Balance Test Results Research Articles

Vestibular myogenic potentials of athletes for the Deaf Olympic Games with congenital profound hearing loss

Conclusions: Our study revealed that VEMPs in responses to clicks and 500 Hz STB were abnormal in 25% of athletes with congenital profound sensorineural hearing loss for the Deaf Olympic Games. These results confirm that a part of deaf athletes with congenital vestibular failure is well compensated for higher level sport activities. Objectives: The aim of this study was to investigate the appearance rate of VEMP, vestibular failure and its compensation in Japanese deaf athletes by the VEMP test, caloric test and balance test. Methods: Sixteen subjects among the Deaf Olympic Games athletes of Japan volunteered to participate in this study. All the subjects have congenital profound sensorineural hearing loss. Results: In the VEMP test, 24 ears (75%) showed normal click-evoked responses, 5 ears (16%) showed decreased click-evoked responses, 3 ears (9%) showed no click-evoked responses, 28 ears (87.5%) showed normal 500 Hz short tone burst (STB)-evoked responses and 4 ears (12.5%) showed decreased responses. In the ice-water caloric test, 11 subjects (69%) showed normal responses bilaterally, 3 subjects showed bilateral responses with asymmetrical responses and 2 subjects (12%) showed no response bilaterally. All the subjects showed normal balance test results.

Effect of the Feed Additive Clinoptilolite (ZeoFeed) on Nutrient Metabolism and Production Performance of Laying Hens

The aim of this study was to assess the effects of two levels of clinoptilolite administered in feed (2% and 4%) on some selected performance indicators, metabolic utilization of basic nutrients and the health status of laying hens. The selected 24 Bovans Goldline hybrid laying hens were divided into three equal groups, two experimental groups (E1 and E2) and one control group (C). The laying hens were housed individually in cages with an automatic supply of drinking water, manual feeding, in a setting with controlled light and temperature regimens. Hens from individual groups were all fed a complete feed mix of the same composition and the only difference was in clinoptilolite supplementation: feed mixes for E1 and E2 groups contained 2% and 4% of clinoptilolite (commercial additive ZeoFeed) respectively, replacing the same amounts of wheat. The hens received feed mixes and drinking water ad libitum. During this 28-day experiment, feed consumption and the number and weight of eggs laid were monitored individually for each hen. At the end of the experiment, the balance test using the indicator method (Cr2O3) was performed in all eight hens in each of the groups. The results of balance tests were then used to calculate the metabolic utilization of selected nutrients (nitrogen, fat, ash, nitrogen-free extracts, starch, gross energy, Ca, P). After the balance tests, blood samples for haematological and biochemical examinations were collected via puncture of the vena basilica. The addition of 2% clinoptilolite to feed mix resulted in a highly significant (P ⪬ 0.01) increase in mean egg weight to 64.69 g, but the addition of 4% clinoptilolite in group E2 resulted in a highly significant (P ⪬ 0.01) decrease in mean egg weight to 62.20 g compared to the control (63.73 g). Moreover, daily feed mix consumption in group E1 decreased to 114 g per one laying hen/day compared to the controls (118 g per one laying hen/day). In group E2 (4% clinoptilolite), daily consumption of feed mix increased compared with the controls to 124 g. The 2% clinoptilolite supplementation of E1 group feed slightly increased metabolic utilization of fat, nitrogen-free extracts, starch and gross energy compared to group C. Results of haematological test of the hens’ blood showed significant changes in haemoglobin, whose values in groups C and E1 were significantly higher (P ⪬ 0.05) than in group E2. Differences in the values of the biochemical indicators monitored (total protein, glucose, cholesterol, triacylglycerols, calcium, phosphorus, magnesium and the AST enzyme) between group C and experimental groups E1 and E2 were not significant and remained within the range of reference values.

