Distinguishing between Vascular Dementia and Alzheimer's Disease by Means of the WAIS: A Meta-analysis

The MindMoves Trial: Cross-Sectional Analyses of Baseline Vascular Risk and Cognition in Older Women with Cardiovascular Disease

Background

Vascular diseases, including atherosclerotic cardiovascular disease (ASCVD) and stroke, increase the risk of Alzheimer's disease and cognitive impairment. Serum biomarkers, such as brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and insulin-like growth factor 1 (IGF-1), may be indicators of cognitive health.

Objective

We examined whether vascular risk was associated with levels of cognition and serum biomarkers in older women with cardiovascular disease (CVD).

Methods

Baseline data from a lifestyle trial in older women (n = 253) with CVD (NCT04556305) were analyzed. Vascular risk scores were calculated for ASCVD (ASCVD risk estimator) and stroke (CHA2DS2-VASc) based on published criteria. Cognition-related serum biomarkers included BDNF, VEGF, and IGF-1. Cognition was based on a battery of neuropsychological tests that assessed episodic memory, semantic memory, working memory, and executive function. A series of separate linear regression models were used to evaluate associations of vascular risk scores with outcomes of cognition and serum biomarkers. All models were adjusted for age, education level, and racial and ethnic background.

Results

In separate linear regression models, both ASCVD and CHA2DS2-VASc scores were inversely associated with semantic memory (β= -0.22, p = 0.007 and β= -0.15, p = 0.022, respectively), with no significant findings for the other cognitive domains. There were no significant associations between vascular risk scores and serum biomarkers.

Conclusions

Future studies should prospectively examine associations between vascular risk and cognition in other populations and additionally consider other serum biomarkers that may be related to vascular risk and cognition.

Neuropsychological differential diagnosis of Alzheimer's disease and vascular dementia: a systematic review with meta-regressions

Introduction

Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them.

Methods

We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots.

Results

We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (β g = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (β g = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (β g = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (β g = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (β g = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (β g = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50).

Conclusion

Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.

Predictive potential of preoperative electroencephalogram for neuropsychological change following subthalamic nucleus deep brain stimulation in Parkinson's disease

BACKGROUND

Deep brain stimulation of the bilateral subthalamic nucleus (STN-DBS) improves motor fluctuation and severe dyskinesia in advanced Parkinson's disease (PD). Effects on non-motor symptoms, such as neurocognitive side effects, can also influence the quality of life of both patients with PD and caregivers. Predictive quantitative factors associated with postoperative neurocognitive deterioration therefore warrant further attention. Here, we evaluated preoperative electroencephalogram (EEG) as a predictive marker for changes in neurocognitive functions after surgery.

METHODS

Scalp EEG was recorded preoperatively from 17 patients with PD who underwent bilateral STN-DBS. Global relative power in the theta, alpha, and beta bands was calculated. Cognitive function was assessed with neuropsychological batteries preoperatively and 1 year after STN-DBS.

RESULTS

Performance on the Symbol Search subtest of the WAIS III declined 1 year after DBS. The theta band was chosen for analysis with a 40% cutoff point for increased (≥ 40%) and decreased (< 40%) power. No significant differences between the two groups in baseline performance on most neuropsychological batteries were found, except for the Digit Symbol Coding subtest of the WAIS III. Changes in visual spatial functions were significantly different between groups. The increased theta band power group demonstrated a significant deterioration in performance on the WAIS III Matrix Reasoning subtest and the copy and immediate recall tasks of the Rey-Osterrieth complex figure test.

CONCLUSIONS

These findings suggest that preoperative increases in theta power are related to postoperative deterioration of visuospatial function, which indicates the predictive potential of preoperative quantitative EEG for neurocognitive changes after STN-DBS.

Preclinical cognitive trajectories differ for Alzheimer's disease and vascular dementia

We investigated differences between Alzheimer's disease (AD) and vascular dementia (VaD) from the appearance of the first cognitive symptoms, focusing on both time of onset and rate of accelerated decline for different cognitive functions before dementia diagnosis. Data from a longitudinal population-based study were used, including 914 participants (mean age = 82.0 years, SD = 5.0) tested with a cognitive battery (word recall and recognition, Block Design, category fluency, clock reading) on up to four occasions spanning 10 years. We fit a series of linear mixed effects models with a change point to the cognitive data, contrasting each dementia group to a control group. Significant age-related decline was observed for all five cognitive tasks. Relative to time of diagnosis, the preclinical AD persons deviated from the normal aging curve earlier (up to 9 years) compared to the preclinical VaD persons (up to 6 years). However, once the preclinical VaD persons started to decline, they deteriorated at a faster rate than the preclinical AD persons. The results have important implications for identifying the two dementia disorders at an early stage and for selecting cognitive tasks to evaluate treatment effects for persons at risk of developing AD and VaD.

The subjective experience of personhood in dementia care settings

Within the social psychological understanding of dementia, individuals' personhood is central. A respect for personhood has been linked to successful person-centred care, yet research exploring subjective personhood in dementia is scarce. This study aimed to understand personhood by exploring the subjective experiences of those with dementia. Seven individuals with dementia were interviewed and interpretative phenomenological analysis was used to identify themes across accounts. Themes identified were: (1) working out the system and adapting in order to survive it--the 'peoplehood' of the system; (2) using past and future roles and experiences to manage the present--the transient nature of personhood; (3) being both an individual and a member of a group--the conflict of a dual role. The themes highlighted showed that individuals with dementia supported their personhood by drawing on their own, others' and the system's resources. The findings are discussed and links with existing literature and clinical implications are considered.

