Auditory evaluation of the microcephalic children with brain stem evoked response audiometry (BERA).

Microcephaly implies a reduced occipito-frontal circumference (< 2 Standard Deviation of normal) and therefore a small brain size, which is usually associated with different neurodeficit. Intactness of the auditory pathway in microcephalic as well as normal children was assessed by Brain stem Evoked Response Audiometry (BERA) to locate the exact site of lesion resulting in the auditory impairment, so that appropriate early rehabilitative measures can be taken. The study revealed that absolute peak latency of wave V, inter peak latencies of III–V and I–V were significantly higher (P- value <0.05 in each case) in microcephalics than the normal children. Auditory impairment in microcephaly is a common neurodeficit that can be authentically assessed by BERA. The hearing impairment in microcephalics is mostly due to insufficiency of central components of auditory pathway at the level of brainstem, function of peripheral structures being almost within normal limit.

Respostas auditivas evocadas de latência média em doenças neurológicas / Middle-latency auditory responses in neurological diseases

A presença das respostas auditivas evocadas de latência média permite-nos a avaliação da integridade do sistema auditivo periférico e central, incluindo os núcleos e vias auditivas existentes até ao nível da região subcortical. Desta forma, elas têm sido usadas para o estudo das alterações ocorridas em diferentes doenças neurológicas. OBJETIVOS: Verificar os valores dos períodos de latências destas respostas e detectar a presença das deflexões. CASUíSTICA E MÉTODO: Foram avaliados 20 pacientes portadores de doenças neurológicas existentes ao nível central, de diferentes etiologias, sendo analisadas as várias deflexões, positivas e negativas, geradas pelos potenciais auditivos evocados de latência média. Os sujeitos da pesquisa foram escolhidos por conveniência e os dados coletados foram avaliados levando-se em consideração a relação interindivíduos. FORMA DE ESTUDO: Foi adotado o estudo de Coorte, com avaliação contemporânea. RESULTADOS: Foram analisados estatisticamente e mostram alterações significativas da respostas evocadas de latência média em pacientes neurológicos. CONCLUSÃO: Nesses pacientes ou havia supressão das deflexões estudadas ou suas latências estavam aumentadas, quando comparadas com os padrões normais.

The presence of middle-latency evoked auditory potentials allows for integrity evaluation of both peripheral and the central auditory systems, and also, that of the nucleus and auditory pathways of sub-cortical region. They have also been used to study alterations of these structures in different neurological diseases. AIMS: the aim of this study is to verify the latency of the middle-latency evoked auditory potentials and detect the presence of any deflections in subjects with neurological diseases. MATERIALS AND METHODS: In a clinical and prospective trial, 20 patients having central neurological diseases of various etiologies were evaluated and, positive and negative deflections produced by the middle-latency evoked auditory potentials in these patients were analyzed. RESULTS: Data was statistically analyzed and showed significant modifications in middle-latency evoked auditory potentials. CONCLUSION: The authors concluded that patients with neurological disorders have either wave suppression or enlarged latency periods in relation to normal subjects.