Longitudinal follow-up of individual white matter hyperintensities in a large cohort of elderly

[Echo Train Length (ETL) of Fluid-attenuated Inversion Recovery (FLAIR) and Extraction Volume of White Matter Hyperintensity Volume in Automated White Matter Signal Analysis]

PURPOSE

To investigate whether the volume of white matter hyperintensity (WMH) extracted from FLAIR images changes when the imaging parameters of the original images are changed.

METHODS

Seven healthy volunteers were imaged by changing the imaging parameter ETL of FLAIR images, and WMHs were extracted and their volumes were calculated by the automatic extraction software. The results were statistically analyzed to examine the relationship (Experiment 1). Simulated images with different SNRs were created by adding white noise to four examples of healthy volunteer images. The SNR of the simulated images simulated the SNR of the measured images of different ETLs. The WMH was extracted from the simulated images and its volume was calculated using the automatic extraction software (Experiment 2).

RESULTS

Experiment 1 showed that there was no significant difference between FLAIR imaging parameters and WMH volume in automatic white matter signal analysis, except for some conditions. Experiment 2 showed that as the SNR of the original image decreased, the volume of high white matter signal extracted decreased.

CONCLUSION

In automatic white matter signal analysis, WMH was shown to be small when the ETL of the FLAIR sequence was larger than normal and/or the SNR of the image was low.

Distinct Hippocampal Subfields Atrophy in Older People With Vascular Brain Injuries

BACKGROUND AND PURPOSE

Many neurological or psychiatric diseases affect the hippocampus during aging. The study of hippocampal regional vulnerability may provide important insights into the pathophysiological mechanisms underlying these processes; however, little is known about the specific impact of vascular brain damage on hippocampal subfields atrophy.

METHODS

To analyze the effect of vascular injuries independently of other pathological conditions, we studied a population-based cohort of nondemented older adults, after the exclusion of people who were diagnosed with neurodegenerative diseases during the 14-year clinical follow-up period. Using an automated segmentation pipeline, 1.5T-magnetic resonance imaging at inclusion and 4 years later were assessed to measure both white matter hyperintensities and hippocampal subfields volume. Annualized rates of white matter hyperintensity progression and annualized rates of hippocampal subfields atrophy were then estimated in each participant.

RESULTS

We included 249 participants in our analyses (58% women, mean age 71.8, median Mini-Mental State Evaluation 29). The volume of the subiculum at baseline was the only hippocampal subfield volume associated with total, deep/subcortical, and periventricular white matter hyperintensity volumes, independently of demographic variables and vascular risk factors (β=-0.17, P=0.011; β=-0.25, P=0.020 and β=-0.14, P=0.029, respectively). In longitudinal measures, the annualized rate of subiculum atrophy was significantly higher in people with the highest rate of deep/subcortical white matter hyperintensity progression, independently of confounding factors (β=-0.32, P=0.014).

CONCLUSIONS

These cross-sectional and longitudinal findings highlight the links between vascular brain injuries and a differential vulnerability of the subiculum within the hippocampal loop, unbiased of the effect of neurodegenerative diseases, and particularly when vascular injuries affect deep/subcortical structures.

Interactions Between Age, Sex, Menopause, and Brain Structure at Midlife: A UK Biobank Study

OBJECTIVES

Age and female sex are risk factors for dementia, and menopause is associated with cognitive dysfunction. Previous work largely considered the effects of sex and menopause as being independent of age. We studied whether age interacts with sex or menopause in explaining imaging biomarkers of dementia during midlife.

METHODS

In this cross-sectional study of UK Biobank participants with brain magnetic resonance imaging (MRI), we explored the interaction of age with sex or menopausal status in explaining total brain volume (TBV), gray matter volume (GMV), white matter volume (WMV), white matter hyperintensity volume (WMHV), regional cortical volume , and subcortical volume.

RESULTS

Data were available for 1827 postmenopausal women, 230 pre/perimenopausal women and 2165 men (median age 63.3 years). There was a significant interaction between age and sex (P = .024) for TBV, where the inverse association age with TBV was steeper in women (β = -5.35 mL/year) than in men (β = -4.77 mL/year). Similar age-sex interactions were also observed for GMV and WMV. In women, there was a significant interaction between age and menopausal status (P = .007) where the inverse association of age with TBV was steeper in postmenopausal (β = -5.89 mL/year) than in pre/perimenopausal women (β = -1.61 mL/year). Similar age-menopause interactions were found in predicting lower GMV and higher WMHV. Differences in the direction of these age-sex and age-menopause interactions were found for regional cortical and subcortical brain volumes.

