***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: Cerebral white matter lesions ( WMLs ) have been associated with cognitive dysfunction . Whether periventricular or subcortical WMLs relate differently to cognitive function is still uncertain . In addition , it is unclear whether WMLs are related to specific cognitive domains such as memory or psychomotor speed . We examined the relationship between periventricular and subcortical WMLs and cognitive functioning in 1,077 elderly subjects r and omly sample d from the general population . Quantification of WMLs was assessed by means of an extensive rating scale on 1.5‐T magnetic resonance imaging scans . Cognitive function was assessed by using multiple neuropsychological tests from which we constructed compound scores for psychomotor speed , memory performance , and global cognitive function . When analyzed separately , both periventricular and subcortical WMLs were related to all neuropsychological measures . When periventricular WMLs were analyzed conditional on subcortical WMLs and vice versa , the relationship between periventricular WMLs and global cognitive function remained unaltered whereas the relationship with subcortical WMLs disappeared . Subjects with most severe periventricular WMLs performed nearly 1 SD below average on tasks involving psychomotor speed , and more than 0.5 SD below average for global cognitive function . Tasks that involve speed of cognitive processes appear to be more affected by WMLs than memory tasks . Ann Neurol 2000;47:145–151 Background and Purpose — Cerebral white matter changes ( WMC ) and lacunar infa rct are both believed to be consequence of small vessel disease . Whether the extent of WMC affect the type and degree of cognitive impairment in patients with lacunar infa rct is not clear . The study was undertaken to determine if WMC influences cognition in patients with lacunar infa rcts . Methods — We recruited consecutive patients who were admitted to the acute stroke unit because of acute lacunar infa rcts , mainly documented by diffusion-weighted magnetic resonance imaging . WMC were measured qualitatively and quantitatively . Patients were divided into quartiles according to the distribution of the volume of WMC . Cognition was assessed 12 weeks after stroke by psychometric tests  ( Chinese version of Mini-Mental State Examination [ MMSE ] , Alzheimer ’s Disease Assessment Scale-cognition [ ADAS-cog ] , Mattis Dementia Rating Scale-Initiation/ Perseveration subscale [ MDRS I/P ] ) and was compared between patients with varying severity of WMC . Multivariate linear regression analysis was performed to find variables that influenced performance in the psychometric tests . Results — Among the 94 included patients with acute lacunar infa rcts , those patients ( n=25 ) within the highest quartile of WMC were older , had more lacunar infa rcts , more severe stroke , and lower prestroke cognitive function compared with those with less WMC . In addition , their performances in psychometric tests were significantly more impaired . Multivariate linear regression analysis revealed that WMC significantly influenced performance in MDRS I/P. WMC did not independently influence performance in MMSE and ADAS-cog . Conclusions — Extent of WMC appears to be associated with executive dysfunction in stroke patients with lacunar infa rcts . Further large prospect i ve studies with extensive scales of executive function testing are required to confirm this issue We compared the performance of 40 patients with frontal lobe dementia to that of 40 patients with subcortical vascular dementia ( 80 patients including , 46 men and 34 women ) in a set of tasks assessing  attentional , executive , and behavioural tasks .  The frontal lobe dementia represents an important cause for degenerative disruption and is increasingly recognised as an important form ( up to 25 % ) of degenerative dementia among individuals of late-middle-age . The main involvement is the frontal-subcortical pathway , which is the final target of impairment even in subcortical vascular dementia . A wider involvement of the cortical ( decisional ) layers in frontal dementia , in contrast with the prominent and widespread involvement of the subcortical pathways ( refinement and corrections programs ) creates the different profiles of the two groups . Frontal patients have more difficulties in abstract reasoning , focusing attention , and implementing strategies to solve problems . They exhibit more profound behavioural alterations in personality and social conduct and show only moderate depression , and a total lack of insight concerning their clinical condition . In contrast , the patients with subcortical vascular dementia have poor general cognitive functions , high insight , and important depression and apathy as the principal and most salient characteristic of their behavioral conduct Differentiating the cognitive effects of cerebrovascular disease , particularly small vessel disease , from