The concept of the boundary between normal aging and very early or mild Alzheimer's disease (AD) has become an area of interest for both theoretical and practical reasons. This is based on the assumption that mild cognitive deficits, particularly in the area of memory, are the precursors to the cognitive dysfunction that characterizes AD. Therefore, identification of early clinical AD has become an important public health priority as new treatments have emerged (1-3).Mild cognitive impairment (MCI) refers to a transitional state between the cognition of normal aging and very mild AD. Several studies have indicated that MCI individuals are at an increased risk for developing AD, ranging from 1% to 25% per year (4); 24% of MCI patients progressed to AD in 2 years (2) and 20% over 3 years (5), whereas a recent study indicated that the progression of MCI subjects was 55% in 4.5 years (1). A relatively long preclinical stage of dementia has been demonstrated, corresponding to a stage of the disease at which the pathology begins to have some repercussions on cognitive functioning, but when cognitive impairments are still not sufficient for the dementia criteria to be reached (6).In the past 20 years, several authors have attempted to find neuropsychological predictors of progression to AD. Collectively, these studies emphasize the need for the clinician to detect the earliest signs of cognitive impairment. This practice parameter is important to determine whether screening at-risk subjects in a specific setting leads to the diagnosis of dementia (7). Within this research context, specification of certain neuropsychological tests for the identification of MCI will certainly ensure comparability at this experimental stage as well as cross-national estimates of prevalence, incidence, risk, and associated morbidity.The value of neuropsychological measures in helping to identify very early cases of dementia has been documented by both cross-sectional and longitudinal studies. More specifically, deficits in Arna´iz E, Almkvist O. Neuropsychological features of mild cognitive impairment and preclinical Alzheimer's disease. Acta Neurol Scand 2003: 107 (Suppl. 179): 34-41. Ó Blackwell Munksgaard 2003.Recent research has identified a transitional state between the cognitive changes of normal aging and Alzheimer's disease (AD), known as mild cognitive impairment (MCI). MCI patients experience memory loss to a greater extent than one would expect for age, yet they do not meet currently accepted criteria for clinically probable AD. An issue currently under investigation is whether MCI represents the preclinical stages of AD or a distinct and static cognitive aetiology. In an attempt to address this issue, the present investigations are adopting a convergent approach to the detection of preclinical AD, where multiple risk factors are considered when making a diagnosis. Currently, one of the most important tools when assessing early cognitive changes is neuropsychological evaluation. MCI subjects typically record neuropsychological p...
