Alzheimer disease: primary ischemia concept and promising therapy

The important role of cerebral blood flow (CBF) in Alzheimer disease (AD) has been increasingly recognized in recent years. An abundance of data (The Rotterdam Study, see text) has shown the decline of CBF velocity with transcranial Doppler, confirming earlier data obtained with the xenon133 method. In spite of these data, AD is still considered a neurodegenerative disorder with secondary CBF changes. This work is a critical evaluation of earlier literature because of cogent reasons for the adoption of a new concept of AD as a primary ischemic disorder. Reports of lacking correlation between severity of CBF deficit and degree of tissue damage or clinical findings serve as evidence for primary ischemia because of the incompatibility with the concept of secondary ischemia. The CBF deficit in is thought to be due to the human upright gait in heretopredisposed individuals. As to therapy and prevention, a very simple, cheap and promising treatment is suggested (head-down-therapy).