Plegic limb classification using cluster analysis

Postural sway in children from pedigrees exhibiting a high density of alcoholism

Postural sway during quiet standing reflects the interplay between destabilizing forces acting on the body and actions by the postural control system to prevent a loss of balance. Hence, balance impairments caused by altered sensory, motor, or central nervous function related to such factors as

Influence of dual tasks on sitting postural sway in children and adolescents with myelomeningocele

The present study examined, in children aged 4-11 and in adults, the postural control modifications when attention was oriented voluntary on postural sway. Since (1) there are less attentional resources in children than in adults, (2) the selective attention processing improves with age, i.e., children use a different strategy to focus their attention than adults, and (3) adults' postural stability decreases when attention is focused on postural sway, we hypothesized that postural stability was less affected in children than in adults when attention was focused on postural sway. Fourty four children aged 4- to 11-year-old and 11 adults participated in the experiments. The postural control task was executed in a Romberg position. Two experimental conditions were presented to the subjects, (1) to look at a video on a TV screen without instruction about the posture, and (2) to fixate a cross placed at the center of the TV screen with the instruction to remain as stable as possible. Postural performance was measured by means of a force platform. Results from this study (1) confirmed a non-monotonic improvement of postural stability during the ontogenetic period without reaching the adults' level at the age of 11, (2) suggested that children, aged 4-11, are able to focus their attention on the control of posture, and (3) showed that the automatic control of posture increases postural stability since the age of 4.

Postural sway as a marker of progression in Parkinson's disease: A pilot longitudinal study

Current methods of measuring gross motor abilities in children involve either high-cost specialist apparatus that is unsuitable for use in schools, or low-cost but nonoptimal observational measures. We describe the development of a low-cost system that is capable of providing high-quality objective data for the measurement of head movements and postural sway. This system is based on off-the-shelf components available for the Nintendo Wii: (1) The infrared cameras in a pair of WiiMotes are used to track head movements by resolving the position of infrared-emitting diodes in three dimensions, and (2) center-of-pressure data are captured using the WiiFit Balance board. This allows the assessment of children in school settings, and thus provides a mechanism for identifying children with neurological problems affecting posture. In order to test the utility of the system, we installed the apparatus in two schools to determine whether we could collect meaningful data on hundreds of children in a short time period. The system was successfully deployed in each school over a week, and data were collected on all of the children within the school buildings at the time of testing (N = 269). The data showed reliable effects of age and viewing condition, as predicted from previous small-scale studies that had used specialist apparatus to measure childhood posture. Thus, our system has the potential to allow screening of children for gross postural deficits in a manner that has never previously been possible. It follows that our system opens up the possibility of conducting large-scale behavioral studies concerning the development of posture.

Postural sway in children and young adults, survivors of CNS tumours

BackgroundEarly and accurate diagnosis of multiple sclerosis (MS) is crucial for its effective treatment. In MS diagnostic, neuronal networks that control posture and movement are of particular importance, which performance can be assessed using static posturography. Unfortunately, most of the commercially available posturographic platforms are not equipped with the appropriate procedures. MethodsTo solve this problem, the postural sway trajectories have been recorded in 55 MS patients while standing quiet with eyes open (EO), and then with eyes closed (EC). The trajectories were analyzed using our novel methods of postural sway parametrization, including sway stability vector (SV), anteroposterior and mediolateral sway indices (DIAP and DIML). ResultsThe results exhibited unique postural sway patterns that may be attributed to MS. Our novel parametrization methods of postural sway showed pathology specific increase of the postural sway velocity in EC tests. Additionally, we documented the abnormal alterations of the anteroposterior (AP) and the mediolateral (ML) sway indices that were also uniquely dependent on visual input. In EC tests, patients exhibited a characteristic pattern of sway increase in both AP and ML directions that correlated with the advance of the disease as measured by the EDSS Kurtzke scale and Functional System Scores. ConclusionsThe applied in the present study our novel posturographic metrics give the assessment a diagnostic value. It allows us to recommend the static posturography test as a simple and safe supplementary clinical tool in the diagnosis of MS. In the assessment of MS pathology or the effects of its treatment, the impact of vision on the sway stability vector seems the most important factor.

It is known that impaired balance is associated with falls in older adults; however, there is no accepted gold standard on how balance should be measured. Few studies have examined measures of postural sway and clinical balance concurrently in large samples of community-dwelling older adults. We examined the associations among 4 types of measures of laboratory- and clinic-based balance in a large population-based cohort of older adults. We evaluated balance measures in the Maintenance of Balance, Independent Living, Intellect and Zest in the Elderly Boston Study (276 men and 489 women ages 64-97 years). The measures included laboratory-based anteroposterior (AP) path length and mean sway speed, mediolateral (ML) mean sway and root mean square, and area of ellipse postural sway; the Short Physical Performance Battery (SPPB); the Berg Balance Scale; and the one-leg stand test. Spearman's rank correlation coefficients were assessed among the balance measures. The area of ellipse sway was highly correlated with the ML sway measures (r = >0.91, P < 0.0001) and sway speed was highly correlated with AP sway (r = 0.97, P < 0.0001). The Berg Balance Scale was highly correlated with the SPPB (r = 0.74, P < 0.001) and the one-leg stand test (r = 0.82, P < 0.001). Correlations between the laboratory- and clinic-based balance measures were low but statistically significant (-0.29 ≤ r ≤ -0.16, P < 0.0001). Clinic-based balance measures, and laboratory-based measures comparing area of ellipse with ML sways or sway speed with AP sway, are highly correlated. There is less correlation between the clinic- and laboratory-based measures. Since both laboratory- and clinic-based measures inform balance in older adults, but are not highly correlated with each other, future work should investigate the differences.

