***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Subjects with a mild cognitive impairment ( MCI ) have a memory impairment beyond that expected for age and education yet are not demented . These subjects are becoming the focus of many prediction studies and early intervention trials . OBJECTIVE To characterize clinical ly subjects with MCI  cross-sectionally and longitudinally . DESIGN A prospect i ve , longitudinal inception cohort . SETTING General community clinic . PARTICIPANTS A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease ( AD ) , all from a community setting as part of the Mayo Clinic Alzheimer 's Disease Center/Alzheimer 's Disease Patient Registry , Rochester , Minn. MAIN OUTCOME MEASURES The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the  Mini-Mental State Examination , Wechsler Adult Intelligence Scale-Revised , Wechsler Memory Scale-Revised , Dementia Rating Scale , Free and Cued Selective Reminding Test , and Auditory Verbal Learning Test .  Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders , Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer 's Disease and Related Disorders Association criteria , respectively . RESULTS The primary distinction between control subjects and subjects with MCI was in the area of memory , while other cognitive functions were comparable . However , when the subjects with MCI were compared with the patients with very mild AD , memory performance was similar , but patients with AD were more impaired in other cognitive domains as well . Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD . CONCLUSIONS Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD . They appear to constitute a clinical entity that can be characterized for treatment interventions BACKGROUND Defining the nature of the contribution of stroke to cognitive impairment remains challenging . OBJECTIVE To describe associations between stroke history , APOE genotype , and subtypes of mild cognitive impairment ( MCI ) . METHODS We r and omly selected residents from Olmsted County , Minnesota , aged 70 to 89 years on October 1 , 2004 , and invited eligible subjects without documented dementia to participate . Participants ( n = 2050 ) were evaluated through an informant interview , a neurological evaluation , and neuropsychological testing . Neuropsychological testing included 9 tests to assess memory , attention , executive function , visuospatial cognition , and language . Subjects were diagnosed by consensus as cognitively normal or as having MCI ( either amnestic or nonamnestic ) or dementia . A history of stroke was obtained from the subjects and confirmed in their medical records . We computed the odds ratios ( ORs ) for a clinical diagnosis of MCI or for scoring in the lowest quartile on each cognitive domain . RESULTS There were 1640 cognitively normal subjects and 329 subjects with MCI : 241 with amnestic MCI and 88 with nonamnestic MCI . In fully adjusted models with only subjects without dementia , a history of stroke was associated with a higher OR of nonamnestic MCI  ( OR , 2.85 ; 95 % confidence interval [ CI ] , 1.61 - 5.04 ) than amnestic MCI ( OR , 1.77 ; 95 % CI , 1.14 - 2.74 ) . A history of stroke was also associated with impaired function in each cognitive domain except memory . The association was strongest for attention and executive function ( OR , 2.48 ; 95 % CI , 1.73 - 3.53 ) . APOE epsilon4 genotype was associated only with amnestic MCI and with impaired memory function . CONCLUSIONS In this population -based sample of persons without dementia , a history of stroke was particularly associated with  nonamnestic MCI and impairment in nonmemory cognition . The APOE epsilon4 genotype was associated with memory impairment and amnestic MCI This individual differences study examined the separability of three often postulated executive functions-mental set shifting ( " Shifting " ) , information updating and monitoring ( " Updating " ) , and inhibition of prepotent responses ("Inhibition")- and their roles in complex " frontal lobe " or " executive " tasks . One hundred thirty-seven college students performed a set of relatively simple experimental tasks that are considered to predominantly tap each target executive function as well as a set of frequently used executive tasks : the Wisconsin Card Sorting Test ( WCST ) , Tower of Hanoi ( TOH ) , r and om number generation ( RNG ) , operation span , and dual tasking .  Confirmatory factor analysis indicated that the three target executive functions are moderately correlated with one another , but are clearly separable . Moreover , structural equation modeling suggested that the three functions contribute differentially to performance on complex executive tasks . Specifically , WCST performance was related most strongly to Shifting , TOH to Inhibition , RNG to Inhibition and Updating , and operation span to Updating . Dual task performance was not related to any of the three target functions . These results suggest that it is important to recognize both the unity and diversity of executive functions and that latent variable analysis is a useful approach to study ing the organization and roles of executive functions OBJECTIVES To investigate whether  mild cognitive impairment ( MCI )  with multiple impaired cognitive domains ( mcd-MCI ) is a prodromal manifestation of vascular dementia ( VaD ) . DESIGN Prospect i ve cohort study . SETTING Geriatric unit of the Ospedale Maggiore Istituto di Ricovero e Cura a Carattere Scientifico , Milan , Italy . PARTICIPANTS Four hundred community-dwelling subjects aged 65 and older who came freely to the geriatric unit as part of a comprehensive geriatric assessment program were evaluated for memory impairment or other cognitive disorders . Subjects with MCI  were kept under observation for 3 years . MEASUREMENTS Subjects with MCI  were studied by applying a st and ardized clinical evaluation and a conducting a computed tomography brain scan .  