A Longitudinal Study of Neurocognition in Dementia with Lewy Bodies Compared to Alzheimer's Disease

Differences in Cognitive Trajectories of Dementia: Comparison of Alzheimer's Disease Dementia and Dementia with Lewy Bodies in a Korean Patient Cohort

INTRODUCTION

Prediction of the dementia progression is important for patient management. We aimed to investigate the cognitive trajectories of Alzheimer's disease dementia (ADD) and dementia with Lewy bodies (DLB) according to the initial structural change measured by comprehensive visual rating scales (CVRS).

METHODS

We retrospectively included the patients who initially visited the Dementia Clinic of Chonnam National University Hospital between 2010 and 2012. All patients underwent dementia workup including neuropsychological battery (Seoul Neuropsychological Screening Battery, SNSB). We recruited the participant who underwent SNSB annually for 3 years successively. A total of 136 patients of ADD and 63 patients of DLB were included for analysis. We analyzed the decline pattern of the cognitive profile according to the initial brain structural changes.

RESULTS

The general cognitive trajectories between ADD and DLB patients were not different. However, DLB patients showed more rapid decline of cognitive function in language and related function, visual memory function, and frontal executive function. The scores were lower in participants with DLB with the lesser atrophy group in attention, visuospatial function, and frontal executive function. In analysis of the cognitive trajectories, the visual memory domain declined rapidly in the DLB with lesser atrophy group compared with the ADD with lesser atrophy group.

CONCLUSION

We founded that the differences in the visual cognitive profile in ADD and DLB patients in serial follow-up of neuropsychological tests. It is prominent in the mild structural change group of ADD and DLB.

Clinical characteristics of pathological confirmed prodromal dementia with Lewy bodies

INTRODUCTION

Misdiagnosis rate of Dementia with Lewy Bodies (DLB) remains high despite being second most common cause of neurodegenerative dementia. To date, understanding of clinical profile of pathologically confirmed prodromal DLB remains limited. The main objective of this study was to describe and compare it with pathologically confirmed Alzheimer's disease (AD).

METHODS

We accessed the National Alzheimer's Coordinating Center database from 2005 to December 2022 data freeze and included 111 and 501 prodromal DLB and AD patients respectively. First visit data was analyzed.

RESULTS

Clinician-determined memory impairment is common in prodromal DLB (>70%) but associated with higher risk for AD diagnosis (OR 0.355, p = 0.0003). DLB had a higher proportion of non-amnestic mild cognitive impairment (MCI) diagnoses but statistically insignificance in differentiating the two. Inattention (OR 2.273, p = 0.0015), and neuropsychiatric features, such as visual hallucinations (OR 11.98, p < 0.0001), depressed mood (OR1.709, p = 0.0292), apathy (1.824, p = 0.0345), and night/REM sleep behaviors, are associated with DLB diagnosis. Hallucinations are infrequent (7-11%). Motor symptoms, particularly gait disorders (OR 4.570, p < 0.001), falls (OR3.939, p = 0.0003), tremors (OR2.237, p = 0.0154), slowness (OR3.573, p < 0.0001), and parkinsonism signs (OR2.443, p < 0.0001), are common. 32% showed no parkinsonism during initial presentation. Neuropsychological examination revealed less impaired memory and language but impaired executive function in DLB.

CONCLUSION

In clinical practice, it is important to note that memory symptoms although being higher risk associated with AD diagnosis, are prominent in prodromal DLB. Psychosis is infrequent, and non-amnestic MCI is not necessarily associated with higher risk of DLB diagnosis. A careful clinical approach is key to improve the diagnosis of prodromal DLB.

Inflammatory Biomarkers in Newly Diagnosed Patients With Parkinson Disease and Related Neurodegenerative Disorders

BACKGROUND AND OBJECTIVES

Neuroinflammation contributes to Parkinson disease (PD) pathology, and inflammatory biomarkers may aid in PD diagnosis. Proximity extension assay (PEA) technology is a promising method for multiplex analysis of inflammatory markers. Neuroinflammation also plays a role in related neurodegenerative diseases, such as dementia with Lewy bodies (DLB) and Alzheimer disease (AD). The aim of this work was to assess the value of inflammatory biomarkers in newly diagnosed patients with PD and in patients with DLB and AD.

