A null result does not always mean that the independent variable (the factor manipulated by the researcher) does not affect on the dependent variable (the outcome being measured).

The presence of diffuse beta is not inherently abnormal, but it does merit clinical consideration. It may reflect endogenous factors such as individual variability in cortical excitability, exogenous factors such as the use of CNS-active medications (e.g., benzodiazepines, barbiturates, certain anesthetics), or non-cerebral factors such as EMG contamination.

Not all slow alpha is a pathological sign. A subset of these slow rhythms, especially when reactive and morphologically stable, represents not a degradation of function but a subharmonic of the canonical posterior dominant rhythm (PDR), generated by the same resonant thalamocortical loop but oscillating at half the fundamental frequency.