Executive Cognitive Function In CADASIL Patients May Be Improved By Taking Donepezil, donepezil may improve the executive function of patients who suffer from the CADASIL form of vascular dementia. However, researcher Martin Dichgans of Ludwig Maximilian University, Munich, Germany and colleagues found that donepezil did not improve patients' cognitive score.eukoencephalopathy) is a genetic form of vascular dementia (due to vascular lesions in the brain) and the most common form of hereditary stroke disorder. It tends to begin with migraine headaches and strokes in middle-aged patients. Executive functions are the high-level cognitive processes that facilitate new ways of behaving, and optimize one's approach to unfamiliar circumstances.