Power The bioactivity of IGF in cerebrospinal fluid in patients with dementia have not earlier been determined. Pilot data indicate that bioactivity from IGF-II in healthy people(n= 9) is 57 ± 13 ng/ml(mean ± SD). If the difference in a patient group is set to 26ng/ml ( ̴ 2 x SD) then inclusion of 10 persons per group give the project a power of 90% by use of ANOVA and a significant level of 5 %. It has therefore been chosen to include 15 patients in the project.