Distinguishing Alzheimer's disease from vascular dementia: an exploration of five cognitive domains

The disease process of Alzheimer's disease (AD) and Vascular Dementia (VaD) are dissimilar; however, the cognitive presentations may be difficult to distinguish as they may present in tandem or result in similar deficits despite different pathogenesis. This study examined the efficacy of memory, confrontational naming, visuoconstructional ability, processing speed, and executive functioning in differentiating AD from VaD. Delayed verbal memory, visuoconstructional ability, and confrontational naming as measured by WMS-R Logical Memory II, WAIS-R Block Design (BD), and Boston Naming Test, respectively, were most effective in discriminating between these two disorders. Results indicated AD was best classified by BD, and BD was the most sensitive to AD-related pathogenesis. Delayed memory and confrontational naming were highly implicated in each subtype, suggesting they are sensitive to each disease process, thus reducing the reliability of utilizing them as sole differentiating agents.

Screening and case-finding tools for the detection of dementia. Part II: evidence-based meta-analysis of single-domain tests

AIM

To evaluate the diagnostic validity of single-domain cognitive tests for detecting dementia. These methods were defined as those that focus mainly on one domain of cognitive function such as orientation, memory, or executive function.

METHODS

A meta-analysis of robust studies was conducted. There were 15 categories of single-domain methods assessed in 45 analyses, including 27 performed head-to-head against the Mini-Mental State Examination (MMSE). Thirteen studies took place in community settings, 9 in primary care, and 23 in specialist settings.

RESULTS

In community settings, single-domain cognitive tests helped detect 64.2% of all dementias. In this setting, specificity (Sp) was 84.9%, positive predictive value (PPV) was 57.1%, and negative predictive value (NPV) was 88.3%. This was significantly less accurate than the MMSE itself. The optimal individual method was the memory impairment screen (MIS). In primary care, the sensitivity (Se) and specificity of single-domain tests were 69.5% and 82.5%, respectively. The PPV and NPV were 36.5% and 95.8%. Considered together, these methods were less specific but equally sensitive as the MMSE when applied in primary care. Here, the most successful methods were the selective reminding test (SRT) and clock drawing test, the latter having data from independent samples. In specialist settings, single-domain methods had a Se of 76.6%, a Sp of 81.9%, a PPV 80.8%, and a NPV 74.9%. This represented almost equivalent accuracy to the MMSE. The optimal method for specialist settings (based on accuracy alone) was the memory alteration test.

CONCLUSION

Brief single-domain methods offer diagnostic performance for detection of dementia that is surprisingly close to that offered by cognitive batteries such as the MMSE. As a method of screening or as part of a diagnostic algorithm, brief single-domain tests may be an efficient first step in identifying cognitive impairment.

Identification of dementia in epidemiological research: a study on the usefulness of various data sources

BACKGROUND AND AIMS

Prevalence and incidence ratios of dementia in epidemiological studies vary according to the data source used. Medical records, cognitive tests, and registry information are sources frequently used to differentiate dementia from normal aging. The aim of the present study was to compare the identification of dementia from these different sources with that from consensus diagnosis.

METHODS

498 elderly people (age range 70-81 at baseline) enrolled in a Swedish population-based longitudinal twin study (Gender) were evaluated on physical and mental health and interviewed for their socio-demographic background three times during an eight-year period. Reviews of medical records and the Swedish Discharge Registry (DR) were conducted. The 10th percentile was used to differentiate between dementia and non-dementia in all cognitive tests. Scores of 24 or below on the Mini-Mental State Examination (MMSE) (range 1-30) indicated dementia. A consensus conference diagnosed dementia on the basis of total information. The consensus diagnosis was used as the gold standard.

RESULTS

MMSE scores (sensitivity 64%, specificity 96%, kappa 0.65) and the review of medical records (sensitivity 57%, specificity 99%, kappa 0.65) were good sources for dementia identification. The precision of medical records increased when recordings of cognitive impairment were included (sensitivity 83%, specificity 98%, kappa 0.84). The discharge registry had low sensitivity (26%) and kappa coefficient (0.31).

CONCLUSIONS

The present study shows that both review of medical records and MMSE scores are good although not perfect identifiers of dementia. The discharge registry is an uncertain source of dementia identification.

The Dementia Rating Scale (DRS) in the diagnosis of vascular dementia

The Dementia Rating Scale (DRS) is considered a very useful instrument to assess patients with dementia. The tasks are grouped into five subscales, each one evaluating different cognitive areas, namely: Attention, Initiation/Perseveration (I/P), Construction, Conceptualization and Memory.

High risk neurological gait syndrome and vascular dementia

We defined a 'high-risk neurological gait' (HRNG) syndrome based on presence of any one of hemiparetic, frontal, and unsteady gaits, and examined its validity to predict vascular dementia (VD) over 3 and 5 years in 399 nondemented older adults, age 75 and over. Cox analysis was used to estimate hazard ratios (HR) for VD adjusted for potential confounders. At baseline, 54 subjects had HRNG. 14 subjects developed VD over 3 years and 25 by 5 years. HRNG predicted risk of VD within the first three (HR 3.3, 95% CI 1.8-5.9) and five years (HR 2.7, 95% CI 1.7-4.2). Including executive dysfunction (Digit symbol scores <16) improved validity; subjects with HRNG and executive dysfunction (HR 12.5, 95% CI 5.5-28.4) or either (HR 5.9, 95% CI 3.6-9.7) had higher risk of VD over five years. Diagnosing HRNG is a clinically relevant approach to identifying older adults at high risk of VD over short intervals.