P3‐244: Elevated Physiological Fluctuations in White Matter is Related to Disease Severity in Patients with Parkinson's Disease. (1st July 2016) - Shirzadi, Zahra; Sharmarke, Hanad; Robertson, Andrew D.; Metcalfe, Arron W.S.; Duff-Canning, Sarah; Marras, Connie; Lang, Anthony E.; Masellis, Mario; MacIntosh, Bradley J.