Influence of age and gender in the sensory analysis of balance control

Postural control is achieved through the integration at the central nervous system level of information obtained by the visual, somatosensory and vestibular systems. Computerized dynamic posturography and the Sway Star system are both used to carry out sensory analysis. The purpose of this study was to determine the influence of sex and age on sensory analysis, measured with these two systems, and to compare their results. A prospective trial was conducted with 70 healthy individuals (average age: 44.9 years) uniformly distributed in seven age groups, who underwent postural study with both systems. We used SPSS 16.0 for statistical study: comparison of means test for influence of gender and age and Pearson’s correlation test (p < 0.05). Gender variable had no influence. The influence of age in vestibular input was found to be significant with both posturography systems, while visual input was only found to be significant with the Sway Star. The results with the two systems were not comparable. Sensory contribution does not remain stable throughout life. Visual information decreases with age, reaching a minimum at 40–49 years, and may correspond to the deterioration of eyesight with age. Propioceptive information showed no statistically significant changes, and several forms of treatment might correct the deterioration of this system. Vestibular information reaches a maximum in the 40–49 years age group in an attempt to compensate for visual deterioration, and decreases again in subsequent decades. This may be due to aging of the vestibular system and the difficulty in its correction.     

Balance control near the limit of stability in various sensory conditions in healthy subjects and patients suffering from vertigo or balance disorders: impact of sensory input on balance control

The large inter-individual variability within the normal population, the limited reproducibility due to habituation or fatigue, and the impact of instruction and the subject's motivation, all constitute a major problem in posturography. These aspects hinder reliable evaluation of the changes in balance control in the case of disease and complicate objectivation of the impact of therapy and sensory input on balance control. In this study, we examine whether measurement of balance control near individualized limits of stability and under very challenging sensory conditions might reduce inter- and intra-individual variability compared to the well-known Sensory Organization Test (SOT). To do so, subjects balance on a platform on which instability increases automatically until body orientation or body sway velocity surpasses a safety limit. The maximum tolerated platform instability is then used as a measure for balance control under 10 different sensory conditions. Ninety-seven healthy subjects and 107 patients suffering from chronic dizziness (whiplash syndrome (n = 25), Meniere's disease (n = 28), acute (n = 28) or gradual (n = 26) peripheral function loss) were tested. In both healthy subjects and patients this approach resulted in a low intra-individual variability (< 14.5(%). In healthy subjects and patients, balance control was maximally affected by closure of the eyes and by vibration of the Achilles' tendons. The other perturbation techniques applied (sway referenced vision or platform, cooling of the foot soles) were less effective. Combining perturbation techniques reduced balance control even more, but the effect was less than the linear summation of the effect induced by the techniques applied separately. The group averages of healthy subjects show that vision contributed maximum 37%, propriocepsis minimum 26%, and labyrinths maximum 44% to balance control in healthy subjects. However, a large inter-individual variability was observed. Balance control of each patient group was less than in healthy subjects in all sensory conditions. Similar to healthy subjects, patients also show a large inter-individual variability, which results in a low sensitivity of the test. With the exception of some minor differences between Whiplash and Meniere patients, balance control did not differ between the four patient groups. This points to a low specificity of the test. Balance control was not correlated with the outcome of the standard vestibular examination. This study strengthens our notion that the contribution of the sensory inputs to balance control differs considerably per individual and may simply be due to differences in the vestibular function related to the specific pathology, but also to differences in motor learning strategies in relation to daily life requirements. It is difficult to provide clinically relevant normative data. We conclude that, like the SOT, the current test is merely a functional test of balance with limited diagnostic value.     

