Loss of cells

FTD is marked by cell loss and scarring, called atrophy, in the frontal lobes, parts of the temporal lobes and the deeper brain structures that link to them. The tissue loss results from changes in the proteins that normally help cells function. When proteins change shape or quantity (either too much or too little), they no longer function normally and then the cells that depend on those proteins can no longer function normally either. If a cell or a protein is dysfunctional, the body destroys it. When enough cells in a specific brain area are lost, then you see the signs and symptoms of disease.

The frontal lobes manage the executive functions - the ability to act appropriately in social situations, make plans and reason through ideas - as well as aspects of personality and creativity. The temporal lobes are involved predominantly in memory, speech and language. The cell loss in these areas leads to the particular signs and symptoms of frontotemporal dementia, semantic dementia and progressive nonfluent aphasia.