Systematic Review and Meta-Analyses of Word Production Abilities in Dysfunction of the Basal Ganglia: Stroke, Small Vessel Disease, Parkinson's Disease, and Huntington's Disease

Clinical populations with basal ganglia pathologies may present with language production impairments, which are often described in combination with comprehension measures or attributed to motor, memory, or processing-speed problems. In this systematic review and meta-analysis, we studied word production in four (vascular and non-vascular) pathologies of the basal ganglia: stroke affecting the basal ganglia, small vessel disease, Parkinson's disease, and Huntington's disease. We compared scores of these clinical populations with those of matched cognitively unimpaired adults on four well-established production tasks, namely picture naming, category fluency, letter fluency, and past-tense verb inflection. We conducted a systematic search in PubMed and PsycINFO with terms for basal ganglia structures, basal ganglia disorders and language production tasks. A total of 114 studies were included, containing results for one or more of the tasks of interest. For each pathology and task combination, effect sizes (Hedges' g) were extracted comparing patient versus control groups. For all four populations, performance was consistently worse than that of cognitively unimpaired adults across the four language production tasks (p-values < 0.010). Given that performance in picture naming and verb inflection across all pathologies was quantified in terms of accuracy, our results suggest that production impairments cannot be fully explained by motor or processing-speed deficits. Our review shows that while language production difficulties in these clinical populations are not negligible, more evidence is necessary to determine the exact mechanism that leads to these deficits and whether this mechanism is the same across different pathologies.

Cocaine use is associated with cerebral white matter hyperintensities in HIV disease

BACKGROUND

White matter hyperintensities (WMH), a marker of cerebral small vessel disease and predictor of cognitive decline, are observed at higher rates in persons with HIV (PWH). The use of cocaine, a potent central nervous system stimulant, is disproportionately common in PWH and may contribute to WMH.

METHODS

The sample included of 110 PWH on antiretroviral therapy. Fluid-attenuated inversion recovery (FLAIR) and T1-weighted anatomical MRI scans were collected, along with neuropsychological testing. FLAIR images were processed using the Lesion Segmentation Toolbox. A hierarchical regression model was run to investigate predictors of WMH burden [block 1: demographics; block 2: cerebrovascular disease (CVD) risk; block 3: lesion burden].

RESULTS

The sample was 20% female and 79% African American with a mean age of 45.37. All participants had persistent HIV viral suppression, and the median CD4+ T-cell count was 750. Nearly a third (29%) currently used cocaine regularly, with an average of 23.75 (SD = 20.95) days in the past 90. In the hierarchical linear regression model, cocaine use was a significant predictor of WMH burden (β = .28). WMH burden was significantly correlated with poorer cognitive function (r = -0.27). Finally, higher WMH burden was significantly associated with increased serum concentrations of interferon-γ-inducible protein 10 (IP-10) but lower concentrations of myeloperoxidase (MPO); however, these markers did not differ by COC status.

CONCLUSIONS

WMH burden is associated with poorer cognitive performance in PWH. Cocaine use and CVD risk independently contribute to WMH, and addressing these conditions as part of HIV care may mitigate brain injury underlying neurocognitive impairment.

The impact of subcortical stroke-related aphasia on executive functions and working memory

Aphasia is a common post-stroke disorder characterized by impairments in speaking, listening, reading, and writing. Although cognitive impairments have been well studied in cortical aphasia, deficits associated with subcortical aphasia remain to be elucidated. The current study aimed to assess executive functions (EF) and working memory (WM) in patients with subcortical aphasia, and investigate the relationship between language abilities and cognition deficits. Participants of this research included patients with thalamus lesions (n = 9; mean age = 53.89 years) and healthy individuals (n = 9; mean age = 54.33 years). Assessment materials were the Mini-Mental State Examination (MMSE), Persian Western Aphasia Battery (P-WAB-1), digit span subtest of Adult Wechsler Test (WAIS-R), and Wisconsin Card Sorting Test (WCST). Obtained results revealed significant differences in all components of EF, as well as in WM forward and backward digit spans between patients and healthy individuals. However, investigating the relationship between MMSE and AQ scores and components of EF and WM revealed no significant difference. In conclusion, the findings of the present research indicated defects in cognitive functions, including WM and EF, in patients with subcortical stroke. Accordingly, it is crucial to provide optimal rehabilitation therapies for the improvement of language and cognitive problems upon subcortical aphasia.

Cognitive impairment in sporadic cerebral small vessel disease: A systematic review and meta-analysis

This paper is a proposal for an update on the characterization of cognitive impairments associated with sporadic cerebral small vessel disease (SVD). We pose a series of questions about the nature of SVD-related cognitive impairments and provide answers based on a comprehensive review and meta-analysis of published data from 69 studies. Although SVD is thought primarily to affect executive function and processing speed, we hypothesize that SVD affects all major domains of cognitive ability. We also identify low levels of education as a potentially modifiable risk factor for SVD-related cognitive impairment. Therefore, we propose the use of comprehensive cognitive assessments and the measurement of educational level both in clinics and research settings, and suggest several recommendations for future research.

Diurnal Blood Pressure and Heart Rate Variability in Hypertensive Patients with Cerebral Small Vessel Disease: A Case-Control Study

BACKGROUND

Whether autonomic dysfunction contributes to cerebral small vessel disease (CSVD) remains unclear. This study aimed to explore the relationship between CSVD and blood pressure variability (BPV) and heart rate variability (HRV).

METHODS

This case-control study recruited 50 patients with CSVD and 50 non-CSVD hypertensive age- and gender-matched controls. All participants completed a 24-h ambulatory electrocardiogram recording and ambulatory BP monitoring (ABPM). Differences in HRV and BPV between the two groups were examined. BPV indices assessed by ABPM included mean systolic BP (SBP), mean diastolic BP (DBP), coefficient of variation and weighted standard deviation of SBP and DBP.

RESULTS

CSVD patients had significant higher 24-h mean systolic BP (SBP), 24-h mean diastolic BP (DBP), daytime mean SBP, nocturnal mean SBP, and nocturnal mean DBP (P < .05 for all). CSVD patients had a significant lower nocturnal SBP fall rate compared with controls (median: 1.0 versus 6.2, respectively; P < .001) and were more likely to be non-dippers and reverse dippers. There were no differences in HRV variables between the two groups. Five logistic models were built to explore the correlations between BPV indices and CSVD. BPV indices were separately entered into the logistic regression models, together with hyperlipidemia, ischemic stroke history, current use of anti-hypertensive agents, and serum blood urea nitrogen. In models 1-3, 24-h mean SBP and nocturnal mean SBP and DBP were significantly correlated with CSVD (r² = 0.308-0.340). In model 4, the nocturnal SBP fall rate was negatively correlated with CSVD (odds ratio [OR] = 0.871, 95% confidence interval [CI] = 0.804-0.943; P = .001), with r² = 0.415 fitting the model. In model 5, the pattern of SBP dipping was significantly associated with CSVD, with non-dipper (OR = 8.389, 95%CI = 1.489-47.254; P = .016) and reverse dipper (OR = 27.008, 95%CI = 3.709-196.660; P = .001) having the highest risks of CSVD (r² = 0.413).

CONCLUSIONS

Lower nocturnal SBP fall rate is associated with CSVD. Non-dipper and reverse dipper hypertensive patients have a higher risk of CSVD.