应用海绵垫干扰本体觉分析正常人姿势平衡中的感觉整合作用

目的：探讨正常人直立于坚硬平板和海绵垫时,视觉、本体觉和前庭觉在维持姿势平衡中的整合作用。方法：106名正常人分别站立于坚硬平板和海绵垫上,每种站立在平面条件下,睁眼和闭眼各站立30s。分别记录不同感觉干扰条件下足底压力中心平均晃动速度（SV）,作为姿势稳定性的参数,并定量分析视觉、本体觉和前庭觉在维持姿势平衡中的整合作用。结果：①在视觉或（和）本体觉受到干扰时,SV均增加,其差异有统计学意义（P〈0．01）;②当本体觉未被干扰及被干扰时,视觉条件的变化引起SV增加程度分别是（12．12±6．19）％和（30．58±9．69）％;当视觉条件未被干扰及被干扰时,本体觉变化导致的SV增加程度分别是（18．31±6．56）％和（36．25±8．90）％;而当视觉和本体觉同时受到干扰时,SV增加程度是（46．21±8．67）％;③在姿势平衡中起作用较大的是前庭觉,其次是本体觉和视觉,三者呈非线性关系。结论：利用海绵垫干扰本体觉,结合姿势描记可以记录不同感觉条件下姿势稳定性,并可定量分析视觉、本体觉和前庭觉在姿势平衡中的整合作用;人体维持平衡过程中,应用3种外周感觉的姿势策略差异较大;当1种或2种外周感觉信息被干扰时,中枢神经系统为维持姿势稳定,存在复杂的感觉整合机制。     

Nasal response to stress test in healthy subjects: an experimental pilot study

European Archives of Oto-Rhino-Laryngology - Stress has been suspected to play a role in rhinitis. The role of stress on nasal patency has been not yet elucidated. The aim was to evaluate the...     

Effects of oxymetazoline on the ventilation of paranasal sinuses in healthy subjects

BACKGROUND: Impairment of sinus ostial function is considered an important factor in the pathophysiology of sinus disease. The use of the decongestants such as alpha2-agonists is thought to improve sinus ostial function. Previous studies have shown an effect of alpha2-agonists on maxillary sinus ostial function only when administered in nasal bellows, but not as a nasal spray or nasal drops. The effect of decongestants on ventilation of the frontal and posterior ethmoidal and sphenoidal sinuses has not been studied to date. METHODS: In this study, the 133-xenon washout method was used to determine ventilation for all paranasal sinuses before and after administration of oxymetazoline as nasal drops in eight subjects and from nasal bellows in nine healthy subjects. RESULTS: No significant effect of oxymetazoline on sinus ventilation was seen in either group. CONCLUSIONS: The results indicate that alpha2-agonists do not have any effect on sinus ventilation in healthy subjects. However, one cannot exclude that decongestants improve sinus ventilation in patients suffering from sinus disease and this requires further studies.     

Influence of gender on the vestibular evoked myogenic potential

There is no consensus on the relevance of factors that influence gender differences in the behavior of muscles. Some studies have reported a relationship between muscle tension and amplitude of the vestibular evoked myogenic potential; others, that results depend on which muscles are studied or on how much load is applied.AimsThis study aims to compare vestibular evoked myogenic potential parameters between genders in young individuals.MethodsEighty young adults were selected - 40 men and 40 women. Stimuli were averaged tonebursts at 500 Hz, 90 dBHL intensity, and a 10-1000 Hz bandpass filter with amplification of 10-25 microvolts per division. The recordings were made in 80 ms windows.Study typeAn experimental and prospective study.ResultsNo significant gender differences were found in wave latency - p = 0.19 and p = 0.50 for waves P13 and N23, respectively. No differences were found in amplitude values - p = 0.28 p = 0.40 for waves P13 and N23, respectively.ConclusionThere were no gender differences in latency and amplitude factors; the sternocleidomastoid muscle strain was monitored during the examination.     

Circadian variation of nystagmus in healthy and sick subjects

Rhythmic activity of various biological systems and functions have been investigated extensively. However, information about diurnal variations of the vestibular system is scarce. In the present preliminary report, diurnal variations of the spontaneous and induced nystagmus in healthy subjects and in patients with peripheral vestibular disorders have been assessed. Circadian rhythms of the vestibular responses were demonstrated. In some variables significant differences have been found between health and sick examinees. These differences may have practical clinical implications on diagnosis and treatment.     

