Development of a Stimulator for Elicitation of Auditory Evoked Potentials by Japanese Words.

本文介绍了一种用日语单词进行听觉诱发电位测试的听觉刺激器。这个刺激器随机产生两个不同频率的短纯音和两个不同的单词。选择了几对第一个发音相同而另一个发音不同的日语单词作为刺激。最后选出了以下6对：“A-ka，A-o”;“A-shi，A-me”;“I-nu，I-su”;“Ku-ma，Ku-tsu”;“Ha-na，Ha-to”和“Sa-ru，Sa-ra”。那些以元音作为第一个音的声音被清楚地区分开，然而，那些以辅音，特别是摩擦音作为第一个音的声音，如“Sa-ru; Sa-ra”被模糊地区分开。这可能是由于机器的模数转换对摩擦音不太敏感。对于P300的激发，一个短纯音在20%时给出，另一个在80%时给出。以低频短纯音作为靶刺激。声音刺激也给予20和80%的每个字。P300来源于与耳垂相连的顶点，对日语中的“A-ka，意思是红色”和“A-o，意思是蓝色”这两个词进行语音刺激，以及短纯音刺激，都能诱发P300。4岁男童短纯音不能诱发P300，而声刺激能诱发P300。实验证明，即使是短纯音不能诱发P300的儿童，该装置也能有效地诱发P300。声刺激P300潜伏期较短纯音刺激P300潜伏期长。这种差异可能与第二声辨别两个词的反应时间延迟有关，按下按钮任务的反应时间也是词辨别比声调辨别延迟。

An auditory stimulater using Japanese words for auditory evoked potentials was developed. This stimulator generates two tone bursts of different frequencies, and two different words at random. Several pairs of Japanese words whose first sound was the same and the other was different were chosen for the stimulation. Finally the following 6 pairs were selected: "A-ka, A-o"; "A-shi, A-me"; "I-nu, I-su"; "Ku-ma, Ku-tsu"; "Ha-na, Ha-to" and "Sa-ru, Sa-ra". those which had a vowel as the first sound were clearly differentiated, however, those which had a consonant, especially fricative sound as the first sound such as "Sa-ru; Sa-ra" were equivocally differentiated. It is likely due to the analog to digital conversion of the machine was less sensitive to the fricative sound.For the elicitation of P300, one tone burst was given at 20% and the other was given at 80%. The tone burst which was given at low frequency was used as the target stimulation. The sound stimulation was also given at 20 and 80% for each word. P300 was derived form the vertex referred to the linked ear lobes.The P300 could be elicited by this sound stimulation of paired Japanese words of "A-ka which means red" and "A-o which means blue" as well as by the tone burst stimulation. In a 4-year-old boy, the tone bursts could not elicit P300, but the sound stimulation could. It is proved that this equipment is useful for elicitation of P300 even in children whose P300 cannot be evoked by tone burst. The latency of P300 was longer by sound stimulation than by tone burst. This difference probably relate to time delay of discrimination of the two words by the second sound.The response time evaluated by button press task was also delayed for the word discrimination than for the tone discrimination.