Total Sway Area Research Articles

Potential Prodromal Digital Postural Sway Markers for Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) Detected via Dual-Tasking and Sensory Manipulation.

FXTAS is a neurodegenerative disorder occurring in some Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene premutation carriers (PMCs) and is characterized by cerebellar ataxia, tremor, and cognitive deficits that negatively impact balance and gait and increase fall risk. Dual-tasking (DT) cognitive-motor paradigms and challenging balance conditions may have the capacity to reveal markers of FXTAS onset. Our objectives were to determine the impact of dual-tasking and sensory and stance manipulation on balance in FXTAS and potentially detect subtle postural sway deficits in FMR1 PMCs who are asymptomatic for signs of FXTAS on clinical exam. Participants with FXTAS, PMCs without FXTAS, and controls underwent balance testing using an inertial sensor system. Stance, vision, surface stability, and cognitive demand were manipulated in 30 s trials. FXTAS participants had significantly greater total sway area, jerk, and RMS sway than controls under almost all balance conditions but were most impaired in those requiring vestibular control. PMCs without FXTAS had significantly greater RMS sway compared with controls in the feet apart, firm, single task conditions both with eyes open and closed (EC) and the feet together, firm, EC, DT condition. Postural sway deficits in the RMS postural sway variability domain in asymptomatic PMCs might represent prodromal signs of FXTAS. This information may be useful in providing sensitive biomarkers of FXTAS onset and as quantitative balance measures in future interventional trials and longitudinal natural history studies.

Immediate effect of kinesiology taping on muscle strength, static balance and proprioception after eccentric muscle fatigue on ankle: a randomized cross-over trial

BackgroundKinesiology Taping(KT) is commonly used as a physical therapy to prevent exercise-induced fatigue. This study aims to evaluate the immediate effects of KT on muscle strength, static balance, and proprioception after eccentric muscle fatigue on ankle.MethodsTwenty healthy male university students were recruited. The experimental protocol was structured into four sessions, each separated by a one-week washout period to prevent carryover effects. Participants were randomly allocated to one of four intervention conditions in each session, ensuring no participant received the same intervention twice. These conditions were: no taping(NT),sham taping(ST),athletic taping(AT),and kinesiology taping(KT).Taping was applied immediately following an eccentric muscle fatigue protocol targeting the ankle, and assessments were conducted in the order of proprioception, muscle strength and static balance. Isometric muscle strength and proprioception were evaluated using the Biodex isokinetic system. Static balance was measured using the TecnoBody balance platform.ResultsKT had a significantly higher plantarflexion/dorsiflexion peak torque, dorsiflexion average peak torque, and plantarflexion/dorsiflexion average power at 60°/s compared with NT and ST in terms of isometric muscle strength (p < 0.05).Furthermore, the plantarflexion peak torque of KT was significantly greater than AT at 60°/s[p = 0.005,95% confidence interval(CI) = 3.39 to 18.20] and 180°/s[p = 0.006,95%CI(2.62,21.98)]. In terms of proprioception, KT showed a lower absolute error in 25° plantarflexion and 10° dorsiflexion compared to NT, ST and AT. For static balance with eyes-open and eyes-closed conditions, AT and KT had a lower total sway area than NT and ST (p < 0.05). Additionally, a significant difference in total sway length with eyes-open condition was observed between AT and KT[p < 0.001,95%CI(-431.81,-168.25)];total sway area and the center of pressure(COP) velocity in the mediolateral(ML) and anteroposterior(AP) directions with eyes-closed condition were significantly lower in AT compared to KT.ConclusionThis study suggests that KT is more effective than other taping conditions in improving muscle strength and proprioception after eccentric muscle fatigue on ankle. However, AT is more helpful in increasing static postural control ability after ankle muscle fatigue than KT.Trial registrationThis study was registered with www.chictr.org.cn (registration number: ChiCTR2300068278) on 13/2/2023.