Wettability of Lead-Free Solders on Gold-Plated Copper Substrates

Wettability of lead-free solders (Sn-3Ag-0.5Cu, Sn-8Zn-3Bi, and Sn-9Zn) on Au-plated copper substrate was investigated with three different thicknesses of Au layer (0.1 μm, 0.3 μm, and 0.5 μm). The contact angles of solder alloys did not show a dependence on Au thickness. The contact angles of Sn-3Ag-0.5Cu and Sn-9Zn decreased, whereas the contact angle of Sn-8Zn-3Bi remained constant with an increase in temperature. Wetting balance test results indicated that thickness of Au plating affects wetting force, with thinner plating showing stronger wetting force and therefore, lower wetting time. Effects of different fluxes on wettability were also studied.

A procedure for constructing the normative characteristics of chimney-type evaporative cooling towers from the results of field measurements

A procedure for constructing the normative characteristics of chimney-type evaporative cooling towers equipped with different designs of heat-and-mass transfer (spraying) devices is developed using the results of balance tests carried out for many years on 34 cooling towers of different designs with areas ranging from 500 to 10000 m2.

The impact of tail tip amputation and ink tattoo on C57BL/6JBomTac mice

Genetic material for polymerase chain reaction (PCR) and Southern blot analysis on transgenic mice is normally obtained by tail biopsy. Additionally, it may be necessary to tattoo the mice, as it is essential to have a good and permanent identification. The aim of this study was to evaluate the effects of amputating the tip of the tail to obtain a biopsy for genetic analysis and of ink tattooing on welfare in C57BL/6J mice, a strain often used as genetic background for transgenes. The behaviour of the animals, fluctuating asymmetry (FA, a measure of developmental instability) and the level of restitution in the remaining part of the tail were evaluated and used for an assessment of the impact of these procedures on the welfare of the animals. One group of mice was marked by tail tattooing at various ages. Another group of mice were tail amputated at 12 or 20 days of age. Body weight and FA were followed, and at the end of the experiment, the level of fear/anxiety was assessed using a light-dark box. In the group of tail-amputated animals observation of climbing behaviour and a beam walking test for balance was performed. Seven weeks after tail amputation, the animals were euthanized. The remaining part of the tail was evaluated histopathologically. Body weight, behaviour in the light-dark box and balance test results were not influenced by tail amputation or tattooing. FA was only transiently increased by tattooing. Climbing behaviour was reduced just after tail amputation at 20 days of age. No signs of neuromas were found in the amputated tails, but seven weeks after amputation a significant number of mice did not have fully regenerated glandular tissue and hair follicles in the tail. It is concluded that both tail amputation and tail tattooing seem to have minor short-term negative effects on welfare and that the tissues on the tail probably do not regenerate fully after amputation.

The Role of Foot Position in Postural Stability and Balance

PURPOSE: The use of assessing the quality and accuracy of task specific movement patterns to identify deviation in posture, balance and dynamic movement or to note improvement with an intervention is becoming more prominent in the literature. It is unclear if the foot position at the time of assessment would influence the quality of the movement pattern. The purpose of this study is to determine if foot position would effect dynamic postural balance as measured by the translation of the center of pressure using the MatScan® System (Tekscan). METHODS: A repeated measures design was used testing subjects under two conditions, (1) self-selected foot position (SSFP) and (2) standardized biomechanical foot position (SBFP) (15 deg of ER and 6 inches between the bisection of the calcaneous). Testing occurred in a controlled laboratory setting in a single session. Twenty subjects (10 males and 10 females), mean age 21 ± 1.3 yrs, mean height 168.6 ± 8.1 cm and mean weight of 73.05 ± 14.92 kg participated in this study. The force data was collected at 40 Hz. using the MatScan® System (Tekscan). Subjects were instructed to squat to 60 degrees of knee flexion in two seconds guided by audio cues from the researcher of “ready, set, down, up” in conjunction with a metronome while standing on the MatScan®. Real time data acquisition tracking the translation of the center of pressure during the squatting movement was then used to calculate the variables of Area, Distance and Variability. Area, thought to reflect postural sway, represents the translation of the COF using X and Y excursions and the formula for an ellipse. Distance represents the total excursion of the COF (calculated using the Pythagorean Theorem) across the selected duration of time and represents overall postural adjustments. Variability is the standard deviation of the moment to moment distances and is thought to reflect fine postural adjustments. RESULTS: There were statistical significant differences between SSFP and the SBFP for both Area (p = 0.005; t19= −3.208) and Distance (p = 0.004; t19 = −3.289). For Area (representing postural sway), the mean value for SSFP was 12.04 ±5.83 cm2 and 8.71 ±2.67 cm2 for the BSFP, a 27.66% decrease. For Distance (representing overall postural adjustments), the mean value for SSFP was 19.43±3.82 cm and 17.35±2.48 cm for the BSFP, a 10.71% decrease. CONCLUSIONS: The results lead to conclude that foot position influences postural balance during a dynamic movement pattern. A predetermined SBFP may limit the external generalization and the clinical application of the balance test results.

