Measures Of Body Sway Research Articles

Response to alcohol in daughters of alcoholics: a pilot study and a comparison with sons of alcoholics.

Drinking, but not alcohol-dependent, 18-29-year-old daughters of alcoholics (n = 38) from the Collaborative Study on the Genetics of Alcoholism were compared to 75 family-history-positive (FHP) men from the same families, and 68 family-history-negative (FHN) male controls. Subjects received 0.75 ml/kg of ethanol (for women), 0.9 ml/kg of ethanol (for men), and placebo, each of which was consumed over 8 min on different occasions. The breath-alcohol concentrations (BrAC) and reactions to alcohol [using the Subjective High Assessment Scale (SHAS) and body sway measures] were evaluated over 210 min. The results indicate that, despite slightly higher BrAC values for the FHP men, on the SHAS the FHP women and the FHP men demonstrated significantly lower scores than the FHN male controls, although the values for FHP men and women did not differ. On body sway, the FHP men showed evidence of less alcohol-related increases than FHN men, and there was a trend in the same direction for FHP women, but only early in the session (e.g. at 60 min). Pilot data for 11 FHN women revealed higher scores for both SHAS and body sway at 60 min, compared to FHP women, but, perhaps reflecting the small number of subjects, the family history differences were not significant. Overall, the results in FHP women resemble those for FHP men, and suggest that a low level of response to alcohol might also be a characteristic of daughters of alcoholics.

Kinematic characteristics of standing disequilibrium: Reliability and validity of a posturographic protocol

Objective: To investigate retest reliability and concurrent validity of the fundamental measurements made of a posturographic protocol that employs quiet standing to quantify the severity and the nature of patients' postural disturbances. Study Design: Retrospective complete block design. Setting: Geriatric rehabilitation department. Participants: Thirty-six participants (age range, 67 to 86yrs) having normal, moderate, or severe levels of disequilibrium. Methods: Quiet standing was evaluated on three occasions using a three-dimensional motion analysis system and a force platform. Eight testing conditions, designed to vary task difficulty by controlling the contributions of vision, foot proprioception, and base-of-support width, were administered. Main Outcome Measures: Retest reliability of body sway, joint alignment, body position, and motor coordination indicators were evaluated by intraclass correlation coefficients (ICCs). Concurrent validity of protocol measures was evaluated by the prediction of disequilibrium from a stepwise linear discriminant analysis. Results: ICCs indicated high level of retest reliability for all variables but those of motor coordination, which was not influenced by testing conditions. Discriminant analysis resulted in a four-factor discriminator that included measures of body sway, position, alignment, and motor coordination. The derived linear discriminate function correctly classified 96% of the patients' level of disequilibrium. Conclusions: The posturographic protocol has the potential to be a useful tool for evaluating severity and nature of postural instability and the effects of pharmacologic and rehabilitative treatment. Results also indicate that combining direct body measurements with force-plate data has the potential to expose the underlying impairments that cause disequilibrium, determine their pathogenesis, and evaluate compensatory strategies.

Head movement restriction and postural stability in patients with compensated unilateral vestibular loss

Objective: To study whether restriction of head-neck movements improves postural performance in patients with compensated unilateral total vestibular loss. Design: Randomized controlled experimental study. Setting: Laboratory for clinical and experimental vestibular testing at a tertiary referral center. Patients: Fifteen consecutive patients (seven men, eight women, mean age 53 years) at routine follow-up, 6 months after translabyrinthine extirpation of acoustic neurinomas (mean tumor size 13.5mm, range 5 to 25mm). None of the patients had signs or symptoms of central nervous system dysfunction. Intervention: Posturographic tests comparing patients with and without a semirigid neck collar. Test order was randomized between patients to reduce training effects. Main Outcome Measure: Posturography measuring velocity and variance of quiet stance and measuring body sway induced by vibration at 60, 80, and 100Hz to the calf muscles. Tests were conducted with eyes open and closed. Results: In tests with vibration at 100Hz to the calf muscles and with eyes open, body sway velocity was significantly higher when patients were wearing a neck collar. No significant difference was found in any other test. Conclusion: Restricting head-neck movements with a neck collar does not improve postural stability in patients with compensated unilateral total vestibular loss. A tendency toward impaired postural performance leads to the conclusion that it is not appropriate to treat such patients with neck collars to improve their balance.

