Lilian Felipe

Interpretação e utilidade da prova calórica

A prova calorica e o teste da avaliacao otoneurologica que verifica a integridade do reflexo vestibulo-ocular e possibilita avaliar cada labirinto separadamente. Os principais aspectos relacionados a realizacao, interpretacao e utilidade da prova calorica foram revistos. METODOS: Realizou-se revisao sistematica sobre as publicacoes ocorridas nos ultimos cem anos sobre o assunto. Incluiram-se artigos originais transversais e longitudinais, de revisao e meta-analise. Excluiram-se revisoes de papeleta, relatos de caso e editoriais. Os descritores utilizados foram: prova calorica, nistagmo, sistema vestibular, preponderância direcional, predominio labirintico, teste calorico monotermal, teste calorico com agua gelada, fenomeno de Bell. Pesquisou-se as bases de dados COCHRAINE, MEDLINE, LILACS, CAPES. RESULTADOS: De 818 resumos de artigos, selecionou-se inicialmente 93 que preenchiam os criterios de inclusao. A leitura dos artigos resultou na selecao final de 55. Na analise dos artigos, enfatizou-se na discussao fundamentos da prova calorica, tipos de estimulacao utilizados, prova calorica monotermal e com agua gelada, questoes relacionadas a interpretacao dos resultados, variaveis e artefatos. COMENTARIOS FINAIS: os valores de referencia utilizados na prova calorica podem variar de servico para servico, com ponto de corte definido a partir de estudos locais. Semiotecnica cuidadosa e fundamental para elevar a sensibilidade do exame.

Interpretation and use of caloric testing

UNLABELLED Caloric testing is an otoneurologic evaluation of the status of the vestibular-ocular reflex; it allows an evaluation of each labyrinth separately. The main aspects on the use and interpretation of caloric testing are reviewed. METHOD A systematic review of papers published in the past one hundred years on caloric testing was undertaken. The inclusion criteria were: cross-sectional, longitudinal, original articles, reviews and meta-analyses. Reviews of patient charts, case reports and editorials were excluded. The key-words were: caloric testing, nystagmus, vestibular system, directional preponderance, labyrinth predominance, monothermal caloric test, ice water caloric testing, Bell s phenomenon. The databases were: COCHRAINE, MEDLINE, LILACS, CAPES. RESULTS Ninety-three of 818 abstracts fulfilled the inclusion criteria. After reading these articles, 55 were selected for this study. These papers discussed the basics of caloric testing, the types of stimulation, the interpretation of results, variables, artifacts, and the monothermal and ice water caloric test. FINAL COMMENTS Caloric testing reference values may vary according to each unit; the the cutoff point is defined based on local studies. Attention to the technique is essential to maximize test sensitivity.

Presbivertigem como causa de tontura no idoso

BACKGROUND dizziness is a frequent complaint in the geriatric population and has a negative impact in the life quality of these individuals. AIM to correlate the types of dizziness and alterations in the caloric test and to verify the frequency of presbyvertigo in an elderly population with dizziness. METHOD The records of 132 patients aged over 60 and with balance disturbance were reviewed. These patients were evaluated in the Otoneurology Service of the Clinical Hospital of the Federal University of Minas Gerais between the years of 1998 and 2007. The variables considered for analysis were: epidemiologic data, clinical history, associated diseases and the result of the caloric test. Patients with positional and central vertigo were excluded from the analysis. RESULTS The research sample consisted of 120 patients, with an average age was of 70 years, being 71% (n=87) of sample women. Vertigo with the duration of a few minutes and of a daily frequency was the most frequent type of dizziness. In relation to the caloric test, normal results were observed in 73% of the sample. Altered results included unilateral weakness (14%), bilateral weakness (10%) and hyperactive caloric response (3%). Correlating the caloric test with the type of dizziness, bilateral weakness was associated with postural instability (p=0.006; IC=2 - 419). CONCLUSION dizziness in elderly has many causes. Bilateral weakness of the vestibular function can be related to presbyvertigo and must be considered in aged individuals who present unbalance. Metabolic, psychiatric, disautonomic, orthopedic, visual and proprioceptive disturbances may be the cause of dizziness in aged individuals who present normal vestibular evaluation.

