Assessing the Predictive Validity of Simple Dementia Risk Models in Harmonized Stroke Cohorts

BACKGROUND AND PURPOSE: Stroke is associated with an increased risk of dementia. To assist in the early identification of individuals at high risk of future dementia, numerous prediction models have been developed for use in the general population. However, it is not known whether such models also provide accurate predictions among stroke patients. Therefore, the aim of this study was to determine whether existing dementia risk prediction models that were developed for use in the general population can also be applied to individuals with a history of stroke to predict poststroke dementia with equivalent predictive validity. METHODS: Data were harmonized from 4 stroke studies (follow-up range, ≈12–18 months poststroke) from Hong Kong, the United States, the Netherlands, and France. Regression analysis was used to test 3 risk prediction models: the Cardiovascular Risk Factors, Aging and Dementia score, the Australian National University Alzheimer Disease Risk Index, and the Brief Dementia Screening Indicator. Model performance or discrimination accuracy was assessed using the C statistic or area under the curve. Calibration was tested using the Grønnesby and Borgan and the goodness-of-fit tests. RESULTS: The predictive accuracy of the models varied but was generally low compared with the original development cohorts, with the Australian National University Alzheimer Disease Risk Index (C-statistic, 0.66) and the Brief Dementia Screening Indicator (C-statistic, 0.61) both performing better than the Cardiovascular Risk Factors, Aging and Dementia score (area under the curve, 0.53). CONCLUSIONS: Dementia risk prediction models developed for the general population do not perform well in individuals with stroke. Their poor performance could have been due to the need for additional or different predictors related to stroke and vascular risk factors or methodological differences across studies (eg, length of follow-up, age distribution)

Effects of Acupuncture upon cerebral hemodynamics in cerebral small vessel disease: A pilot study

Background and aims: Recent preclinical studies and meta-analysis of clinical trials suggested that acupuncture may improve cognition in cerebral small vessel disease (CSVD). We investigated the cerebral hemodynamics of acupuncture in subjects with CSVD and compared its impact upon the cerebral hemodynamics in normal elderly subjects Methods: 10 subjects with CSVD (CSVD group) and 10 aged-matched control subjects who had no or insignificant CSVD (control group) were recruited. A single session of acupuncture was applied for 30 min in both groups. We assessed the effect of our acupuncture intervention on cerebral hemodynamics by transcranial Doppler ultrasound (TCD). Peak systolic velocity (PSV) and pulsatility index (PI) of the middle cerebral artery (MCA) were assessed Results: We observed that PSV increased by a maximum of 39% at 20 min (p<0.05), while there was no significant change in PI in the CSVD group during the acupuncture session. In the control group, although we observed no significant change in PSV during the acupuncture session, there was a significant decrease in PI by a maximum of 22% at 20 min (p<0.05). No adverse events were reported during or after the procedure. Conclusion: This study suggested that our acupuncture prescription was associated with an increase in cerebral blood flow in subjects with established moderate to severe CSVD yet without apparent impact on distal vascular resistance. While, in subjects with no or insignificant CSVD, it may reduce cerebral small vessel distal vascular resistance. A larger study is needed to confirm our findings

Diffusion MRI harmonization enables joint-analysis of multicentre data of patients with cerebral small vessel disease

10.1016/j.nicl.2021.102886NEUROIMAGE-CLINICAL3

Peak width of skeletonized mean diffusivity and its association with age-related cognitive alterations and vascular risk factors

Introduction: Only two studies investigated the associations between peak width of skeletonized mean diffusivity (PSMD) and age-related cognitive alterations, whereas none of the studies investigated the association with vascular risk factors. Methods: We evaluated 801 stroke- and dementia-free elderlies with baseline and 3-year follow-up assessments. Regression analyses were used to assess the association between age-related cognitive functions and PSMD. Simple mediation models were used to study the mediation effect of PSMD between vascular risk factors and age-related cognitive outcomes. Results: PSMD was negatively associated with processing speed at baseline and negatively associated with processing and memory scores at 3-year follow-up. The association between vascular risk factors and age-related cognition was mediated by PSMD, as well as other diffusion tensor imaging markers. Discussion: PSMD is preferred over other diffusion tensor imaging markers as it is sensitive to age-related cognitive alterations and calculation is fully automated. PSMD is proposed as a research tool to monitor age-related cognitive alterations

Peak width of skeletonized mean diffusivity and its association with age-related cognitive alterations and vascular risk factors

Introduction: Only two studies investigated the associations between peak width of skeletonized mean diffusivity (PSMD) and age-related cognitive alterations, whereas none of the studies investigated the association with vascular risk factors. Methods: We evaluated 801 stroke- and dementia-free elderlies with baseline and 3-year follow-up assessments. Regression analyses were used to assess the association between age-related cognitive functions and PSMD. Simple mediation models were used to study the mediation effect of PSMD between vascular risk factors and age-related cognitive outcomes. Results: PSMD was negatively associated with processing speed at baseline and negatively associated with processing and memory scores at 3-year follow-up. The association between vascular risk factors and age-related cognition was mediated by PSMD, as well as other diffusion tensor imaging markers. Discussion: PSMD is preferred over other diffusion tensor imaging markers as it is sensitive to age-related cognitive alterations and calculation is fully automated. PSMD is proposed as a research tool to monitor age-related cognitive alterations

High burden of cerebral white matter lesion in 9 Asian cities

10.1038/s41598-021-90746-xSCIENTIFIC REPORTS11

Tackling challenges in care of Alzheimer's disease and other dementias amid the COVID-19 pandemic, now and in the future

10.1002/alz.12143ALZHEIMERS & DEMENTIA16111571-158

Erratum to: Tackling challenges in care of Alzheimer's disease and other dementias amid the COVID-19 pandemic, now and in the future (Alzheimer's & Dementia, (2020), 16, 11, (1571-1581), 10.1002/alz.12143)

In the paper by Mok et al. (“Tackling challenges in care of Alzheimer's disease and other dementias amid the COVID-19 pandemic, now and in the future.”Alzheimer's Dement. 2020; 16: 1571-1581. https://doi.org/10.1002/alz.12143), an error occurred in the preparation of the paper for publication, requiring the following correction. In the initial publication of this article, Vorapun Senanarong, BSc, MD, was inadvertently omitted from the author group. The corrected author group and affiliations list appear above. We regret the error