Exploring the effects of coexisting amyloid in subcortical vascular cognitive impairment

Neuroimaging in Vascular Cognitive Impairment and Dementia: A Systematic Review

Cerebrovascular diseases are well established causes of cognitive impairment. Different etiologic entities, such as vascular dementia (VaD), vascular cognitive impairment, subcortical (ischemic) VaD, and vascular cognitive disorder, are included in the umbrella definition of vascular cognitive impairment and dementia (VCID). Because of the variability of VCID clinical presentation, there is no agreement on criteria defining the neuropathological threshold of this disorder. In fact, VCID is characterized by cerebral hemodynamic alteration which ranges from decreased cerebral blood flow to small vessels disease and involves a multifactorial process that leads to demyelination and gliosis, including blood-brain barrier disruption, hypoxia, and hypoperfusion, oxidative stress, neuroinflammation and alteration on neurovascular unit coupling, cerebral microbleeds, or superficial siderosis. Numerous criteria for the definition of VaD have been described: the National Institute of Neurological Disorders and Stroke Association Internationale pour Recherche'-et-l'Enseignement en Neurosciences criteria, the State of California Alzheimer's Disease Diagnostic and Treatment Centers criteria, DSM-V criteria, the Diagnostic Criteria for Vascular Cognitive Disorders (a VASCOG Statement), and Vascular Impairment of Cognition Classification Consensus Study. Neuroimaging is fundamental for definition and diagnosis of VCID and should be used to assess the extent, location, and type of vascular lesions. MRI is the most sensible technique, especially if used according to standardized protocols, even if CT plays an important role in several conditions. Functional neuroimaging, in particular functional MRI and PET, may facilitate differential diagnosis among different forms of dementia. This systematic review aims to explore the state of the art and future perspective of non-invasive diagnostics of VCID.

Long-term follow-up outcomes for patients undergoing primary total hip arthroplasty with uncemented versus cemented femoral components: a retrospective observational study with a 5-year minimum follow-up

BACKGROUND

This retrospective analysis compared the long-term outcomes for patients with a femoral neck fracture (AO/OTA type 31B) treated with a primary unilateral total hip arthroplasty with uncemented or cemented femoral components (UTHA or CTHA, respectively).

METHODS

We conducted a retrospective cohort study using the South China Hip Arthroplasty Database. We identified 422 patients with femoral neck fracture (AO/OTA type 31B) who were previously treated with primary unilateral UTHA or CTHA between 2007 and 2015, with follow-up until 2019. Follow-up occurred 1, 3, 6 and 12 months postoperatively and yearly thereafter. The primary outcome was the Harris hip score (HHS). The secondary outcome was the orthopaedic complication rate.

RESULTS

In total, 324 patients (UTHA n = 160, mean age 68.61 ± 7.49 years; CTHA n = 164, mean age 68.75 ± 7.04 years) were evaluated for study eligibility. The median follow-up was 73.3 months (range, 11.6-89.2 months). At the final follow-up, HHS was 74.09 ± 6.23 vs 79.01 ± 10.21 (UTHA vs CTHA, p = 0.012). Significant differences were detected in the incidence of prosthetic revision, loosening, and periprosthetic fracture between the UTHA and CTHA groups (7.5% for UTHA vs 1.8% for CTHA, p = 0.015; 17.5% for UTHA vs 8.5% for CTHA, p = 0.016; 11.9% for UTHA vs 4.9% for CTHA, p = 0.021, respectively).

CONCLUSION

In this setting, CTHA demonstrated superiority to UTHA by improving functional outcomes and decreasing complication rates.

Identifying an Optimal Cutoff of the Montreal Cognitive Assessment to Predict Amyloid-PET Positivity in a Referral Memory Clinic

BACKGROUND

Brain amyloid- positron emission tomography (PET) imaging is highly sensitive for identifying Alzheimer disease. Currently, there is a lack of insight on the association between amyloid-PET status and the widely used Montreal cognitive assessment (MoCA). Studying this relationship may optimize the clinical use of amyloid-PET imaging.

OBJECTIVES

To evaluate the relationship between amyloid-PET status and MoCA scores and to identify a MoCA score cutoff that translates to amyloid-PET positivity.

METHODS

Using retrospective chart review, patients from 2010 to 2017 with amyloid-PET scans (positive or negative) and MoCA test scores were included. We studied the relationship between amyloid-PET status and MoCA scores and the influence of age, sex, education, and race. A MoCA score cutoff for amyloid-PET positivity was estimated.

RESULTS

Among the 684 clinic patients with dementia, 99 fulfilled inclusion criteria. Amyloid-PET positivity was associated significantly with lower MoCA scores (median=19, U=847, P=0.01). The MoCA score cutoff (25) used for minimal cognitive impairment (MCI) predicted amyloid-PET positivity suboptimally (sensitivity=94.6%, specificity=13.9%). A MoCA score cutoff of 20 patients had optimal sensitivity (64.2%) and specificity (67.4%).

CONCLUSIONS

Amyloid-PET positivity is associated with lower MoCA scores. Clinical utility of amyloid-PET scan is likely to be suboptimal at the MoCA score cutoff for minimal cognitive impairment.