Potencial evocado miogênico vestibular (Vemp): avaliação das respostas em indivíduos normais

BACKGROUND the Vestibular Evoked Myogenic Potential (Vemp) is formed by myogenic neurophysiologic responses activated by high-intensity sound stimulation. The response is registered through surface electromyography of the cervical muscles during muscle contraction. The acoustic stimuli activate the saccular macula, the vestibular inferior nerve and the pathways related to the vestibule-spinal descendant nerves. AIM to describe Vemp parameters in a normal population. METHODS thirty adults, 13 men and 17 women with no otoneurological complaints were selected. The stimuli were 200 tone burst, with a frequency of 1Hz and intensity of 118 dB Na, band-pass filter ranging from 10Hz to 1500Hz. The first potential biphasic P13-N23 wave was analyzed. RESULTS no significant difference was observed between the sides of stimulation in terms of latency and amplitude. However, a statistically significant difference was found for amplitude between genders. CONCLUSION Vemp demonstrated to be a reliable instrument in the clinical assessment of the vestibular function.

Vestibular-evoked myogenic potential (VEMP) to evaluate cervical myelopathy in human T-cell lymphotropic virus type I infection.

Study Design. Cross-seccional analysis. Objective. To define the clinical usefulness of vestibular-evoked myogenic potential (VEMP) in detecting cervical medullar involvement related to human T-cell lymphotropic virus type 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP). Summary of Background Data. VEMP is generated by acoustic or galvanic stimuli, passing through the vestibulo-spinal motor tract, the spinal nerves and recorded by means of surface electrodes on the sternocleidomastoid muscle. HAM/TSP is a progressive inflammatory myelopathy with predominant lesions at the thoracic spinal cord level, although the cervical spine can be affected. VEMP may be of value to investigate cervical myelopathy. Methods. Seventy-two individuals were evaluated of whom 30 HTLV-1 were seronegative and 42 HTLV-1 seropositive (22 asymptomatic, 10 with complaints of walking difficulty without definite HAM/TSP and 10 with definite HAM/TSP). VEMP was recorded using monaural delivered short tone burst (linear rise-fall 1 millisecond, plateau 2 milliseconds, 1 KHz) 118 dB NA, stimulation rate of 5 Hz, analysis time of 60 milliseconds, 200 stimuli, band pass filtered between 10 and 1.500 Hz. Results. VEMP was normal in the seronegative group (30 controls). In the seropositive, abnormal VEMP was seen in 11 of 22 (50%) of the HTLV-1 asymptomatic carriers, in 7 of 10 (70%) of those with complaints of walking difficulty and in 8 of 10 (80%) of the HAM/TSP patients. In this last group, the pattern of response was different. No VEMP response was more frequent when compared with the HTLV-1 asymptomatic group (2-tailed P-value = 0.001). Conclusion. VEMP may possibly be useful to identify patients with cervical myelopathy and to distinguish variable degrees of functional damage. Minor injury would be related to latency prolongation and major injury to no potential-evoked response.

Avaliação do efeito da cafeína no teste vestibular

Ha controversias sobre a interferencia da cafeina no teste vestibular. O cafe e a fonte mais rica em cafeina. Enquanto em alguns servicos os pacientes sao orientados a suspender a ingestao de cafe 24 a 48 horas antes da realizacao do teste, outros nao consideram necessaria a suspensao da ingestao dessa bebida. OBJETIVO: Avaliar o efeito da cafeina no resultado do teste vestibular. FORMA DE ESTUDO: clinico com coorte transversal. MATERIAL E METODO: Estudo comparativo, transversal, pareado. O teste vestibular foi realizado em duplicidade, com intervalo maximo de cinco dias entre um e outro exame. No primeiro teste, os pacientes foram orientados a nao ingerir cafe 24 horas antes do exame; no segundo teste, os pacientes foram orientados a beber cafe como de costume. Todos os participantes tinham indicacao clinica de se submeter ao teste vestibular e tinham o habito de tomar cafe. RESULTADOS: Participaram do estudo 19 mulheres com idade media de 49,5 anos. O consumo medio de cafe foi de tres xicaras por dia. As queixas de ansiedade e cefaleia foram associadas ao teste realizado com suspensao do cafe. Nao houve diferenca estatisticamente significante nos resultados dos exames realizados com e sem ingestao de cafe. CONCLUSAO: A ingestao moderada de cafe nao interferiu no resultado do teste vestibular. Considerando ser recomendavel que o paciente esteja tranquilo ao se submeter ao teste vestibular e que a meia-vida da cafeina e de apenas seis horas, sugerimos que a orientacao para a suspensao subita e completa da ingestao moderada de cafe antes do teste vestibular para os individuos habituados a ingestao diaria seja reavaliada.