Characteristics of static balance performance in 4-stage balance test in the healthy older adults

Background The 4-Stage Balance test is one of the most commonly used tests to assess balance for older adults. Although it is generally accepted that the four positions (including side-by-side (SBSS), semi-tandem (STS), tandem (TS), and single-leg stance (SLS)) in this test are progressively more difficult, there are no studies comparing the balance parameters of the four positions in older adults to prove this result. The purpose of this study is to determine the difficulty of 4 positions in the 4-Stage Balance test and the effect of the dominant and non-dominant lower extremities on static balance among healthy older adults. Methods A total of 115 community-dwelling healthy older adults were included. The postural parameters (including sway range standard deviation (SR), velocity of body sway (V), total sway area (TSA) and sway perimeter (TSP) of the center of pressure) were measured during 8 static postures (including SBSS, left STS, right STS, left TS, right TS, left SLS, right SLS and comfortable stance (CS)). Repeated measures ANOVA was used to analyze the postural parameters in 8 static postures. Results The static balance stability of the five stances in older adults can be ranked in the following sequence: CS > SBSS/STS > TS > SLS. Moreover, changing foot placement in STS, TS and SLS tasks has no influence on stability. This study has been registered in China Clinical Trial Registry (ChiCTR2200065803). Conclusions Our findings suggest that it is feasible to simplify the 4-Stage Balance test to a 3-Stage Balance test in the older adults.

Dual-Task Cost Effects on Static Posture Control Parameters and Choice Reaction Time in Individuals With and Without Intellectual Disabilities.

This study aimed to evaluate the effect of age and intellectual disability (ID) on postural balance parameters, dual-task cost (DTC), and choice reaction time (CRT). Fifty-eight individuals with ID and 55 peers without ID performed a postural stance balance task under two conditions: a single task with eyes open and dual task involving an additional cognitive task (light sequence). Four postural balance parameters (total displacement, total sway area, mediolateral, and anteroposterior dispersion), cost of the dual task ([DTC%] = [(single-task performance - dual-task performance)/single-task performance] × 100), and CRT were recorded, calculated, and analyzed. All postural control parameters reflected poorerperformance during the dual-task condition, nevertheless, DTC was significantly higher only in individuals with ID and only for the total sway area, F(1, 111) = 5.039, p = .027, and mediolateral dispersion, F(1, 111) = 6.576, p = .012. CRT was longer in individuals with ID compared with the individuals without ID, F(1, 111) = 94.979, p ≤ .001, while age did not have a significant effect on the DTC nor on the CRT, F(1, 111) = 0.074, p = .786. In conclusion, an additional cognitive task during the postural balance task had a detrimental effect on various postural balance parameters, leading to increased DTC in terms of total sway area, mediolateral dispersion, and prolonged CRT in individuals with ID.

Verbal Encouragement Provokes Significant Increases in Maximal Volitional Dynamic Postural Sway

Limits of Stability protocols are typically target-oriented, leaving volitional aspects of control unobservable. A novel unconstrained protocol, volitional Limits of Stability (vLOS), shows high test-retest-reliability. We tested if verbal encouragement impacts this protocol. Forty healthy young adults (age 20.1 ± .9 years) performed three trials of vLoS with instructions that were agnostic to strategy or vigor, except trial three included verbal encouragement. Total sway area was used to metric the maximum volitional dynamic sway during each 1-min trial. One-way, repeated-measures ANOVA revealed significant differences (F(2,117) = 41.56, p < 0.0001, η p 2 = 0.52) due to encouragement. Specifically, follow-up paired t-tests showed no difference in sway area between the first two trials (p = 0.61), while trial three was much larger than trials one and two (p < 0.0001). Significant, large increases in sway area with verbal encouragement indicate that top-down mechanisms should be considered in theories of postural control. As well, clinical utilization of novel vLOS should be careful with word selection and delivery of protocol instructions. HIGHLIGHTS Limits of Stability balance tests typically include a goal directed instruction and metrics. Dynamic postural sway should be tested in a task affording participant volitional control. A novel volitional Limits of Stability protocol has been developed. Maximal dynamic postural sway responds to motivating instructions. Psychological factors of postural sway control deserve further investigation.

