion and assessed static balance for both the involved and uninvolved limbs post-injury and a control group. Meta-analyses calculated standardized mean difference effects and explored moderating variables for the involved and uninvolved limbs relative to controls. A significant cumulative effect size (ES = 0.448, p < 0.00001) indicated that balance of the involved limb is impaired after a history of ankle injury. Moderator variable analysis revealed that both acute (ES = 0.529, p < 0.0002) and chronic (ES = 0.338, p < 0.001) lateral ankle trauma negatively affected balance. Analysis of the uninvolved limb also revealed postural stability impairments (ES = 0.275, p < 0.003). Additional, moderator analysis showed a significant acute effect (ES = 0.564, p < 0.0001), but failed to find significance for individuals with chronic ankle instability (ES = 0.070, p = 0.552). These findings provide strong evidence that balance is bilaterally impaired after an acute lateral ankle sprain. However, these findings suggest that bilateral balance deficits are not present in patients with chronic ankle instability. Based on these findings, the uninvolved limb should not be used as a reference for “normal balance” following an acute lateral ankle sprain. Further, patients with acute lateral ankle sprains should undergo balance training on both limbs.     

The influence of ankle dorsiflexion and self-reported patient outcomes on dynamic postural control in participants with chronic ankle instability

We investigated the influence of ankle dorsiflexion range of motion (DF-ROM) and self-reported patient outcomes on dynamic postural control assessed with the Star Excursion Balance Test (SEBT) in individuals with chronic ankle instability (CAI). Twenty-nine participants with self-reported CAI volunteered. The primary outcome measurements were categorized into clinician-and patient-generated. Clinician-generated outcome measurements included anterior (SEBT-A), posteriormedial (SEBT-PM) and posteriorlateral (SEBT-PL) reach distances (cm) normalized by leg length (cm) of the SEBT, maximum weight-bearing dorsiflexion (WB-DF) (cm), and open-chain DF-ROM (°). Self-reported patient-generated outcome measures included the foot and ankle ability measure and the level of perceived pain, stiffness, stability, and function of their involved ankle on a 10-cm visual analog scale (VAS). Pearson product moment correlations were used to examine the relationship of the SEBT performances with DF-ROM and self-reported patient outcome measures. A multiple linear regression was performed to determine the influence of patient- and clinician-generated measures on the SEBT. SEBT-A performance was significantly and fairly correlated with WB-DF (r = 0.410, p = 0.014), perceived ankle stiffness (r = 0.477, p = 0.014), and open-chain DF-ROM (r = 0.404, p = 0.015). The strongest predictor of the variance in SEBT-A was the combination of the variance in WB-DF and VAS-stiffness (R² = 0.348, p = 0.004). There were no significant correlations with the SEBT-PM and SEBT-PL. WB-DF and VAS-stiffness may represent targets for intervention that need to be addressed to produce the best outcome in participants with CAI when altered dynamic postural control is detected on the SEBT-A.     

Impaired postural control in children with developmental coordination disorder is related to less efficient central as well as peripheral control

BackgroundDevelopmental coordination disorder (DCD) is a neurodevelopmental impairment that affects approximately 6% of children in primary school age. Children with DCD are characterized by impaired postural control. It has yet to be determined what effect peripheral and central neuromuscular control has on their balance control.ObjectiveThe aim of this study was to investigate the underlying mechanisms to impaired postural control in children with DCD using the rambling-trembling decomposition of the center of pressure (CoP).MethodNine children with DCD (9.0 ± 0.5 years, 7 boys, 2 girls) and 10 age- and gender-matched typically developing children (TD) with normal motor proficiency (9.1 ± 0.4 years, 7 boys and 3 girls) performed 3 × 30 s bipedal standing on a force plate in six sensory conditions following the sensory organization procedure. Sway length was measured and rambling-trembling decomposition of CoP was calculated in medio-lateral (ML) and anterior-posterior (AP) direction.ResultsBoth rambling and trembling were larger for the children with DCD in AP (p = 0.031; p = 0.050) and ML direction (p = 0.025; p = 0.007), respectively.ML rambling trajectories did not differ in any conditions with fixed support surface. In ML direction children with DCD had a lower relative contribution of rambling to total sway (p = 0.013).ConclusionThis study showed that impaired postural control in children with DCD is associated with less efficient supraspinal control represented by increased rambling, but also by reduced spinal feedback control or peripheral control manifested as increased trembling.     

