Cervical Vestibular-Evoked Myogenic Potentials in Sedated Toddlers

Abstract Introduction Cervical vestibular-evoked myogenic potentials (cVEMPs) are difficult to test in toddlers who cannot follow instructions or stay calm. Objective Due to the growing need for vestibular testing in very young children as a part of a delayed walking assessment battery, this study aimed to provide a solution to this problem by recording the cVEMPs in toddlers during sedation. Method The cVEMPs measures were assessed in 30 toddlers aged 12 to 36 months with normal motormilestones. They were sedated with chloral hydrate. Then, the head was retracted ~ 30° backward with a pillow under the shoulders, and turned 45° contralateral to the side of stimulation to put the sternocleidomastoid (SCM)muscle in a state of tension. Results The P13 and N23 waves of the cVEMPs were recordable in all sedated toddlers. The cVEMPs measures resulted in the following: P13 latency of 17.5 ± 1.41 milliseconds, N23 latency of 25.58 ± 2.02 milliseconds, and peak-topeak amplitude of 15.39 ± 3.45 μV. One-sample t-test revealed statistically significant longer latencies and smaller amplitude of the toddlers' cVEMPs relative to the normative data for adults. Conclusions The difficulty of cVEMPs testing in toddlers can be overcome by sedating them and attaining a position that contracts the SCM muscle. However, the toddlers' recordings revealed delayed latencies and smaller amplitudes than those of adults.

Potencial evocado miogênico vestibular ocular e cervical simultâneo em indivíduos normais / Ocular and cervical vestibular evoked myogenic potential simultaneous in normal individuals

RESUMO Objetivo: Caracterizar o registro e analisar os resultados do potencial evocado miogênico vestibular cervical e ocular combinado em indivíduos sem queixas auditivas e vestibulares. Métodos: Participaram da pesquisa 30 indivíduos sem queixa auditiva e com audição dentro dos padrões de normalidade. A coleta de dados foi realizada por meio do potencial evocado miogênico vestibular cervical e ocular registrados simultaneamente. Resultados: Houve diferença entre as orelhas direita e esquerda para a amplitude das ondas P13 e N23 do potencial evocado miogênico vestibular cervical e para a latência da onda N10 do potencial evocado miogênico vestibular ocular. No gênero feminino não houve diferença entre as orelhas direita e esquerda para a amplitude das ondas P13, N23, N10, P15, interamplitude no potencial evocado miogênico vestibular cervical e interamplitude no potencial evocado miogênico vestibular ocular e para a latência das ondas P13, N23, N10 e P15. No gênero masculino houve diferença entre as orelhas direita e esquerda para a amplitude da onda P13. Conclusão: Os resultados do potencial evocado miogênico vestibular cervical e ocular combinado foram consistentes, uma vez que as respostas geradas pelos potenciais evocados miogênicos vestibulares apresentaram morfologia, latência e amplitude adequadas, o que permite a avaliação da via vestibular ipsilateral descendente e da via vestibular contralateral ascendente.

ABSTRACT Purpose: To characterize the recording and analyze the results of the combined cervical and ocular vestibular evoked myogenic potential in individuals without hearing and vestibular complaints. Methods: In this study, 30 individuals without hearing complaints and hearing within normal limits were evaluated. Data were collected through the simultaneous recording of cervical and ocular vestibular evoked myogenic potential. Results: Differences were observed between the right and left ears for the amplitude of waves P13 and N23 of the cervical vestibular evoked myogenic potential and the latency of wave N10 of the ocular vestibular evoked myogenic potential. For female subjects, there was no difference between the right and left ears for the amplitude of waves P13, N23, N10, and P15; interamplitude in cervical vestibular evoked myogenic potential and interamplitude in ocular vestibular evoked myogenic potential; and latency in waves P13, N23, N10, and P15. For male subjects, there was a difference between the right and left ears for the amplitude of wave P13. Conclusion: The results of the combined cervical and ocular vestibular evoked myogenic potentials were consistent, because the responses generated by the vestibular evoked myogenic potentials presented an adequate morphology, latency, and amplitude, allowing for the evaluation of the ipsilateral descending vestibular pathways and the contralateral ascending vestibular pathways.

Avaliação dos potenciais evocados cocleares após lesão do utrículo por eletrocauterização / Assessing cochlear evoked potentials after electrocautery-induced trauma to the utricle

A utriculostomia é uma nova alternativa cirúrgica para a doença de Ménière. A hipótese cirúrgica desse procedimento é a de que o desfecho de uma lesão do utrículo por eletrocauterização não interfere na função coclear. Contudo, a hipótese de que essa abordagem do utrículo preserva a audição ainda não foi comprovada. OBJETIVO: Determinar se ocorrem mudanças nos potenciais elétricos evocados na cóclea e no nervo auditivo antes, durante e 1 mês após o procedimento cirúrgico no utrículo em modelo animal. MATERIAIS E MÉTODOS: Estudo experimental: Oito ovelhas foram submetidas à lesão do utrículo por eletrocauterização e sua função coclear foi avaliada por meio de eletrococleografia, registrando-se os potenciais elétricos evocados nos períodos pré-operatório, pós-operatório imediato e pós-operatório de médio prazo. Os resultados foram analisados estatisticamente. RESULTADOS: Não houve variação estatisticamente significativa na amplitude (p = 0,099) e na latência (p = 0,591) antes e 1 mês após o procedimento cirúrgico. Houve alteração estatisticamente significativa na razão entre potencial de somação/potencial de ação (p = 0,0122), representando uma perda calculada de 11,8 dB. CONCLUSÃO: A intervenção realizada no utrículo neste estudo permite concluir que, tendo em conta respostas eletrofisiológicas deficientes observadas durante e 1 mês após o procedimento cirúrgico, houve preservação da audição nas ovelhas operadas.

Utriculostomy is a new surgical alternative for Ménière's disease. The basis of this procedure is that the outcome of an electrocautery-induced utricular trauma does not affect cochlear function. However, a demonstration of the hypothesis that this approach to the utricle would preserve hearing is still pending. OBJECTIVE: To determine whether any changes would occur in the electrical potentials evoked in the cochlea and auditory nerve before, during, and 1 month after a surgical procedure in the utricule in an animal model. MATERIALS AND METHODS: An experimental study. Eight sheep underwent electrocautery-induced utricular trauma, and their cochlear function was assessed by electrocochleography - recording of electrical evoked potentials, in the preoperative, immediate postoperative and medium-term postoperative periods. The results were analyzed statistically. RESULTS: There were no statistically significant variations in amplitude (p = 0.099) and latency (p = 0.591) before and 1 month after the surgical procedure. There was a statistically significant change in the summation of the potential/action potential area ratio (p = 0.0122), a calculated loss of 11.8 dB. CONCLUSION: The intervention performed in this study enabled us to conclude that, taking into account the impaired electrophysiological responses observed during and 1 month after the surgical procedure, hearing was preserved in the operated sheep.