COVID-19 and postural sway: a comparison of individuals with a SARS-CoV-2 history and healthy sedentary women

Purpose The aim of the study was to evaluate the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postural sway in subjects who have recently recovered from infection. Materials and methods Fifty-six female individuals with a mild to moderate history of SARS-CoV-2 (n = 25, mean age; 21.13 ± 0.64 years) and healthy sedentary controls (n = 31, mean age; 20.09 ± 1.05 years) were included in the study. Postural sway tests were performed in double and single-leg stance on a force plate with eyes open before and after the neuromuscular fatigue test. The Wingate test was used to induce neuromuscular fatigue. To evaluate the change of the variables determined by the measurements of the groups over time and the group-time interactions, a two-way analysis of variance in repeated measures (mixed design repeated measures ANOVA) was used. Results It was found that the SARS-CoV-2 group showed increased total sway path, velocity, and area than those in the healthy group on double and single-leg (right-left) stance (p < 0.05). Conclusions Even if SARS-CoV-2 group individuals have been reported in a mild to moderate outpatient COVID-19 process, they showed deterioration in postural control compared to healthy individuals. In addition, it was found that SARS-CoV-2 accelerated neuromuscular fatigue effects. This can cause more fatigue during activities than individuals who have not had SARS-CoV-2.

IDF21-0192 Preliminary findings of plantar stimulation combined with balance training on postural stability in diabetic neuropathy

Background: Diabetic peripheral neuropathy (DPN) is most common complication seen in the patients with type 2 diabetes mellitus. It is usually reduced sensation of plantar surface of foot. There are evidences demonstrate that patients with type 2 diabetes mellitus with DPN are associated with decline in postural stability in standing and increase risk of falls. Previous studies found that plantar electrical stimulation can improve plantar sensation. Recently, exercise is possibly an alternative intervention to improve balance in the adults. However, balance exercise is inappropriate for patients with type 2 diabetes mellitus with DPN who are impaired plantar sensation and concern about the potential risk of falls. However, no studies have explored whether plantar electrical stimulation combined with standing balance training has positive effects in patients with type 2 diabetes mellitus with DPN. Aim: The purpose of this pilot study was to determine the immediate and long-term effects of 4-week of plantar electrical stimulation combined with standing balance training on postural stability and walking ability in patients with type 2 diabetes mellitus with DP. Method: Four patients with type 2 diabetes mellitus with DPN were participated in this study. Each patient was completed plantar electrical stimulation combined with standing balance training 3 days per week for 4 weeks. Electrical stimulation (biphasic pulse current with a pulse duration of 0.1 ms, 100 Hz) was delivered via two self-adhesive surface electrodes for plantar of feet. The proximal electrode was placed over plantar forefoot area and the distal electrode was placed over plantar heel area. The current intensity was adjusted to produce tingling sensation without any discomfort. During plantar electrical therapy, each patient was performed simultaneously with standing balance training with both feet apart, feet together, tandem standing under eyes open and eyes closed conditions. Postural sway was assessed by total sway area using Lord’s sway meter during standing on 4 sensory conditions (eyes open and closed on a firm surface, eyes open and closed on a foam rubber mat) for 30 seconds of each condition. The walking ability was assessed by 10-meter walk test (10MWT) at preferred speed and maximum speed. All outcome measures were assessed before training, after 4-week training and 2-week follow-up. Results: Four weeks after training, all patients showed decreased total sway area during standing on 4 sensory conditions and increased walking speed on preferred and maximum conditions. Moreover, the results showed a trend toward decreased total sway area during standing on 4 sensory conditions and increased walking speed at 2-week follow-up period. Discussion: The findings from this pilot study showed that the immediate and long-term effects of 4-week of plantar electrical stimulation combined with standing balance training could help to improve postural stability and walking speed in patients with type 2 diabetes mellitus with DPN. This present method might be use as method for improving postural stability and reducing risk of falls in patients with type 2 diabetes mellitus with DPN. However, large sample sizes are still needed to confirm the finding in further study.

