Constructing New Neurophysiological Indicators of Executive Attention Function in Children with Attention Deficit Hyperactivity Disorder

Abstract

Background and aims: Deficit of executive attention function(EAF) is a neuropsychological /neurobehavioral problem in children with attention deficit hyperactivity disorder (ADHD) There are several researches claimed ADHD children have both neuropsychological/neurobehavioral and neuroimagical function impairments as in endophenotypes level But seldom studies examined the relationship between neurophysiological and neuropsychological/neurobehavioral functions As Franke et al (2009) mentioned level concept in endophenotypes more attention was paid on the relation of neurophysiological indicators and neuropsychological/neurobehavioral functions in ADHD and to discuss the level of neuropsychopathology mechanism The dissertation comprises two original studies from this context and construct neurophysiological indicators to find relation with EAFs help screening attention problems and hope to be indicators of neuropsychotherapy We studied ADHD children’s electroencephalography(EEG) and event-related potential(ERP) techniques separately First of all although signal artifacts occur often in children but an electroencephalogram valid rate (EEGVR) constructed by excluding the artifacts might be meaningful to evaluate children’s neuropsychological functions So the aim of first study was to develop an easy screening index the EEGVR and to investigate EAFs in children using this index In the second study the ERP technique were examined while we want to investigated whether in ADHD children who made impulsive error (IE) would have less error-related negativity (ERN) And if they had less ERN would correlate with poorer EAFs Methods: In study 1 the EEG was carried out during a 4-min simple reaction time (SRT) task as standard procedure consisting of 26 with attention-deficit–hyperactivity disorder (ADHD; mean age 9 8 years; range 8–11 3 years) and 24 without (mean age 10 1 years; range 7 8–12 years) An easy index was derived from the EEGVR using area under the receiver operating characteristic curve The index was applied to regroup the 50 children into high valid rate (HVR) and low valid rate (LVR) groups while the Comprehensive Non-verbal Attention Test battery(CNAT) and four behavioral questionnaires were compared between the HVR and LVR groups in order to investigate the validity of this index In study 2 49 with ADHD and 41 without ADHD) were investigated by a 4-minute SRT task and simultaneous EEG When they made IE the ERN was defined as error-awareness The average area under curve of ERN in the control group with IEs was used as the proper criterion for regrouping the ADHD children into two groups: ADHD children with enough ERN (ADHD-enough ERN) and those with less ERN (ADHD-less ERN) EAFs from CNAT were used as objective indices and behavioral questionnaires were used as subjective indices and statistically analyzed within ADHD groups Results: Study 1 showed the EEGVR at 75% was optimal to identify HVR and LVR with sensitivity 0 769 and specificity 0 792 The LVR group had significantly lower scores on both CNAT and the behavioral questionnaires although the demographic variables and full-scale intelligence quotient (FSIQ) were similar between the two groups The EEGVR in a SRT task might be an easy and effective index to screen the EAFs of children and could consequently contribute to the diagnosis of ADHD Study 2 showed forty-eight percent of the children made IEs in SRT ADHD (n=31 63%) was significantly more than in the control group (n=12 29%; P<001) The ADHD group had significant less ERN than did the control group while making IE especially at frontal and central sites (P<01) Both ADHD-less ERN and ADHD-enough ERN groups had poorer subjective EAFs on questionnaires Only the ADHD-less ERN group had significant poorer objective EAFs on the CNAT than did the ADHD without IE ADHD children had less amplitude especially in frontal and central ERN of IE And the ERN of IE in ADHD children might help to differentiate subtypes of ADHD with different neuropsychological abilities and the possibility that ADHD-less ERN children might be confirmed a meaningful subgroup that needs close follow-up treatments different from standard or both Discussions and Conclusions: The finding of EEGVR supplies with neurobehavioral evidence that ADHD children have both processing speed and lack of inhibition control when the detecting movements is not only goal of task demand The ERN of IE in SRT presents the fails of inhibition control and motivational factors which relevant with EAFs also their unstable motivational and reward-related processes are implicated different subtypes of ADHD We have developed two neurophysiological indicators both only using a 4-minutes SRT during simultaneously EEG recording as predictors of children’s executive attention functions including EEGVR and ERN of IE in SRT even can screen if they had ADHD problems Future studies should construct norms of these indicators and integrate with interdisciplinary research to develop indexes of endophenotype level and examinate the clinical efficacy and validity of them

Date of Award	2017 Dec 20
Original language	English
Supervisor	Nai-Wen Guo (Supervisor)