Equilibrium Scores Research Articles

Investigation of Balance Function Using Dynamic Posturography under Electrical-Acoustic Stimulation in Cochlear Implant Recipients

Introduction. The purpose of the present study is to investigate the effect of electrical-acoustic stimulation on vestibular function in CI patients by using the EquiTest and to help answer the question of whether electrically stimulating the inner ear using a cochlear implant influences the balance system in any way. Material and Methods. A test population (n = 50) was selected at random from among the cochlear implant recipients. Dynamic posturography (using the EquiTest) was performed with the device switched off an switched on. Results. In summary, it can be said that an activated cochlear implant affects the function of the vestibular system and may, to an extent, even lead to a stabilization of balance function under the static conditions of dynamic posturography, but nevertheless also to a significant destabilization. Significant improvements in vestibular function were seen mainly in equilibrium scores under conditions 4 and 5, the composite equilibrium score, and the vestibular components as revealed by sensory analysis. Conclusions. Only under the static conditions are significantly poorer scores achieved when stimulation is applied. It may be that the explanation for any symptoms of dizziness lies precisely in the fact that they occur in supposedly noncritical situations, since, when the cochlear implant makes increased demands on the balance system, induced disturbances can be centrally suppressed.

Variations in Linear and Nonlinear Postural Measurements under Achilles Tendon Vibration and Unstable Support-Surface Conditions

ABSTRACT Reduced support-surface stability has been shown to attenuate the effect of Achilles tendon vibration on backward body displacement. In the present study, 20 participants performed a quiet, upright standing task on a stable and sway-referenced support, with and without vibration. The authors calculated equilibrium scores (ES), approximate entropy (ApEn), and mean and peak power spectral density frequencies of center-of-pressure variations. It was found that ES values decreased with the addition of vibration and in the sway-referenced support condition. ApEn values decreased with the addition of vibration but only with a stable support. Conversely, mean and peak frequencies increased with the addition of vibration, independent of support stability. These results suggest that the role of ankle proprioceptive input changes depending on support-surface characteristics and demonstrate the value of using both linear and nonlinear measures of postural sway.

Vestibulo-Ocular Reflex and Balance Maturation in Healthy Children Aged from Six to Twelve Years

Objectives: Because both the vestibulo-ocular and vestibulospinal pathways depend on neurological maturation during childhood, the purpose of this study was to evaluate the vestibulo-ocular reflexes (VOR) and balance parameters of children aged from 6 to 12 years. Methods: 147 healthy children were included in the study. The visual vestibulo-ocular reflex (VVOR) and VOR were recorded during sinusoidal rotation (videonystagmography), with calculation of the gain. The sensory organization on postural control was studied using computerized dynamic posturography (EquiTest®), with equilibrium scores (ES) and sensory organization tests. Results: Data were analyzed according to age groups: group a from 6 to 8 years, group b from 9 to 10 years, and group c from 11 to 12 years. Whereas VVOR gain was comparable in the three groups, VOR gain was lower in groups b and c compared to group a. Global ES increased with age. Analyzing each sensory component for postural control, the only score that increases with age is the vestibular one. Somesthetic and visual scores remained comparable in the three groups. Conclusions: Our results in a large cohort of children confirm previous ones: VOR gain is higher in young children, whereas ES is lower. Moreover, it seems that the 10- to 12-year-old children use their vestibular inputs more compared to younger ones. From these results it can be suggested that both the vestibulo-ocular and vestibulospinal pathways are still maturing between 6 and 12 years.

Postural Responses to Dynamic Perturbations in Amputee Fallers Versus Nonfallers: A Comparative Study With Able-Bodied Subjects

