Cerebral white matter changes and geriatric syndromes: is there a link?

Global trends in the research on older population dizziness/vertigo: a 20-year bibliometric and visualization analysis

OBJECTIVE

Dizziness or vertigo in older population frequently presents in clinical settings, yet its etiology remains elusive. The objective of this study was to delineate global trends and identify frontiers in research concerning dizziness or vertigo among older population.

METHODS

We searched the research literature published from 2003 to 2022 on older population with dizziness or vertigo using two databases from the Web of Science Core Collection. A bibliometric and visualization analysis was conducted. Bibliometric tools facilitated co-authorship, co-citation, and keyword co-occurrence analyses, encompassing countries or regions, institutions, authors, journals, and references.

RESULTS

The analysis included 1322 publications authored by 6524 individuals from 2244 institutions across 67 countries or regions, spanning 92 subject categories. A steady increase in publications was noted from 2003 to 2022. The University of Munich, Harvard University, and the University of California System emerged as leading institutions with the highest publication outputs. The United States, Germany, and China were predominant in publication counts. Eva Grill was identified as the most prolific author. Otology & Neurotology and Geriatrics & Gerontology emerged as the most prolific journal and subject category, respectively. The most prevalent keywords were "dizziness", "vertigo", "falls", and "geriatric", with "management", "gait", and "association" recognized as the principal research hotspots.

CONCLUSION

This study provides a systematic analysis of global scientific research on older population dizziness/vertigo, revealing significant advancements in understanding over the past two decades. Management, gait, and association have emerged as the primary research focuses on recent years. These findings offer valuable insights for directing current research efforts to capture prevailing trends and explore new frontiers in this field.

Resistance Training Increases White Matter Density in Frail Elderly Women

We aimed to investigate the effects of maternal obesity on brain structure and metabolism in frail women, and their reversibility in response to exercise. We recruited 37 frail elderly women (20 offspring of lean/normal-weight mothers (OLM) and 17 offspring of obese/overweight mothers (OOM)) and nine non-frail controls to undergo magnetic resonance and diffusion tensor imaging (DTI), positron emission tomography with Fluorine-18-fluorodeoxyglucose (PET), and cognitive function tests (CERAD). Frail women were studied before and after a 4-month resistance training, and controls were studied once. White matter (WM) density (voxel-based morphometry) was higher in OLM than in OOM subjects. Exercise increased WM density in both OLM and OOM in the cerebellum in superior parietal regions in OLM and in cuneal and precuneal regions in OOM. OLM gained more WM density than OOM in response to intervention. No significant results were found from the Freesurfer analysis, nor from PET or DTI images. Exercise has an impact on brain morphology and cognition in elderly frail women.

Do executive functions explain older adults' health-related quality of life beyond event-based prospective memory?

Previous work has shown that event-based prospective memory (EBPM) predicted health-related quality of life (HrQoL). In the present study, we aimed to examine whether the relationship between EBPM and HrQoL extended to life satisfaction, and whether it persisted after controlling for other cognitive functions related to EBPM, namely executive functions and retrospective memory. We tested two models using structural equation modeling with latent variables in a sample of older adults. In the first model, we assessed whether EBPM predicted life satisfaction and HrQoL; in the second model, we controlled for retrospective memory and executive functions. The first model indicated that EBPM was related to HrQoL. However, in the second model, this relationship was eliminated by executive functions; life satisfaction was not related to any of the cognitive variables. Findings corroborated the link between HrQoL and EBPM, suggesting that such relationship stems from executive functions rather than retrospective memory.

Delirium in Frail Older Adults

Delirium and frailty are prevalent geriatric syndromes and important public health issues among older adults. The prevalence of delirium among hospitalized older adults ranges from 15% to 75%, while that of frailty ranges from 12% to 24%. The exact pathophysiology of these two conditions has not been clearly identified, although several hypotheses have been proposed. However, these conditions are considered to be multifactorial in etiology and are associated with inflammation related to aging, alterations in vascular systems, genetics, and nutritional deficiency. Furthermore, clinically, they are significantly associated with frailty, which increases the risk of delirium by almost two- to three-fold among hospitalized older adults. With their multifactorial etiology and unknown pathophysiology, current evidence supports more practical multicomponent patient-centered approaches to prevent and manage delirium with frailty among hospitalized older adults. These comprehensive and organized bundled approaches can identify high-risk patients with frailty and more effectively manage their delirium.

Relation of arterial stiffness with postural control in older people

PURPOSE

Arterial stiffness generates vascular alterations that may cause balance disorders and falls. This study aimed to investigate the possible link between arterial stiffness and postural control under different sensorial conditions in patients over 65 years.

METHODS

Carotid-femoral pulse wave velocity (PWV) was measured in 47 participants aged over 65 years to evaluate their arterial stiffness (high PWV). Twenty-seven participants (mean age = 70.52 ± 4.02 years, 22 females) had a normal PWV (< 10 m s^-1) and 20 participants (mean age = 75.93 ± 6.11 years; 15 females) had a high PWV (≥ 10 m s^-1). Postural control was evaluated using a force platform in four postural conditions: eyes open (EO) 1, eyes closed (EC), eyes open with a dual task (DT) and eyes open again (EO2). Using sway path traveled and surface covered by the center of foot pressure, we calculate the length function of surface (LFS). This ratio provides information about the precision (surface) of postural control and the effort made (length) by the subjects.

RESULTS

After an age-adjustment, LFS was lower in EO than in EC and DT in both groups (p ≤ 0.001). LFS was higher in participants with high PWV both in eyes open and eyes closed conditions (p < 0.05). LFS increased when PWV increased in EO (p < 0.01) and EC conditions (p < 0.001) but not when a dual task was performed.

CONCLUSION

Difficulties in maintaining equilibrium under a dual-task condition are more pronounced in people with increased arterial stiffness. These data suggest that understanding of the influence of the arterial stiffness level on specific balance control parameters could contribute to propose better balance-oriented rehabilitation programs in older adults in an attempt to prevent fall.

Relationship between androgenic alopecia and white matter hyperintensities in apparently healthy subjects

A healthy brain is essential for living a longer and fuller life. Detecting asymptomatic white matter hyperintensities (WMHs) may be clinically important in terms of treatment and prognostic evaluation. WMHs in brain may reflect brain aging. Androgenic alopecia (AGA) is associated with significant cardiovascular risk factors that also have a negative impact on brain aging. The main purpose of present study was to know whether alopecia might provide predictive information of WMHs that may be considered as a surrogate marker of cerebral small vessel disease which is related to arteriolosclerosis and vascular risk factors. From January 2017 to March 2018, 256 cases were enrolled consecutively. Patients under 18 years old, older than 90 years old, known to be affected by neurodegenerative diseases, demyelinating disorders or stroke and/or a brain tumor, were excluded from the study. A 4-point cerebral white matter Magnetic Resonance Imaging (MRI) hyperintensities scoring system, the Fazekas scale, was used to evaluate brain aging. Presence of AGA was evaluated with inspection according to Hamilton-Norwood classification system (grade I to VII). Two hundred eleven (82%) of individuals had mild alopecia (grade I, II, III), 28 (11%) had moderate alopecia (grade IV, V) and 17 (7%) had severe alopecia (grade VI, VII). Frequency of abnormal WMHs was significantly higher in patients with AGA compared to the without AGA. Hypertension (HT) (95% confidence interval [CI]: 1.873-9.487, p < 0.001) and the AGA (95% CI: 2.989-12.916, p < 0.0001) were independent determinants of abnormal WMHs. AGA may be regarded as a surrogate marker of asymptomatic WMHs which is related to arteriolosclerosis and vascular risk factors that has a significant impact on people's life.