those of Alzheimer 's disease is a difficult clinical challenge . An influential model of how subcortical cerebrovascular disease causes cognitive dysfunction posits that damage to frontostriatal loops impairs frontal lobe function , leading to predominant impairment of executive function and secondary impairments of associated cognitive functions such as memory . Consistent with this , neuropsychological studies of clinical ly diagnosed patients have reported that individuals with vascular dementia do better on memory tests and worse on executive function tests compared with patients with Alzheimer 's disease . This observation has led to the suggestion that predominant cognitive executive dysfunction might serve as a useful diagnostic marker for vascular dementia . We sought to test this idea in a series of cases with autopsy-defined pathologies . Subjects were 62 autopsied cases from a prospect i ve study of vascular contributions to dementia . Using neuropathological features alone , 23 were diagnosed with Alzheimer 's disease ( AD ) , 11 with cerebrovascular disease ( CVD ) , 9 with both ( mixed pathology ) and 19 with normal elderly brain ( NEB ) . Three psychometrically matched composite scales of different cognitive abilities were used : Verbal Memory , Nonverbal Memory and Executive Function . Analysis of group data showed that for Alzheimer 's disease memory scores were lower than Executive Function by nearly a st and ard deviation on average . In contrast , and contrary to the model , CVD was rather equally impaired on Executive Function , Verbal Memory and Nonverbal Memory . Individual patterns of cognitive impairment were examined by defining three profiles based on reliable differences between neuropsychological scores to characterize cases with predominant memory impairment , predominant executive dysfunction , and ' other ' patterns . Analysis of individual impairment profiles showed that predominant memory impairment was present in 71 % of Alzheimer 's disease while predominant executive dysfunction described only 45 % of CVD . A stronger pattern emerged when cognitively normal cases were excluded ; among the six cognitively impaired CVD patients four had predominant executive dysfunction and none had predominant memory impairment . This report , comprised of a substantial sample of autopsy confirmed cases , delineates the patterns of neuropsychological impairment associated with small vessel cerebrovascular disease and Alzheimer 's disease While the findings show that memory loss usually exceeds executive dysfunction in patients with Alzheimer 's disease , the reverse is not the case in CVD . Taken as a whole , the results indicate that the cognitive effects of the small vessel cerebrovascular disease are variable and not especially distinct , thus raising question about the utility of executive impairment as a diagnostic marker for vascular dementia Two cancellation/attentional tasks : ( i ) Lines Cancellation ( LC ) and Multiple Features Targets Cancellation ( MFTC ) and ( ii ) a st and ard battery of neuropsychological tests , the Mental Deterioration Battery ( MDB ) , were administered to 68 patients with dementia of the Alzheimer 's type ( DAT ) and 40 patients with multi-infa rct dementia ( MID ) , who were accurately matched for the overall severity of dementia , and to 40 normal controls . Both accuracy and time of execution were considered in evaluating performance on the two cancellation tasks , which involved visuospatial exploration and psychomotor speed , but were differently dem and ing in terms of selective attention . On the first cancellation task ( LC ) , requiring a lower attentional load , the two demented patient groups performed at the same level of accuracy . On the second cancellation task ( MFTC ) , which was more dem and ing in terms of selective and divided attention , DAT patients were significantly less accurate than MID patients , making a higher number of ' false-alarm ' errors . Conversely , the time employed in the execution of both LC and MFTC took longer for MID than for DAT patients , suggesting a greater impairment of psychomotor speed in MID . In the MDB , DAT patients scored significantly worse than MID patients on several measures of episodic memory ( the immediate recall , delayed recall and delayed recognition of Rey 's Auditory Verbal Learning Test ) and on a test of visual-spatial memory . These data suggest that , while psychomotor speed and the lower ( sensorimotor ) levels of attention are preferentially impaired in subcortical forms of dementia such as MID , the higher levels of selective and divided attention are more markedly disrupted in the Alzheimer type of dementia Cerebral small-vessel disease is common in older people and may contribute to the development of dementia . The objective of the present study was to evaluate the relationship between measures of cerebral small-vessel disease on MRI and the rate of decline in specific cognitive domains in participants from the prospect i ve , population -based Rotterdam Scan Study . Participants were 60 - 90 years of age and free from dementia at baseline in 1995 - 1996 .  