Mild cognitive impairment.

Mild cognitive impairment (MCI) describes a state of cognitive functioning that is below defined norms, yet falls short of dementia in severity. It exists across a cognitive continuum with borders that are difficult to define precisely. Within our "graying" western societies, its prevalence increases with age. A number of subtypes of MCI, including age-associated memory impairment (AAMI), age-associated cognitive decline (AACD), amnestic MCI (MCIa), and cognitive impairment not dementia (CIND) have contributed to our understanding of MCI. Recent efforts have been directed at developing a uniform diagnostic classification for MCI that reflects the maturation of knowledge about this state. There is considerable etiological and clinical heterogeneity within MCI; however, there is a unifying increased risk of progression to dementia. The diagnostic process for MCI involves assessment of multiple cognitive domains, with particular attention to episodic and semantic memory, while neuroimaging with structural MRI and PET both add to the diagnostic and prognostic evaluation of MCI. Although there are no pharmacological treatments at present that are capable of delaying the long-term progression of MCI to dementia, there is some evidence of short-term symptomatic benefits with acetylcholinesterase inhibitors. MCI is an important clinical problem, which clinicians can expect to face with increasing frequency. The essentials of management include a thorough assessment directed at etiological determination and counseling and judicious use of available therapeutics.