Repeatability of body sway measurements; day-to-day variation measured by sway magnetometry

The postural stability of 30 normal subjects in the age range 15 to 64 years was measured on five separate occasions, using the sway magnetometry technique, to determine the day-to-day repeatability of this measurement technique. On each occasion the pathlength and area enclosed by movement of the hips in a horizontal plane were measured over two 30 s periods with eyes open and eyes closed, with subjects standing on a firm base. Day-to-day repeatability had a standard deviation of 14% for pathlength and 42% for area. Neither the age nor the sex of the subject had any demonstrable effect on the results. Keywords: balance, posturography, magnetometry, repeatability

The effects of hyperventilation on postural control mechanisms.

The effect of hyperventilation on postural balance was investigated. Voluntary hyperventilation increased body sway in normal subjects, particularly in the sagittal plane. The possibility that this hyperventilation-induced unsteadiness is due to interference with lower limb somatosensory input, vestibular reflexes or cerebellar function was assessed. (i) The effect of hyperventilation on peripheral compound sensory action potentials (SAPs) and somatosensory evoked potentials (SEPs) (recorded centrally, from the scalp) elicited by electrical stimulation of the sural nerve was measured in six normal adults. A reduction in the scalp SEP amplitude and an increase in the peripheral SAP amplitude were observed during hyperventilation, which reversed during the recovery period. These changes indicate increased peripheral neural excitability which could lead to a higher level of ectopic activity; the latter would interfere with central reception of peripheral input. (ii) The click-evoked vestibulo-collic reflex was recorded to study the effect of hyperventilation on vestibulo-spinal activity. EMG recordings from both sternocleidomastoid muscles of six healthy subjects were made in response to loud clicks presented to either ear. Neither the amplitude nor the latency of the response were altered significantly by hyperventilation. (iii) Eye-movement recordings were obtained in the six normal subjects to assess the effect of hyperventilation on the vestibulo-ocular reflex and its visual suppression, the latter being a function largely mediated by the cerebellum; no changes were detected. (iv) Three-dimensional eye-movement recordings and body-sway measurements were obtained in six patients with longstanding unilateral vestibular loss in order to evaluate if hyperventilation disrupts vestibular compensation. In all patients, a horizontal nystagmus either appeared or was significantly enhanced for > or = 60 s after voluntary hyperventilation. Sway was also enhanced by hyperventilation in these patients, particularly in the frontal plane. This study suggests that hyperventilation disrupts mechanisms mediating vestibular compensation. The increase in sway may be, at least partly, mediated by deranged peripheral and central somatosensory signals from the lower limbs. Hyperventilation seems to spare vestibular reflex activity and cerebellar-mediated eye movements.

Intra-subject inconsistencies in quantitative assessments of body sway

Many reports have appeared in which the postural stability of different groups of individuals has been compared by means of body sway measurements. A common quantitative index of body sway is obtained by observing the subject standing still on a force plate and measuring the length of the trajectory of the centre of pressure over the surface of the plate during a specified period of time. We have measured body sway on normal healthy adult subjects. It appears that repeated measurements upon the same individual show a very large spread of values. Many of the subjects did not show consistent results when means of 10 trials each of 1 min duration were measured on consecutive days. We conclude that repeated tests upon a particular individual would have limited value in diagnosis or assessing the progress of a neurological disorder or the efficacy of medication, or therapy, in its treatment. Further, we would be unable to use an individual's value of the body sway to determine reliably whether he falls within a particular group.

