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Arquivos de Neuro-Psiquiatria

Print version ISSN 0004-282X

Arq. Neuro-Psiquiatr. vol.52 no.2 São Paulo June 1994

http://dx.doi.org/10.1590/S0004-282X1994000200009 

Dichotic words listening test: technical aspects and results in normal right-handed individuals

 

Teste de audição de palavras dicóticas: aspectos técnicos e resultados em pessoas destras normais

 

 

Ana Regina Caner-Cukiert; Arthur Cukiert

Deparment of Neurology and Neurosurgery, University of São Paulo School of Medicine, São Paulo, Brazil

 

 


SUMMARY

Dichotic listening tests have been being used in an increasing frequency to determine in a non-invasive way the cerebral dominance in right- and left-handed patients. This is especially relevant when surgery in eloquent brain areas is being contemplated. A Portuguese version of the dichotic words listening test was developed based mainly on Wexler's protocol. It consisted of 15 pairs of words with a stimulus dominance lower than 50%. They were recorded using natural voice and time and intensity synchronization by means of a specialized software. Each pair of words was presented twice in different channels within each block. The items were randomized and presented with a 300 msec interval between each trial. Four blocks of 30 pairs of words each were created, totalizing 120 trials. In the scoring process, the words heard over the right and left ears were wrote down. The number of times each word was heard over each ear was computed and their values subtracted yielding a partial score for each specific word pair. This process was repeated for all stimuli pair and a final score for right and left predominance was then reached. Thirty-two right handed normal individuals underwent the test 93.8% showed a right ear advantage. These results are very similar to the actual left hemisphere dominance rate in a right-handed population.

Key words: epilepsy, sodium amytal, dichotic listening tests, cerebral dominance.


RESUMO

Testes de audição dicótica vêm sendo cada vez mais empregados na determinação da dominância hemisférica para linguagem sem a utilização de métodos invasivos em pacientes destros e canhotos. Isto é especialmente importante quando cirurgias em áreas eloquentes do cérebro estão sendo planejadas. Uma versão em português deste teste foi criada baseada principalmente no protocolo de Wexler. Ele consistiu de 15 pares de palavras com uma dominância de estímulo menor que 50%. Estas palavras foram gravadas com voz natural e com sincronização de inicio de apresentação e intensidade por meio da utilização de programa de computador especializado. Cada par de palavras era apresentado duas vezes em diferentes canais em cada bloco. Os itens foram randomizados e apresentados com um intervalo de 300 msec entre cada amostragem. Quatro blocos de 30 pares cada foram criados, totalizando 120 amostragens. Na quantificação do teste, as palavras ouvidas nos ouvidos esquerdo e direito eram computadas. Em cada par, os valores obtidos à esquerda e à direita eram subtraídos, dando origem a um resultado parcial para cada par de estímulos. Este processo era repetido para todos os estímulos e um resultado final de predominância esquerda/direita era alcançado. Trinta e dois indivíduos normais foram submetidos a este teste. Trinta deles mostraram superioridade de ouvido direito. Estes achados são bastante próximos do valor real da dominância hemisférica esquerda em uma população destra.

Palavras-chave: epilepsia, amital sódico, teste de audição dicótica, dominância cerebral.


 

 

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

 

 

Acknowledgments - We would like to thank Dr. Zatorre (Montreal Neurologic Institute) for allowing the use of all his Lab facilities and specialized software that made it possible to prepare this Portuguese version of the dichotic listening test.

 

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Aceite: 5-outubro-1993.

 

 

Dr. Arthur Cukiert - Rua Baltazar da Veiga 367 apto 151 - 04510-001 São Paulo SP - Brasil.