# Neurofeedback Effects on EEG Connectivity among Children with Reading Disorders: I. Coherence
## 4 Discussion
### NFB Effects on Coherence in Children with RDs
This coherence maturation can be associated with improved reading comprehension and accuracy scores on the ENI-2 neuropsychological test. When comparing the changes that occurred in the NFB group with those that occurred in the Sham group, the changes in the NFB group are magnified, since in the Sham group, only an increase in beta coherence between T5 and T6 and a decrease in theta coherencebetween F7 and F8 leads were observed, without evidence of behavioral changes in reading. Although there are few reports on the placebo effect on EEG, some changes in EEG after placebo administration have been reported [64; 98]. To our knowledge, there are few other NFB studies in children with RDs. The first report of NFB in dyslexia was conducted by [PERSON] et al. [48], who described 12 clinical cases that had significant cognitive improvement after receiving a considerable number of NFB sessions of a personalized combination of various different protocols; these rarely included increases in alpha power. [PERSON] et al. [47] reported the first randomized controlled NFB study in dyslexia that included 19 dyslexic children; 10 of them received a personalized NFB protocol (different between subjects), and the remaining 9 constituted the control group; the main changes observed in the EEG recording at rest with eyes open of the treated children were an increased theta and lower alpha power and increased delta and alpha coherence; although improvement in spelling was observed, no changes were found in reading. More recently, [PERSON] et al. [43] reported a significant improvement in the reading skills and phonological awareness of six children who received twenty NFB sessions set to reduce delta and theta and increase beta in F7 and T3. Interestingly, the EEG analysis did not show noticeable changes in the power of the trained bands; however, they observed normalization of theta interhemispheric coherence between temporal areas, normalization of the delta band between anterior regions of the midline, and normalization of the beta band between the vertex and other areas. It was difficult to compare the results obtained with those of other studies. In this study, a theta/alpha ratio protocol was used while the subject had their eyes closed. The most similar approach in other research has been theta AP reduction, but the alpha power increase was rarely trained. Two main factors explain the difficulties in comparing the results of neurofeedback: (1) EEG rhythms have different cerebral origins, and therefore, the reinforcement of particular frequencies will activate different brain networks; and (2) the eyes-open and eyes-closed conditions are related to different patterns of EEG frequencies recorded at the scalp. Eyes being closed produces an enhancement of the alpha rhythm, while eyes being open generates visual stimulation and activates a different network, thus decreasing the alpha rhythm. Despite the difficulty of using a different NFB protocol and the fact that electroencephalographic changes were not consistent between the studies, cognitive improvement was a common finding for all of them. A possible explanation for this improvement could be the multiple factors involved in NFB treatment. One of the limitations of this study is its small sample size; in particular, the Sham group included only five subjects. Unfortunately, the COVID-19 pandemic prevented other children diagnosed with RD and EEG delayed maturation from receiving the placebo treatment. However, it should be mentioned that the sample size of the NFB group in this study is larger than that of the other NFB studies aimed at treating RD that preceded it.