Do Older Adults with Overactive Bladder Demonstrate Impaired Executive Function Compared to Their Peers Without OAB?

Background

Maintaining urinary continence is not an automatic process, but relies on continuous processing of sensory signals from the bladder and suppression of the desire to void. Urinary incontinence (UI) and lower urinary tract symptoms (LUTS), including urinary urgency, frequency, and nocturia are highly prevalent among the general population. This prevalence rises in association with increasing age, and this may be in part due to changes in the central nervous system rather than the urinary tract. The aim of this study was to assess if older adults with overactive bladder (OAB) had demonstrable impairment in executive function.

Methods

This was a cross-sectional study comparing the performance of adults aged 65 and over with and without OAB on two cognitive tests, the Trail Making Test B (TMT-B) and simple reaction time (SRT). OAB was defined as urgency, with at least weekly urgency incontinence and a daytime urinary frequency of 8 or more. The control group were defined as a Bladder control Self-Assessment Questionnaire (B-SAQ) score of ≤4.

Results

56 participants were recruited, of whom 35 met criteria for OAB. The OAB group took significantly longer to complete the TMT-B than the control group (103s vs. 77s, p = .003). There was no difference in the SRT.

Conclusions

In this sample of older adults, OAB was associated with measurable slower performance on the TMT-B, suggesting that impaired executive function is associated with OAB.

Overactive Bladder in Frail Older Adults

Overactive bladder (OAB) and frailty are multidimensional syndromes, and the prevalence of both increases with age. Little evidence exists for a direct association between OAB and frailty, but urinary urgency may well be a precursor of frailty in older people. Frail older adults are no less deserving of treatment than fit older adults, and lifestyle, behavioral, and pharmacological interventions remain the primary options for treatment, with some evidence for efficacy. Data on onabotulinumtoxinA therapy or percutaneous tibial nerve stimulation in frail older adults are sparse. Frail older adults are often excluded from drug trials, but evidence is accumulating that antimuscarinics and, to a lesser extent, beta-adrenergic agonists are safe, well-tolerated, and effective in older adults. Cognitive impairment associated with frailty should not be used as justification for avoiding the use of antimuscarinics. More studies are required to better understand the association between OAB and frailty, as both are associated with poor outcomes and may be amenable to intervention. Drug trials for OAB treatments should be encouraged to include frail older adults, as this population is highly affected yet often excluded.

Physical Performance and Risk of Postoperative Delirium in Older Adults Undergoing Aortic Valve Replacement

Background

Delirium is a major risk factor for poor recovery after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). It is unclear whether preoperative physical performance tests improve delirium prediction.

Objective

To examine whether physical performance tests can predict delirium after SAVR and TAVR, and adapt an existing delirium prediction rule for cardiac surgery, which includes Mini-Mental State Examination (MMSE), depression, prior stroke, and albumin level.

Design

Prospective cohort, 2014-2017.

Setting

Single academic center.

Subjects

A total of 187 patients undergoing SAVR (n=77) or TAVR (n=110).

Methods

The Short Physical Performance Battery (SPPB) score was calculated based on gait speed, balance, and chair stands (range: 0-12 points, lower scores indicate poor performance). Delirium was assessed using the Confusion Assessment Method. We fitted logistic regression to predict delirium using SPPB components and risk factors of delirium.

Results

Delirium occurred in 35.8% (50.7% in SAVR and 25.5% in TAVR). The risk of delirium increased for lower SPPB scores: 10-12 (28.2%), 7-9 (34.5%), 4-6 (37.5%) and 0-3 (44.1%) (p-for-trend=0.001). A model that included gait speed <0.46 meter/second (OR, 2.7; 95% CI, 1.2-6.4), chair stands time ≥11.2 seconds (OR, 3.5; 95% CI, 1.0-12.4), MMSE <24 points (OR, 2.9; 95% CI, 1.3-6.4), isolated SAVR (OR, 5.4; 95% CI, 2.1-13.8), and SAVR and coronary artery bypass grafting (OR, 15.8; 95% CI, 5.5-45.7) predicted delirium better than the existing prediction rule (C statistics: 0.71 vs 0.61; p=0.035).

Conclusion

Assessing physical performance, in addition to cognitive function, can help identify high-risk patients for delirium after SAVR and TAVR.

Volumetric Carotid Flow Characteristics in Doppler Ultrasonography in Healthy Population Over 65 Years Old

Background: Carotid flow velocity criteria are well established, with age being a factor influencing measurements. However, there are no volumetric standards for the flow in extracranial arteries. The aim of the study was related to volumetric flow assessment of extracranial arteries in a healthy population >65 years old. Methods: Doppler volumetric measurements of internal carotid (ICA), external carotid (ECA) and vertebral arteries (VA) were performed in 123 healthy volunteers >65 years old and compared with 56 healthy volunteers <65 years old. Results: The continuous decline in cerebral blood flow (CBF) volume was observed (p < 0.00001). Volumetric reference values were established in study groups: 1., 65–69 years: 898.5 ± 119.1; 2., 70–74 years: 838.5 ± 148.9; 3., 75–79 years: 805.1 ± 99.3; 4., >80 years: 685.7 ± 112.3 (mL/min). Significant differences were observed between groups: 1 and 3.4, as well as 3 and 4 (p = 0.0295, < 0.000001, 0.00446 respectively). CBF volume decreases gradually with age: 28–64 years—6.2 mL/year (p = 0.0019), 65–75 years—11.4 mL/year (p = 0.0121) and >75 years—14.3 mL/year (p = 0.0074). This is a consequence of flow volume decline in ICA (p = 0.00001) and to lesser extent ECA (p = 0.0011). The decrease of peak systolic (p = 0.002) and end diastolic (p = < 0.00001) velocities in ICA and peak systolic velocity in ECA (p = 0.0017) were observed. Conclusions: CBF decreases with ageing. Volumetric assessment of CBF may play an important additional role in diagnostics of patients with carotid stenosis. Doppler assessment of cerebral flow volume may create an interesting tool for identifying patients with diminished cerebrovascular reserve and higher risk of ischemic symptoms occurrence.

Falls and Cancer

Falls among older people are common and are associated with substantial morbidity, mortality and healthcare costs. Increasingly cancer is becoming a disease of older people and fall rates are higher in elders living with cancer. Cancer and its treatments potentiate important risk factors for falls, including muscle weakness, poor balance, proprioception, cognitive impairment and functional disability. Sarcopenia refers to the progressive deterioration in muscle strength, mass and quality with ageing. Chronic conditions and cancer amplify this decline and are associated with a greater negative effect on function. Age-related impairments of lower limb neurological function are commonly exacerbated by neurotoxic chemotherapy, resulting in gait and balance deficits. Postural instability and falls erode confidence and result in a negative cycle of diminishing activity levels, further deconditioning and a higher risk of further falls. Cancer-related fatigue, sleep and mood disturbances compound this progressive frailty, further worsening treatment tolerance and outcomes. Cognitive impairment is a potent risk factor for falling and is frequently associated with gait abnormalities. The well-recognised effects of cancer treatment on working memory, attention, processing speed and executive function are often apparent (when their presence is sought) before treatment and may be as much the result of the cancer itself as they are 'chemo brain'. Structured exercise programmes focusing on progressively challenging strength and balance training are of proven benefit in falls prevention. Regular aerobic exercise accrues additional benefits in improved cardiorespiratory resilience and concomitant positive effects on treatment tolerance. Increased activity levels positively influence cognition, mood and foster an improved sense of well-being. Simple, practicable clinic-based tests of physical functioning, cognition and neurological function can help to identify those at high risk of falls and functional decline. The use of such instruments can aid judicious treatment planning and identify those most likely to benefit from more detailed specialist comprehensive geriatric assessment.

