Mild cognitive impairment and preclinical Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized by a gradual decline of numerous cognitive processes, culminating in dementia. Mild cognitive impairment (MCI) is a relatively broad clinical condition involving a slight memory deficit, which in many cases represents a transitional state between normal cognition and AD. Much research is currently being conducted on MCI, since any therapy that is effective at treating this early manifestation of dementia may provide an opportunity for managing the disease while patient function is relatively preserved. Current research seeks to develop disease-modifying treatments that intervene in the pathobiologic processes involved in MCI and AD. Another goal of current research is to develop antecedent biomarkers that can be used to detect AD prior to the appearance of symptoms and before substantial and irreversible brain damage occurs.