Sn concentration on the reactive wetting of high-Pb solder on Cu substrate

In order to explore the mechanism of reactive wetting occurred between solder and Cu substrate, the wetting behavior of high-Pb, say, Pb- xSn solder ( x = 0, 0.7, 1.4, 2.1, 2.8, and 3.5 wt.%, respectively) was investigated using the wetting balance technique. It was found that small amount of addition Sn in Pb could improve the wettability of Pb- xSn solder on Cu severely. Since the current reactive wetting theory suggested that the first intermetallic compound formed during the wetting reaction could influence the wetting properties, the driving forces of the intermetallic compounds formation under metastable equilibrium were calculated using Thermo Calc software. And the first intermetallic compound was confirmed to be Cu 3Sn by both theoretical computation and EDX analysis. The reactive wetting theories was employed, and combined with the analysis of wetting balance test results, to discuss the wetting phenomena herein.

Functional, postural and perceived balance for predicting the work ability of firefighters

The importance of balance abilities for firefighting and rescue work has already been recognized, but there are no valid balance tests available in the test batteries for the physical work capacity of firefighters. Moreover, few studies have examined the associations between balance and work ability in general. Valid work-related balance tests are needed for the purpose of screening in occupational health care and in rehabilitation for assessing the effects of balance training. This study aimed to investigate the predictive value of functional, postural and perceived balance in respect to work ability among firefighters at baseline and after a 3-year follow-up. The subjects were 135 male firefighters aged 33-56 years. The outcome variables were the work ability index and perceived physical work ability (PWA), determined by questionnaire in 1996 and 1999. The predictors assessed in 1996 were postural balance (tested with a force platform), functional balance (measured during walking on a wooden plank), and perceived balance abilities, enquired about through a questionnaire. Most of the balance test results and the perceived balance ability were associated with the perceived PWA at baseline. The final logistic regression models showed that the best predictors of decreased work ability among firefighters after 3 years were poor-to-moderate perceived balance [odds ratios (ORs) 2.4, 95% confidence interval (CI) 0.9-6.6]; more than one error in the functional balance test (OR 3.6, 95% CI 1.0-12.7); and a high mean amplitude of postural sway with the eyes closed (OR 2.7, 95% CI 0.9-6.1). The results support the work-related and predictive validity, in terms of perceived work ability, perceived balance, errors in the functional balance test and amplitude of postural sway with the eyes closed, of measuring balance among firefighters.

Looking at the relationship between hemoglobin concentration and prevalent mobility difficulty in older women. Should the criteria currently used to define anemia in older people be reevaluated?

