Utility of Montreal Cognitive Assessment in Differentiating Dementia With Lewy Bodies From Alzheimer's Dementia

Neuropsychological Assessment for Early Detection and Diagnosis of Dementia: Current Knowledge and New Insights

Dementia remains an underdiagnosed syndrome, and there is a need to improve the early detection of cognitive decline. This narrative review examines the role of neuropsychological assessment in the characterization of cognitive changes associated with dementia syndrome at different states. The first section describes the early indicators of cognitive decline and the major barriers to their identification. Further, the optimal cognitive screening conditions and the most widely accepted tests are described. The second section analyzes the main differences in cognitive performance between Alzheimer's disease and other subtypes of dementia. Finally, the current challenges of neuropsychological assessment in aging/dementia and future approaches are discussed. Essentially, we find that current research is beginning to uncover early cognitive changes that precede dementia, while continuing to improve and refine the differential diagnosis of neurodegenerative disorders that cause dementia. However, neuropsychology faces several barriers, including the cultural diversity of the populations, a limited implementation in public health systems, and the adaptation to technological advances. Nowadays, neuropsychological assessment plays a fundamental role in characterizing cognitive decline in the different stages of dementia, but more efforts are needed to develop harmonized procedures that facilitate its use in different clinical contexts and research protocols.

Technical Review of Clinical Outcomes Assessments Across the Continuum of Alzheimer's Disease

INTRODUCTION

Insight into the relationship between concepts that matter to the people affected by Alzheimer's disease (AD) and the clinical outcome assessments (COAs) commonly used in AD clinical studies is limited. Phases 1 and 2 of the What Matters Most (WMM) study series identified and quantitatively confirmed 42 treatment-related outcomes that are important to people affected by AD.

METHODS

We compared WMM concepts rated as "very important" or higher to items included in COAs used commonly in AD studies.

RESULTS

Twenty COAs designed to assess signs, symptoms, and impacts across the spectrum of AD were selected for review. Among these 20 COAs, only 5 reflected 12 or more WMM concepts [Integrated Alzheimer's Disease Rating Scale (iADRS), Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory (ADCS-ADL), Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory-Mild Cognitive Impairment (ADCS-ADL-MCI), Alzheimer's Disease Composite Scores (ADCOMS), and Clinical Dementia Rating; Clinical Dementia Rating-Sum of Boxes (CDR/CDR-SB)]. Multiple symptoms and impacts of AD identified as important and meaningful in the WMM studies map only indirectly at best to 7 of the 20 most widely used COAs.

CONCLUSION

While many frequently used COAs in AD capture some concepts identified as important to AD populations and their care partners, overlap between any single measure and the concepts that matter to people affected by AD is limited. The highest singly matched COA reflects fewer than half (45%) of WMM concepts. Use of multiple COAs expands coverage of meaningful concepts. Future research should explore the content validity of AD COAs planned for AD trials based on further confirmation of the ecological validity of the WMM items. This research should inform development and use of core outcome sets that capture WMM items and selection or development of new companion tools to fully demonstrate clinically meaningful outcomes spanning WMM.

A Mini-Mental State Examination Formula May Help to Distinguish Alzheimer's Disease from Dementia with Lewy Bodies

Background:

Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB) differ in their memory, attention, and visuoconstructional characteristics. The subscales of the well-known Mini-Mental State Examination (MMSE) provide an opportunity to assess these characteristics. Previous research has shown that analysis of the MMSE subscale performance of AD and DLB patients helps to differentiate them.

Objective:

Study the MMSE scores of AD and DLB patients to see if the ability of previously reported analyses to differentiate them could be improved. Include other dementia patients for perspective.

Methods:

We studied the MMSEs of all patients seen in our clinics during an 18-month period. Different equations were studied, derived from the subscales of Memory (M, 3 points maximum), Attention (A, 5 points maximum), and Pentagon-copying (P, 1 point maximum).

Results:

We obtained 400 MMSEs, 136 from AD patients and 24 from DLB patients, scoring range 1–30. The equation P minus M provided the best discrimination between AD and DLB. Using a P-M score = 1 to identify AD, the positive predictive value was 0.97, negative predictive value 0.22, specificity 0.92, and sensitivity 0.43. As a secondary finding, the P-M = 1 equation was also helpful to differentiate AD from Parkinson’s disease dementia.