Exercise effect on dynamic stability in older women: A randomized controlled trial

Objective: To determine whether a 12-month program of regular exercise can improve dynamic postural stability in older women. Design: Randomized controlled trial of 12 months' duration. Setting: Conducted as part of the Randwick Falls and Fractures Study, in Sydney, Australia. Participants: One hundred and twelve community-dwelling women aged 60 to 85 years (mean age 71.2, SD = 5.4). Outcome Measures: Quantitative measures of dynamic postural stability: maximal balance range and coordinated stability. Main Results: Exercise and control subjects were tested before, midway through, and at the end of the trial. The stability measures had good test-retest reliability, and test performances were significantly associated with measures of lower limb muscle strength, reaction time, neuromuscular control, and body sway. At initial testing, exercisers and controls performed similarly in the two stability measures. The mean number of classes attended for the 48 exercise subjects who completed the program was 58.4 (range 26–77). At the end of the trial, the exercise subjects showed significantly improved performance in both the maximal balance range and coordinated stability tests, with no improvement evident in the controls. Improvements in coordinated stability were associated with corresponding improvements in ankle dorsiflexion, hip extension, and hip flexion strength. Conclusion: These findings show that exercise can significantly improve dynamic postural stability in older persons and elucidate some possible mechanisms by which such improvements may be mediated.

Posturographic Measurement of Body Sway in Survivors of Severe Closed Head Injury

Postural imbalance was measured in 39 survivors of severe closed head injury 7 to 66 months after head injury using a posturographic platform. The results were compared with those derived from age-matched healthy control subjects. Severe postural imbalance, particularly in an anteroposterior direction, was found in 16 patients, whereas 9 patients showed moderate imbalance and 14 patients showed normal results in the posturographic investigation. Low initial Glasgow Coma Scale scores and deep parenchymal brain lesions demonstrated by magnetic resonance imaging were shown to be significant indicators of subsequent severe postural imbalance. The duration of posttraumatic amnesia, the localization and size of cortical contusions and subcortical white matter lesions, on the contrary, were not associated with postural imbalance in the long-term outcome.

Motoric signs of CNS dysfunction associated with alcohol and cocaine withdrawal

Measures of hand tremor and body sway were recorded from 6 alcohol-dependent (AD) and 16 cocaine-dependent (CD) patients after 1, 3, and 12 weeks of verified abstinence. The same measures were recorded from 15 nonpatient control subjects after comparable intervals. Hand tremor was transduced via an accelerometer. Body sway was transduced by a force-sensitive platform. Analyses revealed different patterns of motoric dysfunction in the AD and CD groups. AD patients exhibited enhanced hand tremor during a pointing task and enhanced body sway. Both of these abnormalities remitted with continued abstinence. CD patients exhibited enhanced and unchanging levels of resting tremor across the first 12 weeks of abstinence, but they had normal levels of body sway and action tremor. These results are interpreted as reflicting a subclinical cerebellar dysfunction in recovering AD patients, and a subclinical extrapyramidal dysfunction in the CD counterparts.

Spontaneous body sway as a function of sex, age, and vision: posturographic study in 30 healthy adults.

Detailed neurological examinations and body sway measurements with a stable force measuring platform were carried out on 30 healthy adults between 21 and 63 years of age. The results were analyzed for sex- and age-associated changes with regard to three different sway components (total sway, anterio-posterior sway, lateral sway) and two different conditions (eyes open, eyes closed). Sex-associated differences were highly significant for all sway components in the oldest age group (51-65 years) in which men exhibited more spontaneous postural sway than women in the condition eyes open. With eyes closed these differences increased. Middle-aged men (36-50 years) also exhibited significantly more postural sway than women of the same age. In the condition eyes open especially total sway and anterioposterior sway were increased, whereas in the condition eyes closed total sway and lateral sway were predominantly higher in men than in women. In the youngest age group (21-35 years) no sex-related differences in postural sway were found. Age-associated differences were significant for anterioposterior sway (eyes open) in men, increasing continuously from the young to the middle-aged, and again from the middle-aged to the older age group. Anterioposterior sway in women, on the contrary, did not change with age. Age-associated differences in women were found for total sway (eyes open) and lateral sway (eyes closed). However, the highest values for total sway and lateral sway within the female group were obtained from young women in both conditions eyes open and eyes closed.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer‐analysed EEG and psychometric assessment of two new non‐benzodiazepine tranquillizers in healthy volunteers

