Each study has a usefulness score out of 100 (rubric version 4.0). Tap a score to see what makes it up.
Highest usefulness score first. Studies without a score come last.
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Trauma exposure itself in the absence of posttraumatic stress disorder (PTSD) may be associated with hippocampal volume deficits.
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Sixty-six studies met inclusion criteria for the relationship between physical activity and functional independence, and 34 were included with a cognitive function outcome.
Why it matters
This systematic review found that a relatively high level of physical activity was related to better cognitive function and reduced risk of developing dementia, although results of exercise interventions on cognitive function indices were mixed. It suggests moderate to higher levels of activity may be effective, with possibly a threshold of at least moderate activity for significant outcomes.
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57/100
Evidence is insufficient to support the use of pharmaceutical agents or dietary supplements to prevent cognitive decline or Alzheimer’s disease.
Why it matters
This National Institutes of Health consensus statement concluded that evidence is insufficient to support using pharmaceutical agents or dietary supplements to prevent cognitive decline or Alzheimer's disease. It calls for large-scale population studies and randomized controlled trials and reports no proven prevention.
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There is increasing evidence to suggest that physical activity has a protective effect on brain functioning in older people.
Why it matters
This review notes that no randomized controlled trial has shown that regular physical activity prevents dementia, though some recent trials suggest aerobic exercise may improve cognitive functioning in older people. The evidence for a protective effect on brain aging is accumulating from basic research, but prevention of Alzheimer's disease through exercise remains unproven.
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Preliminary findings suggest that some factors may identify those at risk for persistent delirium; however, more research is needed.
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This is the first study to continuously monitor mobility levels early during a hospital stay.
Why it matters
This observational study found that hospitalised older patients spent about 83% of their measured hospital stay lying in bed, despite most being able to walk independently before admission. It is about low mobility during hospitalisation and does not test any treatment, cure, or prevention for Alzheimer's disease.
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The late-life dementia risk index accurately stratified older adults into those with low, moderate, and high risk of developing dementia.
Why it matters
In 3,375 dementia-free older adults (mean age 76) from the Cardiovascular Health Cognition Study, researchers built a points-based index from factors such as age, cognitive test scores, brain MRI findings, carotid ultrasound and physical performance. Over six years, 4% of low scorers, 23% of moderate scorers and 56% of high scorers developed dementia (c statistic 0.81). It predicts risk; it does not show that changing any of these factors prevents dementia.
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57/100
Further exploration of relationships between oral health and cognition is warranted.
Why it matters
In 2,355 older adults, a blood marker of periodontitis was linked to poorer delayed verbal recall and impaired subtraction. This cross-sectional study shows an association between gum disease and cognitive test performance but cannot show cause or a way to prevent dementia.
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Recent studies have also shown that cannabinoids may have more specific effects in interrupting the pathological process in Alzheimer's disease.
Why it matters
This systematic review searched for trials of cannabinoids to treat dementia but found only one study that met its criteria, and that study's data could not be extracted for analysis. With insufficient quantitative data to validate the results, the review offers no reliable evidence on whether cannabinoids help people with dementia.
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Resource accounts of behavioral aging postulate that age-associated impairments within and across intellectual and sensory domains reflect, in part, a common set of senescent alterations in the neurochemistry and neuroanatomy of the aging brain.
Why it matters
This longitudinal study found that individual differences in rates of cognitive decline were highly correlated, with a single factor accounting for 60% of the variance in cognitive change. Contrary to expectations, correlations between cognitive and sensory declines were only moderate, so sensory decline is not a strong stand-in for cognitive decline.
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In recent years, accumulating evidence has suggested that vascular risk factors contribute to Alzheimer disease (AD).
Why it matters
This article discusses accumulating evidence that vascular risk factors contribute to Alzheimer disease, describing a spectrum from pure vascular dementia to pure Alzheimer's disease with most patients having contributions from both. It discusses designing a therapeutic trial to control vascular risk factors for dementia prevention.
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Although all studies were cross-sectional, our results suggest that hippocampal volume reductions generally occur after disease onset in patients with MDD.
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Subjective cognitive failures (SCF) are associated with lower hippocampal volume, even in subjects without objective cognitive impairment and independent of white matter lesions.