CONCLUSION

Sex and menopause both interact with age during midlife in explaining MRI biomarkers of dementia. Further work is required to understand the mechanisms driving these interactions to develop strategies for delaying dementia.

Cerebral white matter free water: A sensitive biomarker of cognition and function

OBJECTIVE

To determine whether free water (FW) content, initially developed to correct metrics derived from diffusion tensor imaging and recently found to be strongly associated with vascular risk factors, may constitute a sensitive biomarker of white matter (WM) microstructural differences associated with cognitive performance but remains unknown.

METHODS

Five hundred thirty-six cognitively diverse individuals, aged 77 ± 8 years, received yearly comprehensive clinical evaluations and a baseline MRI examination of whom 224 underwent follow-up MRI. WM microstructural measures, including FW, fractional anisotropy, and mean diffusivity corrected for FW and WM hyperintensity burden were computed within WM voxels of each individual. Baseline and change in MRI metrics were then used as independent variables to explain baseline and change in episodic memory (EM), executive function (EF), and Clinical Dementia Rating (CDR) scores using linear, logistic, and Cox proportional-hazards regressions.

RESULTS

Higher baseline FW and WM hyperintensity were associated with lower baseline EM and EF, higher baseline CDR, accelerated EF and EM decline, and higher probability to transition to a more severe CDR stage (p values <0.01). Annual change in FW was also found to be associated with concomitant change in cognitive and functional performance (p values <0.01).

CONCLUSIONS

This study finds cross-sectional and longitudinal associations between FW content and trajectory of cognitive and functional performance in a large sample of cognitively diverse individuals. It supports the need to investigate the pathophysiologic process that manifests increased FW, potentially leading to more severe WM territory injury and promoting cognitive and functional decline.

Randomized Trial of Marine n-3 Polyunsaturated Fatty Acids for the Prevention of Cerebral Small Vessel Disease and Inflammation in Aging (PUFA Trial): Rationale, Design and Baseline Results

Vascular risk factors for age-related cognitive decline are significant, and their management may ultimately prove the most successful strategy for reducing risk and sustaining cognitive health. This randomized, double-blinded, placebo-controlled trial with parallel group allocation to either marine n-3 polyunsaturated fatty acids (n-3 PUFA) or soybean oil placebo assesses the effects on the total volume of accumulation in cerebral white matter hyperintensities (WMH), a potentially modifiable neurovascular component of age-related cognitive decline. Total WMH accumulation over 3 years is the primary endpoint. The safety and efficacy of n-3 PUFA is evaluated in older adults with significant WMH and suboptimum plasma n-3 PUFA as inclusion criteria. One hundred and two non-demented older adults were enrolled with a mean age of 81.1 (±4.4) years, WMH of 19.4 (±16.1) cm³, and a plasma n-3 PUFA of 86.64 (±29.21) µg/mL. 61% were female, 28% were apolipoprotein E epsilon 4 carriers, and the mean mini-mental state exam (MMSE) was 27.9 (±1.7). This trial provides an initial evaluation of n-3 PUFA effects on WMH, a reproducible and valid risk biomarker for cognitive decline, as well as on inflammatory biomarkers thought to play a role in WMH accumulation. We present the baseline results and operational experience of enriching a study population on advanced age, blood n-3 PUFA, and magnetic resonance imaging (MRI) derived WMH with biomarker outcomes (WMH, inflammation markers) in a dementia prevention paradigm.

Characterization of White Matter Hyperintensities in Large-Scale MRI-Studies

Background: White matter hyperintensities of presumed vascular origin (WMH) are a common finding in elderly people and a growing social malady in the aging western societies. As a manifestation of cerebral small vessel disease, WMH are considered to be a vascular contributor to various sequelae such as cognitive decline, dementia, depression, stroke as well as gait and balance problems. While pathophysiology and therapeutical options remain unclear, large-scale studies have improved the understanding of WMH, particularly by quantitative assessment of WMH. In this review, we aimed to provide an overview of the characteristics, research subjects and segmentation techniques of these studies.

