# Neurofeedback Effects on EEG Connectivity among Children with Reading Disorders: I. Coherence
###### Abstract  
Electroencephalograms (EEGs) of children with reading disorders (RDs) are characterized by a higher theta and a lower alpha than those of typically developing children. Neurofeedback (NFB) may be helpful for treating learning disorders by reinforcing a reduction in the theta/alpha ratio. Several studies have suggested that NFB may lead to EEG power normalization and cognitive improvements. To further explore brain changes in isolated areas, the aim of this study was to explore the effects of an NFB protocol on functional connectivity (coherence) among children with RDs. Twenty children with an RD and an abnormally high theta/alpha ratio underwent 30 NFB sessions, and five children with the same characteristics received a sham NFB treatment. On average, the children in the NFB group showed an increase in reading accuracy and comprehension scores; their coherence diminished in the delta, theta, and beta bands and increased in the alpha band, primarily the theta intrahemispheric coherences of the left hemisphere, which is closely associated with reading. In contrast, children who received the sham NFB treatment did not show reading changes and had few changes in their coherence patterns. These preliminary results suggest that NFB can positively impact reading-related functions in the brain networks of children with RDs. EEG; qEEG; connectivity; coherence; neurofeedback; reading disorder; learning disorder; dyslexia +
Footnote †: journal: Medical  
reading disorders, abnormalities in cortical connectivity have been found. These could be due to alterations in neuronal migration [8], as reported by [PERSON] et al. [9], who found evidence of cortical anomalies in the brains of people with dyslexia in postmortem studies, including neuronal ectopias and dysplasias located predominantly in the left perisylvian regions. Using imaging techniques such as magnetic resonance imaging, structural differences between dyslexic patients and individuals with typical development have been found. Dyslexic adult patients have reduced brain volume and abnormal lateralization, and their white matter depth is greater than normal [10]. Among children with dyslexia, decreased cortical thickness has been reported not only in regions associated with reading (occipitotemporal and occipitoparietal areas of both hemispheres) but also in other brain areas, including the right orbitofrontal cortex and left anterior cingulate cortex [11]. Regarding gyrification, [PERSON] et al. [10] reported lower gyrification in dyslexic adults, while [PERSON] et al. [11] reported higher gyrification in dyslexic children. The increase in gyrification serves to improve communication between neighboring areas; however, it comes at the cost of reducing effective long-range connectivity. A cortical network in the left hemisphere involves three specialized regions that participate in reading: (1) the left dorsal temporoporarietal circuit located around the area of Wernicke, including the extrastriate cortex, fusiform gyrus, and inferior temporal region, which specializes in phonological decoding; (2) the left ventral occipitotemporal circuit that houses the visual area of word form, to which visual and orthographic recognition based on memory is attributed; and (3) the left inferior frontal circuit, classically called Broca's area, which is involved in the articulation of words [12]. It has been proposed that people with dyslexia exhibit dysfunction in this reading network, consisting of underactivation of the left temporoporarietal region, involving the inferior parietal region, temporal lobe, and fusiform gyrus; underactivation of the left inferior frontal gyrus; and overactivation in the left primary motor cortex and in the anterior insula [13]. Among children with dyslexia, unlike adults with dyslexia, underactivation in the temporoporarietal region has not been confirmed, and occipitotemporal underactivation is less extended than in adults [14].