Age-Related Changes in Posture Steadiness in the Companion Dog

Aging is associated with changes in the sensory-motor system that could lead to dynamic instability. In fact, postural control deficits have been proposed as an early indicator of frailty. Measurements of the displacement of the center of pressure (COP) using pressure mat data are useful tools to determine postural steadiness. Companion dogs represent a powerful model to study aging in people because they share our environment and experience similar age-related diseases. To date, the effect of aging on postural control in dogs has not yet been evaluated. The aim of this study was to determine the correlation between age and the displacement of the COP in dogs during quiet standing. Due to the diversity of life expectancy in dogs according to their body size, age was normalized as a fraction of the predicted life expectancy. Dogs older than 75% of their life expectancy (n=18) were asked to stand on a pressure mat for 8 seconds per trial during at least five trials. Only the frames where the dogs were standing still and facing forward were analyzed. Age as a fraction of life expectancy was significantly correlated (p<0.05) with the Medio-lateral Range, Root-Mean-Square Distance, 95% Confidence Ellipse, and Total Sway Area of the COP. These results show that, as in humans, aging in dogs is associated with postural control deficits and therefore reinforce the dog as a suitable model for translational studies of aging and postural steadiness.

Quantitative Romberg using a force plate: an objective measure for cervical myelopathy

Surgical decision making for cervical spondylotic myelopathy (CSM) relies on evaluation of symptoms and physical examination. The Romberg test is a clinical exam used to identify balance issues with CSM. However, the Romberg test has a subjective interpretation and has a binary (positive or negative) result. This study aims to compare force plate pressure readings during a standard Romberg test in patients with CSM to age-matched normal healthy volunteers. Prospective cross sectional observational comparative cohort from a single multi-surgeon spine center. Patients who were clinically diagnosed with CSM were compared to age-matched healthy volunteers without a clinical history of spine pathology. Quantitative Romberg Force Plate Measurements METHODS: Patients with CSM requiring surgery and healthy normal volunteers were asked to perform the Romberg test while on a force plate measuring the center of pressure (COP): standing up straight with arms extended for 30 seconds with eyes open, followed by 30 seconds with eyes closed. The change for total sway area, sway frequency and sway speed with eyes closed and eyes open were calculated and compared between patients with CSM and healthy volunteers. Thirty-four CSM patients were age-matched to 34 healthy volunteers. There was a larger change in quantitative Romberg measurements with eyes open versus eyes closed in CSM patients compared to normal volunteers for maximum lateral movement (10.79 cm vs. 0.94 cm, p=.003), maximum anterior-posterior movement (15.06 cm vs. 10.00 cm p=.201), total lateral CoP movement (89.82cm vs. 18.71cm, p=.007), total AP CoP movement (154.68 cm vs. 87.47 cm, p=.601), total CoP trace movement (199.79 cm vs. 88.44 cm, p=.014), sway area (284.74 cm2 vs. 57.76 cm2, p=.006), and average speed (7.00 cm/s vs. 2.91 cm/s, p=.006). Poor standing balance can be quantified in patients with CSM. Quantifying standing balance in patients with CSM shows significantly worse objective measures than age-matched healthy volunteers. The Romberg test on a force plate may help diagnose and evaluate patients with CSM, guide patient management and potentially grade the severity of spinal pathology. Further studies are needed to determine its utility in monitoring disease progression and measure treatment effectiveness.

Normative database of postural sway measures using inertial sensors in typically developing children and young adults.

Reference values utilizing the APDM MobilityLab® inertial sensor system have not been established in children and young adults ages 5-30. These values are necessary for clinicians and researchers to compare to children with balance impairments. A group of 144 typically developing children and young adults from age 5-30 years completed the instrumented SWAY test during 6 test conditions: normal stance, firm surface, eyes open (EO) and closed (EC); normal stance, foam surface, EO and EC; and tandem stance, firm surface, EO and EC. Selected variables for normative outcomes included total sway area, and the mean, sagittal and coronal values for RMS sway, jerk, sway velocity and path length. Sex differences were examined within age groups via t tests. The effect of age on postural sway variables was analyzed using a one-way ANOVA for the mean values of total sway area, RMS sway, velocity and jerk, followed by post-hoc pairwise comparisons. All sway parameters decreased significantly with age (p < 0.0001). Adult-like total sway area and jerk were achieved by ages 9-10 except for jerk during EC on foam. RMS sway and sway velocity reached adult levels by ages 11-13 during all EO and tandem stance conditions, and 14-21 with EC during normal stance on firm and foam surfaces for RMS sway and EC on firm surfaces for velocity. Females ages 5-6 performed more poorly during EO firm and EC foam for certain variables, but better during EO tandem and females ages 7-13 outperformed males when sex differences were found. These reference values can now be used by clinicians and researchers to evaluate abnormal postural sway and response to interventions in children and young adults.

