***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: CONTEXT The herbal product Ginkgo biloba is taken frequently with the intention of improving cognitive health in aging . However , evidence from adequately powered clinical trials is lacking regarding its effect on long-term cognitive functioning . OBJECTIVE To determine whether G. biloba slows the rates of global or domain-specific cognitive decline in older adults . DESIGN , SETTING , AND PARTICIPANTS The Ginkgo Evaluation of Memory ( GEM ) study , a r and omized , double-blind , placebo-controlled clinical trial of 3069 community-dwelling participants aged 72 to 96 years , conducted in 6 academic medical centers in the United States between 2000 and 2008 , with a median follow-up of 6.1 years . INTERVENTION Twice-daily dose of 120-mg extract of G. biloba ( n = 1545 ) or identical-appearing placebo ( n = 1524 ) . MAIN OUTCOME MEASURES Rates of change over time in the Modified Mini-Mental State Examination ( 3MSE ) , in the cognitive subscale of the Alzheimer Disease Assessment Scale ( ADAS-Cog ) , and in neuropsychological domains of memory , attention , visual-spatial construction , language , and executive functions , based on sums of z scores of individual tests . RESULTS Annual rates of decline in z scores did not differ between G. biloba and placebo groups in any domains , including memory ( 0.043 ; 95 % confidence interval [ CI ] , 0.034 - 0.051 vs 0.041 ; 95 % CI , 0.032 - 0.050 ) , attention ( 0.043 ; 95 % CI , 0.037 - 0.050 vs 0.048 ; 95 % CI , 0.041 - 0.054 ) , visuospatial abilities ( 0.107 ; 95 % CI , 0.097 - 0.117 vs 0.118 ; 95 % CI , 0.108 - 0.128 ) , language ( 0.045 ; 95 % CI , 0.037 - 0.054 vs 0.041 ; 95 % CI , 0.033 - 0.048 ) , and executive functions ( 0.092 ; 95 % CI , 0.086 - 0.099 vs 0.089 ; 95 % CI , 0.082 - 0.096 ) . For the 3MSE and ADAS-Cog , rates of change varied by baseline cognitive status ( mild cognitive impairment ) , but there were no differences in rates of change between treatment groups ( for 3MSE , P = .71 ; for ADAS-Cog , P = .97 ) . There was no significant effect modification of treatment on rate of decline by age , sex , race , education , APOE*E4 allele , or baseline mild cognitive impairment ( P > .05 ) . CONCLUSION Compared with placebo , the use of G. biloba , 120 mg twice daily , did not result in less cognitive decline in older adults with normal cognition or with mild cognitive impairment . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00010803 Background Menopausal hormone therapy ( MHT ) reportedly increases the risk of cognitive decline in women over age 65 y. It is unknown whether similar risks exist for recently postmenopausal women , and whether MHT affects mood in younger women . The ancillary Cognitive and Affective Study ( KEEPS-Cog ) of the Kronos Early Estrogen Prevention Study ( KEEPS ) examined the effects of up to 4 y of MHT on cognition and mood in recently postmenopausal women . Methods and Findings KEEPS , a r and omized , double-blinded , placebo-controlled clinical trial , was conducted at nine US academic centers . Of the 727 women enrolled in KEEPS , 693 ( 95.3 % ) participated in the ancillary KEEPS-Cog , with 220 women r and omized to receive 4 y of 0.45 mg/d oral conjugated equine estrogens ( o-CEE ) plus 200 mg/d micronized progesterone ( m-P ) for the first 12 d of each month , 211 women r and omized to receive 50 μg/d transdermal estradiol ( t-E2 ) plus 200 mg/d m-P for the first 12 d of each month , and 262 women r and omized to receive placebo pills and patches . Primary outcomes included the Modified Mini-Mental State examination ; four cognitive factors : verbal learning/memory , auditory attention/working memory , visual attention/executive function , and speeded language /mental flexibility ; and a mood measure , the Profile of Mood States ( POMS )  . MHT effects were analyzed using linear mixed-effects ( LME ) models , which make full use of all available data from each participant , including those with missing data . Data from those with and without full data were compared to assess for potential