Conclusion:

Considering AD versus DLB in our clinic population, a demented patient who was unable to recall the three memory words on the MMSE but able to copy the intersecting pentagons had a 97% likelihood of having AD. Additional work is needed to improve the sensitivity of the P-M = 1 equation.

The gesture imitation test in dementia with Lewy bodies and Alzheimer's disease dementia

Objectives

Dementia with Lewy bodies (DLB) is the second most common type of neurodegenerative dementia following Alzheimer's disease dementia (ADD). This study investigated the diagnostic role of the gesture imitation test in detecting DLB and differentiating DLB from ADD.

Methods

A total of 63 patients with DLB, 93 patients with ADD, and 88 healthy controls were included in this study. All participants were administered the gesture imitation test, the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the clock drawing test (CDT), and other neuropsychological tests.

Results

The patients with DLB performed worse than the healthy controls in the global scores and on every item of the gesture imitation test (p < 0.001). The area under the curve (AUC) for the global scores was 0.889 (p < 0.001) in differentiating the DLB and control groups. Item 4 was a better discriminator, with a sensitivity of 79.37% and a specificity of 79.55%. The AUC for the global scores decreased to 0.593 and the difference was marginal (p = 0.079) in differentiating the DLB and ADD groups. The patients with DLB performed worse on Items 1 and 4 compared with the patients with ADD (p = 0.040, 0.004). The gesture imitation test was positively correlated with the scores of the MMSE (r = 0.355, p = 0.017), the MoCA (r = 0.382, p = 0.010), and the CDT (r = 0.407, p = 0.005) in patients with DLB.

Conclusion

The gesture imitation test is an easy, rapid tool for detecting DLB and has a role in differentiating DLB from ADD, especially in Items 1 and 4.

The Smart Aging Platform for Assessing Early Phases of Cognitive Impairment in Patients With Neurodegenerative Diseases

Background: Smart Aging is a serious game (SG) platform that generates a 3D virtual reality environment in which users perform a set of screening tasks designed to allow evaluation of global cognition. Each task replicates activities of daily living performed in a familiar environment. The main goal of the present study was to ascertain whether Smart Aging could differentiate between different types and levels of cognitive impairment in patients with neurodegenerative disease.

Methods: Ninety-one subjects (mean age = 70.29 ± 7.70 years)—healthy older adults (HCs, n = 23), patients with single-domain amnesic mild cognitive impairment (aMCI, n = 23), patients with single-domain executive Parkinson's disease MCI (PD-MCI, n = 20), and patients with mild Alzheimer's disease (mild AD, n = 25)—were enrolled in the study. All participants underwent cognitive evaluations performed using both traditional neuropsychological assessment tools, including the Mini-Mental State Examination (MMSE), Montreal Overall Cognitive Assessment (MoCA), and the Smart Aging platform. We analyzed global scores on Smart Aging indices (i.e., accuracy, time, distance) as well as the Smart Aging total score, looking for differences between the four groups.

Results: The findings revealed significant between-group differences in all the Smart Aging indices: accuracy (p < 0.001), time (p < 0.001), distance (p < 0.001), and total Smart Aging score (p < 0.001). The HCs outperformed the mild AD, aMCI, and PD-MCI patients in terms of accuracy, time, distance, and Smart Aging total score. In addition, the mild AD group was outperformed both by the HCs and by the aMCI and PD-MCI patients on accuracy and distance. No significant differences were found between aMCI and PD-MCI patients. Finally, the Smart Aging scores significantly correlated with the results of the neuropsychological assessments used.

Conclusion: These findings, although preliminary due to the small sample size, suggest the validity of Smart Aging as a screening tool for the detection of cognitive impairment in patients with neurodegenerative diseases.

Prevalence and clinical associations of tau in Lewy body dementias: A systematic review and meta-analysis

INTRODUCTION

Alzheimer's disease neuropathologies (amyloid-β and tau) frequently co-exist to varying degrees in Lewy body dementias (LBD), which include dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD).

OBJECTIVES

To investigate the prevalence of tau in DLB and PDD, and its associations with clinical outcomes.

METHODS

We searched the major electronic databases using the search term: ("dementia with Lewy bodies" OR "diffuse Lewy body disease" OR "Lewy body variant of Alzheimer's disease") AND ("tau protein" OR "tauopathy" OR "neurofibrillary tangle"), for relevant studies which evaluated tau in LBD. Forty-nine articles met the inclusion criteria for data extraction. Where appropriate, a random-effect meta-analysis was performed to obtain pooled estimates for prevalence and risk ratios (RR) or standardized mean differences (SMD) for clinical features, diagnostic accuracy and cognition.