101. Quantitative Romberg using a force plate: An objective measure for cervical myelopathy

<h3>BACKGROUND CONTEXT</h3> Surgical decision-making for cervical spondylotic myelopathy (CSM) relies on evaluation of symptoms and physical examination. The Romberg test is a clinical exam used to identify balance issues with CSM. However, the Romberg test has a subjective interpretation and has a binary (positive or negative) result. While previous studies showed that force plate pressure readings provide quantitative measurements that objectively identify poor postural control in patients with CSM, the study compared an older CSM patient cohort with a significantly younger normal cohort, failing to account for regular aging changes. <h3>PURPOSE</h3> This study aims to compare force plate pressure readings during a standard Romberg test in patients with CSM to age-matched normal healthy volunteers. <h3>STUDY DESIGN/SETTING</h3> Longitudinal observational comparative cohort from a single multisurgeon spine center. <h3>PATIENT SAMPLE</h3> Patients who were clinically diagnosed with CSM (mean age 54.8 years, N=27) were compared to age-matched healthy volunteers (mean age 54.4 years, N=27) without a clinical history of cervical pathology. <h3>OUTCOME MEASURES</h3> Quantitative Romberg Force Plate Measurements. <h3>METHODS</h3> Patients with CSM requiring surgery and healthy normal volunteers were asked to perform the Romberg test while on a force plate measuring the center of pressure (COP): standing up straight with arms extended for 30 seconds with eyes open, followed by 30 seconds with eyes closed. The change for sway area, sway frequency and sway speed with eyes closed and eyes open were calculated and compared between patients with CSM and healthy volunteers. <h3>RESULTS</h3> Twenty-seven of 48 CSM patients were age-matched to 27 healthy volunteers. There was a larger change in Romberg measurements with eyes open vs eyes closed in CSM patients compared to normal volunteers for maximum lateral movement (12.1mm2 vs 4.1mm2, p<0.01), total lateral COP movement (97.2mm2 vs 32.6mm2 p<0.02), Total AP COP movement (165.8mm2 vs 78.1mm2, p<0.01), COP trace movement (211.5mm2 vs 87.8mm2, p<0.01), and total sway area (365.4mm2 vs 62.1mm2, p<0.01). Change in average speed with eyes open and eyes closed (7.0m/s vs 4.2m/s, p<0.09) and Anteroposterior movement (19.0 mm2 vs 10.8 mm2, p<0.07) were similar between the two groups. <h3>CONCLUSIONS</h3> Poor standing balance can be quantified in patients with CSM. Quantifying standing balance in patients with CSM shows significantly worse objective measures than age-matched healthy volunteers. The Romberg test on a force plate may help diagnose and evaluate patients with CSM, guide patient management, potentially grade the severity of spinal pathology, allow more timely surgical intervention, and improve surgical outcomes. Further studies are needed to determine its utility in monitoring disease progression and measure treatment effectiveness. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Force Platform Assessment of Postural Balance in Knee Osteoarthritis - A Systematic Review

Osteoarthritis (OA) is the most common form of progressive joint disease. It presents with pain, stiffness and swelling which leads to muscle weakness and reduced physical function. The involvement of lower limb joints leads to deterioration of proprioception and predisposes to postural instability. Postural sway assessment is an integral component in the institution of goal-oriented treatment for OA. Postural sway assessment consists of various parameters such as Antero-Posterior amplitude, Medio-Lateral amplitude, total sway area, and Center of Pressure velocity. The study aims to systematically appraise the current evidence of different postural sway parameters from force plates and their association with knee OA. A literature search was conducted through PubMed, Scopus, and Web of Science databases. 115 articles were identified for screening, of which 10 studies met the inclusion criteria. The methodological quality of the study was assessed by two independent reviewers using Newcastle-Ottawa Quality Assessment Scale (NOS). 5 out of 9 studies showed significant Anterior-Posterior deviation, 5 out of 6 studies showed significant Center of pressure deviation and 3 out of 9 studies showed significant Medio- Lateral deviation. This review indicates that patients with knee OA sway more in Anterior-Posterior direction as compared to Medio-Lateral direction and can be considered as a key finding while assessing knee pain.