Vanicek N, Strike S, McNaughton L, Polman R. Postural responses to dynamic perturbations in amputee fallers versus nonfallers: a comparative study with able-bodied subjects. Objectives To quantify postural responses in amputee fallers versus nonfallers by using computerized dynamic posturography. Design All participants completed standard protocols on the Sensory Organization Test (SOT) and Motor Control Test (MCT) of the NeuroCom Equitest. Setting Human performance laboratory in a university in the United Kingdom. Participants Transtibial amputees (n=9) and able-bodied subjects (n=9) (all categorized into fallers and nonfallers according to their falls history in the previous 9mo). Interventions Not applicable. Main Outcome Measures Equilibrium and strategy scores on the SOT. Postural response latency and weight distribution on the MCT. Results Equilibrium scores were highest when somatosensory information was accurate, but there were no differences between the groups. Strategy scores were lower when visual cues and somatosensory information were inaccurate, and the fallers and nonfallers used a combination of ankle and hip strategies to prevent a loss of balance. The amputee nonfallers indicated they had a greater reliance on visual input even when it was inaccurate compared with the amputee fallers, whereas the control fallers used the hip strategy significantly more compared with the control nonfallers (SOT condition 6: 56±22 vs 72±10, P=.01). Weight distribution symmetry showed that the amputee nonfallers bore significantly more weight through their intact limb compared with the amputee fallers during backward and forward translations ( P<.05). Conclusions The SOT and MCT appeared to be population specific and therefore did not reliably identify fallers among transtibial amputees or distinguish between community-dwelling control fallers and nonfallers. Amputee and control fallers can prevent a fall during challenging static and dynamic conditions by adapting their neuromuscular responses. The results from this study have important implications for amputee gait rehabilitation, falls prevention, and treatment programs.

Children with Attention Deficit Hyperactivity Disorder Have Impaired Balance Function: Involvement of Somatosensory, Visual, and Vestibular Systems

To compare standing balance performance and sensory organization of balance control in children with attention deficit hyperactivity disorder (combined type) (ADHD-C) and typically developing children. School-aged children (n = 43) with ADHD-C and 50 age- and sex-matched typically developing children participated in the study. Sensory organization of standing balance was evaluated using the Sensory Organization Test (SOT). In addition to the composite equilibrium score, somatosensory, vestibular, and visual ratios, which were indicators of the ability of the child to use information from the respective sensory systems to maintain balance, were computed. Multivariate analysis of covariance (MANCOVA) was used to compare the outcome variables between the 2 groups while controlling for physical activity level. MANCOVA revealed that children with ADHD-C had significantly lower composite equilibrium scores (P < .001) and somatosensory (P = .029), vestibular (P = .037), and visual ratios (P = .001) than control children, by 10.3%, 2.1%, 15.6%, and 16.0%, respectively. Children with ADHD-C had significant deficits in standing balance performance in all conditions that included a disruption of sensory signals. The visual system tends to be more involved in contributing to the balance deficits in children with ADHD-C than the somatosensory and vestibular systems.

Balance Performance In Middle-aged Subjects With Cervical Spondylosis

Cervical spondylosis is a common progressive disorder in aging cervical spine. Sensory systems are important for balance maintenance. Poor postural control in older people is associated with increased risk of falling. PURPOSE: This study was to evaluate the impact of cervical spondylosis in the middle-aged group, compared with the young control group, on balance performance, neck range of motion (ROM) and isometric muscle strength. METHODS: Fifteen middle-aged subjects (age: 52±7years) with cervical spondylosis, diagnosed by cervical spine radiographs, and fifteen young subjects (age: 22±2years) underwent sensory organization test (SOT) using SMART Balance Master System. SOT evaluates postural control under 6 conditions including (1) eyes open and fixed support (EO); (2) eyes closed and fixed support (EC); (3) sway-referenced vision and fixed support (SV); (4) eyes open and sway-referenced support (SS); (5) eyes closed and sway-referenced support (ECSS); and (6) sway-referenced vision and support (SVSS). Microfet3 was used to assess neck ROM and isometric strength. Comparisons between groups were made using independent t-test. RESULTS: Equilibrium scores showed significant differences between groups in EO (94.4±1.7 vs. 95.9±1.0), SS (80.1±15.5 vs. 91.2±2.6), ECSS (57.0±16.4 vs. 70.6±4.9) and SVSS (59.7±15.1 vs. 78.7±6.3). Vis (0.8±0.2 vs. 1.0±0.02) and Vest (0.6±0.2 vs. 0.7±0.1) ratios had significant differences between groups. Neck ROM was significantly larger and isometric rotational muscle strength was also significantly stronger in the young group than the middle-aged group. CONCLUSION: Cervical spondylosis was diagnosed in the milled-aged group and might contribute to the change of neck ROM and isometric strength. ROM and strength were both deteriorated in the middle-aged group compared to the young group. Sensory ratios indicate the ability to use the visual or vestibular system and reflect in a sense the neck function. Poor balance performance in the middle-aged group may be in part attributed to poor neck function, reflected in the lower sensory ratios.

