INTRODUCTION

Vestibular system, together with visual and proprioceptive systems, is responsible for body balance. Sensorial information from these systems, integrated by Central Nervous System, determines the maintenance of body balance. Central Nervous System performs the integration from visual sensorial, vestibular and proprioceptive information in specific centers placed on brainstem and cerebellum, and also determines head, neck, vertebral column, legs, arms, eyes movements and all body muscles, which are needed to guide and keep it in balance1.

Vestibular system disorders can present symptoms such as vertigo and other types of dizziness or unbalance, mainly on adults and elderly people, affecting specially females 2,3,4.

Body unbalance and other types of dizziness come from the non-integration from vestibular, visual and proprioceptive information received by central nervous system. Balance disorders (non-rotatory dizziness and vertigo- rotatory dizziness) are common symptoms on peripheral or central vestibulopathy. Vertigo is normally followed by neurovegetative symptoms such as nausea, vomit, intense sudoresis and paleness2. Feelings of undulatory movement, oscillation, body swinging and fluctuation are reported as dizziness3. Tinnitus, hypoacusis, feeling of pressure on the head, hypersensitiveness to sounds, weakness, falls, headaches, sight darkening, difficulty of eye fixation, sleep disorders, difficulty when concentrating, memory confusion, visual hallucination, anxiety, depression and phobias are also reported as dizziness2,3, by patients.

Otoneurological evaluation, which covers audiological and vestibular evaluations, allows the functioning characterization of hearing and vestibular systems and their relations with Central Nervous System. It also aims to promote the localization of peripheral lesions (labyrinth and pair VIII) and/or central lesions (nucleus, passages and interrelation with central nervous system) 2,3,5. Currently, computed vectoeletronystagmography is the main evaluation method for vestibular system evaluation. It precisely measures the parameters of oculomotor-vestibular function an presents larger sensitiveness when identifying signs of vestibular implications6,7.

Antivertigo medication is one of the ways used for vestibular disfunction treatment. This type of medication can change the results of vestibular and oculomotor tests which compose otoneurological evaluation when accomplishment without dismissing them, as vestibular system is sensitive to several medication effects2,8. Some studies suggest that different substances can change eye movement2,9. Sedatives, antiemetics, anti-histaminics are used to ease vertigo symptoms and then suppress vestibular ocular reflex (VOR), observing suppression of nystagmus speed inducing in caloric terms during vestibular evalutation9,10,11. Therefore, vestibular exam should be done without using non-essential medication such as antivertigo, tranquilizers, anticonvulsion, narcotic, anti-histaminics, antiemetics and antiallergics, because they can excite or inhibit vestibular function8,12.

The target of this study was to compare the results from caloric tests from patients submitted to vestibular evaluation with and without antivertigo medication use.


METHODS

29 subjects were examined, 20 women and 0 men, aging between 20 and 77 years, with average age of 54.24 years. They were selected from a list of patients assisted at Otoneurology ambulatory - CEFAC. They had already done vestibular exam without antivertigo medication and returned to new evaluation with such medication use. They were informed on the purpose of this research, and agreed to sign a free and clear consent document for inclusion. The exams were done at Otoneurology ambulatory - CEFAC through computed vectoeletronystagmography, done with a digital Neurograff, with specific software (Vec-win). To do caloric test, it was used NGR05 Neurograff air, considering the standard rules previously established 12,13.

