# Neurofeedback Effects on EEG Connectivity among Children with Reading Disorders: I. Coherence
### NFB Studies Using Theta/Alpha Reduction Protocol
Cognitive scores significantly improved in the auditory group only. Two factors could be combined; on the one hand, an auditory stimulus usually takes 8-10 ms to reach the brain, whereas a visual stimulus takes between 20 and 40 ms [58]. This could explain why, in the auditory-NFB, the temporal contingency was greater. On the other hand, it is known that the eyes-closed condition promotes the production of alpha. Therefore, in the present study, auditory feedback was used. In the last study [59], differences in working memory were explored by comparing 10 children with learning disorders who received NFB treatment against 8 who received a sham NFB treatment. Both groups reduced their theta/alpha ratio. The group treated with NFB increased their response speed in the working memory task and showed electroencephalographic changes, indicating an improved recruitment of neural resources related to this cognitive process that is relevant for reading. In summary, the NFB protocol, which reinforces a reduction in the theta/alpha ratio at the lead with the most abnormal theta/alpha ratio, has been shown to reduce this ratio, indicating that children have acquired the learning that the NFB itself induces. However, this ratio has also been found to be reduced in children who received sham NFB treatment. However, this ratio has also been found to be reduced in children who received a sham NFB treatment, but this is not surprising. Various elements of an NFB protocol, such as the trained frequencies [60], the number of administered sessions [61], and the sensory modality of the reinforcer [46], are demonstrated to be essential for the outcomes. However, an NFB protocol and its associated sham NFB protocol share characteristics, such as the participants' expectancy, the use of metacognitive strategies [62], or the placebo effect [63; 64; 65], that can produce changes even in the EEG [66; 67]. Considering that the results of current sources are more reliable than scalp ones, it could be inferred that delta and theta activity diminished and alpha and beta activity increased after NFB using this protocol. This tendency toward electroencephalographic maturation, regardless of frequencies and regions trained, suggests a reorganization of the EEG [44]. As a consequence, cognitive improvement is observed whenever an auditory reward is used [44; 45; 46]. Although the cited studies are limited by their small samples, they were homogeneous because the participants were exquisitely selected by imposing rigorous inclusion criteria. This high homogeneity involves little intragroup variability. Although these restrictions allowed for a more profound study of learning disorders, the results cannot be generalized to the whole learning disorder population because a high comorbidity exists between learning disorders and other psychiatric pathologies. However, both large samples and theoretically precise dependent measures are necessary to evaluate the efficacy of a psychophysiological treatment [68]. This was a problem in most of the previous studies addressed in the current study. Criticisms about the low IQ of children with learning disorders are frequent. However, their low IQ should come as no surprise considering that these children not only have deficits in reading, writing, and arithmetic but also have alterations in executive functions, specifically in working memory [69], and all these abilities are considered in obtaining IQ scores. On the other hand, according to criterion D for classifying a learning disorder [7], an intellectual disability (IQ \(<\) 70 and impairment in everyday adaptive functioning) should be excluded. In these prior studies, changes in the AP and RP of EEG signals were explored. However, they refer to changes in neuronal activation of isolated areas; currently, neural networks and connectivity have provided a more realistic perspective in cerebral function research [70].