Postural behaviour responses to visual stimulation in patients with vestibular disorders

Patients with different vestibular disorders exhibit changes in postural behaviour when they receive visual stimuli, reproducing environmental stimulation. Postural control was studied using an AMTI Accusway platform, measuring the confidential ellipse (CE) and sway velocity (SV). Postural responses were recorded according to the following stimulation paradigm: i) without specific stimuli; ii) smooth pursuit with pure sinusoids of 0.2 Hz (foveal stimulation); and iii) optokinetic stimulation (retinal stimuli). Patients with central vestibular disorders (CVD), cerebellar damage and unilateral peripheral vestibular lesions (UPVL) in asymptomatic periods were studied. A group of normal subjects was studied as control. Signal processing was done with a scalogram by wavelets in order to observe the relation between time and frequency in postural control. While patients with CVD and cerebellar disease showed a significant increase in CE and SV in the three conditions of the paradigm compared to the normal group, the patients with UPVL showed no change. Wavelets processing showed that the main sway occurs in the Y axis (antero-posterior) and below at 0.4 Hz in normal subjects, while the CVD and cerebellar patients showed sway frequencies in both the X and Y axes. The clinical implications of these findings are discussed.     

Postural Behaviour Responses to Visual Stimulation in Patients with Vestibular Disorders

Patients with different vestibular disorders exhibit changes in postural behaviour when they receive visual stimuli, reproducing environmental stimulation. Postural control was studied using an AMTI Accusway platform, measuring the confidential ellipse (CE) and sway velocity (SV). Postural responses were recorded according to the following stimulation paradigm: i) without specific stimuli; ii) smooth pursuit with pure sinusoids of 0.2 Hz (foveal stimulation); and iii) optokinetic stimulation (retinal stimuli). Patients with central vestibular disorders (CVD), cerebellar damage and unilateral peripheral vestibular lesions (UPVL) in asymptomatic periods were studied. A group of normal subjects was studied as control. Signal processing was done with a scalogram by wavelets in order to observe the relation between time and frequency in postural control. While patients with CVD and cerebellar disease showed a significant increase in CE and SV in the three conditions of the paradigm compared to the normal group, the patients with UPVL showed no change. Wavelets processing showed that the main sway occurs in the Y axis (antero-posterior) and below at 0.4 Hz in normal subjects, while the CVD and cerebellar patients showed sway frequencies in both the X and Y axes. The clinical implications of these findings are discussed.     

Assessment of the risk of fall, related to visual stimulation, in patients with central vestibular disorders

In order to assess the influence of visual stimulation in the triggering of imbalance and falls in the elderly population, the postural responses of 18 elderly patients with central vestibular disorders and clinical evidence of instability and falls were studied while receiving different types of visual stimuli. The stimulation conditions were: (i) no specific stimuli; (ii) smooth pursuit with pure sinusoids of 0.2 Hz as foveal stimulation; and (iii) optokinetic stimulation (OK) as retinal stimuli. Using a platform AMTI Accusway platform, the 95% confidence ellipse (CE) and sway velocity (SV) were evaluated with a scalogram using wavelets in order to assess the relationship between time and frequency in postural control. Velocity histograms were also constructed in order to observe the distribution of velocity values during the recording. A non-homogeneous postural behavior after visual stimulation was found among this population. In five of the patients the OK stimulation generated: (i) significantly higher average values of CE ( > 3.4+/-0.69 cm2); (ii) a significant increase in the average values of the SV ( > 3.89+/-1.15 cm/s) and a velocity histogram with a homogeneous distribution between 0 and 18 cm/s; and (iii) a scalogram with sway frequencies of up to 4 Hz distributed in both the X and Y directions (backwards and forwards and lateral) during visual stimulation with arbitrary units of energy density > 5. These three qualitative and quantitative aspects could be "markers" of visual dependence in the triggering of the mechanism of lack of equilibrium and hence falls in some elderly patients and should be considered in order to prevent falls and also to assist in the rehabilitation program of these patients.     