METHODS

Patients from the Norwegian ParkWest and Dementia Study of Western Norway longitudinal cohorts (PD, n = 120; DLB, n = 15; AD, n = 27) and 44 normal controls were included in this study. A PEA inflammation panel of 92 biomarkers was measured in the CSF. Disease-associated biomarkers were identified using elastic net (EN) analysis. We assessed the discriminatory power of disease-associated biomarkers using receiver operating characteristic (ROC) curve analysis and estimated the optimism-adjusted area under the curve (AUC) using the bootstrapping method.

RESULTS

EN analysis identified 9 PEA inflammatory biomarkers (ADA, CCL23, CD5, CD8A, CDCP1, FGF-19, IL-18R1, IL-6, and MCP-2) associated with PD. Seven of the 9 biomarkers were included in a diagnostic panel, which was able to discriminate between those with PD and controls (optimism-adjusted AUC 0.82). Our 7-biomarker PD panel was also able to distinguish PD from DLB and from AD. In addition, 4 inflammatory biomarkers were associated with AD and included in a panel, which could distinguish those with AD from controls (optimism-adjusted AUC 0.87). Our 4-biomarker AD panel was also able to distinguish AD from DLB and from PD.

DISCUSSION

In our exploratory study, we identified a 7-biomarker panel for PD and a 4-biomarker panel for AD. Our findings indicate potential inflammation-related biomarker candidates that could contribute toward PD-specific and AD-specific diagnostic panels, which should be further explored in other larger cohorts.

Combining Physical and Cognitive Functions to Discriminate Level of Gait Independence in Hospitalized Patients with Alzheimer's Disease

INTRODUCTION

Both physical and cognitive functions are required to be assessed to determine the level of gait independence in patients with Alzheimer's disease (AD); nonetheless, a method to achieve this assessment has not been established. This study aimed to investigate the accuracy of an assessment method that combined muscle strength, balance ability, and cognitive function parameters in discriminating the level of gait independence in a real-world setting in hospitalized patients with AD.

METHODS

In this cross-sectional study, 63 patients with AD (mean age: 86.1 ± 5.8 years) were classified into three groups according to their gait level: independent, modified independent (independent walking with walking aids), and dependent groups. Discrimination accuracy was calculated for single items of muscle strength, balance ability, and cognitive function tests and for combinations of each.

RESULTS

The combined accuracy of muscle strength, balance ability, and cognitive function had a positive predictive value of 100.0% and a negative predictive value of 67.7% between the independent and modified independent groups. The positive and negative predictive values were 100.0% and 72.4%, respectively, between the modified independent and dependent groups.

CONCLUSION

This study emphasizes the importance of assessing the level of gait independence in a real-world setting in patients with AD from the perspective of both physical and cognitive functions and proposes a novel method for discriminating an optimal state.

Neuropsychological Impairments and Their Cognitive Architecture in Mild Cognitive Impairment (MCI) with Lewy Bodies and MCI-Alzheimer's Disease

OBJECTIVE

The present study aimed to clarify the neuropsychological profile of the emergent diagnostic category of Mild Cognitive Impairment with Lewy bodies (MCI-LB) and determine whether domain-specific impairments such as in memory were related to deficits in domain-general cognitive processes (executive function or processing speed).

METHOD

Patients (n = 83) and healthy age- and sex-matched controls (n = 34) underwent clinical and imaging assessments. Probable MCI-LB (n = 44) and MCI-Alzheimer's disease (AD) (n = 39) were diagnosed following National Institute on Aging-Alzheimer's Association (NIA-AA) and dementia with Lewy bodies (DLB) consortium criteria. Neuropsychological measures included cognitive and psychomotor speed, executive function, working memory, and verbal and visuospatial recall.

RESULTS

MCI-LB scored significantly lower than MCI-AD on processing speed [Trail Making Test B: p = .03, g = .45; Digit Symbol Substitution Test (DSST): p = .04, g = .47; DSST Error Check: p < .001, g = .68] and executive function [Trail Making Test Ratio (A/B): p = .04, g = .52] tasks. MCI-AD performed worse than MCI-LB on memory tasks, specifically visuospatial (Modified Taylor Complex Figure: p = .01, g = .46) and verbal (Rey Auditory Verbal Learning Test: p = .04, g = .42) delayed recall measures. Stepwise discriminant analysis correctly classified the subtype in 65.1% of MCI patients (72.7% specificity, 56.4% sensitivity). Processing speed accounted for more group-associated variance in visuospatial and verbal memory in both MCI subtypes than executive function, while no significant relationships between measures were observed in controls (all ps > .05).

