An Event-Related Potentials Study For Chinese Characters Cognition In Attention Deficit Hyperactivity Disorder Children

Objective To investigate the dysfunction and neural mechanism of Chinese character priming effect in attention deficit hyperactivity disorder (ADHD) children. Recognition potentials under Chinese character semantic priming task were recorded in ADHD children by comparing with normal control.,at the same time, To investigate the improvement of the brain function and the effect of Chinese character cognitive after EEG biofeedback therapy in attention deficit hyperactivity disorder (ADHD) children by analying the feature of ERP between pre and after EEG biofeedback therapy evoked by Chinese characters.Methods Fifty-two ADHD children (mean age: 9.51±1.71years) and forty-five age- matched control children without ADHD (mean age: 10.09±1.70years) were asked to perform a Chinese character semantic priming task while electroencephalogram were recorded. Subjects were instructed to judge whether the presented target word was a related word ,unrelated word or a pseudoword. Event-related potentials (ERPs ) were elicited by the Chinese character semantic priming task which contains related (eg.cox and horse), unrelated (eg.rain and hand), pseudowords stimuli and averaged with brain electricity source analysis (BESA) software. Twenty-one ADHD children (mean age: 9.48±1.52years) were under EEG biofeedback therapy .The IVA-CPT and recognition potentials under Chinese character semantic priming task were recorded pre and after EEG biofeedback therapy. Event-related potentials (ERPs ) were elicited by the Chinese character semantic priming task which contains related (eg.cox and horse), unrelated (eg.rain and hand), pseudowords stimuli and averaged with brain electricity source analysis (BESA) software.Result Part 1:①behavioral result: Reaction time of character unrelated stimuli in ADHD children (1251.80±255.54ms) is longer than normal control (1130.81±194.17ms) (P<0.05);②ERPs waveforms and componets are coincident for all lead sufaces including N1,P2,N2,P3;③ERP-N2: Amplitude of character related N2 at Cz lead in ADHD children {-7.7(-12.8,-5.0)μv} was larger than that of normal control{-5.6(-9.4,-3.2)μv}(P<0.05).④ERP-P3: Amplitude of character unrelated stimuli P3 at Cz lead in ADHD children{5.4(2.0,9.5)μv} was significantly lower than that of normal control {9.5(4.2,16.9)μv} and there was significantly statistical meaning(P<0.01).Part 2:①ERPs waveforms and componets are coincident for pre and after therapy, including N1,P2,N2,P3;②IVA-CPT result: The visual attention quotient and the general attention quotient in ADHD children is increased after treatment(P<0.05).③ERP-N2: Amplitude of character related N2 at Cz lead(-3.95±5.63μv)was more decreased than pre therapy (-10.14±8.27μv)(P<0.05).④ERP-P3: Latent of character unrelated stimuli P3 at Cz lead(619.24±63.64ms) was significantly shorter than that of pre therapy (660.76±67.88ms)(P<0.01).Conclusion There is a positive correlation between the amplitude of N2 and the difficulty of the character semantic priming.It is more difficult for ADHD than normal control to complish the same semantic task.ADHD children need adopt more attention resources than normal control,and our result amplitude of character related-N2 and unrelated-P3 may become a marker to measure the development of recognition of ADHD children in semantic processing and be good helpful to the diagnosis of ADHD. Performance of the Chinese character coginitive is effected by the core symptoms of ADHD.There is a positive correlation between the amplitude of N2 and the difficulty of the character semantic priming.The EEG biofeedback therapy is helpful to improvement of the attention in ADHD,therefore it is beneficial to increase the level of character coginitive.