# Neurofeedback Effects on EEG Connectivity among Children with Reading Disorders: I. Coherence
## 4 Discussion
### NFB Effects on Coherence in Children with RDs  
Previous studies have reported that NFB-induced learning occurs in approximately 80% of treated individuals [45]. In this study, a significant reduction in the theta/alpha ratio was demonstrated in the lead used to guide NFB. In total, 90% of the participants exhibited a reduction in this quotient, and 55% achieved normalization. This suggests that most individuals achieved learning that was induced by the NFB treatment. Additionally, in the Sham group, a significant reduction in the theta/alpha ratio was observed in the derivation with the most abnormal value; however, this reduction was significantly greater in the NFB group, suggesting that NFB-specific learning was responsible for a portion of this decrease in the NFB group. The remaining decrease found in both groups could be attributed to several uncontrolled factors, independent of the operant conditioning on which the NFB is based, for example, the use of metacognitive strategies, which have the potential to modify the EEG independently of the contingency between the EEG and the delivery of rewards [66; 67]. Other factors involved could be an expectation effect [62] or a placebo effect [63; 64; 65]. Additionally, it is important to remember the lifestyle changes experienced by both groups as a result of their participation in the study, including a friendlier approach from parents and teachers. However, in this study, the placebo treatment did not resemble the effects produced by the real NFB treatment, as [PERSON] and [PERSON] state [95]. Our results confirm the hypotheses regarding a reduction in delta and theta coherences in the NFB group. There was a significant reduction in delta coherence between right central and temporal regions and between frontopolar leads; furthermore, there was a significant reduction in the theta frequency band between the left frontal regions and other regions of the same hemisphere, between frontal areas of the right hemisphere, and between frontal, parietal, and posterior-temporal homologous areas. Although it was not proposed as a related hypothesis, a reduction was also observed in the beta band in the right hemisphere between frontal leads, parietal and temporal regions, and frontopolar homologous regions. However, when the involved regions were explored, the results only supported the theta coherence reduction between the left frontal and temporoparietal regions. The superior longitudinal fasciculus connects the frontal areas and temporoparietal areas. The integrity of these areas and their connection are related to adequate accuracy in reading words and pseudowords. As a consequence, this may produce better reading comprehension. In this study, children with RDs treated with NFB improved their reading accuracy and comprehension. An increase in alpha coherence was also observed in the NFB group between the parietal and occipital areas of the left hemisphere. This finding could be explained by the relationship between specialized areas of the ventral posterior circuit, which includes the visual word form area (VWFA), and the left dorsal temporoparietal circuit, which is specialized in phonological functions. An improvement in these connections may also explain their better performance in reading accuracy. In addition, a reduction in beta coherence between regions of the right hemisphere with frontal dominance was observed in the NFB group. This change, added to other changes in the right hemisphere or changes in the connections between homologous areas of the brain hemispheres, could be due to compensatory mechanisms necessary to improve reading. The role of the right hemisphere in prosody should not be forgotten; injury to the right temporal lobe has been referred to as a cause of deficits in reading rhythm [96; 97], which could have a negative effect on reading comprehension. As expected, NFB likely produces a reorganization of brain interconnections. Therefore, these results indicate a trend toward the normalization of coherence patterns in treated children.