CONCLUSIONS

MCI-LB was characterized by executive dysfunction and slowed processing speed but did not show the visuospatial dysfunction expected, while MCI-AD displayed an amnestic profile. However, there was considerable neuropsychological profile overlap and processing speed mediated performance in both MCI subtypes.

Clinical Trajectories at the End of Life in Autopsy-Confirmed Dementia Patients With Alzheimer Disease and Lewy Bodies Pathologies

BACKGROUND AND OBJECTIVES

Evaluating and understanding the heterogeneity in dementia course has important implications for clinical practice, health care decision-making, and research. However, inconsistent findings have been reported with regard to the disease courses of the 2 most common dementias: Alzheimer disease (AD) and dementia with Lewy bodies (DLB). Using autopsy-confirmed diagnoses, we aimed to examine the disease trajectories in the years before death among patients with dementia with pure AD, pure DLB, or mixed (AD and DLB) pathologies.

METHODS

The current retrospective longitudinal study included 62 participants with autopsy-confirmed diagnoses of pure AD (n = 34), mixed AD and DLB (AD + DLB; n = 17), or pure DLB (n = 11) from the Predictors 2 Cohort Study, a prospective, clinic-based, cohort of patients with dementia. Generalized estimating equation models, with time zero at death, were used to examine the trajectory of cognition (Folstein Mini-Mental State Examination [MMSE]), function (activities of daily living [ADL]), and Dependence Scale among patients with different autopsy-confirmed diagnosis (pure AD, AD + DLB, and pure DLB). The models were adjusted for age, sex, education, and baseline features including extrapyramidal signs, MMSE, ADL, and Dependence Scale.

RESULTS

The participants on average received 9.4 ± 4.6 assessments at 6-month intervals during a mean 5.4 ± 2.9 years of follow-up. The 3 groups were similar in both cognition and function status at baseline. Cognition and function were highly correlated among patients with AD + DLB but not in pure AD or pure DLB at baseline. Patients of the 3 groups all declined in both cognition and function but had different trajectories of decline. More specifically, the patients with pure DLB experienced approximately double the rate of both cognitive decline and functional decline than the patients with pure AD, and the mixed pathology group showed double the rate of functional decline as compared to pure AD.

DISCUSSION

In this longitudinal study, we found that among patients with dementia, those with Lewy body pathology experienced faster cognitive and functional decline than those with pure AD pathology.

Validation of the National Alzheimer's Coordinating Center (NACC) Lewy Body Disease Module neuropsychological tests

INTRODUCTION

This study assessed the construct validity and clinical utility of the National Alzheimer's Coordinating Center Lewy Body Dementia (LBD) Module, consisting of the Speeded Attention and Noise Pareidolia Tasks.

METHODS

Participants included 459 older adults diagnosed as cognitively normal (n = 202), or with non-amnestic mild cognitive impairment (n = 61), amnestic mild cognitive impairment (n = 96), Alzheimer's disease dementia (n = 44), or LBD (n = 56).

RESULTS

Speeded Attention demonstrated strong convergent validity and moderate discriminant validity when compared to established neuropsychological tests. Noise Pareidolia demonstrated strong discriminant validity, but limited convergent validity. Noise Pareidolia scores were significantly lower in those with reported hallucinations, delusions, or REM sleep behavior disorder symptoms. LBD Module tests discriminated well between cognitively normal adults and those with LBD.

DISCUSSION

The LBD Module demonstrates promising construct validity and clinical utility, which support its use across research and clinical settings.

A retrospective multicentre cohort study of the performances on attention tests in outpatients with cognitive dysfunctions without delirium

OBJECTIVE

Attention is the cardinal feature of delirium, but attentional domains may also be affected by dementia and its severity. It is, therefore, of interest to study the correlation between the severity of cognitive impairment in non-delirious patients and different measurements of attentional performance, to identify attention subdomains less affected by severity of cognitive impairment.

METHODS

Neuropsychological data from non-delirious outpatients (age ≥ 65 years), presenting at two memory clinics were analysed retrospectively. Scores for selective, divided, and sustained attention were correlated with cognitive impairment as defined by the score of the Mini-Mental State Examination.

RESULTS

A total of 1658 outpatients were included. The mean age was 77.15 (± 8.17) years, with a mean MMSE score of 22.67 (± 4.91). Compared to the type of attention, the tests that are less influenced by the severity of cognitive impairment are those of selective attention, in particular the Digit Span Forward (DSF).