Cognitive Correlates of MRI-defined Cerebral Vascular Injury and Atrophy in Elderly American Indians: The Strong Heart Study

OBJECTIVE

American Indians experience substantial health disparities relative to the US population, including vascular brain aging. Poorer cognitive test performance has been associated with cranial magnetic resonance imaging findings in aging community populations, but no study has investigated these associations in elderly American Indians.

METHODS

We examined 786 American Indians aged 64 years and older from the Cerebrovascular Disease and its Consequences in American Indians study (2010-2013). Cranial magnetic resonance images were scored for cortical and subcortical infarcts, hemorrhages, severity of white matter disease, sulcal widening, ventricle enlargement, and volumetric estimates for white matter hyperintensities (WMHs), hippocampus, and brain. Participants completed demographic, medical history, and neuropsychological assessments including testing for general cognitive functioning, verbal learning and memory, processing speed, phonemic fluency, and executive function.

RESULTS

Processing speed was independently associated with the presence of any infarcts, white matter disease, and hippocampal and brain volumes, independent of socioeconomic, language, education, and clinical factors. Other significant associations included general cognitive functioning with hippocampal volume. Nonsignificant, marginal associations included general cognition with WMH and brain volume; verbal memory with hippocampal volume; verbal fluency and executive function with brain volume; and processing speed with ventricle enlargement.

CONCLUSIONS

Brain-cognition associations found in this study of elderly American Indians are similar to those found in other racial/ethnic populations, with processing speed comprising an especially strong correlate of cerebrovascular disease. These findings may assist future efforts to define opportunities for disease prevention, to conduct research on diagnostic and normative standards, and to guide clinical evaluation of this underserved and overburdened population.

Cardiometabolic Health and Longitudinal Progression of White Matter Hyperintensity: The Mayo Clinic Study of Aging

Background and Purpose- White matter hyperintensity (WMH) burden is associated with stroke and cognitive decline. Risk factors associated with the longitudinal progression of WMH in the general population have not been systematically investigated. To investigate the primary midlife and current cardiometabolic risk factors associated with changes in WMH over time in a population cohort. Methods- This cohort study included participants enrolled in the Mayo Clinic Study of Aging, a longitudinal population-based study in Olmsted County, Minnesota with at least 2 consecutive WMH assessments on fluid-attenuated inversion recovery-magnetic resonance images (n=554, ≥60 years with midlife assessments) with relevant baseline laboratory measures of interest. Linear mixed model regression was used to determine the important components of cardiometabolic risk profile at baseline that were associated with future progression of WMH. These analyses were controlled for age and sex. Sensitivity analyses were conducted using stratification by sex. The main outcome measure was percent change in WMH normalized to total intracranial volume. Three sets of models were constructed to evaluate individual (1) midlife risk factors, (2) current risk factors including the presence of metabolic syndrome and its constituents, and (3) baseline measurements of continuous laboratory measures of cardiometabolic risk. Results- Age was the strongest predictor of progression in WMH (P<0.001). Baseline hypertension (P<0.001), midlife hypertension (P=0.003), and baseline fasting glucose in males (P=0.01) were predictive of WMH change. The presence of metabolic syndrome was not associated with progressive WMH. In sensitivity analyses, associations between hypertension and WMH progression were stronger in females. Baseline serum glucose was associated with increase in WMH but was not significant in females in the stratified analysis. Other continuous laboratory measures of vascular risk were not associated with progressive WMH. Conclusions- Midlife and current hypertension in all participants and fasting glucose in males were associated with quantitative changes in white matter. Prospective clinical studies should determine optimal blood pressure to reduce stroke and cognitive impairment during aging.

Influence of controlled encoding and retrieval facilitation on memory performance of patients with subcortical ischemic vascular dementia and Alzheimer's disease

Patients with subcortical ischemic vascular dementia (SIVD) perform better than Alzheimer's disease patients (AD) on the Free and Cued Recall Selective Reminding test (FCSRT). In this test, SIVD are able to overcome their strategic retrieval deficit, whereas AD patients, whose memory impairment is due to a hippocampal storage deficit, are not. However, the FCSRT does not assess the advantage passing from free to assisted learning, which is expected to be different in frontal and hippocampal damage. We compared SIVD, AD and healthy subjects on the free recall of a 15-word list not assisted at encoding and on the free and cued recall of the FCRST. Indexes of Encoding, Cueing and Total (measuring the advantage passing from the 15-word list free recall to the free and cued recall of the FCRST) were computed. The two groups performed comparably poorly on the free recall of the 15-word list, but SIVD outperformed AD patients in the free and cued recall of the FCSRT and took greater advantage than AD patients on both learning and recall when passing from the unassisted to the assisted paradigms. All indexes significantly predicted diagnostic group membership, but the Total Index showed the larger classification accuracy with 80% of AD and 71% of SIVD correctly classified. These results confirm that the FCRST is able to differentiate AD and SIVD patients with a good level of accuracy. However, the evaluation of memory performance variation as a function of support to encoding provides additional data able to increase diagnostic reliability.

The importance of comorbidities in ischemic stroke: Impact of hypertension on the cerebral circulation

Comorbidities are a hallmark of stroke that both increase the incidence of stroke and worsen outcome. Hypertension is prevalent in the stroke population and the most important modifiable risk factor for stroke. Hypertensive disorders promote stroke through increased shear stress, endothelial dysfunction, and large artery stiffness that transmits pulsatile flow to the cerebral microcirculation. Hypertension also promotes cerebral small vessel disease through several mechanisms, including hypoperfusion, diminished autoregulatory capacity and localized increase in blood-brain barrier permeability. Preeclampsia, a hypertensive disorder of pregnancy, also increases the risk of stroke 4-5-fold compared to normal pregnancy that predisposes women to early-onset cognitive impairment. In this review, we highlight how comorbidities and concomitant disorders are not only risk factors for ischemic stroke, but alter the response to acute ischemia. We focus on hypertension as a comorbidity and its effects on the cerebral circulation that alters the pathophysiology of ischemic stroke and should be considered in guiding future therapeutic strategies.

Increased risk of cognitive impairment and more severe brain lesions in hypertensive compared to non-hypertensive patients with cerebral small vessel disease

Although cerebral small vessel disease (SVD) is traditionally associated with aging and hypertension (HT), there are patients exhibiting sporadic SVD, free of HT. We aimed to investigate the differences in clinical and neuroradiological presentation in SVD patients in reference to the presence of HT as a risk factor (RF). Vascular RF, cognitive and functional status were evaluated in a cohort of 424 patients. Patients were classified in two groups based on the presence of HT. Severity of vascular lesions was assessed using 1.5 T magnetic resonance imaging with Age-Related White Matter Changes scale total score (tARWMC) and Fazekas scale periventricular (PV) and deep subcortical (DS) scores. No difference between groups in age and sex distribution was noted. In univariate analysis, HT was associated with vascular cognitive impairment (vCI) (OR 2.30, 1.53-3.45, P < 0.0001), functional status (OR 1.47, 1.11-1.95, P = 0.007), depression (OR 2.13, 1.23-3.70, P = 0.007), tARWMC (OR 1.10, 1.05-1.16 95% CI, P < 0.0001), Fazekas PV score (OR 1.34, 1.08-1.67 95% CI, P = 0.008), Fazekas DS score (OR 1.95, 1.44-2.63 95% CI, P < 0.0001) and total number of lacunes (OR 1.10, 1.02-1.18 95% CI, P = 0.009). Multivariate logistic regression analysis indicated that HT was an independent RF for vCI (OR 1.74, 1.09-2.76 95% CI, P = 0.020) and higher Fazekas DS score (OR 1.57, 1.11-2.22 95% CI, P = 0.011). The Kaplan-Meier curve of estimates of survival of SVD patients without vCI revealed a higher proportion of patients with HT progressing to vCI over time when compared to HT-free cases. In patients with sporadic SVD, HT is a contributing factor to worse clinical outcomes and neuroradiological presentation.