White matter hyperintensity load on stroke recurrence and mortality at 1 year after ischemic stroke

Objective

To define the role and risks associated with white matter hyperintensity (WMH) load in a stroke population with respect to recurrent stroke and mortality after ischemic stroke.

Methods

A total of 7,101 patients at a network of university hospitals presenting with ischemic strokes were followed up for 1 year. Multivariable Cox proportional hazards model and competing risk analysis were used to examine the independent association between quartiles of WMH load and stroke recurrence and mortality at 1 year.

Results

Overall recurrent stroke risk at 1 year was 6.7%/y, divided between 5.6%/y for recurrent ischemic and 0.5%/y for recurrent hemorrhagic strokes. There was a stronger association between WMH volume and recurrent hemorrhagic stroke by quartile (hazard ratio [HR] 7.32, 14.12, and 33.52, respectively) than for ischemic recurrence (HR 1.03, 1.37, and 1.61, respectively), but the absolute incidence of ischemic recurrence by quartile was higher (3.8%/y, 4.5%/y, 6.3%/y, and 8.2%/y by quartiles) vs hemorrhagic recurrence (0.1%/y, 0.4%/y, 0.6%/y, and 1.3%/y). All-cause mortality (10.5%) showed a marked association with WMH volume (HR 1.06, 1.46, and 1.60), but this was attributable to nonvascular rather than vascular causes.

Conclusions

There is an association between WMH volume load and stroke recurrence, and this association is stronger for hemorrhagic than for ischemic stroke, although the absolute risk of ischemic recurrence remains higher. These data should be helpful to practitioners seeking to find the optimal preventive/treatment regimen for poststroke patients and to individualize risk-benefit ratios.

Characterizing a perfusion-based periventricular small vessel region of interest

The periventricular white matter (PVWM) is supplied by terminal distributions of small vessels and is particularly susceptible to developing white matter lesions (WML) associated with cerebral small vessel disease (CSVD). We obtained group-averaged cerebral blood flow (CBF) maps from Arterial Spin Labeled (ASL) perfusion MRI data obtained in 436 middle-aged (50.4 ± 3.5 years) subjects in the NHLBI CARDIA study and in 61 elderly (73.3 ± 6.9 years) cognitively normal subjects recruited from the Penn Alzheimer's Disease Center (ADC) and found that the lowest perfused brain voxels are located within the PVWM. We constructed a white matter periventricular small vessel (PSV) region of interest (ROI) by empirically thresholding the group averaged CARDIA CBF map at CBF < 15 ml/100 g/min. Thereafter we compared CBF in the PSV ROI and in the remaining white matter (RWM) with the location and volume of WML measured with Fluid Attenuated Inversion Recovery (FLAIR) MRI. WM CBF was lower within WML than outside WML voxels (p < <0.0001) in both the PSV and RWM ROIs, however this difference was much smaller (p < <0.0001) in the PSV ROI than in the RWM suggesting a more homogenous reduction of CBF in the PSV region. Normalized WML volumes were significantly higher in the PSV ROI than in the RWM and in the elderly cohort as compared to the middle-aged cohort (p < <0.0001). Additionally, the PSV ROI showed a significantly (p = .001) greater increase in lesion volume than the RWM in the elderly ADC cohort than the younger CARDIA cohort. Considerable intersubject variability in PSV CBF observed in both study cohorts likely represents biological variability that may be predictive of future WML and/or cognitive decline. In conclusion, a data-driven PSV ROI defined by voxels with low perfusion in middle age defines a region with homogeneously reduced CBF that is particularly susceptible to progressive ischemic injury in elderly controls. PSV CBF may provide a mechanistically specific biomarker of CSVD.

Relevance of brain lesion location for cognition in vascular mild cognitive impairment

Background

Vascular mild cognitive impairment (VMCI) is a potentially transitional state between normal aging and vascular dementia. The presence of macroscopic white matter lesions (WML) of moderate or severe extension on brain MRI is the hallmark of the VMCI.

Objective

To assess the clinical relevance of the frequency of WML in patients with VMCI independently of total lesion volume (LV).

Methods

In this multicenter study, we included 110 patients with VMCI (age: 74.3 ± 6.6 years; sex: 60 women). Cognitive assessment was performed with the VMCI-Tuscany Neuropsychological Battery, which allowed to identify four VMCI groups: amnestic single (n = 9) and multi-domain (n = 76), non-amnestic single- (n = 10) and multi-domain (n = 15). Distribution and frequency of WML on MRI FLAIR images were evaluated with lesion probability map (LPM). Voxelwise statistics was performed with nonparametric permutation tests, controlling for age, sex, slice thickness, center, magnetic field strength, total LV and head size (p < .01, family-wise error-corrected for multiple comparisons across space).

Results

LPM of the WML had a fairly symmetric and widespread distribution across brain. A higher frequency of WML along association tracts of the WM such as inferior longitudinal fascicle, inferior fronto-occipital fascicle and superior longitudinal fascicle, was correlated with worst cognitive scores at the Trail Making Test Part A and Copy of the Rey–Osterrieth Complex Figure. The non-amnestic groups showed a higher frequency of WML in the anterior cingulum and superior longitudinal fascicle close to the frontal gyrus.

Conclusions

Our study showed that in patients with VMCI, independently of total LV, the higher frequency of lesions along association tracts of the WM, which mediate intrahemispheric long-range connectivity, is related with psychomotor speed and constructional praxis. Moreover, a prevalence of lesions in the frontal WM seems to characterize VMCI patients with involvement of non-amnestic domains.

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Vascular mild cognitive impairment (VMCI) has moderate-to-severe white matter lesions (WML).

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110 VMCI patients were assessed by a full neuropsychological battery and a lesion mapping approach on MRI images.

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Higher WML frequency along association tracts correlated with worst psychomotor speed and constructional praxis.

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Non-amnestic groups of VMCI had higher WML frequency in the frontal WM.

Severity of White Matter Hyperintensities and Effects on All-Cause Mortality in the Mayo Clinic Florida Familial Cerebrovascular Diseases Registry

OBJECTIVE

To compare all-cause mortality rates across the severity range of white matter hyperintensities (WMH).

PATIENTS AND METHODS

Between October 26, 2010, and October 5, 2017, the ongoing Mayo Clinic Florida Familial Cerebrovascular Diseases Registry prospectively enrolled 1011 diverse participants with and without cerebrovascular disease. T2-weighted magnetic resonance imaging of the brain was used to evaluate WMH in 455 participants using the Fazekas scale. Fazekas deep WMH (FD) and periventricular WMH (FPV) scores (0-3 points) were assigned on the basis of WMH severity. Kaplan-Meier survival analyses, Cox proportional hazards models, and estimated hazard ratios compared survival rates across FD and FPV categories. The Fisher exact and χ² tests evaluated the relationship of categorical variables, and the Kruskal-Wallis test measured the relationship of continuous variables across FD and FPV categories. All tests were performed at a P<.05 significance level.