CONCLUSIONS

This is the first study to correlate deficits in attention subdomains with the degree of cognitive impairment in non-delirious patients. The results suggest that measurements of selective attention (i.e. DSF) might be better suited to discriminate delirium from dementia. Indeed, a lower score on these tests might be indicative of an acute change and worsening of the baseline inattention and a longitudinal monitoring of these changes might be used to determine the delirium resolution.

Influence of Subject-Specific Effects in Longitudinal Modelling of Cognitive Decline in Alzheimer's Disease

BACKGROUND

Accurate longitudinal modelling of cognitive decline is a major goal of Alzheimer's disease and related dementia (ADRD) research. However, the impact of subject-specific effects is not well characterized and may have implications for data generation and prediction.

OBJECTIVE

This study seeks to address the impact of subject-specific effects, which are a less well-characterized aspect of ADRD cognitive decline, as measured by the Alzheimer's Disease Assessment Scale's Cognitive Subscale (ADAS-Cog).

METHODS

Prediction errors and biases for the ADAS-Cog subscale were evaluated when using only population-level effects, robust imputation of subject-specific effects using model covariances, and directly known individual-level effects fit during modelling as a natural control. Evaluated models included pre-specified parameterizations for clinical trial simulation, analogous mixed-effects regression models parameterized directly, and random forest ensemble models. Assessment used a meta-database of Alzheimer's disease studies with validation in simulated synthetic cohorts.

RESULTS

All models observed increases in variance under imputation leading to increased prediction error. Bias decreased with imputation except under the pre-specified parameterization, which increased in the meta-database, but was attenuated under simulation. Known fitted subject effects gave the best prediction results.

CONCLUSION

Subject-specific effects were found to have a profound impact on predicting ADAS-Cog. Reductions in bias suggest imputing random effects assists in calculating results on average, as when simulating clinical trials. However, reduction in error emphasizes population-level effects when attempting to predict outcomes for individuals. Forecasting future observations greatly benefits from using known subject-specific effects.

Challenges in Predicting Cognitive Decline in Dementia with Lewy Bodies

Despite being the second most common form of neurodegenerative dementia, dementia with Lewy bodies (DLB) is under-recognized and carries a worse prognosis than other subtypes of the condition. Cognitive impairment is a cardinal feature of all types of dementia and DLB presents with a distinct profile with deficits in attention, executive function, and visuoperceptual abilities. This difference from Alzheimer's disease and the common presence of neuropsychiatric symptoms may lead to challenges in predicting cognitive decline in this patient population. Firstly, the diagnosis of DLB is often delayed in clinical practice leading to variability from which time point in the disease course cognitive decline is measured. Secondly, the most frequently used measurement tools for cognitive difficulties focus on memory and naming rather than the domains affected by DLB. While there is now largely a consensus which tools are useful in diagnosing DLB, their validity in assessing deteriorating cognition is less clear. Thirdly, the presence of fluctuating cognition, the propensity to develop delirium episodes, as well as difficulties in distinguishing the two entities in clinical practice make it difficult to predict the disease course. Sleep disturbances are likely to influence cognitive decline but require further study in patients within established DLB. Fourthly, as in most cases of dementia, neuropathological comorbidities are frequently present in DLB. While the influence of Alzheimer's pathology on cognitive decline in DLB is comparatively well understood, the impact of other pathologies remains unclear. The recent definition of research criteria for mild cognitive impairment in DLB could facilitate earlier diagnosis and more structured follow-up. Assessment tools measuring cognitive domains predominantly affected in DLB need to be more consistently used in longitudinal studies and clinical practice, as well as concurrent measures of fluctuations in cognition. Greater availability of biomarkers and digital healthcare solutions can play an important role in enabling more accurate monitoring and prediction of cognitive decline in DLB.

Progression of Clinical Features in Lewy Body Dementia Can Be Detected Over 6 Months

OBJECTIVE

This study aimed to quantify the trajectory and magnitude of change of the key clinical features and corresponding symptom domains of dementia with Lewy bodies (DLB) and Parkinson disease dementia (PDD), including global cognition, parkinsonism, recurrent visual hallucinations, cognitive fluctuations, and sleep disturbance.

METHODS

One hundred sixteen patients with Lewy body dementia (DLB = 72, PDD = 44) underwent assessment at baseline and 3 and 6 months as part of a prospective multicenter randomized controlled trial. Linear mixed models were constructed for core outcome measures using the Mini-Mental State Examination (MMSE), motor section of the Unified Parkinson's Disease Rating Scale (UPDRS-III), Dementia Cognitive Fluctuations Scale (DCFS), and Neuropsychiatric Inventory (NPI).