Postural control after vestibular schwannoma resection measured with visual feedback posturography

BACKGROUND: Vestibular symptoms after surgery diminish rapidly, but the simultaneous progress in active postural control has not been fully addressed. OBJECTIVES: The aim was to evaluate the progress in postural control in operated vestibular schwannoma (VS) patients with visual feedback posturography (VFP). METHODS: 36 consecutive patients with unilateral VS were studied with the VFP pre-operatively, 1 month and 3 months after the surgery. The accuracy and velocity of active postural control movements to distant targets in VFP was measured and compared to that of healthy controls. RESULTS: The hold percentage within the targets was significantly reduced in the VS patients compared to the controls (pre-operatively p = 0.005; postoperatively at 1 month p = 0.002 and at 3 months p = 0.017). The sway velocity (SV) within the targets among patients with VS was significantly increased pre-operatively (p = 0.009), at the 1-month (p = 0.004) and at the 3-month follow-up visits (p = 0.016). All the postural control parameters except SV tended to improve slightly postoperatively. The consecutive VFP measurements in individual VS patients correlated statistically significantly (p < 0.001 for all parameters). The abnormality in the pre-operative VFP results correlated statistically significantly with that of postoperative VFP (p = 0.001). CONCLUSIONS: The VFP is an objective and repeatable method, which can be used to assess and follow up the active postural control in individual patients with VS. Persisting abnormality in the VFP seems to be an indication for more aggressive vestibular rehabilitation to normalize the disturbed postural control.     

Postural adaptation in elderly patients with instability and risk of falling after balance training using a virtual-reality system

Our aim in this study was to assess postural control adaptation quantitatively in unsteady elderly patients at risk of falls in open spaces and given balance training with a virtual-reality system reproducing environmental stimulation. Using a balance rehabilitation unit based on a virtual-reality system that changes sensory information (visual, vestibular, and somatosensory), we treated 26 elderly, unsteady patients who were prone to falling (age range, 73-82 years) and who were enrolled in a customized vestibular rehabilitation program. We assessed postural responses by posturography before and after 6 weeks in the vestibular rehabilitation program under two conditions: (1) standing, eyes open, static visual field, and (2) standing, eyes open, dynamic visual field through virtual-reality goggles, generating horizontal optokinetic stimulation (70 degrees per second angular velocity). We recorded postural responses with a platform measuring the confidential ellipse of the center-of-pressure distribution area and sway velocity with a scalogram analyzing postural behavior by wavelets. After 6 weeks of treatment, postural response confidential ellipse and sway velocity values were lower, evincing decreased amplitudes and sway frequency contents in the scalogram by wavelet under both stimulation paradigm conditions. These findings suggest postural adaptation under the two perceptual conditions when patients had static and dynamic visual fields. The possibility of treating elderly fallers with balance disorders using a virtual-reality environmental stimulation reproduction system is discussed.     

Balance sensory organization in children with profound hearing loss and cochlear implants

