I would be happy to know your experience about „ratios” in neurofeedback. Only a few of them (Theta /Beta on Cz in ADHD, Frontal Alpha Asymmetry in Depression) are well discussed. On the neurofeedback courses conducted in Poland, there are very many of them, eg: Traumatic experiences: beta1 in T4 higher>2 times in T3 beta2 asymmetry in T3 / T4> 30% Depression, discouragement, lack of motivation: beta1 in T4 50% lower then in T3 Have you ever found similar strict indicators (more then 2 times, less then 30% etc...)? Maybe in book/article, maybe on your course? Give me such examples please!
I do ratios in HRV for better results but have not used them for qEEG analysis. If I did, I would try analyses both ways (analyze the numerator and denominator separately, then as a ration) and see which best approximates the data. Do not forget to clean your data (Tabachnick & Fidell).