Neurodegenerative diseases include multiple disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, polyQ diseases including Huntington's disease, spinocerebellar ataxias, and others. The worldwide prevalence of several notable neurodegenerative diseases is depicted in Figure , along with the number of documents related to these diseases in the CAS Content Collection , the largest humancompiled multi-disciplinary database of published documents and substances.