A Study Of Event-Related Potentials (ERPs) N₄₀₀ With Chinese Idioms And Sentences In Healthy Subjects And It S Clinical Application

[Objectives]:The processing of phonological, orthographical and semantic word attributes has been commonly explored with electrophysiological methods using simple contexts where competition with features is eliminated. N400 is a commonly used event-related electrophysiological marker of word discordance. However, the interaction between phonological, orthographical and semantic attributes has not been systematically examined in Chinese. We therefore recorded the latency, amplitudes and scalp distribution of N₄₀₀ with matching and mismatching ending characters or ending words in Chinese idioms and sentences, compared the differences between Chinese characters and Western spelling words. We then measured N₄₀₀ in cerebral infarction patient with/without aphasia and assessed the correlation between N₄₀₀ and patients' language function. [ Methods]:We recorded the N₄₀₀ in 15 volunteers who are 21-36 years old, right-handed to study the N₄₀₀ in Chinese idioms and sentences. 22 patients suffered from acute cerebral infarction with/without aphasia (Broca's aphasia and Wernicke's aphasia) andl5 age-education- right handed matched controls were tested using Chinese sentences as stimulus.Subject was asked to read the idioms or sentences displaying on ascreen word by word while the ERPs-N₄₀₀ potentials were recorded from the electrodes with the 10/20 systems. In idiom testing, the ending character was changed or unchanged with its orthography, semantic meaning andphonology such as . In sentencestesting, the ending or target word of a sentence would be changed or unchanged such as "I drink a cup of-milk.", "Bookstores sell weapons." [Results]:When tested N₄₀₀ with mismatching ending word or target character of sentences and idioms, N₄₀₀ amplitude was higher and the latency was delayed. On the contrary, the amplitude reduced and the latency advanced in the matching test in volunteers.In both groups of patients and the control subjects, the N₄₀₀ shows the similar trends as the results of the volunteers. Compared with the control group, the amplitudes in patients without aphasia were reduced in matching and mismatching tests. The N₄₀₀ latency of patients delayed in matching group except the Fz point while no significance was found in mismatching groups. In another test, the aphasia patient show reduced amplitudes and delayed latency compared with the control subject. Patients of right hemisphere lesion without aphasia showed normal N₄₀₀ [Conclusion]:Chinese idiom and sentence are the favorable stimulus for ERPs-N₄₀₀ test. By changing the ending word to match or to mismatch the idiom and sentence one can easily find N4oo of great value. With the different meaning of character and word more choice would be provided by Chinese for ERPs-N₄₀₀. It is also interesting in investigation of N₄₀₀ for clinical application to study the language function of the patients with cerebral blood vessel disease. Particularly, the cases with aphasia are different kinds.