Methods: We performed a systematic review according to the PRISMA statement. One thousand one hundred and ninety-six potentially relevant articles were identified via PubMed search. Six further articles classified as relevant were added manually. After applying a catalog of exclusion criteria, remaining articles were read full-text and the following information was extracted into a standardized form: year of publication, sample size, mean age of subjects in the study, the cohort included, and segmentation details like the definition of WMH, the segmentation method, reference to methods papers as well as validation measurements.

Results: Our search resulted in the inclusion and full-text review of 137 articles. One hundred and thirty-four of them belonged to 37 prospective cohort studies. Median sample size was 1,030 with no increase over the covered years. Eighty studies investigated in the association of WMH and risk factors. Most of them focussed on arterial hypertension, diabetes mellitus type II and Apo E genotype and inflammatory markers. Sixty-three studies analyzed the association of WMH and secondary conditions like cognitive decline, mood disorder and brain atrophy. Studies applied various methods based on manual (3), semi-automated (57), and automated segmentation techniques (75). Only 18% of the articles referred to an explicit definition of WMH.

Discussion: The review yielded a large number of studies engaged in WMH research. A remarkable variety of segmentation techniques was applied, and only a minority referred to a clear definition of WMH. Most addressed topics were risk factors and secondary clinical conditions. In conclusion, WMH research is a vivid field with a need for further standardization regarding definitions and used methods.

White Matter Lesions are Associated with Specific Depressive Symptom Trajectories among Incident Depression and Dementia Populations: Three-City Dijon MRI Study

OBJECTIVE

Evidence is mixed as to whether periventricular or deep white matter hyperintensities (WMHs) increase the risk for depressive symptoms, partly because of heterogeneity in depression measurement, short follow-up, and confounding by prodromal dementia. The study objective was to evaluate WMH volume in relation to discrete depressive symptoms over 10 years, stratifying by incident depression and dementia.

METHODS

In this prospective longitudinal cohort study of a representative population sample from Dijon, France, 1,440 participants aged 65-80 years (median age: 72 years; 59.5% women) without depression, dementia, or stroke at baseline were studied. Baseline T2-weighted images were obtained in a 1.5-T scanner to quantify WMHs (log cm³). Clinic visits were performed up to five times in a 10-year period to assess incident neurologic diseases and comorbidities. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale and converted to factor z scores, representing somatic symptoms, depressed affect, low positive affect, and interpersonal problems.

RESULTS

Periventricular WMH volume was uniquely associated with low positive affect among incident depression cases (β = 0.15; 95% confidence interval [CI]: 0.02-0.29; p = 0.026). Deep WMH volume was uniquely associated with depressed affect among incident dementia cases (β = 0.36; 95% CI: 0.05-0.68; p = 0.025). WMH volume (periventricular, deep, and total) was associated with interpersonal problems among persons who developed dementia with depression.

CONCLUSION

The findings highlight that regional WMH volumes and specific depressive symptoms have clinical and prognostic relevance to help differentiate between persons at risk for depression and dementia.

Nonlinear temporal dynamics of cerebral small vessel disease: The RUN DMC study

OBJECTIVE

To investigate the temporal dynamics of cerebral small vessel disease (SVD) by 3 consecutive assessments over a period of 9 years, distinguishing progression from regression.

METHODS

Changes in SVD markers of 276 participants of the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Imaging Cohort (RUN DMC) cohort were assessed at 3 time points over 9 years. We assessed white matter hyperintensities (WMH) volume by semiautomatic segmentation and rated lacunes and microbleeds manually. We categorized baseline WMH severity as mild, moderate, or severe according to the modified Fazekas scale. We performed mixed-effects regression analysis including a quadratic term for increasing age.

RESULTS

Mean WMH progression over 9 years was 4.7 mL (0.54 mL/y; interquartile range 0.95-5.5 mL), 20.3% of patients had incident lacunes (2.3%/y), and 18.9% had incident microbleeds (2.2%/y). WMH volume declined in 9.4% of the participants during the first follow-up interval, but only for 1 participant (0.4%) throughout the whole follow-up. Lacunes disappeared in 3.6% and microbleeds in 5.7% of the participants. WMH progression accelerated over time: including a quadratic term for increasing age during follow-up significantly improved the model (p < 0.001). SVD progression was predominantly seen in participants with moderate to severe WMH at baseline compared to those with mild WMH (odds ratio [OR] 35.5, 95% confidence interval [CI] 15.8-80.0, p < 0.001 for WMH progression; OR 5.7, 95% CI 2.8-11.2, p < 0.001 for incident lacunes; and OR 2.9, 95% CI 1.4-5.9, p = 0.003 for incident microbleeds).