OBJECTIVES: (1) To determine the feasibility of the use of a modified postural control test under altered sensory conditions in children over 8 years of age, and (2) to assess how deaf children use sensory information for postural control when they have normal or abnormal vestibular responses, and if hearing input from a unilateral cochlear implant, changes their postural behavior. PATIENTS: We selected 36 children, 8 to 11 years of age, with congenital or early-acquired profound sensorineural hearing loss, 13 of them with unilateral cochlear implantation and 22 normal-hearing children. METHODS: The Postural Control (PC) test consists of a force platform with 2 stimulation paradigm conditions: (1) standing on the platform with opened eyes; (2) standing on foam placed on the force platform with closed eyes. Implanted children were tested with the implant turn on and turn off in this condition, in order to evaluate eventual change in the postural control parameters when they have hearing habilitation. The body center of pressure distribution area (COP) and the body sway velocity (SV) were the parameter to evaluate the postural control. RESULTS: Deaf children were classified into two groups according with the vestibular responses: group A (n=28) Children with normal vestibular rotary responses; group B (n=8) children with hypoactive responses. Children in group A had diagnoses of syndromic and non-syndromic hereditary deafness, and children in group B had inner ear malformations, post-meningitis deafness, and one child had non-syndromic hereditary deafness with hypoactive vestibular response. In condition 1, when vestibular, somatosensory and visual information were enabled, the COP and SV values did not show any statistically significant differences between groups A, B and control. In condition 2, when visual information was removed and the somatosensory input strongly modified by standing on the foam, group B showed significant higher COP and SV values than groups A and control (p<0.05). In addition, the scalograms by wavelets of children in group B had higher amplitudes increasing the sway frequencies contents up to 3 Hz, not allowing them to maintain the up right stance in similar stimulation than in condition. Implanted children of the group A and B with the implant turn on, in the condition 2, did not show any significant difference in the SV, comparing when they had the implanted turn off. Group A p=0.395 and group B p=0.465 (Wilcoxon ranked test). CONCLUSION: These findings allow us to confirm that this postural test can be performed in children over 8 years old. Also our results suggest that deaf children with associated hypoactive vestibular responses included in our study, despite the etiology of the deafness, primarily use visual and somatosensory information to maintain their postural control. Hearing habilitation with a unilateral cochlear implant has no effect on the observed sensory organization strategy.     

Effect of head orientation on human postural stability following unilateral vestibular ablation.

Effective interpretation of vestibular inputs to postural control requires that orientation of head on body is known. Postural stability might deteriorate when vestibular information and neck information are not properly coupled, as might occur with vestibular pathology. Postural sway was assessed in unilateral vestibulopathic patients before and acutely, 1, 4, and 18+ months after unilateral vestibular ablation (UVA) as well as in normal subjects. Postural equilibrium with eyes closed was quantified as scaled pk-pk sway during 20 s trials in which the support surface was modulated proportionally with sway. Subjects were tested with the head upright and facing forward, turned 45 degrees right, and 45 degrees left. Equilibrium was uninfluenced by head orientation in normal subjects. In contrast, patients after UVA showed both a general reduction in stability and a right/left head orientation-dependent asymmetry. These abnormalities adaptively recovered with time. It is concluded that vestibular inputs to postural control are interpreted within a sensory-motor context of head-on-body orientation.     

Postural stability after vestibular schwannoma surgery

Factors related to postural stability and the course of recovery after vestibular schwannoma surgery were analyzed in a retrospective study of 177 patients and in a prospective study of 44 patients. Before surgery, 7 of the 44 patients in the prospective group complained of postural instability. The body sway velocity was measured. In the retrospective study, the sway velocity was abnormal under nonvisual control in 63% of the patients and under visual control in 34%. The sway velocity correlated with tumor size, smooth pursuit deficit, and postoperative work history. We compared patients with abnormal postural control to those with normal postural control, and found that the former relied to a greater extent on visual information and the latter on proprioceptive information. In the prospective study, the sway velocity increased after the operation, and 1 year after surgery it had not returned to preoperative values. In the logistic regression analysis, a translabyrinthine approach, rehabilitation, the patient's age, and preserved function of the facial nerve predicted a good outcome of postural stability. The retrosigmoid approach and depression were the most significant risk factors for postoperative gait difficulties. Vestibular rehabilitation increased the reliance on proprioception for maintenance of postural control and improved postural stability.     