Otoneurological evaluation consisted of vestibular exam with the following tests: research of posicional nystagmus, calibration of eye movement, research of spontaneous nytagmus with open and closed eyes, research of semi-spontaneous nystagmus, research of saccadic movements, research of pendular tracking at a speed of 0.10Hz, 0.20Hz and 0.40HZ, research of optokinetic nystagmus and research of post-caloric nystagmus through caloric test with air at 42°C e 18°C. In this study we decided to compare only the responses from the research of post-caloric test due to the fact that it is a specific evaluation of vestibular function and it allows to evaluate each of the labyrinth separately4,5,9. In this study we decided to compare only the responses from the research of post-caloric test due to the fact that it is a specific evaluation of vestibular function and it allows to evaluate each of the labyrinth separately4,5,9. For this study, it was chosen the individuals whose first exam presented Irritative Peripheral Vestibular Syndrome (IPVS) or Deficient Peripheral Vestibular Syndrome (DPVS) as a result and were also taking antivertigo medication, at least for 30 days, under medical orientation. The exams taken as (IPVS) presented DP (directional preponderance) > 22% or hyperreflexia (angular speed of the slow component >19º/s) and the ones taken as DPVS presented LP (labyrinthine predominance) > 33% or hyporreflexia. (Angular speed of the slow component >2º/s) 12,13. All individuals did the first vestibular exam under previous diet and without antivertigo medication use. The medication used by patients on the second exam was: cinarizine dichloridrate, flunarizine dichloridrate, Betahistine dichloridrate and Ginkgo-biloba Egb-761 extract.

The statistic methods used were: Student-t test for paired data, Qui-square test and Mann Whitney test. Student-t test was controlled by Levene test for equality of variances, with the purpose of verifying the differences between age averages of the genre group. The level of significance was 5% (0.050) to statistical test application.

This study was evaluated and approved by Comitê de Ética em Pesquisa (Ethics Committee) of the Specialization Center on Clinical Phonoaudiology, nº 167/03. And it was considered riskless and with the need of free and clear consent (Annex 1).


RESULTS

It was done a comparative statistical analysis of the group whose individuals were under evaluation A (no medication use) and evaluation B (medication use), using Mann Whitney test, relating sex and age, IPVS and SVPD exam results and sex and changes of post-caloric responses (angular speed of the slow component of the nystagmus) between sexes. This analysis had the purpose of verifying possible differences between the age averages and differences between exam results from both groups, male and female. It was found that there are no statistical differences and, so, data were analyzed together.

The group who took part of this study was formed by 17 individual with IPVS and 12 with DPVS, considering alterations presented on caloric tests.

Qui-Square test was applied in order to analyze possible differences of exam results between situations A and B. From this Table we can observe that from the 17 (58.6%) individuals with IPVS in situation A, 12 (41.4%) kept the same result, 5 (17.2%) presented normal exam and none presented deficient exam in situation B. Therefore, from the 12 (41.4%) individuals with DPVS in situation A, 3 of them (10.3%) had unaltered results, 3 (10.3%) presented result of irritative exam and 6 (20.7%) had their exams in normal condition in situation B, that means, 50% of the individuals with DPVS presented expressive improvement in evaluation with antivertigo medication.

From this Table, we can observe that 44.4% of the patients who used Cinarizine/Flunarizine dichloridrate presented an increase of vestibular response. Only 01 case (11.2%) when patient presented IPVS, it was observed a reduction on angular speed of the slow component of the nystagmus, making vestibular exam normal.

From this Table it is possible to observe that on cases which Ginkgo Biloba were managed, 51.1% still presented IPVS even after medication use. From cases with DPVS, 7.2% of patients had normal exam and 14.3% presented an increase on angular speed of the slow component of the nystagmus on second evaluation.

From this Table, we can observe that from the 06 cases with medication use, 02 of them (33.2%) kept result of IPVS and 02 (33.2%) had an increase of responses making patients with DPVS have normal or irritative diagnosis.

Student-t test was used to paired data on the comparative analysis of values of angular speed of the slow component of the nystagmus and it was found that statistically expressive changes between situation A and B, from which it was observed an increase of post-caloric responses on stimulation with cool air on right ear (A and B) and hot air on left ear (A and B). On these situations we have nystagmus beating to left.