Test Order Effects of Computerized Dynamic Posturography and Calorics

To determine whether there is a test order effect of the caloric subtest of videonystagmography on the Sensory Organization Test (SOT) of computerized dynamic posturography, and to assess the learning effect of multiple posturography test sessions on the SOT score. Scores on the 6 SOT conditions before and after caloric testing were compared for 10 participants age 18-36 years. Four SOT sessions were completed prior to caloric testing to assess the presence of a learning effect and establish precaloric baseline SOT scores. All participants had normal vestibular systems with no history of dizziness or imbalance. Caloric testing had a significant effect on the equilibrium score for only 1 of 6 test conditions. While meeting statistical significance, the actual change in score for this condition was very small. Equilibrium scores improved for the more difficult test conditions between the 1st and 2nd SOT sessions. Results indicate that there are minimal test order effects of calorics on the SOT. Results confirm that a significant improvement in score for more challenging test conditions occurs between SOT Sessions 1 and 2 as a result of learning. Therefore, clinicians must be cautious when using posturography to monitor patient improvement.

The Effect of a Senior Jazz Dance Class on Static Balance in Healthy Women Over 50 Years of Age: A Pilot Study

The purpose of this pilot study is to assess the impact of a senior jazz dance class on static balance for healthy women over 50 years of age using the NeuroCom Smart Balance Master System (Balance Master). A total of 12 healthy women aged 54-88 years completed a 15-week jazz dance class which they attended 1 time per week for 90 min per class. Balance data were collected using the Sensory Organization Test (SOT) at baseline (pre), at 7 weeks (mid), and after 15 weeks (post). An equilibrium score measuring postural sway was calculated for each of six different conditions. The composite equilibrium score (all six conditions integrated to 1 score) was used as an overall measure of balance. Repeated measures analyses of variance (ANOVAs) were used to compare the means of each participant's SOT composite equilibrium score in addition to the equilibrium score for each individual condition (1-6) across the 3 time points (pre, mid, post). There was a statistically significant difference among the means, p < .0005. Pairwise (Bonferroni) post hoc analyses revealed the following statistically significant findings for SOT composite equilibrium scores for the pre (67.33 + 10.43), mid (75.25 + 6.97), and post (79.00 + 4.97) measurements: premid (p = .008); prepost (p < .0005); midpost (p = .033). In addition, correlational statistics were used to determine any relationship between SOT scores and age. Results indicated that administration of a 15-week jazz dance class 1 time per week was beneficial in improving static balance as measured by the Balance Master SOT.

BALANCE DEFICITS AFTER SPORTS-RELATED CONCUSSION IN INDIVIDUALS REPORTING POSTTRAUMATIC HEADACHE

Posttraumatic headache (PTH) may affect neurocognition after sports-related concussion. To our knowledge, no studies have examined how PTH affects balance after concussion using dynamic posturography. The purpose of this study is to compare balance after concussion between athletes reporting PTH and athletes not reporting PTH. We conducted a retrospective, repeated-measures design with participants grouped by presence of postinjury report of headache. Balance testing was conducted on 108 concussed collegiate athletes (age, 18.83 +/- 1.27 yr; height, 180.92 +/- 10.01 cm; mass, 83.29 +/- 19.62 kg). Presence of PTH during the first postinjury test session (group) and test time (baseline, postinjury) served as the independent variables. The composite equilibrium score and the somatosensory, vestibular, and visual ratio scores served as dependent variables. A 2 x 2 mixed model analysis of variance was used to analyze each outcome measure. Significant decreases in all four measures assessed were noted after concussion compared with preseason baseline measures (P < 0.05). Significant group by test-time interactions were observed, suggesting that composite equilibrium (F1106 = 6.6089; P = 0.012) and vestibular ratio (F1106 = 7.156; P = 0.009) scores are affected by the presence of PTH. Athletes reporting PTH also demonstrated worse visual ratio scores compared with individuals not experiencing PTH (F1106 = 4.26; P = 0.041). No other significant findings were observed for the somatosensory ratio score. Current literature proposes that PTH is associated with cognitive deficits. Our study indicates that PTH may also contribute to increased balance deficits. We believe the deficits may be a result of increased sensory organization challenges after injury. Clinicians should be mindful of these findings when managing concussed athletes reporting headache.

