In a number of neurodegenerative diseases, a change in the conformation of specific proteins occurs which is considered to be related to the development of the disease process. In general, a change in the protein conformation from a predominantly alpha-helical to a predominantly beta-sheet structure, due to genetic or environmental factors, leads to oligomerization of the proteins. In Alzheimer's and prion diseases, insoluble precipitates or plaques are often observed in vivo as a consequence of beta-fibril formation due to the polymerization of the proteins. In certain other neurodegenerative diseases, for example in Huntington disease, the beta-sheet oligomers may interact differently with other functional proteins compared to the monomeric proteins inducing the disease. Biophysical studies would provide information regarding the forces responsible for the oligomerization of these proteins and hence provide methods for detecting these diseases, leading eventually to therapeutic approaches.