Subjective visual tilt and lateral instability after vestibular deafferentation

CONCLUSION: Defective utricular function, reflected by deviation of the perceived visual horizontal or vertical, cannot by itself explain increased postural sway in the lateral direction for patients with unilateral vestibular deafferentation (uVD). OBJECTIVE: It is not known why some patients with chronic uVD report distressing unsteadiness while others do not. The objective of this study was to test the hypothesis that impaired utricular compensation, reflected by pathologic tilt in the subjective visual horizontal and vertical (SVH-V) test, would affect postural control in the lateral direction after uVD. PATIENTS AND METHODS: The SVH-V was tested in 28 patients 6 months after translabyrinthine surgery for unilateral vestibular schwannoma, and correlated with posturography results. RESULTS: No increase in lateral and anterior-posterior sway, or the quotients between them, or for Romberg quotients, was found with increasing SVH-V tilt.     

A comparison between oculomotor rehabilitation and vestibular electrical stimulation in unilateral peripheral vestibular deficit

Rehabilitation therapy is proved to be effective in reducing disability in patients with persistent symptoms of disequilibrium after acute unilateral peripheral vestibular deficit. The aim of this study was to evaluate the effects of oculomotor rehabilitation (group 2) on static balance and a dizziness handicap and to compare those with the effects to vestibular electrical stimulation (group 1). Before and after therapy, we tested 28 patients, using static posturography and.the dizziness handicap inventory short form. After therapy, all subjects reported a reduction of symptoms (p = .00019). In group 1, the reductions seen in eyes-opened length of the oscillations and eyes-opened and eyes-closed surface of the body sway were statistically significant, respectively (p = .04; p = .02; p = .02). Group 2 patients revealed better stability on all parameters, and the reductions of eyes-opened length and of eyes-opened correlation function between length and surface were statistically significant (p = .01 and p = .01, respectively). Analysis of the equilibrium system subcomponents did not show any variation. Oculomotor exercises,employed in most rehabilitative protocols and including head movements to improve vestibular adaptation, have proved to reduce the perceived overall impairment and postural sway in patients with recent unilateral vestibular disorders, even though the disorders are not associated with head movements. Comparison of our two study groups did not show any significant difference, revealing that both forms of therapy are effective.     

The diagnosis of central vestibular disorders based on the complementary examination of the vestibulospinal reflex

Objectives:Stance and gait unsteadiness along with vertigo contribute to a central vestibular disorder.For objective analysis ultrasound-computer-craniocorpography(US-COMP-CCG)can be used.Aim of the study was to characterize the unsteadiness in central vestibular disorders and discuss the possible diagnostic usage of US-COMP-CCG.Methods and results:Hundred-and-ninety patients(70 male and 120 female,mean age±SD,58.94±15.27)suffering from central vestibular disorder and 230 healthy control patients(78 male and 152 female,mean age±SD,50.94±15.27)were enrolled.Stance and gait analysis was according to vestibulospinal tests of US-COMPCCG.IBM SPSS V24 software was used for statistical analysis.Mann-Whitney U test and Chi-square test were used,along with sensitivity and specificity categorization.The significance level was p<0.05.According to schematic and statistical analysis instability and postural sway were increased in the vertigo population and statistically significant difference was shown.Upon categorical analysis significant correlation was detected[standing test:longitudinal sway(p<0.00001),lateral sway(p<0.00001),forehead covering area parameters(p=0.0001);stepping test:longitudinal deviation(p=0.05),lateral sway(p=0.011)parameters].Conclusions:Clinicians should consider that postural instability is prominently present in this population and might be of a diagnostic importance.     

Galvanic-induced body sway in vestibular schwannoma patients: evidence for stimulation of the central vestibular system

OBJECTIVE: To investigate the various possible sites of excitation by galvanic stimulation by comparing the galvanic-induced body sway (GBS) in vestibular schwannoma (VS) patients with that in healthy subjects. MATERIAL AND METHODS: This was a prospective experimental study conducted in a tertiary referral centre. In a previous study we developed a standardized procedure for reproducible quantification of GBS using a monaural continuous 1-cosinusoidal stimulus (0.5 Hz; 2 mA). In this study, 23 VS patients were tested before and 12 VS patients were also tested after surgical intervention (extirpation of tumour with concomitant vestibular neurectomy) and the results were compared with those obtained in 47 healthy subjects. RESULTS: There were no significant differences in mean total GBS gain between VS patients and healthy subjects (p>0.05) before surgical intervention. After vestibular neurectomy a significant difference in the mean total GBS gain was observed, but GBS was still present after surgery. CONCLUSION: These results prove that galvanic vestibular stimulation excites the central vestibular system even when conduction via the vestibular nerve is hampered.     

