The patients will be tested in relevant tests of cognitive function at inclusion and after 16 weeks. At inclusion the patients will be tested in Mini Mental State Examination (MMSE) and Geriatric depression scale (GDS) to make sure that the patients meet the inclusion criteria. At inclusion and after 16 weeks the patients will be tested in Word List Memory Word List Recall Word List Recognition, Trail Making Test A + B and Stroop Word and Colour test.