Light finger contact concurrently reduces postural sway and enhances signal detection performance in children with developmental coordination disorder

The current study examined the effects of light finger touch on postural sway and signal detection performance in children with developmental coordination disorder (DCD). Children with DCD (n = 30; 18 boys, 12 girls; age = 11.87 ± 0.48 years) and typically developing children (n = 30; 14 boys, 16 girls; age = 11.73 ± 0.52 years) were recruited from schools in Pintung County, Taiwan. Participants completed a signal detection task under no finger touch (NT) and light finger touch (LT) conditions, while postural sway in both anteroposterior (AP) and mediolateral (ML) axes was recorded. In both conditions, children with DCD exhibited significantly higher levels of postural sway (p < 0.05) and lower signal detection performances (p < 0.05) than TDC. Additionally, both groups significantly reduced postural sway (p < 0.05) and enhanced signal detection performance (p < 0.05) when engaged in light finger touch compared with no finger touch. While the effect of LT on postural sway was greater among TDC relative to children with DCD (p < 0.05), the effect of LT on signal detection was greater in children with DCD compared with TDC (p < 0.05). These results suggest that light finger touch is effective in concurrently reducing postural sway and enhancing signal detection in both groups.     

Circadian amplitude and homeostatic buildup rate in postural control

Postural control during quiet stance is a common everyday physical activity. Sleepiness is increasingly prevalent in our 24-h society. Yet, little research exists that quantitatively links the fluctuations in sleepiness and postural control. This study quantifies the circadian amplitude and homeostatic buildup rate in postural control. With a force plate we assessed postural control in 12 participants (21–38 years) every 2 h during 24 h of sustained wakefulness. The sway area was 1.39 ± 0.71 mm² at the circadian high around noon, and 4.02 ± 0.67 mm² at the circadian low around 6 am (a 189% change, p = 0.02). The circadian amplitude of the sway area was therefore 2.63 mm². The sway area was 1.92 ± 0.64 mm² at the start of the 24-h period and 4.42 ± 0.69 mm² at the end of the period (a 130% change, p < 0.001). The homeostatic buildup rate of sway area was 0.04 h^?1. The circadian- and homeostatic effects on sway variability, sway velocity, sway frequency and fractal dimension were smaller but still significant. This study found that the circadian amplitude and homeostatic buildup rate are quantifiable from posturographic data, and that they have significant impact on postural control. This finding is important because it means that one could apply the framework of the famous two-process model of sleep regulation (published by Borbély in 1982) to explain the previously reported sleepiness-related changes in postural control.     

Sensorimotor posture control in the blind: Superior ankle proprioceptive acuity does not compensate for vision loss

To better understand sensorimotor posture control differences between blind and sighted individuals, we examined the role of ankle joint proprioception and ankle muscle strength on postural control in healthy blind (n = 13, 25–58 years) and age- and sex-matched sighted (n = 15, 20–65 years) volunteers. We measured ankle joint proprioceptive acuity and isokinetic muscle strength in plantarflexion and dorsiflexion using an isokinetic dynamometer. We also assessed postural control performance during quiet bipedal stance with and without sudden postural perturbations, and during quiet unipedal stance. We found that while our blind subjects exhibited significantly better proprioceptive acuity than our sighted subjects their postural control performance was significantly poorer than that of the sighted group with eyes open, and no different from that of the sighted group with eyes closed suggesting that their superior proprioceptive acuity does not translate to improved balance control.