The Impact of a High/Low Fulcrum Rotating Balance Platform on Standing Postural Stability in Healthy Young Adults

Back or lower limb pathology may interfere with standing balance. Knowing the impact of high and low fulcrum balance platforms on tracking rotational activities could tailor stability training interventions. Purpose: To determine the influence of a low and high fulcrum balance platform combined with tracking tasks on postural sway while standing. Method: Twenty-five participants performed seven activities at two difficulty levels. The total sway area and medial-lateral (ML) and anterior-posterior (AP) sway direction, velocity, and distance were measured during balance activities with various tracking platforms with a fixed middle fulcrum. Results: MANOVA revealed that postural sway area (m^2/s^4) with a high fulcrum decreased in front to back, rear twist, and front twist (p = 0.05) balance activities. The Mean velocity (m/s) analysis showed that tasks with a high fulcrum elicited slower velocities in the ML direction than those with low fulcrum activity (p

Does Balance Fluctuates Depending on Leg Dominance? A Cross-sectional Study

Falls due to altered balance are a worldwide health issue. Various components are involved in maintaining postural stability, such as the base of support, integration of sensory information, and the ability of the body to adapt to perturbations. Understanding balance strategies and components is imperative for rehabilitation when stability is affected. Purpose: This study aimed to characterize the balance distinction between left and right leg dominance and identify postural adaptations during left and right rotations in young healthy adults. Method: This study assessed single-leg stance on a firm surface, clockwise (right), and counterclockwise (left) rotation on a balance board with a fixed middle fulcrum on 70 health young adults participants, 7 males and 63 females aged 25 ± 4.66 SD (37 left leg dominant and 32 right leg dominant). Accelerometer and gyroscope sensors were used to capture the total sway area, medial-lateral (ML) and anterior-posterior (AP) directions, velocities, and distances. Results: The MANOVA revealed similarities in the left and right single stance balance. The comparison of clockwise rotations versus counterclockwise rotations showed a significant increase in sway and distance in the anteroposterior (AP) direction while rotating towards the left or CCW (P&lt;0.05). The comparison of right-leg dominant versus left-leg dominant during CW rotation revealed a significantly increased sway and distance of sway in the ML direction (P&lt;0.05) for individuals with right-leg dominance when compared to their left-leg dominant counterparts during CW rotations. Conclusion: The current study found distinctions in balance adaptation or changes within the central nervous system to compensate for an increase in sway during counterclockwise rotation. Furthermore, individuals with right leg dominance had increased difficulty in maintaining stable sway during clockwise rotational movements. Clinicians should consider examining rotational adaptations or one’s ability to make alterations within the central nervous system during rotational movements to maintain the center of mass within the base of support in balance activities which compromise postural control.

Assessment of standing balance in normal versus cervical spondylotic myelopathy patients

BackgroundThe Romberg test is used to identify balance issues in patients with Cervical Spondylotic Myelopathy (CSM), but has subjective interpretation. The purpose of this study is to evaluate force plate pressure readings during a Romberg test to quantify postural control. MethodsQuantitative Romberg force plate readings with eyes open and closed in patients with CSM were obtained and changes in balance measurements were compared to a normal population (N = 28, mean age 39 ± 7 years). ResultsWe identified 30 CSM patients with a mean age of 58 ± 10 years. Majority of patients presented with pain (90%) and neurologic symptoms (83%). Cord compression on imaging was identified in 90%. Mean eyes closed Romberg measurements were larger compared to eyes open measurements in CSM patients (p < 0.01). There was a larger change in Romberg (∆R) measurements in CSM compared to normals for total sway area (TSA, 14.18 vs 0.02 cm2, p < 0.001) and average speed (AS, 2.07 vs 0.23 cm/s, p < 0.001). The presence of long tract signs produced larger ∆R (TSA, 15.35 vs 0.02 cm2, p = 0.003; AS, 2.21 vs 0.23 cm/s, p = 0.001), and those with identified cord compression on imaging also had larger ∆R (TSA, 15.1 vs 0.02 cm2, p < 0.001; AS, 2.17 vs 0.23 cm/s, p < 0.001). ConclusionsStanding balance can be quantified in patients with CSM and is worse when compared to a normal population. Long tract signs and cord compression in imaging translates to worse balance in myelopathic patients. The use of quantitative Romberg measurements help evaluate balance in CSM.