RESULTS

Over a median follow-up of 3.06 years (range, 0.00-6.96 years), 96 deaths occurred. Higher FD scores corresponded to a higher likelihood of mortality (P<.001). Participants with an FD score of 3 were 4.69 (95% CI, 2.60-8.46) times more likely to die compared with those with an FD score of 0. Participants with higher FPV scores had a higher likelihood of mortality (P<.001). Participants with an FPV score of 3 were 7.04 (95% CI, 3.39-14.62) times more likely to die compared with those with an FPV score of 0. Once adjusted, age and baseline functional status explained most of the survival differences among the FD scores.

CONCLUSION

Associations between all-cause mortality rates across the severity range of WMH were observed in the Registry. Further studies are warranted to understand the clinical importance of WMH in other clinical populations.

Neuroimaging of Small Vessel Disease in Late-Life Depression

Cerebral small vessel disease is associated with late-life depression, cognitive impairment, executive dysfunction, distress, and loss of life for older adults. Late-life depression is becoming a substantial public health burden, and a considerable number of older adults presenting to primary care have significant clinical depression. Even though white matter hyperintensities are linked with small vessel disease, white matter hyperintensities are nonspecific to small vessel disease and can co-occur with other brain diseases. Advanced neuroimaging techniques at the ultrahigh field magnetic resonance imaging are enabling improved characterization, identification of cerebral small vessel disease and are elucidating some of the mechanisms that associate small vessel disease with late-life depression.

MRI-based evaluation of structural degeneration in the ageing brain: Pathophysiology and assessment

Advances in MRI technology have significantly contributed to our ability to understand the process of brain ageing, allowing us to track and assess changes that occur during normal ageing and neurological conditions. This paper focuses on reviewing structural changes of the ageing brain that are commonly seen using MRI, summarizing the pathophysiology, prevalence, and neuroanatomical distribution of changes including atrophy, lacunes, white matter lesions, and dilated perivascular spaces. We also review the clinically accessible methodology for assessing these MRI-based changes, covering visual rating scales, as well computer-aided and fully automated methods. Subsequently, we consider novel assessment methods designed to evaluate changes across the whole brain, and finally discuss new directions in this field of research.

Compromised prefrontal structure and function are associated with slower walking in older adults

Our previous work demonstrates that reduced activation of the executive network is associated with slow walking speed in a cohort of older adults from the MOBILIZE Boston Study. However, the influence of underlying white matter integrity on the activation of this network and walking speed is unknown. Thus, we used diffusion-weighted imaging and fMRI during an n-back task to assess associations between executive network structure, function, and walking speed. Whole-brain tract-based spatial statistics (TBSS) were used to identify regions of white matter microstructural integrity that were associated with walking speed. The integrity of these regions was then entered into multiple regression models to predict task performance and executive network activation during the n-back task. Among the significant associations of FA with walking speed, we observed the anterior thalamic radiation and superior longitudinal fasciculus were further associated with both n-back response speed and executive network activation. These findings suggest that subtle damage to frontal white matter may contribute to altered executive network activation and slower walking in older adults.

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Older adult walking speed was not associated with white matter lesion burden.

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Walking speed was associated with microstructural white matter integrity.

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The integrity of prefrontal areas was associated with executive network activation.

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Low executive network activation also corresponded to slower walking.

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Interventions targeting the executive network may preserve older adult mobility.

A population neuroscience approach to the study of cerebral small vessel disease in midlife and late life: an invited review

Aging in later life engenders numerous changes to the cerebral microvasculature. Such changes can remain clinically silent but are associated with greater risk for negative health outcomes over time. Knowledge is limited about the pathogenesis, prevention, and treatment of potentially detrimental changes in the cerebral microvasculature that occur with advancing age. In this review, we summarize literature on aging of the cerebral microvasculature, and we propose a conceptual framework to fill existing research gaps and advance future work on this heterogeneous phenomenon. We propose that the major gaps in this area are attributable to an incomplete characterization of cerebrovascular pathology, the populations being studied, and the temporality of exposure to risk factors. Specifically, currently available measures of age-related cerebral microvasculature changes are indirect, primarily related to parenchymal damage rather than direct quantification of small vessel damage, limiting the understanding of cerebral small vessel disease (cSVD) itself. Moreover, studies seldom account for variability in the health-related conditions or interactions with risk factors, which are likely determinants of cSVD pathogenesis. Finally, study designs are predominantly cross-sectional and/or have relied on single time point measures, leaving no clear evidence of time trajectories of risk factors or of change in cerebral microvasculature. We argue that more resources should be invested in 1) developing methodological approaches and basic science models to better understand the pathogenic and etiological nature of age-related brain microvascular diseases and 2) implementing state-of-the-science population study designs that account for the temporal evolution of cerebral microvascular changes in diverse populations across the lifespan.

Dietary Sodium/Potassium Intake Does Not Affect Cognitive Function or Brain Imaging Indices

BACKGROUND

Dietary sodium may influence cognitive function through its effects on cerebrovascular function and cerebral blood flow.

METHODS

The aim of this study was to evaluate the association of dietary sodium intake with cognitive decline in community-dwelling older adults. We also evaluated the associations of dietary potassium and sodium:potassium intake with cognitive decline, and associations of these nutrients with micro- and macro-structural brain magnetic resonance imaging (MRI) indices. In all, 1,194 participants in the Health Aging and Body Composition study with measurements of dietary sodium intake (food frequency questionnaire [FFQ]) and change in the modified Mini Mental State Exam (3MS) were included.

RESULTS

The age of participants was 74 ± 3 years with a mean dietary sodium intake of 2,677 ± 1,060 mg/day. During follow-up (6.9 ± 0.1 years), 340 (28%) had a clinically significant decline in 3MS score (≥1.5 SD of mean decline). After adjustment, dietary sodium intake was not associated with odds of cognitive decline (OR 0.96, 95% CI 0.50-1.84 per doubling of sodium). Similarly, potassium was not associated with cognitive decline; however, higher sodium:potassium intake was associated with increased odds of cognitive decline (OR 2.02 [95% CI 1.01-4.03] per unit increase). Neither sodium or potassium alone nor sodium:potassium were associated with micro- or macro-structural brain MRI indices. These results are limited by the use of FFQ.

CONCLUSIONS

In community-dwelling older adults, higher sodium:potassium, but not sodium or potassium intake alone, was associated with decline in cognitive function, with no associations observed with micro- and macro-structural brain MRI indices. These findings do not support reduction dietary sodium/increased potassium intake to prevent cognitive decline with aging.

