ROMANIAN JOURNAL OF NEUROLOGY – VOLUME VII, NO. 3, 2008 90 REVIEWS MILD COGNITIVE IMPAIRMENT (MCI) – CURRENT RELEVANCE OF THE CONCEPT R.D. Chirileanu, M. Simu, D. Reisz, C. Rosca, S. Males, R. Tocai Neurology Clinic „Victor Babes“ Medicine and Pharmacy University, Timisoara, Romania ABSTRACT The term ‘mild cognitive impairment’ has been introduced to represent the border between frank dementia and changes related to aging. How do the memory difficulties in MCI differ from those of normal aging? This is a very difficult question which has no permanent answer yet. This review discusses the definition of terms in the field of cognitive impairment and the relevance for current clinical settings and clinical trials. Key words: aging, cognitive impairment, dementia DEFINITION OF MILD COGNITIVE IMPAIRMENT Mild cognitive impairment (MCI) is a stage of transition between the cognitive decline of normal aging and more important problems which are caused by Alzheimer’s disease. The disorder presents a variety of symptoms. Memory loss is the predominant one, but many areas of thought and action can also be affected, for example: judgement, reasoning, language, attention, reading and writing. MCI was intended to capture the patients with the risk of developing dementia. Studies suggest that MCI affects 10-17% of the elderly population. Although not all MCI people will progress to more advanced stages of cognitive impairment, a part of them eventually develop Alzheimer’s disease. Some of them remain stable and others can even return to a normal state. MCI can be classified in: A) MCI: represents a heterogeneous condition including early dementia of multiple types; vascular MCI; reversible causes of multiple types of depression; the “worried well” and long lasting cognitive problems. This form presents: 1. evidence of cognitive impairment 2. preserved general cognitive abilities 3. not demented B) Amnestic MCI: was nominated as the earliest stage of Alzheimer’s disease and it is characterized by: 1. memory complaint 2. objective memory impairment 3. normal general cognition 4. not demented C) Operationalized amnestic MCI: represents people with risk of developing early Alzheimer’s disease: 1. memory complaint, verified by an informant 2. memory impairment, 1.5 standard deviations below normal (adjusted for age and education) 3. normal general cognition (mini-mental state score of 24 or above) 4. dementia not present as defined by preserved activities of daily living 5. clinical dementia rating of 0.5. EPIDEMIOLOGICAL STUDIES OF MCI Prevalence estimates for MCI show significant variability ranging from 2.8% to 23.4%. For example applying MCI criteria to a population which consists of individuals 60 years old and older led to MCI prevalence estimates of 3%. Another study defining MCI as impairment in visual memory with normal general cognitive function (MMSE score not <1SD below the mean) demonstrates the prevalence of MCI to be 2.8%. Another study showed that nearly 25% of individuals had some form of cognitive impairment. The exact criteria used to define MCI and the sample to which it is applied influence how broadly MCI Author for correspondence: Denisa Pirscoveanu, Neurology Department, Neuropsychiatry Clinical Hospital, Medicine and Pharmacy University, 129 Calea Bucuresti, Craiova, Zip Code 200620, Romania email: denisapirscoveanu@yahoo.com