Validade da prova calórica monotermal em comparação à estimulação bitermal

BACKGROUND the use of monothermal caloric testing as a screening tool for vestibular asymmetry has been considered as an alternative to bithermal caloric testing. AIM to evaluate the effectiveness of monothermal stimulation when compared to bithermal stimulation in the diagnosis of labyrinth asymmetry. METHOD the results of 389 vectoelectronystagmography, performed between 1998 and 2007, were analyzed. Monothermal stimulation at 30°C and 44°C with unilateral weakness (UW) cut-off at 20% and 25% was compared to bithermal stimulation with cut-off at 25% (gold standard). The analysis was aimed at finding which kind of monothermal caloric test (30°C or 44°C) and which kind of cut-off (20% or 25%) presented the highest specificity and sensitivity values in comparison with bithermal caloric testing. RESULTS sensitivity and specificity of monothermal caloric tests were: 84% and 80%, at 30°C with UW at 20%; 78% and 90%, at 30°C with UW at 25%; 81% and 78%, at 44°C with UW at 20%; 76% and 85%, at 44°C with UW at 25%. CONCLUSION monothermal caloric testing with 30°C stimulus presented the highest sensibility and specificity values in comparison to the results obtained with bithermal stimulation. However, no significant difference was observed between such values and those obtained with 44°C stimulus. In all of the analyses, monothermal testing presented low sensitivity. Thus, the abnormal result of bithermal caloric testing might be seen as normal in monothermal stimulation. The use of monothermal testing as a screening tool is better recommended for individuals whose medical history suggests a low probability of vestibular disease.

Evaluation of the caffeine effect in the vestibular test

UNLABELLED Exists controversy about the interference of the caffeine in the vestibular test. Coffee is the richest source of caffeine. While in some services, the patients were oriented to suspend the ingestion of caffeine 24 to 48 hours before the vestibular test, others did not consider the suspension of this drink necessary. AIM To evaluate the effect of caffeine in the vestibular test result. STUDY DESIGN Clinical with transversal cohort. MATERIAL AND METHOD Sectional and matched research. The vestibular test was performed twice in the same patient, with five days interval between the exams. In the first test, the patient did not drink coffee 24 hours before the exam; in the second, the patient drunk coffee as usual. All of the participants had clinical indication for vestibular test and were used to drinking coffee. RESULTS Nineteen women, medium age of 49.5 years, participated. The average coffee consumption was three cups per day. The complaints of anxiety and headache were associated with the submission to the vestibular test without coffee. The exams were not statistically different comparing the results of the tests performed with and without the coffee ingestion. CONCLUSION The moderate ingestion of coffee was not shown to interfere in the results of the vestibular test. Considering that it is recommended that the patient be calm to be submitted to the vestibular test and that the half-life of the caffeine is only six hours, we suggest that the orientation of complete and abrupt drinking coffee suspension of moderate dose before the vestibular test for the individuals used to daily drinking coffee be reevaluated.

Ocular Vestibular Evoked Myogenic Potentials

Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP) testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective To summarize recent developments in ocular VEMP testing. Results Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

Vestibular-Evoked Myogenic Potential (VEMP) in the Evaluation of Schistosomal Myeloradiculopathy

Schistosomal myeloradiculopathy (SMR) is the most severe and disabling form of schistosomiasis. The diagnosis is based on clinical, laboratory, and image data. Vestibular-evoked myogenic potential (VEMP) is a neurophysiologic test that assesses the vestibulospinal pathway through acoustic or galvanic stimuli. The aim of this study was to evaluate cervical spinal abnormalities in patients with SMR. Fifty-two subjects were evaluated, of whom 29 had SMR and 30 did not (normal control). Normal VEMP was observed in all volunteers without SMR. Abnormal VEMP was recorded in 34% of the group with SMR. After treatment, abnormal VEMP was found in 80% of those with persistent neurologic abnormalities. VEMP is a functional test, and the alteration may precede image abnormalities. This procedure may be useful for early diagnosis of schistosomal cervical spinal cord involvement.