The Impact of Aerobic Exercise on Fronto-Parietal Network Connectivity and Its Relation to Mobility: An Exploratory Analysis of a 6-Month Randomized Controlled Trial

Impaired mobility is a major concern for older adults and has significant consequences. While the widely accepted belief is that improved physical function underlies the effectiveness of targeted exercise training in improving mobility and reducing falls, recent evidence suggests cognitive and neural benefits gained through exercise may also play an important role in promoting mobility. However, the underlying neural mechanisms of this relationship are currently unclear. Thus, we hypothesize that 6 months of progressive aerobic exercise training would alter frontoparietal network (FPN) connectivity during a motor task among older adults with mild subcortical ischemic vascular cognitive impairment (SIVCI)—and exercise-induced changes in FPN connectivity would correlate with changes in mobility. We focused on the FPN as it is involved in top-down attentional control as well as motor planning and motor execution. Participants were randomized either to usual-care (CON), which included monthly educational materials about VCI and healthy diet; or thrice-weekly aerobic training (AT), which was walking outdoors with progressive intensity. Functional magnetic resonance imaging was acquired at baseline and trial completion, where the participants were instructed to perform bilateral finger tapping task. At trial completion, compared with AT, CON showed significantly increased FPN connectivity strength during right finger tapping (p < 0.05). Across the participants, reduced FPN connectivity was associated with greater cardiovascular capacity (p = 0.05). In the AT group, reduced FPN connectivity was significantly associated with improved mobility performance, as measured by the Timed-Up-and-Go test (r = 0.67, p = 0.02). These results suggest progressive AT may improve mobility in older adults with SIVCI via maintaining intra-network connectivity of the FPN.

Aging with Cerebral Small Vessel Disease and Dizziness: The Importance of Undiagnosed Peripheral Vestibular Disorders

Recent studies showed a link between cerebral small vessel white matter disease (SVD) and dizziness: patients whose dizziness cannot be explained by vestibular disease show severe SVD and gait abnormalities; however, little is still known about how SVD can cause this symptom. The primary aim of this study is to examine the possible underlying causes of dizziness in neurovascular patients; this is in order to assess whether treatable causes could be routinely disregarded. A secondary aim is to possibly define a central oculomotor pattern induced per se by SVD. This could help the diagnosis of SVD-related dizziness. In this single-blind prospective study, 60 patients referred to a neurovascular clinic because of dizziness and SVD on imaging were divided into an L-SVD and a H-SVD group (low and high SVD burden, respectively), and then blindly examined with vestibulometric tests. In H-SVD group, the percentage of unexplained dizziness reached 82.8%. There was a higher prevalence of peripheral vestibular abnormalities in the L-SVD patient group (51.6%) than in the H-SVD (17.2%; p = 0.012). We found no differences in central oculomotor findings between the two groups. Although oculomotricity does not show any consistent pattern, a severe SVD can directly represent a cause of dizziness. However, a patient with mild SVD is more likely to suffer by a peripheral vestibular disorder. Therefore, given the high incidence of vestibular disease in neurovascular or geriatric clinics, clinicians should be cautious when ascribing dizziness solely to the presence of SVD as easily treatable peripheral vestibular causes may be missed.

The association between lower urinary tract symptoms and falls: Forming a theoretical model for a research agenda

BACKGROUND

There is a well-recognised association between falls and lower urinary tract symptoms (LUTS) in older adults, with estimates of odd ratios for falls in the presence of LUTS ranging between 1.5 and 2.3. Falls and LUTS are both highly prevalent among older people and both are markers of frailty, with significant associated morbidity, mortality, and healthcare resource cost. This association is not well examined or explained in the literature.

AIMS

We aimed to outline current knowledge of the association between falls and lower urinary tract symptoms and suggest a research program to further investigate this.

MATERIALS AND METHODS

A consensus conference of experts in the field was convened to review the current literature and brainstorm potential future investigative avenues.

RESULTS AND DISCUSSION

Despite the recognition of this association, there has been little research to examine its potential causes, and no intervention trial has established if reducing LUTS or urinary incontinence can reduce the risk of falls. The commonly held assumption that urgency causes falls through rushing to the toilet is likely incorrect. Falls and LUTS are both symptoms of frailty and have many common causes. Gait, balance, and continence are all processes requiring cognitive input, and the concept of dual tasking may be a further link.

CONCLUSION

The significant association between lower urinary tract symptoms and falls is currently unexplained, and further research into the potential causes of this association is needed.

Executive functioning independently predicts self-rated health and improvement in self-rated health over time among community-dwelling older adults

OBJECTIVES

Self-rated health, as distinct from objective measures of health, is a clinically informative metric among older adults. The purpose of our study was to examine the cognitive and psychosocial factors associated with self-rated health.

METHODS

624 participants over the age of 60 were assessed at baseline, and of these, 510 were contacted for a follow-up two years later. Measures of executive function and self-rated health were assessed at baseline, and self-rated health was assessed at follow-up. We employed multiple linear regression analyses to investigate the relationship between executive functioning and self-rated health, while controlling for demographic, psychosocial and biological variables.

RESULTS

Controlling for other relevant variables, executive functioning independently and solely predicted self-rated health, both at a cross-sectional level, and also over time. Loneliness was also found to cross-sectionally predict self-rated health, although this relationship was not present at a longitudinal level.

CONCLUSION

Older adults' self-rated health may be related to their executive functioning and to their loneliness. Self-rated health appeared to improve over time, and the extent of this improvement was also related to executive functioning at baseline. Self-rated health may be a judgement made of one's functioning, especially executive functioning, which changes with age and therefore may be particularly salient in the reflections of older adults.

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.

Digit Symbol Substitution test and future clinical and subclinical disorders of cognition, mobility and mood in older adults

OBJECTIVE

to examine whether psychomotor speed predicts individual and combined disorders in cognition, mobility and mood and if white matter hyperintensities explain these associations.

DESIGN AND SETTING

longitudinal; Cardiovascular Health Study.

SUBJECTS

5,888 participants (57.6% women, 15.7% black, 75.1 (5.5), mean years (SD)).

METHODS

psychomotor speed (Digit Symbol Substitution Test (DSST)) and small vessel disease (white matter hyperintensities (WMH)) were measured in 1992-94. Global cognition (Modified Mini-Mental State (3MS) examination), mobility (gait speed (GS)) and mood (Center for Epidemiologic Studies Depression (CES-D) scale) were measured annually over 5 years and classified as clinical, subclinical or no disorders based on established values (3MS: 80 and 85 points; GS: 0.6 and 1.0 m/s; CES-D: 10 and 5 points). Analyses were adjusted for demographics, baseline status, education, diabetes, hypertension, ankle-arm index.

RESULTS

among those with no disorder in cognition, mobility and mood (N = 619) in 1992-94, being in the lowest DSST quartile compared to the highest was associated with nearly twice the odds of developing 1+ clinical or subclinical disorders (N = 413) during follow-up. Associations were stronger for incident clinical disorders in cognition (OR: 8.44, p < 0.01) or mobility (OR: 9.09, p < 0.05) than for mood (OR: 1.88, p < 0.10). Results were similar after adjustment for WMH.

CONCLUSIONS

slower psychomotor speed may serve as a biomarker of risk of clinical disorders of cognition, mobility and mood. While in part attributable to vascular brain disease, other potentially modifiable contributors may be present. Further studying the causes of psychomotor slowing with ageing might provide novel insights into age-related brain disorders.

Cerebral White Matter and Slow Gait: Contribution of Hyperintensities and Normal-appearing Parenchyma

BACKGROUND

White matter hyperintensities (WMH), a common marker of cerebral small vessel disease, and lower microstructural integrity of normal-appearing white matter are associated with slower gait. How these cerebral measures interact in relation to slower gait is unknown. We assessed whether microstructural integrity of normal-appearing white matter, measured by fractional anisotropy (FA), moderates the association of higher WMH with slower gait.