The limits of stability in patients with unilateral vestibulopathy

Objective: To characterize the stability limits and region in patients with unilateral vestibulopathy according to the side of the lesion and determine if that imposes any bias. To analyze if the stability limits and region depend on the functional deficit as evaluated in the sensory organization test.

Methods: Forty patients with chronic dizziness and without any vertigo spell for least 6 months prior to testing. In all of them, a unilateral vestibulopathy was diagnosed clinically and at vestibular testing. A computerized dynamic posturography system was used to test for the ability of patients and controls to displace their center of pressure (COP) to the corresponding LOS. The area was calculated and compared to other data from vestibular tests.

Results: The area of stability among patients shows a reduction to 35–62% of the expected total. That reduction was not found to be dependent on age.

Conclusion: There is a symmetric reduction in the limits of stability (LOS) in patients with unilateral vestibulopathy who suffer chronic instability. None of the areas measured were correlated with the composite score of the sensory organization test and, as such, must be considered as an adjunct measure to characterize the postural limitations in those patients.     

Positional and positioning nystagmus in healthy subjects under videonystagmoscopy

OBJECTIVE: The eye-focused video camera as sensitive to infrared light is very useful for detecting nystagmus with open eyes in the dark. The existence of physiological nystagmus has been reported. We investigated how frequently physiological positional and positioning nystagmus is seen in healthy individuals under infrared video goggles. MATERIALS AND METHODS: Eighty-nine healthy individuals were examined in this study. Positional and positioning nystagmus was examined with infrared video goggles. RESULTS: Positional nystagmus could be detected in 65 of the 89 subjects under infrared video goggles. The majority of nystagmus was horizontal nystagmus, and vertical nystagmus was also seen in four subjects. Nystagmus was most frequently recognized in right or left shoulder down position. Positioning nystagmus was detected in 40 subjects. CONCLUSIONS: Positional and positioning nystagmus frequently exist in healthy subjects. This finding means that the existence of physiological nystagmus must be considered when diagnosing dizzy patients using this equipment.     

Effects of sustained-release oral phenylpropanolamine on the nasal mucosa of healthy subjects

Phenylpropanolamine (PPA) is widely used as a nasal decongestant administered orally in sustained release preparations and, in Sweden, the recommended dose nowadays is 50 mg twice daily for adults. The aim of this placebo-controlled, cross-over study was to determine the onset and duration of the decongestive effect of 50 and 100 mg PPA in 15 healthy subjects. All subjects arrived at the laboratory at 07.30 h. After an acclimatisation, the nasal mucosal baseline was established with rhinostereometry and the minimal cross-sectional area was measured using acoustic rhinometry. The systolic and diastolic blood pressures were also determined. Then all subjects were given their study drugs for the day and the measurements were repeated every hour for 8 h. This procedure was repeated for 3 days at 48 h intervals between the days. For purposes of comparison, the decongestive effect of oxymetazoline nasal spray was studied on a separate day. The decongestive effect of 100 mg PPA was similar to that of topical oxymetazoline. It develops after 1 h and lasts for approximately 6 h. The decongestive effect of oxymetazoline was significantly greater than that of 50 mg PPA and that of 100 mg PPA was significantly greater than that of 50 mg PPA using rhinostereometry, but not when using acoustic rhinometry. However, 50 mg PPA had no significant decongestive effect, compared with placebo, with rhinostereometry or acoustic rhinometry. In the first 3 h after administration of PPA, there was a dose-response increase in the systolic and diastolic blood pressures, which then returned to baseline. In conclusion, this study shows that PPA in double the recommended dose, i.e. 100 mg, has a significant decongestive effect on the nasal mucosa in healthy subjects. However, when the dose of PPA is increased the systolic and diastolic blood pressures also increase.     

