Senile dementia is a longterm degenerative condition . It does not make sense that giving people a short course of vitamin D could make a difference . Does it in some way cause regeneration of damaged neurons? Many things such as head injuries , various drugs ,such as ritilan and benzodiazapam, cause senile dementia . Because the brain and nervous system do not repair themselves significantly we should focus on preventing the brain damage resulting in senility rather than trying to fix it