Hamilton C, Hamilton D, Nicklason F, El Massri N, Mitrofanis J. Exploring the use of transcranial photobiomodulation in Parkinson's disease patients. Neural Regen Res 2018;13:1738-40

This article summarises the early findings of people with Parkinson’s disease using light hats and focuses on what is likely to be happening in the brain. It is a bit technical, but it is one of the very first journal articles considering  the significant implications the results from these case studies.