Head sway response to optic flow: effect of age is more important than the presence of unilateral vestibular hypofunction

BACKGROUND: The purpose of this study was to examine how older adults with vestibular impairment use sensory feedback for postural control. METHODS: Nine older adult subjects with unilateral vestibular hypofunction (UVH, mean age 69 y) and 14 older (mean age 70 y) and 8 young adult controls (CON, mean age 28 y) viewed full-field optic flow scenes while standing on a fixed or sway-referenced support surface. The subjects with UVH had 100% caloric asymmetry. Optic flow consisted of sinusoidal anterior-posterior movement of the visual surround at three frequencies and three amplitudes of stimulation. The anterior-posterior head sway was measured. The number of head sway responses that were coupled to the optic flow and magnitude of head sway during optic flow relative to during quiet stance on fixed floor was quantified. RESULTS: The number of trials in which the head sway response was significantly coupled to the optic flow was significantly greater in the Older UVH and Older CON subjects compared with the Young CON subjects. Furthermore, the magnitude of head sway was two to three times greater in Older UVH and CON compared with Young CON subjects. There was no difference in coupling or magnitude of head sway between Older UVH and Older CON subjects. The amplitude of sway was also dependent on the amount of surface support, stimulus frequency, and stimulus amplitude. CONCLUSIONS: Older adults with unilateral vestibular hypofunction who are able to effectively compensate show no difference in postural responses elicited by optic flow compared with age-matched controls.     

2-year review of a novel vestibular rehabilitation program in Montreal and Laval, Quebec

OBJECTIVE: To evaluate the benefits of a vestibular rehabilitation program (VRP) in the Montreal-Laval area. DESIGN: The VRP was conceptualized by a panel of experts including otolaryngologists, physiotherapists, and researchers from McGill University and its teaching hospitals. From February 1999 to December 2001, 117 patients were seen, and 88 of them completed the VRP. SETTING: The VRP has been established at the Jewish Rehabilitation Hospital in Laval, PQ, to provide specialized rehabilitation to clients suffering from vertigo, dizziness, and/or impaired balance owing to lesions or disorders of the vestibular system. Main Outcome Measures: Presence or absence of nystagmus or vertigo during the Dix-Hallpike test, Dizziness Handicap Inventory (DHI), and Dynamic Gait Index (DGI). RESULTS: Thirty-five patients with benign paroxysmal positional vertigo of the posterior canal were treated with canalith repositioning manoeuvres. All of the patients (100%) had absence of nystagmus or vertigo after one to four treatment sessions. Forty-six patients with vestibular deficits or dizziness-disequilibrium completed the VRP, which consisted mainly of individualized eye-head and balance home exercise programs. At the end of the VRP, there was a significant decrease in DHI score (31 vs 57; p < .01) and a significant increase in DGI score (18.4 vs 22.6; p < .01). CONCLUSIONS: A range of modest to major improvements was shown by comparing initial and discharge scores of patients who had completed vestibular rehabilitation. The VRP appears to be beneficial for patients with a variety of vestibular disorders. Further research is needed to continue optimizing vestibular rehabilitation.     

