NNIPPS is a clinical trial of riluzole (a drug previously shown to slow down the rate of progression og amyotrophic lateral sclerosis-ALS; Lou Gehrig's disease) involving nearly 800 people diagnosed with the 'parkinson plus' syndromes of multiple system atrophy (MSA) and progressive supranuclear plasy (PSP). In addition to showing whether riluzole is helpful in MSA and PSP, NNIPPS will improve criteria for making an accurate and early diagnosis, for assessing the rate of progression, and will advance understanding of the biology of these disabling and progressive neurodegenerative diseases.