CONCLUSIONS

SVD progression is nonlinear, accelerating over time, and a highly dynamic process, with progression interrupted by reduction in some, in a population that on average shows progression.

Disease progression and regression in sporadic small vessel disease-insights from neuroimaging

Cerebral small vessel disease (SVD) is considered the most important vascular contributor to the development of dementia. Comprehensive characterization of the time course of disease progression will result in better understanding of aetiology and clinical consequences of SVD. SVD progression has been studied extensively over the years, usually describing change in SVD markers over time using neuroimaging at two time points. As a consequence, SVD is usually seen as a rather linear, continuously progressive process. This assumption of continuous progression of SVD markers was recently challenged by several studies that showed regression of SVD markers. Here, we provide a review on disease progression in sporadic SVD, thereby taking into account both progression and regression of SVD markers with emphasis on white matter hyperintensities (WMH), lacunes and microbleeds. We will elaborate on temporal dynamics of SVD progression and discuss the view of SVD progression as a dynamic process, rather than the traditional view of SVD as a continuous progressive process, that might better fit evidence from longitudinal neuroimaging studies. We will discuss possible mechanisms and clinical implications of a dynamic time course of SVD, with both progression and regression of SVD markers.

Collagenosis of the Deep Medullary Veins: An Underrecognized Pathologic Correlate of White Matter Hyperintensities and Periventricular Infarction?

White matter hyperintensities (WMH) are prevalent. Although arteriolar disease has been implicated in their pathogenesis, venous pathology warrants consideration. We investigated relationships of WMH with histologic venous, arteriolar and white matter abnormalities and correlated findings with premortem neuroimaging. Three regions of periventricular white matter were sampled from archived autopsy brains of 24 pathologically confirmed Alzheimer disease (AD) and 18 age-matched nonAD patients. Using trichrome staining, venous collagenosis (VC) of periventricular veins (<150 µm in diameter) was scored for severity of wall thickening and occlusion; percent stenosis by collagenosis of large caliber (>200 µm) veins (laVS) was measured. Correlations were made between WMH in premortem neuroimaging and vascular and white matter pathology. We found greater VC (U(114) = 2092.5, p = 0.005 and U(114) = 2121.5, p = 0.002 for small and medium caliber veins, respectively) and greater laVS (t(110) = 3.46, p = 0.001) in patients with higher WMH scores; WMH scores correlated with VC (rs(114) = 0.27, p = 0.004) and laVS (rs(110) = 0.38, p < 0.001). By multiple linear regression analysis, the strongest predictor of WMH score was laVS (β = 0.338, p < 0.0001). VC was frequent in patients with periventricular infarcts identified on imaging. We conclude that periventricular VC is associated with WMH in both AD and nonAD patients and the potential roles of VC in WMH pathogenesis merit further study.

Differential Effect of White-Matter Lesions and Covert Brain Infarcts on the Risk of Ischemic Stroke and Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

We examined the association of white-matter hyperintensity (WMH) volume and covert brain infarcts, which are the 2 major magnetic resonance imaging markers of covert cerebrovascular disease in older adults, with long-term risk of ischemic stroke and intracerebral hemorrhage (ICH) in the general population.

METHODS

Participants were 1731 individuals aged ≥65 years from the Three-City Dijon study. We studied the association of WMH volume and brain infarct, with incident ischemic stroke overall, and by subtype, and with incident ICH.

RESULTS

High total, periventricular, and deep WMHs were associated with incident ICH. Extensive periventricular WMH volume was associated with increased risk of ischemic stroke (hazard ratio, 1.94; 95% confidence interval, 1.12-3.35), particularly cardioembolic stroke. Covert brain infarcts were associated with incident ICH but not with incident ischemic stroke or its subtypes.

CONCLUSIONS

Although of ischemic nature, both WMH volume and covert brain infarcts portend a major risk of ICH. If confirmed in independent studies, these findings could have important implications for the clinical management of covert vascular brain lesions.

