Abstract
BackgroundWhile there are studies on visual lexical processing in other languages among dyslexics, no studies were done in the Malay language. The origin of visual lexical processing might be different in the Malay language. We aimed to detect the source localisation of visual mismatch negativity (vMMN) during Malay orthographic lexicon stimulations, employing an event-related potential (ERP) study.MethodsTwelve dyslexic and twelve non-dyslexic children participated in this study. They pushed button ‘1’ when they saw real (meaningful) Malay words and button ‘2’ for pseudowords (meaningless). The source localisation of vMMN was performed in the grand average waveform by applying the standardised low-resolution brain electromagnetic tomography (sLORETA) method using Net Station software.ResultsLeft occipital (BA17) and left temporal (BA37) lobes were activated during real words in the non-dyslexic and dyslexic children, respectively. During pseudowords, BA18 and BA17 areas of the left occipital lobe were activated in the non-dyslexic and dyslexic children, separately. vMMN sources were found at the left temporal (BA37) and right frontal (BA11) lobes in non-dyslexic and dyslexic children, respectively.ConclusionRight frontal lobe is the decision-making area where vMMN source was found in dyslexic children. We concluded that dyslexic children required the decision-making area to detect Malay real and pseudowords.
Highlights
Reading is an ability that is mastered automatically by skilled readers, but in certain reading disabilities such as dyslexia, the readers exhibit poor mastery of reading skills, which can be due to reduced neural activation to word-like stimuli in certain regions of reading neural networks
Non-dyslexic group evoked source activation at BA17 and dyslexic group activated at BA37 which were in the left occipital lobe and left temporal lobe, respectively
During pseudoword stimulation both groups activated in nearly the same areas: non-dyslexic group activated in BA18 and dyslexic group evoked at BA17 and both Brodmann areas are located in the left occipital lobe (Table 1, Figure 1)
Summary
Reading is an ability that is mastered automatically by skilled readers, but in certain reading disabilities such as dyslexia, the readers exhibit poor mastery of reading skills, which can be due to reduced neural activation to word-like stimuli in certain regions of reading neural networks. According to Richlan [3], functional brain abnormalities in dyslexics were poorly activated in the left hemisphere-reading network in the occipito-temporal, inferior frontal and inferior frontal regions, which may be the cause for the poor automatic word recognition of the orthographic lexicon. An eventrelated potential (ERP) is an electrophysiological technique that can provide objective spatial source localisation for automatical recognition and this is reflected in the mismatch negativity (MMN) component. Because MMN elicitation can be evoked by visual orthographic lexicon stimulations, it is worthwhile to know where the neural sources generate the automatic recognition of orthographical lexicons among dyslexics during the reading process, allowing the exploration of possible source abnormalities in dyslexics compared to that in normal readers. We aimed to detect the source localisation of visual mismatch negativity (vMMN) during Malay orthographic lexicon stimulations, employing an event-related potential (ERP) study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