Mental speed is associated with the shape irregularity of white matter MRI hyperintensity load

Brain MRI white matter hyperintensities (WMHs) are common in elderly subjects. Their impact on cognition, however, appears highly variable. Complementing conventional scoring of WMH load (volume and location) by quantitative characterization of the shape irregularity of WMHs might improve the understanding of the relationship between WMH load and cognitive performance. Here we propose the "confluency sum score" (COSU) as a marker of the total shape irregularity of WMHs in the brain. The study included two independent patient samples: 87 cognitively impaired geriatric inpatients from a prospective neuroimaging study (iDSS) and 198 subjects from the National Alzheimer's Coordinating Center (NACC) database (132 with, 66 w/o cognitive impairment). After automatic segmentation and clustering of the WMHs on FLAIR (LST toolbox, SPM8), the confluency of the i-th contiguous WMH cluster was computed as confluency_i = [1/(36π)∙surface_i³/volume_i²]^1/3-1. The COSU was obtained by summing the confluency over all WMH clusters. COSU was tested for correlation with CERAD-plus subscores. Correlation analysis was restricted to subjects with at least moderate WMH load (≥ 13.5 ml; iDSS / NACC: n = 52 / 80). In the iDSS sample, among the 12 CERAD-plus subtests the trail making test A (TMT-A) was most strongly correlated with the COSU (Spearman rho = -0.345, p = 0.027). TMT-A performance was not associated with total WMH volume (rho = 0.147, p = 0.358). This finding was confirmed in the NACC sample (rho = -0.261, p = 0.023 versus rho = -0.040, p = 0.732). Cognitive performance in specific domains including mental speed and fluid abilities seems to be more strongly associated with the shape irregularity of white matter MRI hyperintensities than with their volume.

Metabolically healthy obesity and risk of leukoaraiosis; a population based cross-sectional study

Metabolically healthy obese (MHO) individual is known to be defended from the metabolic complications of obesity. Leukoaraiosis, which is commonly detected on brain magnetic resonance imaging (MRI), is now recognized as a risk of stroke, dementia and death. However, the association between MHO and the prevalence of leukoaraiosis is unclear. In this cross-sectional study of 796 participants who received a medical examination program, we investigated the association between MHO and the prevalence of leukoaraiosis. We used common clinical markers for definition of metabolic healthy status: blood pressure, fasting plasma glucose, triglycerides and high-density lipoprotein cholesterol concentrations. Obesity was defined by body mass index ≥25.0 kg/m². We diagnosed leukoaraiosis by fluid-attenuated inversion recovery without hypointensity on T1-weighted images or the presence of a hyperintensity on T2-weighted images. The crude prevalence proportion of leukoaraiosis was 44.5% (case/n = 171/384) in metabolically healthy nonobese (MHNO) individual, 46.3% (44/95) in MHO individual, 62.3% (114/183) in metabolically unhealthy nonobese (MUNO) individual or 56.6% (77/136) in MUO individual. The odds ratios of prevalence of leukoaraiosis were 1.19 (95% CI 0.74-1.90, p = 0.471) for MHO, 1.79 (1.22-2.62, p = 0.003) for MUNO and 1.56 (1.03-2.37, p = 0.037) for MUO individuals after adjusting for sex, age, smoking statues, habit of exercise and alcohol, compared with MHNO individual. We revealed that MHO individuals were not related with the higher risk of leukoaraiosis, whereas MUNO and MUO individuals were.

Effects of stressful life events on cerebral white matter hyperintensity progression

OBJECTIVE

Exposure to stressful events is associated with both occurrence of depression and also vascular disease. The objective of this study was to determine whether higher levels of stress exposure was related to measures of pathological brain aging, specifically white matter hyperintensity volumes, in older adults with and without depression.

METHODS

The sample included 130 depressed and 110 never-depressed older adults aged 60 years or older enrolled in a longitudinal study at an academic medical center. Participants completed clinical assessments, assessment of stressful event exposure and perceived stress, and magnetic resonance imaging at baseline and after 2 years. Analyses examined both cross-sectional and longitudinal relationships between stress measures and white matter hyperintensity volumes.

RESULTS

There were no statistically significant relationships observed between cross-sectional baseline stress measures and either baseline hyperintensity volume or 2-year change in hyperintensity volume. However, after controlling for demographic variables and baseline measures, change in stressor exposure was associated with change in hyperintensity volumes. In this analysis, increased stressor exposure was associated with greater increases in white matter hyperintensity volume, while reductions in stressor exposure were associated with less increase in hyperintensity volume. This relationship did not significantly differ based on the presence of either depression or medical comorbidities.

CONCLUSIONS

This work adds to a growing literature associating exposure to stressful events in later life with more rapid pathological brain aging. Work is needed to understand the physiological mechanisms by which stress exposure has this effect and examine whether stress reduction techniques may modify these observed outcomes. Copyright © 2016 John Wiley & Sons, Ltd.

The Spatial Associations of Cerebral Blood Flow and Spontaneous Brain Activities with White Matter Hyperintensities-An Exploratory Study Using Multimodal Magnetic Resonance Imaging

White matter hyperintensities (WMHs) have been reported to be correlated with functional brain changes, but the association of the specific WMHs distribution pattern with regional functional changes remains uncertain. The aim of this study is to explore the possible spatial correlation of WMH with changes in cerebral blood flow (CBF) and spontaneous brain activities in elderly using a novel approach. The WMHs, CBF, and spontaneous brain activities measured by intrinsic connectivity contrast (ICC), were quantified using multimodal magnetic resonance imaging for 69 elderly subjects. Such approach enables us to expand our search for newly identified correlated areas by drawing strengths of different modes and provides a means for triangulation as well as complementary insights. The results showed significant positive correlations between WMH volumes in the right superior corona radiata and CBF in the left supplementary motor area, as well as between WMH volumes in left anterior limb internal capsule and CBF in the right putamen. Significant correlations of regional WMH volumes and ICC were also detected between the right anterior corona radiata and the left cuneus, and the right superior occipital cortex, as well as between the right superior corona radiata and the left superior occipital cortex. These findings may suggest a regional compensatory functional enhancement accounting for the maintenance of cognitively normal status, which can be supported by the widely observed phenomenon that mild to moderate WMH load could have little effect on global cognitive performance.

Recent Advances in Leukoaraiosis: White Matter Structural Integrity and Functional Outcomes after Acute Ischemic Stroke

Leukoaraiosis, a radiographic marker of cerebral small vessel disease detected on T2-weighted brain magnetic resonance imaging (MRI) as white matter hyperintensity (WMH), is a key contributor to the risk and severity of acute cerebral ischemia. Prior investigations have emphasized the pathophysiology of WMH development and progression; however, more recently, an association between WMH burden and functional outcomes after stroke has emerged. There is growing evidence that WMH represents macroscopic injury to the white matter and that the extent of WMH burden on MRI influences functional recovery in multiple domains following acute ischemic stroke (AIS). In this review, we discuss the current understanding of WMH pathogenesis and its impact on AIS and functional recovery.

Early life risk factors for cerebrovascular disease: A systematic review and meta-analysis

OBJECTIVE

Cerebrovascular disease (CVD) causes subclinical brain vascular lesions detected using neuroimaging and childhood factors may increase later CVD risk.

