Dementia represents the most common neurodegenerative disorder affecting approximately 5% of the elderly population over age 65 years. At present, different forms of dementia are distinguished, including Alzheimer's disease (AD), dementia with Lewy bodies, frontotemporal dementia, corticobasal degeneration, progressive nuclear palsy and Parkinson dementia. Often, these atypical dementias are associated with neurological symptoms and with motor neuron disease. Understanding the molecular basis of these dementias, their diagnosis, clinical implications, and diagnostic issues, currently...