AbstractThe effects on CEEG, psychomotor performance and attention of diazepam 10 mg, RU 43028 100 mg, RU 32698 100 mg and placebo administered orally have been investigated in 12 healthy subjects in a double‐blind controlled study. The effects of the compounds were evaluated by objective tests (CEEG, measurement of body sway, critical flicker fusion, visual reaction time, tapping test, arithmetical calculation) and subjective measurements (visual analogue scales and side‐effects questionnaire). Measurements were taken before treatment and after 30 min, 2 h, 3.5 h and 6.5 h. Placebo and RU 43028 did not affect any of the tests used. Diazepam induced an increase in beta rhythms and a decrease in theta and alpha rhythms on CEEG. These expected patterns were correlated with plasma concentrations. It also induced sedative side‐effects characterized by an increase of body sway and reaction time and a decrease of CFF and arithmetical calculation. RU 32698 displayed on atypical profile on CEEG with a reduction of alpha and theta rhythms without changes in beta and delta rhythms. It did not have any psychometric incapacitating effect.

The measurement of body sway

AbstractThe reliability of a direct, contact, mechanical method for the quantification of body sway is assessed. Methodological aspects in measurement of the eyes open/eyes closed ratio are also considered.

VISUAL CONTROL OF BALANCE IN CEREBELLAR AND PARKINSONIAN SYNDROMES

The role of vision in the control of balance in patients with Parkinson's disease (PD) and cerebellar disease (CD) was studied by measuring body sway with eyes open, closed, and in response to visual stimuli generated by discrete lateral displacements of a moveable room which enclosed the subjects. In response to room movement, normal subjects swayed by an amount intermediate between sway with eyes open and eyes closed and their response attenuated on repetition of the movement, a process depending on shifting from predominantly visual to proprioceptive control. CD patients swayed more than controls with eyes open or closed and as shown by high 'Romberg quotients' (eyes closed/eyes open sway ratio) were able to use visual information to control much of their unsteadiness. CD patients had a normal attenuation of response to repetition of the room movement. PD patients had normal sway with eyes open or closed but their responses to room movement were abnormal, being proportionately larger and failing to attenuate during successive stimuli. The results indicate that cerebellar lesions seem largely to spare the visuopostural loop and also spare the ability to shift from a visual to a proprioceptive control of postural sway. In contrast, the findings in PD suggest that the visuopostural loop is hyperactive and that its influence cannot easily be de-emphasized when visual information is misleading. The latter finding suggests that basal ganglia participation in posture is concerned with the reweighting of the various sensorimotor loops controlling posture in the process of adapting to novel situations.

A microanalysis of ethanol-induced disruption of body sway and psychomotor performance in women

Measures of body sway, psychomotor performance and subjective reports of intoxication were obtained from 20 women after consuming either ethanol (0.56 g/kg) or placebo. Simple motor tasks were unaffected by the relatively low ethanol dose. Performance on the Digit Symbol Substitution Test (DSST) was affected only during the ascending portion of the blood ethanol curve while stance stability was disrupted during peak and descending blood ethanol levels. A microanalysis of the dynamic changes of ethanol-induced body sway was conducted and the results plotted in three-dimensional space. These data revealed that disruption of stance stability was more pronounced in the sagittal plane than in the lateral plane and that subjects swayed to the rear and the right side. The results of this study suggest that such data analysis techniques provide extremely sensitive measures of body sway resulting from consuming a moderate dose of ethanol.

Body sway and the effects of psychoactive drugs — a review

AbstractThe published literature on the effects of single oral doses of psychoactive drugs on body sway in normal healthy young volunteers has been reviewed. Several methods are used to quantify sway objectively, including mechanical devices, balance platforms, and non‐contact techniques. No one method emerges as being most appropriate for use in psychopharmacology. Total sway path and Fourier analysis are the variables commonly studied. Although many factors can influence sway they have little impact on well‐designed studies. Ethanol has been consistently shown to increase body sway at doses above 0·5 g/kg, benzodiazepines also increase sway; both probably acting at a central site(s). Various other psychoactive drugs have been shown to increase sway; however, none has yet been shown to decrease the amount of sway in normal subjects. The objective measurement of body sway is therefore a useful test for inclusion in a battery of tests for studies in human psychopharmacology. It also has a potential application in other areas of research requiring the assessment of central nervous system function, and in other subject groups, such as the elderly.