METHODS

We searched MEDLINE, PsycINFO, and EMBASE, and meta-analyzed all available evidence on childhood (premorbid) IQ, socioeconomic status (SES), education, and subclinical CVD in later life. Overall odds ratios (OR), mean difference or correlation, and 95% confidence intervals (CIs) were calculated using random effects methods.

RESULTS

We identified 30 relevant studies (n = 22,890). Lower childhood IQ and lower childhood SES were associated with more white matter hyperintensities (WMH) (IQ: n = 1,512, r = -0.07, 95% CI -0.12 to -0.02, p = 0.007; SES: n = 243, deep WMH r = -0.18, periventricular WMH r = -0.146). Fewer years of education were associated with several CVD markers (n = 15,439, OR = 1.17, 95% CI 1.05 to 1.31, p = 0.003). No studies assessed early life factors combined.

CONCLUSIONS

Childhood IQ, SES, and education are associated with increased risk of CVD on neuroimaging in later life. Further studies are required to provide further evidence and thereby inform policy.

Impact of cerebral white matter changes on functionality in older adults: An overview of the LADIS Study results and future directions

The evidence on the clinical significance of cerebral white matter changes (WMC) has mounted over the past few decades. WMC are recognized as one of the neuroimaging features of cerebral small vessel disease, and are associated with various disturbances and a poor prognosis. The Leukoaraiosis and Disability (LADIS) Study has contributed substantially to this body of knowledge. LADIS is a European multicenter collaboration aimed at assessing the role of WMC as an independent predictor of the transition to disability in initially non-disabled patients aged 65-84 years. Besides the demonstration that severe WMC cause a more than double risk of transition from an autonomous to a dependent status after 3 years of follow-up, the LADIS Study has also provided evidence on the role of WMC in relation to the decline of cognitive and motor performances, depressive symptoms associated with aging and cerebrovascular diseases, the presence of urinary disturbances, and various neurological abnormalities. The possible role of other lesions (lacunar infarcts, cerebral atrophy, corpus callosum morphology) and microstructural abnormalities (diffusion-weighted imaging changes in normal appearing brain tissue and in WMC) has also been investigated. In the present article, we review the main results of the LADIS Study and offer some considerations for future developments in the field, paying attention to the potential use of WMC progression as a surrogate marker in intervention trials in cerebral small vessel diseases. We also discuss some therapeutic perspectives regarding the beneficial impact of physical activity on the risk of vascular cognitive impairment in patients with WMC.

White matter hyperintensities and geriatric syndrome: An important role of arterial stiffness

White matter hyperintensities (WMH) are defined as cerebral white matter changes presumed to be of vascular origin, bilateral and mostly symmetrical. They can appear as hyperintense on T2-weighted and fluid-attenuated inversion recovery sequences, and as isointense or hypointense on T1-weighted magnetic resonance imaging of the brain. WMH have been focused on because of their clinical importance as a risk factor for cerebrovascular diseases and cognitive impairment. WMH are associated with geriatric syndrome, which is defined by clinical symptoms characteristic of older adults, including cognitive and functional impairment and falls. Cerebral small vessel diseases, such as WMH, might play an important role as risk factors for cerebrovascular diseases, cognitive impairment and geriatric syndrome through the mechanism of arterial stiffness. However, the vascular, physiological and metabolic roles of arterial stiffness remain unclear. Basically, arterial stiffness indicates microvessel arteriosclerosis presenting with vascular endothelial dysfunction. These changes might arise from hemodynamic stress as a result of a "tsunami effect" on cerebral parenchyma. In the present article, we review the clinical characteristics of WMH, focusing particularly on two associations: (i) those between cerebral small vessel diseases including WMH and arterial stiffness; and (ii) those between WMH and geriatric syndrome.

Transcranial Parenchymal Sonographic Findings in Patients With Cerebral Small Vessel Disease: A Preliminary Study

OBJECTIVES

Patients with cerebral small vessel disease often present with various motor, cognitive, and emotional changes, including gait disturbances, parkinsonism, and depression. Substantia nigra hyperechogenicity, brain stem raphe hypoechogenicity, ventricle diameters, and sonographic characteristics of other brain structures on transcranial sonography have been increasingly used as biomarkers in a range of neurologic diseases. We aimed to explore the frequency and clinical correlates of transcranial sonographic findings in symptomatic patients with small vessel disease.

METHODS

In a cross-sectional study, neurologic, cognitive, and emotional statuses and transcranial sonographic and magnetic resonance imaging findings were compared between 102 patients with small vessel disease and 45 healthy age- and sex-matched control participants.

RESULTS

Compared to healthy controls, small vessel disease cases had more frequent brain stem raphe hypoechogenicity (55.9% versus 11.1%; P < .0001), substantia nigra hyperechogenicity (30.4% versus 11.1%; P = .022), and enlarged third ventricles (P < .0001). Substantia nigra hyperechogenicity correlated with gait disturbances, extrapyramidal features, and cognitive impairment. Brain stem raphe hypoechogenicity was associated with the diagnosis of depression. Enlargement of the third and lateral ventricles was more frequent in patients with cognitive impairment. Pathologic substantia nigra hyperechogenicity and enlarged ventricles were associated with the severity of cerebral ischemic lesions.

CONCLUSIONS

Transcranial sonography shows pathologic findings in a substantial number of patients with small vessel disease, probably reflecting disruption of frontostriatal pathways.

Shape abnormalities of the caudate nucleus correlate with poorer gait and balance: results from a subset of the LADIS study

OBJECTIVE

Functional deficits seen in several neurodegenerative disorders have been linked with dysfunction in frontostriatal circuits and with associated shape alterations in striatal structures. The severity of visible white matter hyperintensities (WMHs) on magnetic resonance imaging has been found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction.

METHODS

Magnetic resonance imaging scans and clinical gait/balance data (scores from the Short Physical Performance Battery [SPPB]) were sourced from 66 subjects in the previously published LADIS trial, performed in nondisabled individuals older than age 65 years with WMHs at study entry. Data were obtained at study entry and at 3-year follow-up. Caudate nuclei and putamina were manually traced using a previously published method and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis using the spherical harmonic shape description toolkit.

RESULTS

There was no correlation between the severity of WMHs and striatal volumes. Caudate nuclei volume correlated with performance on the SPPB at baseline but not at follow-up, with subsequent shape analysis showing left caudate changes occurred in areas corresponding to inputs of the dorsolateral prefrontal, premotor, and motor cortex. There was no correlation between putamen volumes and performance on the SPPB.

CONCLUSION

Disruption in frontostriatal circuits may play a role in mediating poorer physical performance in individuals with WMHs. Striatal volume and shape changes may be suitable biomarkers for functional changes in this population.

Chronic pain in "probable" vascular dementia: preliminary findings

BACKGROUND

In a previous study, the levels of pain reported by patients with "possible" vascular dementia (VaD) were higher than those reported by older individuals without dementia.

OBJECTIVE

To examine experienced pain in patients with "probable" VaD, confirmed by brain imaging.

STUDY DESIGN

Observational, cross sectional.

SETTING

Nursing home.

METHODS

The participants were 20 nursing home residents (14 females, 6 males) who met the NINDS-AIREN criteria for "probable" VaD and 22 nursing home residents with a normal mental status (18 females, 4 males). The patients were in a mild to moderate stage of dementia. All of the participants were suffering from arthritis/arthrosis or osteoporosis. Global cognitive functioning was measured by the Mini-Mental State Examination. Pain was assessed by the Coloured Analogue Scale (CAS: original and modified version) and the Faces Pain Scale. The Geriatric Depression Scale and the Symptom Checklist-90 were used to assess mood.