Age-associated differences on structural brain MRI in nondemented individuals from 71 to 103 years

Successful brain aging in the oldest old (≥90 years) is underexplored. This study examined cross-sectional brain morphological differences from 8th to 11th decades of life in nondemented individuals by high-resolution magnetic resonance imaging. Two hundred seventy-seven nondemented community-dwelling participants (71-103 years) from Sydney Memory and Ageing Study and Sydney Centenarian Study comprised the sample, including a subsample of 160 cognitively high-functioning elders. Relationships between age and magnetic resonance imaging-derived measurements were studied using general linear models; and structural profiles of the ≥90 years were delineated. In full sample and the subsample, significant linear negative relationship of gray matter with age was found, with the greatest age effects in the medial temporal lobe and parietal and occipital cortices. This pattern was further confirmed by comparing directly the ≥90 years to the 71-89 years groups. Significant quadratic age effects on total white matter and white matter hyperintensities were observed. Our study demonstrated heterogeneous differences across brain regions between the oldest old and young old, with an emphasis on hippocampus, temporoposterior cortex, and white matter hyperintensities.

Longitudinal change of small-vessel disease-related brain abnormalities

Knowledge about the longitudinal change of cerebral small-vessel disease–related magnetic resonance imaging abnormalities increases our pathophysiologic understanding of cerebral microangiopathy. The change of specific lesion types may also serve as secondary surrogate endpoint in clinical trials. A surrogate endpoint needs to progress fast enough to allow monitoring of treatment effects within a reasonable time period, and change of the brain abnormality needs to be correlated with clinical change. Confluent white matter lesions show fast progression and correlations with cognitive decline. Thus, the change of confluent white matter lesions may be used as a surrogate marker in proof-of-concept trials with small patient numbers needed to show treatment effects on lesion progression. Nonetheless if the expected change in cognitive performance resulting from treatment effects on lesion progression is used as outcome, the sample size needed to show small to moderate treatment effects becomes very large. Lacunes may also fulfill the prerequisites of a surrogate marker, but in the general population the incidence of lacunes over short observational periods is small. For other small-vessel disease–related brain abnormalities including microbleeds and microstructural changes in normal-appearing white matter longitudinal change and correlations with clinical decline is not yet fully determined.

Usefulness of data from magnetic resonance imaging to improve prediction of dementia: population based cohort study

OBJECTIVE

To determine whether the addition of data derived from magnetic resonance imaging (MRI) of the brain to a model incorporating conventional risk variables improves prediction of dementia over 10 years of follow-up.

DESIGN

Population based cohort study of individuals aged ≥ 65.

SETTING

The Dijon magnetic resonance imaging study cohort from the Three-City Study, France.

PARTICIPANTS

1721 people without dementia who underwent an MRI scan at baseline and with known dementia status over 10 years' follow-up.

MAIN OUTCOME MEASURE

Incident dementia (all cause and Alzheimer's disease).

RESULTS

During 10 years of follow-up, there were 119 confirmed cases of dementia, 84 of which were Alzheimer's disease. The conventional risk model incorporated age, sex, education, cognition, physical function, lifestyle (smoking, alcohol use), health (cardiovascular disease, diabetes, systolic blood pressure), and the apolipoprotein genotype (C statistic for discrimination performance was 0.77, 95% confidence interval 0.71 to 0.82). No significant differences were observed in the discrimination performance of the conventional risk model compared with models incorporating data from MRI including white matter lesion volume (C statistic 0.77, 95% confidence interval 0.72 to 0.82; P=0.48 for difference of C statistics), brain volume (0.77, 0.72 to 0.82; P=0.60), hippocampal volume (0.79, 0.74 to 0.84; P=0.07), or all three variables combined (0.79, 0.75 to 0.84; P=0.05). Inclusion of hippocampal volume or all three MRI variables combined in the conventional model did, however, lead to significant improvement in reclassification measured by using the integrated discrimination improvement index (P=0.03 and P=0.04) and showed increased net benefit in decision curve analysis. Similar results were observed when the outcome was restricted to Alzheimer's disease.

CONCLUSIONS

Data from MRI do not significantly improve discrimination performance in prediction of all cause dementia beyond a model incorporating demographic, cognitive, health, lifestyle, physical function, and genetic data. There were, however, statistical improvements in reclassification, prognostic separation, and some evidence of clinical utility.