P35. Quantitative Romberg using a force plate: an objective measure for cervical myelopathy

BACKGROUND CONTEXT Surgical decision making for cervical spondylotic myelopathy (CSM) relies on symptoms and physical examination. The Romberg test is a clinical exam used to identify balance issues with CSM, but has subjective interpretation and has a binary (positive or negative) result. Using a force plate, the area, frequency and speed of sway with eyes open and eyes closed can be quantified. This objective measurement has the potential for earlier intervention and/or to monitor treatment progress. Additionally, this measurement tool is more practical than a formal gait analysis in the clinical setting. PURPOSE To determine if a quantitative Romberg test can provide an objective measure of poor standing balance due to myelopathy. STUDY DESIGN/SETTING Age-matched prospective observational comparative cohort. PATIENT SAMPLE Patients with CSM requiring surgery and healthy normal volunteers. OUTCOME MEASURES Total sway area (TSA), sway frequency and sway speed. METHODS Patients with CSM requiring surgery and healthy normal volunteers were asked to perform the Romberg test while on a force plate measuring the center of pressure: standing up straight with arms extended for 30 seconds with eyes open, followed by 30 seconds with eyes closed. The change in total sway area (TSA), sway frequency and sway speed with eyes closed and eyes open were calculated. RESULTS A total of 27 of 48 CSM patients were age-matched to 27 healthy volunteers with a mean age of 54 years. The change in TSA (211.5mm2), frequency (365.4/s) and speed (7.0m/s) was statistically greater in the CSM group compared to normal TSA (87.8mm2, p=0.005), frequency (62.1/s, p=0.008) and speed (4.2m/s, p=0.085). CONCLUSIONS Poor standing balance can be quantified in patients with CSM. The Romberg test on a force plate may help diagnose and evaluate CSM. Further studies are needed to determine its utility to measure treatment effectiveness. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Sound Effects on Standing Postural Strategies in the Elderly via Frequency Analysis Approach

Sound and sound frequency could improve postural sway in the elderly. The power spectrum intervals of the center of pressure (COP) displacement are associated with different postural regulations, which could be revealed by frequency analysis. The aim of the study was to investigate the effects of sound on dual-tasking postural control and conduct frequency analysis to distinguish postural regulations in the elderly. Fifteen young and 15 older healthy participants were instructed to stand on a force platform and performed the Purdue Pegboard test while hearing 50 dB sounds with sound frequencies of 250 Hz, 1000 Hz, 4000 Hz, or no sound. The total excursion, velocity, sway area, and power spectrum of low-, medium-, and high-frequency bands of the COP displacement were calculated in the anterior–posterior and medial–lateral directions. The percentages of low-frequency and medium-frequency bands in both directions were significantly different between with and without sound conditions, but not affected by sound frequency. Older adults showed a smaller percentage of low-frequency, larger percentage of medium-frequency, larger total COP excursion, and faster velocity in the medial–lateral direction. The outcome of the study supports the frequency analysis approach in evaluating sound effects on postural strategies in dual-tasking and reveals older adults utilize vestibular regulation as the primary postural strategy when the dual-task required visual attention.

The Effects of Dual-Task Cognitive Interference and Environmental Challenges on Balance in Huntington's Disease.