RESULTS

The main finding was that, after controlling for mood, the pain levels indicated by patients with "probable" VaD (M = 102.32; standard deviation [SD] = 53.42) were significantly higher than those indicated by the control group (M = 59.17; SD = 38.75), only according to the CAS modified version (F[1,29]) = 5.62, P = 0.01, η2  = 0.16).

CONCLUSION

As VaD patients may experience greater pain than controls, it is essential for prescribers to be aware of the presence of this neuropathology if these patients are to receive adequate treatment.

Diffusion tensor imaging, intracranial vascular resistance and cognition in middle-aged asymptomatic subjects

BACKGROUND

The contribution of traditional vascular risk factors to cognitive impairment and dementia is well known. However, in order to obtain possible targets for prevention of vascular cognitive impairment (VCI), it may be important to identify other early and noninvasive markers in asymptomatic middle-aged adults. The calculation of middle cerebral artery-pulsatility index (MCA-PI) is an ultrasonologic, noninvasive, validated and easily reproducible technique to assess increased distal resistance to blood flow. This study aims to assess the relationship between MCA-PI, microstructural white matter (WM) integrity and cognition in a middle-aged asymptomatic population.

METHODS

Ninety-five participants from the Barcelona-Asymptomatic Intracranial Atherosclerosis (AsIA) neuropsychology study were included. Subjects were 50-65 years old, free from dementia and without history of vascular disease. Transcranial color-coded duplex ultrasound examination was performed to assess MCA-PI as a measure of vascular resistance. WM integrity was evaluated by fractional anisotropy (FA) measurements of diffusion tensor images (DTI) acquired on a 3T-MRI. The neuropsychological battery was specifically selected to be sensitive to VCI, and included tests that were grouped into six cognitive domains: executive functioning, attention, verbal fluency, memory, visuospatial skills and psychomotor speed. A multivariate linear regression model adjusted for age, gender, years of education, diabetes and hypertension was performed.

RESULTS

MCA-PI was significantly associated with WM disintegration in different tracts (fornix, corticospinal and anterior thalamic), all p < 0.05 uncorrected. Both mean MCA-PI and mean FA of those significant tracts were independently associated with poor performance in attention, psychomotor speed, and visuospatial skills after adjustment for age, gender, years of education, and vascular risk factors (all p < 0.05). MCA-PI was independently associated with lower scores in all cognitive domains, except for visuospatial skills.

CONCLUSIONS

Our data suggest that MCA-PI may be related to WM disintegration and early vascular cognitive impairment in middle-aged subjects. Although further prospective studies are needed to provide evidence for its validity in longitudinal studies, our results support the proposal of including MCA-PI as part of clinical assessment in order to identify targets for VCI prevention.

Cerebrovascular Biomarker Profile Is Related to White Matter Disease and Ventricular Dilation in a LADIS Substudy

BACKGROUND

Small vessel disease (SVD) represents a common often progressive condition in elderly people contributing to cognitive disability. The relationship between cerebrospinal fluid (CSF) biomarkers and imaging correlates of SVD was investigated, and the findings were hypothesized to be associated with a neuropsychological profile of SVD.

METHODS

CSF SVD-related biomarkers [neurofilament light (NF-L), myelin basic protein (MBP), soluble amyloid precursor protein-β (sAPPβ), matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinase (TIMP)] were analysed in 46 non-demented elderly with imaging findings of SVD. We assessed the relationship between the CSF biomarkers and white matter hyperintensity (WMH) volume, diffusion-weighted imaging and atrophy as well as their association with neuropsychological profiles.

RESULTS

The WMH volume correlated with ventricular dilation, which was associated with executive function and speed and attention. Increased WMH and ventricular dilation were related to increased CSF levels of TIMP-1, NF-L and MBP and to decreased sAPPβ. A positive correlation was found between the CSF biomarker MMP-9 and WMH progression.

CONCLUSIONS

The link between progressive WMH and MMP-9 suggests an involvement of the enzyme in white matter degeneration. CSF TIMP-1, NF-L, MBP and sAPPβ may function as biological markers of white matter damage.

Analysis of Cerebral Blood Flow with Single Photon Emission Computed Tomography in Mild Subcortical Ischemic Vascular Dementia

PURPOSE

The mechanism of cognitive dysfunction of subcortical ischemic vascular dementia (SIVaD) is not yet fully understood. The objective of this study was to investigate and compare the distribution of regional cerebral perfusion (CP) change in the mild forms of SIVaD, a relatively homogeneous subtype of vascular dementia, using statistical parametric mapping (SPM) analysis of the technetium-99m hexamethylproplyeneamineoxime (Tc-99m HMPAO) single photon emission computed tomography (SPECT).

MATERIALS AND METHODS

A total of 28 patients with mild SIVaD and 33 healthy controls were prospectively recruited and underwent SPECT imaging studies between January 2012 and May 2013. SPECT was performed to measure the regional CP, and SPM was applied to the analysis of the SPECT data.

RESULTS

The regional CP was significantly decreased in the bilateral insula, anterior and posterior cingulated gyrus, precentral gyrus, and subcallosal gyrus as well as the right inferior parietal lobule in the SIVaD patients compared to the controls (corrected p = 0.01). The pattern of CP abnormality correlated well with those previously reported in later forms of SIVaD.

CONCLUSIONS

Reduction of CP in the brain areas mentioned was present earlier on in the natural course of SIVaD pathophysiology. Our study suggests that cognitive dysfunction of SIVaD may be related to these regional CP deficits.

Lacunar stroke, deep white matter disease and depression: a meta-analysis

BACKGROUND

Lacunar stroke is a small (<2 cm) infarction that accounts for approximately 20% of all strokes. While a third of all stroke patients experience depressive symptoms, the prevalence of depression in the lacunar stroke patient population is unclear. This meta-analysis aimed to synthesize the evidence on the effect of lacunar stroke and deep white matter disease on depressive symptoms.

METHODS

A systematic search of electronic databases was conducted, resulting in the inclusion of 12 studies. Analyses were performed on the effects of lacunar stroke, volume and location of lacunes on depression prevalence, and the effect on depression severity. The effects estimates were calculated in random-effects models.

RESULTS

None of the analyses produced statistically significant results. Lacunar stroke patients had a non-significantly higher prevalence of depression compared to patients with non-lacunar cerebrovascular diseases (OR = 1.46, 95% CI: 0.88-2.43, p = 0.15). Neither thalamic (OR = 1.37 (0.85-2.20), p = 0.19), deep white matter (RR = 1.16 (0.85-1.57), p = 0.35), multiple lacunes (OR = 1.34 (0.81-2.22), p = 0.25), or the volume of lacunes (MD = -4.71 (-351.59-342.18), p = 0.98) had an effect on depression prevalence. Lastly, lacunar stroke did not influence depressive symptom severity (MD = 0.96 (-1.57-3.48), p = 0.46).

CONCLUSIONS

The pooled group of patients with lacunar stroke and deep white matter disease appear to have a similar prevalence of depression compared to those with other types of cerebrovascular diseases. However, the small number of studies, heterogeneous comparison groups, and high statistical heterogeneity between studies posed an obstacle to the meta-analysis. To determine appropriate screening and treatment approaches, future research will need to separate lacunar stroke and deep white matter disease patients, and include larger sample sizes and healthy control groups to determine their distinct contributions to depression.