RESULTS

Within the time frame of our study (6 months), we were able to identify a significant cognitive decline of 1.3 points on the MMSE (p = 0.002) and significant worsening of motor parkinsonism with an increase in UPDRS-III score of 3.2 points (p = 0.018). Fluctuation severity also increased using the DCFS with a 6-month change in score of 1.3 points (p = 0.001). Uniquely, a signal for increased severity of sleep symptoms of 1.2 points (NPI-sleep) was also detectable (p = 0.04). Significant changes in neuropsychiatric symptoms were not detected. There was no difference in rates of change of scores between DLB and PDD.

DISCUSSION

Clinically significant rates of change in core clinical features can be detected and quantified in Lewy body dementia over a relatively short period (6 months) using common clinical instruments and thus may be useful as clinical endpoints for therapeutic trials of disease-modifying and symptomatic agents.

Prodromal Dementia With Lewy Bodies: Clinical Characterization and Predictors of Progression

Objective

The objective of this study was to examine clinical characteristics, cognitive decline, and predictors for time to dementia in prodromal dementia with Lewy bodies with mild cognitive impairment (MCI‐LB) compared with prodromal Alzheimer's disease (MCI‐AD).

Methods

We included 73 MCI‐LB patients (12% female; 68 ± 6 years; Mini Mental State Examination, 27 ± 2) and 124 MCI‐AD patients (48% female; 68 ± 7 years; Mini Mental State Examination, 27 ± 2) from the Amsterdam Dementia Cohort. Follow‐up was available for 61 MCI‐LB patients and all MCI‐AD patients (3 ± 2 years). We evaluated dementia with Lewy bodies core features, neuropsychiatric symptoms, caregiver burden (Zarit caregiver burden interview), MRI, apolipoprotein genotype, and cerebrospinal fluid biomarkers (tau/Aβ_1–42 ratio). Longitudinal outcome measures included cognitive slopes (memory, attention, executive functions, and language and visuospatial functions) and time to dementia.

Results

Parkinsonism was the most frequently present core feature in MCI‐LB (69%). MCI‐LB patients more often had neuropsychiatric symptoms and scored higher on ZARIT when compared with the MCI‐AD patients. Linear mixed models showed that at baseline, MCI‐LB patients performed worse on nonmemory cognitive domains, whereas memory performance was worse in MCI‐AD patients. Over time, MCI‐LB patients declined faster on attention, whereas MCI‐AD patients declined faster on the Mini Mental State Examination and memory. Cox proportional hazards regressions showed that in the MCI‐LB patients, lower attention (hazard ratio [HR] = 1.6; 95% confidence interval [CI], 1.1–2.3) and more posterior cortical atrophy (HR = 3.0; 95% CI, 1.5–5.8) predicted shorter time to dementia. In the MCI‐AD patients, worse performance on memory (HR = 1.1; 95% CI, 1.0–1.2) and executive functions (HR = 1.3; 95% CI, 1.0–1.6) were independently associated with time to Alzheimer's dementia.

Conclusion

MCI‐LB patients have distinct neuropsychiatric and cognitive profiles with prominent decline in attention when compared with MCI‐AD patients. Our results highlight the importance of early diagnosis because symptoms already have an impact in the prodromal stages. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Understanding and predicting the longitudinal course of dementia

PURPOSE OF REVIEW

To date, most research in dementia has focused either on the identification of dementia risk prediction or on understanding changes and predictors experienced by individuals before diagnosis. Despite little is known about how individuals change after dementia diagnosis, there is agreement that changes occur over different time scales and are multidomain. In this study, we present an overview of the literature regarding the longitudinal course of dementia.

RECENT FINDINGS

Our review suggests the evidence is scarce and findings reported are often inconsistent. We identified large heterogeneity in dementia trajectories, risk factors considered and modelling approaches employed. The heterogeneity of dementia trajectories also varies across outcomes and domains investigated.

SUMMARY

It became clear that dementia progresses very differently, both between and within individuals. This implies an average trajectory is not informative to individual persons and this needs to be taken into account when communicating prognosis in clinical care. As persons with dementia change in many more ways during their patient journey, heterogeneous disease progressions are the result of disease and patient characteristics. Prognostic models would benefit from including variables across a number of domains. International coordination of replication and standardization of the research approach is recommended.