Activation of the nasal cilia. Preliminary study in healthy subjects

The effect of the drug HR-6 containing adenosine triphosphate in three concentrations and of a placebo on nasal mucociliary function was studied in sixteen healthy subjects. Nasal mucociliary function was measured on both sides of the nose with a radioisotopic method before and after the drug administration. The nasal mucociliary transport rate was increased by the active drug, on the average, by 2.0-3.2 mm/min in all three concentrations and by 0.2 mm/min in the placebo group, when one side of the nose was taken into account. When the average of the mucociliary function rate on both sides of the nose was calculated, the active drugs were found to increase the transport rate from 6.0 to 8.9 mm/min. The results of this preliminary study indicate the need for further studies in patients with impaired mucociliary function.     

Comparative study of computerized dynamic posturography and the SwayStar system in healthy subjects

Conclusion. Excluding the possibility of acoustic neuroma, therapeutic benefits from dextran 40 can be anticipated in a pregnant woman with sudden deafness, leading to significant hearing improvement, without detrimental effect on the mother or fetus. Objective. The aim of this study was to present our experience in the treatment of pregnant women with sudden deafness during the past decade. Methods. From January 1994 to December 2003, 12 pregnant women with sudden deafness were consecutively encountered at the authors’ clinic. With the exception of one patient with acoustic neuroma who underwent craniotomy, six patients were treated with dextran 40 only, while the other five patients preferred no medication, and served as a control group. Each patient underwent audiometry before treatment and at 1 year postpartum. Results. In the dextran group, five (83%) of six patients had hearing improvement 1 year postpartum, compared with one (20%) of five patients in the control group showing hearing improvement; both groups revealed a significant difference. Those receiving intravenous dextran treatment had significant hearing improvement at the frequencies of 1000, 2000, and 4000 Hz, at 1 year postpartum. In contrast, in those who followed a natural course without medication no significant difference existed in the mean hearing level of each frequency, at 1 year after delivery.     

Morphological radioautographic study of the palatine tonsils in chronic tonsillitis and healthy subjects

A pilot morphological (radioautographic) study of healthy and affected palatine tonsils (in hypertrophy and toxic-allergic form of chronic tonsillitis) in children and adults has shown that intensity of biosynthetic processes (protein-synthetic -- RNA synthesis and proliferative activity -- DNA synthesis) in the cells of palatine tonsils and structural changes of their tissues depend on characteristics of pathological process. Microbial penetration into the tonsils with formation of an active focus of chronic infection is traced.     

Spontaneous and provoked nystagmus in healthy subjects: on the so-called "vestibular" form

A total of 25 healthy subjects were available for the study of provoked nystagmus using a series of vestibulometric functional tests affecting different component of the vestibular system. The study has demonstrates the high diagnostic value of provoked nystagmus and the importance of a series of vestibulometric functional tests as a tool for the evaluation of vestibular reactivity. Provoked nystagmus was documented in 3 cases using the full series of functional tests and was absent in 9 cases under the same conditions. It is concluded that observation of provoked nystagmus in individual tests reflects its etiology whereas its occurrence in the entire series of these tests suggests diagnosis of latent vestubular dysfunction.     

Vestibular velocity step test and normal limits for the Chinese]

Vestibular velocity steps test (VVST) to impulsive stimulus of horizontal rotation (90 degrees/S and 180 degrees/S) were performed in 22 normal subjects. Gain (G) was defined as the ratio of the initial slow phase eye velocity (ISPV) to head velocity. The time constant (T) was the time to find the point where it was 0.37 of ISPV. Duration (D) of induced nystagmus was the time between first and final nystagmus. The directional preponderance (DP) for G, T and D was calculated from the formula, (R-L)/(R+L) x 100%. These normal limits were 0.37-1.09 and 0.27-0.83 for G, 8.0--20.4s and 6.5-17.3s for T, 30.4-65.0s and 30.0-54.4s for D, +/- 21.4% and +/- 21.5% for DP(G), +/- 24.2% and +/- 20.3% for DP(T), +/- 16.5% and +/- 17.9% for DP(D) of 90 degrees/S and 180 degrees/S, respectively. The advantages and shortcomings of VVST and its value were discussed.