Cognitive impairment improves the predictive validity of the operational definition of frailty, because it increases the risk of adverse health outcomes in this particular subgroup of the elderly population.

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Objective: To investigate whether patients diagnosed as amnestic mild cognitive impairment (MCI) have also impairment in attention/executive functions and, therefore to clarify whether all subcomponents of executive control are equally affected in MCI.Background: MCI refers to the transitional state between normal ageing and dementia.Amnestic MCI is characterized by impaired episodic memory, although subtle impairment of executive functions has been noted on neuropsychological tests.Methods: We investigated 20 MCI patients and 20 normal controls using episodic memory, attention/executive functions, language and praxis tests. Results: MCI patients had a significantly lower scores on all measures of the Free and CuedSelective Reminding Test (p<0.05 to 0.01) than controls. Furthermore MCI had a greater number of perseverations (p<0.01) on Modified Card Sorting Test and the lowest performance on the Stroop test (p<0.02).Conclusion: Our findings showed impairment in episodic memory performance in MCI as compared to that of controls. In addition, MCI patients had problems with response inhibition, switching and cognitive flexibility which encompass various aspects of executive functions. This suggests that MCI may be identified by using a more detailed procedure for the assessment of cognitive decline than the evaluation of memory alone. IntroductionThe recent developments in drug treatments for Alzheimer's disease (AD) have highlighted the importance of early diagnosis and the need to characterize the cognitive profile of the earliest stages of the disease.Recent research has identified a transitional state between the cognitive changes of normal aging and AD, known as mild cognitive impairment (MCI). Other studies of MCI report cognitive deficits similar to those described by Petersen and colleagues. 5,6 However, in recent years, the literature has reported that, while memory is the hallmark of patients with amnestic MCI, they are impaired on a variety of tasks that have commonly been considered a measure of executive functions. reported recently that tasks requiring executive control are significantly affected in the preclinical phase of AD and are reliable predictors of the disease before diagnosis. The results of these studies emphasised the importance of attention and executive function in MCI patients. However, it must be pointed out that variability across studies in both tasks used to examine aspects of executive function, and in the MCI definition, makes it difficult to determine which aspects of executive control are affected in MCI. Consequently, we selected executive tasks more "universally" accepted like those mentioned in the abovecited studies. The objective was to avoid to further clouding the issues by introducing additional measures.The aims of our study were to investigate whether patients diagnosed as amnestic MCI have also impairment in attention/executive functions and, therefore to clarify whether all subcomponents of executive control are equally affected in MCI. Materials and methods ...

Reduced semantic fluency performances have been reported in the preclinical phase of Alzheimer's disease (AD). To investigate the cognitive processes underlying this early deficit, this study analyzed the verbal production of pre-demented subjects for the animals category with the qualitative parameters related to clustering (i.e. the ability to generate words belonging to semantic subcategories of animals) and switching (i.e. the ability to shift from one subcategory to another) proposed by Troyer.This qualitative analysis was applied to the PAQUID cohort, a 17-year longitudinal population-based study. The performances on the animal verbal fluency task of 51 incident cases of possible and probable AD were analyzed at the onset of dementia, 2 years and 5 years before dementia onset. Each case was matched for age, sex and education to two control subjects leading to a sample of 153 subjects. The mean cluster size and the raw number of switches were compared in the two samples. The results revealed a significantly lower switching index in the future AD subjects than in the elderly controls including 5 years before dementia incidence. A significant decline in this parameter was evidenced all along the prodromal phase until the clinical diagnosis of dementia. In contrast, the mean cluster size could not discriminate the two groups. Therefore the results support the hypothesis that impaired shifting abilities -rather than semantic memory storage degradation-could explain the early decline in semantic fluency performance occurring in the predementia phase of AD.

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