Why it matters
In elderly people with white matter lesions, those reporting subjective cognitive and memory failures had lower hippocampal volumes, even when objective cognitive performance was good. This links subjective complaints to hippocampal volume independent of white matter lesions, but it does not test any treatment.
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57/100
Older age and vascular disease, particularly among African Americans, are associated with increased brain atrophy and WMH burden.
Why it matters
In 769 dementia-free older adults from northern Manhattan, MRI showed that older age and a self-reported history of vascular disease went with smaller brains and more white matter damage (WMH), and the vascular link was strongest among African Americans. African American and Hispanic participants had larger relative brain volumes but more WMH than white participants, and the authors say the WMH gap "seem[s] to be partially attributable to differences in vascular disease." This is a one-time snapshot that shows associations, not causes, and it did not measure memory or test any treatment.
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Cognitive and mood disorders were common in elderly hip fracture patients and were associated with greater risk of poor outcomes, both independently and in combination.
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57/100
No definitive conclusions about the superiority of any of the tested interventions can be made.
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57/100
Men, but not women, with unrecognized myocardial infarction (MI) have an increased risk of cardiac events and stroke compared with those without MI or with recognized MI.
Why it matters
This study examined whether unrecognized myocardial infarction is a risk factor for dementia and cerebral small vessel disease in two population-based cohorts. It looks at a possible risk factor but does not test any treatment, cure, or prevention.
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Thirty years of brain imaging research has converged to define the brain's default network-a novel and only recently appreciated brain system that participates in internal modes of cognition.
Why it matters
Reviews brain imaging research on the default network, a brain system most active when people are not focused on the outside world, such as when recalling memories or envisioning the future. The authors close by discussing its relevance to mental disorders including autism, schizophrenia, and Alzheimer's disease.
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Several studies indicate that stroke increases the risk of dementia.
Why it matters
This study explored whether stroke was related to a higher risk of subsequent dementia while accounting for prestroke cognitive function. It does not show that preventing stroke prevents dementia, and the findings are from an observational cohort.
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57/100
We conclude that conversion rate from MCI to DSM-IIIR dementia was 21.9% over a period of 3 years.
Why it matters
Among 105 people with mild cognitive impairment followed for up to three years, 21.9% converted to dementia, and depressive symptoms and impairment beyond memory were predictors of progression. This is an observational follow-up study and does not show that any treatment, cure, or prevention works.
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Three randomized controlled trials (RCTs) and 6 single-case designs (SCDs; N of 1 trials) met inclusion criteria.
Why it matters
This review found limited evidence from a small number of studies on nonpharmacological interventions for neuropsychiatric symptoms in dementia. It does not test any treatment, cure, or prevention for Alzheimer's disease itself.
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Thirty-two percent of residents had DNR directives, whereas less than 2% had DNH directives.
Why it matters
This study found that ethnic minority residents in skilled nursing facilities were less likely to have do-not-resuscitate or do-not-hospitalize directives than Caucasian residents. It addresses end-of-life care preferences, not the treatment, cure, or prevention of Alzheimer's disease.
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Obesity at midlife is associated with an increased risk of dementia and AD later in life.
Why it matters
Midlife obesity, high total cholesterol, and high systolic blood pressure were each linked to about double the risk of dementia, and having all three together raised the risk even more. This indicates that managing these vascular risk factors in midlife might help lower the chance of developing dementia later, though the study cannot prove that treating them prevents dementia.
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57/100
During follow-up, 13 healthy patients converted to MCI or Alzheimer disease (AD), whereas 39 MCI subjects converted to AD.
Why it matters
In healthy elderly and amnestic MCI subjects, higher brain atrophy rates measured from serial MRI 1 to 2 years before baseline were associated with increased risk of later conversion to a more impaired state. Combining a baseline hippocampal volume measure with an atrophy rate measure improved prediction.
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Cognitive functions and self-reported drinking habits were assessed at 2-year intervals over an average of 7 years of follow-up.
Why it matters
This longitudinal community study followed elderly people free of dementia at baseline, assessing drinking habits and cognition every 2 years over about 7 years. The provided text does not report the results, so it is unknown whether alcohol consumption was associated with cognitive decline.