Cognitive performance was assessed using the  Mini-Mental State Examination  , the  Clock Drawing Test  , and a  comprehensive battery of neuropsychological tests . Cardiovascular comorbidity was assessed on the basis of medical history and using electrocardiography , echocardiography , and carotid color Doppler ultrasound . RESULTS MCI was found in 65 of the 400 community-dwelling subjects ; 31 were classified with amnestic MCI ( a-MCI ) and 34 with mcd-MCI . A dysexecutive syndrome characterized people with mcd-MCI , who had significantly more vascular comorbidity and signs of vascular disease on brain imaging as well as a higher prevalence of extra pyramidal features , mood disorders , and behavioral symptoms than people with a-MCI . Twenty of the 65 subjects with MCI ( 31 % ) progressed to dementia within 3 years of follow-up : 11 subjects with Alzheimer 's disease ( AD ) and nine with VaD. All patients who evolved to AD had been classified with a-MCI at baseline , whereas all patients who evolved to subcortical VaD had been classified with mcd-MCI at baseline . CONCLUSION All subjects who converted to subcortical VaD had been classified with mcd-MCI , suggesting that mcd-MCI might be an early stage of subcortical OBJECTIVES To identify non-demented individuals with cognitive impairment due to a cerebrovascular etiology among those coming to observation of a memory clinic and to describe their clinical features and outcome . METHODS Patients were enrolled in a prospect i ve study on early cognitive impairment carried out in a Memory Clinic . Mild cognitive impairment of the vascular type ( MCI-V ) was defined based on modified criteria for subcortical vascular dementia ( SVD ) by Erkinjuntti and colleagues . Twenty-nine patients with MCI-V ( age 78 + /- 7 , Mini Mental State Exam ( MMSE ) 24 + /- 3 ) were compared with 14 with mild cognitive impairment of degenerative etiology ( MCI ) based on the Mayo Clinic criteria ( age 72 + /- 9 , MMSE 25 + /- 2 ) , and to 21 patients with frank SVD ( age 80 + /- 6 , MMSE 21 + /- 3 ) . Patients were followed over time for 32 + /- 8 months . RESULTS MCI-V patients had a neuropsychological profile characterized by poor performance on frontal tests ( Wisconsin card sorting and word fluency ) and neurological features of parkinsonism without tremor ( impairment of balance and gait ) . Of those followed for at least 40 months , 50 % of patients with MCI-V and SVD had died , while all MCI patients were still alive ( P = 0.03 ) . Of those alive , 68 % of the MCI-V , 52 % of the SVD , and 17 % of the MCI patients had reached one of the following outcomes at 40 months : nursing home placement , functional loss , and cognitive deterioration ( P = 0.02 ) . CONCLUSIONS Patients with MCI-V have a distinctive clinical picture and can be identified in a clinical setting . Because of the high frequency of adverse outcomes , very early preventive measures need to be devised Little is known about progression , short of dementia , in vascular cognitive impairment . In the Canadian Study of Health and Aging , 149 participants ( 79.3 ± 6.7 years ; 61 % women ) were found to have vascular cognitive impairment , no dementia ( CIND ) . After 5 years , 77 participants ( 52 % ) had died and 58 ( 46 % ) had developed dementia . Women were at greater risk of dementia ( OR 2.1 , 1.0 to 4.5 ) . Of 32 participants alive without dementia , cognition had deteriorated in seven and improved in four . Half of those with vascular CIND developed dementia within 5 years , suggesting a target for preventive interventions OBJECTIVES Our aims were to 1 ) detect the occurrence of three mild cognitive impairment ( MCI ) subtypes in the general population ; 2 ) identify cases of cognitive impairment which are not detected by current operational criteria for MCI and ; 3 ) determine the predictive value of the subtypes for identifying future Alzheimer disease ( AD ) . DESIGN Three-year prospect i ve study . SETTING Population -based Swedish study , the Kungsholmen Project . PARTICIPANTS Three hundred seventy-nine nondemented older adults aged 75 - 95 . MEASUREMENTS St and ard plus modified MCI criteria were applied at baseline . In the modified definitions , the requirement for normal general cognition was removed . A category for persons without MCI who had only global cognitive deficits was added . Three-year progression to AD was assessed ( DSM-III-R criteria ) . RESULTS Occurrence per 100 nondemented persons of  MCI-amnestic , MCI-multidomains , and MCI-single-nonmemory  was 2.1 % , 1.8 % , and 7.2 % , respectively . When applying modified definitions for  MCI-amnestic  and  MCI-multidomains  , the occurrence almost doubled . Seven percent of the sample had impairment on a global cognitive task but performed at normal levels on all other domain-specific tasks .  MCI-multidomains showed the highest progression to AD ( hazard ratio [ HR ] : 23.6 , 9.3 - 60.1 ) . MCI-amnestic reached similar predictivity only when using the modified definition ( HR : 17.9 , 6.8 - 46.9 ) . Even participants without MCI who had only global deficits had a ninefold risk of AD ( HR : 9.1 , 2.8 - 29.4 ) . CONCLUSIONS Two-thirds of MCI-multidomains , but only half of MCI-amnestic progress to AD . The st and ard MCI criteria failed to identify those people with global cognitive deficits who have , however , a high risk of progressing to AD 
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Results VaMCI cases had poorer performances on fronto-executive tasks , a higher prevalence of stroke , presence of periventricular and profound white matter hyperintensities on MRI images , as well as more extrapyramidal signs and behavioral symptoms .
Executive dysfunction might be associated with disconnection of fronto-parietal-subcortical circuits .
Progression to dementia was associated with baseline deficits in executive function , in simple sustained attention and language , and large periventricular WMH .
Discussion VaMCI develops with impairment in non-memory domains and subcortical white matter changes on MRI images , which are consistent with clinical and neuroimaging findings in