Measurement of balance in computer posturography: Comparison of methods—A brief review

Some symptoms related to disequilibrium may not be detected by a clinical exam. Therefore, objective study is important in assessing balance. In this paper, methods to measure balance in computer posturography are compared. Center of pressure (COP) displacement, equilibrium score (ES) and postural stability index (PSI), the main measures of assessing balance are described and their merits and disadvantages are discussed. Clinicians should apply that measure which suits the specific strategies in a specific situation. Measuring devices such as Force plate, Balance Master and Equitest are also discussed. Although the Balance Master and Equitest devices are more costly compared to the force plate only, they are more useful for assessing balance relevant to daily life activities that might result in falls.

Effects of Dynamic Head Tilts on Sensory Organization Test Performance: A Comparison Between College-Age Athletes and Nonathletes

Controlled laboratory study. To compare postural performance measures of athletes with those of nonathletes when completing the standard Sensory Organization Test (SOT) and a modified SOT that included dynamic head tilts (DHT-SOT). Authors of recently published research have suggested that modifications to the SOT protocol (eg, introduction of pitch and roll head tilts) may enhance the test's sensitivity when assessing postural stability in individuals with higher balance capabilities or with well-compensated sensory deficits. Nineteen athletes and 19 nonathletes (group) completed both the SOT and DHT-SOT (protocol). During the SOT, participants stood upright as steadily as possible for 20 seconds during each of 6 different sensory conditions. As a variation of the SOT, the DHT-SOT incorporated active pitch and roll head tilts into the SOT protocol. Four 2-way mixed-model analyses of variance (with protocol as the repeated factor) were performed to determine if the composite equilibrium score or the visual, vestibular, or somatosensory ratio scores differed between the 2 groups across the 2 testing protocols. Significant group-by-protocol interaction effects were present for both the composite equilibrium score and visual ratio. Follow-up simple main-effects analyses indicated that these measures did not differ between groups for the SOT protocol but were significantly different on the DHT-SOT. The addition of dynamic head tilts to the SOT protocol resulted in subtle differences in balance function between athletes and nonathletes. Athletes demonstrated an increased ability to adapt to sensory disruptions during the DHT-SOT. Therapists should consider including active pitch and roll head tilts to the SOT when evaluating individuals with higher balance function or to detect subtle deficits in balance function. Diagnosis, level 3b.

Approximate entropy detects the effect of a secondary cognitive task on postural control in healthy young adults: a methodological report.

BackgroundBiomechanical measures of postural stability, while generally useful in neuroscience and physical rehabilitation research, may be limited in their ability to detect more subtle influences of attention on postural control. Approximate entropy (ApEn), a regularity statistic from nonlinear dynamics, recently has demonstrated relatively good measurement precision and shown promise for detecting subtle change in postural control after cerebral concussion. Our purpose was to further explore the responsiveness of ApEn by using it to evaluate the immediate, short-term effect of secondary cognitive task performance on postural control in healthy, young adults.MethodsThirty healthy, young adults performed a modified version of the Sensory Organization Test featuring single (posture only) and dual (posture plus cognitive) task trials. ApEn values, root mean square (RMS) displacement, and equilibrium scores (ES) were calculated from anterior-posterior (AP) and medial-lateral (ML) center of pressure (COP) component time series. For each sensory condition, we compared the ability of the postural control parameters to detect an effect of cognitive task performance.ResultsCOP AP time series generally became more random (higher ApEn value) during dual task performance, resulting in a main effect of cognitive task (p = 0.004). In contrast, there was no significant effect of cognitive task for ApEn values of COP ML time series, RMS displacement (AP or ML) or ES.ConclusionDuring dual task performance, ApEn revealed a change in the randomness of COP oscillations that occurred in a variety of sensory conditions, independent of changes in the amplitude of COP oscillations. The finding expands current support for the potential of ApEn to detect subtle changes in postural control. Implications for future studies of attention in neuroscience and physical rehabilitation are discussed.

Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees

Background Microprocessor-controlled knee joints appeared on the market a decade ago. These joints are more sophisticated and more expensive than mechanical ones. The literature is contradictory regarding changes in gait and balance when using these sophisticated devices. Methods This study employed a crossover design to assess the comparative performance of a passive mechanical knee prosthesis compared to a microprocessor-controlled knee joint in 15 subjects with an above-knee amputation. Objective measurements of gait and balance were obtained. Results Subjects demonstrated significantly improved gait characteristics after receiving the microprocessor-controlled prosthetic knee joint ( p < 0.01). Improvements in gait were a transition from a hyperextended knee to a flexed knee during loading response which resulted in a change from an internal knee flexor moment to a knee extensor moment. The participants’ balance also improved ( p < 0.01). All conditions of the Sensory Organization Test (SOT) demonstrated improvements in equilibrium score. The composite score also increased. Conclusions Transfemoral amputees using a microprocessor-controlled knee have significant improvements in gait and balance.

Learning Effects of Repetitive Administrations of the Sensory Organization Test in Healthy Young Adults

Wrisley DM, Stephens MJ, Mosley S, Wojnowski A, Duffy J, Burkard R. Learning effects of repetitive administrations of the Sensory Organization Test in healthy young adults. Objectives To evaluate the learning effect of multiple administrations of the Sensory Organization Test (SOT) on performance and to begin to establish clinical meaningful change scores for the SOT. Design Descriptive case series. Setting University-affiliated clinic. Participants Healthy young adults (6 men, 7 women; mean age, 24±4y). Intervention All subjects performed the standardized SOT using the SMART EquiTest 5 times over a 2-week period, and 1 month later. Main Outcome Measure Composite and individual SOT test condition standardized equilibrium scores. Results Test-retest reliability (intraclass correlation coefficient model 2,3) of the composite (.67) and equilibrium score (range, .35–.79) were fair to good. Repeated-measures analysis of variance revealed a significant ( P<.05) increase in the composite and equilibrium scores for conditions 4, 5, and 6 over the 5 sessions that plateaued after the third session, and were retained at 1 month. The 95% confidence interval for the composite score change from session 1 to session 4, the plateau of the learning effect, was 3.9 to 8.1. Conclusions Although the findings of this study would indicate that multiple baseline measures are desirable for the more challenging conditions, a composite change of greater than 8 points would indicate change due to rehabilitation.

Balance in healthy individuals assessed with Equitest: Maturation and normative data for children and young adults

The purpose of the present prospective study was to obtain normative data for Equitest computerized dynamic posturography (CDP) in children and young adults and to observe the balance maturation process. Equilibrium pattern and SOT of 195 healthy children aged from 6 to 14 years were compared to those of 64 young adults aged 20 years, using Equitest. The mean stability scores for children progressively improve with age and are significantly lower than those of young adults. Furthermore, sensory organization scores were lower in children compared to young adults, whereas visual preference scores were similar for the whole studied groups. According to previous literature, it may be stressed that due to a presumed incomplete development of vestibular system and central nervous system integration, children unlike young adults have lower equilibrium scores, especially when visual information was not available or was incorrect. Our results confirm previous ones obtained in children and young adults with Equitest CDP. This study also provides Equitest data for these age groups, which complete those that have been previously reported.

Effect of Orthoses on Postural Stability in Asymptomatic Subjects With Rearfoot Malalignment During a 6-Week Acclimation Period

Mattacola CG, Dwyer MK, Miller AK, Uhl TL, McCrory JL, Malone TR. Effect of orthoses on postural stability in asymptomatic subjects with rearfoot malalignment during a 6-week acclimation period. Objective To determine the effect of custom-fitted orthoses on postural sway over a 6-week acclimation period. Design Repeated-measures analysis of variance on postural sway measures with factors being group (control, malaligned), time (initial, 2wk, 4wk, 6wk postintervention), and condition (with orthoses, without orthoses). For single-limb stance, side (right, left) was analyzed to determine bilateral differences. Setting Biodynamics laboratory. Participants Twenty-one subjects, 11 asymptomatic with rearfoot malalignment and 10 asymptomatic with normal rearfoot alignment. Interventions Orthoses were prescribed and worn for 6 weeks. Balance testing was performed on 4 different dates with each subject tested in both orthotic conditions. Postural control was measured with three 10-second eyes-closed trials for single-limb stance, one 20-second eyes-closed bilateral stance with the platform moving, and one 20-second eyes-open bilateral stance with the platform and surroundings moving. Main Outcome Measures Sway velocity (in deg/s) for single-limb stance and equilibrium score for bilateral stance. Results Postural sway measures were significantly decreased during single-limb testing with orthoses versus without orthoses, regardless of group. The orthotic intervention significantly improved bilateral stance equilibrium score in the malaligned group at weeks 2, 4, and 6 when compared with measures at the initial week. Equilibrium score of the malaligned group with orthoses at initial week was significantly lower (worse) than the control group with orthoses at initial week; however, these results were not repeated during measurements taken at weeks 2, 4, or 6. Conclusions The application of orthoses decreased sway velocity for single-limb stance, improving postural stability regardless of group when visual feedback was removed. During bilateral stance, postural stability was initially worse for the malaligned group with and without orthoses when compared with the control group; however, improvements were seen by week 2 and continued throughout the remainder of testing. Clinically, the application of orthoses appears to improve postural control in people with rearfoot malalignment, particularly when vision is removed.

