# A Wireless EEG System for Neurofeedback Training
## 4 Materials and Methods
### Results
#### 4.6.3 z-NF Training Results
The \(\alpha/\theta\) scores of all post-training dyslexic sensors were significantly higher relative to the correspondent sensors of the preD group (postD vs. preD: \(p\)\(<\) 0.008, \(\chi^{2}\)\(>\) 7.02; Figure 7 and Table 4). There were no differences at the occipital and temporal cortices between the preD and postD z-scores at O1 and FT9-FT10 (low) and at TP8-O2 (high contrast). For both conditions, the right-hemispheric \(\alpha/\theta\) scores of the controls and dyslexic children before training were significantly higher than the left-hemispheric scores (left vs right side: \(p\)\(<\) 2.3 \(\times\) 10\({}^{-6}\), \(\chi^{2}\)\(>\) 31.2; Table 4), whereas a non-significant hemispheric difference in the post-training dyslexic group was found (postD left vs right side: \(p\)\(>\) 0.131, \(\chi^{2}\)\(<\) 2.29; Table 4). In a condition of low-contrast discrimination, the highest \(\alpha/\theta\) scores were found in the postD group at FT10, TP7, Pz, PO7, which covered the anterior and middle temporal, superior parietal, and middle occipital areas, in the Con group at TP8, PO8, and Oz, and the preD group at FT10, Pz, PO8, and O2 (Table 4) among the sensors in a group. In the high-contrast discrimination, the highest \(\alpha/\theta\) scores were found for the postD group at PO7, Pz, and Cz, in the Con group at Cz, TP8, and O1-O2, and in the preD group at the PO8 and O1 across the sensors in a group (Table 4). Lower \(\alpha/\theta\) z-scores at areas adjacent to the precentral gyrus and bilateral cuneus (Cz and Oz under high contrast) were found in the preD group compared with the Con group, similar to the reading tasks [6]. The preD \(\alpha/\theta\) scores were elevated at the anterior temporal cortex, related to efforts by compensatory mechanisms for the deficits in visual and motor processing (Figure 7). The postD group improved the \(\alpha/\theta\) oscillations at the premotor, primary motor, right anterior temporal, right occipitotemporal (TPS), and left middle occipital (PO7) cortices due to their more active involvement in the NF sessions (Figure 7). The Con vs. postD group comparisons showed that the qEEG z-NF also produced better effects in the occipital, middle temporal, and precentral areas of the controls (low contrast: TP8 and Oz; high contrast: O1-2 and Cz; Table 4). The sensor statistics for the postD group (vs. Con) yielded significantly higher \(\alpha/\theta\) scores at the SPL, left MOG, the MFG (low contrast: Pz and PO7; high contrast: Fz) and lower \(\alpha/\theta\) scores at the right middle occipital cortex (high contrast: PO8-O2). The middle temporal, lateral occipitotemporal, dorsal associative visual, and occipital areas in the post-training children with DD contributed to the compensatory \(\alpha\) and \(\theta\) mechanisms, reducing right-hemispheric dominance over the left. The intra-hemispheric \(\alpha/\theta\) scores significantly increased at the middle temporal and occipital cortices (both conditions: TP7 and PO7) and the middle frontal, precentral, and superior parietal cortices (low contrast: Fz, Cz, and Pz) for the post-training group (vs. Con and preD).