METHODS

WMH, FA, and gait speed were acquired for 265 community-dwelling older adults (average age = 82.9 years).

RESULTS

The inverse association between WMH and gait was robust to adjustment for age, gender, muscle strength, obesity, stroke, and hypertension (fully adjusted model: βs = -0.19, p = .001). The interaction between WMH and FA was significant; analyses stratified by FA showed that the inverse association between WMH and gait speed was significant only for those with low FA (FA < median, fully adjusted model: βs = -0.28, p = .001). Voxel-based results were similar for participants with FA less than median, there was an inverse association between gait speed and WMH which extended throughout the white matter (genu and body of corpus callosum, anterior limb of internal capsule, corona radiata, and superior longitudinal and fronto-occipital fasciculus). In contrast, for participants with FA ≥ median, the association was limited to the genu of corpus callosum, the cingulum, and the inferior longitudinal fasciculus.

CONCLUSIONS

Microstructural integrity is a moderating factor in the association between WMH and gait. Future studies should examine whether higher microstructural integrity represents a source of compensation in those with greater WMH burden to maintain function in late life.

Severity of White Matter Hyperintensities and Length of Hospital Stay in Patients with Cognitive Impairment: A CREDOS (Clinical Research Center for Dementia of South Korea) Study

BACKGROUND & OBJECTIVE

White matter hyperintensities (WMHs) contribute to aggravation of dementia or geriatric syndrome, thereby resulting in functional impairment. However, evidence of direct association between WMHs and medical resource utilization indicated by length of hospital stay (LOS) is scarce in patients with cognitive impairment. This study aimed to examine the relationship between the severity of WMHs and LOS in patients with cognitive impairment.

METHODS

4,253 older adults with cognitive impairment were enrolled in this study. We defined LOS as the total sum of days from January 1, 2008 to December 31, 2012. The severity of periventricular (PVWMHs), deep (DWMHs), and overall white matter hyperintensities (Overall WMHs) was evaluated by a visual rating scale. We conducted multinomial logistic regression to demonstrate the relationship between LOS and severity of PVWHMs, DWHMs, and Overall WMHs, respectively.

RESULTS

The median LOS was 20 days. Severe PVWMHs had a higher likelihood of longer LOS (Q3: odd ratio/OR = 1.32, 95% confidence interval/CI = 1.06-1.64; Q4: OR = 1.33, 95% CI = 1.07-1.65; Q5: OR = 1.55, 95% CI = 1.26-1.91). As for DWMHs, moderate DWMHs were related to longer LOS (Q4: OR = 1.33, 95% CI = 1.03-1.71; Q5: OR = 1.63, 95% CI = 1.26-2.11). Finally, severity of overall WMHs was independently associated with LOS, which was similar to the results of DWMHs.

CONCLUSION

These findings would advocate for prevention of WMHs to stave off excess medical resource utilization in patients with cognitive impairment.

Neighborhood Socioeconomic Status and Cognitive Function in Late Life

Neighborhood socioeconomic status (NSES) is associated with cognitive function, independently of individual demographic, health, and socioeconomic characteristics. However, research has been largely cross-sectional, and mechanisms of the association are unknown. In 1992-1993, Cardiovascular Health Study participants (n = 3,595; mean age = 74.8 years; 15.7% black) underwent cognitive testing and magnetic resonance imaging of white matter hyperintensities (WMH), and their addresses were geocoded. NSES was calculated using 1990 US Census data (block groups; 6 measures of wealth, education, and occupation). The Modified Mini-Mental State Examination (3MS) was used to assess general cognition, and the Digit Symbol Substitution Test (DSST) was used to assess speed of processing annually for 6 years. Associations of race-specific NSES tertiles with 3MS, DSST, and WMH were estimated using linear mixed-effects models accounting for geographic clustering, stratified by race, and adjusted for demographic, health, and individual socioeconomic status (education, income, lifetime occupational status) variables. In fully adjusted models, higher NSES was associated with higher 3MS scores in blacks (mean difference between highest and lowest NSES = 2.4 points; P = 0.004) and whites (mean difference = 0.7 points; P = 0.02) at baseline but not with changes in 3MS over time. NSES was marginally associated with DSST and was not associated with WMH. Adjustment for WMH did not attenuate NSES-3MS associations. Associations of NSES with cognition in late adulthood differ by race, are not explained by WMH, and are evident only at baseline.

Executive dysfunction is associated with poorer health-related quality of life in pediatric brain tumor survivors

Children with a brain tumor (BT) are at risk for a number of physical and cognitive problems that may lower their health-related quality of life (HRQoL). Executive functioning (EF) and intellectual ability are hypothesized to associate with HRQoL and deficits in these areas may be amenable to interventions. This study aimed to investigate intellectual function, EF, and HRQoL following conformal radiation therapy (CRT) for pediatric BT. Forty-five BT survivors (age 12.68 ± 2.56) treated with CRT participated. Thirty-six siblings of BT patients (age 12.36 ± 2.13) and 33 survivors of non-CNS solid tumors (ST; age 12.18 ± 2.88) were comparison groups. IQ estimate (Wechsler Abbreviated Scale of Intelligence; WASI), EF ratings (Behavior Rating Inventory of Executive Function; BRIEF), and HRQoL ratings (KINDL-R) were obtained. BT survivors reported lower overall HRQoL than ST survivors (p = .012). Parents reported lower overall HRQoL for BT survivors than siblings (p = .014). Parent-report on individual areas of HRQoL was higher than self-report for most subscales. IQ and HRQoL ratings were not related (Parent r = .17, p = .27; Child r = .11, p = .49). EF ratings correlated with Parent (r = -.15 to -.73) but not Child HRQoL ratings. Children with BT experienced poorer HRQoL than controls. Children's HRQoL was consistently rated higher by parent- than self-report across all domains. HRQoL was associated with EF, but not with IQ. These findings identify interventions targeting EF (e.g., cognitive rehabilitation, medication) as a possible avenue for improving HRQoL in childhood BT survivors.

Plasma tPA-Activity and Progression of Cerebral White Matter Hyperintensities in Lacunar Stroke Patients

Introduction

Tissue plasminogen activator (tPA)-activity and plasminogen activator inhibitor type 1 (PAI-1) antigen are considered to be haemostasis-related markers of endothelial activation and relate to presence of cerebral white matter hyperintensities (WMH) as was earlier shown in a cross-sectional study. We investigated whether tPA-activity and PAI-1 levels are associated with WMH progression in a longitudinal study.

Methods

In 127 first-ever lacunar stroke patients in whom baseline brain MRI and plasma levels of tPA-activity and PAI-1-antigen were available, we obtained a 2-year follow-up MRI. We assessed WMH progression by a visual WMH change scale. We determined the relationship between levels of tPA-activity and PAI-1 and WMH progression, by logistic regression analysis.

Results

Plasma tPA-activity was associated with periventricular WMH progression (OR 2.36, 95% CI 1.01–5.49, with correction for age and sex and baseline presence of WMH), but not with deep or any (periventricular and/or deep) WMH progression. PAI-1 levels were lower in patients with WMH progression, but these results were not significant.