Generalizability of the Sensory Organization Test in College-Aged Males: Obtaining a Reliable Performance Measure

This study used generalizability theory to (1) determine the reliability of the six Sensory Organization Test (SOT) conditions, and (2) to determine the most effective testing schedule to obtain reliable posture measurements. Generalizability theory was used to determine the most effecting testing protocol to obtain reliable assessments of postural sway in various sensory environments. Twenty-five recreationally active college-aged males. University research laboratory. None. Postural stability as measured by equilibrium score (a percentage measure indicating amount of sway, with lower scores indicating a greater amount of postural sway). Scores were obtained for each of the six sensory conditions across multiple trials, tests, and days. This study showed that performing the SOT twice on a single testing day was sufficient to achieve moderate to good reliability across the six conditions of the SOT. Extending SOT testing to twice on 2 days yielded good to excellent reliability estimates across all SOT conditions. Taken together, these results indicate that for the purpose of monitoring changes in the postural control system, an individual needs to experience the full complement of SOT testing conditions at least twice. However, if highly reliable baseline measures of SOT performance are necessary, multiple tests performed on multiple days are warranted.

A Comparison of Psychometric Properties of the Smart Balance Master System and the Postural Assessment Scale for Stroke in People Who Have Had Mild Stroke

Chien C-W, Hu M-H, Tang P-F, Sheu C-F, Hsieh C-L. A comparison of psychometric properties of the Smart Balance Master system and the Postural Assessment Scale for Stroke in people who have had mild stroke. Objective To compare the psychometric properties (including the test-retest reliability, responsiveness, and predictive validity) of the Smart Balance Master (SBM) system and the Postural Assessment Scale for Stroke patients (PASS) in patients with mild stroke. Design One repeated-measures design (at a 2-wk interval) was used to examine the test-retest reliability of the SBM and PASS, and another similar design was applied to investigate their responsiveness. Patients who participated in the responsiveness study were followed up approximately 1 year later, and the predictive validity of the SBM system and PASS were examined by assessing the patients’ comprehensive activities of daily living (ADL) function. Setting Three rehabilitation units in Taiwan. Participants Twenty patients with chronic stroke in the reliability study; 40 and 32 patients who had recently had a stroke in the responsiveness and predictive validity studies, respectively. Interventions Not applicable. Main Outcome Measures Three computerized tests of the SBM (the equilibrium score of the Sensory Organization Test, scores in rhythmic weight-shifting tests, and scores in the limits of stability test) and the PASS were used. The combination of the Barthel Index and Frenchay Activities Index was used to represent the comprehensive ADL function. Results For the SBM, all but the weight-shifting tests of the SBM had moderate to high reliability (intraclass correlation coefficient [ICC] range, .78−.91). The responsiveness of the equilibrium score and the limits of stability test were moderate (effect size [ d], .63) and small ( d range, .27−.33), respectively, whereas the responsiveness of the weight-shifting tests was limited ( d range, .04−.29). All but the weight-shifting tests of the SBM in the second evaluation had acceptable predictive validity for comprehensive ADL function ( r 2 range, .15−.17). The PASS showed high reliability (ICC=.84) and small responsiveness ( d=.41), and the PASS in the second evaluation had acceptable predictive validity ( r 2=.24). Conclusions The PASS and the equilibrium score and limits of stability scores of the SBM had acceptable test-retest reliability, responsiveness, and predictive validity in patients with mild stroke, but the psychometric properties of the weight-shifting tests of the SBM should be further examined before consideration of their usage in patients with stroke.