The nuances of cognition and depression in older adults: the need for a comprehensive assessment

OBJECTIVES

This study aimed to examine the confluence of depression, cognitive impairment, and vascular risk factors in older individuals.

METHODS

The study uses baseline data from the National Alzheimer's Coordinating Center. Data were collected across Alzheimer's Disease Centers in the USA. The sample included 12,634 individuals (cognitive intact = 8022; amnestic mild cognitive impairment [aMCI] = 3652; nonamnestic MCI [nonaMCI] = 960). The Geriatric Depression Scale assessed depression; the Trail Making Test assessed executive function.

RESULTS

The proportion of participants with depression was higher in the aMCI (18%) and nonaMCI group (21%) as compared with that in the cognitively intact group (8%); there was no difference in rates of depression between aMCI and nonaMCI groups. The proportion of participants with executive dysfunction differed between nondepressed and depressed individuals for the cognitively intact (8% vs. 12%) and aMCI groups (28% vs. 35%), but not for the nonaMCI group (37% vs. 41%). Nine percent of the cognitively intact group had executive dysfunction compared with 31% of the aMCI group and 40% of the nonaMCI group. The proportion of participants with hypertension was greater in individuals with executive dysfunction compared with those with no executive deficits; the presence of hypertension was not associated with depression severity.

CONCLUSIONS

The confluence of vascular risk factors, episodic memory impairment, and depression and executive dysfunction highlights the need for comprehensive assessment of depressed older adults that can aid clinicians in the formulation of treatment planning and inform clinicians and researchers about long-term prognosis.

Neglect performance in acute stroke is related to severity of white matter hyperintensities

BACKGROUND

Leukoaraiosis and its progression have longitudinally been associated with cognitive decline and dementia. Its role in acute cognitive function and response to acute cerebral ischemia is less well understood. We evaluated whether the presence and extent of leukoaraiosis, or white matter hyperintensities (WMH), had an impact on performance on tests of hemispatial neglect in acute ischemic stroke patients.

METHODS

A series of 206 acute ischemic right-hemispheric stroke patients at Johns Hopkins Hospital underwent brain MRI and cognitive assessment for hemispatial neglect within 5 days of symptom onset. Error rates on neglect tests were evaluated, as were dichotomized measures of neglect, including 'any', 'severe' or 'worst' neglect, based on Z scores of at least 2 on 1, 2 or 3 tests (respectively) within a neglect battery. Acute infarct volumes were measured on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery images were reviewed for WMH, using the Cardiovascular Health Study (CHS) rating scale (ranging from 0 to 9, with 9 being 'most extensive'). Linear regression was used to evaluate 'error rate on neglect test' as the dependent variable, as a measure of neglect severity, with 'WMH category' as the primary independent variable, including adjustment for age, sex, race and infarct volume (on DWI). Logistic regression was used to evaluate a binary definition of neglect (defined as above) relative to the same independent variable and covariates.

RESULTS

Each 1-point increase in CHS leukoaraiosis category was associated with 1.20-fold increased odds (95% CI: 1.00-1.43) of having any neglect, 1.23-fold increased odds (95% CI: 1.02-1.49) of having severe neglect and 1.33-fold increased odds of having worst neglect (95% CI: 1.01-1.76) after adjusting for infarct volume, age, sex and race. Increasing age and infarct size were also important predictors of neglect severity, with a 2.36% higher error rate (95% CI: 0.75-3.97%) on the line cancellation test associated with each category increase in CHS score; similar results were found for each of the neglect tests. Line cancellation neglect scores were worse in individuals with both severe WMH and large infarcts (p interaction, unadjusted=0.03).

CONCLUSIONS

More severe leukoaraiosis is associated with more hemispatial neglect after acute ischemic stroke, independent of infarct volume, age and sex. We found not only more frequent neglect but also more severe neglect, based on error rates on neglect tests, in individuals with increasing leukoaraiosis. This emphasizes the importance of preexisting brain microvascular disease in outcomes of stroke patients. Further studies of the possible mechanism behind this association are needed.

Executive dysfunction correlates with caudate nucleus atrophy in patients with white matter changes on MRI: a subset of LADIS

White matter changes (WMC) are common magnetic resonance imaging (MRI) findings, particularly in the elderly. Recent studies such as the Leukoaraiosis and Disability Study (LADIS) have found that WMC relate to adverse outcomes including cognitive impairment, depression, disability, unsteadiness and falls in cross-sectional and follow-up studies. Frontostriatal (or frontosubcortical) brain circuits may serve many of these functions, with the caudate nuclei playing a role in convergence of cognitive functions. This study aimed to determine whether reduced caudate volume relates to cognitive functions (executive functions, memory functions and speed of processing) and WMC. We determined caudate nuclei volumes, through manual tracing, on a subgroup of the LADIS study (n=66) from four centres with baseline and 3-year follow-up MRI scans. Regression analysis was used to assess relationships between caudate volume, cognitive function and WMC. Severity of WMC did not relate to caudate volume. Smaller caudate volumes were significantly associated with poorer executive functioning at baseline and at 3 years, but were not associated with scores of memory or speed of processing. Thus, in patients with WMC, a surrogate of small vessel disease, caudate atrophy relates to the dysexecutive syndrome, supporting the role of caudate as an important part of the frontostriatal circuit.

The vascular depression hypothesis: mechanisms linking vascular disease with depression

The 'Vascular Depression' hypothesis posits that cerebrovascular disease may predispose, precipitate or perpetuate some geriatric depressive syndromes. This hypothesis stimulated much research that has improved our understanding of the complex relationships between late-life depression (LLD), vascular risk factors, and cognition. Succinctly, there are well-established relationships between LLD, vascular risk factors and cerebral hyperintensities, the radiological hallmark of vascular depression. Cognitive dysfunction is common in LLD, particularly executive dysfunction, a finding predictive of poor antidepressant response. Over time, progression of hyperintensities and cognitive deficits predicts a poor course of depression and may reflect underlying worsening of vascular disease. This work laid the foundation for examining the mechanisms by which vascular disease influences brain circuits and influences the development and course of depression. We review data testing the vascular depression hypothesis with a focus on identifying potential underlying vascular mechanisms. We propose a disconnection hypothesis, wherein focal vascular damage and white matter lesion location is a crucial factor, influencing neural connectivity that contributes to clinical symptomatology. We also propose inflammatory and hypoperfusion hypotheses, concepts that link underlying vascular processes with adverse effects on brain function that influence the development of depression. Testing such hypotheses will not only inform the relationship between vascular disease and depression, but also provide guidance on the potential repurposing of pharmacological agents that may improve LLD outcomes.

Prevalence and burden of gait disorders in elderly men and women aged 60-97 years: a population-based study

Background

Although gait disorders are common in the elderly, the prevalence and overall burden of these disorders in the general community is not well defined.

Methods

In a cross-sectional investigation of the population-based Bruneck Study cohort, 488 community-residing elderly aged 60–97 years underwent a thorough neurological assessment including a standardized gait evaluation. Gait disorders were classified according to an accepted scheme and their associations to falls, neuropsychological measures, and quality of life were explored.

