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Unraveling reading comprehension in Chinese ADHD: insights from individual fixation-related potentials analysis
Poster Session C, Friday, October 25, 4:30 - 6:00 pm, Great Hall 3 and 4
Pei-Chun Chao1, Jou-An Chung1,2, Jie-Li Tsai3, Chia-Ying Lee1,2,3; 1Academia Sinica, Taiwan, 2National Central University, Taiwan, 3National Chengchi University, Taiwan
Successful reading comprehension requires multiple cognitive processes, such as retrieving a word's orthographic, phonological, and semantic information, maintaining and integrating it into working memory, constructing contextual information, and predicting subsequent words to promote comprehension. While people with Attention Deficit/Hyperactivity Disorder (ADD / ADHD) can decode words, their sustained attention deficits, limited working memory, and inhibition problems may hinder reading comprehension. However, existing evaluation methods heavily depend on subjective observation and standardized paper-and-pencil literacy tests, failing to identify the specific cognitive deficits underlying the reading comprehension difficulties in ADD/ADHD. This study simultaneously recorded eye movements and fixation-related potentials (EMFRPs) to objectively assess online reading comprehension in adults with ADD or ADHD. Previous research has used the effects of word frequency and predictability on N400s to evaluate the capacity for retrieving lexical information and contextual processing during reading comprehension. Therefore, we collected a normative EMERP database from forty-seven college students with normal reading ability, who read 2504 words across twenty-two articles in traditional Chinese. Each word's predictability was estimated using a cloze test with 32 readers, and its frequency was calculated as log-transformed occurrences per million from the Academia Sinica Corpus of Contemporary Taiwan Mandarin (ASCCTM). Linear mixed-effects models (LMMs) were applied to single-trial fixation-related potentials (FRPs). The word predictability effect and its interaction with frequency (WP*WF) occurred on N400s between 375-475ms in central-parietal regions. The reduction in N400 amplitude with increasing predictability was observed only for infrequent words, indicating that most adults can efficiently use contextual clues to comprehend unknown words. This study further assembled the EMFRP data in four adults with ADHD and another four with ADD. The ADHD group showed a significant WF effect but null WP and WP*WF effects in the frontal electrodes between 425-525 ms. Evidence suggests that although people with ADHD retain intact word decoding skills, they struggle to integrate contextual information for prediction. On the other hand, the ADD group demonstrated the delayed and frontal shifted WP effect and WP by WF interaction on N400, implying a more demanding reading comprehension process. These findings suggest differential cognitive deficits in vocabulary retrieval and contextual prediction for reading comprehension in ADHD and ADD. Additionally, these variations in WF, WP, and WP*WF effects on N400s can be estimated in individual EMFRP data. Through EMFRP profiles, we can uncover distinct reading processes and effectively evaluate the reading proficiency of people with ADD and ADHD.
Topic Areas: Reading, Disorders: Developmental