The World Health Organization (WHO) and other currently used criteria for defining anemia in older women are mainly based on statistical distribution considerations. To explore their clinical appropriateness, we evaluated the relationship between hemoglobin (Hb) concentration, prevalent mobility difficulty, and the Summary Performance Score (SPS). Cross-sectional study. Two population-based studies, the Women's Health and Aging Studies I and II, Baltimore, Maryland. Six hundred thirty-three community-dwelling women aged 70 to 80 with Hb levels obtained within 90 days from baseline assessment. Mobility difficulty (self-reported difficulty walking one-quarter of a mile or climbing 10 steps (primary outcome)). SPS, a performance-based summary measure of lower extremity function that combines the results of walking, chair stands, and balance tests (secondary outcome). Mobility difficulty prevalence was not constant within the WHO "normal" Hb range (12.0-16.0 g/dL). For example, a Hb of 13.5 g/dL was associated with a significantly lower mobility difficulty prevalence than a Hb of 12.0 g/dL (OR=0.68, 95% CI=0.47-0.93), even after adjustment for chronic diseases and other relevant health indicators. A consistent trend of improvement in performance-based scores with increasing Hb categories less than 12.0 g/dL, 12.0 to 13.0g/dL, and 13.0-14.0 g/dL was observed. Our findings raise two hypotheses: (1) Hb currently perceived as "mildly-low" and even "low-normal" might have an independent, adverse effect on mobility function, and (2) Hb of 12.0 g/dL might be a suboptimal criterion for defining anemia in older women. Formal testing of these hypotheses might prove relevant for anemia- and mobility disability-related clinical decision-making.

A prospective study of laboratory and clinical measures of postural stability to predict community-dwelling fallers.

The identification of specific risk factors for falls in community-dwelling elderly persons is required to detect early changes and permit a preventative approach to management. This study determines the ability of various laboratory measures and clinical tests of postural stability to prospectively predict fallers in community-dwelling elderly women. One hundred elderly women (65-86 years, mean age 73 +/- 5 years) performed a reaction-time step task, a limits of stability, and a quiet stance balance task. Postural muscle timing and movement speed were recorded during the step task. Center of pressure (COP) motion was recorded in quiet stance and at the limits of stability. Four common clinical balance tests were performed, and balance confidence, medical and activity history questionnaires were completed. Subjects were followed up regularly for a 6-month period following testing to determine the frequency and characteristics of any falls that occurred. Predictive capabilities of the balance measures to determine fallers were determined through logistic regression models. The clinical balance tests investigated were not able to predict fallers in this community-dwelling elderly population. A combination of variables from the laboratory tasks provided the best overall prediction rate (77%) of fallers (sensitivity 51%) and nonfallers (specificity 91%) from laboratory measures. Of these, step movement time and gluteus medius onset times were the factors best able to predict fallers. Alone, measures of COP motion in quiet stance and at the limits of stability had a poor ability to predict fallers, although they could correctly identify most nonfallers. Prediction was not significantly improved when clinical balance test results were added to the most predictive laboratory measures. Not all older adults with a reduction in balance ability reported a fall over a 6-month period. Of those who did, a combination of measures reflective of different aspects of mediolateral postural stability during a rapid step task, quiet stance, and movement to the limits of stability were best able to predict faller status, with nonfallers better predicted than fallers. These results emphasize the importance of the multifactorial nature of falls in the community-dwelling elderly population in that the clinical and laboratory measures did not predict a high proportion of fallers.

Past history of otitis media and balance in four-year-old children.

To obtain normative data for a population of children 4 years of age with respect to standard vestibular and balance test protocols and to determine, in the absence of concurrent middle ear effusion (MEE), the possible changes caused by a history of recurrent or persistent MEE. Comparative studies of the results of vestibular and balance tests in a cohort of young children with and without a history of MEE. Seventy-one children, 4 years of age, with a well-documented history since early infancy regarding the presence or absence of MEE were evaluated using pneumatic otoscopy, tympanometry, audiometry, and vestibular and balance (rotational and moving platform posturography) tests. For the results of the vestibular and balance tests, comparisons were made between the group of 31 children (43.7%) without and the group of 40 children (56.3%) with a history of recurrent or persistent MEE, when a positive disease history was defined as at least a 10% cumulative percentage of time with MEE between early infancy and time of testing. When compared with children with a negative history of significant MEE, children with a positive history had a lower average gain to a rotational stimulus of 0.1 Hz, 150 degrees/s (0.57 vs. 0.44; P = .007). There were no significant differences between groups with respect to other measures. These results suggest that a history of recurrent or persistent MEE affects the vestibular and/or balance function of 4-year-old children when tested in the absence of a concurrent episode of MEE. The possible sequelae of the disease should be weighed in future considerations of early intervention for MEE.