Results

Overall, 32.2% (95% confidence interval [CI] 28.2%–36.4%) of participants presented with impaired gait. Prevalence increased with age (p<0.001), but 38.3% (95%CI 30.1%–47.3%) of the subjects aged 80 years or older still had a normally preserved gait. A total of 24.0% (95%CI 20.4%–28.0%) manifested neurological gait disorders, 17.4% (14.3%–21.0%) non-neurological gait problems, and 9.2% (6.9%–12.1%) a combination of both. While there was no association of neurological gait disorders with gender, non-neurological gait disorders were more frequent in women (p = 0.012). Within the group of neurological gait disorders 69.2% (95%CI 60.3%–76.9%) had a single distinct entity and 30.8% (23.1%–39.7%) had multiple neurological causes for gait impairment. Gait disorders had a significant negative impact on quantitative gait measures, but only neurological gait disorders were associated with recurrent falls (odds ratio 3.3; 95%CI 1.4–7.5; p = 0.005 for single and 7.1; 2.7–18.7; p<0.001 for multiple neurological gait disorders). Finally, we detected a significant association of gait disorders, in particular neurological gait disorders, with depressed mood, cognitive dysfunction, and compromised quality of life.

Conclusions

Gait disorders are common in the general elderly population and are associated with reduced mobility. Neurological gait disorders in particular are associated with recurrent falls, lower cognitive function, depressed mood, and diminished quality of life.

Treatment for cerebral small vessel disease: effect of relaxin on the function and structure of cerebral parenchymal arterioles during hypertension

We investigated the effect of hypertension on the function and structure of cerebral parenchymal arterioles (PAs), a major target of cerebral small vessel disease (SVD), and determined whether relaxin is a treatment for SVD during hypertension. PAs were isolated from 18-wk-old female normotensive Wistar-Kyoto (WKY) rats, spontaneous hypertensive rats (SHRs), and SHRs treated with human relaxin 2 for 14 d (4 μg/h; n=8/group) and studied using a pressurized arteriograph system. Hypertension reduced PA inner diameter (58±3 vs. 49±3 μm at 60 mmHg in WKY rats, P<0.05), suggesting inward remodeling that was reversed by relaxin (56±4 μm, P<0.05). Relaxin also increased PA distensibility in SHRs (34±2 vs. 10±2% in SHRs, P<0.05). Relaxin was detected in cerebrospinal fluid (110±30 pg/ml) after systemic administration, suggesting that it crosses the blood-brain barrier (BBB). Relaxin receptors (RXFP1/2) were not detected in cerebral vasculature, but relaxin increased vascular endothelial growth factor (VEGF) and matrix metalloproteinase 2 (MMP-2) expression in brain cortex. Inhibition of VEGF receptor tyrosine kinase (axitinib, 4 mg/kg/d, 14 d) had no effect on increased distensibility with relaxin, but caused outward hypertrophic remodeling of PAs from SHRs. These results suggest that relaxin crosses the BBB and activates MMP-2 in brain cortex, which may interact with PAs to increase distensibility. VEGF appears to be involved in remodeling of PAs, but not relaxin-induced increased distensibility.

Geriatric syndromes--vascular disorders?

The term geriatric syndrome is used to characterize multifactorial clinical conditions among older people which are not subsumed readily into disease entities, but which nevertheless predispose older people to disability and death. Commonly included are frailty, dementia, delirium, incontinence, falls, and dizziness. Geriatric syndromes are common among older people: in a recent survey, 50% of those aged more than 65 had one or more of these conditions. Better methods for prevention and treatment are needed, but current strategies have lacked a coherent conceptual and diagnostic framework. Prevention and interventions need to be targeted at earlier ages, with geriatrics expertise needed in the definition and operationalization of these complex entities. In this review we consolidate evidence that vascular disorders, including vascular ageing and vascular diseases, are key etiological factors of geriatric syndromes. Identifying this vascular dimension would offer opportunities for more efficient preventive strategies and mandates earlier intervention, especially for women, among whom vascular disease is often expressed more insidiously than among men. This would entail a sensitization of the health care system to the systematic detection of the syndromes, which are currently underdiagnosed. Further disentangling of the mechanisms of vascular ageing may offer therapies for vascular diseases and geriatric syndromes alike.

Confirmatory factor analysis of the Neuropsychological Assessment Battery of the LADIS study: a longitudinal analysis

Age-related white matter changes have been associated with cognitive functioning, even though their role is not fully understood. This work aimed to test a 3-factor model of the neuropsychological assessment battery and evaluate how the model fit the data longitudinally. Confirmatory factor analysis (CFA) was used to investigate the dimensions of a structured set of neuropsychological tests administered to a multicenter, international sample of independent older adults (LADIS study). Six hundred and thirty-eight older adults completed baseline neuropsychological, clinical, functional and motor assessments, which were repeated each year for a 3-year follow-up. CFA provided support for a 3-factor model. These factors involve the dimensions of executive functions, memory functions, and speed and motor control abilities. Performance decreased in most neuropsychological measures. Results showed that executive functioning, memory and speed of motor abilities are valid latent variables of neuropsychological performance among older adults, and that this structure is relatively consistent longitudinally, even though performance decreases with time.

Atrophy of the left dorsolateral prefrontal cortex is associated with poor performance in verbal fluency in elderly poststroke women

This study aimed to investigate the association between atrophy in the prefrontal cortex with executive function and verbal fluency in elderly male and female patients poststroke. Thirty elderly female patients with non-aphasic ischemic stroke aged ≥ 60 years and 30 age-matched non-aphasic male patients with ischemic stroke were recruited. Automatic magnetic resonance imaging segmentation was used to assess the volume of the whole prefrontal cortex, along with its subdivisions: anterior cingulate cortex, orbitofrontal cortex and dorsolateral prefrontal cortex. The Semantic Verbal Fluency Test was administered at 3 and 15 months poststroke. At 3 months poststroke, left dorsolateral prefrontal cortex volume was significantly correlated with Verbal Fluency Test score in female patients only (partial coefficient = 0.453, P = 0.045), after controlling for age, education, diabetes, neurological deficit, white matter lesions volume, as well as the location and volume of infarcts. At 15 months poststroke, there remained a significant association between the left dorsolateral prefrontal cortex volume and Verbal Fluency Test (partial coefficient = 0.661, P = 0.001) and between the left prefrontal cortex volume and Verbal Fluency Test (partial coefficient = 0.573, P = 0.004) in female patients after the same adjustments. These findings indicate that atrophy of the left dorsolateral prefrontal cortex contributes to the impairment of verbal fluency in elderly female patients with stroke. Sex differences may be present in the neuropsychological mechanisms of verbal fluency impairment in patients with stroke.

The association between cognitive function and white matter lesion location in older adults: a systematic review

Background

Maintaining cognitive function is essential for healthy aging and to function autonomously within society. White matter lesions (WMLs) are associated with reduced cognitive function in older adults. However, whether their anatomical location moderates these associations is not well-established. This review systematically evaluates peer-reviewed evidence on the role of anatomical location in the association between WMLs and cognitive function.

Methods

In accordance with the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement, databases of EMBASE, PUBMED, MEDLINE, and CINAHL, and reference lists of selected papers were searched. We limited our search results to adults aged 60 years and older, and studies published in the English language from 2000 to 2011. Studies that investigated the association between cognitive function and WML location were included. Two independent reviewers extracted: 1) study characteristics including sample size, sample characteristic, and study design; 2) WML outcomes including WML location, WML quantification method (scoring or volume measurement), strength of the MRI magnet in Tesla, and MRI sequence used for WML detection; and 3) cognitive function outcomes including cognitive tests for two cognitive domains of memory and executive function/processing speed.

Results

Of the 14 studies included, seven compared the association of subcortical versus periventricular WMLs with cognitive function. Seven other studies investigated the association between WMLs in specific brain regions (e.g., frontal, parietal lobes) and cognitive function. Overall, the results show that a greater number of studies have found an association between periventricular WMLs and executive function/processing speed, than subcortical WMLs. However, whether WMLs in different brain regions have a differential effect on cognitive function remains unclear.