Reactions to alcohol in sons of alcoholics and controls.

This paper synthesizes some major findings coming from our laboratory over the last decade. The data focuses on our search for mechanisms that might contribute to the elevated risk for alcoholism in sons of alcoholic fathers. Consistent results corroborated by several additional groups indicate that the higher risk sons of alcoholics demonstrate less intense reactions to ethanol as measured by their subjective self-reports, measures of body sway, changes in several hormones after drinking, and the intensity or persistence of ethanol-related changes on two electrophysiological measures. The potential implications of these results as they might relate to an enhanced vulnerability to alcoholism, and some possible future research directions, are discussed.

Acute effects of amitriptyline on human performance and interactions with diazepam

The effects of psychomotor performance and attention of amitriptyline 75 mg administered without and with diazepam 10 mg have been investigated in 12 healthy subjects. The effects of the compounds were evaluated by objective tests (measurement of body sway, critical flicker fusion, visual reaction time, tachistoscopy, short term visual memory, tapping test, arithmetical calculation and Clement's code) and subjective measurements (visual analogue scales and side effects questionnaire). Measurements were taken before treatment and after 1, 3, 6, 8 and 24 h. Placebo did not affect either the objective or the subjective measurements. Diazepam caused a reduction in attention and performance after 1 h which had disappeared at 3 h. Amitriptyline caused a marked reduction in attention and performance, reaching a peak 3 hours after drug administration and persisting until 8 h. the deterioration in vigilance induced by amitriptyline was potentiated by concomitant diazepam.

Comparison of the Wright ataxiameter and the Kistler force platform in the measurement of sway

A comparison has been made between two methods of measuring body sway during quiet standing. In the first method a Wright ataxiameter was used to measure the trunk movement in the anteroposterior direction; whilst in the second method a Kistler force platform was used to monitor the locus of the resultant ground reaction force. The good correlation between the two sets of data has resulted in a regression equation to convert one set into the equivalent other set. This equation should be useful while comparing the sway data from various research centres.

POSTURAL BODY SWAY AND EXPOSURE TO HIGH-ENERGY IMPULSE NOISE

Detailed neurological and audiological examinations and body-sway measurements with a stable platform were carried out on 60 subjects who had been exposed to high-energy intermittent noise from firearms and had various degrees of noise-induced hearing loss. The results were compared with those for 115 healthy controls. The exposed subjects showed significantly more body sway, estimated as movement of the centre of gravity in the horizontal plane, than the controls. This swaying correlated poorly with the recalled level of noise exposure, though subjects with more severe hearing loss (by audiometric deterioration of high-frequency sound, 4 kHz and 6 kHz) showed more sway than those with less severe hearing loss. Age was not significantly correlated with body sway among the controls but men seemed to sway more than women. These results suggest subclinical disturbance of the vestibular system among subjects with impulse-noise-induced hearing loss.

マイクロコンピューターを内臓した重心動揺計による平衡機能検査の自動化

An intelligent stabilometer and a stepping test graphical analyzer were devised by the utilization of a microcomputer-powered stabilometer equipped with software for an automatic analysis of the basic stabilo-metry and of the stepping test. The instrument is able to communicate with any host computer through a telecommunication line. Thus, measured raw data can be transferred to the host, and stored in its magnetic storage devices and processed with its unique analyzing software.This means that achievement of the recommendations for stabilometry proposed by the Committee for Standardization of Equilibrium Examinations has easily come within the range of possibility.In the stepping test, measurements and recordings of stepping deviations are automatically performed with higher precision, and the time processes of step-by-step changing stepping deviations are objectively made evident. Furthermore, the possibility of measurement and analysis of body sway during stepping and of the rhythm of stepping is in view.