Huntington's disease (HD) is characterized by chorea, balance and gait impairments, and cognitive deficits, which increase fall risk. Dual task (DT) and environmentally challenging paradigms reflect balance related to everyday life. Furthermore, the impact of cognitive deficits on balance dysfunction and falls in HD is unknown. To determine the impact of DT interference, sensory feedback, and cognitive performance on balance and falls in HD. Seventeen participants with HD (55 ± 9.7 years) and 17 age-matched controls (56.5 ± 9.3 years) underwent quantitative balance testing with APDM inertial sensors. Postural sway was assessed during conditions of manipulated stance, vision, proprioception, and cognitive demand. The DT was a concurrent verbal fluency task. Neuropsychological assessments testing multiple cognitive domains were also administered. HD participants exhibited significantly greater total sway area, jerk, and variability under single-task (ST) and DT conditions compared to controls (P = 0.0002 - < 0.0001). They also demonstrated greater DT interference with vision removed for total sway area (P = 0.01) and variability (P = 0.02). Significantly worse postural control was observed in HD with vision removed and reduced proprioception (P = 0.001 - 0.01). Decreased visuospatial performance correlated with greater total sway and jerk (P = 0.01; 0.009). No balance parameters correlated with retrospective falls in HD. HD participants have worse postural control under DT, limited proprioception/vision, and greater DT interference with a narrowed base and no visual input. These findings may have implications for designing motor and cognitive strategies to improve balance in HD.

Kinematic analysis of dance-based exergaming: effect of song pace on center of mass and joint mobility.

[Purpose] To establish a quantitative kinematic assessment method for examining postural stability and physical mobility during dance-based exergaming. [Participants and Methods] Fifteen young adults participated in one session of dance-based exergaming assessment using segments from Kinect ‘Just Dance 3’ consisting of slow-, medium-, and fast-paced songs. A motion capture system was used to record full body kinematics, and a customized MATLAB code was used to compute the variables of interest, such as center of mass sway area, excursion, and peaks, as well as step count and joint excursions. [Results] Total center of mass sway area and excursion were significantly greater for slow-paced (total sway area=1,077.6 ± 209.9 cm2; total excursion=629.8 ± 380.5 cm) and fast-paced (total sway area=314.1 ± 133.6 cm2; total excursion=478.5 ± 149.0 cm) songs than for the medium-paced song (total sway area=212.9 ± 346.0 cm2; total excursion=311.2 ± 119.5 cm). Joint excursion was greater for the knee (ranging from: (slow to fast-paced songs: 55.5°–83.1°) and hip (slow to fast-paced: 40.6°–50.4°) than for the ankle (slow to fast-paced: 32.2°–46.7°) for all three dance paces. Additionally, step count was significantly, positively correlated with song pace (r=0.52). [Conclusion] The current study was able to quantify and provide normative values for postural control and joint mobility among healthy young adults during dance-based exergaming with 3 hip-hop songs of different paces from the Microsoft Kinect ‘Just Dance 3’. The results indicated that different paces (intensities) of dance songs corresponded to distinct movement kinematic trends, particularly with slow-paced song having the maximum center of mass excursion and lowest joint excursion, while fast-paced song exhibits the reverse, along with medium-paced song exhibiting the highest hip and ankle joint angle excursions, while the fast-paced song had increased knee joint angle excursions.

Inflection points in longitudinal models: Tracking recovery and return to play following concussion.

The return to play (RTP) process may occur during longitudinal studies tracking recovery after concussion. This factor, which is often omitted within statistical designs, could affect the fit and overall interpretation of the statistical model. This article demonstrates the difference in results and interpretation between 2 linear mixed-model designs: (1) a between-group longitudinal (GROUP) analysis and (2) a between-group longitudinal model that used an inflection point to account for changes around the time of RTP (RTP analysis). These analyses were conducted on instrumented balance data collected on 23 concussed athletes and 25 controls over 8weeks following concussion. Total sway area and the range of mediolateral acceleration were used as outcome measures. No significant findings were found in the GROUP design for either outcome measure. In contrast, the RTP analysis revealed significant effects of time (P=.007) and RTP change (P=.007), and group*time (P=.028) and group*RTP change (P=.022) interactions for total sway area, and effects of group (P=.011), time (P=.010), and RTP change (P=.014), and group*time (P = .013) and group*RTP change interactions (P=.013) for range of mediolateral acceleration. For both outcomes, the RTP model fit the data significantly better on comparison of likelihood ratios (P≤.027). These results suggest that allowing for an inflection point in the statistical design may assist understanding of what happens around clinically meaningful time points. The choice of statistical model had a considerable effect on the interpretation of findings, and provokes discussion around the best method for analyzing longitudinal datasets when important clinical time points like RTP exist.