Conclusion

We found a relationship between plasma tPA-activity and progression of periventricular WMH. More research is needed to determine whether there is a (direct) role of tPA in the development and progression of WMH.

A combined measure of vascular risk for white matter lesions

BACKGROUND

Though hypertension is a commonly studied risk factor for white matter lesions (WMLs), measures of blood pressure may fluctuate depending on external conditions resulting in measurement error. Indicators of arterial stiffening and reduced elasticity may be more sensitive indicators of risk for WMLs in aging; however the interdependent nature of vascular indicators creates statistical complications.

OBJECTIVE

The purpose of the study was to determine whether a factor score comprised of multiple vascular indicators would be a stronger predictor of WMLs than traditional measures of blood pressure.

METHODS

In a sample of well-characterized nondemented older adults, we used a factor analytic approach to account for variance common across multiple vascular measures while reducing measurement error. The result was a single factor score reflecting arterial stiffness and reduced elasticity. We used this factor score to predict white matter lesion volumes acquired via fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging.

RESULTS

The combined vascular factor score was a stronger predictor of deep WML (β = 0.42, p < 0.001) and periventricular WML volumes (β = 0.49, p < 0.001). After accounting for the vascular factor, systolic and diastolic blood pressure measurements were not significant predictors.

CONCLUSIONS

This suggests that a combined measure of arterial elasticity and stiffening may be a stronger predictor of WMLs than systolic and diastolic blood pressure accounting for the multicollinearity associated with a variety of interrelated vascular measures.

Continence Across Continents To Upend Stigma and Dependency (CACTUS-D): study protocol for a cluster randomized controlled trial

Background

Urinary incontinence occurs in 40 % of women aged 65 years and over; however, only 15 % seek care and many delay healthcare seeking for years. Incontinence is associated with depression, social isolation, reduced quality of life, falls and other comorbidities. It is accompanied by an enormous cost to the individual and society. Despite the substantial implications of urinary incontinence on social, psychological and physical well-being of older women, the impact of continence promotion on urinary symptom improvement and subsequent effects on falls, quality of life, stigma, social participation and the cost of care remains unknown.

Methods

This study is a mixed methods multi-national open-label 2-arm parallel cluster randomized controlled trial aiming to recruit 1000 community-dwelling incontinent women aged 65 years and older across Quebec, Western Canada, France and United Kingdom. Participants will be recruited through community organizations. Data will be collected at 6 time points: baseline and 1 week, 3 months, 6 months, 9 months and 12 months after baseline. One of the primary objectives is to evaluate whether the continence promotion intervention improves incontinence symptoms (measured with the Patient Global Impression of Improvement questionnaire, PGI-I) at 12 months post intervention compared to the control group. Other co-primary outcomes include changes in incontinence-related stigma, fall reduction, and incremental cost-effectiveness ratio and quality-adjusted life years. Data analysis will account for correlation of outcomes (clustering) within community organizations. A qualitative sub-study will explore stigma reduction.

Discussion

Community-based continence promotion programs may be a cost-effective strategy to reduce urinary incontinence, stigma and falls among older women with untreated incontinence, and simultaneously improve quality of life and healthy active life expectancy.

Trial registration

ClinicalTrials.gov: NCT01858493, registered 13 May 2013

Intra-individual lap time variation of the 400-m walk, an early mobility indicator of executive function decline in high-functioning older adults?

Higher intra-individual lap time variation (LTV) of the 400-m walk is cross-sectionally associated with poorer attention in older adults. Whether higher LTV predicts decline in executive function and whether the relationship is accounted for by slower walking remain unanswered. The main objective of this study was to examine the relationship between baseline LTV and longitudinal change in executive function. We used data from 347 participants aged 60 years and older (50.7% female) from the Baltimore Longitudinal Study of Aging. Longitudinal assessments of executive function were conducted between 2007 and 2013, including attention (Trails A, Digit Span Forward Test), cognitive flexibility and set shifting (Trails B, Delta TMT: Trials B minus Trials A), visuoperceptual speed (Digit Symbol Substitution Test), and working memory (Digit Span Backward Test). LTV and mean lap time (MLT) were obtained from the 400-m walk test concurrent with the baseline executive function assessment. LTV was computed as variability of lap time across ten 40-m laps based on individual trajectories. A linear mixed-effects model was used to examine LTV in relation to changes in executive function, adjusted for age, sex, education, and MLT. Higher LTV was associated with greater decline in performance on Trails B (β = 4.322, p < 0.001) and delta TMT (β = 4.230, p < 0.001), independent of covariates. Findings remained largely unchanged after further adjustment for MLT. LTV was not associated with changes in other executive function measures (all p > 0.05). In high-functioning older adults, higher LTV in the 400-m walk predicts executive function decline involving cognitive flexibility and set shifting over a long period of time. High LTV may be an early indicator of executive function decline independent of MLT.

The contribution of white matter lesions to Parkinson's disease motor and gait symptoms: a critical review of the literature

White matter lesions (WML) associated with cerebrovascular disease (CVD) may be observed on magnetic resonance imaging in Parkinson's disease (PD) patients. WML are an important factor contributing to postural, gait, and cognitive impairment in the elderly without PD and worsening the course of Alzheimer's disease (AD). Numerous articles are available on this topic. Whether WML modify and negatively influence the clinical symptoms, and course of PD is a subject of debate. The aim of this review is to examine the available literature on the contribution of WML to PD motor symptoms in relation to clinical characteristics and methods of assessing WML on MRI. After reviewing the database, we identified 19 studies reporting the relationship between WML and PD; ten studies focusing on the impact of WML on the cognitive status in PD were excluded. We analysed altogether nine studies reporting the relationship between WML and motor signs of PD. The review found association between WML severity and freezing of gait, less significant to responsiveness to dopaminergic treatment and postural instability; no negative impact on tremor and falls was observed. The impact of WML on bradykinesia and rigidity was inconsistent. Comorbid WML is associated with worsening axial motor performance, probably independently from the degree of nigrostriatal dopaminergic denervation in PD. Reducing the vascular risk factors that cause WML may be helpful in preventing the development of axial symptoms and ultimately in improving the quality of life of patients with PD. Given the lack of systematic studies, additional research in this field is needed.

Mobility and cognition are associated with wellbeing and health related quality of life among older adults: a cross-sectional analysis of the Vancouver Falls Prevention Cohort

Background

Ascertaining individuals’ quality of life and wellbeing is essential in public health and clinical research. The impact of these two pressing geriatric syndromes – impaired mobility and cognitive function -- on wellbeing and quality of life is not well examined. Hence, our objective was to identify key clinically relevant outcome measures of mobility and cognitive function that explain variation in wellbeing and health related quality of life (HRQoL) among community dwelling older adults.

Methods

We conducted a cross-sectional analysis of 229 participants presenting to the Vancouver Falls Prevention Clinic from June 2010 through October 2013. The linear regression models included two dependent variables: the ICECAP-O assessing wellbeing and the EQ-5D-3L assessing HRQoL. Key independent variables included the Short Performance Physical Battery (SPPB) and the Montreal Cognitive Assessment (MoCA). Covariates included Functional Comorbidity Index (FCI), sex and age. In the two multiple linear regression models, age was statistically controlled. Other covariates (i.e., sex and FCI) were included based on statistical significance (i.e., p < 0.05).