Exercise with visual feedback improves postural stability after vestibular schwannoma surgery

We analyzed the effect of 2-week individualized visual feedback-based balance training on the postural control of patients undergoing retrosigmoid microsurgical removal of vestibular schwannoma. We performed prospective evaluation of 17 patients allocated into two groups: feedback group (9 patients, mean age 37 years) and standard physiotherapy group (8 patients, mean age 44 years). Patients in both the groups were treated once per day by intensive rehabilitation from 5th to 14th postoperative day. Rehabilitation of patients in the feedback group was performed using the visual feedback and force platform. Results were evaluated on the beginning and at the end of rehabilitation program (e.g. 5th and 14th postoperative day). Outcome measures included posturography during quiet stance under four different conditions by the modified Clinical Test for Sensory Interaction of Balance. Body sway was evaluated from center of foot pressure. Compensation of Center of pressure (CoP) parameters in stance on firm surface was similar in the control and feedback groups. However, in stance on foam surface with eyes closed the patients from the feedback group were better compensated and CoP parameters differed significantly (p < 0.05). This prospective clinical study suggests that specific exercises with visual feedback improve vestibulospinal compensation in patients after vestibular schwannoma surgery and thus can improve their quality of life.     

The effect of vestibular rehabilitation supplemented by training of the breathing rhythm or proprioception exercises, in patients with chronic peripheral vestibular disease

OBJECTIVE: To assess the effect of performing vestibular rehabilitation using the Cawthorne & Cooksey exercises supplemented by training of the breathing rhythm or proprioception exercises on self-reported disability and postural control, in patients with chronic, peripheral, vestibular disease. METHODS: Fifty one patients with peripheral vestibular disease and abnormal caloric test participated in the study (mean age 43 +/- S.D. 9 years). They were assigned to one of 3 treatment groups: I. Cawthorne &} Cooksey exercises with training of the breathing rhythm (n=17); II. Cawthorne & Cooksey exercises with proprioception exercises (n=17) and III. Cawthorne & Cooksey exercises with no additional intervention (n=17). The Dizziness Handicap Inventory and static posturography were evaluated prior to treatment and at week 8 of follow-up. RESULTS: Prior to treatment, composite scores on the Dizziness Handicap Inventory and static posturography were similar in the 3 groups. After treatment, a decrease of the composite score of at least 18 points was observed more frequently in patients of the respiration group (94%), compared to the proprioception group (53%) and the Cawthorne & Cooksey group (70%) (p=0.03); while the proprioception group showed a significant decrease of oscillation during all sensory conditions of static posturography (p< 0.05). CONCLUSION: The results suggest that regulation of the breathing pattern may have an influence on disability related to chronic vestibular disease, while proprioception exercises may improve postural control. However, further studies are needed to evaluate if training of the breathing rhythm could be an additional tool for vestibular rehabilitation.     

evaluation of postural stability in patients wit unilateral vestibular hypofunction:effect of feet orientation

To investigate effect of feet orientation on the evaluation of the postural stability in patients with unilateral vestibular hypofunction (UVH) by timed standing tests and static posturography (SPG). Methods 65 subjects with UVH and 92 healthy subjects regarded as control group took the posrural stability tests in four different stances including (1) standard Romberg test, (2) feet-apart stance test, (3) tandem and (4) unilateral standing tests. In each stance, the postural stability was measured in both eyes open (EO) and eyes closed(EC) conditions. The average time that subjects kept balance before falling in each test conditions was recorded by stopwatch as the timed result. In addition, the sway velocity (SV) of center of foot pressure in the upright stance during standard Romberg test and feet apart stance, regarded as postural stability, was also recorded as SPG. Results (1) The balance-maintain-ing time of the UVH group in tandem and unilateral standing with EO and EC was decreased (P< 0.001) compared with the control group. (2) The SVs during standard Romberg test and foot-apart stance withEO were not different between the UVH group and control group (P = 0.118 and 0.110 respectively), but significant with EC condition (P < 0.001). (3) For both groups, the SV during foot-apart standing was shorter than standard Romberg test both with EO and EC(P< 0.05 and P < 0.001). (4) There was no correlation between the balance time and SV for either groups (P > 0.05). Conclusions The results suggest that the tandem and unilateral stance tests may provide additional information about the upright stance to the SPG measurement in patients with UVH. The effect of feet orientation on SPG measurements should be considered.     