Oxidative stress and genetic markers of suboptimal antioxidant defense in the aging brain: a theoretical review

Normal aging involves a gradual breakdown of physiological processes that leads to a decline in cognitive functions and brain integrity, yet the onset and progression of decline are variable among older individuals. While many biological changes may contribute to this degree of variability, oxidative stress is a key mechanism of the aging process that can cause direct damage to cellular architecture within the brain. Oligodendrocytes are at a high risk for oxidative damage due to their role in myelin maintenance and production and limited repair mechanisms, suggesting that white matter may be particularly vulnerable to oxidative activity. Antioxidant defense enzymes within the brain, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferase (GST), are crucial for breaking down the harmful end products of oxidative phosphorylation. Previous studies have revealed that allele variations of polymorphisms that encode these antioxidants are associated with abnormalities in SOD, CAT, GPx, and GST activity in the central nervous system. This review will focus on the role of oxidative stress in the aging brain and the impact of decreased antioxidant defense on brain integrity and cognitive function. Directions for future research investigations of antioxidant defense genes will also be discussed.

Microvascular brain damage with aging and hypertension: pathophysiological consideration and clinical implications

Loss of cognitive function and hypertension are two common conditions in the elderly and both significantly contribute to loss of personal independency. Microvascular brain damage - the result of age-associated alteration in large arteries and the progressive mismatch of their cross-talk with small cerebral arteries - represents a potent risk factor for cognitive decline and for the onset of dementia in older individuals. The present review discusses the complexity of factors linking large artery to microvascular brain disease and to cognitive decline and the evidence for possible clinical markers useful for prevention of this phenomenon. The possibility of dementia prevention by cardiovascular risk factors control has not been demonstrated. In the absence of research clinical trials specifically and primarily designed to demonstrate the antihypertensive treatment efficacy for reducing the risk of dementia, further evidence demonstrating that it is possible to limit the progression of microvascular brain damage is needed.

Default-mode network connectivity and white matter burden in late-life depression

The brain's default-mode network has been the focus of intense research. This study characterizes the default-mode network activity in late-life depression and the correlation of the default-mode network activity changes with the white-matter hyperintensities burden. We hypothesized that elderly depressed subjects would have altered default-mode network activity, which would correlate with the increased white-matter hyperintensities burden. Twelve depressed subjects (mean Hamilton Depression Rating Scale 19.8±4.1, mean age 70.5±4.9) and 12 non-depressed, comparison subjects (mean age 69±6.5) were included. Functional magnetic resonance imaging (fMRI) data were collected while subjects performed a low cognitive load, event-related task. We compared the default-mode network activity in these groups (including depressed subjects pre- and post-antidepressant treatment). We analyzed the resting connectivity patterns of the posterior cingulate cortex. Deconvolution was used to evaluate the correlation of resting-state connectivity scores with the white-matter hyperintensities burden. Compared with non-depressed elderly, depressed subjects pretreatment had decreased connectivity in the subgenual anterior cingulate cortex and increased connectivity in the dorsomedial prefrontal cortex and the orbito-frontal cortex. The abnormal connectivity was significantly correlated with the white-matter hyperintensities burden. Remitted elderly depressed subjects had improved functional connectivity compared to pretreatment, although alterations persisted in the anterior cingulate and the prefrontal cortex when remitted elderly depressed subjects were compared with non-depressed elderly. Our study provides evidence for altered default-mode network connectivity in late-life depression. The correlation between white-matter hyperintensities burden and default-mode network connectivity emphasizes the role of vascular changes in late-life depression etiopathogenesis.

Impact of white matter lesions on physical functioning and fall risk in older people: a systematic review

BACKGROUND AND PURPOSE

White matter lesions (WMLs) are common findings on neuroimaging in older people. This review systematically evaluates the published literature on the associations between WMLs and balance, gait, mobility, and falls in older people.

METHODS

Studies were identified with searches of the MEDLINE databases. Articles reporting associations between WMLs and balance, gait, mobility, and falls in older people in cross-sectional and longitudinal studies were included.

RESULTS

Thirty-one articles reporting data from 19 studies met the inclusion criteria. There were consistent findings from both cross-sectional and longitudinal studies indicating greater WML volumes are associated with impaired balance, slower gait, and reduced mobility. Most studies addressing regional WML distributions have reported that WMHs in the frontal lobe and periventricular regions show the strongest relationships with balance, gait, and mobility impairments. In relation to falls, a threshold effect was apparent in that only those with severe WML volumes were found to be at increased risk of falling.

