A Honor Society of Nursing (STTI) answered. Different forms of dementia affect your body differently, but in one way or another they all affect your brain. The most common form of dementia is Alzheimer' disease, which causes degeneration of brain tissue and nerve cells.Frontotemporal dementia also causes damage to nerve cells, but only in the frontal and temporal lobes of your brain.Lewy body dementia is caused by masses of protein in your brain known as Lewy bodies, and vascular dementia affects the arteries that move blood from your heart to your brain.Several other factors that ultimately result in damage to your brain cells or nerves may lead to other forms of dementia as well.rontotemporal dementia also causes damage to nerve cells, but only in the frontal and temporal lobes of your brain. Lewy body dementia is caused by masses of protein in your brain known as Lewy bodies, and vascular dementia affects the arteries that move blood from your heart to your brain.