Associations between cerebral amyloid and changes in cognitive function and falls risk in subcortical ischemic vascular cognitive impairment

Background

To determine the association between amyloid-beta (Aβ) plaque deposition and changes in global cognition, executive functions, information processing speed, and falls risk over a 12-month period in older adults with a primary clinical diagnosis of subcortical ischemic vascular cognitive impairment (SIVCI).

Methods

This is a secondary analysis of data acquired from a subset of participants (N = 22) who were enrolled in a randomized controlled trial of aerobic exercise (NCT01027858). The subset of individuals completed an ¹¹C Pittsburgh compound B (PIB) scan. Cognitive function and falls risk were assessed at baseline, 6-months, and 12-months. Global cognition, executive functions, and information processing speed were measured using: 1) ADAS-Cog; 2) Trail Making Test; 3) Digit Span Test; 4) Stroop Test, and 5) Digit Symbol Substitution Test. Falls risk was measured using the Physiological Profile Assessment. Hierarchical multiple linear regression analyses determined the unique contribution of Aβ on changes in cognitive function and falls risk at 12-months after controlling for experimental group (i.e. aerobic exercise training or usual care control) and baseline performance. To correct for multiple comparisons, we applied the Benjamini-Hochberg procedure to obtain a false discovery rate corrected threshold using alpha = 0.05.

Results

Higher PIB retention was significantly associated with greater decrements in set shifting (Trail Making Test, adjusted R² = 35.3%, p = 0.002), attention and conflict resolution (Stroop Test, adjusted R² = 33.4%, p = 0.01), and information processing speed (Digit Symbol Substitution Test, adjusted R² = 24.4%, p = 0.001) over a 12-month period. Additionally, higher PIB retention was significantly associated with increased falls risk (Physiological Profile Assessment, adjusted R² = 49.1%, p = 0.04). PIB retention was not significantly associated with change in ADAS-Cog and Verbal Digit Span Test (p > 0.05).

Conclusions

Symptoms associated with SIVCI may be amplified by secondary Aβ pathology.

Trial registration

ClinicalTrials.gov, NCT01027858, December 7, 2009.

Towards the concept of disease-modifier in post-stroke or vascular cognitive impairment: a consensus report

BACKGROUND

Vascular cognitive impairment (VCI) is a complex spectrum encompassing post-stroke cognitive impairment (PSCI) and small vessel disease-related cognitive impairment. Despite the growing health, social, and economic burden of VCI, to date, no specific treatment is available, prompting the introduction of the concept of a disease modifier.

CONSENSUS AND SUGGESTIONS

Within this clinical spectrum, VCI and PSCI remain advancing conditions as neurodegenerative diseases with progression of both vascular and degenerative lesions accounting for cognitive decline. Disease-modifying strategies should integrate both pharmacological and non-pharmacological multimodal approaches, with pleiotropic effects targeting (1) endothelial and brain-blood barrier dysfunction; (2) neuronal death and axonal loss; (3) cerebral plasticity and compensatory mechanisms; and (4) degenerative-related protein misfolding. Moreover, pharmacological and non-pharmacological treatment in PSCI or VCI requires valid study designs clearly stating the definition of basic methodological issues, such as the instruments that should be used to measure eventual changes, the biomarker-based stratification of participants to be investigated, and statistical tests, as well as the inclusion and exclusion criteria that should be applied.

CONCLUSION

A consensus emerged to propose the development of a disease-modifying strategy in VCI and PSCI based on pleiotropic pharmacological and non-pharmacological approaches.

2015 ParaPan American Games: Autonomic Function, But Not Physical Activity, Is Associated with Vascular-Cognitive Impairment in Spinal Cord Injury

Autonomic dysfunction and diminished capacity for physical exercise are commonly implicated in the 3- to 4-fold increased risk of cerebrovascular disease after spinal cord injury (SCI). We assessed cerebrovascular function (transcranial Doppler; neurovascular coupling [NVC], and cerebral pressure-flow regulation) in elite national level wheelchair rugby players (n = 23), normally active SCI individuals (n = 12), and able-bodied controls (n = 13). Cognitive (Stroop test) and autonomic function (postural change) also were evaluated. SCI individuals demonstrated reduced posterior cerebral blood flow, as well as impaired cerebrovascular and cognitive function. Autonomic dysfunction but not physical activity was related to impaired NVC and cerebral pressure-flow regulation after SCI. Routine upper-body exercise, as utilized by elite wheelchair rugby athletes, may not elicit beneficial cerebrovascular effects. On the other hand, autonomic dysfunction needs to be considered a key culprit in cerebrovascular diseases after SCI.

The blood brain barrier in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia, affecting millions of people worldwide. One of the prominent causative factors of AD pathogenesis is cerebral vascular dysfunction, which results in diminished cerebral perfusion. Moreover, due to the loss of the protective function of the blood-brain barrier (BBB), impaired clearance of excess neurotoxic amyloid beta (Aβ) occurs, causing vascular perturbation and diminished cognitive functioning. The relationship between the prevalence of AD and vascular risk factors is complex and not fully understood. In this review we illustrate the vascular risk factors, their effects on BBB function and their contributions to the onset of AD. Additionally, we discuss the underlying factors that may lead to altered neurovascular function and/or cerebral hypoperfusion in AD.