N Values presented in this Table do not correspond to the 29 selected individuals, though, in some cases, it was not possible to do the four caloric stimulations (42°C RE and LE and 18°C RE and LE) due to neurovegetative manifestations presented by patients. In these cases, the exam was interrupted without any loss on its conclusion, as it already characterized an Irritative Peripheral Vestibular Syndrome (IPVS).


DISCUSSION

The comparative analysis by sex of the studied group in situations A and B was not statistically expressive, though it is important to point out the existence of a sex-related heterogeneous group, in which women predominate. Previous studies reported that vertigo and its associated symptoms are very common among women. This might be due to larger labyrinth susceptibility to functional alterations to distance, and it can be influenced by other clinical disorders from different places and origin, causing hearing and/or vestibular symptoms such as hormone and/or metabolism associated variations with migraine, in which it is observed a greater occurrence in women, and other diseases which make vestibular function5,14,15,16,17,18 sensitive.

The expressive improvement from deficient exams (Table 1) done with medication use as well as the increase on responses of post-caloric nystagmus observed on comparative analysis between situations A and B (Table 2) show that meticulous action can interfere on responses due to its therapeutic action. This action is recommended as a provider of an increase on vestibular function, making vestibluar19 compensation easier. There are reports attesting that some medication acts in a way of stabilizing specific neurotransmitters or increasing cerebral flow and neuronal metabolism7,9,14,19. Among all drugs reported for treatment of patient with vertigo, the most used ones from which good results are achieved are: flunarizine, cinarizine, betahistine, clonazepam, ginkgo biloba and pentoxifiline from which only the last one and clonazepam is not part of this study14,19,20,21,22,23.

Cinarizine and flunarizine have a powerful vestibular suppressor effect, reducing labyrinth excitability due to its peripheral and central antivasoconstrictor action20,21,22,23,24,25. In the analyzed cases (Table 3) we observed an increase of responses in 50% from patients with DPVS submitted to this medication use and only 1 case of reduction on angular speed of the slow component of the nystagmus.

In relation to Ginkgo Biloba EGb 761 extract, the studies report its vasoactive, antioxidant and anti-ischemic properties, which favor blood flow on labyrinth microcirculation and on central nervous system (CNS) 20,21,22,23,24,25. In the cases which Ginkgo Biloba were managed (Table 4), 57.1% still presented IPVS even after medication use.

Betahistine is normally used on treatment of peripheral vestibular disorders. It has an inhibitor and facilitator effect on lateral and medium vestibular nuclei. It also provides an increase of vestibular-cochlea bloody flow20,21,22,23,24,25,26,27,28,29. A reduction of nystagmus duration on Decreasing Pendular Rotation Test occurs when medication is used, what differs from the situation analyzed in this study, where caloric test analysis had the preference30. From the 6 cases which used medication (Table 5), only 1 of them presented a reduction on angular speed of the slow component of the nystagmus, making patients with IPVS have normal diagnosis in the second situation.

Knowing the medication use effects, it is important to consider the need of a vestibular evaluation without it, as medication can interfere on the results, altering its authenticity. Vestibular evaluation should be done, if possible, without any action from substances that are sensitive to labyrinth.


CONCLUSION

1. From the result analysis, we can conclude that caloric test on vestibular evaluations with DPVS done without medication use, suffered a diagnosis change to normal condition in 50% of the examined cases with medication use.

2. We also observed an increase of responses of angular speed of the slow component of the nystagmus on exams done with medication use when compared to the exam done without medication from the same subject.


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1. Master (Phonoaudiology).
2. Post Graduation (Phonoaudiology).
3. Post Graduation (Phonoaudiology).

Centro de Especialização em Fonoaudiologia Clínica - CEFAC (Specialization Center on Clinical Phonoaudiology).
Address: Rua Cayowaá, 664 - Perdizes - CEP: 05018-000 São Paulo - SP

This article was submitted to SGP - Sistema de Gestão de Publicações (Publication Management System) from RAIO on January 22, 2006 and was approved on January 27, 2006 22:30:22.