Results

The SPPB was significantly associated with HRQoL and with wellbeing after adjusting for known covariates (p < 0.05, Unstandardized ß (Standard Error) 0.023 (0.006) for HRQoL and 0.016 (0.003) for wellbeing). The MoCA was significantly associated with wellbeing after adjusting for known covariates (p = 0.006), Unstandardized ß (Standard Error) 0.005 (0.002) but not with health related quality of life (p > 0.05).

Conclusion

We found that a measure of mobility and balance was associated with HRQoL and wellbeing. However, cognitive function was associated with wellbeing only. This study highlights the potential importance of considering wellbeing as an outcome measure if interventions are intended to have a broader impact than health alone.

Cerebral autoregulation, beta amyloid, and white matter hyperintensities are interrelated

Emerging studies link vascular risk factors and cerebrovascular health to the prevalence and rates of progression in Alzheimer's disease (AD). The brain's ability to maintain constant blood flow across a range of cerebral perfusion pressures, or autoregulation, may both promote and result from small vessel cerebrovascular disease and AD-related amyloid pathology. Here, we examined the relationship among cerebral autoregulation, small vessel cerebrovascular disease, and amyloid deposition in 14 non-demented older adults. Reduced cerebral autoregulation, was associated with increased amyloid deposition and increased white matter hyperintensity volume, which, in turn were positively associated with each other. For the first time in humans, we demonstrate an interrelationship among AD pathology, small vessel cerebrovascular disease, and cerebral autoregulation. Vascular factors and AD pathology are not independent but rather appear to interact.

Predicting cognitive function from clinical measures of physical function and health status in older adults

INTRODUCTION

Current research suggests that the neuropathology of dementia-including brain changes leading to memory impairment and cognitive decline-is evident years before the onset of this disease. Older adults with cognitive decline have reduced functional independence and quality of life, and are at greater risk for developing dementia. Therefore, identifying biomarkers that can be easily assessed within the clinical setting and predict cognitive decline is important. Early recognition of cognitive decline could promote timely implementation of preventive strategies.

METHODS

We included 89 community-dwelling adults aged 70 years and older in our study, and collected 32 measures of physical function, health status and cognitive function at baseline. We utilized an L1-L2 regularized regression model (elastic net) to identify which of the 32 baseline measures were strongly predictive of cognitive function after one year. We built three linear regression models: 1) based on baseline cognitive function, 2) based on variables consistently selected in every cross-validation loop, and 3) a full model based on all the 32 variables. Each of these models was carefully tested with nested cross-validation.

RESULTS

Our model with the six variables consistently selected in every cross-validation loop had a mean squared prediction error of 7.47. This number was smaller than that of the full model (115.33) and the model with baseline cognitive function (7.98). Our model explained 47% of the variance in cognitive function after one year.

DISCUSSION

We built a parsimonious model based on a selected set of six physical function and health status measures strongly predictive of cognitive function after one year. In addition to reducing the complexity of the model without changing the model significantly, our model with the top variables improved the mean prediction error and R-squared. These six physical function and health status measures can be easily implemented in a clinical setting.

Longitudinal systolic blood pressure characteristics and integrity of white matter tracts in a cohort of very old black and white adults

BACKGROUND

We sought to determine which systolic blood pressure (SBP) characteristics are associated with reduced brain integrity and whether these associations are stronger for white or gray matter. We hypothesized that exposure to higher and variable SBP will be associated with lower structural integrity of both gray and white matter.

METHODS

Neuroimaging, SBP, and cognition were obtained in 311 community-dwelling adults in 2006–2008 (average age = 83 years; 58% women; 40% black). Antihypertensive medications, SBP, and health-related factors were collected from 1997 to 1998 to time of neuroimaging. SBP values obtained from 1997 to 1998 to time of neuroimaging were used to compute mean; pulse pressure; coefficient of variation; and peak, load, and group-based trajectories.

RESULTS

Higher mean SBP was associated with lower white matter integrity in uncinate and superior lateral fasciculi bilaterally, independent of age, stroke history, antihypertensive medication use (odds ratio of having white matter hyperintensities greater than or equal to the median for 10mm Hg of SBP = 10.4, 95% confidence interval = 10.2–10.6, P = 0.0001; standardized beta for fractional anisotropy = −13.54, SE = 4.58, P = 0.003). These neuroimaging markers attenuated the association between higher SBP and lower digit symbol substitution test. Results were similar for trajectories of SBP and stronger for those with previously higher and variable SBP even if SBP was normal at neuroimaging. Results were similar for those without stroke. Associations with gray matter measures were not significant.

CONCLUSIONS

If confirmed, these data suggest a history of higher and variable SBP for very old adults may be useful to alert clinicians to potential lower integrity in selected tracts, whereas cross-sectional SBP measurements may obscure the risk of underlying white matter hyperintensities. Whether lowering and/or stabilizing SBP levels in very old adults without a remarkable cardiovascular history would have neuroprotective effects and reduce dementia risk needs further study.

Pathways linking regional hyperintensities in the brain and slower gait

IMPORTANCE

Cerebral white matter hyperintensities (WMHs) are involved in the evolution of impaired mobility and executive functions. Executive functions and mobility are also associated. Thus, WMHs may impair mobility directly, by disrupting mobility-related circuits, or indirectly, by disrupting circuits responsible for executive functions. Understanding the mechanisms underlying impaired mobility in late life will increase our capacity to develop effective interventions.

OBJECTIVE

To identify regional WMHs most related to slower gait and to examine whether these regional WMHs directly impact mobility, or indirectly by executive functions.

DESIGN

Cross-sectional study. Twenty-one WMH variables (i.e., total WMH volume and WMHs in 20 tracts), gait speed, global cognition (Modified Mini-Mental State Examination; 3MS), and executive functions and processing speed (Digit-Symbol Substitution Test; DSST) were assessed. An L1-L2 regularized regression (i.e., Elastic Net model) identified the WMH variables most related to slower gait. Multivariable linear regression models quantified the association between these WMH variables and gait speed. Formal tests of mediation were also conducted.

SETTING

Community-based sample.

PARTICIPANTS

Two hundred fifty-three adults (mean age: 83years, 58% women, 41% black).

MAIN OUTCOME MEASURE

Gait speed.

RESULTS

In older adults with an average gait speed of 0.91m/sec, total WMH volume, WMHs located in the right anterior thalamic radiation (ATRR) and frontal corpuscallosum (CCF) were most associated with slower gait. There was a >10% slower gait for each standard deviation of WMH in CCF, ATRR or total brain (standardized beta in m/sec [p value]: -0.11 [p=0.046], -0.15 [p=0.007] and -0.14 [p=0.010], respectively). These associations were substantially and significantly attenuated after adjustment for DSST. This effect was stronger for WMH in CCF than for ATRR or total WMH (standardized beta in m/sec [p value]: -0.07 [p=0.190], -0.12 [p=0.024] and -0.10 [p=0.049], respectively). Adjustment for 3MS did not change these associations. The mediation analyses also found that DSST significantly mediated the associations between WMHs and gait speed. Our models were adjusted for age, sex, BMI, quadriceps strength, years of education, standing height, and prevalent hypertension.

CONCLUSION

The impact, direct or indirect, of WMHs on gait speed depended on their location and was mediated by executive function. Thus, multi-faceted interventions targeting executive control functions as well as motor functions, such as balance and strength training, are candidates to the maintenance of mobility across the lifespan.