biases result ing from missing observations . For statistically significant results , we calculated effect sizes ( ESs ) to evaluate the magnitude of changes . On average , participants were 52.6 y old , and 1.4 y past their last menstrual period . By month 48 , 169 ( 24.4 % ) and 158 ( 22.8 % ) of the 693 women who consented for ancillary KEEPS-Cog were lost to follow-up for cognitive assessment ( 3MS and cognitive factors ) and mood evaluations ( POMS ) , respectively . However , because LME models make full use all available data , including data from women with missing data , 95.5 % of participants were included in the final analysis ( n = 662 in cognitive analyses , and n = 661 in mood analyses ) . To be included in analyses , women must have provided baseline data , and data from at least one post-baseline visit . The mean length of follow-up was 2.85 y ( st and ard deviation [ SD ] = 0.49 ) for cognitive outcomes and 2.76 ( SD = 0.57 ) for mood outcomes . No treatment-related benefits were found on cognitive outcomes . For mood , model estimates indicated that women treated with o-CEE showed improvements in depression and anxiety symptoms over the 48 mo of treatment , compared to women on placebo . The model estimate for the depression subscale was −5.36 × 10−2 ( 95 % CI , −8.27 × 10−2 to −2.44 × 10−2 ; ES = 0.49 , p < 0.001 ) and for the anxiety subscale was −3.01 × 10−2 ( 95 % CI , −5.09 × 10−2 to −9.34 × 10−3 ; ES = 0.26 , p < 0.001 ) . Mood outcomes for women r and omized to t-E2 were similar to those for women on placebo . Importantly , the KEEPS-Cog results can not be extrapolated to treatment longer than 4 y. Conclusions The KEEPS-Cog findings suggest that for recently postmenopausal women , MHT did not alter cognition as hypothesized . However , beneficial mood effects with small to medium ESs were noted with 4 y of o-CEE , but not with 4 y of t-E2 . The generalizability of these findings is limited to recently postmenopausal women with low cardiovascular risk profiles . Trial Registration Clinical Trials.gov NCT00154180 and Physical exercise has been shown to increase brain volume and improve cognition in r and omized trials of non-demented elderly . Although greater social engagement was found to reduce dementia risk in observational studies , r and omized trials of social interventions have not been reported . A representative sample of 120 elderly from Shanghai , China was r and omized to four groups ( Tai Chi , Walking , Social Interaction , No Intervention ) for 40 weeks . Two MRIs were obtained , one before the intervention period , the other after . A neuropsychological battery was administered at baseline , 20 weeks , and 40 weeks . Comparison of changes in brain volumes in intervention groups with the No Intervention group were assessed by t-tests . Time-intervention group interactions for neuropsychological measures were evaluated with repeated- measures mixed models . Compared to the No Intervention group , significant increases in brain volume were seen in the Tai Chi and Social Intervention groups ( p < 0.05 ) . Improvements also were observed in several neuropsychological measures in the Tai Chi group , including the Mattis Dementia Rating Scale score ( p = 0.004 ) , the Trailmaking Test A ( p = 0.002 ) and B ( p = 0.0002 ) , the Auditory Verbal Learning Test ( p = 0.009 ) , and verbal fluency for animals ( p = 0.01 ) . The Social Interaction group showed improvement on some , but fewer neuropsychological indices . No differences were observed between the Walking and No Intervention groups . The findings differ from previous clinical trials in showing increases in brain volume and improvements in cognition with a largely non-aerobic exercise ( Tai Chi ) . In addition , intellectual stimulation through social interaction was associated with increases in brain volume as well as with some cognitive improvements Is it possible to prevent atrophy of key brain regions related to cognitive decline and Alzheimer ’s disease ( AD ) ? One approach is to modify nongenetic risk factors , for instance by lowering elevated plasma