CONCLUSIONS

The findings of this systematic review indicate that WMLs are common and are significantly associated with impaired balance, gait, mobility, and falls in older people. In many studies, however, impaired mobility and increased fall risk are only evident in people who have the most severe degree of WMLs.

Longitudinal neuroimaging correlates of subjective memory impairment: 4-year prospective community study

BACKGROUND

Complaints about memory are common in older people but their relationship with underlying brain changes is controversial.

AIMS

To investigate the relationship between subjective memory impairment and previous or subsequent changes in white matter lesions and brain volumes.

METHOD

In a community cohort study of 1336 people without dementia, 4-year changes in brain magnetic resonance imaging measures were investigated as correlates of subjective memory impairment at baseline and follow-up.

RESULTS

Subjective memory impairment at baseline was associated with subsequent change in hippocampal volume and at follow-up impairment was associated with previous change in hippocampal, cerebrospinal fluid and grey matter volume and with subcortical white matter lesion increases. All associations with volume changes were U-shaped with significant quadratic terms - associations between least decline and subjective memory impairment were potentially explained by lower baseline hippocampal volumes in the groups with least volume change. Associations between hippocampal volume change and subjective memory impairment at follow-up were independent of cognitive decline and depressive symptoms, they were stronger in participants with the apolipoprotein E (APOE) ε4 allele and in those without baseline subjective memory impairment.

CONCLUSIONS

Complaints of poor memory by older people, particularly when new, may be a realistic subjective appraisal of recent brain changes independent of observed cognitive decline.

Antihypertensive treatment and change in blood pressure are associated with the progression of white matter lesion volumes: the Three-City (3C)-Dijon Magnetic Resonance Imaging Study

BACKGROUND

Blood pressure (BP) is recognized as a major risk factor for white matter lesions (WMLs), but longitudinal data are scarce, and there is insufficient evidence for the benefit of antihypertensive therapy on WML progression. We studied the relationship between BP change and WML volume progression over time in a sample of 1319 elderly individuals who had 2 cerebral magnetic resonance imaging examinations 4 years apart. We also examined the impact of antihypertensive treatment on WML progression.

METHODS AND RESULTS

Subjects were participants from the Three-City (3C)-Dijon Magnetic Resonance Imaging Study, a prospective population-based cohort of elderly ≥ 65 years of age. WML volumes and their progression were estimated with the use of a fully automatic procedure. We performed ANCOVA models first to assess the association between BP change and WML progression and second to estimate the relation between antihypertensive treatment and WML load progression. Baseline and change in BP were significant predictors of higher WML progression over time after controlling for potential confounders. Among subjects with high SBP (≥ 160 mm Hg) at baseline not treated by antihypertensive medication, antihypertensive treatment started within 2 years was related to a smaller increase in WML volume at a 4-year follow-up (0.24 cm³; SE=0.44 cm³) than no hypertensive treatment (1.60 cm³; SE = 0.26 cm³; P = 0.0008) on multivariable modeling.

CONCLUSIONS

Our findings reinforce the hypothesis that hypertension is a strong predictor of WML and that adequate treatment may reduce the course of WML progression. Because WMLs are linked to both dementia and stroke risks, these results could have implications for future preventive trials.

White matter deterioration in 15 months: latent growth curve models in healthy adults

The goal of the study was to examine the differences in trajectories of change in the volume of white matter hyperintensities (WMH) in healthy adults within a relatively short period. We measured volumes of periventricular and deep WMH in frontal, temporal, parietal, and occipital lobes of healthy volunteers (age 49-83) on 3 occasions, approximately 15 months apart. At baseline, 40 participants underwent magnetic resonance imaging (MRI), 37 returned for the first and 30 for the second follow-up. Latent growth curve models estimated the variance and mean change in WMH volume and examined their associations with age, sex, education, and hypertension. In both regions and for both WMH types, the positive association between volume and age was stronger among the middle-aged adults and became weaker in older ages, as a logarithmic function of age. Individual variations were present in initial WMH volume but not in WMH volume progression. Frontal deep WMH volume was greater in hypertensive participants, whereas lower education was associated with greater posterior deep WMH volume. Thus, white matter of healthy middle-aged and older adults undergoes significant regional deterioration in a relatively short period, and is negatively affected by vascular risk and lower educational level.