Conclusions

Evidence suggests that periventricular WMLs may have a significant negative impact on cognitive abilities of older adults. This finding may be influenced by study heterogeneity in: 1) MRI sequences, WML quantification methods, and neuropsychological batteries; 2) modifying effect of cardiovascular risk factors; and 3) quality of studies and lack of sample size calculation.

Identifying the neural correlates of executive functions in early cerebral microangiopathy: a combined VBM and DTI study

Cerebral microangiopathy (CMA) has been associated with executive dysfunction and fronto-parietal neural network disruption. Advances in magnetic resonance imaging allow more detailed analyses of gray (e.g., voxel-based morphometry-VBM) and white matter (e.g., diffusion tensor imaging-DTI) than traditional visual rating scales. The current study investigated patients with early CMA and healthy control subjects with all three approaches. Neuropsychological assessment focused on executive functions, the cognitive domain most discussed in CMA. The DTI and age-related white matter changes rating scales revealed convergent results showing widespread white matter changes in early CMA. Correlations were found in frontal and parietal areas exclusively with speeded, but not with speed-corrected executive measures. The VBM analyses showed reduced gray matter in frontal areas. All three approaches confirmed the hypothesized fronto-parietal network disruption in early CMA. Innovative methods (DTI) converged with results from conventional methods (visual rating) while allowing greater spatial and tissue accuracy. They are thus valid additions to the analysis of neural correlates of cognitive dysfunction. We found a clear distinction between speeded and nonspeeded executive measures in relationship to imaging parameters. Cognitive slowing is related to disease severity in early CMA and therefore important for early diagnostics.

Cognition and Hemodynamics

The relationship between cerebral hemodynamics and cognitive performance has increasingly become recognized as a major challenge in clinical practice for older adults. Both diabetes and hypertension worsen brain perfusion and are major risk factors for cerebrovascular disease, stroke and dementia. Cerebrovascular reserve has emerged as a potential biomarker for monitoring pressure-perfusion-cognition relationships. Endothelial dysfunction and inflammation, microvascular disease, and mascrovascular disease affect cerebral hemodynamics and play an important role in pathohysiology and severity of multiple medical conditions, presenting as cognitive decline in the old age. Therefore, the identification of cerebrovascular vascular reactivity as a new therapeutic target is needed for prevention of cognitive decline late in life.

Small vessel cerebrovascular disease in older adults

‘Cerebral small vessel disease’ is common in older adults and is an important cause of morbidity, functional impairment and cognitive decline. Small vessel disease is a collective term used to describe a number of underlying pathological processes and neuroimaging findings, such as lacunar infarcts, white matter lesions and microhaemorrhages.

With readily available neuroimaging, diagnostic accuracy has improved; however, the management of small vessel disease and prevention of cognitive decline remains uncertain. Treatment of conventional vascular risk factors may be appropriate, but future research is required to provide definitive answers. We have conducted a comprehensive literature review of cerebral small vessel disease in older adults. This highlights the clinical sequelae and underlying pathological processes, whilst discussing novel diagnostic neuroimaging and therapeutic strategies.

Vulnerability: the crossroads of frailty and delirium

Frailty and delirium, although seemingly distinct syndromes, both result in significant negative health outcomes in older adults. Frailty and delirium may be different clinical expressions of a shared vulnerability to stress in older adults, and future research will determine whether this vulnerability is age related, pathological, genetic, environmental, or most likely, a combination of all of these factors. This article explores the clinical overlap of frailty and delirium, describes possible pathophysiological mechanisms linking the two, and proposes research opportunities to further knowledge of the interrelationships between these important geriatric syndromes. Frailty, a diminished ability to compensate for stressors, is generally viewed as a chronic condition, whereas delirium is an acute change in attention and cognition, but there is a developing literature on transitions in frailty status around acute events, as well as on delirium as a chronic, persistent condition. If frailty predisposes an individual to delirium, and delirium delays recovery from a stressor, then both syndromes may contribute to a downward spiral of declining function, increasing risk, and negative outcomes. In addition, frailty and delirium may have shared pathophysiology, such as inflammation, atherosclerosis, and chronic nutritional deficiencies, which will require further investigation. The fields of frailty and delirium are rapidly evolving, and future research may help to better define the interrelationship of these common and morbid geriatric syndromes. Because of the heterogeneous pathophysiology and presentation associated with frailty and delirium, typical of all geriatric syndromes, multicomponent prevention and treatment strategies are most likely to be effective and should be developed and tested.

2001-2011: A Decade of the LADIS (Leukoaraiosis And DISability) Study: What Have We Learned about White Matter Changes and Small-Vessel Disease?

Over the last 20 years, evidence about the clinical correlates of cerebral white matter changes (WMC; also called leukoaraiosis) has been accumulating. WMC are now listed among the neuroimaging expressions of cerebral small-vessel disease and are no longer considered an innocuous finding because they are associated, in cross-sectional surveys, with various disturbances and, in follow-up studies, with poor prognosis. The Leukoaraiosis And DISability (LADIS) study has contributed substantially to this body of knowledge. LADIS is a European multicenter collaboration that was started in 2001 with the aim of assessing the independent role of WMC in predicting disability in subjects aged 65-84. The main results of the LADIS study have been released in 2009 with the demonstration that severe WMC more than double the risk of transition from an autonomous to a dependent status after 3 years of follow-up. The LADIS study has also contributed more focused substudies assessing the possible role of WMC in the decline of cognitive and motor performances, depressive symptoms associated with aging and cerebrovascular diseases, urinary disturbances, and also the role of other brain lesions (lacunar infarcts, cerebral atrophy, and corpus callosum morphology). The LADIS study provides a good example of harmonization of instruments (MRI protocol, clinical, neuropsychological, and functional scales) within an international collaboration. Currently, the LADIS study is providing data about the natural history of WMC. In this paper, we review the background and the main results of the LADIS study. This review puts forward some considerations for future studies in the field.

Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype

Past work demonstrated that late-life depression is associated with greater severity of ischemic cerebral hyperintense white matter lesions, particularly frontal lesions. However, these lesions are also associated with other neuropsychiatric deficits, so these clinical relationships may depend on which fiber tracts are damaged. We examined the ratio of lesion to nonlesioned white matter tissue within multiple fiber tracts between depressed and nondepressed elders. We also sought to determine if the AGTR1 A1166C and BDNF Val66Met polymorphisms contributed to vulnerability to lesion development in discrete tracts. The 3T structural MR images and blood samples for genetic analyses were acquired on 54 depressed and 37 nondepressed elders. Lesion maps were created through an automated tissue segmentation process and applied to a probabilistic white matter fiber tract atlas allowing for identification of the fraction of the tract occupied by lesion. The depressed cohort exhibited a significantly greater lesion ratio only in the left upper cingulum near the cingulate gyrus (F((1,86)) = 4.62, P = 0.0344), supporting past work implicating cingulate dysfunction in the pathogenesis of depression. In the 62 Caucasian subjects with genetic data, AGTR1 C1166 carriers exhibited greater lesion ratios across multiple tracts including the anterior thalamic radiation and inferior fronto-occipital fasciculus. In contrast, BDNF Met allele carriers exhibited greater lesion ratios only in the frontal corpus callosum. Although these findings did not survive correction for multiple comparisons, this study supports our hypothesis and provides preliminary evidence that genetic differences related to vascular disease may increase lesion vulnerability differentially across fiber tracts.