3.303 Posturographic correlates of postural instability in patients with idiopathic Parkinson's disease on and off medication

Background: Researches characterizing postural instability in idiopathic Parkinson's disease (IPD) provides insights into the possibly disturbed mechanisms for postural control. There is however paucity of researches that are interested in providing multisystem evaluation for detection of possible contribution of different systems to balance disturbance in IPD patients. Objective: To study posturographic correlates of postural instability in IPD and on antiparkinsonian medication to determine the exact pathophysiologic mechanisms underlying their balance problems. Methods: Fifteen IPD patients (on and state) were compared to ten healthy control subjects. Patients underwent clinical examination including Unified Parkinson Disease Rating Scale (UPDRS) and Hoehn Yahr Scale together with posturographic evaluation including sensory organization test, motor control test, and neurotesting (akinesia test, retropulsion test, and bradykinesia test). The posturographic parameters were compared to those of control group. Results: Compared to controls, IPD patients off state had significantly low composite equilibrium score and significantly low visual ratio and visual preference ratio of the sensory organization test. Elevated automatic postural thresholds were detected only to medium sized forward translation during motor control test. Significantly prolonged reaction and movement times together with defective pacing characterized patients’ movement during neurotesting. Partial improvement was found in all clinical subscales and in some of posturographic parameters in response to antiparkinsonian medication. Conclusion: Both sensory and motor components of balance are important contributors to postural instability in IPD. Visual dysfunction dominated sensory abnormality. Motor abnormalities contributing to postural disturbance may be the result of increased rigidity, defective timing components of balance, and defective force generation. (Egypt J Neurol Psychiat Neurosurg. 2010; 47(1): 185-196)

THE EFFECT OF A MODIFIED JAZZ DANCE CLASS ON BALANCE IN OLDER WOMEN.

Purpose/Hypothesis: The purpose of this study was to assess the impact of age-appropriate jazz dance class instruction on balance for women utilizing dynamic posturography. Subjects: Fourteen healthy elderly women aged from 52 to 88 participated in the study. All were a sample of convenience of volunteers recruited from a Senior Dance Techniques course offered by the Department of Dance at the University of Nevada, Las Vegas. Materials/Methods: The subjects completed a 15-week jazz dance program in which the subjects attended one time per week for 50 minutes in duration. Baseline balance data were collected through the use of the Sensory Organization Test (SOT) as administered using the NeuroCom Smart® Balance Master System (Balance Master) during weeks 1 and 2 of the class. The second measurement was recorded between weeks 7 and 8 and the final measurement was taken after week 15 of the class. Means and standard deviations were calculated for the outcome variables. A repeated measures ANOVA was used to compare the means of each subjects' SOT composite equilibrium score over the 3 measurement time frames. The composite equilibrium score reflects the overall performance on the SOT and is the sum of all 6 conditions. Alpha levels were set at 0.05. Results: There was a statistically significant difference among the mean SOT composite equilibrium scores (F(2,22) = 23.185) for pre, mid, and post time intervals as follows: Pre= 67.333, SD= 10.430; Mid= 75.250, SD= 6.969; Post= 79.000, SD= 4.973, (p<0.0005). Pairwise (Bonferroni) post-hoc analyses revealed the following statistically significant findings for SOT composite equilibrium scores for the pre, mid, and post measurements: Pre-Mid (p= 0.008); Pre-Post (p< 0.0005); Mid-Post (p= 0.033). Conclusions: The results of this study suggest that administration of a jazz dance program as an alternative to a traditional exercise program is beneficial in improving balance as measured by the Balance Master. Future research should consider the comparison of different exercise or dance groups and larger sample sizes. Clinical Relevance: Many elderly may not have the opportunity or desire to perform an exercisebased program. Since many elderly experience a loss of stability, they seek to compensate by restricting their activity levels, thereby avoiding falling. However, given the social proclivity of elderly individuals, many do find dance as an attractive alternative to an exercise regimen. The findings from this study reveal that dance-based training is beneficial in improving balance, which may help to decrease fall risk.