Alzheimer's disease (AD) and Lewy body disorders (LBDs) are the two most important reasons for neurodegenerative dementia syndromes. Due to an aging population and other demographic changes, prevalence of these neurodegenerative diseases is steadily increasing. This leads to growing social and economic burden. Basically only symptomatic treatments for these disorders are presently available. However, intensive research in these fields gives reasonable hope for neuromodulatory, neuroprotective and disease-modifying therapies to become soon a reality. The evaluation of such therapies is, however, heavily dependent on existence of reliable diagnostic and prognostic biomarkers for early detection and evaluation of the stages of the disease, defining the rate of disease progression prior to and following existing and future therapeutic interventions. Current biomarkers of these devastating neurodegenerative diseases are not sufficient for these purposes as the neurodegenerative processes start long before appearance of clinical symptoms. Candidate biomarkers for a preclinical diagnosis are strongly required. Hence, there is an urgent need for development, characterization, and improvement of such new and hopefully multifaceted biomarkers. For this special issue, we invite investigators to contribute original research articles as well as review articles that will stimulate the continuing efforts to develop and improve all kinds of biomarkers for these two neurodegenerative diseases. We are particularly interested in articles describing new methodological approaches and new hypothesis which would stimulate biomarker approaches in AD and LBD. However, studies investigating the validity of the existing biomarkers or combinations of them are also welcome. Potential topics include, but are not limited to:

• Recent developments in neurochemical biomarkers
• Recent developments in imaging biomarkers
• Recent developments in genetic markers
• Recent developments in multimodal approaches