Memantine (10mg BID) for the Frontal and Temporal Subtypes of Frontotemporal Dementia

The primary objective of the study is to determine whether memantine is effective in slowing the rate of behavioral decline in frontotemporal dementia. The secondary objective of the study is to assess the safety and tolerability of long-term treatment with memantine in patients with frontotemporal dementia (FTD) or semantic dementia (SD). To determine whether memantine is effective in slowing the rate of cognitive decline in frontotemporal dementia. To evaluate whether memantine delays or decreases the emergence of parkinsonism in frontotemporal dementia. The tertiary objective of the study is to determine whether treatment with memantine affects changes in weight