homocysteine using B vitamins . In an initial , r and omized controlled study on elderly subjects with increased dementia risk ( mild cognitive impairment according to 2004 Petersen criteria ) , we showed that high-dose B-vitamin treatment ( folic acid 0.8 mg , vitamin B6 20 mg , vitamin B12 0.5 mg ) slowed shrinkage of the whole brain volume over 2 y. Here , we go further by demonstrating that B-vitamin treatment reduces , by as much as seven fold , the cerebral atrophy in those gray matter ( GM ) regions specifically vulnerable to the AD process , including the medial temporal lobe . In the placebo group , higher homocysteine levels at baseline are associated with faster GM atrophy , but this deleterious effect is largely prevented by B-vitamin treatment . We additionally show that the beneficial effect of B vitamins is confined to participants with high homocysteine ( above the median , 11 µmol/L ) and that , in these participants , a causal Bayesian network analysis indicates the following chain of events : B vitamins lower homocysteine , which directly leads to a decrease in GM atrophy , thereby slowing cognitive decline . Our results show that B-vitamin supplementation can slow the atrophy of specific brain regions that are a key component of the AD process and that are associated with cognitive decline . Further B-vitamin supplementation trials focusing on elderly subjets with high homocysteine levels are warranted to see if progression to dementia can be prevented IMPORTANCE Oxidative stress and vascular impairment are believed to partly mediate age-related cognitive decline , a strong risk factor for development of dementia . Epidemiologic studies suggest that a Mediterranean diet , an antioxidant-rich cardioprotective dietary pattern , delays cognitive decline , but clinical trial evidence is lacking . OBJECTIVE To investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet . DESIGN , SETTING , AND PARTICIPANTS Parallel-group r and omized clinical trial of 447 cognitively healthy volunteers from Barcelona , Spain ( 233 women [ 52.1 % ] ; mean age , 66.9 years ) , at high cardiovascular risk were enrolled into the Prevención con Dieta Mediterránea nutrition intervention trial from October 1 , 2003 , through December 31 , 2009 . All patients underwent neuropsychological assessment at inclusion and were offered retesting at the end of the study . INTERVENTIONS Participants were r and omly assigned to a Mediterranean diet supplemented with extravirgin olive oil ( 1 L/wk ) , a Mediterranean diet supplemented with mixed nuts ( 30 g/d ) , or a control diet ( advice to reduce dietary fat ) . MAIN OUTCOMES AND MEASURES Rates of cognitive change over time based on a neuropsychological test battery : Mini-Mental State Examination , Rey Auditory Verbal Learning Test ( RAVLT ) , Animals Semantic Fluency , Digit Span subtest from the Wechsler Adult Intelligence Scale , Verbal Paired Associates from the Wechsler Memory Scale , and the Color Trail Test . We used mean z scores of change in each test to construct 3 cognitive composites : memory , frontal ( attention and executive function ) , and global . RESULTS Follow-up cognitive tests were available in 334 participants after intervention ( median , 4.1 years ) . In multivariate analyses adjusted for confounders , participants allocated to a Mediterranean diet plus olive oil scored better on the RAVLT ( P = .049 ) and Color Trail Test part 2 ( P = .04 ) compared with controls ; no between-group differences were observed for the other cognitive tests . Similarly adjusted cognitive composites ( mean z scores with 95 % CIs ) for changes above baseline of the memory composite were 0.04 ( -0.09 to  
    Output:
    
Results suggested that the Mediterranean diet supplemented by olive oil and tai chi exercise may improve global cognition , and the Mediterranean diet plus olive oil and soy isoflavone supplements may improve memory .
Cognitive training may have cognitive benefit as well .
We conclude that some interventions that can be self-initiated by healthy midlife and older adults may ameliorate cognitive aging