Consistent motion simulation in Virtual Reality (VR) applications is challenging due to constraints on tracking technologies and locomotion or interaction paradigms that scale motion. In this study, we measured (a) the point of subjective stationarity (PSS) during active self-motion, (b) postural sway in the dark, and (c) visually-induced postural sway during quiet stance, both before and after adapting to different gains between physical self-motion and the motion portrayed in the virtual environment. Participants adapted to each of three adaptation gain levels in separate blocks: normal, reduced, and increased, in which observers' physical motion was scaled and displayed as the virtual motion. We measured PSS during active self-motion and postural sway during quiet stance in both left-right and front-back directions in separate sessions. We found that the PSS measured during self-motion did not vary with adaptation gain. However, postural sway elicited by visual perturbation was modulated after adapting to non-unity gains. We also measured baseline postural sway prior to adaptation and found that exposure to virtual motion under unity (normal) gain increased the postural variability along the left-right direction, when tested without visual feedback (in dark). Collectively these results suggest that while observers adapt to gain, active self-motion provides sufficient somatosensory feedback to counteract the shift in perceived motion. As a result, PSS remains consistent across all gain manipulations in our experiment setup. In contrast, postural responses during quiet stance did not recalibrate immediately after motion gain perturbation was removed suggesting that they operate independently of perceptual mechanisms.

The aim of the study was to investigate the effect of maximal strength training on postural sway after total hip arthroplasty, performed before and after a battery of physical performance tests that resemble daily living activities. This study is an exploratory study based on data from a 3-mo randomized controlled trial involving 54 total hip arthroplasty patients performing maximal strength training or conventional rehabilitation. At 3, 6, and 12 mos postoperatively, postural sway was evaluated in two gait tests; ie, one test before and one test after conducting a battery of physical performance tests. At 3 mos postoperatively, postural sway in the test after was significantly higher for the conventional rehabilitation group than the maximal strength training group (P = 0.045); however, there was no between-group difference at the test before (P = 0.670). Postural sway was also significantly higher in the test after compared with the test before in the conventional rehabilitation group (P < 0.001). No difference was found between the test before and test after in the maximal strength training group (P = 0.713). At 6 and 12 mos postoperatively, there were no statistically significant within- or between-group differences in postural sway. Increased muscular strength limits postural sway 3 mos postoperatively in total hip arthroplasty patients after a demanding battery of physical performance tests simulating daily living activities.

Background: Diabetes is a silent disorder leading to disabling and fatal complications. The long-term complications of diabetes affect almost every system in the body. Balance impairment and postural instability is also observed in people having chronic diabetes which is a result of diabetic peripheral neuropathy, diabetic retinopathy, and vestibular dysfunctions. Objective: The objective of this study is to find out the effect of chronic diabetes on postural sway by Romberg’s test and thereby finding effects of diabetes on balance and stability. Method: 60 participants both male and female between 40 to 60 years of age were included. The participants were divided into diabetic and non-diabetic group (n=30). All the participants performed Romberg’s test. Their postural sway was observed and subsequently Romberg’s sign was noted. The procedure is repeated again two more times to find out average Romberg’s sign. Results: The data shows a significant difference in postural sway between diabetic and non-diabetic subjects. The chi-square value computed for this comparison was 5.406, yielding a p-value of 0.020. The p-value was below the conventional significance threshold of 0.05, indicating a statistically significant association between diabetes status and the presence of postural sway. Diabetic individuals were significantly more likely to exhibit signs of impaired balance compared to non-diabetic individuals, as evidenced by the highly significant chi-square test result. This finding highlights the impact of diabetes on balance and stability. Conclusion: The study demonstrated that postural sway and instability was more common in diabetic subjects as compare to non-diabetic subjects between 40 to 60 years of age. Additionally, this study suggested that patients having diabetes should take measures to prevent postural instability, balance impairments and other complications of diabetes.

Context-dependent coupling of posture, gait, and functional mobility under cognitive and sensory demands in Parkinson's disease.

Increasing mediolateral standing sway is associated with increasing corticospinal excitability, and decreasing M1 inhibition and facilitation

Age-specific reference intervals (RIs) have been developed for biochemistry analytes in children. However, the ability to interpret results from multiple laboratories for 1 individual is limited. This study reports a head-to-head comparison of reference values and age-specific RIs for 30 biochemistry analytes for children across 5 analyzer types. Blood was collected from healthy newborns and children 30 days to <18 years of age. Serum aliquots from the same individual were analyzed on 5 analyzer types. Differences in the mean reference values of the analytes by the analyzer types were investigated using mixed-effect regression analysis and by comparing maximum variation between analyzers with analyte-specific allowable total error reported in the Westgard QC database. Quantile regression was used to estimate age-specific RIs using power variables in age selected by fractional polynomial regression for the mean, with modification by sex when appropriate. The variations of age-specific mean reference values between analyzer types were within allowable total error (Westgard QC) for most analytes, and common age-specific reference limits were reported as functions of age and/or sex. Analyzer-specific reference limits for all analytes on 5 analyzer types are also reported as functions of age and/or sex. This study provides quantitative and qualitative measures of the extent to which results for individual children can or cannot be compared across analyzer types, and the feasibility of RI harmonization. The reported equations enable incorporation of age-specific RIs into laboratory information systems for improving evidence-based clinical decisions in children.