White matter lesions ( WML ) , cerebral infa rcts and generalized brain atrophy were assessed on the baseline MRI . We performed  neuropsychological testing at baseline and repeatedly in 1999 - 2000 and in 2001 - 2003 . We used r and om-effects models for repeated measures to examine the association between quantitative MRI measures and rate of decline in measures of global cognitive function , information processing speed , executive function and memory . There were a total of 2266 assessment s for the 832 participants in the study , with an average time from the initial to last assessment of 5.2 years . Increasing severity of periventricular WML and generalized brain atrophy and the presence of brain infa rcts on MRI were associated with a steeper decline in cognitive function . These structural brain changes were specifically associated with decline in information processing speed and executive function . The associations between MRI measures of cerebral small-vessel disease and cognitive decline did not change after additional adjustment for vascular risk factors or depressed mood . After exclusion of participants with an incident stroke , some of the associations of periventricular WML , brain infa rcts and generalized brain atrophy with measures of information processing speed and executive function were no longer significant . This may indicate that stroke plays an intermediate role in the relationship between cerebral small-vessel disease and cognitive decline . Our results suggest that in older people cerebral small-vessel disease may contribute to cognitive decline by affecting information processing speed and executive function In Western countries , vascular dementia ( VaD ) is the most common form of cognitive deterioration after Alzheimer 's disease . Therapeutic trials in VaD have so far failed to yield satisfactory results . One explanation of this failure may be the etiological and clinical heterogeneity of the included patients . Patients with subcortical VaD , defined on a clinical and radiological basis , may constitute a more homogeneous group . Thus , we conducted a post-hoc subgroup analysis of the Sc and inavian Multi-Infa rct Dementia Trial that evaluated the efficacy and safety of oral nimodipine administered for 6 months in 259 patients . The original patients sample was divided on the basis of head CT in those with subcortical VaD ( n=92 , 45 nimodipine , 47 placebo ) and those with multi-infa rct dementia ( n=167 , 83 nimodipine , 84 placebo ) . While in the total trial population a treatment effect could not be proved , in this subgroup analysis , the subcortical VaD patients treated with nimodipine performed better on the majority of neuropsychological tests and functional scales in comparison with patients on placebo . No trend could be evidence d in the multi-infa rct dementia patients . Treatment efficacy was in particular suggested for the Zahlen-Verbindungs-Test , Fuld-Object-Memory Evaluation , Word Fluency , and for the Instrumental Activities of Daily Living scale . The results did not reach statistical significance in this small sample . Our study preliminarily indicates that nimodipine could be effective in patients with small vessel subcortical VaD and supports the rationale for a further controlled and adequately powered trial to test nimodipine in patients with subcortical BACKGROUND White-matter hyperintensities are commonly found on magnetic resonance imaging ( MRI ) of elderly people with or without dementia . Studies of the relation between severity of white-matter hyperintensities and cognitive impairment have had conflicting results . We undertook a longitudinal study of age-related decline in intellectual function and MRI at age 80 years . METHODS From a cohort of 698 people born in 1914 and living in seven municipalities in Denmark , 68 healthy non-demented individuals had been tested with the Wechsler adult intelligence scale ( WAIS ) at ages 50 , 60 , and 70 , and they agreed to further WAIS testing at age 80 , and cerebral MRI at age 80 - 82 ( mean age 82.3 years ) . We scored separately the numbers of periventricular and deep white-matter hyperintensities . FINDINGS Scores for periventricular hyperintensities in this sample included all possible degrees of severity , but no participant scored more than 75 % of maximum for deep white-matter hyperintensities . Neither type was related to the WAIS IQs of the 80-year assessment , but both were significantly associated with decline in performance IQ from age 50 to age 80 years ( bivariate correlation coefficients 0. 
    Output:
    
Results The most impaired cognitive domains were executive , attentional and memory retrieval mechanisms .
These cognitive features were frequently associated to White Matter Lesions ( WML ) .
Conclusions WML is an independent factor in cognitive decline .