Kujala T, Lovio R, Lepistö T, Laasonen M, Näätänen R
Helsinki Collegium for Advanced Studies, University of Helsinki, Helsinki, Finland.
Clin Neurophysiol. 2006 Apr;117(4):885-93. doi: 10.1016/j.clinph.2006.01.002. Epub 2006 Feb 23.
Dyslexia is associated with impairments in the phonological system or with more general auditory dysfunctions. We determined the discrimination of 5 sound contrasts (pitch, duration, intensity, location, and the presence of a gap) in dyslexia with the mismatch negativity (MMN).
We compared MMNs of 9 adult dyslexic and 11 control subjects with a new 5-deviant paradigm which enables one to assess the discrimination of each of these features in 15 min. Also, a control oddball condition with pitch and duration deviants was included. In the new paradigm, all deviant stimuli are presented in the same stimulus block so that the standard stimuli, of which there are 50%, alternate with the deviant stimuli.
In the 5-deviant paradigm, a diminished pitch-MMN and an enhanced location-MMN were found in dyslexic individuals. Furthermore, pitch and duration MMNs in this and in the oddball paradigms suggested that smaller MMNs are elicited in the new than oddball paradigm in dyslexic subjects.
Pitch discrimination is impaired in dyslexia. However, location discrimination, not addressed previously with MMN, is enhanced. Furthermore, dyslexic subjects are more impaired in detecting changes in sound streams with than without variation.
In dyslexia research, the new 5-deviant MMN paradigm is feasible and even more sensitive than the traditional oddball paradigm.
阅读障碍与语音系统受损或更普遍的听觉功能障碍有关。我们用失匹配负波（MMN）来测定阅读障碍者对5种声音对比（音高、时长、强度、位置和有无间隙）的辨别能力。
我们采用一种新的5偏差范式，比较了9名成年阅读障碍者和11名对照者的MMN，该范式能让人在15分钟内评估对每种特征的辨别能力。此外，还纳入了一个音高和时长偏差的对照奇偶数范式。在新范式中，所有偏差刺激都在同一个刺激块中呈现，这样50%的标准刺激与偏差刺激交替出现。
在5偏差范式中，阅读障碍者的音高MMN降低，位置MMN增强。此外，在这个范式和奇偶数范式中的音高和时长MMN表明，阅读障碍者在新范式中比在奇偶数范式中诱发的MMN更小。
阅读障碍者的音高辨别能力受损。然而，之前未用MMN研究过的位置辨别能力增强。此外，阅读障碍者在检测有变化而非无变化的声音流变化时受损更严重。
在阅读障碍研究中，新的5偏差MMN范式是可行的，甚至比传统的奇偶数范式更敏感。