RESULTS

Braak neurofibrillary tangle stage ≥ III was observed in 66% (n = 1511, 95%CI 60%-73%) of DLB and 52% (n = 433, 95%CI 27%-76%) of PDD at autopsy. Abnormal CSF phosphorylated-tau levels were present in 28% (n = 925, 95%CI 25%-31%) of DLB and 15% (n = 172, 95%CI 5%-24%) of PDD cases. Higher tau burden in DLB was associated with reduced likelihood of manifesting visual hallucinations (RR 0.56; 95%CI 0.40-0.77) and motor parkinsonism (RR 0.62; 95%CI 0.40-0.98), lower diagnostic accuracy of DLB during life (RR 0.49; 95%CI 0.38-0.64) and worse cognition prior to death (SMD 0.63; 95%CI 0.46-0.81).

CONCLUSIONS

Tau is common in LBD and may reduce clinical diagnostic accuracy in people with DLB. Prospective longitudinal studies are needed to understand the roles of co-morbid neuropathologies in Lewy body dementias.

Reducing falls among people living with dementia: A systematic review

Background

People diagnosed with dementia are at greater risk of falls. Given the increasing incidence of dementia globally, high quality and methodologically rigorous research is needed to inform evidence-based practice initiatives.

Aims

To describe the published literature related to describing, reducing or preventing fall incidences for people living with dementia including: (1) trends in the total number of intervention and non-intervention studies between 1997 and 2016; (2) the methodological quality of identified intervention studies; and (3) the effectiveness of interventions designed to reduce the incidence of falls among people living with dementia.

Methods

A systematic review of five databases was conducted to identify studies reporting any aspect of falls incidence for people with a diagnosis of dementia. Studies meeting the eligibility criteria were coded as intervention or non-intervention studies. Intervention studies were assessed using Cochrane’s Effective Practice and Organisation of Care tool. Data about the effectiveness of interventions meeting Effective Practice and Organisation of Care criteria were extracted.

Results

Seventy-two eligible studies were identified; 57 were non-intervention studies, and 15 were intervention studies. The number of published studies increased between 1997 and 2016, peaking in 2013 ( n = 10). Of the 15 intervention studies, seven studies met Effective Practice and Organisation of Care design criteria with one study rated low risk on all eight Effective Practice and Organisation of Care risk of bias domains. One high-risk exercise-based intervention study demonstrated a significant reduction in falls among people living with dementia.

Conclusions

There is currently insufficient evidence to endorse any intervention to reduce falls for people living with dementia in any setting. More high-quality intervention studies are needed.

Diagnosis and Management of Cognitive and Behavioral Changes in Dementia With Lewy Bodies

OPINION STATEMENT

Proper diagnosis of dementia with Lewy bodies (DLB) in clinical practice remains suboptimal as many cases are misdiagnosed, usually as Alzheimer disease (AD) or Parkinson's disease (PD) and, in rare cases, psychosis. Therefore, it is important for patients with dementia to be thoroughly evaluated by a specialist who is familiar with current diagnostic tests and treatment options. New diagnostic criteria from the Dementia with Lewy Bodies Consortium have been developed to increase diagnostic sensitivity for DLB (Diagnosis and management of dementia with Lewy bodies: fourth consensus report of the DLB Consortium; McKeith et al.; Neurology, 89(1): 88-100). REM sleep behavior disorder (RBD) has been studied more thoroughly in correlation with DLB and is now considered a core feature. D2 receptor blocking antipsychotics, which can cause severe antipsychotic sensitivity, are now rarely prescribed for treatment. Therefore, severe antipsychotic sensitivity, which was a suggestive criterion for DLB diagnosis, is now listed as a supportive feature. Reduced DAT uptake in basal ganglia demonstrated by SPECT or PET imaging has high specificity (90%) for distinguishing DLB from AD. Reduced uptake on metaiodobenzylguanidine myocardial scintigraphy correlates with reduced postganglionic sympathetic cardiac innervation in Lewy body diseases, which can increase specificity for discriminating probable DLB from probable AD in milder cases of dementia. However, the latter is more commonly used in Japan and is not used in the USA. The evidence supporting the benefit of other therapeutic modalities is limited in DLB due to lack of extensive studies. There are no FDA-approved medications for the treatment of DLB, although some effective drugs have been used off label to treat various symptoms.