Running hamster: a new type of mutant characterized as speedy, rotative running without motor and balance deficits.

Running hamster OYC (RHO) is a mutant spontaneously arisen in a closed colony of Armenian Hamsters and has a characteristic of speedy, rotative running behavior. There are several reports which describe such mutants as abnormal walking behavior in rodents due to ataxia or balance deficits. In this report, we describe results of several motor and balance tests in order to clarify whether or not RHO mutants have such disorders. RHO mutants showed no sign of either motor or auditory deficits, and scarcely had balance deficits tested. The animals only had slight head tilting at the starting of running. These results suggest that RHO is a really new type of mutant which has not previously been reported.

Simulation and Interpretation of Wetting Balance Tests Using the Surface Evolver

The wettability of PCB pads and component terminations, and the variation of wetta-bility with time, are important factors in the successful formation of a solder joint. However, reliable techniques for determining these properties, under conditions representative of the soldering process, do not as yet exist. The development of wetting balance tests has provided a technique for the qualitative comparison of surface wettability, but the test has poor repeatability and it is difficult to relate the test results to the actual surface properties. The small size of the terminations in surface mount technology (S.M.T.) prevents successful use of the conventional solder bath based wetting balance test. The globule wetting balance goes some way towards removing this limitation and is now often used as a means of comparing the solderability of S.M.T. devices, but is even worse in terms of repeatability and interpretation. This paper presents results from an evaluation of conventional and globule wetting balance tests using both computational modelling and experimental techniques. The results from the experimental tests show that reasonable consistency in the measured force can be obtained, but that the insensitivity of this force to the wetting angle of the component, particularly in the globule block test, precludes their ability to accurately establish the wetting angle. It is therefore concluded that this test is unsuitable for providing direct quantitative measurements of the wetting angle of the surface of interest. The computational models, through allowing an analysis of the sensitivity of the test to the uncontrolled test variables also provide an explanation for the significant scatter obtained in wetting balance test results. It is also seen, from comparison with test results, that models which incorporate commonly quoted text book values for the solder surface tension do not adequately predict the forces empirically observed. A technique is therefore also described whereby the solder surface tension under the actual test conditions may be deduced using the results from a scanning mode wetting balance test, thereby greatly improving the capability of the models to predict the surface tension forces, although significant errors in the predicted meniscus shape remain.

Balance and Motor Skills in Young Children With Sensorineural Hearing Impairment

The purpose of this study was to compare the static and dynamic balance, motor abilities, and postrotatory nystagmus (PRNT) test results of four- to five-year-old children with sensorineural hearing impairment (SNHI) to those of typically developing peers. Seven children with SNHI and six typically developing peers comprised the experimental and control groups, respectively. Static balance was measured as duration of single-leg stance with eyes open and eyes closed. Kinematic analysis of responses during tilt board perturbation with eyes open and eyes closed comprised testing of dynamic balance. Motor abilities were defined by performance on the Learning Accomplishment Profile Gross Motor Subscale. The data indicate that a majority of children with SNHI present with aberrant PRNT results, delayed maturation of equilibrium reactions, and age-appropriate performance in a general developmental screening test. Implications for clinicians working with preschool-aged children with SNHI are discussed, as are directions for future research.

Induced drag of a crescent wing planform

Comparative study, both computational and experimental, has been carried out on the possible drag reduction at low speeds of two wings of same aspect ratio 6, but different wing planforms; one is crescent and the other is elliptic. Computational results, using two inviscid panel programs, indicate that the crescent wing planform is capable of reducing the drag, interpreted from the integrated surface pressure distributions. The benefit has been attributed to a high suction pressure loading in the tip region in the case of the crescent wing. However, such a potential in drag reduction cannot be verified experimentally at the Reynolds number based on the mean chord 0.25 x 10 6. There has been no expected gain in the effective aspect ratio associated with the crescent wing, based on the results of balance tests. Detailed wake surveys at a downstream distance behind these wings reveal substantial differences in the wake structures at an approximate lift coefficient of 0.35, but the vorticity in the wake vortex cores shows similar magnitudes. One explanation for the misleading computational findings is that there exists a residue drag at no-load condition, possibly arising from the errors in the discretization of the highly curved tip shape. This residue drag tends to contaminate the calculation at lifting conditions. a a(} AR b c