The effect of betahistine on vestibular habituation: comparison of rotatory and sway habituation training

This study was designed to investigate the effect of histaminergic agonists and antagonists on the acquisition of vestibular habituation. The experimental animals, pigeons, were subjected to unilateral rotatory and sway habituation training sessions. The habituation of postural reflexes and post-rotatory head nystagmus was assessed. Vestibular habituation in the control group was achieved by adopting the kinetic reflex posture after approximately 9 training sessions, and after 10 and 14 training sessions, respectively for 50% reduction of the total number of beats (TNB) and the duration of post-rotatory head nystagmus. In the sway adaptation test control pigeons needed nearly 15 training sessions while pigeons receiving betahistine adapted after approximately 8 sessions. Administration of histamine and, most notably, betahistine accelerated the process, while both H1 and H2 antagonists (clemastine, cimetidine) tended to retard it, indicating a less significant contribution of H2 receptors. The cholinergic agent physostigmine strongly retarded habituation while the anticholinergic agent scopolamine markedly accelerated it. In addition the adrenomimetic agent ephedrine also accelerated habituation while the adrenolytic agent droperidol retarded reduction of nystagmus beats. The results indicate that histaminergic receptors play a significant role in the vestibular habituation mechanism but are intricately involved with other types of receptors. Betahistine is clearly the agent of choice for attenuating vestibular effects.     

Changes in postural control in healthy elderly subjects are related to vibration sensation, vision and vestibular asymmetry.

The aim of this study was to analyze the composition of sway in adults and "healthy" elderly people and to evaluate the influence of vibration sensation and asymmetric vestibular function on the sway pattern. Ten adults with a mean age of 37.5 years and 40 healthy senior citizens with a mean age of 74.6 years living independently in the community were studied. Vibration-induced body sway was measured on a force platform. The sway was analyzed and separated into its high and low frequency components above and below 0.1 Hz, respectively. Additionally the elderly subjects were observed for the occurrence of spontaneous gaze and head shake-induced nystagmus using infrared charge-coupled device cameras and the vibration perception in the lower limbs was tested with a tuning fork. Vibration perception was the major determinant for postural control in the elderly subjects. Postural control among the elderly subjects with intact vibration perception in their lower limbs was very similar to that of the adults. The elderly subjects with impaired vibration sensation had increased high frequency sway compared to adults and the elderly subjects with intact sensation. Regardless of the strong influence of vibration sensation on postural control, asymmetric vestibular function might also be a contributing factor to postural instability in the elderly. Age per se had little effect on the outcome of the tests except that the elderly subjects had diminished ability to use visual cues to reduce postural sway. We concluded that sensory status in the lower limbs is of utmost importance for postural control in the elderly. Rehabilitation programs for senior citizens should therefore include exercises to preserve recognition of body motion by the lower limbs. Exercises to facilitate vestibular compensation could be useful for elderly people with vestibular dysfunction.     

Posturographic findings in two common peripheral vestibular disorders

Peripheral vestibular pathology disturbs the vestibulospinal reflex in a number of cases. The recording of postural sway furnishes an evaluation of this vestibulospinal influence. Two common peripheral vestibular syndromes were studied: Ménière's disease and peripheral unilateral vestibular hypofunction. It is evident that, by posturography, vestibulospinal disturbance is shown in these peripheral syndromes, whereas its occurrence cannot be predicted by other tests, e.g. caloric and rotation tests. Normalization of the vestibulospinal reflex depends on central adapting mechanisms, which were evidently still incomplete in a number of the cases examined. Whereas abnormal postural results were equally observed in both groups, rotation tests showed better vestibulo-ocular compensation in Ménière's disease, compared to the cases with unilateral vestibular hypofunction. It mattered not whether the Ménière patient was in an active or a stabilized phase. A striking difference was noted for those Ménière patients with atypical vertigo complaints, who showed a high frequency of posturographic disturbances.