Do blood thinners like aspirin or warfarin help in slowing down vascular dementia caused by mini strokes that is caught at a very early stage?

Doubtful.: Theoretically, there is empirical hope. However, no existing scientific evidence supporting decreased rate of small blood vessel occlusion supplying vital cerebral areas has been performed. Prevailing wisdom suggests multi factorial mechanisms as etiology.

Vascular Dementia : There has been no evidence to suggest that blood thinners, such an anti-platelet agents (e.g. Aspirin, plavix) or anticoagulants such as coumadin, (warfarin) slow down the progression of vascular dementia. Aspirin is good for general cardiovascular health, but there is no medical data to support it's use in preventing or slowing dementia. You could still consider Aspirin for your cv health if recommended.