No abstract

We neuropsychologically assessed cognitive deficits in 109 children with symptoms of attention-deficit/hyperactivity disorder (ADHD) and 51 children with typical development aged 7-8 years and 9-10 years and visually analyzed resting-state electroencephalography (EEG). The EEG recordings of children with ADHD more frequently contained EEG patterns of frontothalamic non-optimal functioning compared with controls, reflected by groups of bilaterally synchronous frontal theta waves (FTWs) and right hemisphere local deviations of brain electrical activity. We found cognitive impairments associated with ADHD in children with different deviations of resting-state EEG. Children with FTWs in both age groups exhibited pronounced difficulties in programming, regulation and control (executive functions), and verbal performance. Children with right hemisphere local EEG abnormalities had executive dysfunction combined with difficulties in nonverbal performance. Executive performance in typically developing children significantly improved from 7-8 to 9-10 years of age. An analysis of neuropsychological scores in children with ADHD symptoms from age 7-8 to 9-10 with the same EEG abnormalities indicated specific age-related improvement of cognitive abilities. In children whose EEG showed patterns of fronto-thalamic involvement presented significant improvement in executive and verbal performance from 7-8 to 9-10 years of age. Overcoming the same age gap in children with right hemisphere local EEG deviations significantly improved only nonverbal performance, whereas improvements in executive function were not statistically significant.

No abstract

We analyzed EEG recorded in the rest condition (eye closed) in 22 children aged from 7 to 8 years old who experienced learning difficulties and whose EEG recordings were characterized by sporadic short term appearance of bilateral synchronous slow waves over the frontal and/or frontal and central corticesfrontal theta waves (FTW). The vector autoregressive modeling was used in order to assess the strength of directed cortico cortical functional connectivity pattern for FTW and for surrounding EEG. The comparison of the two patterns showed that FTW is characterized by diffuse strengthening of the functional links connect ing frontal, central and (to some extent) temporal cortices as well as the links directed to the above regions from the other cortical areas. The results of the study suggest that FTW is most probably caused by the com mon for the frontal and central cortices neuronal theta activity synchronized via cortico subcortical links. This suggestion is in a good agreement with the view that FTW reflects the alterations in functioning of fronto thalamic system.Keywords: human EEG, frontal theta waves, fronto thalamic system, cortico cortical functional connectiv ity, vector autoregressive model, 7 8 year old children.

No abstract