The rise in neurostimulation methods as potential treatments for neuropsychiatric diseases is encouraging (see Nature 555, 20–22; 2018). As president of the International Pharmaco Electroencephalogram Society, however, I question your suggestion to investigate how brainwaves might be manipulated to benefit patients.
Brainwaves are just the by-products of ongoing neuroelectrical interactions, so an underlying condition gives rise to anomalous patterns on electroencephalograms. Clinical interventions that target the faulty cellular mechanisms responsible will alter those brainwave patterns. This holds true for potential neurostimulation therapies, such as flashing lights and pink noise that you discuss.
In my view, manipulating the brainwaves themselves risks confusing cause and effect, so is unlikely to work as a treatment.
Nature 557, 309 (2018)