The Desynchrony between Complaints and Signs of Vestibular Disorders

As part of an early intervention study on the acceptability of auditory rehabilitative intervention, we examined patient complaints and clinical findings of balance disorders. Hallam et al. have discussed desynchrony between such findings in hospital patient populations, and the aim of the present study was to investigate these relationships in a general population. The study was conducted in two industrial villages in Wales in which questionnaires were circulated to all individuals in the 50-65 age group. A marked desynchrony between semeions and clinical findings was found. This has been related to the desynchrony between auditory impairment, disability and handicap in this population. Subjects reporting giddiness or vertigo were more disabled but not more impaired in respect of auditory measures than those not reporting such balance problems. Those with abnormal balance test results showed no auditory differences from those with normal results.

Chapter 26 A system identification approach to balance testing

By modelling the posture control system as a linear transfer function cascaded with a saturation-like nonlinearity, the problem of quantifying relative stability was reduced to a linear system identification problem. The relative stability of different individuals was quantified in terms of the nominal ‘saturation amplitude’ (SA), the transient perturbation amplitude at which the resulting COP displacement would saturate (or equal the length of) the BOS. To ensure subject safety and to minimize anticipatory adaptations, the transient response was determined indirectly. A small-amplitude pseudorandom perturbation was applied and the results used to identify the linear component of the cascade model. The linear transfer function was then used to predict the large-amplitude transient response, thereby allowing the saturation amplitude to be estimated. Three system identification methods were used: cross spectral, least squares and maximum likelihood. In order to approximate the kinematics and sensory input of typical falling situations, the test perturbation was selected to be an anterior-posterior acceleration of the platform on which the subject stood, with a visual field that moved with the platform. The perturbation waveform, power spectrum, bandwidth, duration and amplitude were selected to meet requirements for persistent excitation, accurate identification, stationarity and subject safety and tolerance. Pilot experiments were performed to aid in the selection of the perturbation parameters. Testing of 64 young and elderly normal adults has shown the balance test to be a sensitive measure of the deterioration in postural control known to occur in normal ageing. Depending on the system identification method used, the balance test has been able to identify up to three of five patients with peripheral vestibular lesions and five of five elderly subjects with a history of falling, at a false positive rate of 25%. Comparison of the model predictions with direct measurements of transient response has indicated that the model may overestimate the response to large transient perturbations; however, the transient test results may have been confounded by adaptive effects. The balance test results have shown no significant correlation with measures of spontaneous postural sway, except in normal young adults.

Experimental studies of fluidized twin-bed boilers for low-grade solid fuels

The construction principle of industrial boiler with two fluidized beds operating in parallel is briefly discussed. According to the results of heat balance tests, it is evident that the thermal efficiency of the boiler, when burning low-grade solid fuels, may be increased from 53.9 to 70.7% as compared with the ordinary single fluidized bed boiler. Dynamic properties of the combustion process in fluidized bed boilers, burning low grade solid fuels with broad size distribution and firing fly ash with narrow size distribution, were determined experimentally. Problems in fluidized bed boiler design and operation examined, and reasons for the increase in thermal efficiency are presented.

The effect of increment size on short increment sensitivity index scores.

The Short Increment Sensitivity Index (SISI test) was given with three increment magnitudes, 1.00 dB, 0.75 dB, and 0.50 dB, to a group of 24 normal hearing subjects and to a group of nine subjects with cochlear lesion hearing loss. The presence of cochlear pathology in the latter group was supported by the results of loudness balance tests of recruitment. The SISI test distinguished the cochlear pathology ear from the normal ear more consistently with the 1.00 dB increment than with either of the two smaller increment magnitudes investigated. The major conclusion of the study is that the SISI test should be continued with the 1.00 dB increment originally proposed.