This invention is a method and kit for treating a disease associated with, or resulting from, the accumulation of soluble oligomer amyloid beta 1-42 using an antibody, or antibody fragment thereof, that has a higher affinity for amyloid beta 1-42 oligomers than for amyloid beta 1-42 monomer, amyloid beta 1-40 monomer, plaques and amyloid beta fibrils and, optionally, a tau therapeutic or an inhibitor of amyloid beta production or aggregation.